title: Epithelial-stromal interactions in human breast cancer: effects on adhesion, plasma membrane fluidity and migration speed and directness.
abstract: Interactions occurring between malignant cells and the stromal microenvironment heavily influence tumor progression. We investigated whether this cross-talk affects some molecular and functional aspects specifically correlated with the invasive phenotype of breast tumor cells (i.e. adhesion molecule expression, membrane fluidity, migration) by co-culturing mammary cancer cells exhibiting different degrees of metastatic potential (MDA-MB-231>MCF-7) with fibroblasts isolated from breast healthy skin (normal fibroblasts, NFs) or from breast tumor stroma (cancer-associated fibroblasts, CAFs) in 2D or 3D (nodules) cultures. Confocal immunofluorescence analysis of the epithelial adhesion molecule E-cadherin on frozen nodule sections demonstrated that NFs and CAFs, respectively, induced or inhibited its expression in MCF-7 cells. An increase in the mesenchymal adhesion protein N-cadherin was observed in CAFs, but not in NFs, as a result of the interaction with both kinds of cancer cells. CAFs, in turn, promoted N-cadherin up-regulation in MDA-MB-231 cells and its de novo expression in MCF-7 cells. Beyond promotion of "cadherin switching", another sign of the CAF-triggered epithelial-mesenchymal transition (EMT) was the induction of vimentin expression in MCF-7 cells. Plasma membrane labeling of monolayer cultures with the fluorescent probe Laurdan showed an enhancement of the membrane fluidity in cancer cells co-cultured with NFs or CAFs. An increase in lipid packing density of fibroblast membranes was promoted by MCF-7 cells. Time-lapsed cell tracking analysis of mammary cancer cells co-cultured with NFs or CAFs revealed an enhancement of tumor cell migration velocity, even with a marked increase in the directness induced by CAFs.Our results demonstrate a reciprocal influence of mammary cancer and fibroblasts on various adhesiveness/invasiveness features. Notably, CAFs' ability to promote EMT, reduction of cell adhesion, increase in membrane fluidity, and migration velocity and directness in mammary cancer cells can be viewed as an overall progression- and invasion-promoting effect.
authors.affiliation: Istituto di Istologia ed Embriologia, Università Cattolica del Sacro Cuore, Roma, Italia.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Angelucci
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Maulucci
authors.forename: Gina
authors.initials: G
authors.lastname: Lama
authors.forename: Gabriella
authors.initials: G
authors.lastname: Proietti
authors.forename: Anna
authors.initials: A
authors.lastname: Colabianchi
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Papi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Maiorana
authors.forename: Marco
authors.initials: M
authors.lastname: De Spirito
authors.forename: Alessandra
authors.initials: A
authors.lastname: Micera
authors.forename: Omar Bijorn
authors.initials: OB
authors.lastname: Balzamino
authors.forename: Alba
authors.initials: A
authors.lastname: Di Leone
authors.forename: Riccardo
authors.initials: R
authors.lastname: Masetti
authors.forename: Gigliola
authors.initials: G
authors.lastname: Sica
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D006801:Humans; D017154:Stromal Cells / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
chemical_list: D015820:Cadherins