EFFECTS OF GAMMA-RADIATION ON THE OM431 HUMAN OCULAR MELANOMA CELL-LINE

In order to determine the dose responsiveness to radiation of ocular m elanoma, we conducted an in vitro dose-response study on a monolayer c ell culture using a clonogenic assay. The effects on cell survival wer e determined relative to unirradiated controls. A human epithelioid oc ular melanoma cell line, OM431, was maintained in tissue culture and s erial dilutions of viable cells were prated in flasks, allowed to sett le and attach for 48 h, and subsequently irradiated with 1-10 Gy in si ngle fractions. After 2 weeks, the number of reproducing clones (formi ng colonies with greater than 32 cells or five generations) were count ed. The surviving fractions of cells were plotted on a cell survival c urve using the linear quadratic model. The survival curve showed a lar ge initial shoulder followed by an exponential decline in growth. Our data suggest that the OM431 ocular melanoma cell line responds to irra diation in a manner similar to other melanoma cell lines and is relati vely radioresistant especially at lower doses.