Figure 2. MK2-expressing and MK2-deficient tumors develop in a murine autochthonous model of Non-Small Cell Lung Cancer.

(A) Combinations of MK2, Kras and p53 alleles used in this study: MK2^+/+ or MK2^CV/CV mice harbour one copy of the K-ras^LSL-G12D allele in a wildtype p53 background (p53^+/+), or they contain two copies of the p53^flox allele (p53^flox/flox). After Cre-mediated recombination, the respective tumor MK2 status in MK2^+/+ and MK2^CV/CV mice is indicated as “MK2+” for MK2-expressing tumors, and “MK2-“ for MK2-negative tumors, exclusively found in MK2^CV/CV mice.

(B) Tumors from a MK2^+/+;Kras^LSL-G12D/+;p53^fl/fl mouse at the experimental endpoint were stained with haematoxilin and eosin (H&E, left) or by IHC for MK2 (brown staining, middle). Right: close-up of three MK2+ tumors. Scale bar = 50µm

(C) Tumors from a MK2^CV/CV;Kras^LSL-G12D/+;p53^fl/fl mouse at the experimental endpoint, stained as in panel B. Right: close-up of MK2+ tumor (brown staining) and MK2− tumor (blue counterstain only). MK2 expressing stroma cells infiltrate and surround an MK2-negative tumor (arrows). In B and C, the experimental endpoint corresponds to 20% basal weight loss of tumor bearing animals.