MicroRNA-203-3p inhibits the proliferation, invasion and migration of pancreatic cancer cells by downregulating fibroblast growth factor 2.

Aberrant expression of fibroblast growth factor 2 (FGF2) is a major cause of poor prognosis in patients with pancreatic cancer. MicroRNA (miRNA/miR) miR-203-3p is a newly identified miRNA that can affect the biological behavior of tumors. The present study investigated the function of miR-203-3p on the regulation of FGF2 expression, and its role in pancreatic cancer cell proliferation, apoptosis, invasion and migration. Reverse transcription-quantitative PCR was used to determine the mRNA expression levels of miR-203-3p and FGF2 in vitro. Cell Counting Kit-8, Annexin V-APC/7-AAD double-staining Apoptosis Detection kit, wound healing and Transwell assays were used to determine the proliferation, apoptosis, migration and invasion of pancreatic cancer cells. The binding of miR-203-3p to FGF2 was assessed by a luciferase reporter assay. The results demonstrated that miR-203-3p expression was downregulated in pancreatic cancer cells. Gain- and loss-of-function experiments indicated that miR-203-3p inhibited the proliferation, migration and invasion, and promoted the apoptosis of pancreatic cancer cells in vitro. In addition, it was found that alteration of miR-203-3p abolished the promoting effects of FGF2 on pancreatic cancer cells. The present study demonstrated that FGF2 significantly promoted the proliferation, invasion and migration of pancreatic cancer cells. The mechanism involved the binding of miR-203-3p to the 3'-untranslated region of FGF2 mRNA, resulting in the downregulation of FGF2. In conclusion, miR-203-3p inhibited FGF2 expression, regulated the proliferation and inhibited the invasion and migration of pancreatic cancer cells.

Mitochondrial redox-driven mitofusin 2 S-glutathionylation promotes neuronal necroptosis via disrupting ER-mitochondria crosstalk in cadmium-induced neurotoxicity.

Reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress and mitochondrial dysfunction are known to affect the structural and functional damage in the neural system. Cadmium (Cd) is an environmental contaminant that is widely found in numerous environmental matrices and exhibits potential neurotoxic risk. However, it remains unclear how mitochondrial redox status induces, and whether Cd destabilizes, the ER-mitochondria crosstalk to have a toxic effect on the nervous system. Herein, in our present study, bioinformatics analysis revealed an important role of protein interaction and mitochondrial machinery in brain samples from Alzheimer's disease (AD) patients. Furthermore, we established a neurotoxicity model in vivo and in vitro induced by cadmium chloride (CdCl2). We demonstrated that CdCl2 exposure disrupts the balance in mitochondrial redox represented by enhanced mitochondrial ROS (mitoROS) levels, which enhance mitofusin 2 (Mfn2) S-glutathionylation and interrupt the mitochondria-associated ER membranes (MAMs) for crosstalk between the ER and mitochondria to induce neuronal necroptosis. Mechanistically, it was shown that CdCl2 exposure significantly enhances the mitochondria-associated degradation (MAD) of Mfn2 via S-glutathionylation, which inhibits Mfn2 localization to the MAMs and subsequently leads to the formation of the RIPK1-RIPK3-p-MLKL complex (a key component of the necrosome) at MAMs, to promote neuronal necroptosis. Furthermore, the glutaredoxin 1 (Grx1) catalyzed and Mfn2 overexpression restored S-glu-Mfn2, MAMs perturbation, necrosome formation, and necroptosis in neurons induced by CdCl2 exposure in vitro. Moreover, the intervention with antioxidants to reduce mitochondrial redox, such as N-acetyl-l-cysteine (NAC) and mitochondria-targeted antioxidant Mito-TEMPO, reduced the S-glutathionylation of Mfn2 involved in the antagonism of CdCl2-induced necroptosis and neurotoxicity in vivo and in vitro. Taken together, our results are the first time to demonstrate that S-glutathionylation of Mfn2 promotes neuronal necroptosis via disruption of ER-mitochondria crosstalk in CdCl2-induced neurotoxicity, providing the novel mechanistic insight into how hazardous chemical-induced adverse effects in various organs and tissues could be interpreted by intraorganellar pathways under the control of MAMs components in neurons.

Cyclooxygenase-2 modulates ER-mitochondria crosstalk to mediate superparamagnetic iron oxide nanoparticles induced hepatotoxicity: an in vitro and in vivo study.

Mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) are central microdomains of the ER that interact with mitochondria. MAMs provide an essential platform for crosstalk between the ER and mitochondria and play a critical role in the local transfer of calcium (Ca2+) to maintain cellular functions. Despite the potential uses of superparamagnetic iron oxide nanoparticles (SPIO-NPs) in biomedical applications, the hepatotoxicity of these nanoparticles (NPs) is not well characterized and little is known about the involvement of MAMs in ER-mitochondria crosstalk. We studied SPIO-NPs-associated hepatotoxicity in vitro and in vivo. In vitro, human normal hepatic L02 cells were exposed to SPIO-NPs (2.5, 7.5, and 12.5 µg/mL) for 6 h and SPIO-NPs (12.5 µg/mL) was found to induce apoptosis. In vivo, SPIO-NPs induced liver injury when mice were intravenously injected with 20 mg/kg body weight SPIO-NPs for 24 h. Based on both in vitro and in vivo studies, we found that the structure and Ca2+ transport function of MAMs were perturbated and an accumulation of cyclooxygenase-2 (COX-2) in MAMs fractions was increased upon treatment of SPIO-NPs. The interaction between COX-2 and the components of MAMs, in terms of IP3R-GRP75-VDAC1 complex, was also revealed. Furthermore, the role of COX-2 in SPIO-NPs-associated hepatotoxicity was investigated by modifying the expression of COX-2. We demonstrated that COX-2 increases the structural and functional ER-mitochondria coupling and enhances the efficacy of ER-mitochondria Ca2+ transfer through the MAMs, thus sensitizing hepatocytes to a mitochondrial Ca2+ overload-dependent apoptosis. Taken together, our findings link SPIO-NPs-triggered hepatotoxicity with ER-mitochondria Ca2+ crosstalk which is mediated by COX-2 and provide mechanistic insight into the impact of interorganelle ER-mitochondria communication on hepatic nanotoxicity.