A SIMPLE METHOD FOR PRODUCING DIFFERENT GROWTH FRACTIONS IN VITRO FOR USE IN ANTI-CANCER DRUG STUDIES

Abstract
A simple technique was used experimentally to produce in vitro Chinese hamster ovary [CHO] cells with growth fractions ranging from 0-100%. Known numbers of exponentially growing and plateau-phase tissue culture cells were mixed in various proportions to yield the desired final growth fraction. Cells attach to the culture flask surface within 1 h of mixing. Treatment at that time with the nitrosourea compounds, CCNU [1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea] and MeCCNU [1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea] [antineoplastic drugs], resulted in differential drug survival sensitivies that were dependent upon the growth fraction of the population treated.