Analogous to the colon carcinoma cell lines, SipA markedly enhanced the cytotoxic activity of P-gp substrates, such doxorubicin and vinblastine in breast adenocarcinoma (MCF-7) and human bladder carcinoma (UM-UC-3) in vitro (Supplementary Fig. 5). Here, PGP is linked to colon carcinoma.