The dysfunction of homologous and/or heterologous gap junctional intercellular communication (GJIC) has been implicated in tumorigenesis of many kinds of cells. Here we have characterized GJIC and the expression of connexins in six @entity1 @entity2 cell lines and normal lung fibroblasts ( @entity15263 ). Compared with @entity15263 , all the @entity189 cells showed reduced or little homologous GJIC. They expressed remarkably reduced connexin(Cx)43 mRNA and variable levels of @entity28292 mRNA, but neither @entity495 nor @entity28292 protein could be detected. However, using a preloading assay, transfer of @entity5384 was observed between donor @entity15263 cells and first order neighboring recipient @entity5 cells (recipient cells in 1000-fold excess). Transfer from @entity5 to @entity15263 cells under the same conditions was not seen, although increasing the ratio of donor @entity5 cells to recipient @entity15263 cells and plating the cells at low density did reveal weak transfer from @entity5 cells to @entity15263 . Transfection of @entity495 into giant cell @entity189 PG cells increased homologous communication and eliminated the rectifying behavior of heterologous communication. This indicates that the apparent rectification of dye transfer between normal and @entity5 cells was a product of low rates of heterologous transfer linked to (i) rapid dilution of the dye to below detectable limits through a very well coupled cell population ( @entity5 to @entity15263 ) and (ii) concentration of dye in immediate neighbors in a poorly coupled cell population ( @entity15263 to @entity5 cells). These results suggest that the coupling levels may need to exceed a certain threshold to allow propagation of signals over a sufficient distance to affect behavior of a cell population. We propose that the relative rates of heterologous and homologous coupling of cell populations and the 'pool size' of shared metabolites in @entity5 cells and the surrounding normal tissue are likely to be very important in the regulation of their growth.

Effective asymmetry in gap junctional intercellular communication between populations of @entity1 normal lung fibroblasts and XXXX cells.

@entity1 :: ('9606', 'Species') :: ['human'] @entity495 :: ('2697', 'Gene') :: ['Cx43'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor'] @entity2 :: ('MESH:D008175', 'Disease') :: ['lung carcinoma'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinoma'] @entity28292 :: ('10052', 'Gene') :: ['Cx45'] @entity5384 :: ('MESH:C007740', 'Chemical') :: ['calcein'] @entity15263 :: ('3131', 'Gene') :: ['HLF']
@entity2 :: (MESH:D008175,Disease) :: ['lung carcinoma']
