SGLT2 inhibitor ipragliflozin attenuates breast cancer cell proliferation.

Cancer is currently one of the major causes of death in patients with type 2 diabetes mellitus. We previously reported the beneficial effects of the glucagon-like peptide-1 receptor agonist exendin-4 against prostate and breast cancer. In the present study, we examined the anti-cancer effect of the sodium-glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin using a breast cancer model. In human breast cancer MCF-7 cells, SGLT2 expression was detected using both RT-PCR and immunohistochemistry. Ipragliflozin at 1-50 µM significantly and dose-dependently suppressed the growth of MCF-7 cells. BrdU assay also revealed that ipragliflozin attenuated the proliferation of MCF-7 cells in a dose-dependent manner. Because the effect of ipragliflozin against breast cancer cells was completely canceled by knocking down SGLT2, ipragliflozin could act via inhibiting SGLT2. We next measured membrane potential and whole-cell current using the patch clamp technique. When we treated MCF-7 cells with ipragliflozin or glucose-free medium, membrane hyperpolarization was observed. In addition, glucose-free medium and knockdown of SGLT2 by siRNA suppressed the glucose-induced whole-cell current of MCF-7 cells, suggesting that ipragliflozin inhibits sodium and glucose cotransport through SGLT2. Furthermore, JC-1 green fluorescence was significantly increased by ipragliflozin, suggesting the change of mitochondrial membrane potential. These findings suggest that the SGLT2 inhibitor ipragliflozin attenuates breast cancer cell proliferation via membrane hyperpolarization and mitochondrial membrane instability.

Efficacy and safety of sodium-glucose cotransporter 2 inhibitor ipragliflozin on glycemic control and cardiovascular parameters in Japanese patients with type 2 diabetes mellitus; Fukuoka Study of Ipragliflozin (FUSION).

Sodium-glucose co-transporter-2 inhibitors are newly established anti-diabetic agents with a unique glucose-lowering mechanism. In the present study, we investigated the efficacy and safety of the sodium-glucose co-transporter-2 inhibitor ipragliflozin (Ipra) for metabolic markers and cardiovascular parameters in Japanese patients with type 2 diabetes mellitus (T2DM). This study was an investigator-initiated, open-label, single-arm, multicenter prospective study. Patients with T2DM were treated with 50 mg Ipra for 24 and 52 weeks. The primary outcome investigated was the reduction of glycated hemoglobin (HbA1c) level. The secondary outcome was the change in other metabolic and cardiovascular parameters by 24 weeks. Before and after 52 weeks of treatment, carotid intima-media thickening (IMT) was measured by echography. A total of 134 patients were recruited in the study. A 24-week treatment with 50 mg Ipra daily significantly reduced HbA1c level (-0.6%, p < 0.01). Body mass index (BMI), blood pressure and serum C-peptide were reduced significantly (p < 0.05), while serum glucagon level was unchanged. Interestingly, the serum adiponectin and high-density lipoprotein (HDL) cholesterol levels were significantly increased by Ipra. However, 52 weeks of Ipra treatment did not change carotid IMT. Multiple regression analysis revealed that the only significant contributing factor for HbA1c reduction by Ipra was baseline HbA1c level. These data suggest that Ipra decreased not only glucose level but also BMI, blood pressure and serum C-peptide, and the contributing factor for HbA1c reduction by Ipra was baseline HbA1c level. Further, Ipra improved serum adiponectin and HDL cholesterol levels.

A Probable Case of Burn-out NASH Caused by Panhypopituitarism Secondary to Craniopharyngioma.

A 38-year-old man diagnosed with craniopharyngioma at 8 years old underwent repeated surgery and radiation therapy. Complications included panhypopituitarism including growth hormone deficiency and hypogonadism at 13 years old. At 26 years of age, a slight fatty liver was found, which finally developed into liver cirrhosis (LC) at 35 years old. Viral infection or other etiologies causing LC were negative on serum examinations. Liver biopsy suggested a possibility of burn-out non-alcoholic steatohepatitis. This case indicates that a long-standing growth hormone deficiency and hypogonadism may lead to LC as a type of burn-out non-alcoholic steatohepatitis.

Reduced vascular events in type 2 diabetes by biguanide relative to sulfonylurea: study in a Japanese Hospital Database.

