No abstract

The selective modulation of ABC efflux pumps overexpressed in multidrug resistant cancers (MDR) and attendant resensitization to chemotherapeutic agents represents a promising strategy for treating cancer. We have synthesized four novel pentacyclic Strychnos alkaloids alstolucines B (2), F (3), A (5), and N-demethylalstogucine (4), in addition to known Strychnos alkaloid echitamidine (16), and evaluated compounds 1–3, 5 in biochemical assays with ABCC10 and P-gp. Alstolucines B (2) and F (3) inhibited ABCC10 ATPase activity at 12.5 μM without affecting P-gp function; moreover, they resensitized ABCC10-transfected cell lines to paclitaxel at 10 μM. Altogether, the alstolucines represent promising lead candidates in the development of modulators of ABCC10 for MDR cancers overexpressing this pump.