title: Cortactin underpins CD44-promoted invasion and adhesion of breast cancer cells to bone marrow endothelial cells.
abstract: 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).
authors.affiliation: Centre for Cancer Research and Cell Biology, Queens University Belfast, Belfast City Hospital, Belfast, Northern Ireland.
authors.forename: A
authors.initials: A
authors.lastname: Hill
authors.forename: S
authors.initials: S
authors.lastname: McFarlane
authors.forename: K
authors.initials: K
authors.lastname: Mulligan
authors.forename: H
authors.initials: H
authors.lastname: Gillespie
authors.forename: J E
authors.initials: JE
authors.lastname: Draffin
authors.forename: A
authors.initials: A
authors.lastname: Trimble
authors.forename: A
authors.initials: A
authors.lastname: Ouhtit
authors.forename: P G
authors.initials: PG
authors.lastname: Johnston
authors.forename: D P
authors.initials: DP
authors.lastname: Harkin
authors.forename: D
authors.initials: D
authors.lastname: McCormick
authors.forename: D J J
authors.initials: DJ
authors.lastname: Waugh
mesh_terms: D001483:Base Sequence; D015153:Blotting, Western; D001853:Bone Marrow / Q000473:pathology*; D001943:Breast Neoplasms / Q000473:pathology*; D002448:Cell Adhesion / Q000502:physiology*; D045744:Cell Line, Tumor; D051356:Cortactin / Q000502:physiology*; D017931:DNA Primers; D004727:Endothelium / Q000473:pathology*; D006801:Humans; D018960:Hyaluronan Receptors / Q000502:physiology*; D007150:Immunohistochemistry; D009361:Neoplasm Invasiveness; D015398:Signal Transduction; D014158:Transcription, Genetic
chemical_list: D051356:Cortactin; D017931:DNA Primers; D018960:Hyaluronan Receptors