Therapeutic Effect of Proteinase-Activated Receptor-1 Antagonist on Colitis-Associated Carcinogenesis.

BACKGROUND & AIMS: Inflammatory bowel disease is associated with carcinogenesis, which limits the prognosis of the patients. The local expression of proteinases and proteinase-activated receptor 1 (PAR1) increases in inflammatory bowel disease. The present study investigated the therapeutic effects of PAR1 antagonism on colitis-associated carcinogenesis. METHODS: A colitis-associated carcinogenesis model was prepared in mice by treatment with azoxymethane (AOM) and dextran sulfate sodium (DSS). PAR1 antagonist E5555 was administered in long- and short-term protocol, starting on the day of AOM injection and 1 week after completing AOM/DSS treatment, respectively. The fecal samples were collected for metagenome analysis of gut microbiota. The intestinal myofibroblasts of the Crohn's disease patients were used to elucidate underlying cellular mechanisms. Caco-2 cells were used to investigate a possible source of PAR1 agonist proteinases. RESULTS: AOM/DSS model showed weight loss, diarrhea, tumor development, inflammation, fibrosis, and increased production of inflammatory cytokines. The ß-diversity, but not α-diversity, of microbiota significantly differed between AOM/DSS and control mice. E5555 alleviated these pathological changes and altered the microbiota ß-diversity in AOM/DSS mice. The thrombin expression was up-regulated in tumor and non-tumor areas, whereas PAR1 mRNA expression was higher in tumor areas compared with non-tumor areas. E5555 inhibited thrombin-triggered elevation of cytosolic Ca2+ concentration and ERK1/2 phosphorylation, as well as IL6-induced signal transducer and activator of transcription 3 (STAT3) phosphorylation in intestinal myofibroblasts. Caco-2 cell-conditioned medium contained immunoreactive thrombin, which cleaved the recombinant protein containing the extracellular domain of PAR1 at the thrombin cleavage site. CONCLUSIONS: PAR1 antagonism is proposed to be a novel therapeutic strategy for treatment of inflammatory bowel disease and its associated carcinogenesis.

Continuous immunotherapy beyond progression in clinical practice for small cell lung cancer.

In non-small-cell lung cancer, continuous immune-checkpoint inhibitors (ICIs) beyond progression are often used in clinical practice. On the other hand, there is almost no data on whether the concept of continuous ICIs beyond progression can be adopted in small-cell lung cancer (SCLC). We describe the effectiveness of continuous ICIs beyond progression in SCLC. Medical courses of SCLC patients treated with chemo-immunotherapy were retrospectively reviewed at our hospital. The study included 36 patients with a median age of 73 years (range 46-83 years) who introduced chemo-immunotherapy between September 2019 and December 2022. Atezolizumab and durvalumab in combination with platinum plus etoposide were administered in 24 and 12 patients, respectively. The overall response rate was 67% and the disease control rate was 86%. The median progression-free survival and time to treatment failure (TTF) were 5.1 and 10.3 months, respectively. The median cycle of ICIs was 5 (range 1-42). The median overall survival was 13.6 months. ICIs were administered beyond progression in 14 (39%) patients: five were treated again with chemo-immunotherapy and local ablative radiotherapy, four with local ablative radiotherapy and continuous ICIs, three with chemo-immunotherapy, and two with continuous ICIs alone. TTF exceeded 12 months in 12 (86%) of the 14 cases, six of which were still on ICIs. Adverse events ≥grade 3 were observed in 21 (58%) patients. A notable TTF suggested a benefit of continuous ICIs beyond progression. The concept could be suitably adopted and provide a favorable prognosis in selected cases of SCLC that were previously regarded as an aggressive malignancy.

Effects of mifepristone on adipocyte differentiation in mouse 3T3-L1 cells.

