Bioactive Natural Products against Prostate Cancer: Mechanism of Action and Autophagic/Apoptotic Molecular Pathways Katerina Gioti, Roxane Tenta
Abstract Prostate cancer is one of the leading causes of death worldwide for men. There is increasing evidence that diet and lifestyle play a crucial role in prostate cancer biology and tumorigenesis. Due to the fact that conventional chemotherapy is not adequately effective against prostate cancer and has severe side effects, numerous in vitrostudies have been conducted in order to identify the potent cytotoxic or chemopreventive activity of naturally occurring compounds and their respective molecular mechanisms of action. In this context, many natural compounds isolated from plants have been found to inhibit cancer growth and to induce cell cycle arrest, suppress angiogenesis, and promote apoptotic or autophagic cell death. Therefore, in this article, the most promising bioactive natural products and their respective mechanisms of action for the prevention or/and treatment of prostate cancer are presented.
A monoterpene, unique component of thyme honeys, induces apoptosis in prostate cancer cells via inhibition of NF-[kappa]B activity and IL-6 secretion.
Abstract We have previously demonstrated that Greek thyme honey inhibits significantly the cell viability of human prostate cancer cells. Herein, 15 thyme honey samples from several regions of Greece were submitted to phytochemical analysis for the isolation, identification and determination (through modern spectral means) of the unique thyme honey monoterpene, the compound trihydroxy ketone E-4-(1,2,4-trihydroxy-2,6,6- trimethylcyclohexyl)-but-3-en-2-one.
We investigated the anti-growth and apoptotic effects of the trihydroxy ketone on PC-3 human androgen independent prostate cancer cells using MTT assay and Annexin V-FITC respectively. The molecular pathways involved to such effects were further examined by evaluating its ability to inhibit (a) the NF-[kappa]B phosphorylation (S536), (b)JNK and Akt phosphorylation (Thrl 83/Tyrl 85 and S473 respectively) and (c) IL-6 production, using ELISA method. The anti-microbial effects of the trihydroxy ketone against a panel of nine pathogenic bacteria and three fungi were also assessed.
The trihydroxy ketone exerted significant apoptotic activity in PC-3 prostate cancer cells at 100 [micro]M, while it inhibited NF-[kappa]B phosphorylation and IL-6 secretion at a concentration range [10.sup.-6]-[10.sup.-4] M. Akt and JNK signaling were not found to participate in this process. The trihydroxy ketone exerted significant anti-microbial profile against many human pathogenic bacteria and fungi (MIC values ranged from 0.04 to 0.57 mg/ml). Conclusively, the Greek thyme honey-derived monoterpene exerted significant apoptotic activity in PC-3 cells, mediated, at least in part, through reduction of NF-[kappa]B activity and IL-6 secretion and may play a key role in the anti-growth effect of thyme honey on prostate cancer cells.
A Dietary Tomato Supplement Prevents Prostate Cancer in TRAMP Mice Tania Pannellini1,3, Manuela Iezzi1,3, Marcella Liberatore1,3, Federica Sabatini1,3, Stefano Iacobelli1,3, Cosmo Rossi3, Saverio Alberti3, Carmine Di Ilio2,3, Paola Vitaglione4, Vincenzo Fogliano4, and Mauro Piantelli1,3
Manuela Iezzi, Department of Oncology and Neurosciences and CeSI Foundation, University “G. d' Annunzio,” 66013 Chieti, Italy
Abstract Transgenic adenocarcinoma of the mouse prostate (TRAMP) is a model for progressive prostate cancer that mirrors the stages of the human form. In this study, the effects of a diet enriched with processed whole tomatoes on survival, tumorigenesis, and progression of prostate cancer, and the antioxidant and inflammatory status of TRAMP mice were investigated. Tomato diet significantly increased overall survival (P < 0.01), delayed progression from prostatic intraepithelial neoplasia to adenocarcinoma, and decreased the incidence of poorly differentiated carcinoma. Biochemical data disclosed an increase in serum antioxidant activity and a reduction of serum inflammation/angiogenesis biomarkers of particular importance in prostate carcinogenesis.
Conclusion Daily consumption of a tomato-rich diet was highly effective in preventing prostate cancer in TRAMP mice .In addition to its direct effects on tumor cells, tomato, a functional food containing a mixture of pleiotropic com-pounds (47), can be regarded as a biological response modifier whose establishment of an anti-inflammatory and antiangiogenic environment prevents tumor onset and progression
Pomegranate Juice Metabolites, Ellagic Acid and Urolithin A, Synergistically Inhibit Androgen Independent Prostate Cancer Cell Growth via Distinct Effects on Cell Cycle Control and Apoptosis Roberto Vicinanza1, Yanjun Zhang1, Susanne M.Henning1 and David Heber1§ 1Center for Human Nutrition, David Geffen School of Medicine, University of California, Los Angeles, California, UCLA.
Abstract Ellagitannins (ET) from pomegranate juice (PJ) are bioactive polyphenols with chemopreventive potential against prostate cancer (PCa). ET are not absorbed intact, but are partially hydrolyzed in the gut to ellagic acid (EA). Colonic microflora can convert EA to urolithin A (UA), and EA and UA enter the circulation after PJ consumption. Here, we studied the effects of EA and UA on cell proliferation, cell cycle and apoptosis in DU-145 and PC-3 androgen-independent PCa cells, and whether combinations of EA and UA affected cell proliferation. EA demonstrated greater dose-dependent antiproliferative effects in both cell lines compared to UA. EA induced cell cycle arrest in S-phase associated with decreased cyclin B1 and cyclin D1 levels. UA induced a G2/M arrest and increased cyclin B1 and cdc2 phosphorylation at tyrosine-15, suggesting inactivation of the cyclin B1/cdc2 kinase complex. EA induced apoptosis in both cell lines, while UA had a less pronounced pro-apoptotic effect only in DU- 145. Co-treatment with low concentrations of EA and UA dramatically decreased cell proliferation, exhibiting synergism in PC-3 cells evaluated by isobolographic analysis and combination index. These data provide information on pomegranate metabolites for the prevention PCa recurrence, supporting the role of gut flora-derived metabolites for cancer prevention.
20(S)-25-methoxyl-dammarane-3β, 12β, 20-triol, a novel natural product for prostate cancer therapy: activity in vitro and in vivo and mechanisms of action W Wang1,4, H Wang2,4, E R Rayburn1, Y Zhao1,3, D L Hill1 and R Zhang1
1Department of Pharmacology and Toxicology, Division of Clinical Pharmacology, and Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham AL 35294, USA
2Institute for Nutritional Sciences, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PR China
3Shenyang Pharmaceutical University, Shenyang 110016, PR China
Abstract We recently isolated 20(S)-25-methoxyl-dammarane-3β, 12β, 20-triol (25-OCH3-PPD), a natural product from Panax notoginseng, and demonstrated its cytotoxicity against a variety of cancer cells. Here we report the effects of this compound in vitro and in vivo on human prostate cancer cells, LNCaP (androgen-dependent) and PC3 (androgen-independent), in comparison with three structurally related ginsenosides, ginsenoside Rh2, ginsenoside Rg3, and 20(S)-protopanaxadiol. Of the four test compounds, 25-OCH3-PPD was most potent. It decreased survival, inhibited proliferation, induced apoptosis, and led to G1 cell cycle arrest in both cell lines. It also decreased the levels of proteins associated with cell proliferation (MDM2, E2F1, cyclin D1, and cdks 2 and 4) and increased or activated pro-apoptotic proteins (cleaved PARP, cleaved caspase-3, -8, and -9). In LNCaP cells, 25-OCH3-PPD inhibited the expression of the androgen receptor and prostate-specific antigen. Moreover, 25-OCH3-PPD inhibited the growth of prostate cancer xenograft tumours. Combining 25-OCH3-PPD with conventional chemotherapeutic agents or with radiation led to potent antitumour effects; tumour regression was almost complete following administration of 25-OCH3-PPD and either taxotere or gemcitabine. 25-OCH3-PPD also demonstrated low toxicity to noncancer cells and no observable toxicity in animals. In conclusion, our preclinical data indicate that 25-OCH3-PPD is a potential therapeutic agent against both androgen-dependent and androgen-independent prostate cancer.
....Although the four ginsenosides share a common core structure, they have remarkably different effects on cancer cells. Of those tested, 25-OCH3-PPD demonstrated the most potent cytotoxic, antiproliferative, pro-apoptotic, and cell cycle regulatory effects. Moreover, it produced strong antitumour effects against a model of androgen-independent prostate cancer both alone and in combination with conventional cancer therapies. These results indicate that 25-OCH3-PPD may be an appropriate candidate for further preclinical and clinical development as an antiprostate cancer agent either alone or in combination with conventional therapies.
