Editors' ChoiceCell Biology

Do Cells "See" Each Other?

Science's STKE  12 Apr 2005:
Vol. 2005, Issue 279, pp. tw138
DOI: 10.1126/stke.2792005tw138

Investigation of a 3T3 cell variant (3T3x) that forms clusters on solid substrates led Albrecht-Buehler to make the intriguing proposal that mammalian cells are able to detect each other through light scattering. Noting that cells in the center of 3T3x aggregates had large numbers of lysosomes--which, along with other perinuclear organelles, are the main light-scattering regions of mammalian cells--Albrecht-Buehler allowed cells to ingest small latex and diamond particles, which markedly enhanced their light-scattering ability. In aggregates formed by these hyperscattering cells, the center cells were those that scattered the most light. When hyperscattering cells were mixed with particle-free 3T3x cells, dispersed into dishes, and observed with time-lapse photography, the hyperscattering cells--which initially settled randomly--moved toward each other and aggregated. When cells were cultured on adhesive strips surrounded by nonadhesive substrate (to constrain movement to a single dimension) so that the distance over which cells could be influenced to move together could be estimated, cells appeared to detect each other at distances substantially greater than one cell diameter. Moreover, the distance over which cells could influence each other's movement (Ra) increased in parallel with their ability to scatter near-infrared light. Irradiation at 600 nm (visible light) decreased Ra, whereas irradiation at 800 nm (near-infrared) increased it. The ability of cells to aggregate inside unlighted incubators suggested that aggregation signals involved light in the near-infrared range. Thus, the author proposed that cells are able to detect each other through scattered near-infrared light and to use this information to direct their movements.

G. Albrecht-Buehler, A long-range attraction between aggregating 3T3 cells mediated by near-infrared light scattering. Proc. Natl. Acad. Sci. U.S.A. 102, 5050-5055 (2005). [Abstract] [Full Text]