Effect of gliclazide on DNA damage in human peripheral blood lymphocytes and insulinoma mouse cells

High throughput screen of small molecules as potential countermeasures to galactic cosmic radiation induced cellular dysfunction

Space travel increases galactic cosmic ray exposure to flight crews and this is significantly elevated once travel moves beyond low Earth orbit. This includes combinations of high energy protons and heavy ions such as ⁵⁶Fe or ¹⁶O. There are distinct differences in the biological response to low-energy transfer (x-rays) or high-energy transfer (High-LET). However, given the relatively low fluence rate of exposure during flight operations, it might be possible to manage these deleterious effects using small molecules currently available. Virtually all reports to date examining small molecule management of radiation exposure are based on low-LET challenges. To that end an FDA approved drug library (725 drugs) was used to perform a high throughput screen of cultured cells following exposure to galactic cosmic radiation. The H9c2 myoblasts, ES-D3 pluripotent cells, and Hy926 endothelial cell lines were exposed to a single exposure (75 cGy) using the 5-ion GCRsim protocol developed at the NASA Space Radiation Laboratory (NSRL). Following GCR exposure cells were maintained for up to two weeks. For each drug (@10µM), a hierarchical cumulative score was developed incorporating measures of mitochondrial and cellular function, oxidant stress and cell senescence. The top 160 scores were retested following a similar protocol using 1µM of each drug. Within the 160 drugs, 33 are considered to have an anti-inflammatory capacity, while others also indirectly suppressed pro-inflammatory pathways or had noted antioxidant capacity. Lead candidates came from different drug classes that included angiotensin converting enzyme inhibitors or AT1 antagonists, COX2 inhibitors, as well as drugs mediated by histamine receptors. Surprisingly, different classes of anti-diabetic medications were observed to be useful including sulfonylureas and metformin. Using a hierarchical decision structure, we have identified several lead candidates. That no one drug or even drug class was completely successful across all parameters tested suggests the complexity of managing the consequences of galactic cosmic radiation exposure.

The effects of glipizide on DNA damage and nuclear transport in differentiated 3T3-L1 adipocytes

BACKGROUND

Despite commonly use for treatment of type II diabetes, possible effects of glipizide on nuclear transport and DNA damage in cells are unknown. Since clinical response of glipizide may change with aging, the aim of the study was to investigate the effect of glipizide by comparing mature and senescent adipocytes.

METHODS AND RESULTS

The effects of glipizide were investigated in 3T3-L1 adipocytes. Effective and lethal doses were determined by real-time monitoring iCELLigence system. Comet assay was performed to determine DNA damage and quantitative PCR was conducted to detect gene expression levels. RAN expressions were found to be up regulated in mature 180 µM glipizide treated adipocytes compared to control group (p < 0.05); whereas down regulated in senescent 180 µM glipizide treated adipocytes compared to their control adipocytes (p < 0.05). Olive Tail Moment values were significantly higher in mature 180 µM glipizide treated adipocytes (MTG) and senescent 180 µM glipizide treated adipocytes (STG) comparing their untreated controls (p < 0.001 and p < 0.001 respectively). Also class 5 comets that shows severe DNA damage were found to be higher in both MTG and STG groups than their controls (p < 0.001 and p < 0.001, respectively). OTM values were higher in STG than MTG (p < 0.001).

CONCLUSIONS

This is the first study that reports glipizide caused DNA damage increasing with senescence in adipocytes. As a response to glipizide treatment Ran gene expression increased in mature; and decreased in senescent adipocytes. Further studies are needed to reveal the effect of glipizide on DNA and nuclear interactions in molecular level.

Alleviation of cisplatin-induced hepatotoxicity by gliclazide: Involvement of oxidative stress and caspase-3 activity

AIMS

Cisplatin (CP), as an effective alkylating agent, is widely used in cancer treatment, while hepatotoxicity is one of its side effects. Gliclazide (GLZ), as an oral hypoglycemic drug, has antioxidant and anti-inflammatory properties. This study was designed to investigate the protective effect of GLZ against CP-induced hepatotoxicity in mice.

METHODS

In this experimental study, 64 adult male mice randomly were allocated into eight groups (8 mice/group). Control, GLZ (5, 10, and 25 mg/kg, orally), CP (10 mg/kg, single dose, intraperitoneally), and CP+GLZ (in three doses). GLZ was administrated for 10 consecutive days. CP was injected on the 7th day of the study. At the end of the experiment, hepatotoxicity was evaluated by serum and tissue biochemical, histopathological, and immunohistochemical assessments.

