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Tumor susceptibility of Rassf1a knockout mice. Cancer Res 2005 Jan 01;65(1):92-8

Date

01/25/2005

Pubmed ID

15665283

Scopus ID

2-s2.0-19944429131   178 Citations

Abstract

The human Ras association domain family 1 (RASSF1) gene is located at 3p21.3 in an area that is believed to harbor at least one important tumor suppressor gene. The two major isoforms of RASSF1, RASSF1A and RASSF1C, are distinguished by alternative NH(2)-terminal exons and the two transcripts initiate in two separate CpG islands. RASSF1A is one of the most frequently inactivated genes described thus far in human solid tumors. Inactivation of RASSF1A most commonly involves methylation of the promoter and CpG island associated with the RASSF1A isoform. In contrast, RASSF1C is almost never inactivated in tumors. Here, we have derived Rassf1a knockout mice in which exon 1-alpha of the Rassf1 gene was deleted, leading to specific loss of Rassf1a but not Rassf1c transcripts. Rassf1a-targeted mice were viable and fertile. Rassf1a(-/-) mice were prone to spontaneous tumorigenesis in advanced age (18-20 months). Whereas only two tumors developed in 48 wild-type mice, six tumors were found in 35 Rassf1a(+/-) mice (P < 0.05) and thirteen tumors were found in 41 Rassf1a(-/-) mice (P < 0.001). The tumors in Rassf1a-targeted mice included lung adenomas, lymphomas, and one breast adenocarcinoma. Rassf1a(-/-) and wild-type mice were treated with two chemical carcinogens, benzo(a)pyrene and urethane, to induce skin tumors and lung tumors, respectively. Rassf1a(-/-) and Rassf1a(+/-) mice showed increased tumor multiplicity and tumor size relative to control animals. The data are consistent with the tumor-suppressive role of Rassf1a, which may explain its frequent epigenetic inactivation in human tumors.

Author List

Tommasi S, Dammann R, Zhang Z, Wang Y, Liu L, Tsark WM, Wilczynski SP, Li J, You M, Pfeifer GP



MESH terms used to index this publication - Major topics in bold

Adenocarcinoma
Animals
Base Sequence
Crosses, Genetic
DNA Primers
Genetic Predisposition to Disease
Genotype
Lung Neoplasms
Lymphoma
Mammary Neoplasms, Animal
Mice
Mice, Inbred C57BL
Mice, Knockout
Reverse Transcriptase Polymerase Chain Reaction
Tumor Suppressor Proteins