Gap junctional communication in cultured human lung carcinoma cells

Animal tumor models have demonstrated a close correlation between gap junct ional, intercellular communication (GJIC) and tumor metastasis. To examine GJIC levels in human lung carcinoma cells, a novel technique was developed: cells were grown on a glass slide, half of which was coated with electrica lly conductive, optically transparent, indium-tin oxide. An electric pulse which opens transient pores on the plasma membrane was applied in the prese nce of the fluorescent dye, Lucifer yellow, causing the dye's penetration i nto the cells growing on the conductive part of the slide. The migration of the dye through gap junctions to the non-electroporated cells growing on t he non-conductive area was then observed microscopically under fluorescence illumination. The results show that this is a rapid, precise and highly re producible assay for GJIC assessment in lines established from lung carcino mas or freshly explanted lung tumor cells. Out of 17 established lines only two had extensive junctional communication, while out of 16 fresh tumor sp ecimens none displayed GJIC. On the other hand, fibroblasts isolated from t he same tumors had extensive junctional permeability. The examination of GJ IC in a large number of samples could establish a correlation between GJIC and metastasis which might have prognostic value. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.