OCT-4, an embryonic stem cell marker expressed in breast, brain and thyroid carcinomas compared to testicular carcinoma

Cancer stem cells are a small subpopulation of cells within a tumor which are responsible for maintaining the tumor mass. A number of factors such as OCT-4 that govern the fate of adult stem cells also play a role in malignant cell transformation. OCT-4 is a key regulator of self-renewal in embryonic stem cells; its expression is potentially correlated with tumorigenesis and can affect some aspects of tumor behavior such as tumor recurrence or resistance to therapies. We have investigated the potential expression of OCT-4 on a panel of tumors including breast, brain, thyroid and testicular carcinomas, using immunohistochemistry. The level of expression of OCT-4 was then compared to different tumor types and degree of differentiation. OCT-4 was expressed at the highest levels on nuclear site of seminoma compared with other tumors. The expression of OCT-4 was detectable in both nucleus and the cytoplasm of almost all breast tumors, but it was detectable at much lower level in normal breast tissues. OCT-4 expression was noted on poorly differentiated papillary carcinoma of thyroid compared to normal follicles of thyroid gland adjacent to the tumor. Breast carcinomas and papillary carcinomas of thyroid express elevated levels of embryonic stem cell gene OCT-4, suggesting that these tumors may contain cells indicative of embryonic-like stem cells. Identification of cancer stem cells in different malignant tumors may be useful for prognostic evaluation and administration of a new treatment which target this sub-population of tumor cells

Study of rose bengal-induced cell death in melanoma cells in the absence of light

Melanoma is among the top six cancers as a cause of death and morbidity. Unfortunately there has been little progress in the medical treatment of metastatic melanoma, because of its resistance to current chemotherapeutic agents. In view of this, there is much interest in the identification of new agents for the treatment of melanoma. Rose Bengal [RB] has been used as a systemic diagnostic of hepatic function, ophthalmic diagnostic and photosensitiser in photodynamic treatment. In the present study, effects of RB, not as a photosensitiser, was tested in melanoma cells in the absence of light. Human melanoma cell lines, Me4405, Me1007, IgR3, Mel-FH, Mel-RM, Mel-CV, MM200, Sk-Mel-28 and fibroblast cells were cultured in DMEM medium. Cell death was quantitated by MTT assay. Apoptotic cells were determined using PI staining of DNA fragmentation by flow cytometry [sub-G1 peak]. The result showed RB could induce pronounced cell death in different melanoma cell lines but not in fibroblast cells. This toxicity was predominantly induced by non-apoptotic cell death but in some cell lines, RB could also induce apoptotic cell death. RB may be considered as a promising chemotherapeutic agent for the treatment of melanoma in the future

Effect of different glucose concentrations on PC12 cells apoptosis: role of bax and Bcl[2] proteins

In diabetics, hyperglycemia is associated with neuropathy, nephropathy, and retinopathy. However, direct toxic effects of glucose on neurons are still largely unknown. Firstly, cellular vital capacity was determined by MTT. Then, effects of different glucose concentrations and the role of Bax protein-induced apoptosis in PC12 cells was examined by Hoechst staining and western blotting techniques, respectively. During MTT, cells revealed to have a meaningful apoptosis at hours 48, 72, and 96 when compared with controls [p<0.01]. Apoptosis was induced suitably at a glucose concentration of 13.5mg/dl after 72 hours. Western blotting showed a significant expression of Bax protein in PC12 cells treated with increased glucose concentrations for 72 hours. Increment in glucose concentration may induce apoptosis in PC12 cells. This process occurred under the intense influence of Bax protein