MicroRNA-128-3p Enhances the Chemosensitivity of Temozolomide in Glioblastoma by Targeting c-Met and EMT

Abstract

Temozolomide is a first line anti-tumor drug used for the treatment of patients with Glioblastoma multiforme (GBM). However, the drug resistance to temozolomide limits its clinical application. Therefore, novel strategies to overcome chemoresistance are desperately needed for improved treatment of human GBM. Recent studies have demonstrated that miRNAs are closely related to resistance to cancer chemotherapy. This study aimed to further validate the biological role of miR-128-3p and to investigate whether miR-128-3p can enhance the chemosensitivity of glioblastoma to temozolomide (TMZ) and the underlying mechanisms. The effects of miR-128-3p and TMZ on the proliferation of glioblastoma cells were investigated by cell counting kit-8 (cck8). Transwell and intracerebral invasion assays were applied to determine the effects of the combination of miR-128-3p and TMZ on the invasion and migration of glioblastoma in vitro and in vivo. Flow cytometry was used to detect apoptosis in each group, and immunofluorescence was used to determine the expression levels of EMT-related proteins. RT-PCR and Western-blot were applied to detect EMT-transformed proteins (c-Met, PDGFRα, Notch1, and Slug) and EMT phenotype-associated proteins (Vim, CD44, and E-cadherin) at both mRNA and protein levels. Based on the microRNA.org database, we predicted the target genes of miR-128-3p. The target-relationship between miR-128-3p and c-Met and PDGFRα was verified by dual luciferase reporter gene. The tumor volume, weight and the expression levels of the proteins described above were measured in subcutaneously transplanted tumor model in nude mice. We found that the expression of miR-128-3p was down-regulated in glioblastoma tissue samples and cell lines. miR-128-3p suppressed the proliferation, migration, and invasion of GBM both in vitro and in vivo; miR-128-3p enhanced the therapeutic effect of TMZ via inhibition of proliferation, invasion and migration of glioblastoma cells and induction of apoptosis. Overexpression of miR-128-3p down-regulated the expression levels of EMT-transformed proteins (c-Met, PDGFRα, Notch1 and Slug) to enhance the effect of TMZ. In addition, we found that miR-128-3p targeted and bound c-Met. More importantly, the upregulation of c-Met significantly prompted U87 and U251 cell proliferation. This effect could be abolished when c-Met was silenced. The investigation in tumor bearing nude mice showed that miR-128-3p in combination with TMZ reduced tumor volume and the invasion extent, and increased the sensitivity of glioblastoma to TMZ. miR-128-3p is capable of enhancing the sensitivity of glioblastoma to TMZ through regulating c-Met/EMT. Glioblastoma is the most common intracranial tumor in neurosurgery with poor prognosis and high mortality. TMZ chemotherapy can prolong the overall survival for patients with glioblastoma. However, due to intratumoral heterogeneity, there exist the primary drug-resistant glioblastoma stem cells (GSCs) and epithelial-mesenchymal transition (EMT) cells in glioblastoma, and drug-resistant...

MiR-30c Plays Diagnostic and Prognostic Roles and Mediates Epithelial–mesenchymal Transition (EMT) and Proliferation of Glioma by Affecting Notch1

“…Notch1 plays an instrumental part in glioma cells, with the functions of enhancing stemness and tumorigenicity 33,34 , promoting tumor growth 35 , EMT 36 , and increasing chemotherapy drug resistance 37 . In this study, we used shRNA to inhibit the expression levels of Notch1 in glioma cells, and we revealed that EMT (N-cadherin and Vimentin decreased, E-cadherin increased), proliferation, migration, and invasion ability of cancer cells were signi cantly decreased.…”

Immune Modulatory Short Noncoding RNAs Targeting the Glioblastoma Microenvironment

“…c-MET was recently shown to mediate EMT via activation of Wnt/b-catenin signaling (65). MiR-128-3p targeting c-MET inhibited glioblastoma migration and invasion and enhanced TMZ therapeutic efficacy in vivo (66). Other miRNAs such as miR-34a, miR-144-3p, and miR-562 have been reported to exert activity against glioblastoma proliferation and invasion by also targeting c-MET (66)(67)(68).…”

“…MiR-128-3p targeting c-MET inhibited glioblastoma migration and invasion and enhanced TMZ therapeutic efficacy in vivo (66). Other miRNAs such as miR-34a, miR-144-3p, and miR-562 have been reported to exert activity against glioblastoma proliferation and invasion by also targeting c-MET (66)(67)(68). Hence, these therapeutic miRNAs and c-MET siRNAs could be used to treat glioblastoma by means of suppressing tumor invasion and EMT.…”

FXYD2 mRNA expression represents a new independent factor that affects survival of glioma patients and predicts chemosensitivity of patients to temozolomide

“…In fact, the average survival time for glioblastoma patients is only 14 months [ 4 ]. Due to the heterogeneity of gliomas [ 5 ] and different drug resistance to temozolomide (TMZ) [ 6 – 9 ], the prognosis of different glioma patients is quite different. Meanwhile, the application of high-throughput technology for the molecular classification of gliomas as well as for screening differentially expressed genes and drug resistance genes has become a research hotspot to facilitate the development of corresponding targeted drugs.…”