Sanguinarine targets the catalytic domain of MMP-9: Molecular dynamics and in vitro studies in MDA-MB 468 breast cancer cells

Abstract

Matrix metalloproteinase 9 (MMP9) belongs to a group of endopeptidases. It is functionally involved in the proteolytic degradation of extracellular matrix proteins in various pathophysiological conditions. MMP9 is overexpressed in several cancers and is crucial for metastatic progression of triple negative breast cancer (TNBC). Because of its etiological significance in TNBC, it is considered a potential therapeutic target. In this study, our in silico studies demonstrated that Sanguinarine (SAN) could directly binds to catalytic domain (CD) of MMP9 via key amino acid residues involved in its enzymatic function. Docking studies using CB Dock, PyRx, Seam Dock, and 1-click docking have predicted that SAN binds the MMP9-CD with a binding affinity of −8.5 kcal/mol. Further, our docking studies also showed that structural derivatives of SAN bind to the CD of MMP9 with almost the same affinity as SAN. Structural derivatives 10-hydroxydihydrosanguinarine, dihydrosanguinarine, ethoxysanguinarine, and norsanguinarine were found to bind the MMP9-CD with binding affinities −8.3 kcal/mol,-8.2 kcal/mol,-7.5 kcal/mol, and -8.3 kcal/mol, respectively. Molecular dynamics simulation studies strongly validated our docking results showing that SAN forms stable interactions with critical amino acid residues Leu188, Tyr393, and Met 422 within the catalytic site of MMP9. Further, the effect of SAN on activity and expression of MMP9 was validated in MDA-MB 468, a TNBC cell line, along with known MMP9 inhibitor, Amentoflavone (AMF). Both SAN and AMF reduced the viability and proliferation of TNBC cells by damaging the cell integrity. On the whole, our study shows that SAN can directly inhibit MMP9 by binding to its CD and viability of breast cancer cells.