Abstract Background Methanolic extracts of Gracilaria tenuistipitata (MEGT) were obtained from the edible red algae. Previously, we found that water extract of G. tenuistipitata was able to modulate oxidative stress-induced DNA damage and its related cellular responses.
Methods In this study, the methanol extraction product MEGT was used to evaluate the cell growth inhibition in oral cancer cells and its possible mechanism was investigated.
Results The cell viability of MEGT treated Ca9-22 oral cancer cell line was significantly decreased in a dose–response manner (p < 0.05). The sub-G1 population and annexin V intensity of MEGT-treated Ca9-22 cancer cells were significantly increased in a dose–response manner (p < 0.0005 and p < 0.001, respectively). The γH2AX intensities of MEGT-treated Ca9-22 cancer cells were significantly increased in a dose–response manner (p < 0.05). The reactive oxygen species (ROS) and glutathione (GSH)-positive intensities of MEGT-treated Ca9-22 oral cancer cells were significantly increased and decreased, respectively, in a dose–response manner (p < 0.05). The DiOC2(3) intensity for mitochondrial membrane potential (MMP) of MEGT-treated Ca9-22 cancer cells was significantly decreased in a dose–response manner (p < 0.05).
Conclusions These results indicated that MEGT had apoptosis-based cytotoxicity against oral cancer cells through the DNA damage, ROS induction, and mitochondrial depolarization. Therefore, MEGT derived from the edible algae may have potential therapeutic effects against oral squamous cell carcinoma (OSCC).
Source : BMC Complementary and Alternative Medicine 2012, 12:142 doi:10.1186/1472-6882-12-142 Link to Full Article
Quercetin Induces Necrosis and Apoptosis in SCC-9 Oral Cancer Cells Maricela Haghiac and Thomas Walle
Abstract Evidence has accumulated that dietary polyphenols, in particular, flavonoids, have protective effects against oral cancer. In this study, we have examined the effects of quercetin, a major dietary flavonoid, on cell growth and necrosis/apoptosis and cell cycle regulation in human oral squamous carcinoma SCC-9 cells. Quercetin induced dose- and time-dependent, irreversible inhibition of cell growth and cellular DNA synthesis. Light microscopy and lactate dehydrogenase measurements showed modifications in the morphology and membrane integrity of these cells after quercetin treatment. Propidium iodide/annexin V staining showed that quercetin induced necrosis at 24 h and 48 h, whereas at 72 h cells underwent apoptosis, correlating with caspase-3 activation. Flow cytometry studies of the cell cycle distribution showed that quercetin induced mainly S-phase arrest. Thymidylate synthase (TS), a key S-phase enzyme, was inhibited in a time- and dose-dependent fashion by quercetin at the protein level. A lack of effect on TS mRNA suggested that TS down-regulation occurred at the translational level. In conclusion, our data support a view that quercetin initially induces a stress response, resulting in necrosis of these oral epithelial cells. Prolonged exposure of the surviving cells to quercetin causes apoptosis, presumably mediated by inhibition of TS protein.
Antiproliferative effect of Tualang honey on oral squamous cell carcinoma and osteosarcoma cell lines
Abdulmlik A Ghashm1, Nor H Othman2, Mohammed N Khattak2, Noorliza M Ismail1, Rajan Saini1*
Cancer of the oral cavity is eleventh most common malignancy worldwide  while in the Indian subcontinent and regions of Southeast Asia, it is the predominant malignancy accounting for up to 40% of all the cancers . This high incidence of oral cancer is primarily attributable to the habit of tobacco, betel quid chewing and alcohol consumption . Oral squamous cell carcinomas (OSCC) are the most common type of oral cancers. Similarly, Human Osteosarcomas (HOS) that arise from the jaw, account for 2.1% of all malignant oral and maxillofacial tumours . The treatment of these types of oral cancers includes surgery and/or radiotherapy, which are often associated with loss of function, disfigurement and reduced quality of life . Recently, advances in chemotherapeutic agents for the treatment of OSCCs have been highlighted but the survival rate of patients has not improved significantly. The development of novel therapeutic agents targeting the malignant behaviour of these cancers is important to improve the prognosis of treatment . The study of molecular mechanisms of chemotherapeutic agents and the combination of chemotherapeutic agents that induce synergistic anticancer activity are necessary to improve clinical outcomes .
