This is a pre-copyedited, author-produced PDF of an article accepted for publication in Journal of Antimicrobial Chemotherapy following peer review. The version of record Mukhopadhya, I, Murray, GI, Berry, S, Thomson, J, Frank, B, Gwozdz, G, Ekeruche-Makinde, J, Shattock, R, Kelly, C, Iannelli, F, Pozzi, G, El-Omar, EMA-G, Hold, GL & Hijazi, K 2016, 'Drug Transporter Gene Expression in Human Colorectal Tissue and Cell Lines: Modulation with Antiretrovirals for Microbicide Optimization' Journal of Antimicrobial Chemotherapy, vol 71, no. 2, pp. 372-386. is available online at: http://jac.oxfordjournals.org/content/71/2/372