Novel synthetic 4-chlorobenzoyl berbamine inhibits c-Myc expression and induces apoptosis of diffuse large B cell lymphoma cells.

Abstract

C-Myc expression is associated with poor prognosis and aggressive progression of diffuse large B cell lymphoma (DLBCL), and the development of drug-like c-Myc inhibitors remains challenging. In this study, we report a novel berbamine derivative termed 4-chlorobenzoyl berbamine (CBBM) that potently induced the apoptosis of c-Myc-overexpressing DLBCL cells but spared normal blood cells. The compound showed IC50 values ranging from 1.93 to 3.89μmol/L in DLCBL cells and exhibited a 4.75- to 9.64-fold increase in anti-tumor activity compared to berbamine. Additionally, CBBM inhibited the proliferation of the DLBCL line OCI-Ly3 cells through G0/G1 cell-cycle arrest and induced apoptosis. Further studies have shown that CBBM treatment leads to the proteasome-dependent degradation of c-Myc protein in OCI-Ly3 cells. Interestingly, we found that the inhibitory effect of CBBM was positively correlated with basal levels of CaMKIIγ, which is a key inducer of c-Myc expression in DLBCL cells. We also observed that CBBM inhibits the JAK2/STAT3 pathway, leading to reduced c-Myc transcription. Collectively, these findings suggest that CBBM could be a promising lead compound for treatment of c-Myc-driven DLBCL.