Colorectal cancer remains a main cause of deaths worldwide, and novel agents are being searched to treat this disease. Polyphenols have emerged as promising therapeutic tools in cancer. Resveratrol (3,5,4′-trihydoxy-trans-stilbene) induces cell death in different tumor cell lines, and it also stimulates the proliferation of specific breast and prostate cancer cell lines. Here, we studied the impact of resveratrol over a 100-fold concentration range on cell death and proliferation of HT-29 colorectal adenocarcinoma cells. After 96 h of treatment, a biphasic pattern was observed. At lower concentrations (1 and 10 μmol/l), resveratrol increased the cell number, as did the polyphenol quercetin. At 50 or 100 μmol/l, resveratrol reduced the cell number and increased the percentage of apoptotic or necrotic cells, thus indicating cytotoxicity. On HCT116 colon cancer cells, however, no proliferative properties of resveratrol were observed. Resveratrol-induced cytotoxicity on HT-29 cells was associated with NADPH oxidase activation and increased levels of histone γH2AX, a marker of DNA damage, paralleled by enhanced sirtuin 6 levels, likely as a repair mechanism. Overall, resveratrol may be an effective tool in anti-tumor chemotherapy. However, since under some conditions it may favor tumor cell growth, appropriate local concentrations must be achieved to minimize unwanted effects of resveratrol.

Background: Abnormal accumulation of senescent cells in the vessel wall leads to a compromised vascular function contributing to vascular aging. Soluble DPP4 (dipeptidyl peptidase 4; sDPP4) secretion from visceral adipose tissue is enhanced in obesity, now considered a progeric condition. sDPP4 triggers vascular deleterious effects, albeit its contribution to vascular aging is unknown. We aimed to explore sDPP4 involvement in vascular aging, unraveling the molecular pathway by which sDPP4 acts on the endothelium. Methods: Human endothelial cell senescence was assessed by senescence-associated β-galactosidase assay, visualization of DNA damage, and expression of prosenescent markers, whereas vascular function was evaluated by myography over human dissected microvessels. In visceral adipose tissue biopsies from a cohort of obese patients, we explored several age-related parameters in vitro and ex vivo. Results: By a common mechanism, sDPP4 triggers endothelial cell senescence and endothelial dysfunction in isolated human resistance arteries. sDPP4 activates the metabotropic receptor PAR2 (protease-activated receptor 2), COX-2 (cyclooxygenase 2) activity, and the production of TXA ₂ (thromboxane A ₂ ) acting over TP (thromboxane receptor) receptors (PAR2–COX-2–TP axis), leading to NLRP3 (nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing 3) inflammasome activation. Obese patients exhibited impaired microarterial functionality in comparison to control nonobese counterparts. Importantly, endothelial dysfunction in obese patients positively correlated with greater expression of DPP4, prosenescent, and proinflammatory markers in visceral adipose tissue nearby the resistance arteries. Moreover, when DPP4 activity or sDPP4-induced prosenescent mechanism was blocked, endothelial dysfunction was restored back to levels of healthy subjects. Conclusions: These results reveal sDPP4 as a relevant mediator in early vascular aging and highlight its capacity activating main proinflammatory mediators in the endothelium that might be pharmacologically tackled.

