Altered Expression of Cellular Bcl-2 in the Progression of Hamster Cholangiocarcinogenesis

Abstract

Bcl-2 is an intracytoplasmic and membrane-associated apoptosis suppressor, and its overexpression is closely associated with survival of malignant tumors, in particular their aggressive behavior and poor prognosis. The role of Bcl-2 is, however, still controversial in cholangiocarcinogenesis because of the discrepancies in the expression of the protein. In the present study, alteration in the expression of Bcl-2 in cholangiocarcinogenesis was investigated by studying the immunoreactivities of this protein in normal, hyperplastic bile ducts with or without dysplastic changes, and neoplastic bile duct cells from a hamster cholangiocarcinoma (ChC) model. Cytoplasmic staining, which reflects high-Bcl-2 immunoreactivity, was negative to very weak in normal and hyperplastic bile ducts without dysplastic changes, while hyperplastic bile ducts with dysplasia indicated heterogeneously strong expression. On the other hand, most of the neoplastic cells of invasive cholangiocarcinomas were negative to weak as much as the level of normal bile ducts. The results suggest that the antiapoptotic factor Bcl-2 plays a limited role in the survival of highly proliferative, potentially dysplastic bile duct cells. However, the role of Bcl-2 in biliary cancer cells was not significant.

Clinical significance and effect of MTDH/AEG-1 in bladder urothelial cancer: a study based on immunohistochemistry, RNA-seq, and in vitro verification

“…We examined potential mechanisms of action of MTDH/AEG-1 in BUC by exploring the relationship between the expression of MTDH/AEG-1 and that of seven other common biomarkers: caspase-3, Bcl-2, VEGF, Ki-67, PCNA, p53, and DcR3. Sequential activation of caspase-3 plays a central role in cell apoptosis,44 the Bcl-2 gene can inhibit tumor cell apoptosis,45–47 and VEGF production by cells can stimulate vasculogenesis and angiogenesis 48,49. Ki-67 and PCNA are classical markers of cell proliferation and are routinely used by pathologists,50 whereas p53 is related to DNA repair and apoptosis 47,51.…”

The effects of vincristine sulfate on expression of galectin-3, Bcl-2, and carbohydrate structures specific for EEL, GSL-1, and RCA-1 lectins in bitches with naturally occurring canine transmissible venereal tumor

“…Bcl-2 is an intracytoplasmic and membraneassociated apoptosis suppressor (antiapoptotic protein) gene that is found in human and canine cells, and its overexpression is closely associated with the survival of malignant tumors, in particular their aggressive behavior and poor prognosis (11,12). Apoptosis is triggered by the release of proapoptotic molecules from the mitochondria by multiple mechanisms, including maintenance of mitochondrial membrane integrity and binding to proapoptotic members of the Bcl-2 family (13).…”

Therapeutic mechanism of treating SMMC-7721 liver cancer cells with magnetic fluid hyperthermia using Fe2O3 nanoparticles

“…Bcl-2 is antiapoptotic and its overexpression (Bcl-2-Bcl-2) results in apoptosis inhibition and cell survival, whereas Bax is proapoptotic ( 9 , 10 ), and its overexpression (Bax-Bax) leads to cell death. However, the expression of the apoptosis suppressor gene Bcl-2 is low or nonexistent in hepatoma cells ( 11 , 12 ), whereas Bax is widely distributed in various organs including normal liver tissues, which indicates that Bax is probably an important apoptosis-regulating gene ( 13 ). Bai et al ( 14 ) reported the abnormal expression of Bax in Hodgkin's disease.…”