Abstract 668: Induction of mammary carcinoma in tetracycline-inducible cMET(T1010I) transgenic mice

Abstract

Abstract Gene amplification and mutations of cMET have been reported in a wide variety of tumors, including colorectal, lung, renal, liver, thyroid, and breast cancer. cMET(T1010I) mutation occurred in 5.2% out of 148 sibling pairs diagnosed with colorectal cancer in one study. This germline mutation occurs in about 1% of breast cancer patients, but its frequency increases to 2% in metastatic breast cancer. Furthermore, 16% of breast cancer cases with PI3KCA mutations have co-mutations of the cMET oncogene. To determine the functional consequences of this germline mutation and elucidate the molecular mechanisms of tumorigenesis induced by its oncogenic mutant protein, we developed a transgenic mouse model expressing human cMET(T1010I) under the control of a Tet-responsive promoter. MMTV promoter - directed expression of reverse tetracycline-controlled transactivator (rtTA) turns on the expression of the cMET(T1010I) transgene in murine mammary glands upon tetracycline administration. Thirty percent of these mice developed early onset mammary carcinoma within 5 months of transgene induction. This contrasts with previous reports of mammary tumor development in MMTV-cMET transgenic mice after more than a year. This strong phenotype is not the result of a random insertional effect of the transgene as no mammary tumors developed in the 29 transgene positive mice without mammary-specific expression of rtTA over a year in our study. Molecular characterization of these tumors is currently underway and the results may reveal mechanisms of tumorigenesis and novel therapeutic targets for patients harboring this mutation. In conclusion, we showed for the first time that the cMET(T1010I) mutation can trigger rapid breast tumorigenicity. By using organ-specific expression of rtTA to direct the expression of cMET(T1010I) in the organ of interest, our transgenic model may be used to understand the impact of cMET(T1010I) on many other cancer types such as colorectal, lung, renal, thyroid, and liver cancer. Citation Format: Chuanwei Yang, Ana M. Gonzalez, Naoto T. Ueno, Shuying Liu, Jinsong Zhang, Gordon B. Mills, John Mendelsohn, Prahlad Ram. Induction of mammary carcinoma in tetracycline-inducible cMET(T1010I) transgenic mice. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 668.