Arachidonic Acid Activates Mitogen-activated Protein (MAP) Kinase-activated Protein Kinase 2 and Mediates Adhesion of a Human Breast Carcinoma Cell Line to Collagen Type IV through a p38 MAP Kinase-dependent Pathway

Abstract

Adhesion of metastatic human mammary carcinoma MDA-MB-435 cells to the basement membrane protein collagen type IV can be activated by treatment with arachidonic acid. We initially observed that this arachidonic acid-mediated adhesion was inhibited by the tyrosine kinase inhibitor genistein. Therefore, we examined the role of the mitogen-activated protein (MAP) kinase family tyrosine phosphorylation-regulated pathways in arachidonic acid-stimulated cell adhesion. Arachidonic acid stimulated the phosphorylation of p38, the activation of MAP kinase-activated protein kinase 2 (MAPKAPK2, a downstream substrate of p38), and the phosphorylation of heat shock protein 27 (a downstream substrate of MAP kinase-activated protein kinase 2). Treatment with the p38 inhibitor PD169316 completely and specifically inhibited arachidonic acid-mediated cell adhesion to collagen type IV. p38 activity was specifically associated with arachidonic acid-stimulated adhesion; this was demonstrated by the observation that 12-O-tetradecanoylphorbol 13-acetate-activated cell adhesion was not blocked by inhibiting p38 activity. Extracellular signal-regulated protein kinases (ERKs) 1 and 2 were also activated by arachidonic acid; however, cell adhesion to collagen type IV was not highly sensitive to PD98059, an inhibitor of MAP kinase kinase/ERK kinase 1 (MEK1) that blocks activation of the ERKs. c-Jun NH 2 -terminal kinase was not activated by arachidonic acid treatment of these cells. Together, these data suggest a novel role for p38 MAP kinase in regulating adhesion of breast cancer cells to collagen type IV.Cell adhesion to extracellular matrix plays a major role in a variety of biological processes, such as embryonic development (1-3), wound healing (4, 5), cell proliferation (6 -8), and disease pathogenesis (9, 10). Among these processes is tumor cell metastasis, during which neoplastic cells interact with other tumor cells, normal endothelial cells, and the extracellular matrix. These interactions are sensitive to regulation by the local microenvironment and are dependent upon cell surface adhesion molecules (11-16). We are interested in identifying factors that influence the adhesive properties of human tumor cells and that in doing so alter the metastatic potential of these cells.There are several families of adhesion molecules, the function of which can affect metastasis, including cadherins, selectins, the CD44 group, the immunoglobulin superfamily, and integrins (16,17). Integrins are heterodimeric, transmembrane cell surface glycoproteins that mediate adhesion to the extracellular matrix in a highly regulated manner and are linked to signal transduction pathways within the cell (18 -20). Because of the profound effect that integrins and their interactions with the extracellular matrix have on the biology of the cell, the proteins and second messengers that regulate these signal transduction pathways play critical roles in the behavior of both normal and transformed cells (6,8,(21)(22)(23).The MAP 1 kinase signaling pathways are ubi...

Dysregulation of phosphatidylinositol 3‐kinase and downstream effectors in human breast cancer

“…MAPKAPK2 has been shown to mediate adhesion to basement membrane collagen in response to arachidonic acid. 30 Although there have been no reports on the expression of MAPKAPK2 in any human cancers, a MAPKAPK 2 homologue designated 3pk (chromosome 3p kinase) was originally cloned from a tumor suppressor region located on chromosome 3 in small cell lung cancers. 31 In order to examine p38 MAPK enzymatic activity, samples were immunoprecipitated and the phosphotransferase activity determined using MBP as the substrate.…”

p38 MAP kinase modulates Smad-dependent changes in human prostate cell adhesion

“…Prior reports implicate p38 MAP kinase in mediating cell adhesion-associated pathways (Paine et al, 2000). In addition, prior reports also show that p38 MAP kinase is activated by TGFb (Hanafusa et al, 1999;Yamamoto et al, 2001;Bakin et al, 2002;Wang et al, 2002;Yu et al, 2002;Ungefroren et al, 2003).…”

Cross-talk between Cytosolic Phospholipase A2α (cPLA2α) and Secretory Phospholipase A2 (sPLA2) in Hydrogen Peroxide-induced Arachidonic Acid Release in Murine Mesangial Cells

“…The possibility of direct cPLA 2 ␣ phosphorylation by PKC continues to be an important subject for further investigation. It has been reported that iPLA 2 (87,88) and p38 (89,90) are involved in stimulus-coupled AA release in some cell types. Our data indicate, however, that both pathways are not involved in H 2 O 2 -induced AA release in murine MC.…”