Human papillomavirus-mediated expression of complement regulatory proteins in human cervical cancer cells

Objectives: This study aimed to evaluate the expression pattern of complement regulatory proteins (CRPs) CD46, CD59, and CD55 in HPV-positive (HPV⁺) & negative (HPV^-) cervical cancer cell lines in search of a reliable differential biomarker. Study Design: We analysed the expression of CRPs in HPV 16-positive SiHa cell line, HPV 18-positive HeLa cell line, and HPV-negative cell line C33a using RT-qPCR, Western blotting, flow cytometry, and confocal microscopy. Results: We observed a differential expression profile of CRPs in HPV⁺ and HPV^- cervical cancer cell lines. The mRNA level of CD59 & CD55 showed a higher expression pattern in HPV⁺ cells when compared to HPV^- cancer cells. However, flow cytometry-based experiments revealed that CD46 was preferentially expressed more in HPV 16-positive SiHa cells followed by HPV 18-positive HeLa cells when compared to HPV^- C33a cells. Interestingly, confocal microscopy revealed a high level of CD59 expression in Hela cells and SiHa cells but low expression in HPV^- C33a cells. In addition, HPV 18-positive HeLa cells expressed more CD55, which was lower in SiHa cells and very weak in C33a cells. Conclusion: The study demonstrates the differential expression of CRPs in both HPV⁺ and HPV^- cervical cancer cells for the first time, and their potential to serve as an early diagnostic marker for cervical carcinogenesis.