Expression of thymidine phosphorylase and angiogenesis in human ovarian tumor

Thymidine phosphorylase (dThdPase) is an enzyme involved in pyrimidine nucleoside metabolism. dThdPase activity is increased in various types of malignant tumors. Recently, we demonstrated that dThdPase is identical to platelet-derived endothelial cell growth factor (PD-ECGF), and has angiogenic activity. We measured the dThdPase activity and the level of thrombomodulin (TM), as a marker for endothelial cells, in ovarian carcinomas, benign tumors and normal ovarian tissues. The average dThdPase activity of ovarian carcinomas (10.86+/-6.98 nmol/100 mu g protein/h) was significantly higher than that of benign tumors (4.66+/-3.91 nmol/100 mu g protein/h) or normal tissues (2.52+/-1.90 nmol/100 mu g protein/h). The expression of dThdPase detected by immunoblot analysis was well correlated with dThdPase activity. In an immunohistochemical study, the expression of dThdPase was more frequently observed in ovarian carcinomas than in benign tumors or normal tissues. dThdPase activity in human ovarian carcinomas was significantly correlated with the expression of TM in human ovarian carcinomas. These findings suggest that dThdPase expression is significantly correlated with angiogenesis in ovarian tumors.     

Thymidine phosphorylase activity and angiogenesis in gastric cancer.

Angiogenesis has an important role in the growth and metastasis of solid tumors. Several angiogenic factors have been identified, one being platelet-derived endothelial cell growth factor (PD-ECGF), which is identical to thymidine phosphorylase (dThdPase). We investigated the activity of dThdPase in 84 samples of 42 human gastric cancers, by liquid chromatography. The dThdPase activity significantly correlated to the microvessel density assessed by immunostaining to CD-31 antigen (P<0.05). Expression of dThdPase has an important role in the promotion of angiogenesis in human gastric cancer.     

Suppression of thymidine phosphorylase-mediated angiogenesis and tumor growth by 2-deoxy-L-ribose

Thymidine phosphorylase (TP), an enzyme involved in the reversible conversion of thymidine to thymine, is identical to an angiogenic factor, platelet-derived endothelial cell growth factor (PD-ECGF). Both TP and one of the TP-degradation products of thymidine 2-deoxy-D-ribose (dRib) display endothelial cell chemotactic activity in vitro and angiogenic activity in vivo. Recently, we demonstrated that 2-deoxy-L-ribose (lRib) could abolish the inhibitory effect of dRib on hypoxia-induced apoptosis. This suggested that lRib may be a useful inhibitor of dRib and thereby of TP functions. Therefore, we investigated the ability of lRib to inhibit the range of biological activities of TP and dRib. lRib suppressed both dRib-induced endothelial cell migration in a chemotaxis assay and endothelial tube formation induced by dRib in a collagen gel. lRib could also suppress the biological effects of TP in vivo assays of angiogenesis and tumor growth. Thus, in a corneal assay of angiogenesis, lRib inhibited angiogenesis induced by the implantation of recombinant TP. In a dorsal air sac assay of angiogenesis, lRib inhibited angiogenesis induced by the implantation of KB cells overexpressing TP (KB/TP). In a tumor growth assay, lRib treatment considerably decreased the growth rate of KB/TP cells xenografted into nude mice and also resulted in an increase in the proportion of apoptotic cells in KB/TP tumors. These findings demonstrate that TP and dRib play an important role in angiogenesis and tumor growth, and that these effects can be inhibited by lRib. Thus, lRib is a potentially useful agent for the suppression of TP-dependent angiogenesis and tumor growth.     

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。     

Thymidine phosphorylase is regulated by tamoxifen in T47D breast cancer cell line

BACKGROUND: Thymidine phosphorylase (TP) has diverse functions within cells, including increasing the sensitivity of cancer cells to cytotoxic drugs including 5-fluorouracil (5-FU) and methotrexate. However, the regulators of TP still remains largely unknown. METHOD: In this study, we examined whether tamoxifen has specific effects on TP expression in the T47D breast cancer cell line. We studied the TP expression in the T47D cell line before and after tamoxifen treatment using Western blot analysis and ELISA. RESULTS: We found that TP expression is significantly up-regulated in tamoxifen-treated cells compared with control. CONCLUSIONS: Our findings suggest that tamoxifen may increase chemotherapy sensitivity through TP up-regulation for treatment regimens including doxifluridine, capecitabine, and/or methotrexate.     

