The Mechanism And Anti-myeloma Immunity Effects Of Combined Treatment With Hypomethylating Drug And Donor Lymphocyte Infusion In Multiple Myeloma

Background:Multiple myeloma(MM) is a hematological malignancy, which is characterized by a proliferation of malignant plasma cells. Demethylation drug Decitabine (DAC) combined with donor lymphocytes infusion may have the likely synergistic benefits of treatment for multiple myeloma. Based on immune-genicity of Cancer-Testis Antigens (CTAs), demethylation of CTAs seems a potentially active site in MM patients with decitabine treatment.Objective:To explore the mechanism and anti-myeloma immunity effects of Decitabine combined with donor lymphocyte infusion in multiple myeloma treatment.Methods:The proliferation inhibition of DAC was evaluated by cck-8. The apoptosis was investigated by flow cytometry with AnnexinV-FITC/PI staining. The cell cycle was detected by flow cytometry with PI staining. CTAs expression was detected in multiple myeloma cell lines, primary myeloma cells and exnograft tumors by RT-PCR and Q-PCR. Balb/c mice were injected with multiple myeloma cell lines SP2/0 and MPC-11, followed by administration with DAC (0.5mg/kg dose) or PBS, with or without DLI from CB6F1 splenic cells. We observed the size of exnograft tumors and the survival of the SP2/0 or MPC-11-loaded mice and detected the specific cytotoxic T cells’activity by histopathology and Flow cytometry.Results: Proliferation of myeloma cells was inhibited by DAC in time-dependent manner. DAC induced the apoptosis of mycloa cells in dose-dependent manner. DAC is a cell cycle-specific drug, which can arrest the cells at G2/M phase. CTAs are upregulated after DAC treatment in vivo and in vitro. DAC benefits longer survival and reduces tumor volume of the myeloma mice. DAC combined with DLI inhibited the infiltration of Treg cells in spleen.