Acute Myeloid Leukemia (AML) is an aggressive hematologic malignancy requiring concomitant targeting of critical cellular survival pathways due to resistance and frequent relapse with monotherapies. Venetoclax (VEN), a BCL-2 inhibitor, is one such promising clinical agent best utilized in combination therapies due to transient responses and acquired resistance. Given the involvement of the Rho/ROCK pathway in VEN activity, we combined Rho-associated coiled-coil-containing protein kinase inhibitors (ROCKi))with VEN to achieve superior antileukemic activity. The ROCKi (Fasudil, DJ4, GSK269962A) synergized with VEN to enhance cytotoxicity in both VEN-sensitive and VEN-resistant cell lines in vitro. Among the three ROCKi, GSK269962A (GSK) was best-tolerated in combination with VEN and effectively inhibited leukemia growth across multiple AML cell line-derived xenograft models in vivo. The GSK+VEN combination exhibited additive to synergistic cytotoxicity in primary AML patient cells ex vivo and enhanced antileukemic activity in a patientderived xenograft model. Additionally, the GSK+VEN combination significantly decreased the clonogenicity of primary AML cells, relatively sparing normal cells. Functional assays demonstrated enhanced apoptosis (Annexin V, caspase-3/7), elevated reactive oxygen species, and mitochondrial depolarization in both VENsensitive and VEN-resistant AML cells following combination treatment. Mechanistically, GSK augmented venetoclax responses by downregulating anti-apoptotic proteins (BCL2, MCL1) and inducing pro-apoptotic mediators (NOXA, MCL1 short isoforms), including in VEN-resistant AML cells. Together, these findings across multiple preclinical AML models demonstrate synergistic antileukemic activity and support combining VEN with ROCKi as a promising therapeutic strategy for AML.
Golla et al. (Thu,) studied this question.