Oncotarget Podcast (AUDIO)
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Volume 11, Issue 25 of @Oncotarget reported that to examine the role of RSK in AML, the authors analyzed apoptosis and the cell cycle profile following treatment with BI-D1870, a potent inhibitor of RSK. BI-D1870 treatment increased the G2/M population and induced apoptosis in Acute Myeloid Leukemia cell lines and patient Acute Myeloid Leukemia cells. Therefore, the authors investigated whether BI-D1870 potentiates the anti-leukemic activity of vincristine by targeting mitotic exit. Combination treatment of BI-D1870 and vincristine synergistically increased mitotic arrest and apoptosis in acute leukemia cells. These data show that BI-D1870 induces apoptosis of AML cells alone and in combination with vincristine through blocking mitotic exit, providing a novel approach to overcoming vincristine resistance in AML cells. Dr. Kathleen M. Sakamoto from Stanford University School of Medicine said, "Acute myeloid leukemia (AML) is a genetically and phenotypically heterogeneous hematologic malignancy characterized by the accumulation of immature myeloid blasts with resultant peripheral blood cytopenia." Treatment of cells with microtubule targeting agents, including paclitaxel and the vinca alkaloid vincristine, blocks the proper formation of the mitotic spindle through inhibition of microtubule dynamics, resulting in the prolonged mitotic arrest of cancer cells. MTAs-treated mitotic arrested cells may undergo apoptosis in mitosis, however, the rapid degradation of Cyclin B due to an insufficient SAC leads to the mitotic slippage into tetraploid G1 stage in resistant cells. Though vinca alkaloid microtubule-destabilizing compounds have shown clinical efficacy against various hematological malignancies and were included in combination chemotherapy of the VAPA study, they are not currently used in induction chemotherapy for AML due to their high toxicity against lymphoid cells and rapid degradation by myeloperoxidase in AML cells. In this study, they demonstrate that BI-D1870, a potent inhibitor of RSK, induces mitotic arrest, and apoptosis in AML cells without inhibiting CDC2 and CDC25C. Furthermore, BI-D1870 synergizes with vinca alkaloid vincristine in AML cells, suggesting that inhibition of mitotic exit with BI-D1870 could be a promising novel approach for AML therapy in combination with MTAs. The Sakamoto Research Team concluded in their Oncotarget Research Paper that BI-D1870 is a reversible pan-RSK inhibitor, showing > 500-fold higher activity for RSK than other AGC kinases. BI-D1870 also inhibits the activity of PLK1, Aurora-B, MELK, PIM3, MST2, and GSK3β at higher concentrations than for RSK. BI-D1870 and BRD7389 have been reported to inhibit proliferation and significantly increase the G2/M population in melanoma cells. BI-D1870 does not have proper physicochemical properties for clinical application. Future structure-activity relationships study for BI-D1870 is required to improve solubility and pharmacokinetic profiles for in vivo preclinical and clinical studies.
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Correspondence to - Kathleen M. Sakamoto - kmsakamo@stanford.edu To learn more about Oncotarget, please visit www.oncotarget.com
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