Current Pharmaceutical Design - Volume 23, Issue 25, 2017

Background: AMP-activated protein kinase (AMPK) is a protein kinase that maintains homeostasis in cells and organs. As a master regulator of metabolism, AMPK coordinates many metabolic reactions. AMPK is a key factor in diabetes and metabolic syndrome associated with dysregulation of the metabolic status. Recently, AMPK has also attracted attention as a tumor suppressor. The aim of this article is to discuss about the role of AMPK in diabetes as well as cancer and to evaluate its effectiveness in treatment and prevention of these diseases. Method: We reviewed studies of signaling mechanism involving AMPK and research on the role of AMPK in human disease including diabetes and cancer. In particular, we focused our attention on clinical trials about cancer treatment and prevention targeting AMPK. Results: Many experimental studies reported the relation of AMPK and various metabolic reactions, mainly regulating energy homeostasis. Recent studies showed effect of AMPK on arrest of cell cycle as well as suppression of inflammation, which are important factors for carcinogenesis. Although some clinical studies investigated cancer treatment and prevention targeting AMPK, the effective yields in clinical trial have been limited. Conclusion: AMPK activation as represented by metformin showed to improve disorders associated with diabetes and metabolic syndrome and became a well-established treatment strategy for these diseases. The increasing evidence suggests that AMPK is a promising target in the treatment and prevention of cancer. Further investigation including long-term clinical trials with large sample size is needed.

Background: The gp130 cytokine, oncostatin M (OSM), serves several physiological and pathological functions. At the molecular level, OSM can directly or indirectly participate in tumorigenesis and insulin resistance development. Although OSM was initially found to be anti-proliferative in tumors, numerous tumorigenic roles for OSM have been reported in a variety of cancers. In metabolic diseases, OSM signaling may be required for homeostasis in both the liver and the adipose tissue, since abrogation of OSM signaling causes obesity, hepatic steatosis, and insulin resistance. This review aims to: 1) examine the current literature regarding the role of OSM in the development of cancers and insulin resistance; and 2) propose a possible link between cancerassociated OSM and the development of the insulin resistance observed with cancer cachexia. Conclusion: In light of the potential links between cancer-associated OSM and cachexia-related insulin resistance, additional research is needed, especially given the possible link between these disease states. When considering OSM as a pharmaceutical target, its tumorigenic effects and role in tissue homeostasis must be carefully considered.

Background: Insulin resistance is a pathological condition characterized by the failure of target cells to uptake and metabolize glucose in response to insulin. In particular, the elevated concentrations of glucose, insulin and free insulin growth factor-1, which result from insulin resistance, may generate a pro-inflammatory and protumorigenic state. These alterations may underlie the increased risk to develop various types of cancer as well as the worse cancer prognosis observed in obese and diabetic patients. MicroRNAs are short molecules of noncoding endogenous RNA, which are involved in several physio-pathological conditions like glucose homeostasis, lipid metabolism, insulin signaling and resistance. MicroRNAs play also a crucial role in tumorigenesis, acting as oncomirs or tumor suppressors depending on the cell context. Methods: Here, we recapitulate the role of certain microRNAs that are associated with both insulin resistance and cancer, and discuss their potential to be considered as therapeutic targets. Results: Several studies have highlighted the action of diverse microRNAs in the aforementioned disorders. For instance, three microRNA clusters namely miR-103/107, miR-221/222 and miR-29 have been found to be upregulated in insulin resistance and certain types of cancer. These microRNAs have been shown to target genes like PTEN, Dicer and caveolins that are largely involved in important processes relevant to both insulin resistance and cancer. Conclusion: Certain microRNAs may represent potential drug targets common to both insulin resistance and cancer. In particular, the inhibition of miR-103/107, miR-221/222 and miR-29 may be taken into account in novel pharmacological approaches aiming to treat these two disorders.

