Our laboratory is focused on the identification and characterization of genes that participate in cancer biology through the use of forward genetics. We employ multiple transposon-based systems to perform insertional mutagenesis in cell culture and in mice for the purpose of identifying novel genes that contribute to tumor cell initiation, progression, and metastasis. These approaches facilitate the discovery of genes and pathways that functionally contribute to tumorigenesis and provide a complementary approach to large-scale cancer genome sequencing studies.
Our current research focuses on the following areas:
1) Application of LINE-1 (L1) retrotransposon and Sleeping Beauty DNA transposon gene trap mouse models to identify genes that participate in the pathogenesis of cancer.
We have generated a tetracycline (tet)-regulated LINE-1 mouse model harboring a gene trap cassette (tet-ORFeus) which we are currently breeding to multiple well-established mouse models of cancer. Progeny of these mice will be screened for early-developing tumors and transposon insertions will be mapped. As a complementary approach, we are also utilizing the Sleeping Beauty DNA transposon system to identify genes that accelerate tumorigenesis in mice.
2) Functional validation of the contribution of genes identified on our forward genetic screens to tumor initiation and progression.
The relevance of the common insertion sites identified in these screens are assessed by determining whether the identified genes exhibit abnormalities in human tumor samples. Candidate gene loci are screened for expression changes, copy-number alterations, epigenetic modifications, and mutations. Gain- and loss-of-function experiments in model cell lines are performed to directly demonstrate a functional role for candidate genes in tumorigenesis.
3) Development of an ex vivo transposon mutagenesis system to facilitate the rapid identification of cancer susceptibility genes.
This approach involves performing mutagenesis on cells growing in culture with our transposon gene trap constructs. These cells are then implanted in animals and insertion sites associated with the development and progression of different tumor types are recovered. This strategy provides a complementary approach to our transgenic mouse systems, and is adaptable to many cellular phenotypes.