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Updated: Apr 18, 2026
Study of Viral Vectors in a Three-dimensional Liver Model Repopulated with the Human Hepatocellular Carcinoma Cell Line HepG2
Published on: October 24, 2016
Vector design influences hepatic genotoxicity after adeno-associated virus gene therapy
Abstract:
The use of adeno-associated virus (AAV) as a gene therapy vector has been approved recently for clinical use and has demonstrated efficacy in a growing number of clinical trials. However, the safety of AAV as a vector has been challenged by a single study that documented hepatocellular carcinoma (HCC) after AAV gene delivery in mice. Most studies have not noted genotoxicity following AAV-mediated gene delivery; therefore, the possibility that there is an association between AAV and HCC is controversial. Here, we performed a comprehensive study of HCC in a large number of mice following therapeutic AAV gene delivery. Using a sensitive high-throughput integration site-capture technique and global expressional analysis, we found that AAV integration into the RNA imprinted and accumulated in nucleus (Rian) locus, and the resulting overexpression of proximal microRNAs and retrotransposon-like 1 (Rtl1) were associated with HCC. In addition, we demonstrated that the AAV vector dose, enhancer/promoter selection, and the timing of gene delivery are all critical factors for determining HCC incidence after AAV gene delivery. Together, our results define aspects of AAV-mediated gene therapy that influence genotoxicity and suggest that these features should be considered for design of both safer AAV vectors and gene therapy studies.
Insights
Adeno-associated virus (AAV) gene therapy can cause hepatocellular carcinoma (HCC) in mice by integrating into the Rian locus. Optimizing AAV vector design and delivery is crucial for safer gene therapies.
Area of Science:
- Gene Therapy
- Oncology
- Molecular Biology
Background:
- Adeno-associated virus (AAV) is a promising gene therapy vector with recent clinical approvals.
- Concerns regarding AAV safety have arisen due to a study linking it to hepatocellular carcinoma (HCC) in mice, though this association remains controversial.
Purpose of the Study:
- To comprehensively investigate the potential association between AAV gene delivery and HCC development in a large mouse cohort.
- To identify the molecular mechanisms and critical factors influencing genotoxicity and HCC incidence following AAV gene therapy.
Main Methods:
- Utilized a high-throughput integration site-capture technique to analyze AAV vector integration patterns.
- Performed global expressional analysis to assess changes in gene and microRNA expression.
- Investigated the impact of AAV vector dose, enhancer/promoter selection, and gene delivery timing on HCC incidence.
Main Results:
- AAV integration was found to occur preferentially at the RNA imprinted and accumulated in nucleus (Rian) locus.
- Integration led to overexpression of proximal microRNAs and retrotransposon-like 1 (Rtl1), which were associated with HCC.
- AAV vector dose, promoter/enhancer choice, and delivery timing significantly influenced HCC occurrence.
Conclusions:
- AAV integration into the Rian locus and subsequent overexpression of specific microRNAs and Rtl1 are linked to HCC development.
- Key factors such as vector dose, promoter selection, and delivery timing critically affect AAV genotoxicity and HCC risk.
- Findings provide crucial insights for designing safer AAV vectors and optimizing gene therapy protocols to mitigate genotoxicity.
