Response to chemotherapy of EMT6 spheroids as measured by growth delay and cell survival.

Multicellular tumour spheroids of the EMT6 mouse tumour line have been grown in a static (i.e. non-spinner) culture system to a mean spheroid diameter of 250 mum. Samples of spheroids were then exposed for 1 h to graded concentrations of various cytotoxic drugs, and the response assayed by both growth delay and survival of clonogenic cells. For nitrogen mustard (HN2), melphalan, BCNU, CCNU and cis-platinum, a considerable recovery in measured cell survival was seen if correlation between growth delay and cell survival (measured at 24 h) was observed for these 5 agents. For adriamycin, actinomycin D and 5-fluorouracil, no increase in measured cell survival was seen for a 24h delay in assay, and these agents produced longer growth delays for a given level of cell kill.