胸苷磷酸化酶表达与结直肠癌关系研究进展

胸苷磷酸化酶(thymidine phosphorylase, TP)是嘧啶核苷合成与分解过程中的一个关键酶。目前认为TP与血小板源性内皮细胞生长因子(platelet-derived endothelial cell growth factor, PD-ECGF)具有同源性, 其诱导血管形成和抗凋亡的作用与结直肠癌的生长、转移密切相关。同时TP也是使5'-脱氧氟尿苷(5'-deoxy-5-fluorouridine, 5'-DFUR)等(5-fluorouracil, 5-FU)前体药物转化为5-FU的关键酶, 其活性与结直肠癌细胞对氟尿嘧啶类药物的敏感性及靶向治疗密切相关。因TP在肿瘤的生长、转移、治疗和预后方面均有重要作用, 阐明其表达机制具有重要意义。本文将对近年TP在结直肠癌中的表达与肿瘤血管新生及与激活5'-DFUR发挥细胞毒作用、治疗结直肠癌的研究进展进行综述。      

结直肠癌患者手术前后胸苷酸磷酸化酶(TP)的表达及临床意义

目的:研究结直肠癌组织和血清中胸苷磷酸化酶(thymidine phosphorylase TP)表达与病理及生物特性之间的关系。方法:对50例结直肠癌标本、20例正常结直肠黏膜标本及18例结直肠良性病变组织进行免疫组化S-P法检测,测定TP表达情况;ELISA法测定结直肠癌患者术前、术后血清TP水平及20例健康志愿者血清TP水平。结果:结直肠癌组织中胸苷磷酸化酶表达的阳性率显著高于正常结直肠黏膜、结直肠良性病变(P<0.05);有淋巴结转移的结直肠癌组TP表达阳性率高于无淋巴结转移组(P<0.05);结直肠癌组血清TP水平较健康组为高,差别具有统计学意义(P<0.05);DukesA-B期和DukesC-D期患者之间血清TP水平比较差别具有统计学意义(P<0.05)。术前和术后结直肠癌患者血清TP水平差别具有统计学意义(P<0.05)。结论:结直肠癌Dukes分期较晚及有淋巴结转移者,其瘤组织中TP表达的阳性率高;血清胸苷磷酸化酶的水平与患者的肿瘤病理分期有关,分期越晚表达水平越高;胸苷磷酸化酶在组织中的表达与其血清的水平呈正相关性,血清胸苷磷酸化酶的水平可以反应其组织中的表达水平。     

结直肠癌组织中胸苷酸磷酸化酶的表达及其临床意义

背景与目的：血管生成已被公认是与肿瘤的生长和侵袭有关,近年研究表明胸苷酸磷酸化酶(thymidine phosphorylase,TP)不仅参与肿瘤新生血管形成,而且可增强5-氟尿嘧啶前药的化疗敏感性,但其在结直肠癌中的作用以及对预后的影响尚未得出一致的结论。本研究检测TP在人结直肠癌组织中的表达水平,并探讨其临床意义。方法：以西安交通大学第一医院行根治术且随访满5年的70例结直肠癌患者的库存组织标本为材料,采用免疫组织化学方法检测其TP表达水平。结果：TP表达主要见于肿瘤细胞胞浆之中,TP阳性表达患者40例,占57．14%。TP在不同Dukes’分期和不同病理组织学分级组织中的表达水平具有显著性差异(P=0．007和P=0．002)。Kaplan-Meier生存率分析提示,TP阳性表达者5年生存率为33．33％,而TP阴性表达者则为73．33％(P=0．000),结果提示TP阳性表达患者的预后较阴性表达者差。结论：TP表达可作为判断结直肠癌患者预后的参考指标之一。     

