PIM1/2 KINASE INHIBITOR VI

SMI-16a has excellent potency for inhibition of both Pim-1 and Pim-2. Treatment with Pim-2 short-interference RNA as well as the Pim inhibitor SMI-16a successfully restores osteoblastogenesis suppressed by all the above inhibitory factors and MM cells. The SMI-16a treatment potentiates BMP-2-mediated anabolic signaling while suppressing TGF-β signaling.

Mice tolerate intraperitoneal dose of SMI-16a is 50 mg/kg daily for 5 days, while 100 mg/kg is overtly toxic. Treatment of the animals with SMI-16a for 5 days per week reduces the growth of tumors by approximately 50% and does not cause a loss of body weight. Subchronic dosing with SMI-16a does not affect the levels of red, white blood cells, including lymphocytes, monocytes, and granulocytes, indicating that the compound does not have myelosuppressive effects. SMI-16a does not have toxicity toward the liver as the albumin, alkaline phosphatase, and alanine aminotransferase levels are unchanged . SMI-16a effectively prevents bone destruction while suppressing MM tumor growth in MM animal models.