A small molecule inhibitor OGP46 is effective against imatinib-resistant BCR-ABL mutations including T315I through BCR-ABL/JAK-STAT pathway

Chronic myeloid leukemia (CML) is caused by the Philadelphia (Ph+) chromosome carrying the BCR-ABL oncogene, a constitutively active tyrosine kinase. The discovery of imatinib represents a major success story in the treatment against CML. However, mutations in the BCR-ABL kinase domain are a major cause of resistance to imatinib, demonstrating that BCR-ABL remains a critical drug target. Here, we investigate, a novel small molecule inhibitor, OGP46, for its the inhibitory activity against K562, a panel of murine BaF3 cell lines stably expressing either wild-type BCR-ABL or its mutant forms including T315I. OGP46 exhibits potent activity against imatinib-resistant BCR-ABL mutations including T315I. OGP46 induced cell differentiation accompanied G0/G1 cell cycle arrest and suppressed the colony formation capacity of cells. Treatment with OGP46 significantly decreased the mRNA and protein expression of BCR-ABL in K562 and BaF3-p210-T315I cells. Mechanistically, the anti-cancer activity of OGP46 inducing by cell differentiation through BCR-ABL/JAK-STAT pathway in native BCR-ABL and mutant BCR-ABL including T315I of CML cells. Our findings highlight that OGP46 is active against not only native BCR-ABL but also 11 clinically relevant BCR-ABL mutations including T315I mutation that are resistant to imatinib. Thus, OGP46 maybe a novel strategy for overcoming imatinib-resistance BCR-ABL mutations including T315I.