结直肠癌患者手术前后胸苷酸磷酸化酶（TP）的表达及临床意义

目的：研究结直肠癌组织和血清中胸苷磷酸化酶（thymidine phosphorylase TP）表达与病理及生物特性之间的关系。方法：对50例结直肠癌标本、20例正常结直肠黏膜标本及18例结直肠良性病变组织进行免疫组化S—P法检测,测定TP表达情况;ELISA法测定结直肠癌患者术前、术后血清TP水平及20例健康志愿者血清TP水平。结果：结直肠癌组织中胸苷磷酸化酶表达的阳性率显著高于正常结直肠黏膜、结直肠良性病变（P〈0．05）;有淋巴结转移的结直肠癌组TP表达阳性率高于无淋巴结转移组（P〈0．05）;结直肠癌组血清TP水平较健康组为高,差别具有统计学意义（P〈0．05）;DukesA—B期和DukesC—D期患者之间血清TP水平比较差别具有统计学意义（P〈0．05）。术前和术后结直肠癌患者血清,TP水平差别具有统计学意义（P〈0．05）。结论：结直肠癌Dukes分期较晚及有淋巴结转移者,其瘤组织中TP表达的阳性率高;血清胸苷磷酸化酶的水平与患者的肿瘤病理分期有关,分期越晚表达水平越高;胸苷磷酸化酶在组织中的表达与其血清的水平呈正相关性,血清胸苷磷酸化酶的水平可以反应其组织中的表达水平。     

胃癌组织中胸苷酸合成酶、胸苷磷酸化酶mRNA表达及其临床意义

背景与目的:化学治疗在胃癌治疗中扮演了重要的作用。通过肿瘤组织中某些基因表达的水平来选择化疗药物已成为今后化疗的方向。胸苷酸合成酶(TS)、胸苷磷酸化酶(TP)是氟尿嘧啶(5-FU)体内的关键代谢酶,其表达水平影响恶性肿瘤患者接受5-FU化疗后的预后。本研究探讨胃癌组织中TS、TP mRNA表达水平与预后的关系。方法:采用实时定量RT-PCR技术检测51例胃腺癌组织TS、TP mRNA表达水平。结果:胃癌组织TS、TP mRNA表达水平的中位数分别为0.94和21.20,TS高表达组和低表达组之间无瘤生存期和总生存期差异有显著性(P<0.05),TP高表达组和低表达组之间总生存期差异有显著性(P<0.05),但无瘤生存期之间差异无显著性(P>0.05)。TS、TP mRNA表达与年龄、性别、淋巴结转移、组织学分级及临床分期均无相关性(P>0.05)。结论:检测TS、TP mRNA表达水平对接受5-FU为基础治疗方案的胃癌患者的预后有很好的预测价值。     

结直肠癌患者胸苷酸磷酸化酶活性与XELOX新辅助化疗疗效的关系

目的 研究结直肠癌中胸苷酸磷酸化酶(TP)活性与XELOX新辅助化疗疗效之间的关系.方法 收集64例采用XELOX方案化疗的结直肠癌患者临床资料,根据TP酶活性不同分为TP高酶活性组(32例)和TP低酶活性组(32例),统计两组患者的化疗效果以及术后5年生存期.结果 TP高酶活性组患者化疗后病灶减小程度高于TP低酶活性组,周围组织的浸润程度低于TP低酶活性组,同时患者的术后生存率亦高于TP低酶活性组,差异均具有统计学意义(P＜ 0.05).结论 结直肠癌中胸苷酸磷酸化酶活性越高,XELOX化疗敏感性越高,化疗效果越好,预后相对优于TP酶活性低者.     

胸苷磷酸化酶与乳腺癌血管新生

乳腺癌具有血管新生依赖性,促血管新生因子胸苷磷酸化酶( thymidine phospho rylase, TP)在乳腺癌组织中的表达明显高于周围正常组织,可促进乳腺癌血管新生活性表型的转化。其作用机制主要与TP 特异作用于胸苷后的产物2 -脱氧- D -核糖(2-dDR)有关。2-dDR可通过诱导浓度依赖性的内皮细胞迁移,促进血管网状结构形成;诱导血氧酶1(HO -1)表达增强,通过一氧化碳(CO)的产生保护内皮细胞,增强其抗凋亡能力;诱导癌细胞的氧化应激并促进血管新生因子如VEGF、IL- 8、MMP-1的释放等多种途径促进肿瘤血管新生。缺氧及降低微环境pH可以诱导TP的表达;细胞因子或生长因子如IL- 1、TN-F α、IFN- γ可以提高TP的浓度和酶催化水平。针对TP的靶向性抗血管新生治疗是个体化性的,根据TP的表达情况可预测化疗药物疗效并选择合理的治疗,改善并提高高表达TP患者的预后。     

