Frequency of weight and body composition increases in advanced non-small cell lung cancer patients during first line therapy.

BACKGROUND: The primary objective of this study was to assess the frequency of body composition increases and their relationships to changes in body weight in two cohorts of real world, treatment-naïve, advanced non-small cell lung cancer (NSCLC) patients. One cohort received the current standard of care (CSOC), which consisted of immunotherapy and newer chemotherapy regimens, and the other cohort was treated with the former standard of care (FSOC), consisting only of older platinum-containing regimens. METHODS: CSOC (n = 106) and FSOC (n = 88) cohorts of advanced NSCLC patients were included in this study. Weights were collected at each clinical visit, and body composition analysis from routine chest computed tomography via automated segmentation software assessed at baseline and at 6 and 12 weeks. Standard statistical methods were used to calculate relationships between changes in weight and in body composition. RESULTS: The CSOC cohort contained 106 stage IV NSCLC patients treated between 16/12/2014 and 22/10/2020 while the FSOC cohort contained 88 stage III/IV NSCLC patients treated between 16/6/2006 and 18/11/2014. While each cohort exhibited decreases in median weight, body mass index (BMI), mean skeletal muscle index (SMI) and subcutaneous adipose tissue index (SATI) at the 6 and 12 week time points, a subset of patients experienced increases in these parameters. Using a threshold of ≥2.5% increase for weight, BMI, SMI, and SATI at the 12 week time point, both cohorts showed similar (20.5% and 27.3%) increases in these parameters. With a cut point of ≥5% increase at 12 weeks follow-up, 8.0% to 25.0% of the patients gained ≥5% in weight, BMI, SMI and SATI. Comparing these results in each cohort showed no significant differences. Pearson coefficients for weight change related to changes in SMI and SATI at 6 and 12 weeks ranged from 0.31 to 0.58 with all P values <0.02. Pearson coefficients for weight change at 12 weeks related to changes in VATI and IMATI ranged from 0.26 to 0.47 with all P values <0.05. Comparison of Pearson coefficients for each cohort showed no significant differences. CONCLUSIONS: Although decreases in median weight, BMI, SMI and SATI were observed in both cohorts, similar percentage of patients in each cohort experienced increases in these parameters. These findings, plus the positive correlations between longitudinal measurements of weight, muscle mass and adipose tissue, indicate that weight gain in these patients involves increases in both muscle mass and adipose tissue. Upon validation, these findings could have implications for clinical trial design and for translational research in cancer cachexia.

Cancer Cachexia in STK11/LKB1 -mutated NSCLC is Dependent on Tumor-secreted GDF15.

Cachexia is a wasting syndrome comprised of adipose, muscle, and weight loss observed in cancer patients. Tumor loss-of-function mutations in STK11/LKB1 , a regulator of the energy sensor AMP-activated protein kinase, induce cancer cachexia (CC) in preclinical models and are associated with cancer-related weight loss in NSCLC patients. Here we characterized the relevance of the NSCLC-associated cachexia factor growth differentiation factor 15 (GDF15) in several patient-derived and genetically engineered STK11/LKB1 -mutant NSCLC cachexia lines. Both tumor mRNA expression and serum concentrations of tumor-derived GDF15 were significantly elevated in multiple mice transplanted with patient-derived STK11/LKB1 -mutated NSCLC lines. GDF15 neutralizing antibody administered to mice transplanted with patient- or mouse-derived STK11/LKB1 -mutated NSCLC lines suppressed cachexia-associated adipose loss, muscle atrophy, and changes in body weight. The silencing of GDF15 in multiple human NSCLC lines was also sufficient to eliminate in vivo circulating GDF15 levels and abrogate cachexia induction, suggesting that tumor and not host tissues represent a key source of GDF15 production in these cancer models. Finally, reconstitution of wild-type STK11/LKB1 in a human STK11/LKB1 loss-of-function NSCLC line that normally induces cachexia in vivo correlated with the absence of tumor-secreted GDF15 and rescue from the cachexia phenotype. The current data provide evidence for tumor-secreted GDF15 as a conduit and a therapeutic target through which NSCLCs with STK11/LKB1 loss-of-function mutations promote cachexia-associated wasting.

Nicotinamide N-methyltransferase regulates hepatic nutrient metabolism through Sirt1 protein stabilization.

