Relationship between intercellular communication and radiosensitivity of human tumor xenografts.

Micro-electrode techniques permit the detection of electrical coupling between adjacent cells if they are connected by intercellular junctions (gap junctions). This technique was applied to four human tumors xenografted onto nude mice. In three of the tumors, which showed a 'contact resistance' after irradiation in vivo, electrical coupling could be established. No coupling was found in the other tumor, which did not exhibit contact resistance. These results are similar to those obtained recently with cultured spheroids of mammalian cell lines in which only the electrically coupled cell types developed contact resistance to ionizing radiation.