Abstract 3779: Evaluation of anti-cancer efficacy of lipid nanoparticles containing siRNA against HPV16 E6 and E7 combined with cisplatin in xenograft model of cervical cancer
Authors: Kang Sung Wan , Lee Shin-Wha , Lee Ji-young , Kang Ok Ju , Kim Hyejeong , Kim Yisak , Kim Yong-Man 
Published: April 2023

Background: High-risk human papillomavirus (HPV) type 16 is the major etiological agent found in more than 60% of patients with cervical cancer and associated with cancer development and progression. Persistent expression HPV E6 and E7 oncoproteins are essential for the initiation and maintenance of cervical cancer. The therapeutic approaches targeting HPV E6 and E7 have been proved to be highly efficient in killing malignant cells. The suppression of HPV 16 E6/E7 expression by the short interfering RNA (siRNA) was more effective in combination therapy with cisplatin (CDDP) for cervical cancer. ENB101-LNP is an ionizable lipid nanoparticles (LNPs) encapsulating siRNA against E6/E7 of HPV 16 for delivery to the tumor cells.

Methods: To investigate the anticancer efficacy and mechanism of ENB101-LNP combined with cisplatin in cervical cancer; the xenograft model was generated by the injection of CaSki cells subcutaneously into BALB/c nude mice. Mice were randomly divided into six groups: 1) blank control; 2) 1mg/kg ENB101-LNP; 3) 3mg/kg ENB101-LNP; 4) CDDP; 5) 1mg/kg ENB101-LNP-CDDP; 6) 3mg/kg ENB101-LNP-CDDP. ENB101-LNP was treated with intravenous injection three times weekly for 3 weeks and CDDP was treated with IP injection once a week for 3 weeks. Tumor growth curves were plotted to calculate the tumor inhibition rate. Mice were sacrificed one week after the last treatment and the tumor tissues were investigated using histopathology, immunohistochemical staining and western blotting.

Results: Compared with the control and the other treatment groups, the tumor growth was significantly inhibited (P &lt; 0.05). The tumor inhibition rate was 29.7% in 1mg/kg ENB101-LNP group, 29.6% in 3mg/kg ENB101-LNP group, 34.0% in CDDP group, 47.0% in 1mg/kg ENB101-LNP-CDDP group. At the dose of 3mg ENB101-LNP/kg combined with CDDP exhibited superior antitumor efficacy, the tumor inhibition rate was 68.8%. The successful ENB101-LNP mediated knockdown (with up to 80%) of HPV16 E6/E7 in tumors of both 1mg/kg and 3mg/kg groups was confirmed by RT-PCR. The ENB101-LNP increased p53 and p21 expression in tumors compared to control and CDDP alone groups and combination treatment with CDDP showed decreased expression of PD-L1 expression compared to CDDP alone group. The treatment of ENB101-LNP and combination with CDDP showed significant increase in apoptotic cells compared to control and single-agent groups respectively.

Conclusions: The ENB101-LNP inhibiting E6 and E7 of HPV 16 in combination with CDDP showed promising anticancer activity in the cervical cancer cells xenograft mouse model.

Citation Format: Sung Wan Kang, Shin-Wha Lee, Ji-young Lee, Ok Ju Kang, Hyejeong Kim, Yisak Kim, Yong-Man Kim. Evaluation of anti-cancer efficacy of lipid nanoparticles containing siRNA against HPV16 E6 and E7 combined with cisplatin in xenograft model of cervical cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3779.