RESULTS

The data were revealed that CP increased oxidative stress (increased MDA and reduced GSH), liver damage enzymes (ALT, AST, and ALP), and immunoreactivity of caspase-3 in liver tissue of CP-injected mice. Also, CP induced histopathological changes such as eosinophilic of hepatocytes, dilatation of sinusoids, congestion, and proliferation of Kupffer cells. GLZ administration significantly ameliorated serum functional enzyme and hepatic oxidative stress markers in CP-injected mice. In addition, the histological and immunohistochemical alterations were ameliorated in GLZ-treated mice. Of the three doses, 10 and 25 mg/kg were more effective.

CONCLUSIONS

In conclusion, GLZ with its antioxidant, anti-inflammatory, and anti-apoptotic activities, can be suggested as a promising drug in the treatment of CP-induced hepatotoxicity.

A potential role of calpains in sulfonylureas (SUs) -mediated death of human pancreatic cancer cells (1.2B4)

Sulfonylureas (SUs) are suggested to accelerate the pancreatic β-cells mass loss via apoptosis. However, little is known whether calpains mediate this process. The aim of the present study is to evaluate the involvement of calpains in SUs-induced death of human pancreatic cancer (PC) cell line 1.2B4. The cells were exposed to: glibenclamide, glimepiride and gliclazide for 72 h. The expression analysis of caspase-3 (CASP-3), TP53, calpain 1 (CAPN-1), calpain 2 (CAPN-2) and calpain 10 (CAPN-10) was detected using RT-PCR method. Intracellular Ca²⁺ concentrations, CASP-3 activity and total calpain activity were also evaluated. Our results have shown that glibenclamide and glimepiride decrease 1.2B4 cells viability with accompanied increase in intracellular Ca²⁺ concentration and increased expression of apoptosis-related CASP-3 and TP53. Gliclazide did not affect 1.2B4 cell viability and Ca²⁺ concentration, however, it downregulated CASP-3 and upregulated TP53. Interestingly, 50 μM glimepiride increased expression of CAPN-1, CAPN-2 and CAPN-10 whereas 50 μM glibenclamide solely upregulated CAPN-2 expression. We have shown that 10 μM and 50 μM glibenclamide and glimepiride increased the activity of CASP-3, but decreased total calpain activity. Our results suggest that calpains may be involved in glibenclamide- and glimepiride-induced death of PC cells. However, further investigation is required to confirm the engagement of calpains in SUs-mediated death of PC cells, especially studies on protein level of particular isoforms of calpains should be conducted.

Gliclazide attenuates cisplatin-induced nephrotoxicity through inhibiting NF-κB and caspase-3 activity

Cisplatin (CP), as a chemotherapeutic drug, causes nephrotoxicity that has limited the clinical utility of CP. Gliclazide (GLZ), as an antihyperglycemic drug, at low dose has antioxidant property. In this study, we aimed to investigate the protective effect of GLZ against CP-induced acute renal injury. Sixty-four BALB/c mice were randomly divided into eight groups. The groups were included as control, GLZ (5, 10, and 25 mg/kg), CP, and GLZ (5, 10, and 25 mg/kg) + CP. Renal function markers (serum creatinine and blood urea nitrogen), oxidative stress markers (malondialdehyde and glutathione), apoptotic marker (caspase-3), and NF-κB were histopathologically evaluated. The results of our study showed that increased urea and creatinine were evidence of CP-induced nephrotoxicity. Histopathological examination revealed tubular epithelial and Bowman degeneration, edema, and cytoplasmic vacuolation in renal tissue structure. Administration of GLZ reduced oxidative stress, caspase-3, and NF-κB activity, and improved kidney function markers in CP-treated mice compared with CP alone group. Also, we observed that the histological tissue structure of the kidney was maintained. GLZ at dose of 25 mg/kg had higher protective effect as compared with other doses. Overall, our study suggests that GLZ with antioxidant, antiapoptotic, and anti-inflammatory properties may be a promising new therapeutic agent to prevent CP-induced nephrotoxicity.

