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Updated: Nov 25, 2025
Lentiviral Vector-mediated Gene Therapy of Hepatocytes Ex Vivo for Autologous Transplantation in Swine
Published on: November 4, 2018
Targeted suicide gene therapy for liver cancer based on ribozyme-mediated RNA replacement through
Seung Ryul Han1, Chang Ho Lee2, Ji Young Im2
1R&D Center, Rznomics, Inc., Seongnam 13486, Republic of Korea.
Abstract:
Hepatocellular carcinoma (HCC) has high fatality rate and limited therapeutic options. Here, we propose a new anti-HCC approach with high cancer-selectivity and efficient anticancer effects, based on adenovirus-mediated Tetrahymena group I trans-splicing ribozymes specifically inducing targeted suicide gene activity through HCC-specific replacement of telomerase reverse transcriptase (TERT) RNA. To confer potent anti-HCC effects and minimize hepatotoxicity, we constructed post-transcriptionally enhanced ribozyme constructs coupled with splicing donor and acceptor site and woodchuck hepatitis virus post-transcriptional regulatory element under the control of microRNA-122a (miR-122a). Adenovirus encoding post-transcriptionally enhanced ribozyme improved trans-splicing reaction and decreased human TERT (hTERT) RNA level, efficiently and selectively retarding hTERT-positive liver cancers. Adenovirus encoding miR-122a-regulated ribozyme caused selective liver cancer cytotoxicity, the efficiency of which depended on ribozyme expression level relative to miR-122a level. Systemic administration of adenovirus encoding the post-transcriptionally enhanced and miR-regulated ribozyme caused efficient anti-cancer effects at a single dose of low titers and least hepatotoxicity in intrahepatic multifocal HCC mouse xenografts. Minimal liver toxicity, tissue distribution, and clearance pattern of the recombinant adenovirus were observed in normal animals administered either systemically or via the hepatic artery. Post-transcriptionally regulated RNA replacement strategy mediated by a cancer-specific ribozyme provides a clinically relevant, safe, and efficient strategy for HCC treatment.
Insights
A novel adenovirus-mediated strategy uses Tetrahymena group I trans-splicing ribozymes to target hepatocellular carcinoma (HCC) by replacing telomerase reverse transcriptase (TERT) RNA. This approach demonstrates potent anti-cancer effects with minimal liver toxicity in preclinical models.
Area of Science:
- Oncology
- Molecular Biology
- Gene Therapy
Background:
- Hepatocellular carcinoma (HCC) presents a significant global health challenge with high mortality and limited effective treatments.
- Targeting cancer-specific molecular pathways is crucial for developing effective and selective therapies.
- Telomerase reverse transcriptase (TERT) is frequently overexpressed in HCC, making it a promising therapeutic target.
Purpose of the Study:
- To develop and evaluate a novel adenovirus-mediated gene therapy approach for hepatocellular carcinoma (HCC).
- To engineer Tetrahymena group I trans-splicing ribozymes for targeted RNA replacement of telomerase reverse transcriptase (TERT) in HCC cells.
- To enhance ribozyme activity and liver-specific targeting using post-transcriptional regulation and microRNA control.
Main Methods:
- Construction of adenovirus vectors encoding engineered ribozymes with enhanced trans-splicing activity and microRNA-122a (miR-122a) regulation.
- Evaluation of ribozyme-mediated reduction of human TERT (hTERT) RNA levels in HCC cells.
- Assessment of anti-cancer efficacy and hepatotoxicity in intrahepatic multifocal HCC mouse xenografts following systemic administration of the engineered adenovirus.
Main Results:
- Adenovirus-mediated ribozyme expression effectively reduced hTERT RNA levels, leading to selective retardation of hTERT-positive liver cancers.
- miR-122a-regulated ribozyme demonstrated selective liver cancer cytotoxicity, with efficiency dependent on expression levels.
- Systemic administration of the optimized adenovirus achieved significant anti-cancer effects at low doses with minimal observed hepatotoxicity in mouse models.
Conclusions:
- Post-transcriptionally regulated RNA replacement using cancer-specific ribozymes offers a safe and effective strategy for HCC treatment.
- Adenovirus-mediated delivery of engineered ribozymes shows promise for targeted HCC therapy with reduced systemic toxicity.
- This approach represents a clinically relevant advancement in the development of targeted therapies for liver cancer.
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