Suppression of metastasis by thymidine phosphorylase inhibitor

We developed a novel inhibitor of thymidine phosphorylase (TP), 5-chloro-6-[1-(2-iminopyrrolidinyl) methyl] uracil hydrochloride (TPI), that is about 1000-fold more active than 6-amino-5-chlorouracil, one of the most potent TP inhibitors. TPI inhibited the high chemotactic motility and basement membrane invasion of KB/TP cells, a TP-positive clone transfected with Rous sarcoma virus (RSV)/TP, to the levels seen in KB/CV cells, a control clone transfected with RSV. In nude mice, oral administration of TPI suppressed not only macroscopic liver metastases of highly metastatic KB/TP cells but also the level of human beta-globin as a molecular marker of micrometastases in the livers of the mice. These findings demonstrate that TP plays a key role in the invasiveness and metastasis of TP-expressing solid tumors and suggest that TPI might be a novel antimetastatic agent for blood-borne metastasis.     

The effect of a thymidine phosphorylase inhibitor on angiogenesis and apoptosis in tumors

Thymidine phosphorylase (TP) is an enzyme involved in the reversible conversion of thymidine to thymine and is identical to an angiogenic factor, platelet-derived endothelial cell growth factor. TP is expressed at higher levels in a wide variety of solid tumors than in the adjacent nonneoplastic tissues. Patients with TP-positive colon and esophageal tumors have a poorer prognosis than those with TP-negative tumors. We have recently synthesized a new TP inhibitor (TPI), 5-chloro-6-[1-(2-iminopyrrolidinyl) methyl] uracil hydrochloride. We investigated the effect of TPI on angiogenesis in KB cells transfected with platelet-derived endothelial cell growth factor cDNA, KB/TP, and a mock transfectant, KB/CV, using the mouse dorsal air sac assay model. We found that KB/TP cells had a higher angiogenic ability than KB/CV cells and that TPI completely suppressed angiogenesis by KB/TP. Furthermore, at a dose of 50 mg/kg/day, TPI considerably decreased the growth rate of KB/TP cells xenografted into nude mice. Microvessel density in KB/TP tumors was higher than that in KB/CV tumors, and TPI did not significantly change the density in either of the tumors. The apoptotic index in KB/TP tumors was significantly lower than that in KB/CV tumors, and TPI significantly increased the apoptotic index in KB/TP tumors but not in KB/CV tumors. These findings, taken together with previous reports, suggest that the expression of TP plays an important role in tumor growth and that TPI suppresses tumor growth by increasing the proportion of apoptotic cells and probably inhibiting angiogenesis.     

The expression of platelet-derived endothelial cell growth factor/thymidine phosphorylase associates with angiogenesis in epithelial ovarian cancer

Background The object of this study is to clarify the association of an angiogenic factor, PD-ECGF (platelet-derived endothelial cell growth factor/thymidine phosphorylase), with clinicopathologic factors, in this case tumor angiogenesis, in epithelial ovarian cancers. Methods Tumor specimens were obtained at the time of surgery from the primary lesion in 60 patients with epithelial ovarian cancer. Histologic cell types were assigned to tumors according to the World Health Organization classification: 26 were classified as serous adenocarcinoma, 15 as endometrioid adenocarcinoma, 9 as mucinous adenocarcinoma, 9 as clear cell carcinoma, and 1 as undifferentiated carcinoma. Surgical staging was based on the international Federation of Gynecology and Obstetrics (FIGO) staging system: 16 were stage I, 6 were stage II, 34 were stage III, and 4 were stage IV. Expression of PD-ECGF was evaluated by immunohistochemical staining. Microvessel density was assessed by immunostaining for factor VIII-related antigen in the most neovascularized area. Results Stroma cells stained more strongly than cancer cells (80% vs. 33%). The immunopositivity of PD-ECGF in stroma cells was higher in cases of advanced cancer. Expression of PD-ECGF in mucinous adenocarcinomas was significantly higher than that in serous adenocarcinomas, while PD-ECGF expression in clear cell carcinomas was significantly lower. The microvessel density in the cases with marked PD-ECGF-positive stroma cells was significantly higher than that in the cases with absent/minimal PD-ECGF-positive stroma cells (P<0.05). Conclusion The expression of PD-ECGF may play a crucial role in the promotion of angiogenesis in epithelial ovarian cancers.     

