ABSTRACT
OBJECTIVE: To study the molecular mechanism of TAp63gamma-induced cell apoptosis. METHODS: Transcription and protein expression of apoptosis inducing factor and p63 were investigated by immunohistochemistry and RT-PCR in human esophageal squamous carcinoma cell line EC9706 respectively. Twenty-four hours after transfection with pcDNA3.1-TAp63gamma, the apoptosis and translocation of apoptosis inducing factor in EC9706 cells were studied by flow cytometry, laser confocal microscopy and mitochondrial/cytosol/nuclear extraction analysis respectively. Down-regulation of apoptosis inducing factor protein was achieved by RNAi and pretreatment with caspase inhibitor zVAD.fmk of EC9706 cells. RESULTS: Presence of protein expressions of apoptosis inducing factor and absence of TAp63gamma was observed in the cytoplasm of untransfected cells. RT-PCR verified the subtype of p63 in EC9706 cells was DeltaNp63. After 24 hours of transfection, both nuclear and cytoplasmic expression of apoptosis inducing factor protein were observed in cells transfected with TAp63gamma and p53 expression vectors, but not in cells transfected with control vector. Cell apoptosis rates were 1.37%, 13.64%, 4.52%, 4.03% and 1.91% in the pcDNA3.1 transfection group, pcDNA3.1-TAp63gamma transfection group, apoptosis inducing factor siRNA and pcDNA3.1-TAp63gamma transfection group, zVAD.fmk treatment group, and the group receiving apoptosis inducing factor siRNA, plus zVAD.fmk treatment and pcDNA3.1-TAp63gamma transfection, respectively. CONCLUSIONS: Apoptosis inducing factor of EC9706 cells is released from mitochondria into both the cytoplasm and nucleus during TAp63gamma induced apoptosis. Down-regulation of apoptosis inducing factor inhibits TAp63gamma-induced apoptosis. Overall, TAp63gamma-induced apoptosis is dependent on the expression of apoptosis inducing factor and caspase.
Subject(s)
Apoptosis Inducing Factor/metabolism , Apoptosis , Carcinoma, Squamous Cell/pathology , Esophageal Neoplasms/pathology , Trans-Activators/metabolism , Tumor Suppressor Proteins/metabolism , Amino Acid Chloromethyl Ketones/pharmacology , Apoptosis Inducing Factor/genetics , Carcinoma, Squamous Cell/metabolism , Caspase Inhibitors , Cell Line, Tumor , Cell Nucleus/metabolism , Cytoplasm/metabolism , Down-Regulation , Esophageal Neoplasms/metabolism , Humans , Mitochondria/metabolism , Plasmids , Protein Transport , RNA Interference , RNA, Small Interfering/genetics , Trans-Activators/genetics , Transcription Factors , Transfection , Tumor Suppressor Proteins/geneticsABSTRACT
AIM: To characterize the gene expression profiles in different stages of carcinogenesis of esophageal epithelium. METHODS: A microarray containing 588 cancer related genes was employed to study the gene expression profile at different stages of esophageal squamous cell carcinoma including basal cell hyperplasia, high-grade dysplasia, carcinoma in situ, early and late cancer. Principle component analysis was performed to search the genes which were important in carcinogenesis. RESULTS: More than 100 genes were up or down regulated in esophageal epithelial cells during the stages of basal cell hyperplasia, high-grade dysplasia, carcinoma in situ, early and late cancer. Principle component analysis identified a set of genes which may play important roles in the tumor development. Comparison of expression profiles between these stages showed that some genes, such as P160ROCK, JNK2, were activated and may play an important role in early stages of carcinogenesis. CONCLUSION: These findings provided an esophageal cancer-specific and stage-specific expression profiles, showing that complex alterations of gene expression underlie the development of malignant phenotype of esophageal cancer cells.
