The Roles of Integrins and Extracellular Matrix Proteins in the Insulin-like Growth Factor I-stimulated Chemotaxis of Human Breast Cancer Cells

doi:10.1074/jbc.271.5.2443

The Roles of Integrins and Extracellular Matrix Proteins in the Insulin-like Growth Factor I-stimulated Chemotaxis of Human Breast Cancer Cells (*)

Monica E. Doerr and
John I. Jones^(§)

From the Division of Endocrinology, Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, 27599-7170

^§To whom correspondence should be addressed:
Division of Endocrinology, CB #7170, University of North Carolina, Chapel Hill, NC 27599-7170
. Tel: 919-966-3338; Fax: 919-966-6025.

Abstract

The effects of insulin-like growth factor I (IGF-I) on the migration of two human breast cancer cell lines, MCF-7 and MDA-231, were examined using a modified Boyden chamber. 10 ng/ml was the optimal IGF-I concentration for stimulation of migration. The majority of IGF-I-stimulated migration in both cell types was due to chemotaxis. MCF-7 cells failed to migrate on membranes coated with gelatin or fibronectin and migrated only in small numbers on laminin. In contrast, when vitronectin- or type IV collagen-coated membranes were used, the MCF-7 cells migrated in large numbers specifically in response to IGF-I but not to 10% fetal calf serum, epidermal growth factor, fibroblast growth factor, or platelet derived growth factor-BB. An IGF-I receptor-blocking antibody inhibited IGF-I-stimulated migration in both cell types. In addition, a blocking antibody to the αvβ5 integrin (a vitronectin receptor) inhibited migration of MCF-7 cells in response to IGF-I through vitronectin but not through type IV collagen. Similarly, blocking antibodies specific for α2 and β1 integrins significantly inhibited migration of both cell types through type IV collagen-coated membranes but not through vitronectin-coated membranes. We conclude that: 1) IGF-I stimulates migration of these two cell types through the IGF-I receptor; 2) interaction of vitronectin with the αvβ5 integrin or collagen with the α2β1 integrin is necessary for the complete IGF-I response in MCF-7 cells, and 3) because migration represents an in vitro model for metastatic spread, integrins, extracellular matrix proteins, and IGF-I may play coordinated roles in the metastasis of breast cancer in vivo.

Footnotes

↵* This work was presented in part at the 77th Annual Endocrine Society Meeting in Washington, D.C., 6, 1995 and was supported by National Institutes of Health Grants DK 02024 (to J. I. J.) and DK 07129 (M. E. D.) and by the Lineberger Comprehensive Cancer Center, University of North Carolina. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

IGF-I

insulin-like growth factor I

EGF

epidermal growth factor

bFGF

basic fibroblast growth factor

PDGF-BB

platelet-derived growth factor-BB

DMEM

Dulbecco's modified Eagle's medium

BSA

bovine serum albumin

PBS

phosphate-buffered saline

HBS

Hepes-buffered saline.
- Received November 21, 1995.