Validation of the Antiproliferative Effects of Organic Extracts from the Green Husk of Juglans regia L. on PC-3 Human Prostate Cancer Cells by Assessment of Apoptosis-Related Genes Ali A. Alshatwi,* Tarique N. Hasan, Gowhar Shafi, Naveed Ahmed Syed, Abdullah H. Al-Assaf, Mohammed S. Alamri, and Abdrohman S. Al-Khalifa
Abstract With the increased use of plant-based cancer chemotherapy, exploring the antiproliferative effects of phytochemicals for anticancer drug design has gained considerable attention worldwide. This study was undertaken to investigate the effect of walnut green husk extracts on cell proliferation and to determine the possible molecular mechanism of extract-induced cell death by quantifying the expression of Bcl-2, Bax, caspases-3, and Tp53. PC-3 human prostate cancer cells. In this study, we found that green husk extracts suppressed proliferation and induced apoptosis in a dose- and time-dependent manner by modulating expression of apoptosis-related genes. This involved DNA fragmentation (determined by TUNEL assay) and significant changes in levels of mRNA and the expression of corresponding proteins. An increase in expressions of Bax, caspase-3, and tp53 genes and their corresponding proteins was detected using real-time PCR and western blot analysis in PC-3 cells treated with the green husk organic extracts. In contrast, Bcl2 expression was downregulated after exposure to the extracts. Our data suggest the presence of bioactive compound(s) in walnut green husks that are capable of killing prostate carcinoma cells by inducing apoptosis and that the husks are a candidate source of anticancer drugs.
Source : Evid Based Complement Alternat Med. 2012; 2012: 103026. doi: 10.1155/2012/103026 Link to Full Article
Effects of Homeopathic Preparations on Human Prostate Cancer Growth in Cellular and Animal Models
Brian W. MacLaughlin, BS
Department of Physiology and Biophysics, Georgetown University Medical Center, Washington, DC
Babett Gutsmuths, PharmD, PhD
Ewald Pretner, MD
Department of Cell Biology, Georgetown University Medical Center, Washington, DC
Wayne B. Jonas, MD
John Ives, PhD
Samueli Institute for Information Biology, Alexandria, VA
Don Victor Kulawardane, MD, DTH, DCH
Homeopathic Clinic, Jayawardane Place, Dehiwala, Sri Lanka
Hakima Amri, PhD
Department of Physiology and Biophysics, Basic Science Building, room 217, Georgetown University Medical Center, 3900 Reservoir Rd, NW, Washington, DC 20007 email@example.com.
Abstract The use of dietary supplements for various ailments enjoys unprecedented popularity. As part of this trend, Sabal serrulata (saw palmetto) constitutes the complementary treatment of choice with regard to prostate health. In homeopathy, Sabal serrulata is commonly prescribed for prostate problems ranging from benign prostatic hyperplasia to prostate cancer. The authors' work assessed the antiproliferative effects of homeopathic preparations of Sabal serrulata, Thuja occidentalis, and Conium maculatum, in vivo, on nude mouse xenografts, and in vitro, on PC-3 and DU-145 human prostate cancer as well as MDA-MB-231 human breast cancer cell lines. Treatment with Sabal serrulata in vitro resulted in a 33% decrease of PC-3 cell proliferation at 72 hours and a 23% reduction of DU-145 cell proliferation at 24 hours (P<.01). The difference in reduction is likely due to the specific doubling time of each cell line. No effect was observed on MDA-MB-231 human breast cancer cells. Thuja occidentalis and Conium maculatum did not have any effect on human prostate cancer cell proliferation. In vivo, prostate tumor xenograft size was significantly reduced in Sabal serrulata–treated mice compared to untreated controls (P=.012). No effect was observed on breast tumor growth. Our study clearly demonstrates a biologic response to homeopathic treatment as manifested by cell proliferation and tumor growth. This biologic effect was (i)significantly stronger to Sabal serrulata than to controls and (ii)specific to human prostate cancer. Sabal serrulata should thus be further investigated as a specific homeopathic remedy for prostate pathology.
Pomegranate extract induces apoptosis in human prostate cancer cells by modulation of the IGF-IGFBP axis Satomi Koyama,1 Laura J Cobb,1 Hemal H Mehta,1 Navindra P. Seeram,2 David Heber,2 Allan J. Pantuck,3 and Pinchas Cohen11
Division of Pediatric Endocrinology, Mattel Children's Hospital, David Geffen School of Medicine, University of California, Los Angeles 2Center for Human Nutrition, David Geffen School of Medicine, UCLA 3 Department of Urology, David Geffen School of Medicine, UCLA
Abstract The IGF axis is critical for the regulation of apoptosis in many human cancer cell lines. Recently, potent anti-tumorigenic effects of pomegranate juice and extracts have been reported. Consequently, pomegranate has potential not only as a treatment but also as a preventative measure against certain types of cancer, including prostate. In this study, we investigated the relationship between pomegranate-induced apoptosis in human prostate cancer cells and the IGF/IGFBP system. Treatment of LAPC4 prostate cancer cells with 10 μg/ml POMx, a highly potent pomegranate extract prepared from skin and arils minus seeds and standardized to ellagitannin content (37% punicalagins by HPLC), resulted in inhibition of cell proliferation and induction of apoptosis. Interestingly, co-treatment with POMx and IGFBP-3 revealed synergistic stimulation of apoptosis and additive inhibition of cell growth. Western blot analysis revealed that treatment with POMx or POMx/IGFBP-3 combination resulted in increased JNK phosphorylation, and decreased Akt and mTOR activation, consistent with a growth inhibitory, pro-apoptotic function. We also investigated the relationship between IGF-1 and pomegranate-induced apoptosis in 22RV1 prostate cancer cells. Co-treatment with 100 ng/ml IGF-1 completely blocked apoptosis induction by POMx. In contrast, IGF-I failed to inhibit POMx-induced apoptosis in R- cells, suggesting the importance of IGF-IR. POMx-treatment decreased Igf1 mRNA expression in a dose-dependent manner indicating that its actions also involve tumor-specific suppression of IGF-1. These studies revealed novel interactions between the IGF system and pomegranate-induced apoptosis.
In conclusion, these studies reveal novel interactions between the IGF system and pomegranate-induced apoptosis, and suggest that pomegranate products modulate the tumor production and responsiveness to IGFs and the IGFBPs. As IGFBP-3 is currently being tested in humans as a treatment for prostate cancer and pomegranate supplements are becoming popular as adjuvant nutritional treatments for this disease, we propose that these agents may emerge as useful in the management of prostate cancer.
Pomegranate extract inhibits androgen-independent prostate cancer growth through a nuclear factor-κB-dependent mechanism Matthew B. Rettig 25,David Heber4, Jiabin An5,Navindra P. Seeram4,Jian Y. Rao3, Huiren Liu1,Tobias Klatte2,Arie Belldegrun2,Aune Moro4,Susanne M. Henning4, Deqiong Mo5,William J. Aronson26 and Allan Pantuck2
Abstract Constitutive nuclear factor-κB (NF-κB) activation is observed in androgen-independent prostate cancer and represents a predictor for biochemical recurrence after radical prostatectomy. Dietary agents such as pomegranate extract (PE) have received increasing attention as potential agents to prevent the onset or progression of many malignancies, including prostate cancer. Here, we show that PE inhibited NF-κB and cell viability of prostate cancer cell lines in a dose-dependent fashion in vitro. Importantly, maximal PE-induced apoptosis was dependent on PE-mediated NF-κB blockade. In the LAPC4 xenograft model, PE delayed the emergence of LAPC4 androgen-independent xenografts in castrated mice through an inhibition of proliferation and induction of apoptosis. Moreover, the observed increase in NF-κB activity during the transition from androgen dependence to androgen independence in the LAPC4 xenograft model was abrogated by PE. Our study represents the first description of PE as a promising dietary agent for the prevention of the emergence of androgen independence that is driven in part by heightened NF-κB activity.
.....Extending the duration of the androgen-dependent state could potentially prolong life expectancy of prostate cancer patients and delay or prevent the need for additional hormonal therapy or chemotherapy. In this regard, our finding that PE delayed the growth and emergence of androgen independence in our xenograft model may be particularly germane. Of importance, our group showed previously that dietary fat reduction delayed the emergence of androgen independence and prolonged survival using a similar xenograft model (36). Future research will focus on potential additive and/or synergistic effects of combining a low-fat diet with PE. Based on our results, we propose that PJ could have potential as a dietary agent to prevent the emergence of androgen independence and suggest that this may be a high priority area for future clinical investigation.
