Inhibition by ganciclovir of cell growth and DNA synthesis of cells biochemically transformed with herpesvirus genetic information.

The ability of LM cells, thymidine kinase-deficient LM cells (LMTK-), and LMTK- cells transformed to the LMTK+ phenotype by herpes simplex virus type 1 genetic information (LH7 cells) to anabolize the acyclovir congener ganciclovir was examined. About 50-fold more ganciclovir triphosphate was produced by LH7 cells than by either LM or LMTK- cells. Growth inhibition studies indicated that 180 and 120 microM ganciclovir were required to achieve 50% growth inhibition of LM and LMTK- cells, respectively; only 0.07 microM ganciclovir was necessary to achieve 50% inhibition of LH7 cells. DNA synthesis in the transformed cells was significantly reduced by ganciclovir treatment, whereas ganciclovir had little effect on DNA synthesis in the nontransformed cells. Alkaline sucrose gradient sedimentation analysis of transformed cellular DNA indicated that LH7 DNA synthesized in the presence of ganciclovir chased into mature DNA. Both LM and LH7 DNA synthesized in the presence of ganciclovir exhibited a concentration-dependent reduction in the rate of elongation into mature DNA. Finally, [14C]ganciclovir was incorporated internally into the growing chains of LH7 cells.