Author(s): Willems L, Jacque N, Jacquel A, Neveux N, Maciel TT,
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Abstract Cancer cells require nutrients and energy to adapt to increased biosynthetic activity, and protein synthesis inhibition downstream of mammalian target of rapamycin complex 1 (mTORC1) has shown promise as a possible therapy for acute myeloid leukemia (AML). Glutamine contributes to leucine import into cells, which controls the amino acid/Rag/mTORC1 signaling pathway. We show in our current study that glutamine removal inhibits mTORC1 and induces apoptosis in AML cells. The knockdown of the SLC1A5 high-affinity transporter for glutamine induces apoptosis and inhibits tumor formation in a mouse AML xenotransplantation model. l-asparaginase (l-ase) is an anticancer agent also harboring glutaminase activity. We show that l-ases from both Escherichia coli and Erwinia chrysanthemi profoundly inhibit mTORC1 and protein synthesis and that this inhibition correlates with their glutaminase activity levels and produces a strong apoptotic response in primary AML cells. We further show that l-ases upregulate glutamine synthase (GS) expression in leukemic cells and that a GS knockdown enhances l-ase-induced apoptosis in some AML cells. Finally, we observe a strong autophagic process upon l-ase treatment. These results suggest that l-ase anticancer activity and glutamine uptake inhibition are promising new therapeutic strategies for AML.
This article was published in Blood
and referenced in Journal of Cancer Science & Therapy