Human cytomegalovirus infection enhances invasiveness and migration of glioblastoma cells by epithelial-to-mesenchymal transition

Xiuli Zhu; Bo Hu; Ming Hu; Dongmeng Qian; Bin Wang

Human cytomegalovirus infection enhances invasiveness and migration of glioblastoma cells by epithelial-to-mesenchymal transition

Int J Clin Exp Pathol. 2020 Oct 1;13(10):2637-2647. eCollection 2020.

Authors

Xiuli Zhu¹, Bo Hu², Ming Hu¹, Dongmeng Qian¹, Bin Wang¹

Affiliations

¹ Department of Pathogenic Biology, College of Basical Medicine, Qingdao University Qingdao, P. R. China.
² Department of Thoracic Surgery, Municipal Hospital Affiliated to Qingdao University Qingdao, P. R. China.

PMID: 33165445
PMCID: PMC7642705

Abstract

Objective: This study aims to investigate the effect of human cytomegalovirus (HCMV) infection on epithelial-to-mesenchymal transition (EMT) in glioblastoma cells and the possible underlying molecular mechanism.

Methods: We established primary cell cultures and measured the expression of the HCMV immediate early protein (IE1) to determine HCMV infection by immunohistochemical assays. Human glioma cells were divided into four groups: primary HCMV-positive, primary HCMV-negative, HCMV-positive U87, and HCMV-negative U87 cells. Cells were treated with transforming growth factor (TGF-β1, 5 ng/ml) to induce EMT. Morphologic changes of the cells were observed microscopically at 0, 24, 48, and 72 h post TGF-β1 treatment. Following EMT induction, E-cadherin and vimentin were detected using RT-PCR. Expression of MMP-2, E-cadherin, and vimentin was measured by western blotting. The invasiveness of glioma cells was also measured using the Transwell migration assay and a wound-healing assay.

Results: Morphologic changes in primary glioblastoma cells and U87 cells were observed at different times after exposure to TGF-β1, and the extent of these changes was greater in HCMV-positive compared with HCMV-negative cells. Following exposure to TGF-β1, the transcription of E-cadherin was significantly lower in HCMV-positive primary cells and U87 cells compared with HCMV-negative cells (P<0.01), which was consistent with the results of western blotting. The expression levels of vimentin were also elevated in HCMV-positive cells at 48 and 72 h. HCMV-positive U87 cells were significantly more invasive and migratory than HCMV-positive primary cells. TGF-β1 and HCMV were observed to accelerate EMT and cell invasion by the Jun N-terminal kinase (JNK) pathway. Collectively, our findings indicate that HCMV and TGF-β1 promoted cell invasion and migration in glioma cells by the JNK pathway.

Conclusion: HCMV infection can promote EMT and strengthen the invasiveness of glioma cells.

Keywords: Human cytomegalovirus; epithelial-mesenchymal transition; glioblastoma; transforming growth factor-β1.