title: Critical requirement of BAX for manifestation of apoptosis induced by multiple stimuli in human epithelial cancer cells.
abstract: Studies with mouse embryo fibroblasts deficient for the BCL-2 family multidomain proapoptotic proteins BAX and BAK have revealed that both of these proteins are essential for apoptosis induced by multiple stimuli, suggesting that these proapoptotic proteins are functionally overlapping in these cells [M. C. Wei et al., Science (Wash. DC), 292: 727-730, 2001; W. X. Zong et al., Genes Dev., 15: 1481-1486, 2001]. We have determined the effect of several different apoptotic stimuli in a Bax-deficient human epithelial cancer cell line (HCT116BaxKO). We show that this cell line expresses functional BAK protein and is defective in manifestation of apoptosis induced by the BH3-only proteins BIK and BID as well as extrinsic stimuli that engage the death receptors, tumor necrosis factor receptor, tumor necrosis factor-related apoptosis-inducing ligand receptor, and Fas. In addition, this cell line is deficient for apoptosis induced by cytotoxic agents such as UV, staurosporine, and thapsigargin that induce either mitochondrial or endoplasmic reticulum stress. Our results suggest that BAX plays a critical role in the manifestation of apoptosis paradigms induced by multiple stimuli in human epithelial cancer cells. Our results also suggest that the integrity of BAX may have important consequences in the progression of epithelial tumors and in determining the outcome of chemotherapeutic regimens of such tumors.
authors.affiliation: Institute for Molecular Virology, Saint Louis University Health Sciences Center, Missouri 63110, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Theodorakis
authors.forename: Elena
authors.initials: E
authors.lastname: Lomonosova
authors.forename: G
authors.initials: G
authors.lastname: Chinnadurai
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D051017:Apoptosis Regulatory Proteins; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008562:Membrane Glycoproteins / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2; D019311:Staurosporine / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand; D019284:Thapsigargin / Q000494:pharmacology; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D051028:bcl-2-Associated X Protein; D019014:fas Receptor / Q000276:immunology
chemical_list: D000906:Antibodies; D051017:Apoptosis Regulatory Proteins; C494826:BAX protein, human; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein; D019014:fas Receptor; D019284:Thapsigargin; D019311:Staurosporine