Faculty Bibliography

[Figure: see text].

Introduction: The KEAP1/NRF2 pathway is mutationally activated in approximately 20-25% of NSCLC patients. NRF2 activation protects against oxidative stress and promotes tumor growth and survival. KEAP1/NRF2 mutations in advanced NSCLC are associated w/ dramatically shorter survival and poor outcomes following standard-of-care therapy. These tumors have heightened dependency on glutaminase-mediated conversion of glutamine to glutamate due to upregulation of NRF2 target genes involved in glutamine metabolism, which support a massive increase in glutathione synthesis. Telaglenastat (CB-839) is an investigational, first-in-class, potent, oral glutaminase inhibitor which has demonstrated activity in KEAP1/NRF2-mutated NSCLC cell lines and xenograft models. This study will evaluate the safety and efficacy of telaglenastat + standard-of-care pembrolizumab (pembro) and chemotherapy as 1L therapy in patients with KEAP1/NRF2-mutated non-squamous metastatic NSCLC (NCT04265534; Skoulidis et al. ASCO 2020).
Method(s): This phase 2, randomized, multicenter, double-blind study will enroll ~120 patients with histologically or cytologically documented stage IV non-squamous NSCLC with KEAP1 or NRF2 mutations, no prior systemic therapy for metastatic NSCLC, measurable disease (RECIST v1.1), ECOG PS 0-1, and no EGFR, ALK, ROS, or other actionable mutation w/ available approved therapy in the1L setting. KEAP1 or NRF2 mutations will be determined by next-generation sequencing (NGS); and study-provided liquid biopsy NGS will be available. Patients will be randomized 1:1 to receive telaglenastat (800 mg BID PO) or placebo, plus pembro, carboplatin, and pemetrexed at standard doses on day 1 of each 21-day cycle. Patients will be stratified by STK11/LKB1 mutational status and M stage of cancer (M1a-b vs M1c). The study includes an initial safety run-in period (1 cycle). The co-primary endpoints are safety and investigator-assessed progression-free survival (RECIST v1.1). Secondary endpoints include overall response rate, duration of response, and overall survival, as well as performing efficacy analyses in the subgroup of patients w/ biochemical confirmation of KEAP1/NRF2 pathway activation. Findings of this novel biomarker-selected study will inform the efficacy and safety profile of telaglenastat + standard-of-care chemoimmunotherapy in previously untreated patients with KEAP1/NRF2-mutated, non-squamous metastatic NSCLC. A separate screening protocol (NCT04698681) is also available to assess KEAP1or NRF2 mutational status based on liquid biopsy NGS, which may be used to determine KEAPSAKE trial eligibility of patients whose mutational status is unknown.
Result(s):
Conclusion(s): Keywords: glutaminase, KEAPSAKE, telaglenastat
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In a recent article published in Molecular Cell, Dai et al. demonstrate that energy stress induced by a ketogenic diet or fasting can enhance checkpoint blockade therapy. Energy stress promotes lysosome-mediated degradation of the immunoinhibitory ligand programmed death-ligand 1 (PDL1) and upregulation of tumor interferon (IFN) responses.

Oncogenic mutations in KRAS drive common metabolic programmes that facilitate tumour survival, growth and immune evasion in colorectal carcinoma, non-small-cell lung cancer and pancreatic ductal adenocarcinoma. However, the impacts of mutant KRAS signalling on malignant cell programmes and tumour properties are also dictated by tumour suppressor losses and physiological features specific to the cell and tissue of origin. Here we review convergent and disparate metabolic networks regulated by oncogenic mutant KRAS in colon, lung and pancreas tumours, with an emphasis on co-occurring mutations and the role of the tumour microenvironment. Furthermore, we explore how these networks can be exploited for therapeutic gain.

