Internalization of the E-Cadherin/Catenin Complex and Scattering of Human Mammary Carcinoma Cells MCF-7/AZ after Treatment with Conditioned Medium from Human Skin Squamous Carcinoma Cells COLO 16

Cytokines and other paracrine or autocrine factors functionally modulate the invasion-suppressor and signal-transducing E-cadherin/catenin complex. We have used conditioned medium from human squamous carcinoma COLO 16 cells (CM COLO 16) as a source of such factors to modulate the E-cadherin/catenin complex in human breast carcinoma MCF-7 cells.CM COLO 16 induces scattering of MCF-7/AZ, but not of MCF-7/6 cells on tissue culture plastic substratum, and reduces aggregation of MCF-7/AZ cells in suspension. Insulin-like growth factor I counteracts this reduction of aggregation. Confocal laser scanning microscopy of immunocytochemical stainings shows loss of the honeycomb pattern of E-cadherin, α-catenin and β-catenin, and internalization of those elements. Cell surface biotinylation shows a decrease in membrane-bound E-cadherin. Immunoprecip-itation and cell fractionation show that the composition of the complex is maintained. Interleukin-1, interleukin-6, granulocyte-monocyte colony stimulating factor, stem ...