Abstract
Targeting P-glycoprotein (P-gp, ABCB1 transporter), which plays an essential role in multi-drug resistance (MDR) in cancers, with new cytotoxic agents is a promising strategy in cancer chemotherapy. In the current study, we report the synthesis of thirteen novel pyrimidopyrrolizine, pyrimidoindolizine, and diazepinopyrrolizine derivatives. The new compounds exhibited cytotoxic activities against MCF7, A2780 and HT29 cancer cell lines (IC50 = 0.02–19.58 μM) and MRC5 (IC50 = 0.17–20.57 μM). The six most active compounds (23b, 24a,b and, 31c-e) were evaluated for their MDR reversal activities in MCF7/ADR cells. Mechanistic study using real-time PCR revealed the ability of compound 31c to inhibit P-gp. In addition, compound 31c increased the accumulation of Rho123 inside MCF7/ADR cells in a dose-dependent manner compared to verapamil. Compound 31c arrested the cell cycle of MCF7 cells at the G1 phase. Compound 31c also caused a significant dose-dependent increase of early and late apoptotic events. Molecular docking analysis revealed a high binding affinity for compound 31c toward P-gp. Like zosuquidar, compound 31c displayed one hydrogen bond and several hydrophobic interactions with amino acids in P-gp. These results indicated that compound 31c represents a potential anticancer candidate with MDR reversal activity.
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•New pyrimidopyrrolizine/indolizine, and diazepinopyrrolizine derivatives were synthesized and evaluated for their cytotoxicity against MCF7, A2780, HT29 and MRC5 cells.•The MDR reversal activity of compounds 23b, 24a,b, 31c-e was investigated in MCF7/ADR cells.•Compounds 31c inhibited P-gp and increased the accumulation of Rho123 inside MCF7/ADR cells.•Compound 31c arrested cells at the G1 cell cycle phase and induced apoptosis in MCF7 cells.•The potential binding mode of compound 31c into P-gp was investigated in a molecular docking study.