Targeting cancer stem cell signature gene SMOC-2 Overcomes chemoresistance and inhibits cell proliferation of endometrial carcinoma.

BACKGROUND: Endometrial cancer is one of the most common gynecological malignancies and has exhibited an increasing incidence rate in recent years. Cancer stem cells (CSCs), which are responsible for tumor growth and chemoresistance, have been confirmed in endometrial cancer. However, it is still challenging to identify endometrial cancer stem cells to then target for therapy. METHODS: Flow cytometry was used to identify the endometrial cancer stem cells. Sphere formation assay, western blotting, qRT-PCR assay, cell viability assay, xenograft assay and immunohistochemistry staining analysis were utilized to evaluate the effect of SPARC-related modular calcium binding 2 (SMOC-2) on the cells proliferation and drug resistance. Cell viability assay, qRT-PCR assay, immunofluorescence staining, Co-IP assay and luciferase reporter gene assay were performed to explore the possible molecular mechanism by which SMOC-2 activates WNT/ß-catenin pathway. FINDINGS: We found the expression of SPARC-related modular calcium binding 2 (SMOC-2), a member of SPARC family, was higher in endometrial CSCs than that in non-CSCs. SMOC-2 was also more highly expressed in spheres than in monolayer cultures. The silencing of SMOC-2 suppressed cell sphere ability; reduced the expression of the stemness-associated genes SOX2, OCT4 and NANOG; and enhanced chemosensitivity in endometrial cancer cells. By co-culture IP assay, we demonstrated that SMOC-2 directly interacted with WNT receptors (Fzd6 and LRP6), enhanced ligand-receptor interaction with canonical WNT ligands (Wnt3a and Wnt10b), and finally, activated the WNT/ß-catenin pathway in endometrial cancer. SMOC-2 expression was closely correlated with CSC markers CD133 and CD44 expression in endometrial cancer tissue. INTERPRETATION: Taken together, we conclude that SMOC-2 might be a novel endometrial cancer stem cell signature gene and therapeutic target for endometrial cancer. FUND: National Natural Science Foundation of China, Scientific and Technological Innovation Act Program of Shanghai Science and Technology Commission, Scientific and Technological Innovation Act Program of Fengxian Science and Technology Commission, Natural Science Foundation of Shanghai.

Narrowing Resection of Parametrial Tissues Is Feasible in Low-Risk Cases of Stage IA2-IB1 Cervical Cancer.

BACKGROUND: Radical hysterectomy with pelvic lymphadenectomy is the standard surgical treatment for patients with stage IA2-IB1 cervical cancer, but the wide excision increases the complications. OBJECTIVE: To analyze the feasibility of narrowing resection of parametrial tissues in stage IA2-IB1 cervical cancer. STUDY DESIGN: Retrospectively analyzed the pathological and clinical data of patients with stage IA2-IB1 cervical cancer who received radical hysterectomy with pelvic lymphadenectomy in OB/GYN Hospital, Fudan University, China from Jan 2008 to Dec 2011. The affected factors of parametrial metastases and outcomes were discussed. The single factor analysis was made with χ2 test, and the relationship of the resection width of parametrial tissues and the patients' outcomes was analyzed with χ2 test and log-rank. P-values <0.05 were considered statistically significant. RESULTS: There were 31 cases recurred, 26 cases died of cervical cancer in 513 patients during the follow-up period (from 2 months to 66 months, averaged 39 months). The low-risk factors included diameter of tumor ≤2cm, depth of cervical myometrial invasion<1/2 and without lymph vascular involvement. There were no parametrial metastases in cases with all three low-risk factors. Whether the resection width of parametrial tissues ≥3cm or not had no statistically significant effect on progression free survival (PFS) or overall survival (OS) of low-risk patients. D2-40 and CD31 were related with parametrial metastases, but not with recurrence or outcomes. CONCLUSIONS: The resection width of parametrial tissues has no effect on PFS and OS of low-risk patients, and narrowing resection of parametrial tissues (<3cm) is feasible.