Background: The tumor suppressor PTEN serves as a negative regulator of PI3K/PTEN/Akt signaling pathway that regulates cellular functions such as cell growth, differentiation, proliferation and migration. The PI3K/PTEN/Akt signaling cascades might also have effect on glucose uptake via translocation of GLUT-4. Insulin controls energy storage and the whole body glucose homeostasis. Its binding to insulin receptor on the surface of diverse cells allows glucose entry into cells, and activates a variety of cellular actions. Insulin resistance is a common metabolic feature and established risk factor of many diseases. Its fundamental principle is inability of insulin to exert its normal metabolic effects, and nutrient imbalance and abnormal lipid accumulation in skeletal muscle, liver and adipose tissues. Methods: We review the literature on the structure and function of PTEN and its involvement in insulin resistance and tumor regulation, and summarized the detailed scientific achievements on this topic. Results: Suppressing PTEN expression plays a role in pro- or anti-inflammatory state during insulin resistance associated with obesity. Selective disruption of PTEN in pancreatic α-cells demonstrates that a lack of PTEN reduces circulating glucagon levels and protects against hyperglycemia and insulin resistance in high-fat diet–fed mice. Loss-of-function PTEN mutations in adipose tissue results in systemic glucose tolerance and insulin sensitivity improvement because of ascended recruitment of the GLUT-4 towards the membrane. Targeting tissuespecific PTEN deletion improves insulin sensitivity and protects from systemic insulin resistance. PTEN, as an important tumor suppressor gene, is frequently deleted or mutated in a variety of human tumors. Inactivation of PTEN by loss-of-function mutations leads to deregulated hyperproliferation of cells, leading to oncogenic transformation. Conclusion: Considering PTEN's important role in insulin resistance and tumor regulation, targeting the PTEN gene and/or protein will likely provide an efficient strategy for therapeutic intervention in cancer and metabolic diseases like type 2 diabetes mellitus, obesity, and cardiovascular dysfunction.

Background: Peroxisome proliferator-activated receptor gamma (PPARγ) is a member of the nuclear receptor superfamily of ligand-inducible transcription factors that regulate adipogenesis, lipid metabolism, cell proliferation, inflammation and insulin sensitization. Abnormalities in PPARγ signaling have been associated with obesity, diabetes and cancer. The use of agonists to manage these diseases has been limited by their side effects. Accordingly, dual or pan agonists targeting the PPARα or PPARα and PPARδ, respectively, in addition to the PPARγ have been developed to overcome these side effects. This review details the shared PPARγ-dependent mechanisms between obesity-related cancers and diabetes and their potential therapeutic values. Method: We performed a systematic literature search through pubmed, Scopus and google scholar for articles on PPARγ-dependent signaling in diabetes or cancer. Results: There is growing co-occurrence of obesity-related cancers and diabetes, necessitating the use of effective therapies with the least amount of side effects for concurrent management of these diseases, by targeting potentially shared PPARγ-dependent mechanisms including abnormalities of the wnt/β-catenin, lysosomal acid lipase, inflammatory and cell cycle pathways, and the plasminogen activator system. Taking advantage of the multiple docking sites of the PPARγ and the pleiotropic nature of its signaling, structure-activity relationship and molecular docking studies have provided insights into designer PPARγ agonists or dual PPARα/γ agonists that modulate PPARγ signaling and negate side effects of full PPARγ agonists. Conclusion: Effective therapies, possibly devoid of side effects, for concurrent management of obesity-related cancers and diabetes can be developed through diligent structure-activity and molecular docking studies.

Background: Chemerin is an adipokine that induces insulin resistance by the mechanism of inflammation in adipose tissue but these are still unclear. A high level of chemerin in humans is considered as a marker of inflammation in insulin resistance and obesity as well as in type 2 diabetes mellitus. Despite the role of chemerin in insulin resistance progression, chemerin as one of the novel adipokines is proposed to be involved in high cancer risk and mortality. Aim: The aim of this paper was to review the role of CMKLR-1 receptor and the potential therapeutic target in the management of chemerin induced type 2 diabetes mellitus and cancer. Pathophysiology: Increased chemerin secretion activates an inflammatory response. The inflammatory response will increase the oxidative stress in adipose tissue and consequently results in an insulin-resistant state. The occurrence of inflammation, oxidative stress and insulin resistance leads to the progression of cancers. Conclusion: Chemerin is one of the markers that may involve in development of both cancer and insulin resistance. Chemokine like receptor- 1 (CMKLR-1) receptor that regulates chemerin levels exhibits a potential therapeutic target for insulin resistance, type 2 diabetes and cancer treatment.

