SPINK1-induced amelioration of impaired autophagy contributes to suppression of trypsinogen activation in a model of acute pancreatitis

AbstractSPINK1 has been regarded as a reversible trypsinogen inhibitor for the inappropriate activation of trypsin, a key step in the initiation of acute pancreatitis (AP). However, the mechanisms of its action remains largely unclear and controversial. Here, we reported an unexpected effects of SPINK1 on inhibiting trypsinogen activation through the regulation of impaired autophagy in cerulein-stimulated AR42J cells, a well-established in vitro model of acute pancreatitis. Firstly, we found that the impaired autophagic flux was induced and trypsinogen activity enhanced in the above setting. Then, we showed that SPINK1 overexpression could inhibit the level of increased autophagic activity, improving the hindered autophagy flux, and significantly decreased the trypsinogen activity, whereas shRNA-caused downregulation of SPINK1 exacerbated the impairment of autophagic flux and trypsin activity, in the same cerulein-processed cells. More importantly, the trypsinogen activation in this model could be ameliorated by 3-Methyladenine(3-MA), an autophagy inhibitor. Thus, this study revealed, possibly for the first time, that SPINK1 greatly blocked the trypsinogen activation possibly through the modulation of impaired autophagy in cerulein-induced in vitro model of acute pancreatitis.</jats:p

MicroRNA-4316 inhibits gastric cancer proliferation and migration via directly targeting VEGF-A

Abstract Background and aims microRNAs (miRNAs) have been reported to regulate proliferation and migration by down-regulating the expression of target genes. The aims of this study were to investigate whether miR-4316 inhibited proliferation and migration by downregulating vascular endothelial growth factor A (VEGF-A) and its clinical significance in gastric cancer (GC). Methods The clinical tissues of the GC patients for miR-4316 and VEGF-A were detected by qRT-PCR. The protein levels of VEGF-A and c-Met were determined by western blotting. Cell Proliferation, migration, and colony forming assays were conducted to show whether miR-4316 affects proliferation by CCK-8, migration by transwell, wound healing and colony formation assays. The bioinformatic methods and luciferase reporter assay were applied to detect the relationship between miRNA and VEGF-A on its targeting 3-untranslated regions (3-UTRs). CCK-8, colony formation, wound healing, and transwell assay were performed to explore the function of miR-4316. Results The results of qRT-PCR indicated that miR-4316 expression level was significantly downregulated in human GC tissues and GC cell lines compared with their control. miR-4316 inhibited proliferation, migration and colony formation in GC cell lines by reducing VEGF-A. And western blot results indicated that miR-4316 significantly inhibited GC through repressing VEGF-A and c-Met. The investigation of Luciferase assay indicated that VEGF-A is a direct target gene of miR-4316. Conclusions miR-4316 suppressed proliferation and migration of GC through the VEGF-A gene. MiR-4316 acts as a tumor suppressor by targeting VEGF-A and this indicated that MiR-4316 might be a potential therapeutic target for GC. </jats:sec