Incident Hepatocellular Carcinoma Risk in Patients Treated with a Sulfonylurea: A Nationwide, Nested, Case-Control Study

Several studies have shown that the use of sulfonylureas in patients with type 2 diabetes mellitus (T2DM) is associated with a higher risk of hepatocellular carcinoma (HCC). In this study, we investigated the effects of individual sulfonylureas on HCC development using the National Health Insurance Service-National Sample Cohort in South Korea. Among 47,738 subjects aged 40 years or older who had newly diagnosed with diabetes, 241 incident HCC cases and 1205 matched controls were identified. Adjusted odds ratios (ORs) as estimates of the relative risk of HCC were calculated using logistic regression analysis. Compared to patients never treated with a sulfonylurea, those treated with a sulfonylurea had a 1.7-fold increased risk of HCC development. Of the different types of sulfonylureas, the exclusive use of glimepiride was associated with a significantly elevated risk of HCC (OR = 1.89, 95% CI = 1.02-3.47) compared to those who were never treated with sulfonylureas. No significant associations were observed between exclusive gliclazide use and incident HCC (OR = 2.04, 95% CI = 0.75-5.52). In conclusion, the association between the use of sulfonylureas and risk of HCC was different according to the type of sulfonylurea, in patients with new-onset T2DM. Further prospective studies are warranted to confirm these results and translate them into clinical practice.

Gliclazide

Gliclazide is a second-generation oral hypoglycemic drug used for the treatment of noninsulin-dependent diabetes mellitus. It belongs to the sulfonylurea class that stimulates insulin secretion from pancreatic β-cells by inhibiting ATP-dependent potassium channels. Gliclazide also possesses unique antioxidant properties and other beneficial hemobiological effects. This profile represents a comprehensive description of the physical properties, chemical synthesis, spectroscopic characterization (FTIR, ¹H NMR, ¹³C NMR, UV, and single-crystal X-ray), methods of analysis, pharmacological actions, and pharmacokinetic and pharmacodynamic properties of the title drug.

The Use of Glyburide Compared With Other Sulfonylureas and the Risk of Cancer in Patients With Type 2 Diabetes

OBJECTIVE

To determine whether the use of glyburide is associated with an increased risk of cancer compared with the use of other second-generation sulfonylureas among patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The U.K. Clinical Practice Research Datalink was used to conduct a cohort study among 52,600 patients newly prescribed glyburide or other second-generation sulfonylureas between 1 January 1988 and 31 July 2013. A time-dependent Cox proportional hazards model was used to estimate adjusted hazard ratios (HRs) and 95% CIs of any cancer associated with the use of glyburide compared with the use of second-generation sulfonylureas. Secondary analyses were conducted to determine whether the association varied with cumulative duration of use and cumulative dose (expressed as defined daily dose [DDD]).

RESULTS

During 280,288 person-years of follow-up, 4,105 patients were given a new diagnosis of cancer (incidence rate 14.6 per 1,000 person-years). Overall, when compared with the use of other second-generation sulfonylureas, the use of glyburide was associated with a nonsignificant increased risk of any cancer (HR 1.09 [95% CI 0.98-1.22]). In secondary analyses, duration- and dose-response relationships were observed, with longer cumulative durations and cumulative doses associated with an increased risk of any cancer (>36 months: HR 1.21 [95% CI: 1.03-1.42]; >1,096 DDDs: HR 1.27 [95% CI 1.06-1.51]).

CONCLUSIONS

In this population-based cohort study, longer cumulative durations and higher cumulative doses of glyburide were associated with an increased risk of cancer.

Diabetes and cancer relationships

Diabetes and cancer are both heterogeneous and multifactorial diseases with tremendous impact on health worldwide. Epidemiologic evidence suggests that certain malignancies may be associated with diabetes, as well as with diabetes risk factors and, perhaps, with certain diabetes treatments. Numerous biological mechanisms could account for these relationships. Insulin-like growth factor (IGF)-1, IGF-2, IGF-1 receptors, insulin, and the insulin receptor play roles in the development and progression of cancers. Although evidence from randomized controlled trials does not support or refute associations of diabetes and its treatments with either increased or reduced risk of cancer incidence or prognosis, consideration of malignancy incidence rates and the magnitude of the trials that would be required to address these issues explains why such studies may not be readily undertaken.