二氢嘧啶脱氢酶(DPD)与胸苷酸合成酶(TS)在结直肠癌中的表达及预后价值

目的:探讨5-FU代谢酶在结直肠癌中的表达及其与预后的关系.方法:44例结直肠癌根治术后分别施以5-FU为主的辅助化疗,并通过免疫组化检测二氢嘧啶脱氢酶(DPD)和胸苷酸合成酶(TS)的表达.结果:DPD阳性表达的结直肠癌无病生存期显著缩短(P=0.047),而总生存期也有缩短的趋势,但差异无显著意义(P=0.136).而TS表达与预后无关(P＞0.05),但TS在晚期肿瘤中表达较高(P＜0.05).结论:在接受5-FU为主辅助化疗的结直肠癌患者中,DPD表达可作为预后的重要指标.TS表达与临床分期密切相关,可视为结直肠癌进展的生物学标志.     

胸苷磷酸化酶与乳腺癌血管新生

乳腺癌具有血管新生依赖性，促血管新生因子胸苷磷酸化酶(thymidine phosphorylase，TP)在乳腺癌组织中的表达明显高于周围正常组织，可促进乳腺癌血管新生活性表型的转化。其作用机制主要与TP特异作用于胸苷后的产物2-脱氧-D-核糖(2-dDR)有关。2-dDR可通过诱导浓度依赖性的内皮细胞迁移，促进血管网状结构形成；诱导血氧酶-1(HDl)表达增强，通过一氧化碳(CO)的产生保护内皮细胞，增强其抗凋亡能力；诱导癌细胞的氧化应激并促进血管新生因子如VEGF、IL-8、MMP-1的释放等多种途径促进肿瘤血管新生。缺氧及降低微环境pH可以诱导TP的表达；细胞因子或生长因子如IL-1、TNF-α、IFN-γ可以提高TP的浓度和酶催化水平。针对TP的靶向性抗血管新生治疗是个体化性的，根据TP的表达情况可预测化疗药物疗效并选择合理的治疗，改善并提高高表达TP患者的预后。     

小肠、结肠、直肠

结直肠癌肝转移蛋白质组表达差异及其意义的研究//胸苷酸合成酶对结直肠癌5-Fu化疗耐药影响的前瞻性研究//采用组织芯片技术检测大肠癌组织中Ubiquitin的表达//双重器械改为“U”形套缝 吻合器超低位直肠前切除术//输尿管导管在晚期结、直肠癌术中的应用//低位直肠癌保肛手术并应用艾恒化疗的疗效//逆转录聚合酶链反应检测直肠癌淋巴结徽转移的临床意义     

Importance of thymidine phosphorylase expression in tumor stroma as a prognostic factor in patients with advanced colorectal carcinoma

Thymidine phosphorylase (TP) is a unique enzyme involved not only in angiogenesis, but in 5-fluorouracil (5-FU) metabolism as well. TP is produced by both tumor and stromal cells. The aim of this study was to reveal the clinical implication of TP localization in tumor tissues. Advanced colorectal cancer specimens (n=97) were prepared for immunohistochemical staining using monoclonal antibodies against TP, p53, vascular endothelial growth factor (VEGF), factor VIII, CD68 and thymidylate synthase (TS). Clinicopathological factors and the clinical prognosis were examined for each indicator. High tumor TP expression and high stromal TP expression were observed in 38% (36/95 cases) and 49% (47/95 cases) of the cases, respectively. High tumor TP expression tended to correlate with microvessel density (MVD) (p=0.0511). Among patients who underwent curative resection, those with high stromal TP expression had a favorable prognosis (p=0.0127). High stromal TP status was also a strong prognostic factor in the group receiving adjuvant 5-FU derivatives (p=0.0222). TP produced by tumor cells has a stimulatory effect on tumor angiogenesis, while that produced by stromal cells plays an entirely different role. The latter may enhance the anticancer effect of 5-FU via its catalyzed function.     

