Functional characterization of 21 allelic variants of dihydropyrimidinase

Hishinuma, Eiji; Akai, Fumika; Narita, Yoko; Maekawa, Masamitsu; Yamaguchi, Hiroaki; Mano, Nariyasu; Oda, Akifumi; Hirasawa, Noriyasu; Hiratsuka, Masahiro

doi:10.1016/j.bcp.2017.06.121

Cited by 12 publications

(22 citation statements)

References 24 publications

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“…Conversely, our present data have indicated that no patients who are heterozygous for DPYS p.Arg181Trp developed a severe adverse event following FP treatment. The kinetic parameters of the corresponding mutant enzyme were assessed in a previous report and no markedly reduced activity relative to wild‐type DHP was evident 25 . This variant may have protective effects against the development of FP‐related toxicity in vivo, but the mechanism is unknown.…”

Section: Discussionmentioning

confidence: 98%

Impact of DPYD, DPYS, and UPB1 gene variations on severe drug‐related toxicity in patients with cancer

et al. 2020

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Cancer treatment with a fluoropyrimidine (FP) is often accompanied by severe toxicity that may be dependent on the activity of catalytic enzymes encoded by the DPYD, DPYS, and UPB1 genes. Genotype‐guided dose individualization of FP therapy has been proposed in western countries, but our knowledge of the relevant genetic variants in East Asian populations is presently limited. To investigate the association between these genetic variations and FP‐related high toxicity in a Japanese population, we obtained blood samples from 301 patients who received this chemotherapy and sequenced the coding exons and flanking intron regions of their DPYD, DPYS, and UPB1 genes. In total, 24 single nucleotide variants (15 in DPYD, 7 in DPYS and 2 in UPB1) were identified including 3 novel variants in DPYD and 1 novel variant in DPYS. We did not find a significant association between FP‐related high toxicity and each of these individual variants, although a certain trend toward significance was observed for p.Arg181Trp and p.Gln334Arg in DPYS (P = .0813 and .087). When we focused on 7 DPYD rare variants (p.Ser199Asn, p.IIe245Phe, p.Thr305Lys, p.Glu386Ter, p.Ser556Arg, p.Ala571Asp, p.Trp621Cys) which have an allele frequency of less than 0.01% in the Japanese population and are predicted to be loss‐of‐function mutations by in silico analysis, the group of patients who were heterozygous carriers of at least one these rare variants showed a strong association with FP‐related high toxicity (P = .003). Although the availability of screening of these rare loss‐of‐function variants is still unknown, our data provide useful information that may help to alleviate FP‐related toxicity in Japanese patients with cancer.

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Section: Discussionmentioning

confidence: 98%

Impact of DPYD, DPYS, and UPB1 gene variations on severe drug‐related toxicity in patients with cancer

et al. 2020

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“…Hamajima et al and Thomas et al reported that six variants (L7V, T68R, Q334R, W360R, G435R, and R490C) showed lower activities than wild-type DHP in COS-7 and RKO cells expression systems [17,82]. We have characterized 21 DHP variants and wild-type DHP expressed in 293FT cells using UH 2 and FUH 2 as substrates [83]. Among these, 13 variants (N16K, T68R, M70T, D81G, G278D, R302Q, L337P, W360R, S379R, G435R, R465X, R475X, and R490C) demonstrated no enzymatic activity, and five variants (W117R, Q334R, T343A, V364M, and R412M) showed significantly lower CL int values than wild-type DHP.…”

Section: Dihydropyrimidinase (Dhp)mentioning

confidence: 94%

“…DHP activity is exerted by the interaction of the C-terminus with the dynamic loop of the neighboring subunit [89][90][91]. We have performed immunoblotting assays of native proteins following blue native polyacrylamide gel electrophoresis and showed that oligomer formation is very important for DHP activity [83]. In the reduced or null-activity variants, the ability of DHP to form oligomers was reduced.…”

Section: Dihydropyrimidinase (Dhp)mentioning

confidence: 99%

In Vitro Assessment of Fluoropyrimidine-Metabolizing Enzymes: Dihydropyrimidine Dehydrogenase, Dihydropyrimidinase, and β-Ureidopropionase