Multitargeted therapy of cancer by lycopene Richard B. van Breemen and Natasa Pajkovic
Department of Medicinal Chemistry and Pharmacognosy, University of Illinois College of Pharmacy, 833 S. Wood St., Chicago, IL 60612, USA
Abstract An acyclic, non-provitamin A carotene, lycopene is responsible for the red pigmentation of ripe tomatoes and some other edible fruits such as watermelon and papaya. Lycopene is also a potent antioxidant and scavenger of free radicals. Multiple retrospective and prospective epidemiological studies have indicated that the consumption of tomato products containing lycopene is associated with a reduced risk of prostate cancer. These epidemiological studies are supported by numerous in vitro assays using cell cultures that show anti-cancer activities and cancer chemoprevention activities of lycopene in many cell lines including prostate cancer cells. These activities include inducing apoptosis, inhibiting metastasis, preventing oxidative stress, and up-regulating the antioxidant response element so that cells can produce cytoprotective enzymes against prooxidants and electrophiles. In vivo animal studies and Phase I and II clinical trials have shown that lycopene supplements are non-toxic and that lycopene is orally bioavailable. Furthermore, lycopene is concentrated in prostate tissue and localized to the nucleus. In addition, some oxygenated metabolites of lycopene have been identified, and might be active as chemoprevention agents. The next phase of research concerning lycopene as a chemoprevention agent will be Phase II clinical trials of efficacy that are placebo-controlled, randomized and double blind. These clinical trials are required to establish the efficacy of lycopene supplementation.
The Aqueous Soluble Polyphenolic Fraction of Psidium guajava Leaves Exhibits Potent Anti-Angiogenesis and Anti-Migration Actions on DU145 Cells
Chiung-Chi Peng,1,2 Chiung-Huei Peng,3,4 Kuan-Chou Chen,5 Chiu-Lan Hsieh,6 and Robert Y. Peng4 1School of Physical Therapy, College of Health Care, China Medical University, 91, Hsueh-Shih Rd., Taichung, Taiwan 40202, Taiwan 2Graduate Institute of Rehabilitation Science, College of Health Care, China Medical University, 91, Hsueh-Shih Rd., Taichung, Taiwan 40202, Taiwan 3Department of Nursing, Hungkuang University, 34, Chung-Chi Rd., Shalu County, Taichung Hsien, Taiwan 43302, Taiwan 4Research Institute of Biotechnology, Hungkuang University, 34, Chung-Chi Rd., Shalu County, Taichung Hsien, Taiwan 43302, Taiwan 5Department of Urology, Taipei Medical University-Shuang Ho Hospital, Taipei Medical University, 250, Wu-Xin St., Xin-Yi District, Taipei, Taiwan 6Graduate Institute of Biotechnology, National Chang-Hua University of Education, 1, Jin-De Road, Changhua City 500, Taiwan
Abstract The aqueous extract of Psidium guajava budding leaves (PE) bears an extremely high content of polyphenolic and isoflavonoids. Whether it could be used as an anti-tumor chemopreventive in view of anti-angiogenesis and anti-migration, we performed the assay methods including the MTT assay to examine the cell viability; the ELISA assay to test the expressions of VEGF, IL-6 and IL-8; the western blot 1 analysis to detect TIMP-2; the gelatinolytic zymography to follow the expression of MMPs; the wound scratch assay to examine the migration capability; and the chicken chorioallantoic membrane assay to detect the suppressive angiogenesis. Results indicated that the IC50 of PE for 5 cells was ~0.57 mg ml−1. In addition, PE effectively inhibited the expressions of VEGF, IL-6 and IL-8 cytokines, and MMP-2 and MMP-9, and simultaneously activated TIMP-2 and suppressed the cell migration and the angiogenesis. Conclusively, PE potentially possesses a strong anti-DU145 effect. Thus, clinically it owns the potential to be used as an effective adjuvant anti-cancer chemopreventive. .......We conclude that PE potentially possesses a strong anti-prostate cancer effect. Results suggest that PE can be used as an effective clinical adjuvant anti-prostate cancer chemopreventive.
Curcumin sensitizes TRAIL-resistant xenografts: molecular mechanisms of apoptosis, metastasis and angiogenesis Sharmila Shankar, Suthakar Ganapathy, Qinghe Chen and Rakesh K Srivastava
Abstract Background We have recently shown that curcumin (a diferuloylmethane, the yellow pigment in turmeric) enhances apoptosis-inducing potential of TRAIL in prostate cancer PC-3 cells, and sensitizes TRAIL-resistant LNCaP cells in vitro through multiple mechanisms. The objectives of this study were to investigate the molecular mechanisms by which curcumin sensitized TRAIL-resistant LNCaP xenografts in vivo.
Methods Prostate cancer TRAIL-resistant LNCaP cells were implanted in Balb c nude mice to examine the effects of curcumin and/or TRAIL on tumor growth and genes related to apoptosis, metastasis and angiogenesis.
Results Curcumin inhibited growth of LNCaP xenografts in nude mice by inducing apoptosis (TUNEL staining) and inhibiting proliferation (PCNA and Ki67 staining), and sensitized these tumors to undergo apoptosis by TRAIL. In xenogrfated tumors, curcumin upregulated the expression of TRAIL-R1/DR4, TRAIL-R2/DR5, Bax, Bak, p21/WAF1, and p27/KIP1, and inhibited the activation of NFκB and its gene products such as cyclin D1, VEGF, uPA, MMP-2, MMP-9, Bcl-2 and Bcl-XL. The regulation of death receptors and members of Bcl-2 family, and inactivation of NFκB may sensitize TRAIL-resistant LNCaP xenografts. Curcumin also inhibited number of blood vessels in tumors, and circulating endothelial growth factor receptor 2-positive endothelial cells in mice.
Conclusion The ability of curcumin to inhibit tumor growth, metastasis and angiogenesis, and enhance the therapeutic potential of TRAIL suggests that curcumin alone or in combination with TRAIL can be used for prostate cancer prevention and/or therapy.
Anticancer activity of a sub-fraction of dichloromethane extract of Strobilanthes crispus on human breast and prostate cancer cells in vitro Nik Soriani Yaacob,1 Nurraihana Hamzah,2 Nik Nursyazni Nik Mohamed Kamal,1 Siti Amalina Zainal Abidin,1 Choon Sheen Lai,2 Visweswaran Navaratnam,2 and Mohd Nor Norazmi3
1Department of Chemical Pathology, School of Medical Sciences, Universiti Sains Malaysia Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia 2Centre for Drug Research, Universiti Sains Malaysia, 11800 Minden, Pulau Pinang, Malaysia 3School of Health Sciences, Universiti Sains Malaysia Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
Background The leaves of Strobilanthes crispus (S. crispus) which is native to the regions of Madagascar to the Malay Archipelago, are used in folk medicine for their antidiabetic, diuretic, anticancer and blood pressure lowering properties. Crude extracts of this plant have been found to be cytotoxic to human cancer cell lines and protective against chemically-induced hepatocarcinogenesis in rats. In this study, the cytotoxicity of various sub-fractions of dichloromethane extract isolated from the leaves of S. crispus was determined and the anticancer activity of one of the bioactive sub-fractions, SC/D-F9, was further analysed in breast and prostate cancer cell lines.
Methods The dichloromethane extract of S. crispus was chromatographed on silica gel by flash column chromatography. The ability of the various sub-fractions obtained to induce cell death of MCF-7, MDA-MB-231, PC-3 and DU-145 cell lines was determined using the LDH assay. The dose-response effect and the EC50 values of the active sub-fraction, SC/D-F9, were determined. Apoptosis was detected using Annexin V antibody and propidium iodide staining and analysed by fluorescence microscopy and flow cytometry, while caspase 3/7 activity was detected using FLICA caspase inhibitor and analysed by fluorescence microscopy.
Results Selected sub-fractions of the dichloromethane extract induced death of MCF-7, MDA-MB-231, PC-3 and DU-145 cells. The sub-fraction SC/D-F9, consistently killed breast and prostate cancer cell lines with low EC50 values but is non-cytotoxic to the normal breast epithelial cell line, MCF-10A. SC/D-F9 displayed relatively higher cytotoxicity compared to tamoxifen, paclitaxel, docetaxel and doxorubicin. Cell death induced by SC/D-F9 occurred via apoptosis with the involvement of caspase 3 and/or 7
Conclusions A dichloromethane sub-fraction of S. crispus displayed potent anticancer activities in vitro that can be further exploited for the development of a potential therapeutic anticancer agent.
