Thrombospondin-1 (TSP-1) stimulates expression of integrin 6 in human breast carcinoma cells: A downstream modulator of TSP-1-induced cellular adhesion

Thrombospondin-1 (tsp-1) is involved in a variety of different cellular processes including cell adhesion,tumor progression,and angiogenesis. this paper reports the novel finding that tsp-1 upregulates integrin 6 subunit in human keratinocytes and human breast cancer cells resulting in increased cell adhesion and tumor cell invasion. the effect of tsp-1 on 6 subunit expression was examined in human keratinocytes and breast adenocarcinoma cell lines (mda-mb-231) treated with tsp-1 and in tsp-1 stably transfected breast cancer cells. tsp-1 upregulated 6 message and protein in these cells as revealed by differential display,northern and western blot analysis and immunohistochemical localization studies. the increased expression of 6 was shown to mediate adhesion and invasion of these cells to laminin,a major component of the basement membrane and extracellular matrix (ecm). these data suggest that tsp-1 plays an integral role in the attachment of cells to the ecm facilitating cell motility and angiogenesis. copyright © 2010 anitha s. john et al.