Evidence for the antagonistic form of CXC-motif chemokine CXCL10 in serous epithelial ovarian tumours.

Patients with high-grade, serous epithelial ovarian carcinoma (HGSOC) are generally diagnosed with extensive peritoneal metastases, and exhibit 5-year survival rates <30%. A subset of these tumours, defined as "immunoreactive," overexpress mRNA encoding the T-cell-recruiting chemokine CXCL10 (10-kDa interferon gamma-induced protein; C-X-C motif chemokine 10). Tumour-infiltrating CD4(+) CD8(+) T-cells are a well-documented, positive prognostic indicator for HGSOC patients; paradoxically, however, patients diagnosed with HGSOC (overexpressing CXCL10 and therefore theorised to recruit T-cells) typically exhibit poor survival. Recently, an "antagonistic" CXCL10 variant was identified that inhibited leucocyte recruitment to inflamed liver in vivo (Casrouge et al., J Clin Invest 2011;121:308-17). We hypothesised that "immunoreactive" HGSOC might also express antagonistic CXCL10, interfering with leucocyte recruitment and contributing to poor patient prognosis. CXCL10 expression was analysed in HGSOC tissues grouped according to pathology, grade and FIGO stage at diagnosis, and its localisation and association with T-cells established by immunohistochemical staining in tissue microarrays. CXCL10 expression was increased in a subset of serous epithelial tumour samples; however, it did not correlate well with CD45-positive tumour infiltrate. Immunoprecipitation and de novo sequence analysis of CXCL10 identified the N-terminally cleaved, "antagonistic" variant of CXCL10 specifically in malignant tumours, and not in benign ovarian disease. The data demonstrate the presence of the antagonistic form of CXCL10 in HGSOC for the first time, and provide a partial explanation for reduced leucocyte infiltration observed in these tumours. We suggest that CXCL10 cleavage and subsequent antagonism of immune cell recruitment may be a feature of the "immunoreactive" HGSOC subtype, leading to early impairment of the immune response and subsequently worsening patient prognosis.

A novel marker of human endometrial mesenchymal stem-like cells.

Coexpression of CD140b (PDGFRß) and CD146 has been used to isolate endometrial mesenchymal stem-like cells (eMSCs), which have a perivascular location. This study aims to evaluate a single marker for purifying eMSCs. Using an antibody panel with novel specificities, we screened human endometrial tissues and stromal cell suspensions by flow cytometry and immunohistochemistry to identify perivascular markers. Sorted subpopulations were examined for colony-forming unit (CFU), self-renewal, and differentiation assays for mesenchymal stem cell (MSC) function. We also transplanted sorted eMSCs under the kidney capsule of superimmunodeficient NSG mice. Magnetic bead selection was compared with flow cytometry sorting (flow sorting) using CFU assay. One novel marker (W5C5) was particularly effective in selecting eMSCs. W5C5(+) cells comprise 4.2±0.6% (n = 34) of endometrial stromal cells and reside predominantly in a perivascular location in both basal and functional layers of endometrium. The clonogenicity of W5C5(+) cells is significantly greater than W5C5(-) and unselected cells. W5C5(+) cells differentiated into adipocytes, osteocytes, chondrocytes, myocytes, and endothelial cells. W5C5(+) cells produce endometrial stromal-like tissue in vivo. In terms of clonogenicity, magnetic bead-selected W5C5(+) cells gave rise to significantly higher CFU numbers compared to flow-sorted W5C5(+) cells. This study identified W5C5 as a single marker capable of purifying eMSCs possessing MSC properties and reconstituting endometrial stromal tissues in vivo. W5C5 enriches eMSCs to high purity and provides a simple protocol for their prospective isolation using magnetic bead selection rather than flow sorting. W5C5 selection may provide an alternate, readily available autologous source of MSC, obtainable with minimal morbidity using an office endometrial biopsy procedure for future cell-based therapies.