JHU083

Although the anti-tumor effect of glutamine antagonism on tumor-infiltrating T cells was moderate, JHU083 promoted a stem cell-like phenotype in CD8+ T cells and decreased Treg abundance. Finally, JHU083 caused a ubiquitous shutdown in glutamine utilizing metabolic pathways in tumor cells, leading to reduced HIF-1alpha, c-MYC phosphorylation, and induction of tumor cell apoptosis, all key anti-tumor features.

Thyroid cancer exhibited enhanced glutamine metabolism, as evidenced by the glutamine dependence of thyroid cancer cells and high expression of multiple glutamine metabolism-related genes. Targeting glutamine metabolism with DON prodrug could be a promising therapeutic option for advanced thyroid cancer.

This effect is specific to TERT-expressing GBM cells because the combination of DON and BSO does not affect viability of normal astrocytes or astrocytomas that use the ALT pathway for telomere maintenance. Importantly, in vivo stable isotope tracing confirmed that combined treatment with JHU-083 (a brain-penetrant prodrug of DON) and BSO abrogates synthesis of GSH, aspartate, and pyrimidine nucleotides from [U-13C]-glutamine and induces apoptotic death in mice bearing intracranial GBM6 tumors.Collectively, our studies highlight the therapeutic potential of targeting metabolic vulnerabilities induced by TERT expression in GBMs in vivo.

Moreover, JHU-083, a specific pharmacologic inhibitor of glutaminase, killed ZFTA-RELAFUS tumor cells in vitro and in vivo. To summarize, our results suggest that the ZFTA-RELA fusion expressing tumor cells exhibit strong glutamine dependence, and targeting it has significant therapeutic relevance.

Fibrolamellar hepatocellular carcinoma (FLC) is a rare and often lethal form of liver cancer that primarily affects children and young adults. Systemic treatment of BALB/c mice bearing TIBx-FLC tumors with JHU-083, a glutamine antagonist, in combination with immune checkpoint inhibitor therapy enhanced survival as compared to vehicle or monotherapy. These data identify altered glutamine metabolism as a target in FLC, and may provide an explanation for immune suppression seen in the FLC tumor microenvironment.

Infusions with [amide-N]glutamine revealed persistent amidotransferase activity during glutaminase inhibition, and blocking these activities with the amidotransferase inhibitor JHU-083 also reduced tumor growth in both immunocompromised and immunocompetent mice. We conclude that ccRCC tumorgrafts catabolize glutamine via multiple pathways, perhaps explaining why it has been challenging to achieve therapeutic responses in patients by inhibiting glutaminase.

In addition, we found that the glutamine metabolism inhibitor JHU083 promoted the proliferation of CD8T cells and improved the efficacy of PD-1 blockers. We proposed a new tool to quantify the glutamine partitioning between tumor cells and CD8T cells, through which the unique immune microenvironment could be identified at the transcriptome level. Furthermore, the simultaneous destruction of the glutamine metabolism in tumor cells and CD8T cells facilitated the enrichment of tumor-infiltrating CD8T cells and enhanced the efficacy of immunotherapy.