Subject(s)
Betacoronavirus , Coronavirus Infections/epidemiology , Pneumonia, Viral , COVID-19 , Humans , Hydroxychloroquine , Pandemics , SARS-CoV-2ABSTRACT
We studied the regulation of RANKL expression in myeloma by promoter DNA methylation. Methylation-specific polymerase chain reaction showed complete methylation of RANKL promoter in WL-2 myeloma cells but partial methylation in eight other lines. 5-AzadC treatment of WL-2 cells led to demethylation and re-expression of RANKL. Transwell and contact co-culture of WL-2 cells with normal bone marrow-derived mesenchymal stromal cells (BMSCs) resulted in comparable repression of DNA methyltransferase-1 (DNMT1) and re-expression of RANKL in WL-2 cells. Moreover, treatment of WL-2 cells with TNFα led to repression of DNMT1 and re-expression of RANKL in association with upregulation of miR-140-3p and miR-126, which are partially offset by addition of anti-TNFα antibody to transwell-coculture of WL2 with BMSC. Taken together, our results showed that TNFα in the marrow microenvironment led to RANKL demethylation and re-expression in myeloma cells through DNMT1 repression and upregulation of miR-126-3p and miR-140, both known to repress DNMT1 translation.
Subject(s)
DNA (Cytosine-5-)-Methyltransferases/metabolism , DNA Methylation/genetics , MicroRNAs/metabolism , Multiple Myeloma/genetics , Promoter Regions, Genetic , RANK Ligand/genetics , Tumor Microenvironment/genetics , Tumor Necrosis Factor-alpha/metabolism , Coculture Techniques , DNA (Cytosine-5-)-Methyltransferase 1 , Gene Expression Regulation, Neoplastic , Gene Regulatory Networks , Humans , Mesenchymal Stem Cells/metabolism , Mesenchymal Stem Cells/pathology , MicroRNAs/genetics , RANK Ligand/metabolismABSTRACT
Bone marrow mesenchymal stromal cells (MSCs) can rescue acute lymphoblastic leukemia (ALL) cells from L-asparaginase by replenishing the depleted asparagine. As both vincristine (VCR) and imatinib mesylate (IM) can inhibit MSCs' proliferation, we hypothesized that these drugs might reduce the niche support of MSCs to ALL cells. As a consequence, they can help to re-establish the cytotoxic potential of L-asparaginase on ALL cells even under MSCs support. In our study, pre-treating human MSCs with VCR but not IM, markedly reduced the protective capacity of MSCs. Furthermore, differential rescue effects were observed during addition of exogenous L-asparagine to co-culture with or without VCR pre-treatment. This supported the postulation that VCR could suppress the protective effect of MSCs to ALL cells by suppressing L-asparagine secretion. Our results suggested that the combined VCR and L-asparaginase treatment in ALL were synergistic and VCR can serve as an effective agent in suppressing the leukemic marrow microenvironment.