Background and aims: Targeting inflammation is nowadays considered as a challenging pharmacological strategy to prevent or delay the development of vascular diseases. Angiotensin-(1-7) is a member of the renin-angiotensin system (RAS) that binds Mas receptors and has gained growing attention in the last years as a regulator of vascular homeostasis. Here, we explored the capacity of Ang-(1-7) to counteract human aortic smooth muscle cell (HASMC) inflammation triggered by RAS-dependent and –independent stimuli, such as Ang II or interleukin (IL)-1. Methods and Results: In cultured HASMC, the expression of iNOS and the release of nitric oxide were stimulated by both Ang II and IL-1, as determined by Western blot and indirect immunofluorescence or the Griess method, respectively. iNOS induction was inhibited by Ang-(1-7) in a concentration-dependent manner. This effect was equally blocked by two different Mas receptor antagonists, A779 and D-Pro7-Ang-(1-7), suggesting the participation of a unique Mas receptor subtype. Using pharmacological inhibitors, the induction of iNOS was proven to rely on the consecutive upstream activation of NADPH oxidase and NF-B. Indeed, Ang-(1-7) markedly inhibited the activation of the NADPH oxidase and subsequently of NF-B, as determined by lucigenin-derived chemiluminiscence and electromobility shift assay, respectively. Conclusion: Ang-(1-7) can act as a counter-regulator of the inflammation of vascular smooth muscle cells triggered by Ang II, but also by other stimuli beyond the RAS. Activating or mimicking the Ang-(1-7)/Mas axis may represent a pharmacological opportunity to attenuate the pro-inflammatory environment that promotes and sustains the development of vascular diseases.

A highly complex network of organ communication plays a key role in regulating metabolic homeostasis, specifically due to the modulation of the insulin signaling machinery. As a paradigm, the role of adipose tissue in organ crosstalk has been extensively investigated, but tissues such as muscles and the liver are equally important players in this scenario. Perturbation of organ crosstalk is a hallmark of insulin resistance, emphasizing the importance of crosstalk molecules in the modulation of insulin signaling, potentially leading to defects in insulin action. Classically secreted proteins are major crosstalk molecules and are able to affect insulin signaling in both directions. In this review, we aim to focus on some crosstalk mediators with an impact on the early steps of insulin signaling. In addition, we also summarize the current knowledge on the role of extracellular vesicles in relation to insulin signaling, a more recently discovered additional component of organ crosstalk. Finally, an attempt will be made to identify inter-connections between these two pathways of organ crosstalk and the potential impact on the insulin signaling network.

Aim: To determine if a novel positive allosteric modulator of the γ‐aminobutyric acid type A (GABA _A ) receptor, the thioacrylamide‐derivative HK4, which does not penetrate the blood–brain barrier, protects human hepatocytes against lipotoxicity‐induced injury. Materials and Methods: Allosteric modulation of the GABA _A receptor by HK4 was determined by patch clamp in HEK‐293 cells, calcium influx in INS‐1E cells and by using the specific GABA _A channel blockers picrotoxin and tert‐butylbicyclophosphorothionate (TBPS) in HepG2 cells. Apoptosis was analysed using caspase 3/7, terminal deoxynucleotidyl transferase‐dUTP nick end labelling (TUNEL) and array assays in HepG2 cells and/or human primary hepatocytes. Phosphorylation of STAT3 and the NF‐κB subunit p65, protein disulphide isomerase (PDI) and poly‐ADP‐ribose polymerase‐1 (PARP‐1) was detected by Western blotting. Results: Patch clamping, calcium influx measurements and apoptosis assays with the non‐competitive GABA _A channel blockers picrotoxin and TBPS proved HK4 as a selective positive allosteric modulator of the GABA _A receptor. In HepG2 cells, which expressed the main GABA _A receptor subunits, HK4 prevented palmitate‐induced apoptosis. This protective effect was mediated by downregulation of caspase 3/7 activity and was additionally verified by TUNEL assay. HK4 effectively prevented palmitate‐induced apoptosis in human primary hepatocytes. HK4 reduced STAT3 and NF‐κB phosphorylation, reduced cleaved PARP‐1 expression and upregulated the endoplasmic reticulum (ER) chaperone PDI. Conclusions: HK4 reduced lipotoxic‐induced apoptosis by preventing inflammation, DNA damage and ER stress. We propose that the effect of HK4 is mediated by STAT3 and NF‐κB. It is suggested that thioacrylamide compounds represent an innovative pharmacological tool to treat or prevent non‐alcoholic steatohepatitis as first‐in‐class drugs.