Normal ovarian surface epithelial label-retaining cells exhibit stem/progenitor cell characteristics

Abstract

Ovulation induces cyclic rupture and regenerative repair of the ovarian coelomic epithelium. This process of repeated disruption and repair accompanied by complex remodeling typifies a somatic stem/progenitor cell-mediated process. Using BrdU incorporation and doxycycline inducible histone2B-green fluorescent protein pulse–chase techniques, we identify a label-retaining cell population in the coelomic epithelium of the adult mouse ovary as candidate somatic stem/progenitor cells. The identified population exhibits quiescence with asymmetric label retention, functional response to estrous cycling in vivo by proliferation, enhanced growth characteristics by in vitro colony formation, and cytoprotective mechanisms by enrichment for the side population. Together, these characteristics identify the label-retaining cell population as a candidate for the putative somatic stem/progenitor cells of the coelomic epithelium of the mouse ovary.

Human ovarian cancer stem/progenitor cells are stimulated by doxorubicin but inhibited by Mullerian inhibiting substance

“…2A, control; Fig. S5), which supports our previous finding in normal ovarian surface epithelium (20). However, when separated cells were treated with MIS or doxorubicin for 14 d, MIS significantly inhibited colony growth of the 3+Ecad− cells (Fig.…”

“…2G), whereas the kinases tested were unaffected (data not shown). Self-renewing normal somatic stem cells are housed in a niche, where they are slowly cycling, as illustrated by label retention (20,42); committed progenitors, when released from the confines of a niche, undergo rapid cycling for effective expansion (43). MIS treatment resulted in G1 accumulation in the 3+Ecad− cells compared with the 3−Ecad+ population; by contrast, doxorubicin decreased the percentage of the 3+Ecad− cells in G1, indicating that the MIS may be exerting molecular effects similar to those extant in a normal niche.…”

“…Colony formation assays were performed as previously described (5). SKOV-3 or OVCAR-5 cells separated by FACS were recovered, plated on six-well plates containing 2 mL complete DMEM with 10% FCS, incubated for 14 d at 37°C, and stained with Giemsa, and the stained area was measured as a fraction of the area of each well (Image J Rasband, National Institutes of Health; http://rsb.info.nih.gov/ij/) (20). Cells separated from primary ascites (9) were plated in agarose on 12-well (22-mm) plates (BD Biosciences) at 50,000 cells/well in 0.4% low-melting-temperature agarose (FMC BioProducts; catalog 50113) over a 0.8% layer and incubated for 2-3 wk at 37°C.…”

Epithelial ovarian cancer stem cells: underlying complexity of a simple paradigm

“…The LRCs were identified in murine OSE 3 months after transient labelling (Szotek et al 2008). Importantly, the LRCs were able to enter a proliferative phase during ovulation in vivo and to have enhanced growth potential in vitro.…”

“…The somatic stem cells in the OSE have been investigated in three distinct contexts: potential stem cells able to regenerate germ cells (Parte et al 2011, Patel et al 2013, Virant-Klun et al 2013a, potential stem cells that give rise to granulosa cells (Hummitzsch et al 2013), and more traditional somatic stem cells whose role is to replenish the OSE following ovulatory wounding (Szotek et al 2008, Motohara et al 2011, Usongo & Farookhi 2012, Auersperg 2013, Flesken-Nikitin et al 2013, Ng et al 2014. While this review focuses briefly on studies that have addressed somatic stem cells that are thought to be required for ovulatory wound repair, the relationship with the HGSEOC of the two former potential stem cell pools cannot be discounted.…”