Chimeric kinase ALK induces expression of NAMPT and selectively depends on this metabolic enzyme to sustain its own oncogenic function.

As we show in this study, NAMPT, the key rate-limiting enzyme in the salvage pathway, one of the three known pathways involved in NAD synthesis, is selectively over-expressed in anaplastic T-cell lymphoma carrying oncogenic kinase NPM1::ALK (ALK + ALCL). NPM1::ALK induces expression of the NAMPT-encoding gene with STAT3 acting as transcriptional activator of the gene. Inhibition of NAMPT affects ALK + ALCL cells expression of numerous genes, many from the cell-signaling, metabolic, and apoptotic pathways. NAMPT inhibition also functionally impairs the key metabolic and signaling pathways, strikingly including enzymatic activity and, hence, oncogenic function of NPM1::ALK itself. Consequently, NAMPT inhibition induces cell death in vitro and suppresses ALK + ALCL tumor growth in vivo. These results indicate that NAMPT is a novel therapeutic target in ALK + ALCL and, possibly, other similar malignancies. Targeting metabolic pathways selectively activated by oncogenic kinases to which malignant cells become "addicted" may become a novel therapeutic approach to cancer, alternative or, more likely, complementary to direct inhibition of the kinase enzymatic domain. This potential therapy to simultaneously inhibit and metabolically "starve" oncogenic kinases may not only lead to higher response rates but also delay, or even prevent, development of drug resistance, frequently seen when kinase inhibitors are used as single agents.

Targeting glutamine dependence through GLS1 inhibition suppresses ARID1A-inactivated clear cell ovarian carcinoma.

Alterations in components of the SWI/SNF chromatin-remodeling complex occur in ~20% of all human cancers. For example, ARID1A is mutated in up to 62% of clear cell ovarian carcinoma (OCCC), a disease currently lacking effective therapies. Here we show that ARID1A mutation creates a dependence on glutamine metabolism. SWI/SNF represses glutaminase (GLS1) and ARID1A inactivation upregulates GLS1. ARID1A inactivation increases glutamine utilization and metabolism through the tricarboxylic acid cycle to support aspartate synthesis. Indeed, glutaminase inhibitor CB-839 suppresses the growth of ARID1A mutant, but not wildtype, OCCCs in both orthotopic and patient-derived xenografts. In addition, glutaminase inhibitor CB-839 synergizes with immune checkpoint blockade anti-PDL1 antibody in a genetic OCCC mouse model driven by conditional Arid1a inactivation. Our data indicate that pharmacological inhibition of glutaminase alone or in combination with immune checkpoint blockade represents an effective therapeutic strategy for cancers involving alterations in the SWI/SNF complex such as ARID1A mutations.

Deciphering the Duality of Clock and Growth Metabolism in a Cell Autonomous System Using NMR Profiling of the Secretome.

Oscillations in circadian metabolism are crucial to the well being of organism. Our understanding of metabolic rhythms has been greatly enhanced by recent advances in high-throughput systems biology experimental techniques and data analysis. In an in vitro setting, metabolite rhythms can be measured by time-dependent sampling over an experimental period spanning one or more days at sufficent resolution to elucidate rhythms. We hypothesized that cellular metabolic effects over such a time course would be influenced by both oscillatory and circadian-independent cell metabolic effects. Here we use nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling of mammalian cell culture media of synchronized U2 OS cells containing an intact transcriptional clock. The experiment was conducted over 48 h, typical for circadian biology studies, and samples collected at 2 h resolution to unravel such non-oscillatory effects. Our data suggest specific metabolic activities exist that change continuously over time in this settting and we demonstrate that the non-oscillatory effects are generally monotonic and possible to model with multivariate regression. Deconvolution of such non-circadian persistent changes are of paramount importance to consider while studying circadian metabolic oscillations.

Emerging Concepts in the Analysis of Transcriptional Targets of the MYC Oncoprotein: Are the Targets Targetable?

Activation of the MYC oncoprotein is among the most ubiquitous events in human cancer. MYC functions in part as a sequence-specific regulator of transcription. Although early searches for direct downstream target genes that explain MYC's potent biological activity were met with enthusiasm, the postgenomic decade has brought the realization that MYC regulates the transcription of not just a manageably small handful of target genes but instead up to 15% of all active loci. As the dust has begun to settle, two important concepts have emerged that reignite hope that understanding MYC's downstream targets might still prove valuable for defining critical nodes for therapeutic intervention in cancer patients. First, it is now clear that MYC target genes are not a random sampling of the cellular transcriptome but instead fall into specific, critical biochemical pathways such as metabolism, chromatin structure, and protein translation. In retrospect, we should not have been surprised to discover that MYC rewires cell physiology in a manner designed to provide the tumor cell with greater biosynthetic properties. However, the specific details that have emerged from these studies are likely to guide the development of new clinical tools and strategies. This raises the second concept that instills renewed optimism regarding MYC target genes. It is now clear that not all MYC target genes are of equal functional relevance. Thus, it may be possible to discern, from among the thousands of potential MYC target genes, those whose inhibition will truly debilitate the tumor cell. In short, targeting the targets may ultimately be a realistic approach after all.

Nuclear MYC protein overexpression is an early alteration in human prostate carcinogenesis.

The MYC onco-protein is a transcription factor that regulates cell proliferation, metabolism, protein synthesis, mitochondrial function and stem cell renewal. A region on chromosome 8q24 encompassing the MYC locus is amplified in prostate cancer, but this occurs mostly in advanced disease suggesting that MYC alterations occur late in prostate cancer. In contrast, MYC mRNA is elevated in most prostate cancers, even those of relatively low stage and grade (eg Gleason score 6) suggesting that MYC plays a role in initiation. However, since MYC protein levels are tightly regulated, elevated MYC mRNA does not necessarily imply elevated MYC protein. Thus, it is critical to determine whether MYC protein is elevated in human prostate cancer, and if so, at what stage of the disease this elevation occurs. Prior studies of MYC protein localization have been hampered by lack of suitable antibodies and controls. We utilized a new anti-MYC antibody coupled with genetically defined control experiments to localize MYC protein within human tissue microarrays consisting of normal, atrophy, PIN, primary adenocarcinoma, and metastatic adenocarcinoma. Nuclear overexpression of MYC protein occurred frequently in luminal cells of PIN, as well as in most primary carcinomas and metastatic disease. MYC protein did not correlate with gain of 8q24, suggesting alternative mechanisms for MYC overexpression. These results provide evidence that upregulation of nuclear MYC protein expression is a highly prevalent and early change in prostate cancer and suggest that increased nuclear MYC may be a critical oncogenic event driving human prostate cancer initiation and progression.