Effects of sulfonylureas on tumor growth: a review of the literature

Type 2 diabetes mellitus patients are at higher cancer risk, probably because of hyperinsulinemia and insulin growth factor 1 pathway activation. The effects of antidiabetic drugs on cancer risk have been described and discussed in several studies suggesting opposite effects of the biguanide metformin and sulfonylureas on cancer incidence and mortality. The anticancer mechanisms of metformin have been clarified, and some clinical studies, particularly in breast cancer patients, have been published or are currently ongoing; however, data about the effects of sulfonylureas on cancer growth are less consistent. The aims of this work are to review preclinical evidence of second-generation sulfonylureas effects on tumor growth, to clarify the potential mechanisms of action, and to identify possible metabolic targets for patient selection. Most evidence is on the adenosine triphosphate-sensitive potassium channels inhibitor glibenclamide, which interacts with reactive oxygen species production thus inducing cancer cell death. Among diarylsulfonylureas, next-generation DW2282 derivatives are particularly promising because of the proapoptotic activity in multidrug-resistant cells.

Metformin and sulfonylureas in relation to cancer risk in type II diabetes patients: a meta-analysis using primary data of published studies

INTRODUCTION

Accumulating evidence suggests that patients with type 2 diabetes mellitus (T2DM) and hyperinsulinemia are at increased risk for developing malignancies. It remains to be fully elucidated whether use of metformin, an insulin sensitizer, and/or sulfonylureas, insulin secretagogues, affect cancer incidence in subjects with T2DM.

MATERIAL & METHODS

We performed a meta-analysis using PubMed, of randomized control trials (RCTs), cohorts, and case-control studies published through July 2012 that assess effects of metformin and/or sulfonylurea sulfonylureas on cancer risk at any site, in subjects with T2DM. Fixed and random effects meta-analysis models were used, and the effect size was summarized as relative risk (RR) for RCTs/cohorts and as odds ratio (OR) for the case-control studies.

RESULTS

Analysis of 24 metformin studies in subjects with T2DM showed that metformin use is associated with reduced risk for the development of cancer, in both cohort (RR=0.70 [95% CI=0.67-0.73]) and case-control studies (OR=0.90 [95% CI=0.84-0.98]), but this finding was not supported by RCTs (RR=1.01[95% CI=0.81-1.26]). Data from 18 sulfonylurea studies in subjects with T2DM showed that sulfonylurea use is associated with an increase in all-cancer risk, in cohort studies (RR=1.55 [95% CI=1.48 -1.63]), though data from RCTs (RR=1.17 [95% CI=0.95-1.45]) and case-control studies (OR=1.02 [95% CI=0.93-1.13]) failed to demonstrate a statistically significant effect.

CONCLUSIONS

This analysis using pooled primary data demonstrates that metformin use reduces, while sulfonylurea use may be associated with an increased cancer risk in subjects with T2DM. These findings need to be confirmed in large-scale RCTs before they are translated into clinical practice.

Use of sulphonylurea and cancer in type 2 diabetes-The Hong Kong Diabetes Registry

BACKGROUND

Hyperglycaemia is a risk factor for cancer and some sulphonylureas have anti-oxidant properties. This study examined associations between use of sulphonylureas and cancer.

METHODS

A consecutive cohort of 6103 Hong Kong Chinese patients with T2DM, free of cancer, was analysed using Cox models. Sulphonylurea usage was defined as use of the drugs at or within 2.5 years before enrolment and/or during follow-up periods. We adjusted for identified risk factors of cancer, use of other drugs, non-linear associations of lipids with cancer and probabilities of use of these drugs at different times and doses where appropriate.

RESULTS

During a median of 4.91 years of follow-up, 271 developed cancer. Glibenclamide, gliclazide and glipizide were ever used in 32.5% (n = 1983), 47.8% (n = 2920) and 13.5% (n = 823). After adjustment for covariates, use of gliclazide and glibenclamide was associated with reduced cancer risk in a dose-dependent manner. In addition, there were interactions between metformin and glibenclamide/glipizide use towards lower adjusted cancer risks.

CONCLUSIONS

In T2DM, use of glibenclamide and gliclazide may be associated with reduced cancer risk.

