Table 1

Effects of podophyllotoxin (PPT) and picropodophyllin (PPP) on cell viability and basal insulin-like growth factor (IGF)-1R tyrosine phosphorylation in various cell lines

Cell viability and IGF-1R phosphorylation of intact cells were determined after 48 h and 1 h, respectively. The concentration required for IC50 is shown. Each value is based on at least three different experiments. The experiments were repeated three to eight times with similar results.

OriginCell linePPT (μm)PPP (μm)
Viability IC50 (48 h)pIGF-1R IC50 (1 h)Viability IC50 (48 h)pIGF-1R IC50 (1 h)
MelanomaFM 55<0.05<0.050.06<0.05
SK-MEL-28<0.05<0.05<0.05<0.05
SK-MEL-5<0.05<0.05ndand
C8161<0.05<0.05<0.05<0.05
DFB0.05<0.050.05<0.05
DFW0.05<0.050.05<0.05
AA<0.05<0.05<0.05nd
SarcomaRD-ES<0.05<0.050.08<0.05
Breast carcinomaMCF 70.25<0.050.05<0.05
Prostate carcinomaPC30.1nd0.1nd
HepatomaHepG2>15b>15b
Embryonic mouse fibroblastsP6<0.05<0.05<0.05<0.05
R->15b>15b
  • a nd, not determined.

  • b No IGF-1R activity detected.