RBQ3 participates in multiple myeloma cell proliferation, adhesion and chemoresistance.

Cell adhesion mediated drug resistance (CAM-DR) is a major factor that impedes the effect of chemotherapy in multiple myeloma (MM). RBQ3, which is a RB-binding protein, played a crucial role in cell cycle process. Here, we reported that RBQ3 expression was increased gradually during the proliferation process of myeloma cells. Knocking down of RBQ3 resulted in cell cycle arrest in G1 phase and increased myeloma cells adherent to fibronectin or bone marrow stromal cells (BMSCs). Furthermore, silencing of RBQ3 reduced sensitivity to chemotherapeutic drugs in myeloma cell lines adherent to BMSCs and reduced two apoptotic marker proteins cleaved caspase-3 and cleaved PARP expression. Besides, we also found that RBQ3 participated in MAPK/ERK signal transduction pathway. In summary, these results may shed new insights into the role of RBQ3 in the development of multiple myeloma.