Abstract 3378: Discoidin domain receptor 2 differentially controls HT-1080 cell proliferation in young-adult and old type I collagen 3D matrices

Abstract

Abstract Type I collagen plays a key role in tumor proliferation, adhesion and migration. We have recently demonstrated that this fibrillar and life-long protein undergoes detrimental changes in biochemical and biomechanical properties during aging (1). In addition to a high Advanced Glycation End-products (AGE) and cross-links content, old collagen exhibits a significant loss in fibrillar properties. In this study, we analyzed the effect of collagen aging on human HT-1080 fibrosarcoma cell proliferation in 3D matrix model. For this, type I collagen was extracted from tail tendons of young-adult (2 months) and old (2 years) rats. In 3D matrix, the rate of HT-1080 cell growth was significantly lower in young-adult collagen. This was accompanied by a down-regulation of ERK1/2 phosphorylation and an increase in the cyclin-dependent kinase inhibitor p21 expression. Blocking antibodies and siRNA strategy against β1 integrin and AGEs receptor (RAGE) did not increase cell growth in young-adult collagen. Accumulating evidence suggest that Discoidin Domain Receptor 2 (DDR2) is a receptor tyrosine kinase with the unique ability to be activated by fibrillar collagen. To determine whether differential DDR2 responses are elicited by the two collagens, DDR2 was immunoprecipitated from cell lysates, and its phosphorylated form was detected by immunoblotting. DDR2 phosphorylation level was increased in young-adult collagen. This was accompanied by an increase in the tyrosine phosphatase SHP2 phosphorylation, the primary target of DDR2. Interestingly, the DDR2 inhibitor nilotinib was able to restore cell proliferation in young-adult collagen. In addition to an increase in ERK1/2 phosphorylation, nilotinib decreased SHP2 phosphorylation and p21 expression. Taken together, these data show that age-associated changes of type I collagen organization, especially fibrillar properties, are critical for tumor cell proliferation control by DDR2.