Background: The intake of animal products in food has been associated with both the development of insulin resistance and gastrointestinal cancers (GIC). Through the digestion of animal protein and other constituents of animal products, the commensal bacteria in the gut (the gut microbiota) forms metabolites that can contribute to the development of both insulin resistance and cancer. Trimethylamine-N-Oxide (TMAO) is such a molecule and has recently drawn a lot of attention as it may be a risk factor for - and a link between - the gut microbiota and cardiovascular and renal disease. Further, TMAO is anticipated to have significance as a biomarker of - or even an independent risk factor for - other undesirable conditions, including insulin resistance and GIC. TMAO originates from a precursor, trimethylamine (TMA) that is a metabolite of various precursors; mainly choline and carnitine from ingested foods. Methods: We review the literature on TMAO as a shared risk factor and/or pathway between insulin resistance and GIC risk and take the reader through the literature of interventions that could reduce formation of TMAO and thereby the risk of insulin resistance and GIC. The purpose of the work is to generate a hypothesis to be tested in preclinical and clinical studies. Results: TMAO seems to be associated with both insulin resistance and GIC risk and also with atherosclerotic cardiovascular disease. One shared pathway is the formation of N-Nitroso compounds, a group of metabolites that can cause DNA-damage and epigenetic changes. Levels of TMAO can be reduced by limiting the dietary intake of certain foods, most importantly animal products. Further, certain drugs, namely Meldonium and 3,3-dimethyl- 1-butanol, may inhibit the formation of TMAO by inhibiting bacterial enzymes. Conclusions: The TMAO pathway and its metabolites are possibly involved in the development of two major health problems: insulin resistance and cancer. Within these pathways novel therapeutic targets may be identified. Further research is needed in order to verify existing or develop new pharmacological agents that modify these pathways and reduce the risk of insulin resistance and GIC.

Introduction: The influence of patient gender on the economic impact of health care has increasingly been examined in the recent literature. Gender appears to have an impact on healthcare resource consumption, due to possible differences in the patient’s response to a chosen therapeutic management strategy or to a healthcare intervention. Objective: The present work is aimed at collecting and reviewing evidences about the relationship between gender and economic consumption in health based on worldwide scientific literature published in the last 5 years. Method: We conducted a narrative review of evidence from an initial pool of 904 articles, selecting information about gender-specific economic impact in any therapeutic area. Results: After title, abstract and full text review, 111 articles were relevant to the paper scope. The reviewed studies seem to be confirming that a difference exists between males and females in the economic implications of healthcare management and that those differences are particularly relevant for cardiovascular and metabolic pathologies. Preliminary evidence suggests overall healthcare costs are slightly higher in females than males, while some specific and non-quantitative items of resource consumption, such as quality of prescriptions, might favour male patients. Results do not allow to clearly claiming an overall cost shift towards males or females, since their polarization varies depending on the considered cost item or event category. Conclusion: Studies suggested the presence of a gender difference in overall healthcare resource consumption and costs. Nevertheless, these aspects still lack thorough examination in literature and further analyses would be required on longer time periods.

The most dramatic feature of life on Earth is our adaptation to the cycle of day and night. Throughout evolutionary time, almost all living organisms developed a molecular clock linked to the light-dark cycles of the sun. In present time, we know that this molecular clock is crucial to maintain metabolic and physiological homeostasis. Indeed, a dysregulated molecular clockwork is a major contributing factor to many metabolic diseases. In fact, the time of onset of acute myocardial infarction exhibits a circadian periodicity and recent studies have found that the light regulated circadian rhythm protein Period 2 (PER2) elicits endogenous cardioprotection from ischemia. Manipulating the molecular clockwork may prove beneficial during myocardial ischemia in humans. MicroRNAs are small non-coding RNA molecules capable of silencing messenger RNA (mRNA) targets. MicroRNA dysregulation has been linked to cancer development, cardiovascular and neurological diseases, lipid metabolism, and impaired immunity. Therefore, microRNAs are gaining interest as putative novel disease biomarkers and therapeutic targets. To identify circadian microRNA-based cardioprotective pathways, a recent study evaluated transcriptional changes of PER2 dependent microRNAs during myocardial ischemia. Out of 352 most abundantly expressed microRNAs, miR-21 was amongst the top PER2 dependent microRNAs and was shown to mediate PER2 elicited cardioprotection. Further analysis suggested circadian entrainment via intense light therapy to be a potential strategy to enhance miR-21 activity in humans. In this review, we will focus on circadian microRNAs in the context of cardioprotection and will highlight new discoveries, which could lead to novel therapeutic concepts to treat myocardial ischemia.

