Role of Serum and Glucocorticoid-Inducible Kinase (SGK)-1 in Senescence: A Novel Molecular Target Against Age-Related Diseases

Senescence is a phenomenon characterized by a progressive decline of body homeostasis. Premature senescence acts when the cellular system is not able to adequately respond to noxious stimuli by synthesis of stressor molecules. Among those, serum-and-glucocorticoidinducible kinase-1 (SGK-1) dramatically increases under typical physiopathological conditions, such as glucocorticoid or mineralcorticoids exposure, inflammation, hyperglycemia, and ischemia. SGK-1 has been implicated in mechanism regulating oxidative stress, apoptosis, and DNA damage, which are all leading to a state of accelerating aging. Moreover, SGK-1-sensitive ion channels participate in the regulation of renal Na(+)/K(+) regulation, blood pressure, gastric acid secretion, cardiac action potential, and neuroexcitability. Recently, we demonstrated in endothelial cells as an increase in SGK-1 activity and expression reduces oxidative stress, improves cell survival and restores insulin-mediated nitric oxide production after hyperglycemia. Moreover, we showed as SGK-1 delays the onset of senescence by increasing telomerase activity, significantly decreasing reactive oxygen species (ROS) production, and by directly interacting with hTERT. Therefore, SGK-1 may represent a specific target to further develop novel therapeutic options against chronic diseases such as diabetes typical of aging. SGK-1 has been also associated with cancer, neurodegenerative diseases, and cardiovascular disease, among other age-related diseases. However, to date, the data available on SGK-1 and aging, are sparse, controversial, and only from C. elegans experimental models. In this review we sought to discuss the possible implication of SGK-1 in mechanisms regulating senescence and age-related diseases. Moreover, we aimed to discuss and identify the possible role of SGK-1 as possible molecular target to counteract and prevent aging.

Inhibition of hERG potassium channel by the antiarrhythmic agent mexiletine and its metabolite m-hydroxymexiletine

Mexiletine is a sodium channel blocker, primarily used in the treatment of ventricular arrhythmias. Moreover, recent studies have demonstrated its therapeutic value to treat myotonic syndromes and to relieve neuropathic pain. The present study aims at investigating the direct blockade of hERG potassium channel by mexiletine and its metabolite m-hydroxymexiletine (MHM). Our data show that mexiletine inhibits hERG in a time- and voltage-dependent manner, with an IC₅₀ of 3.7 ± 0.7 μmol/L. Analysis of the initial onset of current inhibition during a depolarizing test pulse indicates mexiletine binds preferentially to the open state of the hERG channel. Looking for a possible mexiletine alternative, we show that m-hydroxymexiletine (MHM), a minor mexiletine metabolite recently reported to be as active as the parent compound in an arrhythmia animal model, is a weaker hERG channel blocker, compared to mexiletine (IC₅₀ = 22.4 ± 1.2 μmol/L). The hERG aromatic residues located in the S6 helix (Tyr652 and Phe656) are crucial in the binding of mexiletine and the different affinities of mexiletine and MHM with hERG channel are interpreted by modeling their corresponding binding interactions through ab initio calculations. The simulations demonstrate that the introduction of a hydroxyl group on the meta-position of the aromatic portion of mexiletine weakens the interaction of the drug xylyloxy moiety with Tyr652. These results provide further insights into the molecular basis of drug/hERG interactions and, in agreement with previously reported results on clofilium and ibutilide analogs, support the possibility of reducing hERG potency and related toxicity by modifying the aromatic pattern of substitution of clinically relevant compounds.

Predictive value of HDL cholesterol for cancer-associated venous thromboembolism during chemotherapy

BACKGROUND

Dyslipidemia is a well-known risk factor for the development of atherothrombosis; however, its involvement in venous thromboembolism (VTE) is still debated. Low levels of HDL cholesterol (HDL-C) have been found to be associated with VTE, which is a common complication of cancer and its treatment. VTE incidence is increased in cancer patients, especially those undergoing chemotherapy.

OBJECTIVE

We sought to investigate the value of pretreatment HDL-C in the risk prediction of future VTE in a population of ambulatory cancer patients undergoing chemotherapy.

PATIENTS AND METHODS

Blood lipid composition was retrospectively evaluated in 592 consecutive patients with primary (n = 373) or relapsing/recurrent (n = 219) solid cancers at the start of a new chemotherapy regimen (12% neoadjuvant, 31% adjuvant, 57% metastatic).

RESULTS

VTE occurred during chemotherapy in 38 patients (median time-to-event: 3 months). Mean HDL-C levels were lower in patients who developed VTE during chemotherapy (41 mg dL(-1) ; standard deviation [SD] 13 mg dL(-1) ) than in those who did not (48 mg dL(-1) ; SD 14 mg dL(-1) ). Cox proportional hazard survival analysis showed that HDL-C levels ≤ 43 mg dL(-1) were able to significantly predict a first VTE episode, with a hazard ratio of 2.87 (95% confidence interval 1.45-5.68). Moreover, patients with HDL-C levels ≤ 43 mg dL(-1) had worse 1-year VTE-free survival (86%) than those with HDL-C levels > 43 mg dL(-1) (96%; log rank test, 3.14).

