Autophagy In The Role Of Apoptosis In U937 Cells Induced By Realgar Transforming Solution

RTS is a new type of arsenic agent that is developed by our laboratory.The studies showed the RTS has significant activity in anti-leukemia and anti-tumor in vitro.However,the mechanism remains to be further study.Autophagy is a common physiological phenomenon in eukaryotic cells.It is not only related to maintaining cellular homeostasis,but also maintaisn cell survival or trigger programed cell death under stress conditions.In this thesis,we focus on the role of autophagy plays in RTS induced cell apoptosis process.Lymphoma cell line U937 which was confirmed to be sensitive to arsenic agents was selected in this thesis.Then a multi-drug resistance cell line U937/VCR was successfully established by increased dose of Vincristine.After then we studied the inhibitory effect on U937 and U937/VCR cells caused by ATO,Realgar and RTS.At last,the mechanism and the role of autophagy played in arsenic treated cells was studied with 3-MA,known as a specific autophagy inhibitor.The results indicated that ATO,Realgar and RTS showed clearly growth inhibition on U937 and U937NCR,with the typical apoptosis phenomenon in a dose dependent manner.MDC staining showed that autophagy generally involved in the apoptosis process of the two cells induced by the arsenic agents.A suprising fact was detected by Western blotting that autophagy was activated when U937 and U937/VCR were treated with the arsenic agents in combination with 3-MA.The cell viability experiments showed that the arsenic agents with lower concentrations in combination with 3-MA could reduce the inhibition rates of the arsenic agents on U937 and U937/VCR indicating that the autophagy is a protective mechanism.While treated with the arsenic agents at the IC50 concentrations in combination with 3-MA,the inhibition rates of the arsenic agents on U937 and U937/VCR were higher,which showed that the autophagy then turned into a cell death mechanism.Overall,to meet the same efficiencies on U937 and U937/VCR,the requirement of arsenic in RTS would be the least among that in the three arsenic agents.Autophagy played the role of a double-edged sword in the cell apoptosis induced by the RTS,and RTS under different arsenic concentrations used in combination with autophagy activation agents or inhibitors could obtain better antitumor effects which has a good application prospect.