Small T Oncoprotein of Merkel Cell Polyomavirus Attenuates Cisplatin-Induced Apoptosis and Enhances E1, E6/E7, MMP-1, and Ki-67 Expression in HeLa Cervical Cancer Cells

Authors:
Open Access
Publisher website
Google Scholar
Abstract
Purpose: Cervical cancer (CxCa), is mainly caused by high-risk human papillomaviruses (hrHPV), which disrupt the regulation of p53 and pRb, leading to uncontrolled cell growth and cancer progression. Co-infection with human polyomaviruses like MCPyV has been observed in some HPV-positive cases, suggesting a potential combined effect on tumor development. Cisplatin is commonly used for advanced CxCa, but resistance, often due to p53 disruption, remains a significant challenge. challenge. This study investigates if MCPyV sT oncoprotein, together with HPV-18 oncoproteins, affects the transcription of key genes, influencing cell proliferation and cisplatin resistance in CxCa. Methods: The sT gene was cloned into the pCMV6 vector and introduced into E. coli DH5α cells. HeLa cells were transfected with pCMV6-sT using Lipofectamine 3000. Transfection efficiency was assessed using fluorescence microscopy and flow cytometry. Protein expression was analyzed by SDS-PAGE and Western blotting. Cytotoxicity was measured with the MTT assay, gene expression was analyzed by RT-qPCR, Ki-67 staining was performed on cell blocks, and cisplatin-induced effects on cell proliferation and apoptosis were examined. Results: Cytotoxicity assays showed a significant increase in cell viability at 0.2 μg of sT plasmid after 72 hours (13.76%, P < 0.05). MCPyV sT expression significantly upregulated the mRNA levels of E1 (4.22-fold), E6/E7 (3.80-fold), and MMP1 (6-fold) (P < 0.001). Increased Ki-67 positivity, indicated enhanced cell proliferation. Additionally, sT expression reduced cisplatin-induced apoptosis, with fewer apoptotic cells observed in the sT + cisplatin group compared to the cisplatin-only group (25.9% vs. 38.3%, P < 0.05). Conclusion: The simultaneous presence of MCPyV sT and HPV oncoproteins enhances resistance to cisplatin-induced apoptosis in cervical cancer cells, necessitating further investigation into viral oncoprotein interactions to overcome therapeutic resistance.

This publication has 69 references indexed in Scilit: