Figures & data
Figure 1. Mechanism of OSM-mediated senescence and its inactivation by c-Myc in premalignant mammary epithelial cells. Premalignant mammary epithelial cells that lack expression of p16 and p53 readily acquire senescent phenotypes in the presence of OSM. The ability of OSM to induce senescence requires autocrine TGF-β signaling and the formation of novel Stat3:Smad3 complexes (Circle 1) that accumulate in the nucleus to repress c-Myc expression, while simultaneously inducing that of p16 and p21 (Circle 2). Escaping senescence programs during malignant progression can be initiated by aberrant c-Myc expression, which endows OSM with tumor promoting functions and the ability to induce breast cancer cells to grow in an anchorage-independent manner, to exhibit increased invasiveness, and to undergo EMT programs driven by Snail (Circle 3). Red lettered circles correspond to provided unanswered questions and future directions (right panel). Abbreviations: AIG, anchorage-independent growth. IL-6, interleukin-6; IL-11, interleukin-11; LIF, leukemia inhibitory factor; MMPs, matrix metalloproteinases; OSMR, OSM receptor; TβR-I, TGF-β type I receptor; TβR-II, TGF-β type II receptor; TGF-βR, TGF-β receptors.