Chemopreventive potential of curcumin in prostate cancer Marie-Hélène Teiten, François Gaascht, Serge Eifes, Mario Dicato, and Marc DiederichLaboratoire de Biologie Moléculaire et Cellulaire du Cancer, Hôpital Kirchberg, 9 rue Edward Steichen, 2540 Luxembourg, Luxembourg
Abstract The long latency and high incidence of prostate carcinogenesis provides the opportunity to intervene with chemoprevention in order to prevent or eradicate prostate malignancies. We present here an overview of the chemopreventive potential of curcumin (diferuloylmethane), a well-known natural compound that exhibits therapeutic promise for prostate cancer. In fact, it interferes with prostate cancer proliferation and metastasis development through the down-regulation of androgen receptor and epidermal growth factor receptor, but also through the induction of cell cycle arrest. It regulates the inflammatory response through the inhibition of pro-inflammatory mediators and the NF-κB signaling pathway. These results are consistent with this compound’s ability to up-induce pro-apoptotic proteins and to down-regulate the anti-apoptotic counterparts. Alone or in combination with TRAIL-mediated immunotherapy or radiotherapy, curcumin is also reported to be a good inducer of prostate cancer cell death by apoptosis. Curcumin appears thus as a non-toxic alternative for prostate cancer prevention, treatment or co-treatment.
Genomic Analysis Highlights the Role of the JAK-STAT Signaling in the Anti-proliferative Effects of Dietary Flavonoid—‘Ashwagandha’ in Prostate Cancer Cells Ravikumar Aalinkeel1, Zihua Hu2, Bindukumar B. Nair1, Donald E. Sykes1, Jessica L. Reynolds1, Supriya D. Mahajan1 and Stanley A. Schwartz1
1Department of Medicine, Division of Allergy, Immunology, and Rheumatology, Buffalo General Hospital, Kaleida Health System and 2Center for Computational Research, New York State Center of Excellence in Bioinformatics and Life Sciences and Department of Biostatistics, University at Buffalo, State University of New York (SUNY), New York State Center of Excellence, Buffalo, NY 14203, USA
aBSTRACT Phytochemicals are dietary phytoestrogens that may play a rolein prostate cancer prevention. Forty percent of Americans usecomplementary and alternative medicines (CAM) for disease preventionand therapy. Ashwagandha (Withania somnifera) contains flavonoidsand active ingredients like alkaloids and steroidal lactoneswhich are called ‘Withanolides’. We hypothesizethat the immunomodulatory and anti-inflammatory properties ofAshwagandha might contribute to its overall effectiveness asan anti-carcinogenic agent. The goal of our study was gain insightinto the general biological and molecular functions and immunomodulatoryprocesses that are altered as a result of Ashwagandha treatmentin prostate cancer cells, and to identify the key signalingmechanisms that are involved in the regulation of these physiologicaleffects using genomic microarray analysis in conjunction withquantitative real-time PCR and western blot analysis. Ashwagandhatreatment significantly downregulated the gene and protein expressionof proinflammatory cytokines IL-6, IL-1β, chemokine IL-8,Hsp70 and STAT-2, while a reciprocal upregulation was observedin gene and protein expression of p38 MAPK, PI3K, caspase 6,Cyclin D and c-myc. Furthermore, Ashwagandha treatment significantlymodulated the JAK-STAT pathway which regulates both the apoptosisprocess as well as the MAP kinase signaling. These studies outlineseveral functionally important classes of genes, which are associatedwith immune response, signal transduction, cell signaling, transcriptionalregulation, apoptosis and cell cycle regulation and provideinsight into the molecular signaling mechanisms that are modulatedby Ashwagandha, thereby highlighting the use of this bioflavanoidas effective chemopreventive agent relevant to prostate cancerprogression.
Abstract Purpose: We have shown previously that oral feeding of green tea polyphenols (GTP) to transgenic adenocarcinoma of the mouse prostate mice in a purely chemopreventive setting significantly inhibits prostate cancer development. To translate this to a human situation, the present study was designed to identify the stage of prostate cancer that is most vulnerable to chemopreventive intervention by GTP.
Experimental Design: GTP infusion (0.1% in drinking water) to transgenic adenocarcinoma of the mouse prostate was initiated at ages representing different stage of the disease: (a) 6 weeks (group 1, normal prostate), (b) 12 weeks (group 2, prostatic intraepithelial neoplasia), (c) 18 weeks (group 3, well-differentiated adenocarcinoma), and (b) 28 weeks (group 4, moderately differentiated adenocarcinoma). At age 32 weeks, subsets of animals were evaluated by magnetic resonance imaging, ultrasound, and prostate weight and for serum insulin-like growth factor (IGF)-I/IGF binding protein-3 and IGF signaling.
Results: Tumor-free survival was extended to 38 weeks (P < 0.001) in group 1, 31 weeks (P < 0.01) in group 2, and 24 weeks (P < 0.05) in group 3 compared with 19 weeks in water-fed controls. Median life expectancy was 68 weeks in group 1, 63 weeks in group 2, 56 weeks in group 3, and 51 weeks in group 4 compared with 42 weeks in the control mice. IGF-I and its downstream targets including phosphatidylinositol 3-kinase, pAkt, and phosphorylated extracellular signal-regulated kinase were significantly inhibited only when intervention was initiated early when prostatic intraepithelial neoplasia lesions were common.
Conclusions: Our studies indicate that chemopreventive potential of GTP decreases with advancing stage of the disease and underscore the need to design appropriate chemoprevention clinical trails.
NOTE Among all cancers, prostate cancer is an ideal candidate disease for chemoprevention because it is typically diagnosed in men ages >50 years and has a high latency period (1, 2). Therefore, even a slight delay in the progression of this disease by chemopreventive intervention could result in a substantial reduction in the incidence of the disease and, more importantly, improve the quality of life of the patients (1, 2). Evidences collected from geographic, epidemiologic, and migration studies suggest that frequent consumption of green tea is associated with lower frequencies of prostate cancer in Asian population in general compared with those in western societies (3–7). Laboratory and preclinical animal studies also indicate a protective role of green tea against prostate cancer (reviewed in refs. 8–12).
We have shown previously that oral infusion of a decaffeinated polyphenolic fraction isolated from green tea at a human achievable dose (equivalent to 6 cups of green tea a day) beginning at age 8 weeks significantly inhibits prostate cancer development, progression, and its metastasis and enhances tumor-free and overall survival in the transgenic adenocarcinoma of the mouse prostate (TRAMP) mice (13–15). Initial clinical trials of green tea polyphenols (GTP) involving human prostate cancer patients have produced mixed results. Choan et al. (16) evaluated the efficacy and toxicity of green tea on hormone-refractory prostate cancer. Patients with hormone-refractory prostate cancer were prescribed green tea extract capsules at a dose level of 250 mg twice daily. Although treatment was generally well tolerated, 9 of 15 patients had progressive disease within 2 months of starting therapy and 6 patients developed progressive disease after additional 1 to 4 months of therapy. The study concluded that green tea had minimal clinical activity against hormone-refractory prostate cancer. A phase II trial explored the antineoplastic effects of green tea's (6 g/d green tea, orally in 6 divided doses) in 42 patients with hormone-refractory prostate cancer (17). Tumor response, defined as a decline (≥50%) in the baseline prostate-specific antigen value, occurred in only 2% of the cohort (95% confidence interval, 1-14%), which was not sustained beyond 2 months. The study suggested that green tea carries limited antineoplastic activity, as defined by a decline in prostate-specific antigen levels, among patients with hormone-refractory prostate cancer (17).
A recent proof-of-principle clinical trial assessed the safety and efficacy of green tea consumption in volunteers with high-grade prostatic intraepithelial neoplasia (HGPIN; ref. 18). Tumor incidence was significantly lower in green tea-treated men compared with placebo-treated men. A 2-year follow-up of patients from the same study indicated that green tea effects were long-lasting (19). This study brought into focus the importance of early intervention with green tea and highlighted the significance of green tea in a purely chemopreventive setting.
We hypothesized that green tea feeding is more effective at early stages of prostate cancer development than at the later stages. This study, therefore, was designed to assess the effectiveness of oral feeding of GTP at defined stages of prostate cancer development and progression in the autochthonous transgenic TRAMP model. Alternatively, this preclinical study was intended to assess the appropriateness of the stage of prostate cancer patients that could benefit from green tea consumption.
Multi-targeted Therapy of Cancer by Omega-3 Fatty Acids
Isabelle M. Berquin1,2, Iris J. Edwards2, and Yong Q. Chen1* 1Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina. 2Department of Pathology, Wake Forest University School of Medicine, Winston-Salem, North Carolina.
Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) are essential fatty acids necessary for human health. Currently, the Western diet contains a disproportionally high amount of n-6 PUFAs and low amount of n-3 PUFAs, and the resulting high n-6/n-3 ratio is thought to contribute to cardiovascular disease, inflammation, and cancer. Studies in human populations have linked high consumption of fish or fish oil to reduced risk of colon, prostate and breast cancer, although other studies failed to find a significant association. Nonetheless, the available epidemiological evidence, combined with the demonstrated effects of n-3 PUFAs on cancer in animal and cell culture models, has motivated the development of clinical interventions using n-3 PUFAs in the prevention and treatment of cancer, as well as for nutritional support of cancer patients to reduce weight loss and modulate the immune system. In this review, we discuss the rationale for using long-chain n-3 PUFAs in cancer prevention and treatment and the challenges that such approaches pose in the design of clinical trials.
Source Cancer Lett. 2008 October 8; 269(2): 363–377. doi:10.1016/j.canlet.2008.03.044 LINK TO FULL ARTICLE
RRR-α-Vitamin E Succinate Potentiates the Antitumor Effect of Calcitriol in Prostate Cancer without Overt Side Effects
Abstract Purpose: To determine the antitumor efficacy of using calcitriol combined with RRR-α-vitamin E succinate (VES) on prostate cancer.
Experimental Design: The effects of VES or VES in combination with calcitriol on the calcitriol target genes were evaluated by Western blot and real-time PCR. The antiproliferation effect of the combination in prostate cancer cells was evaluated by the combination index method. The role of the vitamin D3 receptor (VDR) in the enhanced antitumor effects of the combination was confirmed by small interfering RNA knockdown strategy. Xenograft-bearing mice were used to reaffirm the antitumor efficacy of this combination. Pathohistology analyses and expressions of VDR and its target genes were analyzed in untreated and treated tumors.
Results: VES selectively increased VDR protein in different prostate cancer cells. Low doses of calcitriol combined with VES were significantly superior to the additive effect of individual treatments against prostate cancer cell proliferation. The expression of VDR target genes involved in antiproliferation were further sensitized in the presence of VES. Knockdown of VDR expression abolished the combination benefits in LNCaP and PC3 cells. Consistently, in prostate cancer xenograft models, VES enhanced the therapeutic efficacy of a tolerated dose of calcitriol yet without overt evidence of systemic toxicity and hypercalcemia. This notable in vivo effect was also accompanied by up-regulation of VDR target genes.
Conclusions: Low-dose calcitriol combined with vitamin E analogue could be a solution to the calcemic side effect. The demonstration of superior antitumor activity of low-dose calcitriol plus VES provides the preclinical basis for developing a useful therapeutic strategy for prostate cancer.
The dietary bioflavonoid quercetin synergizes with epigallocathechin gallate (EGCG) to inhibit prostate cancer stem cell characteristics, invasion, migration and epithelial-mesenchymal transition. Su-Ni Tang, Chandan Singh, Dara Nall, Daniel Meagher, Sharmila Shankar, and Rakesh K Srivastava
Background Much attention has been recently focused on the role of cancer stem cells (CSCs) in the initiation and progression of solid malignancies. Since CSCs are able to proliferate and self-renew extensively due to their ability to express anti-apoptotic and drug resistant proteins, thus sustaining tumor growth. Therefore, the strategy to eradicate CSCs might have significant clinical implications. The objectives of this study were to examine the molecular mechanisms by which epigallocathechin gallate (EGCG) inhibits stem cell characteristics of prostate CSCs, and synergizes with quercetin, a major polyphenol and flavonoid commonly detected in many fruits and vegetables.
Results Our data indicate that human prostate cancer cell lines contain a small population of CD44+CD133+ cancer stem cells and their self-renewal capacity is inhibited by EGCG. Furthermore, EGCG inhibits the self-renewal capacity of CD44+alpha2beta1+CD133+ CSCs isolated from human primary prostate tumors, as measured by spheroid formation in suspension. EGCG induces apoptosis by activating capase-3/7 and inhibiting the expression of Bcl-2, survivin and XIAP in CSCs. Furthermore, EGCG inhibits epithelial-mesenchymal transition by inhibiting the expression of vimentin, slug, snail and nuclear beta-catenin, and the activity of LEF-1/TCF responsive reporter, and also retards CSC's migration and invasion, suggesting the blockade of signaling involved in early metastasis. Interestingly, quercetin synergizes with EGCG in inhibiting the self-renewal properties of prostate CSCs, inducing apoptosis, and blocking CSC's migration and invasion. These data suggest that EGCG either alone or in combination with quercetin can eliminate cancer stem cell-characteristics.
Conclusion Since carcinogenesis is a complex process, combination of bioactive dietary agents with complementary activities will be beneficial for prostate cancer prevention and/or treatment.
1The Prevention Program, Barbara Ann Karmanos Cancer Institute, and Department of Pathology, School of Medicine, Wayne State University, Detroit, Michigan and 2Wuhan Botanical Garden, Chinese Academy of Science, Wuhan, People's Republic of China
Abstract Interest in the use of traditional medicines for cancer prevention and treatment is increasing. In vitro, in vivo, and clinical studies suggest the potential use of proteasome inhibitors as novel anticancer drugs. Celastrol, an active compound extracted from the root bark of the Chinese medicine “Thunder of God Vine” (Tripterygium wilfordii Hook F.), was used for years as a natural remedy for inflammatory conditions. Although Celastrol has been shown to induce leukemia cell apoptosis, the molecular target involved has not been identified. Furthermore, whether Celastrol has antitumor activity in vivo has never been conclusively shown. Here, we report, for the first time, that Celastrol potently and preferentially inhibits the chymotrypsin-like activity of a purified 20S proteasome (IC50 = 2.5 μmol/L) and human prostate cancer cellular 26S proteasome (at 1-5 μmol/L). Inhibition of the proteasome activity by Celastrol in PC-3 (androgen receptor- or AR-negative) or LNCaP (AR-positive) cells results in the accumulation of ubiquitinated proteins and three natural proteasome substrates (IκB-α, Bax, and p27), accompanied by suppression of AR protein expression (in LNCaP cells) and induction of apoptosis. Treatment of PC-3 tumor–bearing nude mice with Celastrol (1-3 mg/kg/d, i.p., 1-31 days) resulted in significant inhibition (65-93%) of the tumor growth. Multiple assays using the animal tumor tissue samples from both early and end time points showed in vivo inhibition of the proteasomal activity and induction of apoptosis after Celastrol treatment. Our results show that Celastrol is a natural proteasome inhibitor that has a great potential for cancer prevention and treatment.
Diagnosis of Localized, Screen-Detected, Prostate Cancer—Crisis or Opportunity? Siu-Long Yao, Grace L. Lu-Yao Affiliations of authors: Oncology Clinical Research, Merck Research Laboratories, Kenilworth, NJ (S-LY); Department of Medicine, Cancer Institute of New Jersey, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, New Brunswick, NJ (S-LY, GL-Y)
Perhaps more so than with almost any other common cancer over the past one or two decades, we have witnessed an extraordinary change in the presenting characteristics of men with prostate cancer. Whereas disease was often disseminated at diagnosis20 years ago, it is now often organ confined. Whereas disease was often evident, it is now frequently asymptomatic at diagnosis.There could be many explanations for this change over time,but prostate-specific antigen (PSA) testing is probably chief among them because many of these changes coincided so closely with the introduction and use of this test.
These vast changes in the presenting population raise the possibility that previous data that were collected during the pre-PSA era may not reflect contemporary reality and may thus limit the ability of health-care providers and their patients to make the most appropriate decisions regarding the optimal management of the disease. To address this challenge, Stattin et al. (1)report the results of a study that adds to the growing list of population-based studies (2) with data on long-term outcomes for patients diagnosed with localized disease in the contemporary PSA era. Compared with previous research, this population-based study was notable in that the authors were able to incorporate PSA and Gleason score data into their statistical models.
The authors found that among low-risk patients with localized prostate cancer (defined as clinical stage T1, Gleason score6, and PSA <10 ng/mL) in the surveillance group, 10-year prostate cancer mortality was 2.4% (1). These results were similar to those of a recent US study (2) that was based on 1992–2002data in men aged 65–69 years with T1 disease (ie, 2% prostatecancer mortality). Results from both of these studies were substantially better than the 10-year cancer mortalities of 15%–23%that were reported previously in studies (2) of patients diagnosedin the pre-PSA era, including the Scandinavian Prostate Cancer Group Study No. 4 randomized prostatectomy trial (ie, 12.5%in the prostatectomy arm and 17.9% in the control arm) (3).These high survival outcomes were also consistent with results(4) from the European Randomized Study of Screening for Prostate Cancer that showed that approximately 48 men had to undergo cancer treatment (eg, surgery or radiation therapy) to avert one death from prostate cancer.
