Table 1

Cytotoxicity of antimitotic agents in drug-resistant cell lines that overexpress P-glycoprotein

Cell linesIC50 (nm)a
TaxolVBLEpoAEpoBDiscoEleu
J774.267 ± 7.0b6.0 ± 2.710.6 ± 2.00.4 ± 0.136 ± 5.5394.2 ± 5.8
J7-T3-1.618,000 ± 2,645767 ± 351170 ± 1412 ± 4.01,050 ± 70>5,000
Fold resistantc 268.7 127.816 30 29.2>12.7
SKOV32.0 ± 0.11.1 ± 0.110.3 ± 4.50.5 ± 0.099.7 ± 0.38.2 ± 3.8
SKVLB13,333 ± 1,1541,880.3 ± 347.5190 ± 149.5 ± 2.1575 ± 233>5,000
Fold resistantd6,666.51,709.418.519.059.3>609.8
  • a IC50, drug concentration that inhibits cell division by 50% after 72 h (J774.2 and J7-T3-1.6) or 6 days (SKOV3 and SKVLB). VBL, vinblastine; EpoA, epothilone A; EpoB, epothilone B; Disco, discodermolide; Eleu, eleutherobin.

  • b Mean ± SE.

  • c Ratio of IC50 for the resistant cell line (J7-T3-1.6) to that for sensitive cell line (J774.2) after 72 h.

  • d Ratio of IC50 for the resistant cell line (SKVLB) to that for sensitive cell line (SKOV3) after 6 days.