Ovarian cancer spheroids constitute a metastatic niche for transcoelomic spread that also engenders drug resistance. Spheroid-forming cells express active STAT3 signaling and display stem cell-like properties that may contribute to ovarian tumor progression. In this study, we show that STAT3 is hyperactivated in ovarian cancer spheroids and that STAT3 disruption in this setting is sufficient to relieve chemoresistance. In an NSG murine model of human ovarian cancer, STAT3 signaling regulated spheroid formation and self-renewal properties, whereas STAT3 attenuation reduced tumorigenicity. Mechanistic investigations revealed that Wnt signaling was required for STAT3-mediated spheroid formation. Notably, the Wnt antagonist DKK1 was the most strikingly upregulated gene in response to STAT3 attenuation in ovarian cancer cells. STAT3 signaling maintained stemness and interconnected Wnt/β-catenin signaling via the miR-92a/DKK1-regulatory pathways. Targeting STAT3 in combination with paclitaxel synergistically reduced peritoneal seeding and prolonged survival in a murine model of intraperitoneal ovarian cancer. Overall, our findings define a STAT3-miR-92a-DKK1 pathway in the generation of cancer stem-like cells in ovarian tumors, with potential therapeutic applications in blocking their progression. .

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ANGPTL1 inhibits sorafenib resistance and cancer stemness in HCC cells by repressing EMT through inhibition of the MET receptor-AKT/ERK-Egr-1-Slug signaling cascade. ANGPTL1 may serve as a novel MET receptor inhibitor for advanced HCC therapy. (Hepatology 2016;64:1637-1651).

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Over-expression of AURKC has been detected in human colorectal cancers, thyroid carcinoma and several cancer cell lines. However, the regulation and clinical implications of over-expressed AURKC in cancer cells are unclear. Here we show that elevated AURKC increases the proliferation, transformation and migration of cancer cells. Importantly, the kinase activity of AURKC is required for these tumour-associated properties. Analysis of human cancer specimens shows that the expression of AURKC is increased in cervical cancer, and is highly correlated with staging in colorectal cancer. Over-expressed AURKC-GFP localizes to the centromeric regions of mitotic chromosomes and results in a decreased level of AURKB, a key regulator of spindle checkpoint. Expression of AURKC is down-regulated by PLZF, a transcriptional repressor, through recruitment to its promoter region. The expression levels of PLZF and AURKC mRNA display opposite patterns in human cervical and colorectal cancers. Taken together, our results provide important insights into human cancers with AURKC expression, which may serve as a potential target for cancer therapy in the future.