Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gene therapy using recombinant adeno-associated virus vectors (rAAV) is generally considered safe. During the course of a study designed to determine the long-term efficacy of rAAV-mediated gene therapy initiated in newborn mice with the lysosomal storage disease, mucopolysaccharidosis type VII (MPSVII), a significant incidence of hepatocellular carcinomas and angiosarcomas was discovered. A hepatocellular carcinoma was first detected in a 35-week-old mouse and by 72 weeks of age, three out of five rAAV-treated MPSVII mice had similar lesions. These types of tumors had not been seen previously in long-term studies of MPSVII mice using recombinant enzyme or bone marrow transplantation. In an attempt to ascertain whether mouse strain or GUSB expression confers susceptibility to tumor formation, we histopathologically examined untreated normal mice of the same strain, untreated MPSVII mice, and normal mice overexpressing human GUSB for the presence of tumors and increased hepatocyte replication. The results of these studies do not indicate that MPSVII mice or mice overexpressing human GUSB are susceptible to tumor formation; however, the number of animals examined is too small to draw definitive conclusions. Results from quantitative PCR performed on the tumor samples suggest that the tumors are probably not caused by an insertional mutagenesis event followed by the clonal expansion of a transformed cell. In a separate study, a relatively large group of mice injected with varying doses and types of rAAV vectors had no evidence of hepatic or vascular tumors. Although the mechanism of tumor formation is currently unknown, the tumorigenic potential of rAAV vectors must be rigorously determined in long-term in vivo studies.
 ...
PMID:Observed incidence of tumorigenesis in long-term rodent studies of rAAV vectors. 1157 65

Adeno-associated viruses (AAV) are promising gene therapy vectors that have little or no acute toxicity. We show that normal mice and mice with mucopolysaccharidosis VII (MPS VII) develop hepatocellular carcinoma (HCC) after neonatal injection of an AAV vector expressing b-glucuronidase. AAV proviruses were isolated from four tumors and were all located within a 6-kilobase region of chromosome 12. This locus encodes several imprinted transcripts, small nucleolar RNAs (snoRNAs), and microRNAs. Transcripts from adjacent genes encoding snoRNAs and microRNAs were overexpressed in tumors. Our findings implicate this locus in the development of HCC and raise concerns over the clinical use of AAV vectors.
 ...
PMID:AAV vector integration sites in mouse hepatocellular carcinoma. 1765 16

Recombinant adeno-associated viruses (rAAVs) have been tested in humans and other large mammals without adverse events. However, one study of mucopolysaccharidosis VII correction in mice showed repeated integration of rAAV in cells from hepatocellular carcinoma (HCC) in the Dlk1-Dio3 locus, suggesting possible insertional mutagenesis. In contrast, another study found no association of rAAV integration with HCC, raising questions about the generality of associations between liver transformation and integration at Dlk1-Dio3. Here we report that in rAAV-treated ornithine transcarbamylase (Otc)-deficient mice, four examples of integration sites in Dlk1-Dio3 could be detected in specimens from liver nodule/tumors, confirming previous studies of rAAV integration in the Dlk1-Dio3 locus in the setting of another murine model of metabolic disease. In one case, the integrated vector was verified to be present at about one copy per cell, consistent with clonal expansion. Another verified integration site in liver nodule/tumor tissue near the Tax1bp1 gene was also detected at about one copy per cell. The Dlk1-Dio3 region has also been implicated in human HCC and so warrants careful monitoring in ongoing human clinical trials with rAAV vectors.
 ...
PMID:Recombinant adeno-associated virus integration sites in murine liver after ornithine transcarbamylase gene correction. 2362 41