CD133~+Positive Ovarian Cancer Stem-like Cells Differentiate To Vascular Endothelial Cells

Objectives:Ovarian cancer is one of the common malignant tumor in women, whose morbidityjust follows cervical cancer and endometrium cancer, ranking the3rdin womenreproductive system. Because of few early stage symptom, patient are often found to beadvanced stage at diagnosis. Clinically, patients’5-years overal survival is25%. Thereafter,studies in tumorigenesis, progress and metastasis and recurrence of ovarian cancer will beof great importance in improving early diagnosis rate and clinical treatment of ovariancancer. Tumor vascularity play important role in tumor growth, invasiveness and metastasis.Traditionally, cytokine and chemokine such as VEGF secreted by tumor cell allure vesselsgrow towards tumor and recruit endothelial cell to tumor site, named angiogenesis andneovasculature. Recent studies find heterogeneity in tumor and named a smallsubpopulation cell cancer stem cells (CSCs) who have stem cell properties such as selfrenew and pluripotent differentiation and CD133marker. Studies on CSC validate that CSCcan differentiate to endothelial cell in a number of tumor. However, rare reports have focuson CSCs differentiation to endothelial in ovarian cancer. This study was intended to explorethe steps and characteristic of CSCs diffentiation to vascular endothelial in ovarian cancerand the underlying mechanism, and will provide a novel target to anti-angiogenesis.Methods:The A2780cells were cultured preliminary in serum-free medium in order to induceCD133+ovarian cancer stem-like cells (CD133+OCSLCs). Matrigel tube-forming assay wasproformed to test the ability of CD133+OCSLCs to differentiate into vascular endothelialcells, which were validated by CD31expression with the use of RT-PCR and western blot,in which human umbilical venous endothelial cells (HUVECs) was used as as positivecontrol. CCL5stumulation was proformed in vitro so as to explore its function toCD133+OCSLC in Matrigel tube-forming assay. Unsing sh-RNA specific to CCL5, the CD133+OCSLCs and its CCL5knockdowncounterpart cells were xenografted to nude mice subcutaneously and immunofluorescencestaining of human specific endothelia markers in transplanted tumor tissue was used toinvestigate the differentiation ability and tube-forming ability of CD133+OCSLCsindividually in vivo.Results:1. CD133+OCSLCs can form vessel-like tube in Matrigel tube-forming assay.2. Immunofluorescence, RT-PCR and western blot results validated that humanspecific CD31was significantly overexpressed in CD133+OCSLCs with Matrigeltube-forming assay(P＜0.01).3. Immunofluorescence of xenografts in nude mice staining with human specific CD31showed that human vessels existed in tumor tissue, supporting the hypothesis ofCD133+OCSLCs differentiating to tumor vascular endothelial cells in vivo.4. CCL5promoted CD133+OCSLCs to form vessal-like tube through CCR1/3/5butdid not effect its differentiating to vascular endothelial cell.Conclusions:CD133+OCSLCs partly possessed vascular endothelial cell differentiation function in aCCL5dependent manner which uncovered a novel mechanism of ovarian angiogenesisderived from CD133+OCSLCs and may provide novel target in anti-angiogenesis therapy ofovarian cancer...