The Application of CRISPR/Cas9 System in Cervical Precancerous Lesions

Abstract Background : The clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system is becoming a promising gene therapy method. Herein, we evaluated the therapeutic effect of CRISPR/Cas9 system in cervical carcinogenesis, especially cervical precancerous lesions. Methods : In cervical cancer/pre-cancer cell lines, we transfected the CRISPR/Cas9, transcription activator–like effector nuclease (TALEN), and zinc finger nuclease (ZFN) plasmids, respectively. We used the cell apoptosis, cell viability, and colony formation assays to examine the efficiency and specificity of inhibition of cell apoptosis and growth between the different gene editing tools. Western blotting was used to estimate the related protein expression. We used xenograft formation assays to examine the ability of inhibition of cell growth in vivo. In the K14-HPV16 transgenic mice model of HPV-driven cervical carcinogenesis, we investigated the therapeutic effect by vaginal administration. Results : Compared to ZFN and TALEN, CRISPR/Cas9 has shown comparable efficiency and specificity of inhibition of cell apoptosis and growth in cervical cancer cell lines, which seem to be more pronounced in the S12 cell line derived from the low-grade cervical lesion. In xenograft formation assays, CRISPR/Cas9 could inhibit tumor formation in vivo and affects the expression of the corresponding protein. In the K14-HPV16 transgenic mice, CRISPR/Cas9 treatment caused mutations of the E7 gene and restored the expression of RB, E2F1, and CDK2, thereby reversing the cervical carcinogenesis phenotype. Conclusion : In this study, we have demonstrated that CRISPR/Cas9 targeting HPV16 E7 could effectively reduce the expression of E7 protein in vitro. Additionally, it could revert the HPV-related cervical carcinogenesis in K14-HPV16 transgenic mice, which has shown great potential in clinical treatment.