Screening of metabolic modulators identifies new strategies to target metabolic reprogramming in melanoma.

The prognosis of metastatic melanoma remains poor due to de novo or acquired resistance to immune and targeted therapies. Previous studies have shown that melanoma cells have perturbed metabolism and that cellular metabolic pathways represent potential therapeutic targets. To support the discovery of new drug candidates for melanoma, we examined 180 metabolic modulators, including phytochemicals and anti-diabetic compounds, for their growth-inhibitory activities against melanoma cells, alone and in combination with the BRAF inhibitor vemurafenib. Two positive hits from this screen, 4-methylumbelliferone (4-MU) and ursolic acid (UA), were subjected to validation and further characterization. Metabolic analysis showed that 4-MU affected cellular metabolism through inhibition of glycolysis and enhanced the effect of vemurafenib to reduce the growth of melanoma cells. In contrast, UA reduced mitochondrial respiration, accompanied by an increase in the glycolytic rate. This metabolic switch potentiated the growth-inhibitory effect of the pyruvate dehydrogenase kinase inhibitor dichloroacetate. Both drug combinations led to increased production of reactive oxygen species, suggesting the involvement of oxidative stress in the cellular response. These results support the potential use of metabolic modulators for combination therapies in cancer and may encourage preclinical validation and clinical testing of such treatment strategies in patients with metastatic melanoma.

Inhibition of retinoic acid receptor ß signaling confers glycolytic dependence and sensitization to dichloroacetate in melanoma cells.

Dysregulation of metabolism during melanoma progression is tightly associated with the acquisition of genetic and epigenetic alterations in regulators of metabolic pathways. Retinoic acid receptor beta (RARß) is epigenetically silenced in a large proportion of melanomas, but a link between RARß and metabolic rewiring of melanoma has not been established. Here, we show that in primary human melanocytes, all-trans retinoic acid (a RARß agonist) induced growth inhibition accompanied by a decrease in both glycolytic and oxidative metabolism, whereas selective inhibition of RARß led to an increase in the basal glycolytic rate and increased sensitivity to inhibition of glycolysis. In melanoma cells, inhibition of RARß promoted lower mitochondrial respiration and higher glycolytic activity, which led to energetic stress and activation of the energy sensor AMP-activated protein kinase. This metabolic shift increased the sensitivity to both glycolytic inhibition and stimulation of mitochondrial metabolism with dichloroacetate, an inhibitor of pyruvate dehydrogenase kinase. In melanoma cells harboring the BRAFV600E mutation, RARß activation antagonized the effect of the BRAF inhibitor PLX4032 (vemurafenib). Collectively, these data suggest that RARß signaling is involved in regulating cellular metabolism in melanoma and may provide a potential target in combination treatment strategies.

Multidisciplinary nutritional support for undernutrition in nursing home and home-care: A cluster randomized controlled trial.

OBJECTIVE: To assess the effect of multidisciplinary nutritional support for undernutrition in older adults in nursing home and home-care identified with the validated Eating Validation Scheme (EVS). METHODS: An 11 wk cluster randomized trial with a home-care (3 clusters) or nursing home (3 clusters) setting as the unit of randomization. Before starting the study, a train-the-trainer course was performed to educate the nutrition coordinators. In addition to the nutrition coordinator, the participants assigned to the intervention group strategy received multidisciplinary nutrition support. Focus was on treatment of the potentially modifiable nutritional risk factors identified with the EVS, by involving the physiotherapist, registered dietitian, and occupational therapist, as relevant and independent of the municipality's ordinary assessment and referral system. Outcome parameters were quality of life (by means of EuroQol-5D-3L), physical performance (30-seconds chair stand), nutritional status (weight and hand-grip strength), oral care, fall incidents, hospital admissions, rehabilitation stay, moving to nursing homes (participants from home-care), and mortality. RESULTS: Respectively, 55 (46 from 2 home-care clusters) and 40 (18 from 1 home-care cluster) were identified with the EVS and comprised the intervention and control group. A difference after 11 wk in quality of life (0.758 [0.222] versus 0.534 [0.355], P = 0.001), 30-seconds chair stand (47% versus 17% improved, P = 0.005) and oral care (1.1 [0.3] versus 1.3 [0.5], P = 0.021) was observed. There was a almost significant difference in mortality (2% versus 13%, P = 0.079). CONCLUSIONS: Multidisciplinary nutritional support in older adults in nursing home and home-care could have a positive effect on quality of life, muscle strength, and oral care.

Study protocol: cost-effectiveness of multidisciplinary nutritional support for undernutrition in older adults in nursing home and home-care: cluster randomized controlled trial.

