Fig. 1: LMW-E drives salivary gland tumorigenesis, independent of CDK2 status.
A Representative cross of transgenic MMTV-LMW-E-T1 and p53+/−, CDK2+/− to generate isogenic CDK2 (+/+, +/−, and −/−) MMTV-LMW-E-T1-p53+/− mice. B Percentage of tumor-free mice among MMTV-LMW-E-T1; p53+/−; isogenic for CDK2. CDK2+/+ (n = 13, dark blue line), CDK2+/− (n = 15, light blue line) and CDK2−/− (pink line, n = 12); compared to incidence of mammary tumors (green line, n = 12) in MMTV-LMW-E; p53+/−; CDK2−/− mice. Log-rank Mantel–Cox test was used to compare survival between the indicated genotypes. Samples sizes were estimated using the G power software. Data from our previous publication17 was used to estimate the differences between different CDK2 backgrounds. Mice were grouped by CDK2 genetic status without a need for randomization. C The murine parotid salivary gland (P) expanded and effaced by an adenocarcinoma (*). Unaffected salivary glands and adjacent structures including the sublingual salivary gland (SL), submandibular salivary gland (SM), exorbital lacrimal gland (EL), and mandibular lymph node (MLN) are shown in a CDK2−/− tumor (H&E, 0.6×). Inset: murine parotid salivary gland (P) expanded and effaced by an adenocarcinoma (*) in CDK2+/+ tumors (H&E, 2×). D Multiple histologic patterns within individual tumors and between tumors from CDK2+/+, CDK2+/−, and CDK2−/− mice. Typical histologic patterns including trabecular (A), acinar (B), and solid (C) (H&E, 20x). E Input (10%) using 25 μg protein was subject western blot analysis of salivary gland tumor lysates from MMTV-LMW; p53+/−; CDK2+/+ or CDK2−/− mice for the indicated markers. F Immunoprecipitation (IP) with cyclin E using 250 μg of salivary gland tumor lysates from (E) in MMTV-LMW; p53+/−; CDK2+/+ or CDK2−/− mice, followed by western blot analysis of the indicated markers. G Histone H1 (HH1) kinase assay to measure cyclin E associated kinase activity, with (Yes) or without (No) 3 rounds of immunodepletion (ID) of CDK1 from salivary gland tumor MMTV-LMW; p53+/−; CDK2+/+ (3085) or CDK2−/− (4111) mice. B1–B3 in both samples corresponds to beads after the first-third round of ID and S3 corresponds to the supernatant protein lysate used after the third round of ID showing >90% ID of CDK1.
