Validation of the cell line LS180 as a model for study of the gastrointestinal toxicity of mycophenolic acid.

1. Gastrointestinal (GI) intolerability is a concern for drugs such as mycophenolic acid (MPA) and drug metabolism may play a role. Few in vitro models exist that allow for the preclinical evaluation of a potential role of drug metabolism in intestinal drug toxicity. Thus, we sought to develop an in vitro model based on the human colon adenocarcinoma cell line LS180 to investigate MPA's negative effects on intestinal cells. 2. Stability of expression of key enzymes of MPA metabolism (UGT1A7, UGT1A9, UGT1A10, UGT2B7, CYP3A4 and CYP3A5), transporters (OATP1B1, OATP1B3, OATP2B1, MRP1, MRP2 and MDR1) and the nuclear receptor PXR over 12 passages in combination with guanosine supplementation to counter MPA's antiproliferative effects (determined by western blot analysis and proliferation assays, respectively) was established. 3. Expression of LS180 key enzymes remained stable over passages 47-59 and MPA-induced growth inhibition was circumvented by exogenous guanosine over a period of three days. MPA was not cytotoxic at concentrations up to 250 μM, a concentration that intestinal cells adjacent to the dissolving capsule or tablet are exposed to. 4. We concluded that LS180 cells are suitable to study the potential association between MPA metabolism and its negative effects on intestinal cells.