ABSTRACT
This study aims to explore how microRNA-133a (miR-133a) affects cell apoptosis and radio-sensitivity by targeting EGFR via regulating MEK/ERK pathway in esophageal cancer (EC). A total of 358 EC patients were selected and assigned into the resistant and sensitive groups. Human EC KYSE 150 cell line was assigned into the blank, negative control (NC), miR-133a mimic, miR-133a inhibitors, si-EGFR, miR-133a inhibitors + si-EGFR groups after transfection. MiR-133a and EGFR mRNA expressions were detected by qRT-PCR and EGFR, MEK/ERK pathway-related protein expressions were detected by Western blotting. The radio-sensitivity and cell apoptosis were testified by clone formation and flow cytometry. MiR-133a was up-regulated but EGFR was down-regulated in the sensitive group than in the resistant group. Compared with the blank and NC groups, the miR-133a mimic and si-EGFR groups exhibited increased cell apoptosis rate but decreased EGFR, p-MEK1/2, and p-ERK1/2 protein expressions; while opposite trend was observed in the miR-133a inhibitors group. Compared with the miR-133a inhibitors group, the miR-133a inhibitors + si-EGFR group presented reduced cell survival rate, EGFR, p-MEK1/2, and p-ERK1/2 protein expressions but increased cell apoptosis rate. These results indicated that miR-133a could inhibit the MEK/ERK pathway to promote cell apoptosis and enhance radio-sensitivity by targeting EGFR in EC. J. Cell. Biochem. 118: 2625-2634, 2017. © 2017 Wiley Periodicals, Inc.
Subject(s)
Apoptosis , ErbB Receptors/metabolism , Esophageal Neoplasms , MAP Kinase Signaling System , MicroRNAs/biosynthesis , Neoplasm Proteins/metabolism , RNA, Neoplasm/biosynthesis , Radiation Tolerance , Up-Regulation , Aged , Cell Line, Tumor , ErbB Receptors/antagonists & inhibitors , ErbB Receptors/genetics , Esophageal Neoplasms/genetics , Esophageal Neoplasms/metabolism , Esophageal Neoplasms/pathology , Esophageal Neoplasms/therapy , Female , Humans , Male , MicroRNAs/antagonists & inhibitors , MicroRNAs/genetics , Middle Aged , Neoplasm Proteins/antagonists & inhibitors , Neoplasm Proteins/genetics , RNA, Neoplasm/antagonists & inhibitors , RNA, Neoplasm/geneticsABSTRACT
The apoptotic or necrotic death of renal tubule epithelial cells is the main pathogenesis of renal ischemia-reperfusion-induced acute kidney injury (AKI). Pyroptosis is a programmed cell death pathway that depends on the activation of the caspase cascade and IL-1 cytokine family members. However, the role of pyroptosis in AKI induced by ischemia-reperfusion remains unclear. In this study, we found that the levels of the pyroptosis-related proteins, including caspase-1, caspase-11, and IL-1ß, were significantly increased after 6 h of renal ischemia-reperfusion injury (IRI) and peaked at 12 h after IRI. Enhanced pyroptosis was accompanied by elevated renal structural and functional injury. Similarly, hypoxia-reoxygenation injury (HRI) also induced pyroptosis in renal tubule epithelial NRK-52E cells, which was characterized by increased pore formation and elevated lactate dehydrogenase release. In addition, obvious upregulation of the endoplasmic reticulum (ER) stress biomarkers glucose-regulated protein 78 and C/EBP homologous protein (CHOP) preceded the incidence of pyroptosis in cells treated with IRI or HRI. Pretreatment with a low dose of tunicamycin, an inducer of ER stress, relieved IRI-induced pyroptosis and renal tissue injury. Silencing of CHOP by small interfering RNA significantly decreased HRI-induced pyroptosis of NRK-52E cells, as evidenced by reduced caspase-11 activity and IL-1ß generation. Therefore, we conclude that pyroptosis of renal tubule epithelial cells is a key event during IRI and that CHOP-caspase-11 triggered by overactivated ER stress may be an essential pathway involved in pyroptosis.
