Integrin-mediated laminin-1 adhesion upregulates CXCR4 and IL-8 expression in pancreatic cancer cells.
BACKGROUND
We have shown recently that alpha(2)beta(1) integrin-mediated type I collagen adhesion promotes a more malignant phenotype in pancreatic cancer cell lines than other extracellular matrix (ECM) proteins. MiaPaCa-2 cells, by contrast, do not express collagen-binding integrins, but are metastatic in our orthotopic mouse model and migrate maximally on laminin-1 (Ln-1). It has also been shown that CXCR4 and IL-8 expression correlates directly with metastasis in pancreatic cancer in vivo. We therefore examined the potential of the ECM to regulate CXCR4 and IL-8 expression in pancreatic cancer cells.


METHODS
We cultured 8 pancreatic cancer cell lines on fibronectin (Fn), types I and IV collagen, Ln-1 and vitronectin (Vn), and examined cell lysates for CXCR4 by immunoblotting and media for IL-8 by ELISA. We also conducted cell migration assays with stromal-derived factor-1 (SDF-1) as the chemoattractant to examine integrin-binding specificity and CXCR4 function.


RESULTS
All cell lines expressed CXCR4 protein. MiaPaCa-2 cell growth on Ln-1 increased significantly CXCR4 and IL-8 expression relative to other ECM proteins. Migration inhibition studies showed that both the alpha(6)beta(1) and alpha(3)beta(1) integrins mediate MiaPaCa-2 migration on Ln-1. Growth studies showed further that CXCR4 expression on Ln-1 was mediated by the alpha(6)beta(1) integrin whereas IL-8 expression was mediated by both the alpha(6)beta(1) and alpha(3)beta(1) integrins. The expression of functional CXCR4 was also shown in migration assays, where SDF-1 significantly increased pancreatic cancer cell chemotaxis on Ln-1.


CONCLUSIONS
These data indicate that integrin-mediated Ln-1 adhesion upregulates CXCR4 and IL-8 expression and may play a mechanistic role in pancreatic cancer metastases.
Grzesiak
John J
JJ
Veterans Affairs San Diego Healthcare System and the Departments of Surgery, San Diego, Calif.
Smith
Kathy C
KC
Burton
Douglas W
DW
Deftos
Leonard J
LJ
Bouvet
Michael
M
D002448:Cell Adhesion; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000494:pharmacology; D002633:Chemotaxis / Q000187:drug effects; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006801:Humans; D039201:Integrin alpha3beta1 / Q000378:metabolism; D039121:Integrin alpha6beta1 / Q000378:metabolism; D016023:Integrins / Q000378:metabolism*; D016209:Interleukin-8 / Q000378:metabolism*; D007797:Laminin / Q000494:pharmacology*; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D019718:Receptors, CXCR4 / Q000378:metabolism*; D015854:Up-Regulation
C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D016326:Extracellular Matrix Proteins; D039201:Integrin alpha3beta1; D039121:Integrin alpha6beta1; D016023:Integrins; D016209:Interleukin-8; D007797:Laminin; D019718:Receptors, CXCR4; C121346:laminin 1