Table 2.

Levels of target proteins, nucleoside transporter genes, and TFT nucleotide accumulation in H630 cells and the TFT-resistant variants H630-4TFT and H630-cTFT

Cell line
H630H630-4TFTH630-cTFT
TS
    FdUMP binding sites*0.52 ± 0.130.34 ± 0.080.77 ± 0.23
    TS activity: at 1 μmol/L dUMP0.53 ± 0.030.23 ± 0.080.56 ± 0.03
    TS activity: at 10 μmol/L dUMP1.93 ± 0.230.58 ± 0.141.89 ± 0.23
    TS protein expression (%)§100122.3 ± 21.288.7 ± 9.1
TK
    Total TK activity9.04 ± 1.090.57 ± 0.0621.28 ± 0.25
    TK1 activity2.96 ± 0.350.16 ± 0.014.07 ± 1.13
    TK protein expression (%)§100<5154 ± 28.6
TP
    TP activity18.96 ± 2.9316.76 ± 2.620.68 ± 2.72
Transporters
    hENT mRNA expression (%)10040 ± 846 ± 14
    hCNT mRNA expression (%)10093 ± 71,600 ± 265
TFT nucleotides (nmol/million cells)29.1 ± 3.26.8 ± 2.13.2 ± 1.4
sPLA2 IIA
    Intracellular (pg/million cells)41.2 ± 5.0>10,000>10,000
    Extracellular (pg/million cells)7.0 ± 0.9235.3 ± 25.1333.6 ± 16.8

NOTE: All values are means ± SEM of at least three experiments.

  • *FdUMP binding sites in fmol/mg protein.

  • Enzyme activities in nmol/hr/mg protein.

  • Significantly different compared to parental cells (P < 0.05).

  • §Relative density compared to H630.

  • Significantly different compared to parental cells (P < 0.01).

  • Values are given as a percentage in which H630 mRNA expression levels were set to 100%.