E6AP gene suppression and characterization with in vitro selected hammerhead ribozymes

Area of Science:

• Molecular Biology
• Cancer Research
• Virology

Background:

• E6AP (E6-associated protein) is an E3 ubiquitin-protein ligase crucial for human papillomavirus (HPV) E6-mediated p53 degradation.
• E6AP targets multiple protein substrates for ubiquitination, highlighting its broad cellular role.
• Understanding E6AP's precise function requires effective gene inactivation methods.

Purpose of the Study:

• To develop and validate a ribozyme-based approach for inactivating the E6AP gene.
• To investigate the cellular consequences of reduced E6AP expression, particularly concerning apoptosis.
• To assess the therapeutic potential of targeting E6AP in HPV-positive cancer cells.

Main Methods:

• A library of hammerhead ribozymes was screened against the E6AP transcript to identify cleavage sites.
• Ligation-anchored PCR was employed to detect ribozyme-mediated cleavage products.
• Selected ribozymes were characterized both in vitro and in vivo to confirm efficacy.

Main Results:

• Ribozyme-mediated reduction of E6AP expression was successfully achieved.
• Suppression of E6AP significantly enhanced the apoptotic response of HeLa cells to mitomycin C.
• This potentiation of apoptosis occurred specifically in HPV-positive cells.

Conclusions:

• E6AP gene inactivation via ribozymes is a viable strategy for modulating cellular processes.
• Reduced E6AP expression sensitizes HPV-positive cells to cytotoxic drug-induced DNA damage and apoptosis.
• E6AP represents a promising drug target for enhancing cancer therapy efficacy in HPV-associated cancers.