Nrf2 is overexpressed in pancreatic cancer: implications for cell proliferation and therapy

<p>Abstract</p> <p>Background</p> <p>Nrf2 is a key transcriptional regulator of a battery of genes that facilitate phase II/III drug metabolism and defence against oxidative stress. Nrf2 is largely regulated by Keap1, which directs Nrf2 for proteasomal degradation. The Nrf2/Keap1 system is dysregulated in lung, head and neck, and breast cancers and this affects cellular proliferation and response to therapy. Here, we have investigated the integrity of the Nrf2/Keap1 system in pancreatic cancer.</p> <p>Results</p> <p>Keap1, Nrf2 and the Nrf2 target genes AKR1c1 and GCLC were detected in a panel of five pancreatic cancer cell lines. Mutation analysis of <it>NRF2 </it>exon 2 and <it>KEAP1 </it>exons 2-6 in these cell lines identified no mutations in <it>NRF2 </it>and only synonomous mutations in <it>KEAP1</it>. RNAi depletion of Nrf2 caused a decrease in the proliferation of Suit-2, MiaPaca-2 and FAMPAC cells and enhanced sensitivity to gemcitabine (Suit-2), 5-flurouracil (FAMPAC), cisplatin (Suit-2 and FAMPAC) and gamma radiation (Suit-2). The expression of Nrf2 and Keap1 was also analysed in pancreatic ductal adenocarcinomas (n = 66 and 57, respectively) and matching normal benign epithelium (n = 21 cases). Whilst no significant correlation was seen between the expression levels of Keap1 and Nrf2 in the tumors, interestingly, Nrf2 staining was significantly greater in the cytoplasm of tumors compared to benign ducts (P < 0.001).</p> <p>Conclusions</p> <p>Expression of Nrf2 is up-regulated in pancreatic cancer cell lines and ductal adenocarcinomas. This may reflect a greater intrinsic capacity of these cells to respond to stress signals and resist chemotherapeutic interventions. Nrf2 also appears to support proliferation in certain pancreatic adenocarinomas. Therefore, strategies to pharmacologically manipulate the levels and/or activity of Nrf2 may have the potential to reduce pancreatic tumor growth, and increase sensitivity to therapeutics.</p

Characterisation of the mechanisms involved in the transcellular transport of monocarboxylates across the equine large intestine

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Characterization of butyrate transport across the luminal membranes of equine large intestine

New Findings: What is the central question of this study? Butyrate, a product of colonic microbial fermentation of dietary fibre (grass), is a major source of energy for the horse and plays an important role in maintaining the health of the intestine. What are the properties of the membrane protein and what is the mechanism by which butyrate is absorbed in equine large intestine (colon)? What is the main finding and its importance? We have identified the mechanism of and membrane protein involved in butyrate transport in equine large intestine. This knowledge will allow rational approaches to the design of dietary formulations to enhance butyrate production and absorption in equine colon, in order to provide more energy for the horse and maintain its gut health. The diet of the horse, pasture forage (grass), is fermented by the equine colonic microbiota to short‐chain fatty acids, notably acetate, propionate and butyrate. Short‐chain fatty acids provide a major source of energy for the horse and contribute to many vital physiological processes. We aimed to determine both the mechanism of butyrate uptake across the luminal membrane of equine colon and the nature of the protein involved. To this end, we isolated equine colonic luminal membrane vesicles. The abundance and activity of cysteine‐sensitive alkaline phosphatase and villin, intestinal luminal membrane markers, were significantly enriched in membrane vesicles compared with the original homogenates. In contrast, the abundance of GLUT2 protein and the activity of Na+–K+‐ATPase, known markers of the intestinal basolateral membrane, were hardly detectable. We demonstrated, by immunohistochemistry, that monocarboxylate transporter 1 (MCT1) protein is expressed on the luminal membrane of equine colonocytes. We showed that butyrate transport into luminal membrane vesicles is energized by a pH gradient (out < in) and is not Na+ dependent. Moreover, butyrate uptake is time and concentration dependent, with a Michaelis–Menten constant of 5.6 ± 0.45 mm and maximal velocity of 614 ± 55 pmol s−1 (mg protein)−1. Butyrate transport is significantly inhibited by p‐chloromercuribenzoate, phloretin and α‐cyano‐4‐hydroxycinnamic acid, all potent inhibitors of MCT1. Moreover, acetate and propionate, as well as the monocarboxylates pyruvate and lactate, also inhibit butyrate uptake. Data presented here support the conclusion that transport of butyrate across the equine colonic luminal membrane is predominantly accomplished by MCT1

Protective potential of mesenchymal stem cells against COVID-19 during pregnancy

SARS-CoV-2 causes COVID-19. COVID-19 has led to severe clinical illnesses and an unprecedented death toll. The virus induces immune inflammatory responses specifically cytokine storm in lungs. Several published reports indicated that pregnant females are less likely to develop severe symptoms compared with non-pregnant. Putative protective role of maternal blood circulating fetal mesenchymal stem cells (MSCs) has emerged and have been put forward as an explanation to alleviated symptoms. MSCs with immune-modulatory, anti-inflammatory and anti-viral roles, hold great potential for the treatment of COVID-19. MSCs could be an alternative to treat infections resulting from the SARS-CoV-2 and potential future outbreaks. This review focuses on the MSCs putative protective roles against COVID-19 in pregnant females

Identification of SPP1 as a Prognostic Biomarker and Immune Cells Modulator in Urothelial Bladder Cancer: A Bioinformatics Analysis

Secreted phosphoprotein-1 (SPP1) expression is differentially altered in many malignancies and could serve as a potential prognostic biomarker. Recent findings indicated that SPP1 possesses a broader role in bladder cancer (BC) pathogenesis than previously envisioned; however, the underlying mechanisms governing its expression, cellular localization, prognostic value and immune-related role in bladder cancer remain poorly understood. The expression and the prognosis value of SPP1 were assessed using immunohistochemistry (IHC) staining on a tissue microarray. SPP1 expression was correlated with the clinicopathological parameters, and survival analysis was calculated using a Kaplan–Meier plotter. Bioinformatics analysis of TCGA data was queried using UALCAN, CIBERSORT and TIMER datasets to decipher the biological processes enrichment pattern, protein–protein interactions and characterize tumor-infiltrating immune cells, respectively. IHC revealed that SPP1 expression is significantly associated with tumor type, stage, grade and smoking status. The Kaplan–Meier survival curve showed that low SPP1 expression is an unfavorable prognostic indicator in bladder cancer patients (p = 0.02, log-rank). The significant increased expression of the SPP1 level is associated with evident hypomethylation of the gene promoter in cancer compared to normal tissues in the TCGA-bladder dataset. Missense mutation is the most frequent genetic alteration of the SPP1 gene. Protein–protein interactions demonstrated that SPP1 shares the same network with many important genes and is involved in many signaling pathways and biological processes. TIMER reported a significant correlation between SPP1 expression and multiple immune cells infiltration. Furthermore, the expression of SPP1 was found to be positively correlated with a number of immune checkpoint genes such as PD-1 and CTLA4. The current investigation indicates that the SPP1 protein could serve as a prognostic biomarker and merit further investigation to validate its clinical usefulness in patients with bladder cancer