Interindividual Variability of Carboxymethylenebutenolidase Homolog, a Novel Olmesartan Medoxomil Hydrolase, in the Human Liver and Intestine

Abstract

Olmesartan medoxomil (OM) is a prodrug-type angiotensin II type 1 receptor antagonist. OM is rapidly converted into its active metabolite olmesartan by multiple hydrolases in humans, and we recently identified carboxymethylenebutenolidase homolog (CMBL) as one of the OM bioactivating hydrolases. In the present study, we further investigated the interindividual variability of mRNA and protein expression of CMBL and OM-hydrolase activity using 40 individual human liver and 30 intestinal specimens. In the intestinal samples, OM-hydrolase activity strongly correlated with the CMBL protein expression, clearly indicating that CMBL is a major contributor to the prodrug bioactivation in human intestine. The protein and activity were highly distributed in the proximal region (duodenum and jejunum) and decreased to the distal region of the intestine. Although there was high interindividual variability (16-fold) in both the protein and activity in the intestinal segments from the duodenum to colon, the interindividual variability in the duodenum and jejunum was relatively small (3.0-and 2.4-fold, respectively). In the liver samples, the interindividual variability in the protein and activity was 4.1-and 6.8-fold, respectively. No sex differences in the protein and activity were shown in the human liver or intestine. A genetically engineered Y155C mutant of CMBL, which was caused by a single nucleotide polymorphism rs35489000, showed significantly lower OM-hydrolase activity than the wild-type protein although no minor allele was genotyped in the 40 individual liver specimens.

Identifying Methylation Pattern and Genes Associated with Breast Cancer Subtypes

“…The next predicted gene is CMBL , which encodes a specific cysteine hydrolase of the dienelactone hydrolase family and normally has high expression in liver cytosol but not in breast tissues [43,44]. In 2014, an early study on proteasome function in breast cancer confirmed that cysteine hydrolase has an abnormal expression level in certain breast cancer subtypes, and this finding corresponds with our prediction [45].…”

Chemoproteomic Identification of Serine Hydrolase RBBP9 as a Valacyclovir-Activating Enzyme

“…In general, other poorly studied metabolic enzymes stand to benefit similarly from PAE identification via cABPP as most well-characterized metabolic enzymes are amenable to the standard suite of mechanism-based inhibitors used in reaction phenotyping studies. The recent discovery of the sparsely studied hydrolase CMBL as a PAE for the antihypertensive prodrug olmesartan medoxomil , illustrates that numerous enzymes with unique and exploitable specificities remain unidentified. We hope that the experiments herein represent the first study of many in which researchers use cABPP for PAE identification.…”

Different Hydrolases Involved in Bioactivation of Prodrug-Type Angiotensin Receptor Blockers: Carboxymethylenebutenolidase and Carboxylesterase 1

“…For olmesartan measurement, the Captiva filtrate was mixed with 200 ml of 50% methanol containing 1% formic acid, and was analyzed by liquid chromatography-tandem mass spectrometry consisting of a Prominence LC-20A system (Shimadzu, Kyoto, Japan) and an API3200 (Applied Biosystems/ MDS SCIEX, Foster City, CA) as previously reported (Ishizuka et al, 2013). For candesartan and azilsartan measurements, the filtrate was directly analyzed by liquid chromatography-tandem mass spectrometry consisting of a Prominence CBM-20A system (Shimadzu) and an API4000 (Applied Biosystems/ MDS SCIEX).…”