Probably, the most remarkable finding from this study (1) and several previous studies (2,5), however, is the realization that survival in most (eg, Gleason 7 disease), but not all (eg,Gleason 8–10), patients with localized disease managed conservatively is now similar to that of age-matched control subjects. Thus, most of these men can be expected to live out their lives without being mortally affected by prostate cancer,and most of these men will likely face a new health obstacle,a competing cause of death.
Source: Journal of the National Cancer Institute Advance Access published online on June 18, 2010 JNCI Journal of the National Cancer Institute, doi:10.1093/jnci/djq219 LINK TO SOURCE
Sulforaphane inhibits histone deacetylase activity in BPH-1, LnCaP, and PC-3 prostate epithelial cells Melinda C. Myzak 1, Karin Hardin 2, Rong Wang 3, Roderick H. Dashwood 4, and Emily Ho 5 *
1 Linus Pauling Institute, Oregon State University, Corvallis, OR 97331; Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR 97331 2 Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97331 3 Linus Pauling Institute, Oregon State University, Corvallis, OR 97331 4 Linus Pauling Institute, Oregon State University, Corvallis, OR 97331; Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331 5 Linus Pauling Institute, Oregon State University, Corvallis, OR 97331; Department of Nutrition and Exercise Sciences, Oregon State University, Corvallis, OR 97331
Sulforaphane (SFN), an isothiocyanate first isolated from broccoli,exhibits chemopreventive properties in prostate cancer cellsthrough mechanisms that are poorly understood. We recently reportedon a novel mechanism of chemoprotection by SFN in human coloncancer cells, namely the inhibition of histone deacetylase (HDAC).Here, we show that addition of 15 µM SFN also inhibitedHDAC activity by 40%, 30% and 40% in BPH-1, LnCaP, and PC-3prostate epithelial cells, respectively. The inhibition of HDACwas accompanied by a 50-100% increase in acetylated histonesin all three prostate cell lines, and in BPH-1 cells treatedwith SFN there was enhanced interaction of acetylated histoneH4 with the promoter region of the P21 gene and the bax gene.A corresponding 1.5 to 2-fold increase was seen for p21Cip1/Waf1and Bax protein expression, consistent with previous studiesusing HDAC inhibitors such as trichostatin A. The downstreamevents included cell cycle arrest and activation of apoptosis,as evidenced by changes in cell cycle kinetics and inductionof multi-caspase activity. These findings provide new insightinto the mechanisms of SFN action in benign prostate hyperplasia,androgen-dependent prostate cancer, and androgen-independentprostate cancer cells, and they suggest a novel approach tochemoprotection and chemotherapy of prostate cancer throughthe inhibition of HDAC
In summary, the present investigation has established an association between inhibition of HDAC activity, increased histone acetylation on bax and P21 promoters, elevated bax RNA and protein expression, and concomitant increase in cell cycle arrest and apoptotic markers after SFN treatment (Figure 7). These results suggest that SFN may be effective against benign prostate hyperplasia, androgen-dependent prostate cancer and androgen-independent prostate cancer potentially through the inhibition of HDAC activity. The present work focused on p21 and Bax, which are well-established targets of HDAC inhibitors and key regulators of cell cycle kinetics and apoptosis, but additional targets of HDAC inhibition warrant further investigation. Collectively, the results suggest that, in addition to its well-recognized effects on Phase 2 pathways, an alterative mechanism by which SFN can modulate gene expression is through the inhibition of HDAC activity, leading to apoptosis induction in cancer cells. The convergence of multiple mechanisms has many advantages; the present results and published data clearly indicate that SFN should be useful both as a chemopreventive agent and as a chemotherapeutic agent in the prostate
Chalcones Enhance TRAIL-Induced Apoptosis in Prostate Cancer Cells Ewelina Szliszka 1, Zenon P. Czuba 1, Bogdan Mazur 1, Lukasz Sedek 2, Andrzej Paradysz 3 and Wojciech Krol 1,
1 Chair and Department of Microbiology and Immunology, Medical University of Silesia in Katowice, Jordana 19, 41 808 Zabrze, Poland; 2 Chair and Department of Pediatric Hematology and Oncology, Medical University of Silesia in Katowice, 3-go Maja 13, 41 800 Zabrze, Poland; 3 Chair and Department of Urology, Medical University of Silesia in Katowice, 3-go Maja 13, 41 800 Zabrze, Poland
Abstract: Chalcones exhibit chemopreventive and antitumor effects. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a naturally occurring anticancer agent that induces apoptosis in cancer cells and is not toxic to normal cells. We examined the cytotoxic and apoptotic effect of five chalcones in combination with TRAIL on prostate cancer cells. The cytotoxicity was evaluated by the MTT and LDH assays. The apoptosis was determined using flow cytometry with annexin V-FITC. Our study showed that all five tested chalcones: chalcone, licochalcone-A, isobavachalcone, xanthohumol, butein markedly augmented TRAIL-mediated apoptosis and cytotoxicity in prostate cancer cells and confirmed the significant role of chalcones in chemoprevention of prostate cancer.
Results and Discussion 2.1. Cytotoxic and Apoptotic Effects of Chalcones in Prostate Cancer Cells Recent epidemiological studies have confirmed the role of polyphenols in prevention of prostate cancer [11,26,27]. Chalcones are plant-derived polyphenols belonging to the flavonoid family and widely investigated in various therapeutic areas. The previous experimental studies suggested that these compounds exert in vitro chemopreventive activity [6–9]. Chalcones inhibit cell growth and induce apoptosis in prostate cancer cells [13–17]. Panduratin A, a chalcone isolated from Kaempferiapandurata, induces apoptosis and G2/M cell cycle arrest in androgen-independent prostate cancer cells PC3 and DU145 . Licochalcone A and isoliquiritigenin detected in Glycyrrhiza glabrainhibit proliferation and block cell cycle progression in the G2/M phase in PC3 and DU145 cells [15,16]. Xanthohumol identified in Humulus lupulus exhibited antiproliferative activities on PC3 and DU145 cells . We have demonstrated that treatment of LNCaP prostate cancer cells with chalcones inhibits cell proliferation by induced cytotoxicity and apoptosis.
Source Int. J. Mol. Sci. 2010, 11, 1-13; doi:10.3390/ijms11010001 LINK TO SOURCE
A Concentrated Aglycone Isoflavone Preparation (GCP) That Demonstrates Potent Anti-Prostate Cancer Activity In vitro and In vivo
1Department of Urology, College of Physicians and Surgeons and 2 Department of Biostatistics, School of Public Health, Columbia University Medical Center, New York, New York
Abstract Purpose: Isoflavones have anticancer activities, but naturally occurring isoflavones are predominantly glycosylated and poorly absorbed. Genistein combined polysaccharide (GCP; Amino Up Chemical Co., Sapporo, Japan), is a fermentation product of soy extract and basidiomycetes mycillae that is enriched in biologically active aglycone isoflavones. This study analyzes GCP in vitro and in vivo for potential utility as a prostate cancer chemopreventative agent.
Experimental Design: Androgen-sensitive LNCaP and androgen-independent PC-3 cells were grown with various concentrations of GCP. In vitro cell growth was analyzed by the WST-1 assay, and apoptosis was assessed by fluorescence-activated cell sorting and detection of poly(ADP-ribose) polymerase cleavage using Western blot techniques. Effects of GCP on expression of cell cycle-regulatory proteins p53 (LNCaP only), p21, and p27 and the protein kinase Akt were considered using Western blot techniques. An in vivo LNCaP xenograft model was used to study the effects of a 2% GCP-supplemented diet on tumor growth in comparison with a control diet.
Results: GCP significantly suppressed LNCaP and PC-3 cell growth over 72 h (89% and 78% in LNCaP and PC-3, respectively, at 10 μg/ml; P < 0.0001). This reduction was associated with apoptosis in LNCaP cells, but not in PC-3 cells. GCP induced p27 and p53 (LNCaP only) protein expression within 6 h and suppressed phosphorylated Akt in both cell lines. The 2% GCP-supplemented diet significantly slowed LNCaP tumor growth, increasing apoptosis (P < 0.001), and decreasing proliferation (P < 0.001) over 4 weeks.
Conclusions: GCP has potent growth-inhibitory effects against prostate cancer cell lines in vitro and in vivo. These data suggest GCP has potential as an effective chemopreventive agent against prostate cancer cell growth.
