ABCB1 and cancer: As shown in Table 3, HS-173 at the maximum sub-toxic concentration of 100 nM had no significant effect on ABCB1-mediated resistance to well-established anticancer drug substrates of ABCB1 (colchicine, vincristine, or paclitaxel) [63] in ABCB1-overexpressing KB-V1 cancer cells.