ABSTRACT
Prostate cancer is the most commonly diagnosed malignancy in men and shows a tendency for metastasis to distant organs. Angiogenesis is required for metastasis. Bradykinin (BK) is an inflammatory mediator involved in tumor growth and metastasis, but its role in vascular endothelial growth factor (VEGF) expression and angiogenesis in human prostate cancer remains unknown. The aim of this study was to examine whether BK promotes prostate cancer angiogenesis via VEGF expression. We found that exogenous BK increased VEGF expression in prostate cancer cells and further promoted tube formation in endothelial progenitor cells and human umbilical vein endothelial cells. Pretreatment of prostate cancer with B2 receptor antagonist or small interfering RNA (siRNA) reduced BK-mediated VEGF production. The Akt and mammalian target of rapamycin (mTOR) pathways were activated after BK treatment, and BK-induced VEGF expression was abolished by the specific inhibitor and siRNA of the Akt and mTOR cascades. BK also promoted nuclear factor-κB (NF-κB) and activator protein 1 (AP-1) activity. Importantly, BK knockdown reduced VEGF expression and abolished prostate cancer cell conditional medium-mediated angiogenesis. Taken together, these results indicate that BK operates through the B2 receptor, Akt, and mTOR, which in turn activate NF-κB and AP-1, activating VEGF expression and contributing to angiogenesis in human prostate cancer cells.
Subject(s)
Bradykinin/physiology , Gene Expression Regulation, Neoplastic , Neovascularization, Pathologic/pathology , Prostatic Neoplasms/metabolism , Vascular Endothelial Growth Factor A/biosynthesis , Cells, Cultured , Human Umbilical Vein Endothelial Cells , Humans , Male , Neovascularization, Pathologic/physiopathology , Vascular Endothelial Growth Factor A/agonistsABSTRACT
Prostate cancer is the most commonly diagnosed malignancy in men and shows a predilection for metastasis to distant organs. Bradykinin (BK) is an inflammatory mediator and has recently been shown to mediate tumor growth and metastasis. The adhesion molecule intercellular adhesion molecule-1 (ICAM-1) plays a critical role during tumor metastasis. The aim of this study was to examine whether BK promotes prostate cancer cell migration via ICAM-1 expression. The motility of cancer cells was increased following BK treatment. Stimulation of prostate cancer cells with BK induced mRNA and protein expression of ICAM-1. Transfection of cells with ICAM-1 small interfering RNA reduced BK-increased cell migration. Pretreatment of prostate cancer cells with B2 receptor, phosphatidylinositol 3-kinase (PI3K), Akt, and activator protein 1 (AP-1) inhibitors or mutants abolished BK-promoted migration and ICAM-1 expression. In addition, treatment with a B2 receptor, PI3K, or Akt inhibitor also reduced BK-mediated AP-1 activation. Our results indicate that BK enhances the migration of prostate cancer cells by increasing ICAM-1 expression through a signal transduction pathway that involves the B2 receptor, PI3K, Akt, and AP-1. Thus, BK represents a promising new target for treating prostate cancer metastasis.
Subject(s)
Bradykinin/pharmacology , Gene Expression Regulation, Neoplastic/drug effects , Intercellular Adhesion Molecule-1/biosynthesis , Neoplasm Proteins/metabolism , Prostatic Neoplasms/metabolism , Up-Regulation/drug effects , Vasodilator Agents/pharmacology , Cell Line, Tumor , Gene Expression Regulation, Neoplastic/genetics , Humans , Intercellular Adhesion Molecule-1/genetics , Male , Neoplasm Proteins/genetics , Prostatic Neoplasms/genetics , Prostatic Neoplasms/pathology , Signal Transduction/drug effects , Signal Transduction/genetics , Up-Regulation/geneticsABSTRACT
BACKGROUND: Prostate cancer is the most commonly diagnosed malignancy in men and shows a predilection for metastasis to the bone. Bradykinin (BK) is an inflammatory mediator, and shows elevated levels in regions of severe injury and inflammatory diseases. The aim of this study was to investigate whether Bradykinin is associated with migration of prostate cancer cells. METHODS: Cancer cells migration activity was examined using the Transwell assay. The c-Src and PKCδ phosphorylation was examined by using Western blot method. The qPCR was used to examine the mRNA expression of metalloproteinase. A transient transfection protocol was used to examine NF-κB activity. RESULTS: We found that bradykinin increased the chemomigration and the expression of MMP-9 of human prostate cancer cells. Bradykinin-mediated chemomigration and metalloproteinase expression was attenuated by PKCδ inhibitor (rottlerin), PKCδ siRNA, c-Src inhibitor (PP2) and c-Src mutant. Activations of PKCδ, c-Src and NF-κB pathways after bradykinin treatment was demonstrated, and bradykinin-induced expression of metalloproteinase and chemomigration activity was inhibited by the specific inhibitor and mutant of PKCδ, c-Src, and NF-κB cascades. CONCLUSIONS: This study showed for the first time that the bradykinin mediates migration of human prostate cancer cells. One of the mechanisms underlying bradykinin directed migration was transcriptional up-regulation of MMP-9 and activation of B2 receptor, PKCδ, c-Src, and NF-κB pathways.
Subject(s)
Adenocarcinoma/drug therapy , Bradykinin/pharmacology , Prostatic Neoplasms/drug therapy , Protein Kinase C-delta/metabolism , Receptor, Bradykinin B2/metabolism , Signal Transduction/drug effects , src-Family Kinases/metabolism , Acetophenones/pharmacology , Adenocarcinoma/metabolism , Benzopyrans/pharmacology , Cell Line, Tumor , Cell Movement/drug effects , Humans , Male , Matrix Metalloproteinase 9/metabolism , NF-kappa B/metabolism , Phosphorylation , Prostatic Neoplasms/metabolism , Protein Kinase C-delta/antagonists & inhibitors , RNA, Small Interfering/pharmacologyABSTRACT
Prostate cancer is the most commonly diagnosed malignancy in men and shows a predilection for metastasis to distant organs. Leptin, an adipocyte-derived cytokine that is closely associated with obesity, has recently been shown to be involved in carcinogenesis and cancer progression. The aim of this study was to investigate whether leptin is associated with the motility of prostate cancer cells. We found that leptin increased the migration of human prostate cancer cells and expression of αvß3 integrin on these cells. Leptin-mediated migration and increased integrin expression were attenuated by OBRl receptor antisense oligonucleotide (ODN). Activation of insulin receptor substrate (IRS-1), phosphatidylinositol 3-kinase (PI3K), Akt, and NF-κB pathways after leptin treatment was demonstrated. Furthermore, leptin-induced integrin expression and migration activity were inhibited by specific inhibitors; small interfering RNAs (siRNAs); and mutants of the IRS-1, PI3K, Akt, and NF-κB cascades. Therefore, this study shows that leptin stimulates the migration of human prostate cancer cells, one of the mechanisms underlying leptin-directed migration was transcriptional up-regulation of αvß3 integrin expression through the OBR1/IRS-1/PI3K/Akt/NF-κB signal transduction pathway.
