Oncolytic human adenovirus 5 (H101) modulates cell cycle progression in HPV16-positive tumors

Cervical cancer remains a major threat to women's health. Cervical intraepithelial neoplasia (CIN) is a recognized precursor of cervical cancer. Treating CIN may prevent its progression to invasive carcinoma. H101, a recombinant human adenovirus type 5, is a potential anticancer agent and has demonstrated therapeutic effects in gynecological diseases; however, its efficacy and mechanism of action remain unclear. This study aimed to systematically investigate the antitumor effects of H101 in a CIN model. In vitro experiments were conducted using p53-knockdown H8 cells. Cell proliferation, apoptosis, cell cycle distribution, and cell invasion ability were assessed using the CCK-8 assay, flow cytometry, and Transwell assay, respectively. The expression levels of related genes and proteins were detected using qPCR and western blotting, respectively. An in vivo tumor-bearing mouse model was established to validate antitumor efficacy. H101 significantly inhibited cell proliferation, induced apoptosis, arrested the cell cycle at the G1/S phase, and reduced cell invasion. At the molecular level, H101 downregulated HPV16 E6/E7 expression, thereby activating the p53-p21 signaling axis and inhibiting CDK1 phosphorylation. Although p53 knockdown attenuated the efficacy of H101, it did not completely abolish its anti-cancer activity, suggesting the presence of a p53-independent pathway. In vivo experiments further confirmed the significant antitumor effects and the favorable safety profile of H101. These findings suggest that the antitumor effects of H101 are associated with the downregulation of HPV16 E6/E7 and the activation of the p53-p21 pathway, involving both p53-dependent and p53-independent mechanisms.