Synthesis, anticancer evaluation and pharmacokinetic study of novel 10-O-phenyl ethers of dihydroartemisinin

Twenty hybrid compounds, tethering dihydroartemisinin (DHA) with diaryl-pyrazoline/diaryl-pyrazole through ether linkage, were synthesized based on hybridization strategy and assessed for their anticancer activity. The representative compound 6f exhibited significantly elevated antiproliferative activity compared with DHA against a panel of cancer cell lines. Unexpected sensitivity of 6f in Adriamycin-resistant MCF-7 cells (MCF-7/Adr) inspired subsequent research on anticancer activity of these DHA derivatives against breast cancer cell lines. All the novel compounds exhibited potent activity in three breast cancer cells including MDA-MB-231, MCF-7 and MCF-7/Adr. Most of them exerted almost 10-fold higher potency in MCF-7/Adr than in MCF-7 and MDA-MB-231 cells. Compound 5f, the most potent compound against MCF-7/Adr (GI₅₀ = 18 nM), was used for mechanism research which revealed that compound 5f arrested MCF-7 and MCF-7/Adr cells in G0/G1 phase with decreased levels of cyclin D1 and increased levels of p27. Preliminary pharmacokinetic properties of 5f and 6f were investigated in rats after a single intravenous administration. The high sensitivity of MCF-7/Adr indicates that these compounds have potential to be developed as therapeutic agents to treat drug-resistant cancer.