Nicotinamide N-methyltransferase (Nnmt) methylates nicotinamide, a form of vitamin B3, to produce N(1)-methylnicotinamide (MNAM). Nnmt has emerged as a metabolic regulator in adipocytes, but its role in the liver, the tissue with the strongest Nnmt expression, is not known. In spite of its overall high expression, here we find that hepatic expression of Nnmt is highly variable and correlates with multiple metabolic parameters in mice and humans. Further, we find that suppression of hepatic Nnmt expression in vivo alters glucose and cholesterol metabolism and that the metabolic effects of Nnmt in the liver are mediated by its product MNAM. Supplementation of high-fat diet with MNAM decreases serum and liver cholesterol and liver triglycerides levels in mice. Mechanistically, increasing Nnmt expression or MNAM levels stabilizes sirtuin 1 protein, an effect that is required for their metabolic benefits. In summary, we describe here a novel regulatory pathway for vitamin B3 that could provide a new opportunity for metabolic disease therapy.

Hypomorphic mutation of PGC-1beta causes mitochondrial dysfunction and liver insulin resistance.

PGC-1beta is a transcriptional coactivator that potently stimulates mitochondrial biogenesis and respiration of cells. Here, we have generated mice lacking exons 3 to 4 of the Pgc-1beta gene (Pgc-1beta(E3,4-/E3,4-) mice). These mice express a mutant protein that has reduced coactivation activity on a subset of transcription factors, including ERRalpha, a major target of PGC-1beta in the induction of mitochondrial gene expression. The mutant mice have reduced expression of OXPHOS genes and mitochondrial dysfunction in liver and skeletal muscle as well as elevated liver triglycerides. Euglycemic-hyperinsulinemic clamp and insulin signaling studies show that PGC-1beta mutant mice have normal skeletal muscle response to insulin but have hepatic insulin resistance. These results demonstrate that PGC-1beta is required for normal expression of OXPHOS genes and mitochondrial function in liver and skeletal muscle. Importantly, these abnormalities do not cause insulin resistance in skeletal muscle but cause substantially reduced insulin action in the liver.

TLR4 links innate immunity and fatty acid-induced insulin resistance.

TLR4 is the receptor for LPS and plays a critical role in innate immunity. Stimulation of TLR4 activates proinflammatory pathways and induces cytokine expression in a variety of cell types. Inflammatory pathways are activated in tissues of obese animals and humans and play an important role in obesity-associated insulin resistance. Here we show that nutritional fatty acids, whose circulating levels are often increased in obesity, activate TLR4 signaling in adipocytes and macrophages and that the capacity of fatty acids to induce inflammatory signaling in adipose cells or tissue and macrophages is blunted in the absence of TLR4. Moreover, mice lacking TLR4 are substantially protected from the ability of systemic lipid infusion to (a) suppress insulin signaling in muscle and (b) reduce insulin-mediated changes in systemic glucose metabolism. Finally, female C57BL/6 mice lacking TLR4 have increased obesity but are partially protected against high fat diet-induced insulin resistance, possibly due to reduced inflammatory gene expression in liver and fat. Taken together, these data suggest that TLR4 is a molecular link among nutrition, lipids, and inflammation and that the innate immune system participates in the regulation of energy balance and insulin resistance in response to changes in the nutritional environment.

Complex role of the vitamin D receptor and its ligand in adipogenesis in 3T3-L1 cells.

The vitamin D receptor (VDR) and its ligand 1,25-OH2-VD3 (calcitriol) play an essential role in mineral homeostasis in mammals. Interestingly, the VDR is expressed very early in adipogenesis in 3T3-L1 cells, suggesting that the VDR signaling pathway may play a role in adipocyte biology and function. Indeed, it has been known for a number of years that calcitriol is a potent inhibitor of adipogenesis in this model but with no clear mechanism identified. In this study, we have further defined the molecular mechanism by which the unliganded VDR and calcitriol-liganded VDR regulate adipogenesis. In the presence of calcitriol, the VDR blocks adipogenesis by down-regulating both C/EBPbeta mRNA expression and C/EBPbeta nuclear protein levels at a critical stage of differentiation. In addition, calcitriol allows for the up-regulation of the recently described C/EBPbeta corerepressor, ETO, which would further inhibit the action of any remaining C/EBPbeta, whose action is required for adipogenesis. In contrast, in the absence of calcitriol, the unliganded VDR appears necessary for lipid accumulation, since knock-down of the VDR using siRNA both delays and prevents this process. Taken together, these data support the notion that the intracellular concentrations of calcitriol can play an important role in either promoting or inhibiting adipogenesis via the VDR and the transcriptional pathways that it targets. Further examination of this hypothesis in vivo may shed new light on the biology of adipogenesis.

