Figure 3.

Pel^r lines are only resistant to peloruside A/laulimalide binding site drugs. The IC₅₀ for a number of drugs was determined as in Figure 1 for parental and Pel^r lines. Fold resistance, calculated as (Pel IC₅₀)/(parental IC₅₀), is presented with error bars representing standard deviation. Resistance was measured for peloruside A (Pel) and five other microtubule stabilizing drugs: laulimalide (Laul), paclitaxel (Ptx), epothilone A (EpoA), dictyostatin (Dictyo) and discodermolide (Disco). In addition four microtubule destabilizing drugs were tested: combretastatin A4 (CSA4), nocodazole (Noc), vinblastine (Vbl) and D24851. Two non-microtubule-targeting drugs were also included: etoposide (VP16), and Romedepsin (or Depsipeptide FK228 = Depsi). Results for all drugs are grouped by Pel^r line. The Table below the graph gives the parental cell IC₅₀ and the number or replicates.