Cortactin underpins CD44-promoted invasion and adhesion of breast cancer cells to bone marrow endothelial cells

• Published in: Oncogene Vol. 25; no. 45; pp. 6079 - 6091
• Main Authors: HILL, A, MCFARLANE, S, WAUGH, D. J. J, MULLIGAN, K, GILLESPIE, H, DRAFFIN, J. E, TRIMBLE, A, OUHTIT, A, JOHNSTON, P. G, HARKIN, D. P, MCCORMICK, D
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing 05.10.2006; Nature Publishing Group
• Subjects: Base Sequence; Biological and medical sciences; Blotting, Western; Bone cancer; Bone marrow; Bone Marrow - pathology; Breast cancer; Breast Neoplasms - pathology; c-Myc protein; CD44 antigen; Cell adhesion & migration; Cell Adhesion - physiology; Cell Line, Tumor; Cell physiology; Cell transformation and carcinogenesis. Action of oncogenes and antioncogenes; Cells; Cortactin - physiology; DNA Primers; Endothelial cells; Endothelium - pathology; Fundamental and applied biological sciences. Psychology; Gene expression; Gynecology. Andrology. Obstetrics; Humans; Hyaluronan Receptors - physiology; Hyaluronic acid; Immunoblotting; Immunohistochemistry; Invasiveness; Mammary gland diseases; Medical sciences; Metastases; Metastasis; Molecular and cellular biology; Myc protein; Neoplasm Invasiveness; NF-κB protein; RNA-mediated interference; Signal Transduction; Transcription; Transcription, Genetic; Tumor cell lines; Tumors; Mammary gland diseases; Endothelial cell; invasion; Bone marrow; Breast cancer; Malignant tumor; Metastasis; Adhesion; Carcinogenesis; CD44; cortactin
• ISSN: 0950-9232; 1476-5594
• DOI: 10.1038/sj.onc.1209628

Using a validated tetracycline (tet)-regulated MCF7-founder (MCF7F) expression system to modulate expression of CD44 standard form (CD44s), we report the functional importance of CD44s and that of a novel transcriptional target of hyaluronan (HA)/CD44s signaling, EMS1/cortactin, in underpinning breast cancer metastasis. In functional experiments, tet-regulated induction of CD44s potentiated the migration and invasion of MCF7F cells through HA-supplemented Matrigel. EMS1/cortactin was identified by expression profiling as a novel transcriptional target of HA/CD44 signaling, an association validated by quantitative PCR and immunoblotting experiments in a range of breast cancer cell lines. The mechanistic basis underpinning CD44-promoted transcription of EMS1/cortactin was shown to be dependent upon a NFkappaB mechanism, since pharmacological inhibition of IkappaKinase-2 or suppression of p65 Rel A expression attenuated CD44-induced increases in cortactin mRNA transcript levels. Overexpression of a c-myc tagged murine cortactin construct in the weakly invasive, CD44-deficient MCF7F and T47D cells potentiated their invasion. Furthermore, the functional importance of cortactin to CD44s-promoted metastasis was demonstrated by selective suppression of cortactin in CD44-expressing MCF7F-B5 and MDA-MB-231 breast cancer cells using RNAi, which was shown to result in attenuated CD44-promoted invasion and CD44-promoted adhesion to bone marrow endothelial cells (BMECs).