Analysis of SGC-7901 apoptosis induced by CSBE and regulating gene expression with laser scanning microscopy and immunofluorescence flow cytometry technique

The purpose of this article was to observe interaction between drug and cancer cell with fluorescence probes and molecular imaging technology. In order to study the effect of cell growth and apoptosis morphology of Human gastric adenocarcinoma SGC-7901 induced by n-butanol extract from Capparis spionosa L. (CSBE), laser scanning microscopy was employed to observe apoptosis imaging. In addition, the protein expression and mRNA expression of its regulating gene Bcl-2 and Bax were detected. Laser scanning microscope imaging showed cells that have bound Annexin V-FITC were in early period of apoptosis, which will show green staining in the plasma membrane. The cells that have lost membrane integrity will show red staining (PI) throughout the nucleus and a halo of green staining (FITC) on the cell surface (plasma membrane). The necrosis cells were stained by PI only. In the western blot test, CSBE could decrease the expression of Bcl-2 protein and the rate of inhibition increased as the concentration of drug rised. The immunofluorescence flow cytometry technique found that CSBE could increase the expression of Bax protein in a dose-dependent manner. Thus the rate of Bcl-2/Bax was reduced. The result of RT-PCR showed that CSBE could down-regulate the mRNA expression of Bcl-2 gene, and up-regulate the mRNA expression of Bax gene, which meant that it was by regulating gene transcription level. Eventually the apoptosis of human gastric cancer SGC-7901 cell is induced through mitochondrial signal transduction pathway.