We devised a novel insertional mutagenesis approach based on lentiviral vectors to induce hepatocellular carcinoma in three mouse models and identified four novel cancer initiating genes. Two genes are the well characterized Braf and Sos1, while the other two are Fign, encoding an AAA ATPase whose functions are poorly understood, and the paternally expressed gene Rtl1 within the complex Dlk1-Dio3 imprinted region recently involved in stemness. Interestingly, Fign and Braf regulate the expression of the maternal genes of the Dlk1-Dio3 imprinted region, suggesting that both maternally and paternally expressed genes of this region play a role in hepatocarcinogenesis. Moreover, all the genes identified are upregulated and/or amplified/deleted in human hepatocellular carcinoma and play a relevant role in human hepatocarcinogenesis, as their expression levels and/or transcriptional signatures induced by their deregulation predict a different clinical outcome in hepatocellular carcinoma patients.
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Specimen part, Time
View SamplesWe devised a novel insertional mutagenesis approach based on lentiviral vectors to induce hepatocellular carcinoma in three mouse models and identified four novel cancer initiating genes. Two genes are the well characterized Braf and Sos1, while the other two are Fign, encoding an AAA ATPase whose functions are poorly understood, and the complex Dlk1-Dio3 imprinted region which has been recently implicated in cancer and stemness. Activation of Fign or Braf and upregulation of the Dlk1-Dio3 imprinted region are functionally interconnected and may altogether control cell transformation, stemness and energy metabolism. Moreover, all the genes identified play a relevant role in human hepatocarcinogenesis as their expression levels and/or transcriptional signatures induced by their deregulation predict a different clinical outcome in hepatocellular carcinoma patients. These series consists of mRNA expression microarray data (The GeneChip Mouse Gene 1.0 ST Array, Affymetrix) from 8 non-tumoral liver and 21 hepatocellular carcinoma induced by insertional mutagenesis.
Lentiviral vector-based insertional mutagenesis identifies genes associated with liver cancer.
Specimen part
View SamplesGene transfer into HSCs by gammaretroviral vectors (RV) is an effective treatment for inherited blood disorders, although potentially limited by the risk of insertional mutagenesis. We evaluated the genomic impact of RV integration in T-lymphocytes from adenosine deaminase (ADA)-Severe combined immunodeficiency (SCID) patients 10 to 30 months after infusion of autologous, genetically-corrected CD34+ cells. Expression profiling on ex vivo T-cell bulk population revealed no difference with respect to healthy controls. To assess the effect of vector integration on gene expression at the single cell level, primary T-cell clones were isolated from two patients. T-cell clones harboured either one or two vector copies per cell and displayed partial to full correction of ADA expression, purine metabolism and TCR-driven functions. Analysis of retroviral integration sites (RIS) indicated a high diversity in T-cell origin, consistent with the polyclonal TCR-Vbeta repertoire. Quantitative transcript analysis of 120 genes within a 200kb-window around RIS showed modest (2.8- to 5.2-fold) disregulation of 5.8% genes in 18.6% of the T-cell clones compared to controls. Nonetheless, affected clones maintained a stable phenotype and normal functions in vitro. These results confirm that RV-mediated gene transfer for ADA-SCID is safe, and provide crucial information for the development of future gene therapy protocols.
Integration of retroviral vectors induces minor changes in the transcriptional activity of T cells from ADA-SCID patients treated with gene therapy.
Specimen part
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