Effect of tumor-conditioned medium on intercellular communication and proliferation of Balb/c 3T3 cells

The possible role of tumor cell-derived factors in the regulation of gap ju nctional intercellular communication and proliferation of fibroblasts was s tudied in a model system of Balb/c 3T3 cells growing in tumor conditioned m edium by Lucifer Yellow CH dye-transfer and BrdU incorporation assays. Six to 24 h incubation of Balb/c 3T3 cells in a medium conditioned by WiDr aden ocarcinoma cells enhanced the gap junctional communication between the cell s by 25-40% as revealed by intercellular transfer of a fluorescent dye Luci fer Yellow CH. Simultaneously the cell proliferation rates were examined an d found to be reduced by 23% at 24 h treatment. Since adenocarcinoma cells are known to secrete different growth factor-like polypeptides into their c onditioned medium, we suppose that tumors that produce these molecules migh t alter their host environment through the enhancement of cell-cell communi cation thereby facilitating the exchange of modulatory factors. (C) 2000 El sevier Science Ireland Ltd. All rights reserved.