RT Journal Article SR Electronic T1 Overcoming P-glycoprotein mediated drug resistance with noscapine derivatives JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP dmd.118.083188 DO 10.1124/dmd.118.083188 A1 Divya Muthiah A1 Georgia K Henshaw A1 Aaron J DeBono A1 Ben Capuano A1 Peter Scammells A1 Richard Callaghan YR 2018 UL http://dmd.aspetjournals.org/content/early/2018/11/26/dmd.118.083188.abstract AB The antitussive agent noscapine has previously been shown to inhibit the proliferation of cancer cells by disruption of tubulin dynamics. However, the efficacy of several anticancer drugs that inhibit tublin dynamics (vinca alkaloids and taxanes) is reduced by the multidrug resistance phenotype. In particular, these compounds are substrates for P-glycoprotein (P-gp) mediated extrusion from cells. Consequently, the anti-proliferative activity of noscapine, and a series of derivatives, was measured in drug sensitive and drug resistant cells that over-express P-gp. None of the noscapine derivatives displayed lower potency in cells over-expressing P-gp; thereby suggesting a lack of interaction with this pump. However, the cellular efflux of a fluorescent substrate by P-gp was potently inhibited by noscapine and the majority of derivatives. Further investigation with purified, reconstituted P-gp demonstrated that inhibition of P-gp function was due to direct interaction of noscapine derivatives with the transporter. Moreover, co-administration of vinblastine with two of the noscapine derivatives displayed synergistic inhibition of proliferation, even in P-gp expressing resistant cell lines. Therefore, noscapine derivatives offer a dual benefit of overcoming the significant impact of P-gp in conferring multidrug resistance and synergy with tubulin-disrupting anticancer drugs.