Enhanced expression of ADAMTS1 in ovarian carcinomas: loss of ADAMTS1 expression instigates cellular reprogramming of extracellular matrix ensuing altered plasticity, augmented migration and attenuated adhesion.

Abstract

Background: ADAMTS1, a disintegrin and metalloproteinase with thrombospondin motif 1, plays a role in inflammation, organogenesis, and ovulation. Up or downregulation of ADAMTS1 has been implicated in tissue remodelling leading to cancer. We analysed the expression of ADAMTS1 in different stages/grades of primary and metastatic serous ovarian tumours and ascites-derived tumour cells from patients and assessed the functional role of ADAMTS1 in ovarian cancer (OC) cell lines.

Methods: The expression and localisation of ADAMTS1 was assessed by immunohistochemistry (IHC) and Opal Multiplex IHC staining of OC tissues. Functional roles of ADAMTS1 in OC cell lines were assessed by using siRNA-mediated knockdown (KD), MTT assay, cell migration by xCELLigence, cell adhesion, ELISA, qRT-PCR, Western blot, immunofluorescence (IF) and activity of Cdc42 GTPase.

Results: The expression of ADAMTS1 was significantly enhanced in higher stages/grades of ovarian tumours compared to benign tumours. In high-grade tumours, ADAMTS1 was localised more in the nucleus of epithelial cells while localisation in stromal cells was mostly in the cytoplasm. Significantly higher mRNA expression of ADAMTS1 was noted in epithelial compared to mesenchymal ascites-derived tumour cells. The expression of ADAMTS1 was significantly higher in metastatic high-grade tumours compared to primary tumours. KD of ADAMTS1 expression by siRNA in OC cell lines had no effect on cell proliferation but resulted in decreased cell adhesion, increased cell migration accompanied by increased expression of markers (CDH1 and EPCAM) associated with epithelial plasticity. Remodelling of ECM accompanied by increased intra- and extracellular production of VCAN and enhanced Cdc42 GTPase activity was also noted in cell lines with ADAMTS1 KD. Cdc42 GTPase specific inhibitor, ML141, reversed ADAMTS1 KD-mediated enhanced migration. On the other hand, VCAN KD inhibited ADAMTS1 KD-mediated migration and reversed the effect on cell adhesion.

Conclusions: These results suggest that the expression of ADAMTS1 progressively enriches ovarian tumours and promotes OC progression. Its knock down in in vitro cell culture impacts ECM remodelling through enhanced Cdc42GTPase activity and VCAN production resulting in epithelial cell plasticity, accelerated migration, and reduced cell adhesion.