Sulphonylureas and cancer: a case-control study

This study was aimed at the assessment of incidence of malignancies in type 2 diabetic patients treated with different sulphonylureas. A matched case-control study was performed. Cases were 195 diabetic patients aged 69.0 +/- 9.2 years who had an incident malignancy. Controls were 195 diabetic patients, unaffected by cancer, who were matched with the corresponding case for age, sex, duration of diabetes, BMI, HbA1(c), comorbidity, smoking and alcohol abuse. Exposure to hypoglycaemic drugs during the 10 years preceding the event (or matching index date) was assessed. After adjusting for concomitant therapies, exposure to metformin and gliclazide for more than 36 months was associated with a significant reduction in the risk of cancer (adj. ORs with 95% CI: 0.28 (0.13-0.57), p < 0.001, and 0.40 (0.21-0.57), p = 0.004, respectively). Conversely, use of glibenclamide for at least 36 months was associated with increased incidence of malignancies (adj. OR 2.62 (1.26-5.42); p = 0.009). Treatment with insulin, thiazolidinediones, or acarbose, was not associated with significant differences in the incidence of cancer. Long-term treatments with individual sulphonylureas could have differential effects on the risk of cancer. In particular, the possible protective effect of gliclazide, as well as the risk associated with glibenclamide, deserves further investigation.

In vitro effect of gliclazide on DNA damage and repair in patients with type 2 diabetes mellitus (T2DM)

Type 2 diabetes mellitus is associated with elevated level of oxidative stress, which is one of the most important factors responsible for the development of chronic complications of this disease. Moreover, it was shown that diabetic patients had increased level of oxidative DNA damage and decreased effectiveness of DNA repair. These changes may be associated with increased risk of cancer in T2DM patients, since DNA damage and DNA repair play a pivotal role in malignant transformation. It was found that gliclazide, an oral hypoglycemic drug with antioxidant properties, diminished DNA damage induced by free radicals. Therefore, the aim of the present study was to evaluate the in vitro impact of gliclazide on: (i) endogenous basal and oxidative DNA damage, (ii) DNA damage induced by hydrogen peroxide and (iii) the efficacy of DNA repair of such damage. DNA damage and DNA repair in peripheral blood lymphocytes of 30 T2DM patients and 30 non-diabetic individuals were evaluated by alkaline single cell electrophoresis (comet) assay. The extent of oxidative DNA damage was assessed by DNA repair enzymes: endonuclease III and formamidopyrimidine-DNA glycosylase. The endogenous basal and oxidative DNA damages were higher in lymphocytes of T2DM patients compared to non-diabetic subjects and gliclazide decreased the level of such damage. The drug significantly decreased the level of DNA damage induced by hydrogen peroxide in both groups. Gliclazide increased the effectiveness of DNA repair in lymphocytes of T2DM patients (93.4% (with gliclazide) vs 79.9% (without gliclazide); P< or =0.001) and non-diabetic subjects (95.1% (with gliclazide) vs 90.5% (without gliclazide); P< or =0.001). These results suggest that gliclazide may protect against the oxidative stress-related chronic diabetes complications, including cancer, by decreasing the level of DNA damage induced by reactive oxygen species.

A combination of soy isoflavone supplementation and exercise improves lipid profiles and protects antioxidant defense-systems against exercise-induced oxidative stress in ovariectomized rats

Menopause is often accompanied with weight gain, metabolic lipid abnormalities, and oxidative stress. In this study, we investigated the combined effects of exercise and soy isoflavone supplementation on the lipid profiles and antioxidant capacities of ovariectomized rats. Twenty-five female Sprague-Dawley rats were divided into 5 groups: sham-operated, ovariectomized (OVX), OVX with exercise (OVX+EX), OVX with soy isoflavone supplementation (OVX+ISO), and OVX with both soy isoflavones and exercise (OVX+ISO+EX). After 12 weeks of intervention, antioxidant status was evaluated in collected blood samples by the ferric reducing ability of plasma (FRAP), glutathione (GSH) content, and sodium oxide dismutase (SOD) activity. DNA damage in the lymphocytes was determined using alkaline single-cell gel electrophoresis (the Comet assay). Although there were no significant differences in weight gain and food intake, weight gain was lower in OVX+EX, OVX+ISO, and OVX+ISO+EX than in OVX. OVX+EX, OVX+ISO, and OVX+ ISO+EX showed a significant decrease in total cholesterol, triglycerides, and LDL-cholesterol compared to OVX. The soy isoflavone supplemented group had significantly increased FRAP values and GSH contents in contrast to no changes in the exercised group, whereas exercise markedly increased SOD activity and H2O2-induced DNA tail length and tail moment. Exercise with soy isoflavone supplementation significantly increased FRAP values and had no difference on SOD activity, including DNA damage. These results demonstrate that a combined treatment of moderate exercise and soy isoflavone supplementation could exert a beneficial effect on weight control and lipid profiles, and offer protection from exercise-induced oxidative stress in postmenopausal women.