Suppressor of cytokine signaling 3 is a physiological regulator of adipocyte insulin signaling.

Many proinflammatory cytokines and hormones have been demonstrated to be involved in insulin resistance. However, the molecular mechanisms whereby these cytokines and hormones inhibit insulin signaling are not completely understood. We observed that several cytokines and hormones that induce insulin resistance also stimulate SOCS3 expression in 3T3-L1 adipocytes and that SOCS3 mRNA is increased in adipose tissue of obese/diabetic mice. We then hypothesized that SOCS3 may mediate cytokine- and hormone-induced insulin resistance. By using SOCS3-deficient adipocytes differentiated from mouse embryonic fibroblasts, we found that SOCS3 deficiency increases insulin-stimulated IRS1 and IRS2 phosphorylation, IRS-associated phosphatidylinositol 3-kinase activity, and insulin-stimulated glucose uptake. Moreover, lack of SOCS3 substantially limits the inhibitory effects of tumor necrosis factor-alpha to suppress IRS1 and IRS2 tyrosine phosphorylation, phosphatidylinositol 3-kinase activity, and glucose uptake in adipocytes. The ameliorated insulin signaling in SOCS3-deficient adipocytes is mainly due to the suppression of tumor necrosis factor-alpha-induced IRS1 and IRS2 protein degradation. Therefore, our data suggest that endogenous SOCS3 expression is a key determinant of basal insulin signaling and is an important molecular mediator of cytokine-induced insulin resistance in adipocytes. We conclude that SOCS3 plays an important role in mediating insulin resistance and may be an excellent target for therapeutic intervention in insulin resistance and type II diabetes.

Decreased expression of peroxisome proliferator activated receptor gamma in cftr-/- mice.

Some of the pathological manifestations of cystic fibrosis are in accordance with an impaired expression and/or activity of PPARgamma. We hypothesized that PPARgamma expression is altered in tissues lacking the normal cystic fibrosis transmembrane regulator protein (CFTR). PPARgamma mRNA levels were measured in colonic mucosa, ileal mucosa, adipose tissue, lung, and liver from wild-type and cftr-/- mice by quantitative RT-PCR. PPARgamma expression was decreased twofold in CFTR-regulated tissues (colon, ileum, and lung) from cftr-/- mice compared to wild-type littermates. In contrast, no differences were found in fat and liver. Immunohistochemical analysis of PPARgamma in ileum and colon revealed a predominantly nuclear localization in wild-type mucosal epithelial cells while tissues from cftr-/- mice showed a more diffuse, lower intensity labeling. A significant decrease in PPARgamma expression was confirmed in nuclear extracts of colon mucosa by Western blot analysis. In addition, binding of the PPARgamma/RXR heterodimer to an oligonucletotide containing a peroxisome proliferator responsive element (PPRE) was also decreased in colonic mucosa extracts from cftr-/- mice. Treatment of cftr-/- mice with the PPARgamma ligand rosiglitazone restored both the nuclear localization and binding to DNA, but did not increase RNA levels. We conclude that PPARgamma expression in cftr-/- mice is downregulated at the RNA and protein levels and its function diminished. These changes may be related to the loss of function of CFTR and may be relevant to the pathogenesis of metabolic abnormalities associated with cystic fibrosis in humans.

Melanin-concentrating hormone receptor 1 activates extracellular signal-regulated kinase and synergizes with G(s)-coupled pathways.

Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that plays a key role in energy homeostasis. Like many neuropeptides, it signals through two G protein-coupled receptors. MCH receptor 1 (MCHR1) is the sole receptor expressed in rodents and couples to G(i) and G(q) proteins. Little is known about the intracellular pathways engaged by MCH and its receptor. Using HEK293 cells stably expressing MCHR1, we demonstrate that MCH, acting through MCHR1, antagonizes the action of forskolin, an adenylate cyclase activator that increases intracellular levels of cAMP. MCH also inhibits cAMP induction by the G(s)-coupled beta-adrenergic receptor. Activation of either the G(i)- or G(s)-dependent pathway typically results in ERK phosphorylation in HEK293 cells. In contrast to opposing actions on cAMP synthesis, simultaneous MCH and forskolin treatment results in synergistic activation of ERK. This synergy proceeds through pertussis toxin-independent pathways and requires several enzymatic activities such as protein kinase A, protein kinase C, phospholipase C, and Src kinase. Finally, we provide evidence that such positive interactions are not limited to cell lines but can also be observed in the brain.