[Suppressive effect of brain derived neurotrophic factor on H2O2-induced apoptosis in human lung cancer cell YTMLC-90].

Background & Objective: It has been shown that neurotrophic factors such as nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), and neurotrophin (NT-3/4) are synthesized in a variety of cells inside and outside the nervous system. These factors are not only able to promote neural survival, proliferation and apoptosis of neural cells but also relevant to the activity of neural invasion of tumors. It has not been reported to date whether BDNF may play roles in the biological behavior of human lung cancer cells. The aim of this experiment was to investigate the effect of BDNF on hydrogen peroxide (H2O2)-induced apoptosis in the human lung cancer cell line YTMLC-90.

Methods: The minigene pSVCEPBFCAT containing the promoter and enhancer elements of the human a1(I) collagen gene(COLIA1) at its 3' terminus followed by hBDNF gene cDNA was transfected and derived BDNF ectopic expression in the human lung cancer cells. The cell proliferation was measured by MTT assay. The morphological and ultra-structural changes of apoptotic cells were observed by microscopy with fluorescent stain of acridine orange and electron microscopy. The DNA fragmentation was examined by agarose gel electrophoresis.

Results: After exposure of growing cells to 200 micromol/L H2O2 for 24 hours, the inhibition rate of cell growth was 30% in the pSVCEPBFCAT-transfected YTMLC-90, 84.60% in controls of non-transfected YTMLC-90, and 80.00% in pSVCEPCAT-transfected YTMLC-90, respectively (P< 0.001). The morphological and biochemical changes of apoptotic cells such as shrinkage of cytoplasm and nucleus,fragmentation of the chromatin, and ladder pattern of DNA were commonly observed in the cell population of controls, but these apoptotic features were not discovered in the pSVCEPBFCAT-transfected YTMLC-90.

Conclusion: BDNF markedly inhibits H2O2 cytotoxicity on human lung cancer cell YTMLC-90 by promoting YTMLC-90 proliferation and antagonizing H2O2-induced apoptosis.