Preliminary Study On The Mechanisms Of Arsenic Troxide-induced Apoptosis In Human Osteosarcoma MG-63 Cells

Objective: To study the apoptotic effect of arsenic trioxide(As2O3) on human ostrosarcoma MG-63 cells, and research the potential mechanism of it. Methods: MG-63 cells were treated by arsenic trioxide for 24 hours, then assays the proliferation variant by MTT and cleavage of the DNA by TUNEL, agarose gel electrophoresis, transmission electron microscopy and flow cytometer were applied to observe the apoptotic changes of human osteosarcoma MG-63 cells induced by As2O3; Using SABC assays detected gene expression of bcl-2 ; at he last , purification the mRNA from the treated cells by Trizol, detected the expression of apoptosis related genes by cDNA microarray. Results: As2O3 causesd a dose- and time-dependent inhibition of survival and growth in human ostrosarcoma MG-63 cells. Typical apoptotic cellular changes were found after As2O3 treatment. TUNEL assays showed significant positive reaction, Agarose gel electrophorsis showed "ladder" strand of DNA, a special phenomenon of cellular apoptosis. Transmission electron microscopy showed nucleolus disappeared, chromatin condensate under nucleonic membrane, flow cytometer showed typical apoptotic peak . But the gene expression of bcl-2 had no obviously changes , cDNAmicroarray assays showed that the expression of apoptotic inhibitor gene of IEX-1 was down-regulated. The above-mentioned changes were not found in the control group. Conclusion: Our data demonstrates that As2O3 can induce apoptosis in human osteosarcoma MG-63 cell lines and its mechanism is probablely through the modulation IEX-1 instead of the modulation of bcl-2 .