Inhibition of tolbutamide 4-methylhydroxylation by a series of non-steroidal anti-inflammatory drugs in V79-NH cells expressing human cytochrome P4502C10

Abstract

1. To study the role of cytochrome P4502C10 in the metabolism of the non-steroidal antiinflammatory drugs (NSAIDs) diclofenac, phenylbutazone, fenoprofen, ibuprofen, flurbiprofen, ketoprofen and naproxen, a cell line was developed stably expressing CYP2C10 cDNA. A retroviral vector construct, containing a human CYP2C10 cDNA, was transfected in V79-NH Chinese hamster lung cells by calcium phosphate co-precipitation. Sublines stably expressing human cytochrome P450 cDNA were established by selection with the neomycin analogue G418.

2. Enzymatic activity of CYP2C10 was detected by 4-methylhydroxylation of tolbutamide. This activity was inhibited to background levels by preincubation with the CYP2C9/10 inhibitor sulphaphenazole.

3. Preincubations with the NSAIDs ketoprofen, phenylbutazone, flu-biprofen and diclofenac (all 250 μM) caused a decrease in 4-methylhydroxylation of tolbutamide (500 μM), significantly different from control values (p < 0.05). Inhibition of this activity was not seen in preincubations with the NSAIDs fenoprofen, ibuprofen and naproxen (250 μM).

4. The V79-NH CYP2C10 cell line we have developed has been shown to be a useful tool to predict drug-drug interactions.