TALEN based HPV-E7 editing triggers necrotic cell death in cervical cancer cells.

Human Papillomavirus E7 and E6 oncoproteins have been considered as suitable candidate anti-viral targets since they cause malignant conversion in cervical cancers. Transcription Activator-Like Effector Nucleases (TALENs) are recent editing tools to knockout genes by inducing double stranded breaks at specific sites in the genome. In here, we have designed specific TALENs to target E7 and analyzed their efficiency in inducing cell death in cervical cancer cells. We found that designed TALENs could yield about 10-12% editing activity as observed from T7E1 and nuclease resistance assays. Down-regulation of E7 and E6 was further evident at the transcript as well as proteins levels indicating that the selected TALENs were effective. TALEN-mediated E7 editing led to cell death as ascertained by cell cycle and Annexin V assays. Annexin profiling suggested that cell death could be due to necrosis as observed by upregulation of necrotic markers such as LDH A, Rip-1, and Cyclophilin A. Necrosis appears to be a better therapeutic response as it could further activate pro-inflammatory cytokines to attract immune cells to eliminate HPV-integrated cells and therefore TALEN editing strategy has the potential to be a promising tool as an adjuvant therapy in cervical cancer along with surgery.