BACKGROUND: Some oral hypoglycemic agents (OHAs) have been suggested to reduce the risk of cardiovascular disease (CVD) in type-2 diabetes mellitus (T2DM). We ascertained if OHAs affect CVD risk in a cohort analysis of a multicenter medical-cost accounting database in Japan. METHODS: Data of 4095 and 1273 T2DM patients in study 1 and study 2, respectively, were extracted from the database based on the following conditions: (i) began treatment with a single OHA (sulfonylurea, biguanide, thiazolidinedione, α-glucosidase inhibitor, glinide, or dipeptidyl peptidase-4 inhibitor) and continued the medication for ~1-1.4 years; (ii) hemoglobin (Hb)A1c level at baseline was available; (iii) age at baseline was 40-70 years; (iv) presence or absence of CVD history was not considered in study 1, but presence of CVD history was considered in study 2. Effects of OHAs relative to sulfonylurea on CVD risk according to ICD-10 were analysed using Kaplan-Meier curves during 104 weeks. RESULTS: In study 1 targeting T2DM patients with and without a history of CVD, initial and baseline treatment with a biguanide significantly lowered the risk of CVD compared with that with a sulfonylurea, and was independent of HbA1c control. In study 2, a similar significant preventive effect of a biguanide on CVD risk relative to a sulfonylurea was observed in T2DM patients with history of CVD. CONCLUSIONS: Initial treatment and baseline treatment with a biguanide can reduce CVD risk relative to a sulfonylurea independent of the blood glucose-lowering effect of the biguanide in Japanese T2DM patients.

Renoprotective Effects of DPP-4 Inhibitors.

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD) worldwide. Dipeptidyl peptidase (DPP)-4 inhibitors are widely used in the treatment of patients with type 2 diabetes (T2D). DPP-4 inhibitors reduce glucose levels by inhibiting degradation of incretins. DPP-4 is a ubiquitous protein with exopeptidase activity that exists in cell membrane-bound and soluble forms. It has been shown that an increased renal DPP-4 activity is associated with the development of DKD. A series of clinical and experimental studies showed that DPP-4 inhibitors have beneficial effects on DKD, independent of their glucose-lowering abilities, which are mediated by anti-fibrotic, anti-inflammatory, and anti-oxidative stress properties. In this review article, we highlight the current understanding of the clinical efficacy and the mechanisms underlying renoprotection by DPP-4 inhibitors under diabetic conditions.

Activation of overexpressed glucagon-like peptide-1 receptor attenuates prostate cancer growth by inhibiting cell cycle progression.

AIMS/INTRODUCTION: Incretin therapy is a common treatment for type 2 diabetes mellitus. We have previously reported an anti-prostate cancer effect of glucagon-like peptide-1 receptor (GLP-1R) agonist exendin-4. The attenuation of cell proliferation in the prostate cancer cell line was dependent on GLP-1R expression. Here, we examined the relationship between human prostate cancer severity and GLP-1R expression, as well as the effect of forced expression of GLP-1R using a lentiviral vector. MATERIALS AND METHODS: Prostate cancer tissues were extracted by prostatectomy and biopsy. GLP-1R was overexpressed in ALVA-41 cells using a lentiviral vector (ALVA-41-GLP-1R cells). GLP-1R expression was detected by immunohistochemistry and quantitative polymerase chain reaction. Cell proliferation was examined by growth curves and bromodeoxyuridine incorporation assays. Cell cycle distribution and regulators were examined by flow cytometry and western blotting. In vivo experiments were carried out using a xenografted model. RESULTS: GLP-1R expression levels were significantly inversely associated with the Gleason score of human prostate cancer tissues. Abundant GLP-1R expression and functions were confirmed in ALVA-41-GLP-1R cells. Exendin-4 significantly decreased ALVA-41-GLP-1R cell proliferation in a dose-dependent manner. DNA synthesis and G1-to-S phase transition were inhibited in ALVA-41-GLP-1R cells. SKP2 expression was decreased and p27Kip1 protein was subsequently increased in ALVA-41-GLP-1R cells treated with exendin-4. In vivo experiments carried out by implanting ALVA-41-GLP-1R cells showed that exendin-4 decreased prostate cancer growth by activation of GLP-1R overexpressed in ALVA41-GLP-1R cells. CONCLUSIONS: Forced expression of GLP-1R attenuates prostate cancer cell proliferation by inhibiting cell cycle progression in vitro and in vivo. Therefore, GLP-1R activation might be a potential therapy for prostate cancer.

Efficacy and safety of a combination of an insulin secretagogue and a dipeptidyl peptidase-4 inhibitor in Japanese patients with type 2 diabetes mellitus; the repaglinide glucose oscillation study in Fukuoka (REGO-F).

