The effect of mouse strain, sex and carcinogen dose on toxicity and the development of lung dysplasia and squamous cell carcinomas in mice

Original Articles
Laura Riolobos, Ekram A. Gad, Piper M. Treuting, Andrew E. Timms, Elliot A. Hershberg, Lauren R. Corulli, Erin Rodmaker and Mary L. Disis
Description / Abstract: 

In order to translate new treatments to the clinic, it is necessary to use animal models that closely recapitulate human disease.  Lung cancer develops after extended exposure to carcinogens.  It has one of the highest mutation rates of all cancer and is highly heterogenic.  Topical treatment with N-nitrosotris-(2-chloroethyl)urea (NTCU) induces lung squamous cell carcinoma (SCC) with nonsynonymous mutation rates similar to those reported for human non-small cell lung cancer.  However, NTCU induces lung cancer with variable efficacy and toxicity depending on the mouse strain.  A detailed characterization of the NTCU model is needed.  We have compared the effect of three different NTCU doses (20, 30 and 40 mM) in female and male of NIH Swiss, Black Swiss and FVB mice on tumor incidence, survival and toxicity.  The main findings in this study are: (1) NIH Swiss mice present with a higher incidence of SCC and lower mortality compared with Black Swiss and FVB mice; (2) 30 mM NTCU dose induces SCC at the same rate and incidence as the 40 mM dose with lower mortality; (3) female mice present higher grade and incidence of pre-invasive lesions and SCC compared with males; (4) NTCU induced transformation is principally within the respiratory system; and (5) NTCU treatment does not impact the ability to elicit a specific adaptive immune response.  This study provides a reference point for experimental designs to evaluate either preventive or therapeutic treatments for lung SCC, including immunotherapies, before initiating human clinical trials.