Blockage of 2-deoxy-D-ribose-induced angiogenesis with rapamycin counteracts a thymidine phosphorylase-based escape mechanism available for colon cancer under 5-fluorouracil therapy.

PURPOSE: Colorectal neoplasms remain a leading cause of cancer-related deaths. A recognized weakness of conventional 5-fluorouracil (5-FU) therapy relates to expression of the intracellular enzyme, thymidine phosphorylase (TP). Although TP promotes 5-FU cytotoxicity, TP-derived 2-deoxy-D-ribose (dRib) counterproductively stimulates tumor angiogenesis. Here, the newly discovered antiangiogenic drug rapamycin was combined with 5-FU to counteract the potential escape mechanism of dRib-induced angiogenesis. EXPERIMENTAL DESIGN: Orthotopic tumor growth was assessed in rapamycin and 5-FU-treated BALB/c mice with TP-expressing CT-26 colon adenocarcinoma cells. To examine liver metastasis, green-fluorescent protein-transfected CT-26 cells were visualized by fluorescence microscopy after intraportal injection. Cell counting and Ki67 staining were used to determine in vitro and in vivo cell expansion, respectively. In vitro angiogenic effects of dRib were assessed with endothelial cell migration and aortic ring assays. Western blotting detected dRib effects on p70/S6 kinase activation. RESULTS: Rapamycin treatment of mice bearing orthotopic tumors inhibited tumor growth more than did 5-FU, and mice treated with both drugs typically developed no tumors. In the liver metastasis assay, combination therapy blocked metastatic expansion of solitary tumor cells. Interestingly, complex drug activities were suggested by tumor-cell proliferation being more sensitive to 5-FU than to rapamycin in vitro, but more sensitive to rapamycin in vivo. With regard to angiogenesis, dRib-induced endothelial cell migration and aortic ring formation were completely abrogated by rapamycin, correlating with blockage of dRib-induced p70/S6 kinase activation in endothelial cells. CONCLUSIONS: Inhibition of dRib-induced angiogenesis with rapamycin counteracts a potential TP-based escape mechanism for colorectal cancer under 5-FU therapy, introducing a novel, clinically feasible, combination treatment option for this common neoplasm.     

Predictive role of thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase expression in colorectal cancer patients receiving adjuvant 5-fluorouracil

OBJECTIVE: The combined assessment of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) gene expressions in metastatic colorectal cancer has been reported to be able to predict the efficacy of fluoropyrimidine-based chemotherapy. In order to evaluate the prognostic role in the adjuvant setting, we investigated the TS, DPD and TP expression in primary tumors of colorectal cancer patients treated with 5-fluorouracil (5-FU). METHODS: TS, DPD and TP expression levels were determined by immunohistochemistry in paraffin-embedded primary tumor tissues from 62 patients with Dukes' stage B and C colorectal cancers who underwent surgery and received adjuvant systemic chemotherapy with 5-FU. The median follow-up was 90 months (range 17-127). RESULTS: Dukes' stage C cancer and high TS expression were independent markers of poor prognosis for disease-free survival (DFS; p = 0.0009 and p = 0.007, respectively) and overall survival (OS; p = 0.0005 and p = 0.011, respectively). By multivariate analysis, patients with high DPD expression had significantly shorter DFS (p = 0.007) and OS (p = 0.005) compared to patients with low DPD expression. In the combined analysis of 2 markers, patients with low TS and low DPD had the best outcome in terms of DFS (p = 0.007) and OS (p = 0.03). The analysis of all 3 proteins showed that the patients with low expression of all 3 markers had significantly longer DFS (p = 0.04) and OS (p = 0.01) than patients with a high value of any one of the protein expressions. However, the joint analysis of 3 markers (group with TS-/DPD-/TP-) could not identify a subgroup of patients with a better prognosis compared to the analysis of 2 markers (group with TS-/DPD-). The analysis of Dukes' stage C cancer patients confirmed a significant benefit in terms of DFS and OS (p = 0.001 and p = 0.006, respectively) when all 3 markers had low expression. We also found a positive significant correlation between TS and TP protein expression (p = 0.033). CONCLUSIONS: This retrospective investigation suggests that the combined assessment of TS and DPD may be useful to evaluate the prognosis of patients with Dukes' B and C colon carcinoma receiving 5-FU adjuvant chemotherapy. The role of TP as a predictor for 5-FU-based therapy needs further investigations.     