ABSTRACT: Dipeptidyl peptidase-4 inhibitors (DPP-4Is) are one of the most frequently prescribed anti-diabetic agents in Japan, and they are often used in combination with insulin secretagogues, such as sulfonylureas and glinides. In the present study, we determined the efficacy and safety of the use of repaglinide or glimepiride, a sulfonylurea, in combination with a DPP-4I, in Japanese patients with type 2 diabetes mellitus (T2DM). This study was an investigator-initiated, open-label, randomized, multi-center prospective study. Patients with T2DM, which was inadequately controlled using a DPP-4I, were randomized to a repaglinide group or a glimepiride group and treated for 48 weeks. The primary outcomes were the reductions in glycated hemoglobin (HbA1c) and glucose oscillation, identified using continuous glucose monitoring, after 12 weeks. The secondary outcome was the change in carotid intima-media thickness (IMT), measured by ultrasonography, after 48 weeks. A total of 61 patients were recruited and analyzed in the study. Twelve weeks of treatment with 1.5 mg repaglinide or 1 mg glimepiride significantly reduced HbA1c, and a larger reduction in HbA1c occurred in the repaglinide group than the glimepiride group. Mean subcutaneous glucose concentration was significantly reduced in both groups, but the glucose oscillation did not decrease. Interestingly, the mean left IMT significantly increased in the glimepiride group, but not in the repaglinide group. More hypoglycemic events were observed in the glimepiride group. These data suggest that repaglinide reduces HbA1c more effectively than glimepiride when used in combination with a DPP-4I, and causes fewer hypoglycemic events. TRAIL REGISTRY: This study is registered with UMIN-CTR (UMIN000018321).

Selective androgen receptor modulator, S42 has anabolic and anti-catabolic effects on cultured myotubes.

We previously identified a novel selective androgen receptor modulator, S42, that does not stimulate prostate growth but has a beneficial effect on lipid metabolism. S42 also increased muscle weight of the levator ani in orchiectomized Sprague-Dawley rats. These findings prompted us to investigate whether S42 has a direct effect on cultured C2C12 myotubes. S42 significantly lowered expression levels of the skeletal muscle ubiquitin ligase (muscle atrophy-related gene), atrogin1 and Muscle RING-Finger Protein 1(MuRF1) in C2C12 myotubes, as determined by real time PCR. Phosphorylation of p70 S6 kinase (p70S6K), an essential factor for promoting protein synthesis in skeletal muscle, was significantly increased by S42 to almost the same extent as by insulin, but this was significantly prevented by treatment with rapamycin, an inhibitor of mechanistic target of rapamycin complex 1 (mTORC1). However, phosphorylation of Akt, upstream regulator of mTORC1, was not changed by S42. S42 did not increase insulin-like growth factor 1 (Igf1) mRNA levels in C2C12 myotubes. These results suggest that S42 may have an anabolic effect through activation of mTORC1-p70S6K signaling, independent of IGF-1-Akt signaling and may exert an anti-catabolic effect through inhibition of the degradation pathway in cultured C2C12 myotubes.

Combined treatment with DPP-4 inhibitor linagliptin and SGLT2 inhibitor empagliflozin attenuates neointima formation after vascular injury in diabetic mice.

Incretin therapy has emerged as one of the most popular medications for type 2 diabetes. We have previously reported that the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin attenuates neointima formation after vascular injury in non-diabetic mice. In the present study, we examined whether combined treatment with linagliptin and the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin attenuates neointima formation in diabetic mice after vascular injury. Diabetic db/db mice were treated with 3 mg/kg/day linagliptin and/or 30 mg/kg/day empagliflozin from 5 to 10 weeks of age. Body weight was significantly decreased by empagliflozin and the combined treatment. Blood glucose levels and glucose tolerance test results were significantly improved by empagliflozin and the combined treatment, but not by linagliptin. An insulin tolerance test suggested that linagliptin and empagliflozin did not improve insulin sensitivity. In a model of guidewire-induced femoral artery injury in diabetic mice, neointima formation was significantly decreased in mice subjected to combined treatment. In an in vitro assay using rat aortic smooth muscle cells (RASMC), 100, 500, or 1000 nM empagliflozin significantly decreased the RASMC number in a dose-dependent manner. A further significant reduction in RASMC proliferation was observed after combined treatment with 10 nM linagliptin and 100 nM empagliflozin. These data suggest that combined treatment with the DPP-4 inhibitor linagliptin and SGLT2 inhibitor empagliflozin attenuates neointima formation after vascular injury in diabetic mice in vivo and smooth muscle cell proliferation in vitro.

High Prevalence of Diabetes in Patients With Primary Aldosteronism (PA) Associated With Subclinical Hypercortisolism and Prediabetes More Prevalent in Bilateral Than Unilateral PA: A Large, Multicenter Cohort Study in Japan.

