The ERK and JNK pathways in the regulation of metabolic reprogramming.

Most tumor cells reprogram their glucose metabolism as a result of mutations in oncogenes and tumor suppressors, leading to the constitutive activation of signaling pathways involved in cell growth. This metabolic reprogramming, known as aerobic glycolysis or the Warburg effect, allows tumor cells to sustain their fast proliferation and evade apoptosis. Interfering with oncogenic signaling pathways that regulate the Warburg effect in cancer cells has therefore become an attractive anticancer strategy. However, evidence for the occurrence of the Warburg effect in physiological processes has also been documented. As such, close consideration of which signaling pathways are beneficial targets and the effect of their inhibition on physiological processes are essential. The MAPK/ERK and MAPK/JNK pathways, crucial for normal cellular responses to extracellular stimuli, have recently emerged as key regulators of the Warburg effect during tumorigenesis and normal cellular functions. In this review, we summarize our current understanding of the roles of the ERK and JNK pathways in controlling the Warburg effect in cancer and discuss their implication in controlling this metabolic reprogramming in physiological processes and opportunities for targeting their downstream effectors for therapeutic purposes.Brunel Research Initiative & Enterprise Fund, Brunel University of London (to CB), Kay Kendall Leukemia Fund (KKL443) (to CB), 250 Great Minds Fellowship, University of Leeds (to SP), AMMF Cholangiocarcinoma Charity (to SP and PMC), and Bloodwise (17014) (to SP and CB)

The BRAF Inhibitor Vemurafenib Activates Mitochondrial Metabolism and Inhibits Hyperpolarized Pyruvate-Lactate Exchange in BRAF-Mutant Human Melanoma Cells.

Understanding the impact of BRAF signaling inhibition in human melanoma on key disease mechanisms is important for developing biomarkers of therapeutic response and combination strategies to improve long-term disease control. This work investigates the downstream metabolic consequences of BRAF inhibition with vemurafenib, the molecular and biochemical processes that underpin them, their significance for antineoplastic activity, and potential as noninvasive imaging response biomarkers. 1 H NMR spectroscopy showed that vemurafenib decreases the glycolytic activity of BRAF-mutant (WM266.4 and SKMEL28) but not BRAF WT (CHL-1 and D04) human melanoma cells. In WM266.4 cells, this was associated with increased acetate, glycine, and myo-inositol levels and decreased fatty acyl signals, while the bioenergetic status was maintained. 13 C NMR metabolic flux analysis of treated WM266.4 cells revealed inhibition of de novo lactate synthesis and glucose utilization, associated with increased oxidative and anaplerotic pyruvate carboxylase mitochondrial metabolism and decreased lipid synthesis. This metabolic shift was associated with depletion of hexokinase 2, acyl-CoA dehydrogenase 9, 3-phosphoglycerate dehydrogenase, and monocarboxylate transporters (MCT) 1 and 4 in BRAF-mutant but not BRAF WT cells and, interestingly, decreased BRAF-mutant cell dependency on glucose and glutamine for growth. Further, the reduction in MCT1 expression observed led to inhibition of hyperpolarized 13 C-pyruvate-lactate exchange, a parameter that is translatable to in vivo imaging studies, in live WM266.4 cells. In conclusion, our data provide new insights into the molecular and metabolic consequences of BRAF inhibition in BRAF-driven human melanoma cells that may have potential for combinatorial therapeutic targeting as well as noninvasive imaging of response. Mol Cancer Ther; 15(12); 2987-99. ©2016 AACR

Influence of salinomycin treatment on division and movement of individual cancer cells cultured in normoxia or hypoxia evaluated with time-lapse digital holographic microscopy

Most studies on new cancer drugs are based on population-derived data, where the absence of response of a small population may pass unnoticed. Thus, individual longitudinal tracking of cells is important for the future development of efficient cancer treatments. We have used digital holographic microscopy to track individual JIMT-1 human breast cancer cells and L929 mouse fibroblast cultivated in normoxia or hypoxia. In addition, JIMT-1 cells were treated with salinomycin, a cancer stem cell targeting compound. Three-day time-lapse movies were captured and individual cells were analysed with respect to cell division (cell cycle length) and cell movement. Comparing population-doubling time derived from population-based growth curves and individual cell cycle time data from time-lapse movies show that the former hide a sub-population of dividing cells. Salinomycin treatment increased the motility of cells, however, this motility did not result in an increased distant migration i.e. the cells increased their local movement. MCF-7 breast cancer cells showed similar motility behaviour as salinomycin-treated JIMT-1 cells. We suggest that combining features, such as motility and migration, can be used to distinguish cancer cells with mesenchymal (JIMT-1) and epithelial (MCF-7) features. The data clearly emphasize the importance of longitudinal cell tracking to understand the biology of individual cells under different conditions