A SGLT2 inhibitor dapagliflozin suppresses prolonged ventricular-repolarization through augmentation of mitochondrial function in insulin-resistant metabolic syndrome rats

Abstract Background Metabolic syndrome (MetS) is a prevalent risk factor for cardiac dysfunction. Although SGLT2-inhibitors have important cardioprotective effects in hyperglycemia, their underlying mechanisms are complex and not completely understood. Therefore, we examined mechanisms of a SGLT2-inhibitor dapagliflozin (DAPA)-related cardioprotection in overweight insulin-resistant MetS-rats comparison with insulin (INSU), behind its glucose-lowering effect. Methods A 28-week high-carbohydrate diet-induced MetS-rats received DAPA (5 mg/kg), INSU (0.15 mg/kg) or vehicle for 2 weeks. To validate MetS-induction, we monitored all animals weekly by measuring body weight, blood glucose and HOMO-IR index, electrocardiograms, heart rate, systolic and diastolic pressures. Results DAPA-treatment of MetS-rats significantly augmented the increased blood pressure, prolonged Q–R interval, and low heart rate with depressed left ventricular function and relaxation of the aorta. Prolonged-action potentials were preserved with DAPA-treatment, more prominently than INSU-treatment, at most, through the augmentation in depressed voltage-gated K+-channel currents. DAPA, more prominently than INSU-treatment, preserved the depolarized mitochondrial membrane potential, and altered mitochondrial protein levels such as Mfn-1, Mfn-2, and Fis-1 as well as provided significant augmentation in cytosolic Ca2+-homeostasis. Furthermore, DAPA also induced significant augmentation in voltage-gated Na+-currents and intracellular pH, and the cellular levels of increased oxidative stress, protein-thiol oxidation and ADP/ATP ratio in cardiomyocytes from MetS rats. Moreover, DAPA-treatment normalized the increases in the mRNA level of SGLT2 in MetS-rat heart. Conclusions Overall, our data provided a new insight into DAPA-associated cardioprotection in MetS rats, including suppression of prolonged ventricular-repolarization through augmentation of mitochondrial function and oxidative stress followed by improvement of fusion–fission proteins, out of its glucose-lowering effect

Regulation of the unfolded protein response through ATF4 and FAM129A in prostate cancer

Cancer cells exploit many of the cellular adaptive responses to support their survival needs. One such critical pathway in eukaryotic cells is the unfolded protein response (UPR) that is important in normal physiology as well as disease states, including cancer. Since UPR can serve as a lever between survival and death, regulated control of its activity is critical for tumor formation and growth although the underlying mechanisms are poorly understood. Here we show that one of the main transcriptional effectors of UPR, activating transcription factor 4 (ATF4), is essential for prostate cancer (PCa) growth and survival. Using systemic unbiased gene expression and proteomic analyses, we identified a novel direct ATF4 target gene, family with sequence similarity 129 member A (FAM129A), which is critical in mediating ATF4 effects on prostate tumorigenesis. Interestingly, FAM129A regulated both PERK and eIF2α in a feedback loop that differentially channeled the UPR output. ATF4 and FAM129A protein expression is increased in patient PCa samples compared with benign prostate. Importantly, in vivo therapeutic silencing of ATF4-FAM129A axis profoundly inhibited tumor growth in a preclinical PCa model. These data support that one of the canonical UPR branches, through ATF4 and its target gene FAM129A, is required for PCa growth and thus may serve as a novel therapeutic target

Atezolizumab combined with chemotherapy in the first-line treatment of extensive-stage small cell lung cancer: a real-life data of the Turkish Oncology Group

Purpose Atezolizumab has been shown to be effective and safe in randomized trial in the first-line treatment of extensive-stage small cell lung cancer (SCLC). However, there are limited real-life data on atezolizumab. In this study, we aimed to determine the real-life efficacy and safety of atezolizumab combined with chemotherapy in the first-line treatment of extensive-stage SCLC. Methods This trial is a retrospective multicenter study of the Turkish Oncology Group, which included extensive-stage SCLC patients who received atezolizumab combined with chemotherapy in a first-line treatment. The characteristics of the patients, treatment and response rates, and PFS and OS are presented. Factors associated with PFS and OS were analyzed by univariate and multivariate analysis. Results A total of 213 patients at the 30 oncology centers were included. The median number of chemotherapy cycle was 5 (1-8) and atezolizumab cycle was 7 (1-32). After median 11.9 months of follow-up, median PFS and OS was 6.8 months (95%CI 5.7-7.8), and 11.9 months (95%CI 11-12.7), respectively. The ORR was 61.9%. ECOG-PS (p = 0.002) and number of metastatic sites (p = 0.001) were associated with PFS and pack-year of smoking (p = 0.05), while ECOG-PS (p = 0.03) and number of metastatic sites (p = 0.001) were associated with OS. Hematological side effects were common and toxicities were manageable. Conclusion This real-life data confirm the efficacy and safety of atezolizumab in combination with chemotherapy in first-line treatment of extensive-stage SCLC