PMA/IONO affects diffuse large B-cell lymphoma cell growth through upregulation of A20 expression

Diffuse large B-cell lymphoma (DLBCL) is a common non-Hodgkin lymphoma. A20 and mucosa-associated lymphoid tissue lymphoma translocation gene 1 (MALT1) are known to be related to DLBCL pathogenesis and progression. This study aimed to assess the effects of phorbol myristate acetate/ionomycin (PMA/IONO) on the growth and apoptosis of the DLBCL cell line OCI-LY1, and their associations with A20, MALT1 and survivin levels. Cell viability was assessed by MTT assay. Cell cycle distribution and apoptosis were evaluated using flow cytometry after incubation with Annexin V-FITC/propidium iodide (PI) and RNase/PI, respectively. Gene and protein expression levels were determined by quantitative real-time PCR and western blotting, respectively. To further determine the role of A20, this gene was silenced in the OCI-LY1 cell line by specific siRNA transfection. A20 protein levels were higher in the OCI-LY1 cells treated with PMA/IONO compared with the controls, and were positively correlated with the concentration and treatment time of IONO, but not with changes of PMA and MALT1. Meanwhile, survivin expression was reduced in the OCI-LY1 cells after PMA/IONO treatment. In addition, OCI-LY1 proliferation was markedly inhibited, with a negative correlation between cell viability and IONO concentration. In concordance, apoptosis rates were higher in the OCI-LY1 cells after PMA + IONO treatment. Cell cycle distribution differed between the OCI-LY1 cells with and without PMA/IONO treatment only at 24 h, with increased cells in the G0/G1 stage after PMA/IONO treatment. These findings indicate that PMA/IONO promotes the apoptosis and inhibits the growth of DLBCL cells, in association with A20 upregulation. Thus, A20 may be a potential therapeutic target for DLBCL.