Shp2 Signaling Suppresses Senescence in PyMT-induced Mammary Gland Cancer in Mice [Mouse430A_2 array]

ABSTRACT: In this study, we have used techniques from cell biology, biochemistry, and genetics to investigate the role of the tyrosine phosphatase Shp2 in tumor cells of MMTV-PyMT mouse mammary glands. Genetic ablation or pharmacological inhibition of Shp2 induces senescence, as determined by the activation of senescence-associated β-gal (SA-β-gal), cyclin-dependent kinase inhibitor 1B (p27), p53, and histone 3 trimethylated lysine 9 (H3K9me3). Senescence induction leads to inhibition of self-renewal of tumor cells and blockage of tumor formation and growth. A signaling cascade was identified that acts downstream of Shp2 to counter senescence: Src, Focal adhesion kinase and Map kinase inhibit senescence by activating the expression of S-phase kinase-associated protein 2 (Skp2), Aurora kinase A (Aurka), and the Notch ligand Delta-like 1 (Dll1), which block p27 and p53. Remarkably, the expression of Shp2 and of selected target genes predicts human breast cancer outcome. We conclude that therapies which rely on senescence induction by inhibiting Shp2 or controlling its target gene products may be useful in blocking breast cancer. For Shp2 ablation, primary mammary tumor cells from MMTV-PyMT;Shp2fl/fl mice were transduced with retroviruses expressing control GFP or CreERT2-GFP, and GFP-positive cells were purified by FACS and cultured as mammospheres for 1 week. Mammospheres were then treated with 50 nM 4-OHT for 2 hours, cultured for another 5 days, and subjected to RNA isolation. For pharmacological inhibition, primary mammary tumor cells from the same mice were cultured as mammospheres for 10 days and then treated with the Shp2 inhibitor GS493 for another 2 days. Mammospheres were then subjected to RNA isolation. Each group contains 3 replicates.

ORGANISM(S): Mus musculus

SUBMITTER: Linxiang Lan 

PROVIDER: E-GEOD-50516 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress