Supplementary Figure Legends 1-3 from Insertional Mutagenesis in Mice Deficient for <i>p15<sup>Ink4b</sup>, p16<sup>Ink4a</sup>, p21<sup>Cip1</sup></i>, and <i>p27<sup>Kip1</sup></i> Reveals Cancer Gene Interactions and Correlations with Tumor Phenotypes
Supplementary Figure Legends 1-3 from Insertional Mutagenesis in Mice Deficient for <i>p15<sup>Ink4b</sup>, p16<sup>Ink4a</sup>, p21<sup>Cip1</sup></i>, and <i>p27<sup>Kip1</sup></i> Reveals Cancer Gene Interactions and Correlations with Tumor Phenotypes
Supplementary Table 1 from Insertional Mutagenesis in Mice Deficient for <i>p15<sup>Ink4b</sup>, p16<sup>Ink4a</sup>, p21<sup>Cip1</sup></i>, and <i>p27<sup>Kip1</sup></i> Reveals Cancer Gene Interactions and Correlations with Tumor Phenotypes
<div>Abstract<p>Cancer immunotherapy based on vaccination with defined tumor antigens has not yet shown strong clinical efficacy, despite promising results in preclinical models. This discrepancy might result from the fact that available preclinical models rely on transplantable tumors, which do not recapitulate the long-term host-tumor interplay that occurs in patients during progressive tumor development and results in tumor tolerance. To create a faithful preclinical model for cancer immunotherapy, we generated a transgenic mouse strain developing autologous melanomas expressing a defined tumor antigen recognized by T cells. We chose the antigen encoded by <i>P1A</i>, a well-characterized murine cancer germ line gene. To transform melanocytes, we aimed at simultaneously activating the Ras pathway and inactivating tumor suppressor Ink4a/Arf, thereby reproducing two genetic events frequently observed in human melanoma. The melanomas are induced by s.c. injection of 4-OH-tamoxifen (OHT). By activating a CreER recombinase expressed from a melanocyte-specific promoter, this treatment induces the loss of the conditional <i>Ink4a/Arf</i> gene in melanocytes. Because the <i>CreER</i> gene itself is also flanked by loxP sites, the activation of CreER also induces the deletion of its own coding sequence and thereby allows melanocyte-specific expression of genes <i>H-ras</i> and <i>P1A</i>, which are located downstream on the same transgene. All melanomas induced in those mice with OHT show activation of the Ras pathway and deletion of gene <i>Ink4a/Arf</i>. In addition, these melanomas express <i>P1A</i> and are recognized by P1A-specific T lymphocytes. This model will allow to characterize the interactions between the immune system and naturally occurring tumors and thereby to optimize immunotherapy approaches targeting a defined tumor antigen. (Cancer Res 2006; 66(6): 3278-86)</p></div>
Abstract Cdkn2ab knockout mice, generated from 129P2 ES cells develop skin carcinomas. Here we show that the incidence of these carcinomas drops gradually in the course of backcrossing to the FVB/N background. Microsatellite analyses indicate that this cancer phenotype is linked to a 20 Mb region of 129P2 chromosome 15 harboring the Wnt7b gene, which is preferentially expressed from the 129P2 allele in skin carcinomas and derived cell lines. ChIPseq analysis shows enrichment of H3K27-Ac, a mark for active enhancers, in the 5’ region of the Wnt7b 129P2 gene. The Wnt7b 129P2 allele appears sufficient to cause in vitro transformation of Cdkn2ab -deficient cell lines primarily through CDK6 activation. These results point to a critical role of the Cdkn2ab locus in keeping the oncogenic potential of physiological levels of WNT signaling in check and illustrate that GWAS-based searches for cancer predisposing allelic variants can be enhanced by including defined somatically acquired lesions as an additional input.
Abstract Human cancers modeled in Genetically Engineered Mouse Models ( GEMM s) can provide important mechanistic insights into the molecular basis of tumor development and enable testing of new intervention strategies. The inherent complexity of these models, with often multiple modified tumor suppressor genes and oncogenes, has hampered their use as preclinical models for validating cancer genes and drug targets. In our newly developed approach for the fast generation of tumor cohorts we have overcome this obstacle, as exemplified for three GEMM s; two lung cancer models and one mesothelioma model. Three elements are central for this system; (i) The efficient derivation of authentic Embryonic Stem Cells ( ESC s) from established GEMM s, (ii) the routine introduction of transgenes of choice in these GEMM ‐ ESC s by F lp recombinase‐mediated integration and (iii) the direct use of the chimeric animals in tumor cohorts. By applying stringent quality controls, the GEMM ‐ ESC approach proofs to be a reliable and effective method to speed up cancer gene assessment and target validation. As proof‐of‐principle, we demonstrate that MycL1 is a key driver gene in Small Cell Lung Cancer.
