Resveratrol restores sensitivity of glioma cells to temozolamide through inhibiting the activation of Wnt signaling pathway.

Malignant gliomas are aggressive primary neoplasms that originate in the glial cells of the brain or the spine with notable resistance to standard treatment options. We carried out the study with the aim to shed light on the sensitization of resveratrol to temozolomide (TMZ) against glioma through the Wnt signaling pathway. Initially, glioma cell lines with strong resistance to TMZ were selected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Then, the glioma cells were subjected to resveratrol, TMZ, Wnt signaling pathway inhibitors, and activators. Cell survival rate and inhibitory concentration at half maximum value were detected by MTT, apoptosis by flow cytometry, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, in vitro proliferation by hanging drop method and ß-catenin translocation into nuclei by TOP/FOP-FLASH assay. The expressions of the Wnt signaling pathway-related and apoptosis-related factors were determined by western blot analysis. Nude mice with glioma xenograft were established to detect tumorigenic ability. Glioma cell lines T98G and U138 which were highly resistant to TMZ were selected for subsequent experiments. Resveratrol increased the efficacy of TMZ by restraining cell proliferation, tumor growth, and promoting cell apoptosis in glioma cells. Resveratrol inhibited Wnt2 and ß-catenin expressions yet elevated GSK-3ß expression. Moreover, the Wnt signaling pathway participates in the sensitivity enhancing of resveratrol to TMZ via regulating O 6 -methylguanine-DNA methyltransferase (MGMT) expression. Resveratrol sensitized TMZ-induced glioma cell apoptosis by repressing the activation of the Wnt signaling pathway and downregulating MGMT expression, which may confer new thoughts to the chemotherapy of glioma.

MicroRNA-499a decelerates glioma cell proliferation while accelerating apoptosis through the suppression of Notch1 and the MAPK signaling pathway.

As the most common and lethal of intracranial tumors, glioma accounts for 81% of all malignant brain tumors. Research data have identified the role of microRNAs (miRs) as functional suppressors in the progression of Glioma. The present study aimed to, ascertain as to whether microRNA-499a (miR-499a) influences cell proliferation and apoptosis through the MAPK signaling pathway by targeting Notch1 in glioma. Both glioma and adjacent tissues between 2012-2016, were obtained from People's Hospital of Zhengzhou University (Henan Provincial People's Hospital). The collected glioma cells were treated with miR-449a mimic, miR-449a inhibitor, siRNA-Notch1, or SB230580 (an inhibitor of the MAPK signaling pathway). Verification of the targeting effect of miR-449a on Notch1 was provided by a dual-luciferase reporter gene assay. The expressions of miR-449a, Notch1, p38 mitogen-activated protein kinase (p38MAPK), extracellular regulated protein kinases (ERK1/2), B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (bax), CyclinD1, and phosphorylation of p38MAPK (p-p38MAPK) and ERK1/2 (p-ERK1/2) in tissues and cells were detected by means of reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis methods. Cellular processes of proliferation, cell cycle and apoptosis were evaluated by MTT and BrdU assays as well as flow cytometry, respectively. Notch1 was subsequently identified to be a target gene of miR-499a. After the cells were treated with miR-449a mimic, siRNA-Notch1 or SB230580, decreased expressions of Notch1, Bcl-2, CyclinD1, ERK1/2 and p-ERK1/2, cell proliferation as well as cells arrested at the S stage with elevated expressions levels of p38MAPK, p-p38MAPK, Bax, as well as increased cell apoptosis and number of cells arrested in G0/G1 stage were assessed. Taken together, based on the evidence obtained from the present study, assertions were subsequently made suggesting that MiR-499a targeted-inhibition of Notch1 may be a promising future therapeutic strategy for glioma treatment, by means of overexpressing of miR-499a resulting in the inhibition of glioma cell proliferation and promotion of cell apoptosis through suppression of the MAPK signaling pathway by decreasing Notch1.