Effect Of Venetoclax Combined With Dexamethasone On Acute Myeloid Leukemia Cells

Objective To investigate the cytotoxic effect of BCL-2 inhibitor Venetoclax combined with dexamethasone on acute myeloid leukemia(AML)cells in vitro,and to reduce the protective effect of bone marrow mesenchymal stem cells(BM-MSCs)on AML cell lines and its potential regulatory mechanism.Methods In experiment groups,AML cell lines MOLM-13,NOMO1 and THP-1were treated with Venetoclax and dexamethasone alone or in combination,and AML cells without Venetoclax or dexamethasone in control group.The viability of AML cells was detected by cell counting kit-8 assay(CCK-8).Apoptosis of AML cells was detected by Annexin V-FITC/PI double staining assay.The expression levels of PARP,BCL-2 family proteins BCL-2,MCL-1 and BCL-XL were detected by WB.qRT-PCR was used to verify the expression of BCL-2,MCL-1 and BCL-XL genes in BCL-2family.The mitochondria of MSCs were stained with Mitotracker Deep Red reagent and then co-cultured with AML cells.Venetoclax and dexamethasone,alone or in combination,were used in the co-culture system.Apoptosis,mitochondrial membrane potential(MMP),reactive oxygen species(ROS)levels and mitochondrial fluorescence signals in AML cells were detected by flow cytometry.Results Dexamethasone had no significant effect on AML cell viability and apoptosis.The combination of dexamethasone and Venetoclax enhanced the Venetoclax effect on AML cell viability and caused more AML cell apoptosis than Venetoclax alone.WB results showed that dexamethasone alone increased the expression of MCL-1 protein in AML cells compared with the control group,and the combination of dexamethasone and Venetoclax also increased the expression of MCL-1 protein in AML cells.When AML cells were co-cultured with MSCs,the presence of MSCs reduced the venetoclaxinduced apoptosis of AML cells,but the venetoclax-induced apoptosis was still increased by dexamethasone combined with Venetoclax.In co-culture,Venetoclax increased ROS levels in AML cells and the transfer of mitochondria from MSCs to AML cells,while dexamethasone decreased ROS levels and the transfer of mitochondria from MSCs to AML cells.Dexamethasone combined with Venetoclax reduced venetoclax-induced ROS levels in AML cells and reduced the transfer of mitochondria from MSCs to AML cells,which may lead to a weakened protective effect of MSCs on AML cells.Conclusion Dexamethasone enhanced the anti-tumor effect of Venetoclax in vitro,Venetoclax combined with dexamethasone reduced venetoclax-induced ROS levels in AML cells and decreased the transfer of mitochondria from MSCs to AML cells,which may lead to attenuated protective effect of MSCs on AML cells.