Abstract Purpose:Wedelia chinensis is a common ingredient of anti-inflammatory herbal medicines in Taiwan and southern China. Inflammation is involved in promoting tumor growth, invasion, and metastasis. This study aims to test the biological effects in vivo of W. chinensis extract on prostate cancer.
Experimental Design: The in vivo efficacy and mechanisms of action of oral administration of a standardized extract of W. chinensis were analyzed in animals bearing a subcutaneous or orthotopic prostate cancer xenograft.
Results: Exposure of prostate cancer cells to W. chinensis extract induced apoptosis selectively in androgen receptor (AR)–positive prostate cancer cells and shifted the proportion in each phase of cell cycle toward G2-M phase in AR-negative prostate cancer cells. Oral herbal extract (4 or 40 mg/kg/d for 24-28 days) attenuated the growth of prostate tumors in nude mice implanted at both subcutaneous (31% and 44%, respectively) and orthotopic (49% and 49%, respectively) sites. The tumor suppression effects were associated with increased apoptosis and lower proliferation in tumor cells as well as reduced tumor angiogenesis. The antitumor effect of W. chinensis extract was correlated with accumulation of the principle active compounds wedelolactone, luteolin, and apigenin in vivo.
Conclusion: Anticancer action of W. chinensis extract was due to three active compounds that inhibit the AR signaling pathway. Oral administration of W. chinensis extract impeded prostate cancer tumorigenesis. Future studies of W. chinensis for chemoprevention or complementary medicine against prostate cancer in humans are thus warranted.
Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg Katharina Nimptsch, Sabine Rohrmann, and Jakob Linseisen
ABSTRACT Background: Anticarcinogenic activities of vitamin K have been observed in various cancer cell lines, including prostate cancer cells. Epidemiologic studies linking dietary intake of vitamin K with the development of prostate cancer have not yet been conducted.
Objective: We evaluated the association between dietary intake of phylloquinone (vitamin K1) and menaquinones (vitamin K2) and total and advanced prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition.
Design: At baseline, habitual dietary intake was assessed by means of a food-frequency questionnaire. Dietary intake of phylloquinone and menaquinones (MK-4–14) was estimated by using previously published HPLC-based food-content data. Multivariate-adjusted relative risks of total and advanced prostate cancer in relation to intakes of phylloquinone and menaquinones were calculated in 11 319 men by means of Cox proportional hazards regression.
Results: During a mean follow-up time of 8.6 y, 268 incident cases of prostate cancer, including 113 advanced cases, were identified.We observed a nonsignificant inverse association between total prostate cancer and total menaquinone intake [multivariate relative risk (highest compared with lowest quartile): 0.65; 95% CI: 0.39, 1.06]. The association was stronger for advanced prostate cancer (0.37; 0.16, 0.88; P for trend 0.03). Menaquinones from dairy products had a stronger inverse association with advanced prostate cancer than did menaquinones from meat. Phylloquinone intake was unrelated to prostate cancer incidence (1.02; 0.70, 1.48).
Conclusions: Our results suggest an inverse association between the intake of menaquinones, but not that of phylloquinone, and prostate cancer. Further studies of dietary vitamin K and prostate cancer are warranted.
Background Tocopherols may protect against prostate cancer and cardiovascular disease (CVD).
Methods We assessed the effect of walnuts, which are rich in tocopherols, on markers of prostate and vascular health in men at risk for prostate cancer. We conducted an 8-week walnut supplement study to examine effects of walnuts on serum tocopherols and prostate specific antigen (PSA). Subjects (n = 21) consumed (in random order) their usual diet +/- a walnut supplement (75 g/d) that was isocalorically incorporated in their habitual diets. Prior to the supplement study, 5 fasted subjects participated in an acute timecourse experiment and had blood taken at baseline and 1, 2, 4, and 8 h after consuming walnuts (75 g).
Results During the timecourse experiment, triglycerides peaked at 4 h, and gamma-tocopherol (γ-T) increased from 4 to 8 h. Triglyceride – normalized γ-T was two-fold higher (P = 0.01) after 8 versus 4 h. In the supplement study, change from baseline was +0.83 ± 0.52 μmol/L for γ-T, -2.65 ± 1.30 μmol/L for alpha-tocopherol (α-T) and -3.49 ± 1.99 for the tocopherol ratio (α-T: γ-T). A linear mixed model showed that, although PSA did not change, the ratio of free PSA:total PSA increased and approached significance (P = 0.07). The α-T: γ-T ratio decreased significantly (P = 0.01), partly reflecting an increase in serum γ-T, which approached significance (P = 0.08).
Conclusion The significant decrease in the α-T: γ-T ratio with an increase in serum γ-T and a trend towards an increase in the ratio of free PSA:total PSA following the 8-week supplement study suggest that walnuts may improve biomarkers of prostate and vascular status.
University of Wisconsin School of Pharmacy, Division of Pharmacy Practice, 1031 Rennebohm Hall, Madison, WI, USA. firstname.lastname@example.org
Abstract Every year nearly 200,000 men in the United States are diagnosed with prostate cancer (PCa), and another 29,000 men succumb to the disease. Within certain regions of the world population based studies have identified a possible role for green tea in the prevention of certain cancers, especially PCa. One constituent in particular, epigallocatechin-3-gallate also known as EGCG has been shown in cell culture models to decrease cell viability and promote apoptosis in multiple cancer cell lines including PCa with no effect on non-cancerous cell lines. In addition, animal models have consistently shown that standardized green tea polyphenols when administered in drinking water delay the development and progression of PCa. Altogether, three clinical trials have been performed in PCa patients and suggest that green tea may have a distinct role as a chemopreventive agent. This review will present the available data for standardized green tea polyphenols in regard to PCa chemoprevention that will include epidemiological, mechanism based studies, safety, pharmacokinetics, and applicable clinical trials. The data that has been collected so far suggests that green tea may be a promising agent for PCa chemoprevention and further clinical trials of participants at risk of PCa or early stage PCa are warranted.
Conclusion What has become evident over time is the necessity to use standardized green tea polyphenols for interventional purposes as opposed to a green tea infusion. This is an important point to illustrate being that with a green tea infusion there is no assurance of the contents of the infusion being that environment, cultivation, and brewing technique can influence the content of a green tea infusion. This point could not be further illustrated in the example of a previous clinical trial that evaluated an unstandardized green tea infusion in metastatic prostate cancer patients. Regrettably, the results of this study halted a second study where several patients receiving what is now considered a low dose of green tea extract showed a delay in the elevation of PSA in several patients. As mentioned earlier a recent clinical trial has now been performed using a standardized green tea extract (e.g. Polyphenon E) in patients undergoing radical prostatectomy a decrease in prostate-specific antigen, hepatocyte growth factor, and vascular endothelial growth factor in prostate cancer patients is observed (McLarty et al. 2009). It is imperative that future studies that are evaluating plant based materials be well characterized before clinical trials are performed. The evidence that has been collected by multiple investigators suggests that green tea may be a promising agent for PCa chemoprevention and further clinical trials of participants at risk of PCa or early stage PCa are warranted.
Jessica K. Campbell*, Kirstie Canene-Adams*, Brian L. Lindshield*, Thomas W.-M. Boileau*,, Steven K. Clinton** and John W. Erdman, Jr*,3
Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801; Procter and Gamble Pet Health and Nutrition, Lewisburg, OH 45338; ** Divison of Hematology and Oncology, Department of Internal Medicine, James Cancer Hospital and Solove Research Institute, Columbus, OH 43210
Mounting evidence over the past decade suggests that the consumption of fresh and processed tomato products is associated with reduced risk of prostate cancer. The emerging hypothesis is that lycopene,the primary red carotenoid in tomatoes, may be the principle phytochemical responsible for this reduction in risk. A number of potential mechanisms by which lycopene may act have emerged,including serving as an important in vivo antioxidant, enhancing cell-to-cell communication via increasing gap junctions between cells, and modulating cell-cycle progression. Although the effect of lycopene is biologically relevant, the tomato is also an excellent source of nutrients, including folate, vitamin C,and various other carotenoids and phytochemicals, such as polyphenols,which also may be associated with lower cancer risk. Tomatoes also contain significant quantities of potassium, as well as some vitamin A and vitamin E. Our laboratory has been interested in identifying specific components or combination of components in tomatoes that are responsible for reducing prostate cancer risk. We carried out cell culture trials to evaluate the effects of tomato carotenoids and tomato polyphenols on growth of prostate cancer cells. We also evaluated the ability of freeze-dried whole-tomato powder or lycopene alone to reduce growth of prostate tumors in rats. This paper reviews the epidemiological evidence,evaluating the relationship between prostate cancer risk and tomato consumption, and presents experimental data from this and other laboratories that support the hypothesis that whole tomato and its phytochemical components reduce the risk of prostate cancer.