胸腺嘧啶磷酸化酶在结直肠癌组织中的表达

目的研究胸腺嘧啶磷酸化酶(thymidine phosphorylase,TP)在结直肠癌组织中的表达,为临床用药提供指导.方法运用实时荧光定量RT-PCR和ELISA方法分别从mRNA和蛋白质水平对TP在结直肠癌组织及相邻正常组织中的表达进行检测.结果无论是在mRNA还是蛋白质水平,肿瘤组织中的TP表达高于其相邻正常组织,肿瘤组织中的TP蛋白水平为7.82±4.31 ng/μgTPO,mRNA水平为1.66±0.766;正常组织中TP蛋白水平为5.03±2.48 ng/μgTPO,mRNA水平为1.05±0.60;并且ELISA结果与实时RT-PCR结果具有一定的相关性(γ=0.81).结论胸腺嘧啶磷酸化酶在结直肠肿瘤中的表达对于临床使用5-FU类药物具有指导意义.     

胸苷磷酸化酶在胃癌中的表达及临床意义

目的：探讨胸苷磷酸化酶（ＴＰ）在胃癌中的表达及临床意义。方法：采用免疫组织化学法检测２０４例胃癌患者肿瘤组织中ＴＰ的表达,并探讨与临床病理因素、术后辅助化疗和预后之间的关系。结果：胃癌组织ＴＰ表达阳性率为４７.１％。ＴＰ阳性表达患者中位生存时间为３０.９４个月,ＴＰ阴性表达患者为３４.４３个月,两者比较有显著的统计学差异（Ｐ＝０.００２）。ＴＰ阳性表达与患者年龄、发病部位、ＴＮＭ分期、浸润深度、淋巴结转移等病理因素以及与以氟尿嘧啶为主的辅助化疗的疗效无明显相关性。结论：ＴＰ表达与胃癌患者长期生存有一定的相关性,有可能成为预测胃癌预后的一个参考指标。     

Plumbagin inhibits tumorigenesis and angiogenesis of ovarian cancer cells in vivo

Angiogenesis is a hallmark of tumor development and metastatic progression, and anti‐angiogenic drugs targeting the VEGF pathway have shown to decrease the disease progression in cancer patients. In this study, we have analyzed the anti‐proliferative and anti‐angiogenic property of plumbagin in cisplatin sensitive, BRCA2 deficient, PEO‐1 and cisplatin resistant, BRCA2 proficient PEO‐4 ovarian cancer cells. Both PEO‐1 and PEO‐4 ovarian cancer cells are sensitive to plumbagin irrespective of BRCA2 status in both normoxia and hypoxia. Importantly, plumbagin treatment effectively inhibits VEGF‐A and Glut‐1 in PEO‐1 and PEO‐4 ovarian cancer cells. We have also analyzed the p53 mutant, cisplatin resistant, and BRCA2 proficient OVCAR‐5 cells. Plumbagin challenge also restricts the VEGF induced pro‐angiogenic signaling in HUVECs and subsequently endothelial cell proliferation. In addition, we observe a significant effect on tumor regression among OVCAR‐5 tumor‐bearing mice treated with plumbagin, which is associated with significant inhibition of Ki67 and vWF expressions. Plumbagin also significantly reduces CD31 expression in an ear angiogenesis assay. Collectively, our studies indicate that plumbagin, as an anti‐cancer agent disrupts growth of ovarian cancer cells through the inhibition of proliferation as well as angiogenesis.     

Significance of tissue thymidine phosphorylase and dihydropyrimidine dehydrogenase activities in ovarian cancer

Thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) are important enzymes in the pyrimidine salvage pathway. In the meantime, TP and DPD are a converting enzyme of 5'-DFUR to 5-FU and the major catabolic enzyme of 5-FU, respectively. Because little is known about their protein expressions in ovarian cancers, we investigated TP and DPD protein expressions quantitatively in 24 ovarian cancers and their normal counterparts by ELISA. Higher TP expression was observed in ovarian cancers than in normal ovaries. The higher expression was also correlated with the histological grade and clinical stage. No relation was observed between the expression of DPD and the clinical and pathological parameters. The higher TP/DPD ratio, which appears to be a predictor of 5-fluorouracil sensitivity, was observed in ovarian cancers than in normal counterparts. In univariate analysis, a higher TP/DPD ratio was found to be a predictor of progression-free survival in ovarian cancer patients. This would suggest that capecitabine and 5'-DFUR are potential candidates for ovarian cancer chemotherapy.     