Background: The failing heart is characterized by a depleted metabolic energy reserve and the upregulation of several molecular mechanisms leading to cardiac hypertrophy, inflammation, fibrosis, angiogenesis, and apoptosis. Dietary or non-dietary supplementation of vitamins could potentially benefit energy balance. Objective: The objective of the present study was to evaluate all available information on vitamins supplementation in patients with chronic HF for possible beneficial effect on metabolic, inotropic, chronotropic and hemodynamic indices. Method: We searched MEDLINE via Pubmed by using the following terms: “chronic heart failure” OR “cardiomyopathy” AND "vitamins", “vitamin A”, “B complex vitamins”, "vitamin C", "ascorbic acid", “vitamin D”, “retinol”, “vitamin E”, “thiamine“, “riboflavin”, “niacin”, “pyridoxine”, “cobalamin”, “folate”, “pantothenic acid”, “biotin”, “tocopherol” and combinations of them. Results: Data regarding supplementation of micronutrients in HF for most vitamins were sparse, and the inference about cardiovascular outcomes was obscured by the heterogeneity of studies, high inherent morbidity, and mortality of this group of high-risk patients, limited sample sizes in certain studies, unclear design and lack of head to head comparisons. Most vitamins in human trials failed to offer survival, or robust beneficial effect. Mostly indirect favorable evidence is derived from patients with deficiencies of certain micronutrients rather than their ad hoc supplementation. Conclusion: While vitamins and micronutrients are promising compounds for optimizing myocardial metabolism and homeostasis in HF, additional randomized clinical trials of larger scale are warranted to demonstrate the benefits of their supplementation in this high risk group of patients.

Background: Diabetes mellitus type 2 (T2DM) often co-exists with hypertension, and this aggregation of co-morbidities amplifies the risk for future cardiovascular events. Therefore, it appears crucial to understand the essence of choosing oral and non-insulin injectable anti-diabetic drugs (ADs) with a favorable hemodynamic impact that could partially attenuate the increased baseline cardiovascular risk. Objective: We sought to evaluate the effect of ADs on blood pressure (BP) indices and to assess the potential role of certain ADs towards hypertension treatment. Method: We performed a systematic review of the literature searching MEDLINE via Pubmed for all human studies implementing ADs, either individually or in combinations. Results: Metformin was found to reduce BP in small cohorts but failed to confirm its beneficial effect in a metaanalysis of 41 studies. Thiazolidinediones are associated with BP lowering but are contraindicated in patients with heart failure. Sulfonylureas, on the other hand, may increase BP, while a-glucosidase inhibitors, DPP-4 inhibitors, and SGLT2 inhibitors activate favorable pathophysiologic mechanisms serving as potential BP lowering agents. Relevant BP reduction was established for GLP-1 Ras in most clinical trials. Conclusion: The favorable hemodynamic impact of certain classes of ADs might provide synergistic or incremental therapeutic benefits in high-risk patients suffering from both T2DM and hypertension. Additional randomized trials designed under the hypothesis of the emerging beneficial hemodynamic effect of ADs are expected to provide more robust evidence and to guide the optimization of combined treatment strategies in this challenging group of patients.

Galanin-like peptide (GALP) is a neuropeptide involved in the regulation of food intake behavior, body weight and energy metabolism. In previous studies, we demonstrated that the intranasal administration of GALP has weight loss effects, although the mechanism of this action was not clarified. The aim of this study was to demonstrate the functional significance of GALP on lipid metabolism in the liver. Mice were fed a high fat diet to cause diet-induced obesity (DIO) and then administered GALP intranasally for 2 weeks (experimental), or vehicle (control). Body weights, along with lipid levels in the plasma and liver, and lipid metabolism-related gene expression in the liver were subsequently measured. Body weight gain was decreased by the GALP treatment compared to the control group. Lipid droplet levels in hepatocytes and hepatic triglyceride levels were decreased in the GALP group compared with the vehicle group, whereas hepatic fatty acid β-oxidation-related gene mRNA levels were increased in the GALP group. These results suggest that the intranasal administration of GALP has an inhibitory effect on lipid accumulation in the liver.