BACKGROUND: Both glucocorticoid receptor and peroxisome proliferator-activated receptor-γ (PPARγ) play a critical role in adipocyte differentiation. Mifepristone is not only an antagonist of the glucocorticoid receptor but also an agonist of PPARγ. Therefore, the present study investigated the effect of mifepristone on adipocyte differentiation. METHODS: Mouse 3T3-L1 cells were used as a model for adipocyte differentiation. The lipid droplet formation was evaluated with Bodipy493/503 staining and the expression of adipocyte markers [adiponectin and adipocyte fatty acid binding protein-4 (Fabp4)] was evaluated with quantitative PCR and immunoblot analyses for indication of adipocyte differentiation. siRNA and neutralizing antibodies were used to elucidate the molecular mechanism of mifepristone-induced adipocyte differentiation. Luciferase reporter assay was used to examine the effect of mifepristone on the promoter activity of PPAR-response element (PPRE). The DNA microarray analysis was used to characterize the transcriptome of the mifepristone-induced adipocytes. In vivo adipogenic effect of mifepristone was examined in mice. RESULTS: Mifepristone not only enhanced adipocyte differentiation induced by the conventional protocol consisting of insulin, dexamethasone and 3-isobutyl-1-methylxanthine but also induced adipocyte differentiation alone, as evidenced by lipid droplets formation and induction of the expression of adiponectin and Fabp4. These effects were inhibited by an adiponectin-neutralizing antibody and a PPARγ antagonist. Mifepristone activated the promoter activity of PPRE in a manner sensitive to PPARγ antagonist. A principal component analysis (PCA) of DNA microarray data revealed that the mifepristone-induced adipocytes represent some characteristics of the in situ adipocytes in normal adipose tissues to a greater extent than those induced by the conventional protocol. Mifepristone administration induced an increase in the weight of epididymal, perirenal and gluteofemoral adipose tissues. CONCLUSIONS: Mifepristone alone is capable of inducing adipocyte differentiation in 3T3-L1 cells and adipogenesis in vivo. PPARγ plays a critical role in the mifepristone-induced adipocyte differentiation. Mifepristone-induced adipocytes are closer to the in situ adipocytes than those induced by the conventional protocol. The present study proposes a single treatment with mifepristone as a novel protocol to induce more physiologically relevant adipocytes in 3T3-L1 cells than the conventional protocol.

Connexin43, A Promising Target to Reduce Cardiac Arrhythmia Burden in Pulmonary Arterial Hypertension.

While essential hypertension (HTN) is very prevalent, pulmonary arterial hypertension (PAH) is very rare in the general population. However, due to progressive heart failure, prognoses and survival rates are much worse in PAH. Patients with PAH are at a higher risk of developing supraventricular arrhythmias and malignant ventricular arrhythmias. The latter underlie sudden cardiac death regardless of the mechanical cardiac dysfunction. Systemic chronic inflammation and oxidative stress are causal factors that increase the risk of the occurrence of cardiac arrhythmias in hypertension. These stressful factors contribute to endothelial dysfunction and arterial pressure overload, resulting in the development of cardiac pro-arrhythmic conditions, including myocardial structural, ion channel and connexin43 (Cx43) channel remodeling and their dysfunction. Myocardial fibrosis appears to be a crucial proarrhythmic substrate linked with myocardial electrical instability due to the downregulation and abnormal topology of electrical coupling protein Cx43. Furthermore, these conditions promote ventricular mechanical dysfunction and heart failure. The treatment algorithm in HTN is superior to PAH, likely due to the paucity of comprehensive pathomechanisms and causal factors for a multitargeted approach in PAH. The intention of this review is to provide information regarding the role of Cx43 in the development of cardiac arrhythmias in hypertensive heart disease. Furthermore, information on the progress of therapy in terms of its cardioprotective and potentially antiarrhythmic effects is included. Specifically, the benefits of sodium glucose co-transporter inhibitors (SGLT2i), as well as sotatercept, pirfenidone, ranolazine, nintedanib, mirabegron and melatonin are discussed. Discovering novel therapeutic and antiarrhythmic strategies may be challenging for further research. Undoubtedly, such research should include protection of the heart from inflammation and oxidative stress, as these are primary pro-arrhythmic factors that jeopardize cardiac Cx43 homeostasis, the integrity of intercalated disk and extracellular matrix, and, thereby, heart function.