OBJECTIVE: To investigate the prevalence and causes of diabetes in patients with primary aldosteronism (PA) in a multi-institutional cohort study in Japan. RESEARCH DESIGN AND METHODS: The prevalence of diabetes was determined in 2,210 patients with PA (diagnosed or glycated hemoglobin [HbA1c] ≥6.5% [≥48 mmol/mol]; NGSP) and compared with that of the Japanese general population according to age and sex. In 1,386 patients with PA and clear laterality (unilateral or bilateral), the effects of plasma aldosterone concentration (PAC), hypokalemia (<3.5 mEq/L), suspected subclinical hypercortisolism (SH; serum cortisol ≥1.8 µg/dL after 1-mg dexamethasone suppression test), and PA laterality on the prevalence of diabetes or prediabetes (5.7% ≤ HbA1c <6.5% [39 mmol/mol ≤ HbA1c <48 mmol/mol]) were examined. RESULTS: Of the 2,210 patients with PA, 477 (21.6%) had diabetes. This prevalence is higher than that in the general population (12.1%) or in 10-year cohorts aged 30-69 years. Logistic regression or χ2 test revealed a significant contribution of suspected SH to diabetes. Despite more active PA profiles (e.g., higher PAC and lower potassium concentrations) in unilateral than bilateral PA, BMI and HbA1c values were significantly higher in bilateral PA. PA laterality had no effect on the prevalence of diabetes; however, the prevalence of prediabetes was significantly higher in bilateral than unilateral PA. CONCLUSIONS: Individuals with PA have a high prevalence of diabetes, which is associated mainly with SH. The prevalence of prediabetes is greater for bilateral than unilateral PA, suggesting a unique metabolic cause of bilateral PA.

Prescription of oral hypoglycemic agents for patients with type 2 diabetes mellitus: A retrospective cohort study using a Japanese hospital database.

AIMS/INTRODUCTION: In treatment algorithms of type 2 diabetes mellitus in Western countries, biguanides are recommended as first-line agents. In Japan, various oral hypoglycemic agents (OHAs) are available, but prescription patterns are unclear. MATERIALS AND METHODS: Data of 7,108 and 2,655 type 2 diabetes mellitus patients in study 1 and study 2, respectively, were extracted from the Medical Data Vision database (2008-2013). Cardiovascular disease history was not considered in study 1, but was in study 2. Initial choice of OHA, adherence to its use, effect on glycated hemoglobin levels for 2 years and the second choice of OHA were investigated. RESULTS: In study 1, α-glucosidase inhibitor, glinide and thiazolidinedione were preferentially medicated in relatively lower glycated hemoglobin cases compared with other OHAs. The two most prevalent first prescriptions of OHAs were biguanides and dipeptidyl peptidase-4 inhibitors, and the greatest adherence was for α-glucosidase inhibitors. In patients treated continuously with a single OHA for 2 years, improvement in glycated hemoglobin levels was greatest for dipeptidyl peptidase-4 inhibitors. As a second OHA added to the first OHA during the first 2 years, dipeptidyl peptidase-4 inhibitors were chosen most often, especially if a biguanide was the first OHA. In study 2, targeting patients with a cardiovascular disease history, a similar tendency to study 1 was observed in the first choice of OHA, adherence and the second choice of OHA. CONCLUSIONS: Even in Japanese type 2 diabetes mellitus patients, a Western algorithm seems to be respected to some degree. The OHA choice does not seem to be affected by a cardiovascular disease history.

Combined Treatment with Exendin-4 and Metformin Attenuates Prostate Cancer Growth.

INTRODUCTION: Recently, the pleiotropic benefits of incretin-based therapy have been reported. We have previously reported that Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, attenuates prostate cancer growth. Metformin is known for its anti-cancer effect. Here, we examined the anti-cancer effect of Exendin-4 and metformin using a prostate cancer model. METHODS: Prostate cancer cells were treated with Exendin-4 and/or metformin. Cell proliferation was quantified by growth curves and 5-bromo-2'-deoxyuridine (BrdU) assay. TUNEL assay and AMP-activated protein kinase (AMPK) phosphorylation were examined in LNCaP cells. For in vivo experiments, LNCaP cells were transplanted subcutaneously into the flank region of athymic mice, which were then treated with Exendin-4 and/or metformin. TUNEL assay and immunohistochemistry were performed on tumors. RESULTS: Exendin-4 and metformin additively decreased the growth curve, but not the migration, of prostate cancer cells. The BrdU assay revealed that both Exendin-4 and metformin significantly decreased prostate cancer cell proliferation. Furthermore, metformin, but not Exendin-4, activated AMPK and induced apoptosis in LNCaP cells. The anti-proliferative effect of metformin was abolished by inhibition or knock down of AMPK. In vivo, Exendin-4 and metformin significantly decreased tumor size, and further significant tumor size reduction was observed after combined treatment. Immunohistochemistry on tumors revealed that the P504S and Ki67 expression decreased by Exendin-4 and/or metformin, and that metformin increased phospho-AMPK expression and the apoptotic cell number. CONCLUSION: These data suggest that Exendin-4 and metformin attenuated prostate cancer growth by inhibiting proliferation, and that metformin inhibited proliferation by inducing apoptosis. Combined treatment with Exendin-4 and metformin attenuated prostate cancer growth more than separate treatments.