The antiproliferative activity of MDS against the CA-4-resistant cell line HT-29 (colon adenocarcinoma) in the absence or the presence of 10 μM verapamil, a non-selective Pgp/MDR1 inhibitor, was measured 72 h post-treatment by a colorimetric method (Supplementary Table S1). The gene discussed is PGP; the disease is colon adenocarcinoma.