Hishinuma

Rico

Hiratsuka

2020

JCM

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Fluoropyrimidine drugs (FPs), including 5-fluorouracil, tegafur, capecitabine, and doxifluridine, are among the most widely used anticancer agents in the treatment of solid tumors. However, severe toxicity occurs in approximately 30% of patients following FP administration, emphasizing the importance of predicting the risk of acute toxicity before treatment. Three metabolic enzymes, dihydropyrimidine dehydrogenase (DPD), dihydropyrimidinase (DHP), and β-ureidopropionase (β-UP), degrade FPs; hence, deficiencies in these enzymes, arising from genetic polymorphisms, are involved in severe FP-related toxicity, although the effect of these polymorphisms on in vivo enzymatic activity has not been clarified. Furthermore, the clinical usefulness of current methods for predicting in vivo activity, such as pyrimidine concentrations in blood or urine, is unknown. In vitro tests have been established as advantageous for predicting the in vivo activity of enzyme variants. This is due to several studies that evaluated FP activities after enzyme metabolism using transient expression systems in Escherichia coli or mammalian cells; however, there are no comparative reports of these results. Thus, in this review, we summarized the results of in vitro analyses involving DPD, DHP, and β-UP in an attempt to encourage further comparative studies using these drug types and to aid in the elucidation of their underlying mechanisms.

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“…In this process, Dihydropyrimidine Dehydrogenase (DPD), Dihydropyrimidinase and β-ureidopropionase are involved in the first, second and the third steps respectively. At first, Thymine and Uracil are converted to 5,6-dihydrothymine and 5,6-dihydrouracil, followed by the next step in which the hydrolytic ring opening of the Dihydropyrimidines are catalyzed and finally in the last step, β-aminoisobutyric acid and β-alanine are resulted from the alterations of N-Carbamyl-β-aminoisobutyric acid and N-Carbamyl-β-alanine [3][4][5]. In contrast to DPD, which is expressed in all tissues, DHP and β-ureidopropionase are solely expressed in kidney and liver [6].…”

Section: Introductionmentioning

confidence: 99%

A novel stop-gain mutation in DPYS gene causing Dihidropyrimidinase deficiency, a case report

et al. 2020

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Background: Dihidropyrimidinase (DHP) deficiency is an inherited inborn error of pyrimidine metabolism with a variable clinical presentation and even asymptomatic subjects. Dihydropyrimidinase is encoded by the DPYS gene, thus pathogenic mutations in this gene can cause DHP deficiency. To date, several variations in the DPYS gene have been reported but only 23 of them have been confirmed to be pathogenic. Therefore, the biochemical, clinical and genetic aspects of this disease are still unclear. Case presentation: Here, we report a 22-year-old woman with DHP deficiency. To identify the genetic cause of DHP deficiency in this patient, Whole Exome Sequencing (WES) was performed, which revealed a novel homozygote stop gain mutation (NM_001385: Exon 9, c.1501 A > T, p.K501X) in the DPYS gene. Sanger sequencing was carried out on proband and other family members in order to confirm the identified mutation. According to the homozygote genotype of the patient and heterozygote genotype of her parents, the autosomal recessive pattern of inheritance was confirmed. In addition, bioinformatics analysis of the identified variant using Mutation Taster and T-Coffee Multiple Sequence Alignment showed the pathogenicity of mutation. Moreover, mRNA expression level of DPYS gene in the proband's liver biopsy showed about 6-fold reduction compared to control, which strongly suggested the pathogenicity of the identified mutation. Conclusions: This study identified a novel pathogenic stop gain mutation in DPYS gene in a DHP deficient patient. Our findings can improve the knowledge about the genetic basis of the disease and also provide information for accurate genetic counseling for the families at risk of these types of disorders.

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Functional characterization of 21 allelic variants of dihydropyrimidinase

Cited by 12 publications

References 24 publications

Impact of DPYD, DPYS, and UPB1 gene variations on severe drug‐related toxicity in patients with cancer

Impact of DPYD, DPYS, and UPB1 gene variations on severe drug‐related toxicity in patients with cancer

In Vitro Assessment of Fluoropyrimidine-Metabolizing Enzymes: Dihydropyrimidine Dehydrogenase, Dihydropyrimidinase, and β-Ureidopropionase

A novel stop-gain mutation in DPYS gene causing Dihidropyrimidinase deficiency, a case report

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