A new mouse model to explore the initiation, progression, and therapy of BRAFV600E-induced lung tumors

Abstract

Mutationally activated BRAFV600E (BRAFVE) is detected in ∼6% of human malignancies and promotes sustained MEK1/2–ERK1/2 pathway activation. We have designed BRafCA mice to express normal BRaf prior to Cre-mediated recombination after which BRafVE is expressed at physiological levels. BRafCA mice infected with an Adenovirus expressing Cre recombinase developed benign lung tumors that only rarely progressed to adenocarcinoma. Moreover, BRafVE-induced lung tumors were prevented by pharmacological inhibition of MEK1/2. BRafVE expression initially induced proliferation that was followed by growth arrest bearing certain hallmarks of senescence. Consistent with Ink4a/Arf and TP53 tumor suppressor function, BRafVE expression combined with mutation of either locus led to cancer progression.