BACKGROUND: Older adults in nursing home and home-care are a particularly high-risk population for weight loss or poor nutrition. One negative consequence of undernutrition is increased health care costs. Several potentially modifiable nutritional risk factors increase the likelihood of weight loss or poor nutrition. Hence a structured and multidisciplinary approach, focusing on the nutritional risk factors and involving e.g. dieticians, occupational therapists, and physiotherapist, may be necessary to achieve benefits. Up till now a few studies have been done evaluating the cost-effectiveness of nutritional support among undernourished older adults and none of these have used such a multidisciplinary approach. METHODS: An 11 week cluster randomized trial to assess the cost-effectiveness of multidisciplinary nutritional support for undernutrition in older adults in nursing home and home-care, identified by screening with the Eating validation Scheme. Before start of the study there will be performed a train-the-trainer intervention involving educated nutrition coordinators.In addition to the nutrition coordinator, the participants assigned to the intervention group strategy will receive multidisciplinary nutrition support. Focus will be on treatment of the potentially modifiable nutritional risk factors identified by screening, by involving physiotherapist, registered dietician, and occupational therapist, as relevant and independent of the municipality's ordinary assessment and referral system.The primary outcome parameter will be change in quality of life (by means of Euroquol-5D-3L). Secondary outcomes will be: physical performance (chair stand), nutritional status (weight, Body Mass Index and hand-grip strength), oral care, fall incidents, hospital admissions, rehabilitation stay, moving to nursing homes (for participants from home-care), use of social services and mortality.An economic evaluation will be conducted to evaluate the cost-effectiveness of the multidisciplinary support.Furthermore, interviews with nursing home and home-care management, nursing staff and nutrition coordinators in both the control and intervention groups, participants in the intervention group and the involved multidisciplinary team will be performed. CONCLUSION: In this study we will evaluate in a randomized controlled trial whether multidisciplinary nutritional support is cost-effective, in undernourished older adults in home-care and nursing home and contribute to important research. TRIAL REGISTRATION: ClinicalTrials.gov 2013 NCT01873456.

Dietary xylooligosaccharide downregulates IFN-γ and the low-grade inflammatory cytokine IL-1ß systemically in mice.

Dietary carbohydrates improve growth conditions for distinct populations of bacteria that may affect mucosal and systemic immunity. In this study, we fed in a parallel experiment a 10% xylooligosaccharide (XOS)-supplemented diet or a control diet to 2 groups of male C57BL/6NTac mice for 10 wk from weaning. We found that the XOS diet significantly increased Bifidobacterium throughout the intestine compared with control-fed mice, with the highest proportions found in the ileum after XOS feeding (P < 0.001). In the intestinal epithelium, most innate immune-related genes were unaffected by XOS feeding, whereas expression of interleukin 1ß (Il1ß) (P < 0.01) and interferon γ (Ifnγ) (P < 0.05) was significantly less in blood from XOS-fed mice than from control-fed mice. In vitro treatment of blood with propionate significantly decreased Il1ß (P < 0.01), Ifnγ (P < 0.01), and interleukin 18 (Il18) (P < 0.001) expression, supporting our hypothesis that increased production of short-chain fatty acids (SCFAs) in the gut, which are transported across the intestine and into the systemic compartments, results in downregulation of low-grade inflammatory cytokines. The defensin regenerating islet-derived protein 3γ (RegIIIγ) was significantly more highly expressed in the small intestine (P < 0.01) in XOS-fed mice compared with control-fed mice, suggesting only minor contact between bifidobacteria and epithelial cells. In support of this, the SCFA-induced sodium/hydrogen exchanger isoform 3 expression tended to be greater in the XOS group than in the control group (P = 0.06), indicating an indirect SCFA-mediated antiinflammatory effect of XOS. In conclusion, XOS feeding decreases systemic inflammation, and this effect is most likely caused by higher SCFA concentrations as a result of an increased bifidobacterial saccharolytic fermentation in the entire gut and not only in the large intestine.

Functional significance of metastasis-inducing S100A4(Mts1) in tumor-stroma interplay.

Causal implication of S100A4 in inducing metastases was convincingly shown previously. However, the mechanisms that associate S100A4 with tumor progression are not well understood. S100A4 protein, as a typical member of the S100 family, exhibits dual, intracellular and extracellular, functions. This work is focused on the extracellular function of S100A4, in particular its involvement in tumor-stroma interplay in VMR (mouse adenocarcinoma cell line) tumor cells, which exhibit stroma-dependent metastatic phenotype. We demonstrated the reciprocal influence of tumor and stroma cells where tumor cells stimulate S100A4 secretion from fibroblasts in culture. In turn, extracellular S100A4 modifies the cytoskeleton and focal adhesions and triggers several other events in tumor cells. We found stabilization of the tumor suppressor protein p53 and modulation of its function. In particular, extracellular S100A4 down-regulates the pro-apoptotic bax and the angiogenesis inhibitor thrombospondin-1 genes. For the first time, we demonstrate here that the S100A4 protein added to the extracellular space strongly stimulates proteolytic activity of VMR cells. This activity most probably is associated with matrix metalloproteinases and, in particular, with matrix metalloproteinase-13. Finally, the application of the recombinant S100A4 protein confers stroma-independent metastatic phenotype on VMR tumor cells. In conclusion, our results indicate that metastasis-inducing S100A4 protein plays a pivotal role in the tumor-stroma environment. S100A4 released either by tumor or stroma cells triggers pro-metastatic cascades in tumor cells.