Thromboxane A2 receptor‐mediated release of matrix metalloproteinase‐1 (MMP‐1) induces expression of monocyte chemoattractant protein‐1 (MCP‐1) by activation of protease‐activated receptor 2 (PAR2) in A549 human lung adenocarcinoma cells

Abstract Matrix metalloproteinases (MMPs) and monocyte chemoattractant protein‐1 (MCP‐1, CCL2) are known to be upregulated in many tumors. Their roles in tumor invasion and metastasis are being uncovered. How they are related to each other and involved in tumor progression remains to be determined. Earlier it was reported that I‐BOP‐initiated activation of thromboxane A2 receptor (TP) induced the release of MMP‐1, MMP‐3, and MMP‐9 from lung cancer A549 cells overexpressing TPα (A549‐TPα). Herein it was found that MMP‐1, but not MMP‐3 or MMP‐9, induced the expression of MCP‐1 in A549 cells. Conditioned medium (CM) from I‐BOP activated, MMP‐1 siRNA pretreated A549‐TPα cells induced greatly attenuated expression of MCP‐1 in A549 cells indicating that MMP‐1 in the CM contributed significantly to the expression of MCP‐1. MMP‐1 was shown to activate protease‐activated receptor 2 (PAR2) instead of commonly assumed PAR1 to increase the expression of MCP‐1 in A549 cells. This conclusion was reached from the following findings: (1) expression of MCP‐1 induced by trypsin, a PAR2 agonist, and also PAR2 agonist peptide, was inhibited by a PAR2 antagonist; (2) expression of MCP‐1 induced by MMP‐1 and by CM from I‐BOP activated A549‐TPα cells was blocked by a PAR2 antagonist but not by other PAR antagonists; (3) expression of MCP‐1 induced by MMP‐1 and by CM from I‐BOP activated A549‐TPα cells was attenuated significantly by p...
Source: Molecular Carcinogenesis - Category: Molecular Biology Authors: Tags: Research Article Source Type: research