Functional Characterization of 12 Dihydropyrimidinase Allelic Variants in Japanese Individuals for the Prediction of 5-Fluorouracil Treatment-Related Toxicity

Eiji Hishinuma, Yoko Narita, Evelyn Marie Gutierrez Rico, Akiko Ueda, Kai Obuchi, Yoshikazu Tanaka, Sakae Saito, Shu Tadaka, Kengo Kinoshita, Masamitsu Maekawa, Nariyasu Mano, Tomoki Nakayoshi, Akifumi Oda, Noriyasu Hirasawa, Masahiro Hiratsuka

研究成果: ジャーナルへの寄稿学術論文査読

3 被引用数 (Scopus)

抄録

The drug 5-fluorouracil (5-FU) is the first-choice chemotherapeutic agent against advanced-stage cancers. However, 10% to 30% of treated patients experience grade 3 to 4 toxicity. The deficiency of dihydropyrimidinase (DHPase), which catalyzes the second step of the 5-FU degradation pathway, is correlated with the risk of developing toxicity. Thus, genetic polymorphisms within DPYS, the DHPase-encoding gene, could potentially serve as predictors of severe 5-FU-related toxicity. We identified 12 novel DPYS variants in 3554 Japanese individuals, but the effects of these mutations on function remain unknown. In the current study, we performed in vitro enzymatic analyses of the 12 newly identified DHPase variants. Dihydrouracil or dihydro-5-FU hydrolytic ring-opening kinetic parameters, Km and Vmax, and intrinsic clearance (CLint 5 Vmax/Km) of the wild-type DHPase and eight variants were measured. Five of these variants (R118Q, H295R, T418I, Y448H, and T513A) showed significantly reduced CLint compared with that in the wild-type. The parameters for the remaining four variants (V59F, D81H, T136M, and R490H) could not be determined as dihydrouracil and dihydro-5-FU hydrolytic ring-opening activity was undetectable. We also determined DHPase variant protein stability using cycloheximide and bortezomib. The mechanism underlying the observed changes in the kinetic parameters was clarified using blue-native polyacrylamide gel electrophoresis and three-dimensional structural modeling. The results suggested that the decrease or loss of DHPase enzymatic activity was due to reduced stability and oligomerization of DHPase variant proteins. Our findings support the use of DPYS polymorphisms as novel pharmacogenomic markers for predicting severe 5-FU-related toxicity in the Japanese population.

本文言語英語
ページ(範囲)165-173
ページ数9
ジャーナルDrug Metabolism and Disposition
51
2
DOI
出版ステータス出版済み - 2023 2月 1

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