Reduction of NFX1-123 and HPV 16 E6 and E7 Decreased Telomerase and CENP-F in Cervical Cancer Cell Lines

Telomerase activity is a cancer hallmark, and hTERT is the rate-limiting catalytic subunit of telomerase. In human papillomavirus type 16 E6 (16E6)-expressing epithelial cells, NFX1-123 augments and is required for full hTERT expression, leading to a growth advantage. However, no studies have investigated the role of NFX1-123 in telomerase activity regulation in HPV-associated cancers.

We knocked out NFX1-123 in CaSki cells (CaSki KO) and performed single-cell RNA sequencing to determine mRNA alterations affected by reduced NFX1-123.

In CaSki KO cells, there were three cell clusters based on gene expression, each associated with different enriched biological processes. When pooled and compared with control cells, CaSki KO cells had 1661 decreased and 565 increased mRNAs involving RNA regulation, cell cycle and division, chromatin regulation, and carcinogenesis processes and pathways. CENP-F, a cell cycle and chromosome segregation gene increased in cervical cancers, was among 10 genes with the greatest decrease in mRNA expression in CaSki KO cells. CaSki and SiHa cells with either reduced NFX1-123 or knocked down HPV 16 E6 and E7, demonstrated reduced hTERT, CENP-F, and telomerase activity, and when both NFX1-123 and HPV 16 E6 and E7 were decreased, hTERT and telomerase activity fell further. Finally, hTERT and CENP-F were increased in cervical cancer primary tumors and in HPV-positive head and neck cancer primary tumors in the TCGA database.

These findings highlight the shared role that NFX1-123 has with HPV 16 oncogenes in driving and maintaining RNA, cell cycle, and carcinogenesis pathways, and specifically regulating hTERT, telomerase, and CENP-F.