Investigation of Tenascin-C Effects on Thrombospondin 1 in Highly Invasive Breast Cancer Cell Lines

Breast cancer is the most diagnosed cancer among women worldwide. Tenascin-C (TNC) is a high glycoprotein which has been shown to be over-expressed in the breast cancer stroma and promotes cancer progression. Thrombospondin 1 (TSP-1) is an adhesive which has been shown to play roles in platelet aggregation, , and . The aim of this study was to investigate the effects of TNC knockdown in TSP-1 expression in highly invasive breast cancer cell lines. Small interfering RNA (siRNA) targeting total TNC and high molecular TNC isoforms (TNC-14 and TNC-14-AD1) were transfected into the highly invasive MDA-MB-231 breast cancer cell line. The alterations caused by TNC knockdown on TSP-1 were analysed at protein level by Western blot using conditioned media. The expression of TSP-1 was significantly up-regulated as a result of TNC down-regulation. In conclusion, TNC knockdown significantly increases TSP-1 expression, confirming their importance in tumorigenesis.