kallidin and Breast-Neoplasms

The sera of patients with breast cancer have higher levels of des[Arg(9)]bradykinin, a kinin B1 receptor (B1R) agonist, than that from healthy individuals. Stimulation of breast cancer cells with the analog Lys-des[Arg(9)]bradykinin causes release of metalloproteinases-2 and -9 and increases cell proliferation. We examined the possibility that breast cancer cells, in addition to B1R, express the kinin-forming protease true tissue kallikrein (KLK1) and the endogenous proteins termed kininogens from which kinins are enzymatically released. Furthermore, we investigated whether stimulation of breast cancer cells with a B1R agonist would modify the cellular levels of KLK6, KLK10 and KLK11, three kallikrein-related peptidases with a still poorly-understood biological role in breast cancer. We found that breast cancer cells expressed KLK1 and kininogens, and that stimulation of estrogen-sensitive breast cancer cells with the B1R agonist produced down-regulation of KLK10 (a protease associated with growth suppression) but up-regulation of KLK11 and KLK6 (peptidases related to increased cell proliferation and invasiveness, respectively). Furthermore, we showed that the B1R agonist acts as a functional stimulus for the secretion of KLK1 and KLK6, an event relevant for kinin production and cell invasion, respectively.

Topics: Bradykinin; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Female; Humans; Kallidin; Kallikreins; Kininogens; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; MCF-7 Cells; Neoplasm Invasiveness; Receptor, Bradykinin B1; RNA Interference; RNA, Small Interfering; Serine Endopeptidases; Tissue Kallikreins; Up-Regulation

In this paper the signal transduction pathways evoked by bradykinin (BK) in MCF-7 breast cancer cells were investigated. BK activation of the B(2) receptor provoked: (a) the phosphorylation of the extracellular signal-regulated kinases 1 and 2 (ERK1/2); (b) the translocation from the cytosol to the membrane of the conventional protein kinase C-alpha (PKC-alpha) and novel PKC-delta and PKC-epsilon; (c) the phosphorylation of protein kinase B (PKB/ Akt); (d) the proliferation of MCF-7 cells. The BK-induced ERK1/2 phosphorylation was completely blocked by PD98059 (an inhibitor of the mitogen-activated protein kinase kinase (MAPKK or MEK)) and by LY294002 (an inhibitor of phosphoinositide 3-kinase (PI3K)), and was reduced by GF109203X (an inhibitor of both novel and conventional PKCs); Gö6976, a conventional PKCs inhibitor, did not have any effect. The BK-induced phosphorylation of PKB/Akt was blocked by LY294002 but not by PD98059. Furthermore, LY294002 inhibited the BK-provoked translocation of PKC-delta and PKC-epsilon suggesting that PI3K may be upstream to PKCs. Finally, the proliferative effects of BK were blocked by PD98059, GF109203X and LY294002. These observations demonstrate that BK acts as a proliferative agent in MCF-7 cells activating intracellular pathways involving novel PKC-delta/-epsilon, PKB/Akt and ERK1/2.

Topics: Analysis of Variance; Biological Transport; Bradykinin; Bradykinin B1 Receptor Antagonists; Bradykinin B2 Receptor Antagonists; Breast Neoplasms; Cell Line, Tumor; Cell Membrane; Cell Proliferation; Chromones; Cytosol; Dose-Response Relationship, Drug; Estrenes; Female; Flavonoids; Humans; Immunoblotting; Indoles; Kallidin; Maleimides; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Morpholines; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Protein Kinase C; Protein Kinase C beta; Protein Kinase C-delta; Protein Kinase C-epsilon; Pyrrolidinones; Stimulation, Chemical; Tetrahydroisoquinolines