CLONING AND IDENTIFICATION OF A GENE RELATED TO THE DIFFERENTIATION OF HUMAN GASTRIC ADENOCARCINOMA CELLS

摘要

Objective: To compare the differential expression of mRNA between MKN-28 (highly differentiated) and MKN-45 (poorly differentiated) gastric adenocarcinoma cells and identify genes involved in human gastric adenocarcinoma differentiation. Methods: Differential expression of mRNA between MKN-28 and MKN-45 adenocarcinoma cells was investigated by fluorescent differential display (FDD). Differentially expressed cDNA was analyzed by bio-informatics and confirmed by RT-PCR and Northern-blot. Results: 45 differential fragments were finally attained. One of them (No. 10) was an approximate 750 bp cDNA and highly up-regulated in MKN-45 cells as compared with MKN-28 cells. By using Blastn and UniGene database analysis, we found the fragment was mapped to chromosome 14q11.2(q12 and showed a significant homology to Bcl-2 binding protein gene (BNip3), which was recently identified encoding pro-apoptosis protein located in mitochondrial. Conclusion: The BNip3 induced apoptosis could be suppressed by interacting with bcl-2. The BNip3 gene in tumor cells might be up-regulated by the hypoxia response element through the HIF1a transcription factor, causing death of the hypoxic cells at the center of the tumor where vascularization is usually poor in the process of tumor development.