Mammalian cells were grown as multicellular aggregates (spheroids) in an effort to determine the signaling events required for two cellular transformations states; primary foreskin fibroblasts (HFF-2) and glioblastoma cancer (T98G) cells, to survive at room temperature under oxygen and nutrient-deprived conditions for extended periods of time (2 weeks) and subsequently grown out from the arrested state as adherent monolayers. HFF-2 cells were cultured in DMEM supplemented with 15% fetal bovine serum and 5% carbon dioxide humidified air at 37 degrees C. T98G cells were cultured in EMEM with 10% FBS, 5% non-essential amino acids and 5% carbon dioxide humidified air at 37 degreesC. Monolayers were grown in T-185 flasks to 60% confluency then split into T-185 flasks coated with a 1% agarose mix in a 2:1 media/water ratio. Cells were suspended in 30 ml of supplemented media and grown for 4 days in order to form multicellular spheroids as described previously by our group (J. Cell. Physiol., 206  526-536; see GSE1364 and GSE1455 for similar experiments with HEK293 cells). The suspension was removed from the flasks and centrifuged (1500 x g, 2 min) and the media removed. The pellet was returned to the flasks and then placed in vacuum bags (Dri-shield 2000 moisture barrier bag from Surmount Inc., USA; Cat. number 70068), which were sealed immediately under vacuum (Deni Magic Vac, Champion model; Keystone Manufacturing, USA). Vacuum-sealed flasks were stored for 2 weeks (in the dark) at room temperature. Recovery was initiated by removing the flask from the bag and resuspending the spheroids in supplemented media and placing the flasks in a 5% CO2/humidified air incubator maintained at 37 degreesC. Timepoints for transcriptional analysis were monolayer (control), 4 day growth spheroids, 2 week stored spheroids and 7 day growth back to monolayers.