Many researchers have studied the anticancer activities of drugs or herbal extracts on OSCC cell lines. These include Tamoxifen in combination with Cisplatin , 5-Fluorouracil , Cordycepin , Scutellaria baicalensis , Quercetin  Artemisinin  and others. Similarily, Ginsenoside Rg1, Cinnamic acid, and Tanshinone IIA , Diosgenin, Venenum Bufonis and Oxgall powder have been shown to have antiproliferative effect on HOS cell lines. Honey is a food product which is collected from various plants and processed by honey bees (Apis mellifera). Honey has been used as traditional medicine for centuries in different cultures, not only for its nutritional value but also its healing properties. Recently, honey has been tested and approved scientifically for its functional and biological properties like anti-oxidant, anti-inflammatory, anti-bacterial, anti-viral, anti-ulcerous activities, anti-lipid and anti-cancer properties [16-23]. These activities are mainly attributed to the phenolic compounds such as flavonoids having antioxidant properties and radical scavenging activities seen among all types of honeys in different proportions, depending on the geographical areas, source of honeybee food and climate [24-26]. Honey has also been used in palliative care of various cancers like in radiation-induced mucositis, radiotherapy and chemotherapy induced skin reactions and wounds . It has also been shown to produce antiproliferative effects in bladder cancer , colon cancer , mammary carcinoma and fibrosarcoma . However, till date no study has been found to show antiproliferative effects of honey on oral cancers. Malaysian Tualang honey is collected from the honey combs of Asian rock bees (Apis dorsata), which build their hives high up in the Tualang tree (Koompassia excelsa). Tualang honey is used commonly as a medicinal product  and as a food in Malaysia. Recently, antibacterial properties of this honey have been studied and compared with other honeys [30,31]. However, its antiproliferative properties are yet to be studied. The purpose of the current study was to investigate the antiproliferative activity of Malaysian Tualang honey on OSCC and HOS cell lines.
Several concentrations of Tualang honey (1% - 20%) were applied on OSCC and HOS cell lines for 3, 6, 12, 24, 48 and 72 hours. Morphological characteristics were observed under light and fluorescent microscope. Cell viability was assessed using MTT assay and the optical density for absorbance values in each experiment was measured at 570 nm by an ELISA reader. Detection of cellular apoptosis was done using the Annexin V-FITC Apoptosis Detection Kit.
Morphological appearance showed apoptotic cellular changes like becoming rounded, reduction in cell number, blebbed membrane and apoptotic nuclear changes like nuclear shrinkage, chromatin condensation and fragmented nucleus on OSCC and HOS cell lines. Cell viability assay showed a time and dose-dependent inhibitory effect of honey on both cell lines. The 50% inhibitory concentration (IC50) for OSCC and HOS cell lines was found to be 4% and 3.5% respectively. The maximum inhibition of cell growth of ≥80% was obtained at 15% for both cell lines. Early apoptosis was evident by flow cytometry where percentage of early apoptotic cells increased in dose and time dependent manner.
Tualang honey showed antiproliferative effect on OSCC and HOS cell lines by inducing early apoptosis.
Cranberry and Grape Seed Extracts Inhibit the Proliferative Phenotype of Oral Squamous Cell Carcinomas
Kourt Chatelain, Spencer Phippen, Jonathan McCabe, Christopher A. Teeters, Susan O’Malley* and Karl Kingsley*
Department of Biomedical Sciences, School of Dental Medicine, University of Nevada, Las Vegas, USA
Proanthocyanidins, compounds highly concentrated in dietary fruits, such as cranberries and grapes, demonstrate significant cancer prevention potential against many types of cancer. The objective of this study was to evaluate cranberry and grapeseed extracts to quantitate and compare their anti-proliferative effects on the most common type of oralcancer, oral squamous cell carcinoma. Using two well-characterized oral squamous cell carcinoma cell lines, CAL27 and SCC25, assays were performed to evaluate the effects of cranberry and grape seed extract on phenotypic behaviors of these oralcancers. The proliferation of both oralcancer cell lines was significantly inhibited by the administration of cranberry and grape seed extracts, in a dose-dependent manner. In addition, key regulators of apoptosis,caspase-2 and caspase-8, were concomitantly up-regulated by these treatments. However, cranberry and grape seed extracts elicited differential effects on cell adhesion, cell morphology,and cell cycle regulatory pathways. This study represents one of the first comparative investigations of cranberry and grapeseed extracts and their anti-proliferative effects on oralcancers.Previous findings using purified proanthocyanidin from grapeseed extract demonstrated more prominent growth inhibition,as well as apoptosis-inducing, properties on CAL27 cells. These observations provide evidence that cranberry and grape seed extracts not only inhibit oralcancerproliferation but also that the mechanism of this inhibition may function by triggering keyapoptotic regulators in these cell lines. This information will be of benefit to researchers interested in elucidating which dietary components are central to mechanisms involved in the mediation oforal carcinogenesis and progression.
