ADAMTS Expression in Colorectal Cancer

ADAMTSs are a family of secreted proteinases that share the metalloproteinase domain with matrix metalloproteinases (MMPs). By acting on a large panel of extracellular substrates, they control several cell functions such as fusion, adhesion, proliferation and migration. Through their thrombospondin motifs they also possess anti-angiogenic properties. We investigated whether ADAMTSs participate in colorectal cancer progression and invasion. Their expression was investigated at both mRNA and protein levels. Using RT-PCR, the expression of ADAMTS-1, -4, -5 and ADAMTS-20 was estimated in colorectal tumors of different cancer stage and anatomic site and 3 cell lines of different aggressiveness. An overexpression of ADAMTS-4 and -5 was observed, especially in tissue samples, whereas ADAMTS-1 and -20 were found to be down-regulated. Western blot analysis further supported the RT-PCR findings, revealing in addition the degradation of ADAMTS-1 and -20 in cancer. In situ expression and localization of ADAMTS-1, -4, -5 and -20 was also investigated by immunohistochemical analysis. Our data suggest a positive correlation between ADAMTS-4 and -5 expression and cancer progression, in contrast with the anti-angiogenic members of the family, ADAMTS-1 and -20, which were found to be down-regulated. Our findings support the notion that overexpression of ADAMTS-4 and ADAMTS-5 in colorectal cancer might be a possible invasive mechanism of cancer cells in order to degrade proteoglycans of ECM.