Expression of Bcl-2, Bcl-x, and Bax proteins in astrocytomas in relation to patient survival

MicroRNA-27a-3p Downregulation Inhibits Inflammatory Response and Hippocampal Neuronal Cell Apoptosis by Upregulating Mitogen-Activated Protein Kinase 4 (MAP2K4) Expression in Epilepsy: In Vivo and In Vitro Studies

BACKGROUND This study aimed to discover the effect and mechanism of microRNA-27a-3p (miR-27a-3p) in epilepsy. MATERIAL AND METHODS To perform our investigation, in vivo and in vitro models of epilepsy were induced using kainic acid (KA). Expression of miR-27a-3p in the hippocampus of epileptic rats or normal rats or neuronal cells was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Racine score was used to assess seizures in epileptic rats. Cell viability and cell apoptosis were analyzed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was performed to detect inflammatory factors expression. RESULTS Significantly higher expression of miR-27a-3p in the hippocampus of epileptic rats and in KA-induced neurons was observed. We found that miR-27a-3p inhibitor alleviated seizures in epileptic rats. miR-27a-3p inhibitor also inhibited apoptosis of hippocampal neurons in epileptic rats, promoted Bcl2 expression, and decreased Bax and Caspase3 expression. The results showed that miR-27a-3p inhibitor effectively reduced the expression levels of interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor-alpha (TNF-alpha) in hippocampal tissues of epileptic rats. Dual luciferase reporter assay showed that mitogen-activated protein kinase 4 (MAP2K4) was a direct target of miR-27a-3p. miR-27a-3p inhibitor significantly promoted the cell viability of KA-induced neurons, inhibited cell apoptosis, promoted the expression of Bcl-2, and decreased Bax and Caspase3 expression, and all these changes were abolished by MAP2K4-siRNA co-transfection. CONCLUSIONS Our preliminary findings indicated that miR-27a-3p inhibitor protected against epilepsy-induced inflammatory response and hippocampal neuronal apoptosis by targeting MAP2K4.

Lidocaine protects H9c2 cells from hypoxia-induced injury through regulation of the MAPK/ERK/NF-κB signaling pathway

The aim of the present study was to investigate the effect of Lidocaine on hypoxia-induced injury in cardiomyoblasts whilst exploring the associated molecular mechanism. In the present study, hypoxia was induced in H9c2 cells to establish an in vitro model of myocardial infarction. The cells were treated with lidocaine (0.5, 1, 5, 10 mM) for 48 h under hypoxic conditions. Cell viability and apoptosis levels were determined by MTT assay and flow cytometry, and ELISA was used to measure the levels of inflammatory cytokines released. A creatine kinase isoenzyme/cardiac troponin I detection kit was used to show that lidocaine significantly reduced hypoxia-induced cardiac troponin 1 and creatine kinase-muscle/brain release in a dose-dependent manner. Mitochondrial viability staining suggested that lidocaine significantly enhanced mitochondrial viability under hypoxic conditions. Lidocaine also significantly reduced hypoxia-induced apoptosis and increased H9c2 viability in a dose-dependent manner. Additionally, under hypoxic conditions, lidocaine dose-dependently promoted Bcl-2 expression, while decreasing Bax and caspase-3 expression in H9c2 cells. ELISA and reverse transcription quantitative PCR were used to detect the levels of tumor necrosis factor (TNF-α), interleukin (IL)-1β and IL-6 released by H9c2 cells. Results showed that lidocaine markedly reduced the hypoxia-induced expression levels of IL-1β, TNF-α and IL-6 in a dose-dependent manner. In addition, protein levels of phosphorylated (p)-ERK1/2 and NF-κB p-p65 were analyzed by western blotting, and results indicated that lidocaine significantly increased the protein levels of p-ERK1/2 and decreased the protein level of NF-κB p-p65 in a dose-dependent manner under hypoxic conditions. These data suggested that lidocaine might protect cardiomyoblasts from hypoxia-induced injury via activation of the mitogen activated protein kinase/ERK/NF-κB signaling pathway.

Lower expression of Bax predicts poor clinical outcome in patients with glioma after curative resection and radiotherapy/chemotherapy

BACKGROUND

The prognosis in patients with gliomas after surgical resection followed by radiotherapy and/or chemotherapy is still very poor. The pro-apoptotic protein Bax, a short-lived protein in cancers, plays important roles in the sensitivity of glioma cells to spontaneous and therapy-induced apoptosis but and its prognostic value in gliomas is unknown.

METHODS

By an immunohistochemical method, we determined Bax protein expression from 96 patients with gliomas after curative resection. Two statistical analyses were performed to evaluate the prognostic significance of Bax protein: an independent continuous and a multivariate categorical analysis, with test/validation set-defined cut points, and Kaplan-Meier estimated outcome measures of overall survival (OS) and relapse-free survival (RFS).

RESULTS

Bax protein levels in glioblastoma were significantly decreased compared with grade II gliomas. Lower levels of Bax expression confer worse OS (continuous P = 0.025; categorical P = 0.003) and RFS (continuous P = 0.014; categorical P < 0.0001) and negatively correlate with the grades of gliomas. Patients underwent radiotherapy followed by surgical resection showed significantly increased OS (median = 45 vs. 17 months) and RFS (median = 39 vs. 16 months). Patients with higher levels of Bax and radiotherapy showed greatly increased survival rates (median OS = 66 months and median RFS = 105 months). Lower expression of Bax also confers inferior clinical outcome for gliomas patients after chemotherapy with temozolomide (OS and RFS P < 0.0001).

CONCLUSION

Decreased expression of Bax correlates with poor clinical outcome in patients with gliomas. We propose that Bax protein levels can be used as a reliable prognostic marker for risk-stratify patients with gliomas after curative resection and radiotherapy and/or chemotherapy.

Effects of microRNA-129 and its target gene c-Fos on proliferation and apoptosis of hippocampal neurons in rats with epilepsy via the MAPK signaling pathway

This study aims to investigate the effect of microRNA-129 (miR-129) on proliferation and apoptosis of hippocampal neurons in epilepsy rats by targeting c-Fos via the MAPK signaling pathway. Thirty rats were equally classified into a model group (successfully established as chronic epilepsy models) and a normal group. Expression of miR-129, c-Fos, bax, and MAPK was detected by RT-qPCR and Western blotting. Hippocampal neurons were assigned into normal, blank, negative control (NC), miR-129 mimic, miR-129 inhibitor, siRNA-c-Fos, miR-129 inhibitor+siRNA-c-Fos groups. The targeting relationship between miR-129 and c-Fos was predicted and verified by bioinformatics websites and dual-luciferase reporter gene assay. Cell proliferation after transfection was measured by MTT assay, and cell cycle and apoptosis by flow cytometry. c-Fos is a potential target gene of miR-129. Compared with the normal group, the other six groups showed a decreased miR-129 expression; increased expression of expression of c-Fos, Bax, and MAPK; decreased proliferation; accelerated apoptosis; more cells arrested in the G1 phase; and fewer cells arrested in the S phase. Compared with the blank and NC groups, the miR-129 mimic group and the siRNA-c-Fos group showed decreased expression of c-Fos, Bax, and MAPK, increased cells proliferation, and decreased cell apoptosis, fewer cells arrested in the G1 phase and more cells arrested in the S phase. However, the miR-129 inhibitor groups showed reverse consequences. This study suggests that miR-129 could inhibit the occurrence and development of epilepsy by repressing c-Fos expression through inhibiting the MAPK signaling pathway.