Conclusion A majority of prospective and case-control epidemiological studies support the hypothesis that diets rich in tomatoes and tomato products are associated with a reduced risk of prostate cancer(5,23). In vitro studies and animal trials using tomato and tomato phytochemicals have provided further data supporting these epidemiological associations. Several small clinical trials have also suggested that supplementation with tomatoes or tomato extract may positively influence biomarkers related to prostate carcinogenesis consistent with a reduction in risk. The various components of tomatoes, including carotenoids and polyphenols,that may mediate anticarcinogenic effects remain speculative.Considerable attention has focused on lycopene as the primary compound that may contribute to decreased prostate cancer risk,yet this hypothesis requires further investigation as studies of pure lycopene as a chemopreventive agent are only beginning to be reported (30–32). Other components may influence prostate carcinogenesis, such as other tomato carotenoids and polyphenols, perhaps in combination with lycopene, and warrant further investigation in animal and human studies. Although several plausible anticarcinogenic mechanisms of tomato components have been proposed, it is essential to emphasize the necessity of research in humans to support these hypotheses. Because ofthe abundance of supporting data from epidemiological, in vitro,animal, and small clinical studies, it is time to begin to evaluate the relation of tomatoes to prostate cancer risk in larger intervention studies, which would provide a more definitive test of the hypothesist hat increased intake of tomatoes and tomato products decreases the risk of prostate cancer.
Differential effects of whole soy extract and soy isoflavones on apoptosis in prostate cancer cells Anna Hsu1, Tammy M Bray1,2, William G Helferich3, Daniel R Doerge4 and Emily Ho1,2,
1 Department of Nutrition and Exercise Sciences, 103 Milam Hall 2 Linus Pauling Institute, 571 Weniger Hall, Oregon State University, Corvallis, OR 97331 3 Department of Food Science and Human Nutrition, University of Illinois, Urbana-Champaign, IL 61801 4 National Center for Toxicological Research, Jefferson, AR 72079, USA
Abstract Previous studies have suggested that soy isoflavones exert anticarcinogenic effects against prostate cancer. We propose that soy extracts,containing a mixture of soy isoflavones and other bioactive components, would be a more potent chemo-preventive agent than individual soy isoflavones. We compared the apoptotic effects of whole soy extracts and individual soy isoflavones, genistein and daidzein, on prostate cancer cells. The soy extract contained 50% w/w of total isoflavones with approximately 1:5.5:3.5 ratios of genistin, daidzin and glycitin, respectively. Benign prostate hyperplasia (BPH-1), LnCap and PC3 cells were treated with varying concentrations of soy extract, genistein or daidzein and analyzed for cell cycle alterations and induction of apoptosis. At equal concentrations (25 µmol/L), soy extract induced a significantly higher percentage of cells undergoing apoptosis than genisteinor daidzein (P < 0.001). No significant changes in cell cycle arrest or apoptosis were observed in non-cancerous BPH-1 cells treated with soy extract, suggesting that the effects of soy extract may be tumor cell specific. On the contrary, both genistein and daidzein induced apoptosis in BPH-1 cells, suggesting that individual isoflavones may have cytotoxicity in non-cancerouscells. Soy extracts also increased Bax expression in PC3 cells,but no significant changes in nuclear factor B (NFB) activation were detected, suggesting that the induction of apoptosis was independent of the NFB pathway. Food products that bear a combination of active compounds may be more efficacious and safer as chemo-preventive agents than individual compounds. This ‘whole-food’-based approach is significant for the development of public health recommendations for prostate cancer prevention.
Abstract Background Broccoli is a Brassica vegetable that is believed to possess chemopreventive properties. Selenium also shows promise as an anticancer agent. Thus, selenium enrichment of broccoli has the potential to enhance the anticancer properties of broccoli sprouts.
Method Selenium-enriched broccoli sprouts were prepared using a sodium selenite solution. Their anticancer properties were evaluated in human prostate cancer cell lines and compared with those of a control broccoli sprout extract.
Results Selenium-enriched broccoli sprouts were superior to normal broccoli sprouts in inhibiting cell proliferation, decreasing prostate-specific antigen secretion, and inducing apoptosis of prostate cancer cells. Furthermore, selenium-enriched broccoli sprouts but, not normal broccoli sprouts, induced a downregulation of the survival Akt/mTOR pathway.
Conclusion Our results suggest that selenium-enriched broccoli sprouts could potentially be used as an alternative selenium source for prostate cancer prevention and therapy.
Samueli Institute, 1700 Diagonal Road, Suite 400, Alexandria, VA 22314, USA.
BACKGROUND: Homeopathy is a complementary medicine widely used around the world. Despite extensive use of homeopathy for cancer and other serious conditions with reported success, clinical and laboratory research has been equivocal, and no rigorous research has been done on cancer. In 1999, the US National Cancer Institute evaluated the effects of homeopathic treatment of cancer from a clinic in India and has released a request for protocols to conduct further research into this treatment. Therefore, the authors conducted a series of carefully controlled laboratory studies evaluating the effects of commonly used homeopathic remedies in cell and animal models of prostate cancer.
STUDY DESIGN: One hundred male Copenhagen rats were randomly assigned to either treatment or control groups after inoculation with prostate tumor cells.
METHODS: Prostate tumor cells DU-145, LNCaP, and MAT-LyLu were exposed to 5 homeopathic remedies. Male Copenhagen rats were injected with MAT-LyLu cells and exposed to the same homeopathic remedies for 5 weeks. In vitro outcomes included tumor cell viability and apoptosis gene expression. In vivo outcomes included tumor incidence, volume, weight, total mortality, proliferating cell nuclear antigen (PCNA) expression, apoptotic cell death (terminal deoxynucleotidyl transferase mediated d-uridine triphosphate nick end labeling), and gene expression (rAPO-multiprobe).
RESULTS: There were no effects on cell viability or gene expression in 3 prostate cell lines with any remedies at any exposure time. There was a 23% reduction in tumor incidence (P < .0001), and for animals with tumors, there was a 38% reduction in tumor volume in homeopathy-treated animals versus controls (P < .02). At time of killing, experimental animals with tumors had a 13% lower average tumor weight (P < .05). Tumors in these treated animals showed a 19% increase in apoptotic cell death (P < .05) and reduced PCNA-positive cells.
CONCLUSIONS: The findings indicate that selected homeopathic remedies for the present study have no direct cellular anticancer effects but appear to significantly slow the progression of cancer and reduce cancer incidence and mortality in Copenhagen rats injected with MAT-LyLu prostate cancer cells.
Epicatechins Purified from Green Tea (Camellia sinensis) Differentially Suppress Growth of Gender-Dependent Human Cancer Cell Lines
Mepur H. Ravindranath1, Thiruverkadu S. Saravanan1, Clarence C. Monteclaro1, Naftali Presser1, Xing Ye1, Senthamil R. Selvan2 and Stanley Brosman3 1
Department of Glycoimmunotherapy, John Wayne Cancer Institute Santa Monica, CA, 2 Cell Biology Laboratory, Hoag Cancer Center, Hoag Memorial Hospital Presbyterian Newport Beach, CA, and 3 Pacific Clinical Research Santa Monica, CA
The anticancer potential of catechins derived from green teais not well understood, in part because catechin-related growthsuppression and/or apoptosis appears to vary with the type andstage of malignancy as well as with the type of catechin. Thisin vitro study examined the biological effects of epicatechin(EC), epigallocatechin (EGC), EC 3-gallate (ECG) and EGC 3-gallate(EGCG) in cell lines from human gender-specific cancers. Celllines developed from organ-confined (HH870) and metastatic (DU145)prostate cancer, and from moderately (HH450) and poorly differentiated(HH639) epithelial ovarian cancer were grown with or withoutEC, EGC, ECG or EGCG. When untreated cells reached confluency,viability and doubling time were measured for treated and untreatedcells. Whereas EC treatment reduced proliferation of HH639 cellsby 50%, EGCG suppressed proliferation of all cell lines by 50%.ECG was even more potent: it inhibited DU145, HH870, HH450 andHH639 cells at concentrations of 24, 27, 29 and 30 µM,whereas EGCG inhibited DU145, HH870, HH450 and HH639 cells atconcentrations 89, 45, 62 and 42 µM. When compared withEGCG, ECG more effectively suppresses the growth of prostatecancer and epithelial ovarian cancer cell lines derived fromtumors of patients with different stages of disease.