ANTIMETABOLIC COOPERATIVITY WITH THE CLINICALLY APPROVED KIDROLASE AND TYROSINE KINASE INHIBITORS TO ERADICATE CML STEM CELLS
Long-term treatment with tyrosine kinase inhibitors (TKI) represents an effective treatment for chronic myeloid leukemia (CML) and discontinuation of TKI therapy is now proposed to patient with deep molecular responses. However, evidence demonstrating that TKI are unable to fully eradicate dormant leukemic stem cells indicate that new therapeutic strategies are needed to prevent molecular relapses. We investigated the metabolic pathways responsible for CML surviving to Imatinib exposure and its potential therapeutic utility to improve the efficiency of TKI against CML stem cells. Using complementary cell-based techniques, we demonstrated that TKI suppressed glycolysis in a large panel of BCR-ABL1 + cell lines as well as in primary CD34+ stem-like cells from CML patients. However, compensatory glutamine-dependent mitochondrial oxidation supported ATP synthesis and CML cell survival. Glutamine metabolism was inhibited by L-asparaginases such as Kidrolase without inducing predominant CML cell death. Clinically relevant concentrations of TKI render CML progenitors and stem cells susceptible to Kidrolase. The combination of TKI with L-asparaginase reactivated the intinsic apoptotic pathway leading to efficient CML cell death. Thus, targeting glutamine metabolism with the clinically-approved drug Kidrolase, in combination with TKI that suppress glycolysis represents an effective and widely applicable therapeutic strategy for eradicating CML stem cells.