Oncolytic Adenovirus H101 Synergizes with Radiation in Cervical Cancer Cells

A major challenge in cervical cancer radiotherapy is tailoring the radiation doses efficiently to eliminate malignant cells and reduce the side effects in normal tissues. Oncolytic adenovirus drug H101 was recently tested and approved as a topical adjuvant treatment for several malignancies.

This study aimed to evaluate the potential neoadjuvant radiotherapy benefits of H101 by testing the inhibitory function of H101 in combination with radiation in different cervical cancer cells.

Human cervical cancer cell lines C33a, SiHa, CaSki, and HeLa were treated with varying concentrations of H101 alone or in combination with radiation (2 Gy or 4 Gy). Cell viability and apoptosis were measured at the indicated time intervals. HPV16 E6 and cellular p53 mRNA expression alteration was measured by qRT-PCR. In situ RNA scope was used to determine HPV E6 status. P53 protein alterations were detected by Western blot.

Cell viability and apoptosis assays revealed that the combination of a high dose of H101 (MOI=1000, 10000) with radiation yielded a synergistic anticancer effect in all tested cervical cancer cell lines (P<0.05), with the greatest effect achieved in HPV-negative C33a cells (P<0.05). Low-HPV16-viral-load SiHa cells were more sensitive to the combination therapy than high-HPV16- viral-load CaSki cells (P<0.05). The combined treatment reduced HPV16 E6 expression and increased cellular P53 levels compared to those observed with radiation alone in SiHa and CaSki cells (P<0.05).

Oncolytic adenovirus H101 effectively enhances the antitumor efficacy of radiation in cervical cancer cells and may serve as a novel combination therapy for cervical cancer.