Study on DNA Metabolizing Enzymes as Molecular Theraputic Targets in Renal Cell Carcinoma

5-氟尿嘧啶（5-FU）是临床上用于治疗包括肾细胞癌（RCC）在内的各种癌症的抗癌化疗剂。5-FU抑制胸苷酸合成酶（TS）并阻断DNA合成。TS是DNA合成过程中催化脱氧尿苷一磷酸甲基化为脱氧胸苷一磷酸的关键酶。关于TS在RCC中的意义知之甚少。我们调查了68个RCC样本中的TS活性，并评估了TS活性水平与RCC分期/分级之间的关系。此外，TS活性在RCC中的预后意义进行了检查。用5-氟-2 ′-脱氧尿苷5 ′-单磷酸结合法测定了未固定的新鲜冰冻肾细胞癌和正常肾组织中TS活性水平，分析了原代培养肾细胞TS活性与5-FU敏感性的关系。采用MTT法检测原代培养的肾癌细胞系对5-FU的敏感性， ...更多信息 微培养四氮唑染料测定：TS的活性在RCC中比正常肾高约5倍。T3/4期肾细胞癌TS活性是T1/2期肾细胞癌的2.5倍。M1期肾癌TS活性是M0期肾癌的2.5倍。此外，TS活性在III/IV期RCC中比在I/II期RCC中高3倍。3级RCC中TS活性水平分别是1级和2级癌的3倍和2倍。透明细胞肾细胞癌TS活性是乳头状肾细胞癌的4倍。在5年随访中，TS活动低的患者比TS活动高的患者有更长的疾病特异性生存期。原代培养肾细胞癌细胞TS活性与其对5-FU的敏感性呈正相关，本研究首次证实肾细胞癌TS活性高于正常肾细胞，且TS活性水平与肾细胞癌的分期和分级有关。此外，肾癌TS活性越高，预后越差，对5-FU敏感性越高。这些结果表明，TS活性的水平可以作为一个预后参数和5-FU在RCC疗效的预测指标，和TS可能是一个分子治疗靶点在RCC。少

5-fluorouracil(5-FU) is an anticancer chemotherapeutic agent clinically used against various cancers including renal cell carcinoma(RCC). 5-FU inhibits thymidylate synthase(TS) and blocks DNA synthesis. TS is the key enzyme in the catalysis of the methylation from deoxyuridine monophosphate to deoxythymidine monophosphate in the DNA synthetic process. Little is known about the significance of TS in RCC. We investigated the activity of TS in 68 RCC samples and evaluated the association between the level of TS activity and the stage/grade of RCC. In addition, prognostic significance of TS activity in RCC was examined. The relationship between TS activity in primary cultured RCC cell lines and their sensitivity to 5-FU was also analyzed.The level of TS activity in non-fixed fresh frozen RCC and normal kidney specimens was determined biochemically by the 5-fluoro-2'-deoxyuridine 5'-monophosphate binding assay. The sensitivity of primary cultured RCC cell lines to 5-FU was assessed by the m … More icroculture tetrazolium dye assay.The activity of TS was approximately 5-fold higher in RCC compared to normal kidney. TS activity in T3/4 RCC was 2.5-fold higher than that in T1/2 RCC. TS activity in M1 RCC was 2.5-fold higher than that in M0 RCC. In addition, TS activity in Stage III/IV RCC was 3-fold higher than that in Stage I/II RCC. The levels of TS activity in Grade 3 RCC were 3-fold and 2-fold higher than that in Grade 1 and Grade 2 cancer, respectively. TS activity in clear cell RCC were 4-fold higher than that in papillary RCC. Patients with low TS activity had a longer disease-specific survival as compared to those with high activity in the 5-year follow-up. TS activity in primary cultured RCC cell lines positively correlated with their sensitivity to 5-FU.The present study is the first study to demonstrate that TS activity in RCC was higher than that in normal kidney, and that the level of TS activity correlated with both the progression of the stage and the increase of the grade of RCC. In addition, higher TS activity in RCC predicted worse prognosis and higher sensitivity to 5-FU. These results suggest that the level of TS activity may be used as both a prognostic parameter and a predictive indicator for 5-FU efficacy in RCC, and that TS may be a molecular therapeutic target in RCC. Less