TY - JOUR T1 - Colorectal cancer specific cytochrome P450 2W1 (CYP2W1): intracellular localization, glycosylation, and catalytic activity JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.110.067652 SP - mol.110.067652 AU - Alvin Gomez AU - Jana Nekvindova AU - Sandra Travica AU - Mi-young Lee AU - Inger Johansson AU - David Edler AU - Souren Mkrtchian AU - Magnus Ingelman-Sundberg Y1 - 2010/08/30 UR - http://molpharm.aspetjournals.org/content/early/2010/08/30/mol.110.067652.abstract N2 - Cytochrome P4502W1 (CYP2W1) is expressed at high levels in colorectal cancer cells. Moreover, we have previously shown that a higher tumor expression is associated with less survival. In this study we characterize posttranslational modification, inverted ER topology and catalytic activity of CYP2W1. The analysis of colorectal normal and cancer tissues and CYP2W1 overexpressing HEK-293 cells showed that a fraction of CYP2W1 is modified by N-glycosylation. Bioinformatic analysis identified Asn177 as the only possible glycosylation site of CYP2W1, which was supported by the inability of an Asn177Ala mutant to be glycosylated in HEK-293 cells. Analysis of the membrane topology indicated that unlike other P450s, CYP2W1 in HEK-293 transfected cells and in non-transfected Caco2TC7 and HepG2 cells is oriented towards the lumen of the ER, a topology making CYP2W1 available to the ER glycosylation machinery. Immunofluorescence microscopy and cell surface biotinylation experiments revealed about 8 % of the CYP2W1 on the cell surface. Despite the reverse orientation of CYP2W1 in the ER membrane, apparently making functional interactions with NADPH-cytochrome P450 reductase impossible, CYP2W1 in HEK-293 cells was active in the metabolism of indoline substrates and was able to activate aflatoxin B1 into cytotoxic products. The study identifies for the first time a cytochrome P450 enzyme with a luminal ER orientation and still retaining catalytic activity. Collectively these results suggest the possibility to utilize CYP2W1 as a drug target in the treatment of colon cancer using antibodies and/or specific CYP2W1 activated prodrugs. ER -