Endocrine dysfunction in p27Kip1 deficient mice and susceptibility to Wnt-1 driven breast cancer.

Publication Type:

Journal Article

Source:

Carcinogenesis, Volume 30, Issue 6, p.1058-63 (2009)

Keywords:

2009, Animals, Center-Authored Paper, Clinical Research Division, Comparative Medicine Core Facility, Cyclin-Dependent Kinase Inhibitor p27, estradiol, Female, Human Biology Division, Male, Mammary Neoplasms, Experimental, MICE, Mice, Knockout, Neoplasms, Hormone-Dependent, Ovariectomy, Pituitary Neoplasms, Progesterone, Research Trials Office Core Facility - Biostatistics Service, Shared Resources, Stomach Neoplasms, Wnt1 Protein

Abstract:

The cyclin-dependent kinase (Cdk) inhibitor p27(Kip1) (p27) is a marker of prognosis in many cancers, including breast cancer. Low p27 expression correlates with poor prognosis, especially in hormone receptor positive breast tumors. This association suggests a role for p27 in hormone-dependent cancer. We used the Wnt-1 transgenic mouse model to further explore the role of p27 in hormone-driven breast cancer. We found that p27 deficiency did not alter breast cancer rate in either male or female Wnt-1 mice. However, we did find p27-/- females had reduced levels of serum progesterone (P) and increased variability in estradiol (E), which could have affected their cancer susceptibility. To equalize hormone levels, an additional cohort of Wnt-1 female mice was ovariectomized and implanted with slow release pellets of E and P. Although this treatment did not alter the breast cancer rate, it did accelerate the development of pituitary and gastric tumors in p27-/- mice. This study shows that while not a significant inhibitor of Wnt-1-driven breast cancer, p27 inhibits gastric tumors, whose latency is modulated by sex steroids.