Dihydroartemisinin administration improves the effectiveness of 5-aminolevulinic acid-mediated photodynamic therapy for the treatment of high-risk human papillomavirus infection

High-risk human papillomavirus (HR-HPV) infection has been confirmed to be highly related to diseases such as Bowenoid papulosis, cervical cancer, and cervical intraepithelial neoplasia. 5-aminolevulinic acid-mediated PDT (ALA-PDT) has been used in a variety of HR-HPV infection-related diseases. Dihydroartemisinin (DHA) is one of artemisinin derivatives, and has inhibitory effects on a variety of cancer cells. For now, there is no published study focusing on the combination use of ALA-PDT with DHA to improve clinical efficacy of HR-HPV infection-related diseases. So in this study, we will examine the effectiveness of combined treatment of ALA-PDT and DHA for HR-HPV infection as well as its underlying mechanism. The human cervical cancer cell line HeLa (containing whole genome of HR-HPV18) was treated with ALA-PDT or/and DHA, and cell viability, long proliferation, ROS production and apoptosis were evaluated by CCK8, colony-forming assay, immunofluorescence and flow cytometry, respectively. The protein expression of NF-κB-HIF-1α-VEGF pathway and NRF2-HO-1 pathway was examined by western blot. The results showed that DHA could enhance the effect of ALA-PDT on cell viability long proliferation, ROS production and apoptosis in HeLa cells. We also found that DHA inhibited NF-κB-HIF-1α-VEGF pathway which was activated by ALA-PDT. Besides, ALA-PDT combined with DHA activated NRF2-HO-1 pathway. Although the NRF2 - NO-1 pathway as a resistance mechanism remains unresolved, DHA has the potential to enhance the effect of ALA-PDT for HPV infection-related diseases through inhibiting NF-κB - HIF-1α - VEGF pathway.