骨肉瘤中胸苷磷酸化酶的表达与血管生成的关系

目的:研究胸苷磷酸化酶/血小板衍化内皮细胞生长因子(TP/PD-ECGF)在骨肉瘤组织中的表达与微血管密度(MVD)的关系及其临床病理意义.方法:应用免疫组织化学SP法,检测54例骨肉瘤组织中TP/PD-ECGF的表达,CD34单克隆抗体标记血管内皮细胞计数骨肉瘤MVD.结果:骨肉瘤TP/PD-ECGF表达程度与MVD呈正相关,骨肉瘤TP/PD-ECGF低表达组、中表达组、高表达组的MVD计数有统计学差异;骨肉瘤TP/PD-ECGF表达与骨肉瘤临床病理因素无统计学关联,但与是否肺转移显著相关.结论:TP/PD-ECGF是骨肉瘤血管形成的一种重要调节因子,在骨肉瘤肺转移中起一定作用.     

Blockade of paclitaxel-induced thymidine phosphorylase expression can accelerate apoptosis in human prostate cancer cells

Recently, survival benefit by chemotherapy using paclitaxel (PTX) and the induction of thymidine phosphorylase (TP) by PTX have been reported in several solid tumors. On the other hand, TP confers antiapoptotic effect on tumor cells through inhibition of caspase-8 activation in vitro. On the basis of these previous observations, we hypothesized that (a) TP can be induced after PTX treatment in human prostate cancer (PC) and (b) blockade of PTX-induced TP expression can enhance the apoptotic processes in human PC cells. PTX was used to find TP expression in all eight hormone-refractory PC cases after chemotherapy; however, cleaved caspase-8 was not expressed after chemotherapy in the six hormone-refractory PC cases with strong TP expression. In PC cell lines (PC-3, DU 145, and LNCaP), TP expression after PTX treatment was clearly up-regulated in a dose-dependent manner. Cell viability of PC cell lines treated with PTX and TP antisense was significantly reduced in a time-dependent and dose-dependent manner compared with the PTX treatment alone. Likewise, apoptotic index of PC cells treated with PTX and TP antisense was significantly increased in comparison with PTX alone. After complete blockade of PTX-induced TP translation by TP antisense transfection, cleaved form of caspase-3 and poly(ADP-ribose) polymerase was increased, and this exaggeration of apoptosis also ran parallel with caspase-8 activation in a PTX dose-dependent manner. However, in PC cell lines treated with TP antisense alone, neither caspase-3 nor poly(ADP-ribose) polymerase was cleaved despite caspase-8 activation. These results indicate that PTX-induced TP up-regulation is associated with decreased caspase-8 activation. This study is the first report showing that blockade of PTX-induced TP expression could exaggerate the processing of apoptosis in PC cells treated with PTX. Our results provide preclinical evidence that TP could be a new molecular target for enhancing the potency of PTX-mediated apoptosis in PC cells.     

胸苷磷酸化酶在癌组织中表达的研究

目的　研究胸苷磷酸化酶 (TP)在不同种类癌组织中的表达 ,探讨TP与癌组织血管生成的关系。方法　采用免疫组织化学方法检测 2 5 1例癌组织和相对应的 92例正常组织TP和微血管密度 (MVD)的表达。癌组织包括 :胃癌 4 8例 ,大肠癌 5 3例 ,乳腺癌 4 7例 ,宫颈癌 5 6例 ,肺癌 4 7例 ;正常组织包括 :胃 2 5例 ,大肠 2 5例 ,宫颈 17例 ,肺 2 5例。分析癌组织和正常组织TP表达差异 ,及癌组织TP表达与癌组织MVD的关系。结果　胃癌、大肠癌、乳腺癌、宫颈癌和肺癌的TP表达阳性率分别为6 4 .6 %、6 7.9%、80 .9%、82 .1%和 6 3.8%。癌组织的TP表达阳性率显著高于正常组织 (P =0 .0 0 0 0 )。癌组织TP表达与胃癌、大肠癌、乳腺癌、宫颈癌的MVD值关系密切 (P <0 .0 0 1)。结论　TP在胃癌、大肠癌、乳腺癌、宫颈癌和肺癌组织中过度表达 ,并对胃癌、大肠癌、乳腺癌和宫颈癌的血管生成有明显促进作用。