Bradykinin Promotes Cell Proliferation, Migration, Invasion, and Tumor Growth of Gastric Cancer Through ERK Signaling Pathway

Bradykinin (BK) has been reported to be involved in the progression of diverse types of cancer. In the present study, we investigated the possible role of BK in cell proliferation, migration, invasion, and tumor growth of gastric cancer (GC). Cell proliferation was evaluated by MTT assays. Cell migration and invasion were assessed by Transwell assays. Tumor growth of nude mice was detected by establishing subcutaneous xenograft tumor model. Silencing of bradykinin B1 receptor (B1R) and the bradykinin B2 receptor (B2R) was performed by transfecting cells with si-B1R and si-B2R, respectively. The protein expression levels of phospho-ERK1/2 (p-ERK1/2), matrix metalloproteinase (MMP)-2, MMP-9, and E-Cadherin were examined by Western blot. Data revealed that BK promoted cell proliferation, migration, invasion, and the in vivo tumor growth of GC cells SGC-7901 and HGC-27. Furthermore, BK elevated the protein levels of p-ERK1/2, MMP-2, and MMP-9, but reduced E-Cadherin. In addition, by repressing B2R using si-B2R or inhibiting ERK signaling pathway using PD98059, BK-mediated promotion of cell proliferation, migration, and invasion and upregulation of p-ERK1/2, MMP-2/9, as well as downregulation of E-Cadherin were attenuated. Taken together, the present study demonstrated that BK promoted cell proliferation, migration, invasion, and tumor growth by binding to B2R via ERK signaling pathway. Our findings may provide promising options for the further treatment of GC. J. Cell. Biochem. 118: 4444-4453, 2017. (c) 2017 Wiley Periodicals, Inc.