Low omega-3 polyunsaturated fatty acid status predicts reduced response to standard antidepressants in patients with major depressive disorder

Abstract

The mammary epithelium undergoes several rounds of extensive proliferation during the female reproductive cycle. Its expansion is a tightly regulated process, fueled by the mammary stem cells and these cells' unique property of self-renewal. Sufficient new cells have to be produced to maintain the integrity of a tissue, but excessive proliferation resulting in tumorigenesis needs to be prevented. Three well-known tumor suppressors, p53, p16INK4a, and p19ARF, have been connected to the limiting of stem cell self-renewal and proliferation. Here we investigate the roles of these three proteins in the regulation of self-renewal and proliferation of mammary epithelial cells. Using mammary epithelial-specific mouse models targeting Trp53 and Cdkn2a, the gene coding for p16INK4a and p19ARF, we demonstrate that p53, p16INK4a, and p19ARF do not play a significant role in the limitation of normal mammary epithelium self-renewal and proliferation, whereas in the presence of the inflammatory cytokine TNF-α, Trp53−/− Cdkn2a−/− mammary basal cells exhibit amplified proliferation.