LncRNA H19 overexpression induces bortezomib resistance in multiple myeloma by targeting MCL-1 via miR-29b-3p.

Radiotherapy, chemotherapy, autologous/allogeneic stem cell transplantation, and targeted drug therapy are currently available therapeutic options for multiple myeloma (MM), but the clinical outcome remains unsatisfactory owing to frequent occurrence of drug resistance. Anti apoptosis is one of the main mechanisms to mediate drug resistance. Studies have shown that MCL-1 plays a key role in the growth of cancer cells "escaping" drug attacks, but the underlying mechanism remains unclear. Our previous study demonstrated that lncRNA H19 was highly expressed in the serum of MM patients. Bioinformatics predicts that miR-29b-3p is the downstream target gene, and MCL-1 is the downstream target protein of miR-29b-3p. Therefore, we speculated that MCL-1 may be involved in the occurrence of drug resistance through epigenetics. On the basis of these previous findings, the present study was intended to explore the biological function of H19, interactions between the downstream target genes, and the effect of H19 on BTZ resistance of myeloma cells. In addition, in vivo experiments we have also confirmed that H19 promoted tumor growth and may develop resistance to bortezomib partly. It was found that H19 reduced cell sensitivity to the chemotherapeutic drug BTZ by working as a miRNA sponge to inhibit the expression of miR-29b-3p, enhance MCL-1 transcriptional translation and inhibit apoptosis. These findings may help gain insights into the molecular mechanism of acquired BTZ resistance and develop new drug targets for the clinical treatment of MM.