Highlights d Kinase inhibitors (KIs) and biguanides synergistically target cancer cells d mTORC1/4E-BP axis regulates aspartate, asparagine, and serine biosynthetic enzymes d 4E-BPs and HIF-1a determine responses to KI/biguanide combinations d Cancer cell metabolic plasticity limits efficacy of the KI/ biguanide combinations

PRDM15 is a key regulator of metabolism critical to sustain B-cell lymphomagenesis Slim Mzoughi et al. # PRDM (PRDI-BF1 and RIZ homology domain containing) family members are sequencespecific transcriptional regulators involved in cell identity and fate determination, often dysregulated in cancer. The PRDM15 gene is of particular interest, given its low expression in adult tissues and its overexpression in B-cell lymphomas. Despite its well characterized role in stem cell biology and during early development, the role of PRDM15 in cancer remains obscure. Herein, we demonstrate that while PRDM15 is largely dispensable for mouse adult somatic cell homeostasis in vivo, it plays a critical role in B-cell lymphomagenesis. Mechanistically, PRDM15 regulates a transcriptional program that sustains the activity of the PI3K/AKT/mTOR pathway and glycolysis in B-cell lymphomas. Abrogation of PRDM15 induces a metabolic crisis and selective death of lymphoma cells. Collectively, our data demonstrate that PRDM15 fuels the metabolic requirement of B-cell lymphomas and validate it as an attractive and previously unrecognized target in oncology.

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Highlights Canagliflozin constrains cell proliferation in the absence of glucose. Canagliflozin modulates mitochondrial respiration. Canagliflozin impairs glutamine-mediated anaplerosis through the citric acid cycle. Canagliflozin mediates antiproliferative response through inhibition of glutamine metabolism.

Notwithstanding that metabolic perturbations and dysregulated protein synthesis are salient features of cancer, the mechanism underlying coordination of cellular energy balance with mRNA translation (which is the most energy consuming process in the cell) is poorly understood. In this review, we focus on recently emerging insights in the molecular underpinnings of the cross-talk between oncogenic kinases, translational apparatus and cellular energy metabolism. In particular, we focus on the central signaling nodes that regulate these processes (e.g. the mechanistic/mammalian target of rapamycin MTOR) and the potential implications of these findings on improving the anti-neoplastic efficacy of oncogenic kinase inhibitors.

Mutations in genes encoding cytochrome c oxidase (mitochondrial complex IV) subunits and assembly factors [e.g., synthesis of cytochrome c oxidase 2 (SCO2)] are linked to severe metabolic syndromes. Notwithstanding that SCO2 is under transcriptional control of tumor suppressor p53, the role of mitochondrial complex IV dysfunction in cancer metabolism remains obscure. Herein, we demonstrate that the loss of SCO2 in HCT116 colorectal cancer cells leads to significant metabolic and signaling perturbations. Specifically, abrogation of SCO2 increased NAD+ regenerating reactions and decreased glucose oxidation through citric acid cycle while enhancing pyruvate carboxylation. This was accompanied by a reduction in amino acid levels and the accumulation of lipid droplets. In addition, SCO2 loss resulted in hyperactivation of the insulin‐like growth factor 1 receptor (IGF1R)/AKT axis with paradoxical downregulation of mTOR signaling, which was accompanied by increased AMP‐activated kinase activity. Accordingly, abrogation of SCO2 expression appears to increase the sensitivity of cells to IGF1R and AKT, but not mTOR inhibitors. Finally, the loss of SCO2 was associated with reduced proliferation and enhanced migration of HCT116 cells. Collectively, herein we describe potential adaptive signaling and metabolic perturbations triggered by mitochondrial complex IV dysfunction.

Ultrasound and microbubbles (USMB) is a promising strategy for cancer therapy. USMB can induce a variety of effects on cells including transient formation of plasma membrane pores (sonoporation) and enhanced endocytosis, which enhance drug delivery, and can also lead to enhanced cell death. However, the outcomes of USMB on cell physiology are heterogeneous, in that USMB elicits cell death in a proportion of cells while exerting minimal effects on others. This suggests that mechanisms of adaptation following USMB allow some cells to survive and/or proliferate. The molecular mechanisms of adaptation to USMB-induced stress remain poorly understood, thus potentially hindering broad therapeutic applications of USMB. Herein, we used several triple negative breast cancer cells to study the effect of USMB-induced metabolite stress and the role of AMPK as a response to this stress. We found that USMB alters steady-state levels of amino acids, glycolytic intermediates, and citric acid cycle intermediates. USMB treatment acutely reduces ATP levels and stimulates AMP-activated protein kinase (AMPK) phosphorylation and activation. Further, AMPK is required to restore ATP levels in cells that survived the initial insult and support cell proliferation post-USMB treatment. These results suggest that AMPK and metabolic perturbations are likely determinants of the anti-neoplastic efficacy of USMB treatment.

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