Liu L.,Institute of Pathology and Southwest Cancer Center |
Chen X.,Institute of Pathology and Southwest Cancer Center |
Cheng J.,Institute of Pathology and Southwest Cancer Center |
Zhang H.,Institute of Urology Surgery |
And 5 more authors.
Hepatology | Year: 2016
Hepatocellular carcinoma (HCC) is a highly aggressive liver tumor containing cancer stem cells (CSCs) that participate in tumor propagation, resistance to conventional therapy, and promotion of tumor recurrence, causing poor patient outcomes. The protein SRY (sex determining region Y)-box 9 (Sox9) is a transcription factor expressed in some solid tumors, including HCC. However, the molecular mechanisms underlying Sox9 function in liver CSCs remain unclear. Here, we show that Sox9 is highly expressed in liver CSCs and that high levels of Sox9 predict a decreased probability of survival in HCC patients. We demonstrate that Sox9 is required for maintaining proliferation, self-renewal, and tumorigenicity in liver CSCs. Overexpression of exogenous Sox9 in liver non-CSCs restored self-renewal capacity. Additionally, a reduction in the asymmetrical cell division of spheroid-cultured liver CSCs was observed when compared with differentiated cancer cells or liver CSCs with inhibited Notch signaling. Furthermore, we demonstrate that Sox9 is responsible for the asymmetrical-to-symmetrical cell division switch in liver CSCs. Sox9 also negatively regulates Numb expression, contributing to a feedback circuit that maintains Notch activity and directs symmetrical cell division. Clinical analyses revealed that the Sox9HighNumbLow profile is associated with poor prognosis in human HCC patients. Conclusion: We demonstrate that Sox9 plays a critical role in self-renewal and tumor propagation of liver CSCs and identify the molecular mechanisms regulated by Sox9 that link tumor initiation and cell division. © 2016 by the American Association for the Study of Liver Diseases.
Hu Q.-P.,Institute of Pathology and Southwest Cancer Center |
Kuang J.-Y.,Institute of Pathology and Southwest Cancer Center |
Yang Q.-K.,Dalian Medical University |
Bian X.-W.,Institute of Pathology and Southwest Cancer Center |
Yu S.-C.,Institute of Pathology and Southwest Cancer Center
International Journal of Cancer | Year: 2016
E-cadherin (E-cad) plays important roles in tumorigenesis as well as in tumor progression, invasion and metastasis. This protein exists in two forms: a membrane-tethered form and a soluble form. Full-length E-cad is membrane tethered. As a type I transmembrane glycoprotein, E-cad mainly mediates adherens junctions between cells and is involved in maintaining the normal structure of epithelial tissues. Soluble E-cad (sE-cad) is the extracellular fragment of the protein that is cleaved from the membrane after proteolysis of full-length E-cad. The production of sE-cad undermines adherens junctions, causing a reduction in cell aggregation capacity; furthermore, sE-cad can diffuse into the extracellular environment and the blood. As a paracrine/autocrine signaling molecule, sE-cad activates or inhibits multiple signaling pathways and participates in the progression of various types of cancer, such as breast cancer, ovarian cancer, and lung cancer, by promoting invasion and metastasis. This article briefly reviews the role of sE-cad in tumorigenesis and tumor progression and its significance in clinical therapeutics. © 2015 UICC.