CONNEXIN TRANSFECTION INDUCES INVASIVE PROPERTIES IN HELA-CELLS

Gap-junctional coupling of tumor cells facilitates their invasion into normal tissue as was further investigated with connexin-transfected H eLa cells by an in vitro assay. Wild-type HeLa cells are coupling defi cient and did not show invasive properties when multicell spheroids we re confronted with precultured embryonic chicken heart fragments. Afte r transfection with cDNA of Cx31, Cx40, or Cx43, these cells were homo -typically coupled; Cx40- and Cx43-transfected HeLa cells also were he terotypically coupled with embryonic chicken heart cells in monolayer coculture. Transfected clones revealed invasive properties in the chic ken heart in vitro assay. However, the pattern of invasion differed be tween these transfectants: After 4 days Cx43-transfected HeLa cells we re found in the central part of heart spheroids; Cx40- and Cx31-transf ected HeLa cells, however, did not invade the central core but were de tected in the outer part of heart spheroids. We conclude that connexin expression supports invasion of tumor cells into normal tissue, but h eterotypic gap-junctional coupling is not required for this process. ( C) 1998 Academic Press.