Project description:The aim of this study was evaluate the transcriptome changes in the comparison between triple negative tumors with increased SPARC expression and triple negative tumors with decreased SPARC expression according to Nagai et al., 2011 (Breast Cancer Res Treat (2011) 126:1–14) The results generated could be of particular interest to better define the prognostic impact of SPARC expression in triple negative breast tumors
Project description:Integrative analysis of primary estrogen receptor-positive (ER+) breast cancer, triple-negative breast cancer (TNBC), and metaplastic breast cancer (MBC) tumors using Starfysh.
Project description:Comprehensive genomic analysis identify novel subtypes and targets of triple-negative breast cancer (67 not triple-negative tumors)
Project description:The remodeling of the extracellular matrix (ECM) by proteases releases fragments that promote tumor progression and metastasis. The protease cathepsin D (cath-D), a marker of poor prognosis in triple-negative breast cancer (TNBC), is aberrantly secreted in the ECM. Using degradomics, we discovered that the matricellular protein SPARC is a substrate of extracellular cath-D. In vitro, cath-D induced limited proteolysis of SPARC C-terminal extracellular Ca2+ binding domain at acidic pH, leading to the production of SPARC fragments (34-, 27-, 16-, 9-, and 6-kDa). Cath-D secreted by TNBC cells cleaved fibroblast- and cancer cell-derived SPARC at the tumor pericellular pH. SPARC cleavage also occurred in TNBC tumors. Among these fragments, the 9-kDa SPARC fragment inhibited TNBC cell adhesion and spreading, and stimulated their migration, endothelial transmigration and invasion more potently than full-length SPARC. Our study establishes a novel crosstalk between proteases and matricellular proteins in the ECM through limited proteolysis of SPARC, revealing a novel targetable 9-kDa bioactive SPARC fragment for TNBC.
