Recombinant adenovirus encoding H-ras ribozyme induces apoptosis in laryngeal cancer cells through caspase- and...

Area of Science:

• Molecular Biology
• Gene Therapy
• Oncology

Background:

• A previously designed ribozyme targets the H-ras oncogene at codon 12.
• Ribozymes possess antisense and site-specific ribonuclease capabilities.
• Laryngeal cancer cells (HEp-2) were utilized to investigate H-ras ribozyme efficacy.

Purpose of the Study:

• To evaluate the cytotoxic gene therapy potential of an H-ras ribozyme delivered via adenoviral vector in laryngeal cancer cells.
• To elucidate the apoptosis-mediated mechanisms underlying H-ras ribozyme-induced tumor growth inhibition.

Main Methods:

• Adenoviral vector-mediated delivery of H-ras ribozyme into HEp-2 cells.
• Assessment of H-ras gene expression downregulation.
• Analysis of apoptosis pathways, including caspase activation, mitochondrial events (superoxide anion production, cytochrome c release, mitochondrial transmembrane potential), and Bcl-2 influence.

Main Results:

• The H-ras ribozyme effectively downregulated H-ras gene expression in HEp-2 cells, exhibiting antisense activity.
• Recombinant adenovirus encoding the H-ras ribozyme demonstrated broad cytotoxic gene therapy effects on laryngeal cancer cells.
• Tumor growth inhibition was mediated by apoptosis, involving caspase- and mitochondria-dependent pathways, with key caspase activations and mitochondrial events observed at specific time points.

Conclusions:

• The recombinant adenovirus encoding the H-ras ribozyme is a promising cytotoxic gene therapy for laryngeal cancer.
• H-ras ribozyme-induced apoptosis involves both caspase- and mitochondria-mediated pathways.
• While Bcl-2 influences cytochrome c release, it does not prevent H-ras ribozyme-induced apoptosis, suggesting its release may not be the primary driver.