Detection of genes differentially expressed in radioresistant and radiosensitive tumors before and after irradiation

Nu61, a radiation-resistant human tumor xenograft, was selected from a parental radiosensitive tumor SCC-61 by eight serial cycles of passage in athymic nude mice and in vivo irradiation. Obtained tumors were profiled using Affymetrix U133A arrays. Most abundant gene pattern associated with radioresistant phenotype was presented by IFN-inducible, Stat1-dependent pathway Keywords: Pair-wise comparison of radiosensitive vs radioresistant tumors; time course of irradation response Obtained tumors were established as xenografts in nude mice. RNA were purified from each xenograft, normalized by concentration and used for hybridization with each array. Three arrays were used for each group (un-treated nu61 and SCC61 and irradiated nu61 and SCC61 5 and 24 hours post-IR). Each group contained from 5 animals; tumors were randomized by size and three tumors from each group were used for profiling