5’-脱氧氟尿苷联合干扰素对转染TP基因结肠癌细胞株裸鼠实验模型的影响

背景与目的：人结直肠癌细胞基本无胸苷磷酸化酶(thymidine phosphorylase,TP)表达。本实验主要探讨人结肠癌细胞株LS174T转染TP基因后,在裸鼠肿瘤组织中对抗癌药物5’-脱氧氟尿苷(5’-deoxy-5-fluorouridine,5’-DFUR)、氟尿嘧啶(5-fluorouracil,5-FU)和干扰素-α2a(interferon-α2a,INF-α2a)干预效果的影响。方法：以慢病毒为载体转染TP基因至结肠癌细胞株LS174T,得到稳定传代的高TP表达株。将96只BALB/c裸鼠分成2组,分别应用野生型及转染TP基因后的LS174T细胞株接种裸鼠背部皮下,制成结肠癌TP低、高表达模型。每组再随机分为6组,分别应用0.9%NaCl溶液、INF-α2a、5-FU、5-FU+INF-α2a、5’-DFUR和5’-DFUR+INF-α2a干预5 d,2周后处死裸鼠,分离肿瘤称重后,分别应用鼠抗人CD34、血管内皮生长因子(vascular endothelial growth factor,VEGF)和抗PD-ECGF单克隆抗体进行免疫组织化学染色。判定是否有TP表达及对微血管进行计数。结果：在野生型LS174T裸鼠荷瘤模型中,使用抗肿瘤药物的3~6组肿瘤质量与对照组相比均明显降低,抑癌率分别为48%、27%、48%和57%,差异有统计学意义(P<0.05)。其中5’-DFUR组(48%)与5’-DFUR+INF-α2a组(57%)、5-FU+INF-α2a组与5’-DFUR+INF-α2a组(27%与57%)相比,抑癌率差异有统计学意义(P<0.05)。在LS174T-TP细胞株裸鼠模型中,5’-DFUR组和5’-DFUR+INF-α2a组抑癌率分别为27%和48%,而使用5-FU的两组未显示出良好的抗肿瘤效果(7%和3%)。免疫组织化学染色显示,野生型LS174T接种形成的肿瘤组织中TP表达阴性,微血管数目较少,而转染TP基因后,肿瘤组织中TP表达明显上升,微血管密度明显增多(P<0.05)。结论：结肠癌细胞株LS174T转染TP基因后,在裸鼠实验肿瘤模型中,TP表达明显增加,使细胞内激活抗癌药物5’-DFUR的抗癌作用明显增强,联合应用INF-α2a能进一步增强这种抗癌作用。而转染TP基因或联合应用INF-α2a对常规抗癌药物5-FU的抗癌效果无明显影响。     

Prognostic and predictive value of thymidine phosphorylase activity in early-stage breast cancer patients

The antitumor effects of 5-fluorouracil (5-FU) and its derivatives depend upon the activity of nucleoside metabolic enzymes in tumor tissues. Thymidine phosphorylase (TP) converts 5'-deoxy-5-fluorouridine (5'-DFUR), an intermediate metabolite of capecitabine, to 5-FU. The relationship between TP expression in tumor tissues and patient survival was retrospectively examined in early-stage breast cancer patients treated with either oral 5'-DFUR administered for 6 months or surgery alone in a prospective randomized controlled trial. Thymidine phosphorylase expression in tumor cells and tumor-associated stromal (TAS) cells was examined by immunohistochemistry in 650 tissue samples from patients in this trial (n = 1217). Eight-year follow-up data showed that high TP expression in tumor cells was a significant prognostic indicator of a favorable outcome only for the patients in the 5'-DFUR group. Thus, TP expression was shown to be a predictive factor of 5'-DFUR efficacy. Conversely, a low TP expression in TAS cells was also a potent favorable prognostic indicator. These results on TP status in 2 tumor cell types could provide novel information for predicting prognosis for a patient subgroup, which would receive a probable therapeutic effect from 5'-DFUR, and presumably, from adjuvant therapy of capecitabine in early-stage breast cancer. Determination of TP status might also identify a patient subgroup whose prognosis is quite favorable even without adjuvant therapy. Further investigations on prognostic and predictive implications of TP activity in a clinical setting are warranted.     

