Portrayal of EMT Like Process in Human Glioma and Its Impediment by Rabeprazole to Combat Glioma Growth and Temozolomide Resistance

Abstract

Background: Epithelial to mesenchymal transition (EMT) is a well-documented process in other cancers; its recognition in glioma is relatively new and lacking clinical and therapeutic significance. Methods: To characterize the EMT like process in glioma we investigated the expression profile of EMT associated proteins in clinical biopsies through western and immunohistochemistry and correlated with various clinicopathological features and the cancer genome atlas (TCGA) dataset. Further, we explored the anticancer efficacy of rabeprazole by in-vitro and in-vivo and its therapeutic relevance to EMT and temozolomide chemosensitization through multiple cell-based assays, western blotting, and confocal imaging. Findings: The expression analysis of EMT associated proteins and TCGA dataset revealed non-canonical expression of E-cadherin or N-cadherin and upregulation of GFAP, vimentin, and β-catenin in human glioma. The increased EMT proteins may attribute to glioma malignancy and poor prognosis. The in-vitro study unveils rabeprazole treatment attenuated glioma cell growth, cell migration, and induced apoptosis. Rabeprazole exposure suppressed EMT by repressing NF-κB signaling and/or inhibiting Akt/GSK3β phosphorylation. Further, the in-vivo studies confer restricted tumor growth in the confluence of EMT inhibition. We also showed temozolomide sensitizing effect of rabeprazole on temozolomide resistant cell line. Interpretation: We evidenced the clinical association of EMT like process in glioma malignancy and poor prognosis and its therapeutic relevance to rabeprazole along with rabeprazole anticancer and chemosensitization efficacy. Funding Statement: Authors acknowledged financial assistance of Department of Science and technology (DST- India) (Grant no: SB/EMEQ-257/2013, SR/CSRI/196/2016) and Department of Biotechnology (DBT-India) (Grant No. BT/PR18168/MED/29/1064/2016, BT/PR13111/MED/29/149/2009) for lab funding. D.B. thanks, Department of Biotechnology (DBT-India) for student fellowship (Award no: DBT/2013/UOH/79). Declaration of Interests: Written informed consent was obtained from all participants included in the study. Ethics Approval Statement: Institutional Ethics Committee (IEC) (reference number UH/IEC/2016/180) and Institutional Animal Ethics Committee (IAEC) (reference number UH/IAEC/PPB/2017-I/P7), University of Hyderabad, Hyderabad (500 046) approved all procedures involving human tissue and animal related experiments.