Abstract Despite the recently reported drop in the overall death rate from cancer, the estimated survival rate and number of deaths from oral cancer remain virtually unchanged. Early detection efforts, in combination with strategies for prevention and risk-reduction, have the potential to dramatically improve clinical outcomes. The identification of non-toxic, effective treatments, including complementary and alternative therapies, is critical if the survival rate is to be improved. Epidemiologic studies have suggested a protective effect from certain plant-derived foods and extracts; however, it has been difficult to isolate and identify the compounds most responsible for these observations. The primary purpose of this study was to investigate the response of human oral squamous cell carcinoma (OSCC) to proanthocyanidin (PAC), a plant-derived compound that may inhibit the progression of several other cancers.
Methods Using a series of in vitro assays, we sought to quantify the effects of PAC on OSCC, cervical carcinoma, and non-cancerous cell lines, specifically the effects of PAC on cell proliferation. Recent data suggest that infection with the human papillomavirus (HPV) may also modulate the proliferative potential of OSCC; therefore, we also measured the effects of PAC administration on HPV-transfected OSCC proliferation.
Results Our results demonstrated that PAC administration was sufficient to significantly suppress cellular proliferation of OSCC in a dose-dependent manner. In addition, the increased proliferation of OSCC after transfection with HPV 16 was reduced by the administration of PAC, as was the proliferation of the cervical cancer and non-cancerous cell lines tested. Our results also provide preliminary evidence that PAC administration may induce apoptosis in cervical and oral cancer cell lines, while acting merely to suppress proliferation of the normal cell line control.
Conclusion These results signify that PAC may be a compelling candidate for testing in both animal and human models. Furthermore, these data provide adequate justification for elucidating the divergent mechanisms of PAC-induced proliferation, inhibition, and apoptosis among these and other cell lines.
Inhibition of Cell Proliferation and MAPKinase and AktPathways in Oral Squamous cell Carcinoma by Genistein and BiochaninA Tara L. Johnson, Maria B. Lai, James C. K. Lai and Alok Bhushan
Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy and Biomedical Research Institute, Idaho State University, Pocatello, Idaho, USA
High morbidity and mortality associated with oral squamous cell carcinoma (OSCC) are largely attributable to late stage diagnosis.Despite significant advances in therapeutic strategies, the five-year survival rate for oral cancer remains at about 50%.A chemopreventive approach may be an effective alternative or adjunct to current therapies. Previous studies have shown anti-tumor effects of isoflavones in several cancers, including oral cancer.However, their mechanisms of action are still unclear. We hypothesized that isoflavones inhibit multiple signaling pathways implicated in oral carcinogenesis. To address our hypothesis, we investigated the effects of three isoflavone derivatives, genistein, biochanin Aand daidzein, on SCC15 and SCC25 squamous cell carcinoma cell lines. In cell proliferation experiments, we found that genistein and biochanin A inhibited SCC15 and SCC25 cell growth with anIC50 of 50 µM. We also investigated the effect of isoflavones on ERK and Akt pathways. Our results, from western blot analysis,suggest that both genistein and biochanin A induced decreases in phosphorylation of ERK and Akt at treatment concentrations of 20, 50 and 100 µM. Taken together, our results clearly demonstrate a differential regulation of signaling pathways by various isoflavones in OSCC cell lines. Thus, tumor progression models can be utilized to study the preventive and therapeutic roles of isoflavones inoral cancer cell lines.