Inhibition of GCN2 sensitizes ASNS-low cancer cells to asparaginase by disrupting the amino acid response

Abstract

General control nonderepressible 2 (GCN2) plays a major role in the cellular response to amino acid limitation. Although maintenance of amino acid homeostasis is critical for tumor growth, the contribution of GCN2 to cancer cell survival and proliferation is poorly understood. In this study, we generated GCN2 inhibitors and demonstrated that inhibition of GCN2 sensitizes cancer cells with low basal-level expression of asparagine synthetase (ASNS) to the antileukemic agent l-asparaginase (ASNase) in vitro and in vivo. We first tested acute lymphoblastic leukemia (ALL) cells and showed that treatment with GCN2 inhibitors rendered ALL cells sensitive to ASNase by preventing the induction of ASNS, resulting in reduced levels of de novo protein synthesis. Comprehensive gene-expression profiling revealed that combined treatment with ASNase and GCN2 inhibitors induced the stress-activated MAPK pathway, thereby triggering apoptosis. By using cell-panel analyses, we also showed that acute myelogenous leukemia and pancreatic cancer cells were highly sensitive to the combined treatment. Notably, basal ASNS expression at protein levels was significantly correlated with sensitivity to combined treatment. These results provide mechanistic insights into the role of GCN2 in the amino acid response and a rationale for further investigation of GCN2 inhibitors for the treatment of cancer.

Concurrent use of rabacfosadine and L‐asparaginase for relapsed or refractory multicentric lymphoma in dogs

“…Alternatively, previous che- which might activate pro-survival pathways. 19,20 In this study, as is consistent with previous RAB studies, 17 The schedule for L-ASP administration in this current study was based on protocols combining L-ASP with CCNU. Two such protocols have been evaluated in the literature for relapsed lymphoma in dogs.…”

“…Furthermore, the amino acid response (AAR) pathway is a well‐established regulator of gene transcription. In short, depletion of essential amino acids can lead to upregulation of key proteins, such as general control nonderepressible 2 (GCN2) and activating transcription factor 4 (ATF4), which might activate pro‐survival pathways …”

Ablation of the ASCT2 (SLC1A5) gene encoding a neutral amino acid transporter reveals transporter plasticity and redundancy in cancer cells

“…Our model predicts that combined inhibition of an amino acid loader and a rescue transporter will cause significant vulnerability in a wide range of cancer cells. In a related approach, disturbing amino acid homeostasis by asparaginase treatment in combination with GCN2 inhibition was proposed for cancer cells with low asparaginase activity (32). Our data suggest that it appears meaningful to analyze which types of cancer cells display an integrated stress response already under nutrient-rich conditions, which will render them more susceptible to disruptions of amino acid homeostasis.…”

A Compendium of Kinetic Cell Death Modulatory Profiles Identifies Ferroptosis Regulators

“…We considered the possibility that Arg deprivation inhibited erastin2-induced ferroptosis by activating the amino acid sensing GCN2/ATF4 pathway, and upregulating transsulfuration metabolism, an alternative route to cysteine synthesis [51][52][53] . Arg deprivation increased ATF4 protein expression and expression the transsulfuration pathway genes CBS and CTH (Fig.…”