Correlation between cell enlargement and nucleic acid and protein content of hela cells in unbalanced growth produced by inhibitors of DNA synthesis

HeLa cells in monolayer cultures were treated with the following inhibitors of DNA synthesis: mitomycin C, nitrogen mustard, fluorodeoxyuridine, hydroxyurea, arabinofuranosylcytosine and high concentrations of thymidine. The concentration of each inhibitor used was, in most cases, just sufficient to arrest cell multiplication and all produced unbalanced growth in the sense that the synthesis of RNA and protein were only partially inhibited while DNA synthesis stopped. This resulted in approximately 100% increases in RNA and protein content per cell in 48 hours and, since cell volume also increased by 100% during this time, the concentration of RNA and protein per unit cell volume remained constant. It was concluded that cell protein content may be used as an accurate index of variation in cell size in HeLa cells treated with inhibitors of DNA synthesis.