CONCLUSIONS

Patients with low HDL-C levels have a three-fold higher risk of developing a first VTE episode during chemotherapy. Baseline analysis of HDL-C levels might be of clinical value in predicting VTE in cancer outpatients treated with anticancer drugs.

A prospective observational study to evaluate G-CSF usage in patients with solid tumors receiving myelosuppressive chemotherapy in Italian clinical oncology practice

Febrile neutropenia (FN) is a severe dose-limiting side effect of myelosuppressive chemotherapy in patients with solid tumors. Clinical practice guidelines recommend primary prophylaxis with G-CSF in patients with an overall ≥ 20 % risk of FN. AIOM Italian guidelines recommend starting G-CSF within 24-72 h after chemotherapy; for daily G-CSF, administration should continue until the absolute neutrophil count (ANC) is 1 × 10(9)/L post-nadir and should not be terminated after ANC increase in the early days of administration. The aim of this study was to assess guideline adherence in oncology practice in Italy. In this multicenter, prospective, observational study, patients were enrolled at the first G-CSF use in any cycle and were followed for two subsequent cycles (or until the end of chemotherapy if less than two additional cycles). Primary objective was to explore G-CSF use in Italian clinical practice; therefore, data were collected on the G-CSF type, timing of administration, and number of doses. 512 eligible patients were enrolled (median age, 62). The most common tumor types were breast (36 %), lung (18 %), and colorectal (13 %). A total of 1,164 G-CSF cycles (daily G-CSF, 718; pegfilgrastim, 446) were observed. Daily G-CSF was administered later than 72 h after chemotherapy in 42 % of cycles, and the median [range] number of doses was four [1, 10]. Pegfilgrastim was administered later than 72 h in 8 % of cycles. G-CSF prophylaxis in Italy is frequently administered in a manner which is not supported by evidence-based guidelines. As this practice may lead to poor outcomes, educational initiatives are recommended.

TNF-α gene promoter polymorphisms and risk of venous thromboembolism in gastrointestinal cancer patients undergoing chemotherapy

BACKGROUND

TNF-α has been proposed as a predictive factor for venous thromboembolism (VTE). Genetic polymorphisms could regulate TNF-α production. However, the relationship between TNFA gene variants and VTE is not clarified. This study aims to investigate the predictive role of five different TNFA gene promoter SNPs, or their haplotype combination(s), for a first VTE episode in gastrointestinal cancer out-patients treated with chemotherapy.

PATIENTS AND METHODS

Serum TNF-α levels and TNFA -863C/A, -857C/T, -376G/A, -308G/A and -238G/A gene promoter polymorphisms were retrospectively evaluated in 314 subjects, including 157 controls and 157 Caucasian patients with histologically diagnosed GI cancers beginning chemotherapy delivery (5-fluorouracil either as monotherapy or in combination with platinum compounds or irinotecan).

RESULTS

Haplotype analysis showed that a five-loci haplotype (CTGGG haplotype) has higher frequency in GI cancer patients who developed VTE (n = 15) during chemotherapy [odds ratio = 2.7, 95% confidence interval (CI) 1.04-7.11, P = 0.04]. GI patients who remained VTE-free did not differ in CTGGG haplotype frequency from controls. No association was observed between serum TNF-α levels and TNFA haplotype, but both were independent predictors of VTE. Approximately 20% of GI cancer patients carrying the CTGGG haplotype developed VTE compared with 4% of the remaining 101 patients (hazard ratio = 5.6, 95% CI 1.8-17.6, P = 0.003).

CONCLUSION

These results suggest that TNFA might represent a candidate gene contributing to VTE pathogenesis in GI cancer patients and suggest that VTE risk during chemotherapy might be genetically identified. Validation studies are needed for translation into clinical practice.

Preoperative neuroimmunotherapy with subcutaneons low-dose interleukin-2 and melatonin in patients with gastrointestinal tumors - its efficacy in preventing surgery-induced lymphocytopenia

