Comparative functional analysis of DPYD variants of potential clinical relevance to dihydropyrimidine dehydrogenase activity.
Comparative functional analysis of DPYD variants of potential clinical relevance to dihydropyrimidine dehydrogenase activity.
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DOI：
10.1158/0008-5472.can-13-2482
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发表时间：
2014-05-01
期刊：
影响因子：
11.2
通讯作者：
Diasio RB
中科院分区：
文献类型：
--
作者：
Offer SM;Fossum CC;Wegner NJ;Stuflesser AJ;Butterfield GL;Diasio RB
二氢嘧啶脱氢酶（DPD）是尿嘧啶分解代谢途径的起始酶和限速酶，对常用抗癌药物5-氟尿嘧啶（5-FU）的失活至关重要。DPD损伤导致5-FU暴露增加，进而增加5-FU对细胞毒性核苷酸的拮抗作用，导致更严重的临床不良反应。已经描述了编码DPD（DPYD）的基因内的许多变体，尽管只有少数变体已被证明降低DPD酶活性。为了鉴定改变酶功能的DPYD变体，我们在同基因哺乳动物系统中表达了80种蛋白质编码变体，并测量了它们将5-FU转化为二氢氟尿嘧啶（DPD催化剂的产物）的能力。M166 V、E828 K、K861 R和P1023 T变体表现出比野生型DPD显著更高的酶活性（分别为120%，P=0.025; 116%，P=0.049; 130%，P=0.0077; 138%，P=0.048）。与5-FU毒性的临床相关性研究一致，D949 V取代使酶活性降低41%（P=0.0031）。另外30种变体的酶活性也显著降低，其中19种具有<25%的活性。这30种变异体中没有一种先前在临床相关性研究中报告与5-FU毒性相关，这些研究主要在欧洲血统人群中进行。利用公开的基因型数据库，我们证实了这些变异在欧洲人群中的罕见性，但表明它们在其他人群中的检测频率相当高。这些数据强烈表明，检测报告的缺陷DPYD变异可以显着提高5-FU敏感性的预测性基因检测，特别是在非欧洲血统的个体中。
Dihydropyrimidine dehydrogenase (DPD) is the initial and rate limiting enzyme of the uracil catabolic pathway, being critically important for inactivation of the commonly prescribed anti-cancer drug 5-fluorouracil (5-FU). DPD impairment leads to increased exposure to 5-FU and, in turn, increased anabolism of 5-FU to cytotoxic nucleotides, resulting in more severe clinical adverse effects. Numerous variants within the gene coding for DPD, DPYD, have been described, although only a few have been demonstrated to reduce DPD enzyme activity. To identify DPYD variants that alter enzyme function, we expressed 80 protein-coding variants in an isogenic mammalian system and measured their capacities to convert 5-FU to dihydrofluorouracil, the product of DPD catabolism. The M166V, E828K, K861R, and P1023T variants exhibited significantly higher enzyme activity than wildtype DPD (120%, P=0.025; 116%, P=0.049; 130%, P=0.0077; 138%, P=0.048; respectively). Consistent with clinical association studies of 5-FU toxicity, the D949V substitution reduced enzyme activity by 41% (P=0.0031). Enzyme activity was also significantly reduced for 30 additional variants, 19 of which had <25% activity. None of those 30 variants have been previously reported to associate with 5-FU toxicity in clinical association studies, which have been conducted primarily in populations of European ancestry. Using publicly available genotype databases, we confirmed the rarity of these variants in European populations, but showed that they are detected at appreciable frequencies in other populations. These data strongly suggest that testing for the reported deficient DPYD variations could dramatically improve predictive genetic tests for 5-FU sensitivity, especially in individuals of non-European descent.