Preferential activation of capecitabine in tumor following oral administration to colorectal cancer patients

Purpose: Capecitabine (Xeloda) is a novel fluoropyrimidine carbamate rationally designed to generate 5-fluorouracil (5-FU) preferentially in tumors. The purpose of this study was to demonstrate the preferential activation of capecitabine, after oral administration, in tumor in colorectal cancer patients, by the comparison of 5-FU concentrations in tumor tissues, healthy tissues and plasma. Methods: Nineteen patients requiring surgical resection of primary tumor and/or liver metastases received 1,255 mg/m² of capecitabine twice daily p.o. for 5–7 days prior to surgery. On the day of surgery, samples of tumor tissue, adjacent healthy tissue and blood samples were collected simultaneously from each patient, 2 to 12 h after the last dose of capecitabine had been administered. Concentrations of 5-FU in various tissues and plasma were determined by HPLC. The activities of the enzymes (CD, TP and DPD) involved in the formation and catabolism of 5-FU were measured in tissue homogenates, by catabolic assays. Results: The ratio of 5-FU concentrations in tumor to adjacent healthy tissue (T/H) was used as the primary marker for the preferential activation of capecitabine in tumor. In primary colorectal tumors, the concentration of 5-FU was on average 3.2 times higher than in adjacent healthy tissue (P=0.002). The mean liver metastasis/healthy tissue 5-FU concentration ratio was 1.4 (P=0.49, not statistically different). The mean tissue/plasma 5-FU concentration ratios exceeded 20 for colorectal tumor and ranged from 8 to 10 for other tissues. Conclusions: The results demonstrated the preferential activation of capecitabine to 5-FU in colorectal tumor, after oral administration to patients. This is explained to a great extent by the activity of TP in colorectal tumor tissue, (the enzyme responsible for the conversion of 5′-DFUR to 5-FU), which is approximately four times that in adjacent healthy tissue. In the liver, TP activity is approximately equal in metastatic and healthy tissue, which explains the lack of preferential activation of capecitabine in these tissues. Received: 4 June 1999 / Accepted: 28 October 1999     

Drug Insight: Metastatic colorectal cancer--oral fluoropyrimidines and new perspectives in the adjuvant setting

Capecitabine and uracil/ftorafur (UFT) are prodrugs of 5-fluorouracil (5-FU) that can be administered orally. Both drugs have been shown to be as effective as bolus 5-FU and folinic acid (FA), both as adjuvant treatment, and for the treatment of metastatic colorectal cancer. However, as the addition of oxaliplatin to 5-FU has been shown to improve disease-free survival in adjuvant therapy, oxaliplatin/5-FU is currently regarded as the standard adjuvant treatment, rather than fluoropyrimidine monotherapy. For the treatment of metastatic colorectal cancer, improved response rates and prolonged survival have been reported when irinotecan or oxaliplatin was added to 5-FU/FA; a further increase in efficacy was shown when bevacizumab, an antibody to vascular endothelial growth factor, was added to chemotherapy. Studies investigating the substitution of infusional 5-FU with oral compounds in combination therapy (e.g. FOLFOX versus capecitabine/oxaliplatin) are ongoing, but preliminary results in metastatic patients advise caution because of increased toxicity when used with irinotecan, and statistically non-significant trends of a decreased efficacy when used with oxaliplatin. Therefore, the combined use of oral 5-FU prodrugs plus irinotecan or oxaliplatin is not recommended at present. Oral 5-FU prodrugs, however, offer a convenient and less toxic treatment option in adjuvant treatment and in the treatment of advanced colorectal carcinoma in patients who do not want an intensified regimen, those that have contraindications for implanted venous access devices, and those who are not candidates for a combination therapy with irinotecan and oxaliplatin.