Design, synthesis and biological evaluation of novel, simplified analogues of laulimalide: modification of the side chain

Synergistic Effects of Peloruside A and Laulimalide with Taxoid Site Drugs, but Not with Each Other, on Tubulin Assembly

“…Not surprisingly, in view of the drug-dependent tubulin critical concentrations in the literature (Gaitanos et al, 2004;Gapud et al, 2004;Paterson et al, 2005), we found that peloruside A was significantly less potent than laulimalide. In terms of relative activities, laulimalide A, as was noted previously (Pryor et al, 2002), has activity similar to paclitaxel, epothilone A, and eleutherobin, whereas the activity of peloruside A, as shown here, is most similar to that of sarcodictyins A and B and not very different from the less active laulimalide analog trans-desoxylaulimalide.…”

“…In general, in analog studies published to date, introduction of a single modification into laulimalide has resulted in moderate to severe reduction in cytotoxic activity, whereas introduction of more than one modification generally has yielded almost inert compounds (Pryor et al, 2002;Ahmed et al, 2003;Wender et al, 2003Wender et al, , 2006Gallagher et al, 2004Gallagher et al, , 2005Mooberry et al, 2004;Paterson et al, 2005). Important findings thus far: 1) if the epoxide moiety of laulimalide is replaced with a trans-olefin bond, activity is reduced 23-to 51-fold against MCF-7 (Pryor et al, 2002;Ahmed et al, 2003; see above), 11-fold against MaTu (Ahmed et al, 2003), and 19-to 21-fold against MDA-MB-435 breast cancer cells (Wender et al, 2003;Mooberry et al, 2004) [a larger loss of activity against MDA-MB-435 cells was reported by Gallagher et al (2004)]; 2) if the C-2/C-3 olefin bond is changed from cis to trans, activity is reduced 10-to 14-fold against MaTu and MCF-7 cells, respectively (Ahmed et al, 2003) [again, a larger loss of activity against MDA-MB-435 cells was reported by Gallagher et al (2004)]; 3) if the C-30 methyl substituent at C-11 is removed, activity is reduced 9-fold against MDA-MB-435 cells (Wender et al, 2006) and 15-fold against A2780 ovarian cancer cells ; 4) if the hydroxyl at C-20 is methylated or acetylated, activity is reduced 40-to 42-fold against MDA-MB-435 cells (Wender et al, 2003;Gallagher et al, 2004;Mooberry et al, 2004); 5) if the hydroxyl at C-15 is acetylated, activity is reduced 10-fold against MDA-MB-435 cells, with larger reductions with other ester groups (Gallagher et al, 2004); 6) if the C-15 hydroxyl group is methylated, activity is reduced over 400-fold against MDA-MB-435 cells (Gallagher et al, 2004); 7) if an alkyne bond is introduced between C-2 and C-3, activity is reduced over 400-fold against MDA-MB-435 cells ; 8) possibly, if the side chain is eliminated or modified, activity is substantially reduced ; and 9) possibly, if configuration is reversed at C-15, activity is substantially reduced (Gallagher et al, 2004).…”

“…Laulimalide has been examined in multiple human cancer cell lines by many workers, and it has yielded IC 50 values in the 2 to 11 nM range (Mooberry et al, 1999;Pryor et al, 2002;Ahmed et al, 2003;Gallagher et al, 2004;Paterson et al, 2005;Wender et al, 2006). The IC 50 values of peloruside A in human cancer cell lines range from 6 to 66 nM (Hood et al, 2001(Hood et al, , 2002Gaitanos et al, 2004), and thus it may be less active than laulimalide.…”

Mutations in the β-tubulin binding site for peloruside A confer resistance by targeting a cleft significant in side chain binding

“…Our recent efforts with laulimalide model building, 16 together with NMR data, 19 analog data, 20 and recent modeling results, 21 suggest an alternative binding mode. In this model peloruside A is reoriented by approximately 180 degrees, such that the side chain is buried in a cavity in the "back" of the binding site.…”

“…The reaction products were purified with Performa DTR gel filtration columns (Edge Bio) and analyzed on a 3130xl Genetic Analyzer (Applied Biosystems Inc.). The following primers were used for sequencing: ATC GTG CAC ATC CAG GCT GG (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29), ATC CAG GCT GGT CAA TG (19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) Sequence variation among cells was examined by cloning individual cells from Pel cell cultures, expanding the clonal cultures, and then isolating RNA and sequencing as described above. Cells were cloned by plating in 100 mm dishes at low density (and in…”