Using a Human Papillomavirus Model to Study DNA Replication and Repair of Wild Type and Damaged DNA Templates in Mammalian Cells

Recombinant adenoviruses expressing HPV16/18 E7 upregulate the HDAC6 and DNMT3B genes in C33A cells

OBJECTIVE

High-risk human papillomavirus (HPV) is a carcinogenic virus associated with nearly all cases of cervical cancer, as well as an increasing number of anal and oral cancers. The two carcinogenic proteins of HPV, E6 and E7, can immortalize keratinocytes and are essential for HPV-related cellular transformation. Currently, the global regulatory effects of these oncogenic proteins on the host proteome are not fully understood, and further exploration of the functions and carcinogenic mechanisms of E6 and E7 proteins is needed.

METHODS

We used a previously established platform in our laboratory for constructing recombinant adenoviral plasmids expressing the HPV16 E7 gene to further construct recombinant virus particles expressing HPV16/18 E6, E7, and both E6 and E7 genes. These recombinant viruses were used to infect C33A cells to achieve sustained expression of the HPV16/18 E6/E7 genes. Subsequently, total RNA was extracted and RNA-Seq technology was employed for transcriptome sequencing to identify differentially expressed genes associated with HPV infection in cervical cancer.

RESULTS

RNA-Seq analysis revealed that overexpression of the HPV16/18 E6/E7 genes upregulated GP6, CD36, HDAC6, ESPL1, and DNMT3B among the differentially expressed genes (DEGs) associated with cervical cancer. Spearman correlation analysis revealed a statistically significant correlation between the HDAC6 and DNMT3B genes and key pathways, including DNA replication, tumor proliferation signature, G2M checkpoint, p53 pathways, and PI3K/AKT/mTOR signaling pathways. Further, qRT-PCR and Western blot analyses indicated that both HPV16/18 E7 can upregulate the expression of HDAC6 and DNMT3B, genes associated with HPV infection-related cervical cancer.

CONCLUSION

The successful expression of HPV16/18 E6/E7 in cells indicates that the recombinant viruses retain the replication and infection capabilities of Ad4. Furthermore, the recombinant viruses expressing HPV16/18 E7 can upregulate the HDAC6 and DNMT3B genes involved in cervical cancer pathways, thereby influencing the cell cycle. Additionally, HDAC6 and DNMT3B are emerging as important therapeutic targets for cancer. This study lays the foundation for further exploration of the oncogenic mechanisms of HPV E6/E7 and may provide new directions for the treatment of HPV-related cancers.

Recognition of DNA Lesions

The average human cell suffers from approximately 10⁴-10⁵ DNA lesions per day [...].

DNA Damage Repair-Related Genes Signature for Immune Infiltration and Outcome in Cervical Cancer

Background: The mechanism of DNA damage repair plays an important role in many solid tumors represented by cervical cancer.

Purpose: The purpose of this study was to explore the effect of DNA damage repair-related genes on immune function of patients with cervical cancer, and to establish and evaluate a prognosis model based on DNA damage repair-related genes.

Methods: In the study, we analyzed the genes related to DNA damage and repair, and obtained two subtypes (F1 and F2). We selected two groups of samples for different selection, and studied which pathways were enriched expression. For different subtypes, the immune score was explored to explain immune infiltration. We got the key genes through screening, and established the prognosis model through the key genes. These 11 key genes were correlated with the expression of common Clusters of Differentiation (CD) genes in order to explore the effects of these genes on immunity.

Results: Through the Least absolute shrinkage and selection operator (LASSO) method, we screened 11 genes from 232 candidate genes as the key genes for the prognosis score. Through the Kaplan-Meier method, four genes (HAP1, MCM5, RNASEH2A, CETN2) with significant prognostic significance were screened into the final model, forming a Nomogram with C-index of 0.716 (0.649–1.0).

Conclusion: In cervical cancer, DNA damage repair related genes and immune cell infection characteristics have certain association, and DNA damage repair related genes and immune cell infection characteristics can effectively predict the prognosis.