Our previous studies have shown that a preoperative injection of high dose IL-2 is able to abrogate surgery-induced immunosuppression in colorectal cancer patients. Moreover, our previous clinical investigations have indicated the possibility of amplifying IL-2 activity by a concomitant administration of the pineal immunomodulating hormone melatonin (MLT). On this basis, a biological study was performed to investigate the immune effects of a preoperative biotherapy consisting of low-dose IL-2 plus MLT in patients with gastrointestinal tumors. The study included 20 consecutive patients with gastrointestinal tract tumors, who underwent radical or palliative surgery. Patients were randomized to receive no preoperative treatment or a presurgical neuroimmunotherapeutic regimen consisting of low dose of IL-2 and MLT. IL-2 was injected subcutaneously at 3 million IU twice/day for 5 days in combination with MLT at 40 mg/day in the evening. Patients underwent surgery within 36 h from the last IL-2 injection. The mean number of lymphocytes, T lymphocytes and NK cells significantly decreased during the postoperative period in control patients, whereas it increased in patients pre-treated by immunotherapy. CD25-positive mean cell number increased in both groups of patients; however, postoperative mean number of CD25 expressing cells was significantly higher in patients pretreated with IL-2 and MLT than in controls. No immunotherapy-related toxicity occurred. This preliminary study would suggest that a neuroimmunotherapeutic regimen with low-dose IL-2 and MLT given preoperatively is a well tolerated therapy, which is able to prevent surgery-induced lymphocytopenia in cancer patients. This perioperative manipulation of host anticancer defenses could have a prognostic role in the clinical course of the neoplastic disease.

Obesity-driven inflammation and colorectal cancer

Visceral obesity is characterized by increased risk of cardiovascular disease as well as higher incidence of malignancies, including colorectal cancer (CRC), although the mechanisms linking excess adiposity with cancer are only partly characterized. Visceral obesity is currently acknowledged as a chronic inflammatory disorder and a growing body of evidence demonstrates the interconnections between obesity-related secretion pattern of adipo/cytokines and CRC. Specific molecules derived from the visceral adipose tissue (VAT), including adiponectin, leptin and resistin, are able to establish a positive feedback loop, thus increasing the proinflammatory and insulin resistant state and promoting tumorigenesis. Interestingly, these molecules have emerged as novel prognostic factors and therapeutic targets. This review will focus on current molecular and clinical evidence linking VAT-related inflammation to CRC initiation and progression, and summarize the role of dietary factors and lifestyle interventions aimed at promoting weight control and physical activity on CRC prevention and prognosis.

A probiotics-containing biscuit modulates the intestinal microbiota in the elderly

OBJECTIVES

Evaluation of the impact of a biscuit containing the probiotics Bifidobacterium longum Bar33 and Lactobacillus helveticus Bar13 on the intestinal microbiota in the elderly.

DESIGN

Randomized double-blind placebo-controlled trial.

PARTICIPANTS

Thirty-two elderly volunteers living in Italy. The group was composed of 19 women and 13 men aged between 71 and 88 years (mean 76).

INTERVENTION

Subjects were randomized in two groups consuming one dose of the probiotics-containing biscuit or placebo once a day for 30 days.

MEASUREMENTS

For each subject the intestinal microbiota was characterized using the phylogenetic microarray platform HTF-Microbi.Array before and after intervention.

RESULTS

Our data demonstrated that one-month consumption of a probiotics-containing biscuit was effective in redressing some of the age-related dysbioses of the intestinal microbiota. In particular, the probiotic treatment reverted the age-related increase of the opportunistic pathogens Clostridium cluster XI, Clostridium difficile, Clostridium perfringens, Enterococcus faecium and the enteropathogenic genus Campylobacter.

CONCLUSION

The present study opens the way to the development of elderly-tailored probiotic-based functional foods to counteract the age-related dysbioses of the intestinal microbiota.

Insulinemia and the risk of breast cancer and its relapse

A fairly large body of evidence has shown that insulin is a tumour-promoting agent, especially for breast cancer. High circulating and microenvironmental levels of insulin may directly increase the risk of breast cancer via the activation of cognate receptors expressed on normal and cancer cells and indirectly be associated with other known metabolic risk factors of cancer that usually are present in conjunction with the hyperinsulinic state. The focus of this review is to analyse and discuss available data in the literature on the possible causative/prognostic role of insulin resistance/hyperinsulinemia in breast cancer development and progression.

Phytochemical, antioxidant and anti-α-glucosidase activity evaluations of Bergenia cordifolia

The antioxidant, anti-α-glucosidase and anticholinesterase activity of the leaves and rhizomatous extract of Bergenia cordifolia were investigated. The rhizomes extract that showed a higher degree of 1,1-diphenyl-2-picrylhydrazyl radical scavenging and anti-α-glucosidase activity than reference compounds (rutin and acarbose respectively) were subjected to phytochemical analysis. The study revealed that previously unknown minor constituents from the plant, (+)-catechin 3-O-gallate, (+)-catechin 3,5-di-O-gallate and 1,2,4,6-tetra-O-galloyl-β-D-glucopyranoside, were the radical scavenging and anti-α-glucosidase principles. These compounds as well as the crude extracts were weak acetylcholienesterase inhibitors, suggesting a higher degree of selectivity against α-glucosidase enzyme. In comparison with the minor constituents, the previously known major constituents of the plant, bergenin and arbutin, were poor radical scavengers and enzyme inhibitors.