[Inhibitory effect of human brain myelin basic protein on H2O2-induced apoptosis of human lung cancer cell line YTLMC-90].
OBJECTIVE
Human brain myelin basic protein (MBP) distributes in nervous system and other tissues extensively, and can be detected in many kinds of tumor cells, such as lung cancer, breast cancer, and neuroglioma. However, it has not been reported whether MBP is relevant to the activity of neural invasion of tumors and whether MBP plays a role in biological behaviors of human lung cancer cells. This study was to investigate the inhibitory effect of MBP on hydrogen peroxide (H2O2)-induced apoptosis of human lung cancer cell line YTLMC-90.


METHODS
YTLMC-90 cells were transfected with plasmid pSVCEPMBPCAT containing MBP cDNA minigene (test group), or empty vector pSVCEPCAT, or received no transfection (control group), and exposed to H2O2. The expression of MBP in YTLMC-90 cells was detected by Western blot. Cell proliferation was measured by MTT assay. The morphologic and ultra-structural changes of apoptotic cells were observed by microscopy with fluorescent staining of acridine orange (AO) and electron microscopy. The DNA fragmentation was examined by agarose gel electrophoresis.


RESULTS
After exposed to 200 micromol/L H2O2 for 24 h, the inhibitory rate of cell growth was significantly lower in test group than in empty vector group and control group (36.67% vs. 78.67% and 84.00%, P<0.001). The morphologic and biochemical changes of apoptotic cells, such as shrinkage of cytoplasm and nucleus, fragmentation of chromatin, and ladder pattern of DNA, were commonly observed in cells in control group, but these apoptotic features were not discovered in test group.


CONCLUSIONS
MBP markedly inhibits H2O2 cytotoxicity to YTLMC-90 cells through promoting cell proliferation and antagonizing H2O2-induced apoptosis.
Institute of Biochemistry and Molecular Biology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, P. R. China.
Jian-Ye
JY
Chen
Xiao-Ming
XM
Wang
Ji
J
Liu
Jing-Xin
JX
Chen
Ruo-Han
RH
Wang
Wen-Zhen
WZ
Peng
Han-Hua
HH
Cheng
Jun-Jie
JJ
Chen
D017209:Apoptosis / Q000187:drug effects; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D053938:DNA Fragmentation; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D004676:Myelin Basic Protein / Q000235:genetics / Q000378:metabolism*
D018076:DNA, Complementary; D004676:Myelin Basic Protein; D006861:Hydrogen Peroxide