Simultaneous measurement of surface proteins and gene expression within single cells using oligo-conjugated antibodies offers high-resolution snapshots of complex cell populations. Signal from oligo-conjugated antibodies is quantified by high-throughput sequencing and is highly scalable and sensitive. We investigated the response of oligo-conjugated antibodies towards four variables: concentration, staining volume, cell number at staining, and tissue. We find that staining with recommended antibody concentrations causes unnecessarily high background and amount of antibody used can be drastically reduced without loss of biological information. Reducing staining volume only affects antibodies targeting abundant epitopes used at low concentrations and is counteracted by reducing cell numbers. Adjusting concentrations increases signal, lowers background, and reduces costs. Background signal can account for a major fraction of total sequencing and is primarily derived from antibodies used at high concentrations. This study provides new insight into titration response and background of oligo-conjugated antibodies and offers concrete guidelines to improve such panels.

Pancreatic ductal adenocarcinoma is a lethal disease characterized by late diagnosis, propensity for early metastasis and resistance to chemotherapy. Little is known about the mechanisms that drive innate therapeutic resistance in pancreatic cancer. The ataxia-telangiectasia group D-associated gene (ATDC) is overexpressed in pancreatic cancer and promotes tumor growth and metastasis. Our study reveals that increased ATDC levels protect cancer cells from reactive oxygen species (ROS) via stabilization of nuclear factor erythroid 2-related factor 2 (NRF2). Mechanistically, ATDC binds to Kelch-like ECH-associated protein 1 (KEAP1), the principal regulator of NRF2 degradation, and thereby prevents degradation of NRF2 resulting in activation of a NRF2-dependent transcriptional program, reduced intracellular ROS and enhanced chemoresistance. Our findings define a novel role of ATDC in regulating redox balance and chemotherapeutic resistance by modulating NRF2 activity.

In lung cancer, enrichment of the lower airway microbiota with oral commensals commonly occurs and ex vivo models support that some of these bacteria can trigger host transcriptomic signatures associated with carcinogenesis. Here, we show that this lower airway dysbiotic signature was more prevalent in group IIIB-IV TNM stage lung cancer and is associated with poor prognosis, as shown by decreased survival among subjects with early stage disease (I-IIIA) and worse tumor progression as measured by RECIST scores among subjects with IIIB-IV stage disease. In addition, this lower airway microbiota signature was associated with upregulation of IL-17, PI3K, MAPK and ERK pathways in airway transcriptome, and we identified Veillonella parvula as the most abundant taxon driving this association. In a KP lung cancer model, lower airway dysbiosis with V. parvula led to decreased survival, increased tumor burden, IL-17 inflammatory phenotype and activation of checkpoint inhibitor markers.

Takahashi et al. (2020) conduct a focused CRISPR/Cas9 screen against NRF2 target and other redox regulatory genes in both 2D- and 3D-culture systems, uncovering a vulnerability of spheroid cancer cells deprived of extracellular matrix to undergo ferroptosis.

Targeting glycolysis has been considered therapeutically intractable owing to its essential housekeeping role. However, the context-dependent requirement for individual glycolytic steps has not been fully explored. We show that CRISPR-mediated targeting of glycolysis in T cells in mice results in global loss of Th17 cells, whereas deficiency of the glycolytic enzyme glucose phosphate isomerase (Gpi1) selectively eliminates inflammatory encephalitogenic and colitogenic Th17 cells, without substantially affecting homeostatic microbiota-specific Th17 cells. In homeostatic Th17 cells, partial blockade of glycolysis upon Gpi1 inactivation was compensated by pentose phosphate pathway flux and increased mitochondrial respiration. In contrast, inflammatory Th17 cells experience a hypoxic microenvironment known to limit mitochondrial respiration, which is incompatible with loss of Gpi1. Our study suggests that inhibiting glycolysis by targeting Gpi1 could be an effective therapeutic strategy with minimum toxicity for Th17-mediated autoimmune diseases, and, more generally, that metabolic redundancies can be exploited for selective targeting of disease processes.