Taxol induced Bcl-2 protein phosphorylation in human hepatocellular carcinoma QGY-7703 cell line.
Bcl-2 family proteins play a critical role in the regulation of apoptosis. Treatment of a human hepatocellular carcinoma cell line, QGY-7703, with Taxol induced apoptosis and Bcl-2 protein phosphorylation. Microscopic observation indicated that apoptotic bodies (0-15%) of Taxol-treated QGY cells appeared after 12 h of treatment, and apoptotic QGY cells gradually increased to 40% after 24 h and 70% after 48 h. A DNA fragmentation assay showed that Taxol induced genomic DNA cleavage into 200 bp DNA fragments. Bcl-2 protein was phosphorylated in Taxol-treated QGY cells within 3 h of treatment, and continued gradually up to 24 h. By 48 h, the protein was unphosphorylated. Other Bcl-2 family proteins, including Bax (a heterodimerization partner of Bcl-2), Bcl-XL, Bak and Bad, were expressed, but at constant levels. The results show a close correlation between Bcl-2 phosphorylation and apoptosis in QGY cells. The inactivation of Bcl-2 protein phosphorylation could be one of the key mechanisms needed for the induction of apoptosis in Taxol-treated QGY cells.
Cheng
S C
SC
Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, SAR China.
Luo
D
D
Xie
Y
Y
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D053938:DNA Fragmentation / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D017239:Paclitaxel / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D019253:Proto-Oncogene Proteins c-bcl-2; D017239:Paclitaxel