Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024623 (gastric cancer)
 36,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new class of 5-halogenated pyrimidine analogs substituted at the 6-position was evaluated as competitive inhibitors of thymidine phosphorylase (TPase). The most potent member of the series was 5-chloro-6-(2-iminopyrrolidin-1-yl)methyl-2,4(1H,3H)-pyrimidine dio ne hydrochloride (TPI), which has an apparent K(i) value of 1.7 x 10(-8) M. TPI selectively inhibited the activity of TPase, but not that of uridine phosphorylase, thymidine kinase, orotate phosphoribosyltransferase, or dihydropyrimidine dehydrogenase. In vitro inhibition studies of TPI using a thymidine analogue, 5-trifluoromethyl-2'-deoxyuridine (F(3)dThd), as the substrate demonstrated that F(3)dThd phosphorolytic activity was inhibited markedly by TPI (1 x 10(-6) M) in extracts from the liver, small intestine, and tumors of humans, from the liver and small intestine of cynomolgus monkeys, and from the liver of rodents, but not from the liver or small intestine of dogs or the small intestine of rodents, suggesting that the distribution of TPase differs between humans and animal species, and that TPI could contribute to the modulation of TPase in humans. When F(3)dThd or 5-iodo-2'-deoxyuridine (IdUrd) was coadministered to mice with TPI at a molar ratio of 1:1, the blood levels of F(3)dThd (or IdUrd) were about 2-fold higher than when F(3)dThd (or IdUrd) was administered alone. In monkeys, the maximum concentration (C(max)) and the area under the concentration-time curve (AUC) after oral F(3)dThd alone were 0.23 microg/mL and 0.28 microg. hr/mL, respectively, but markedly increased to 15.18 microg/mL (approximately 70-fold) and 28.47 microg. hr/mL (approximately 100-fold), respectively, when combined with equimolar TPI. Combined oral administration of TPI significantly potentiated the antitumor activity of F(3)dThd on AZ-521 human stomach cancer xenografts in nude mice. In conclusion, TPI may contribute not only to inhibition of TPase-mediated biological functions but also to potentiation of the biological activity of various 2'-deoxyuridine and thymidine derivatives by combining with them.
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PMID:Structure and activity of specific inhibitors of thymidine phosphorylase to potentiate the function of antitumor 2'-deoxyribonucleosides. 1073 23

Two 5-fluorouracil (5-FU)-resistant cell lines from a Korean gastric cancer cell line were established by incubation of the cells with increasing concentration of 5-FU, and the resultant cell lines showed an over 800-fold increased resistance to 5-FU. To identify the mechanism of 5-FU resistance, the expressions of genes involved in 5-FU metabolism were examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Expressions of orotate phosphoribosyltransferase (OPRT), thymidine phosphorylase (TP), and uridine phosphorylase (UP) were significantly downregulated in these cell lines, resulting in low incorporation of 5-FU into nucleic acids. In contrast, an increased expression of thymidine kinase (TK) was observed in 5-FU-resistant cells. These results strongly indicate that blocking of 5-FU incorporation into nucleic acids and TK overexpression may play a major role in 5-FU resistance in these cells. Interestingly, these cell lines showed cross-resistance to paclitaxel, cisplatin, and doxorubicin, suggesting that other factors such as HSP27 and Mn-SOD could be also involved in the mechanism of multidrug resistance in these cell lines.
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PMID:Establishment and characterization of 5-fluorouracil-resistant gastric cancer cells. 1097 11

Two patients with liver metastasis from gastric cancer who responded remarkably to a combined therapy of 5'-DFUR and PSK are reported. The first patient had liver metastases 8 months postoperatively. Her AFP level was 513 ng/ml and CEA was 30 ng/ml. After the combined therapy, all liver metastases showed a calcified change. Tumor markers of AFP and CEA decreased remarkably to the normal level within 3 weeks after the therapy. The patient had no relapse as of December 1999. The second patient with liver metastases was treated using the same combined therapy for 14 days preoperatively. The size of liver metastases had decreased remarkably by the time of the operation. A small metastasis of S8 (0.5 x 0.5 cm) was resected. No other liver metastasis was detected by intraoperative ultrasonography. The patient had no relapse as of February 2000. It is reported that PSK produces several cytokines which induce thymidine phosphorylase expression. The present report suggests that the upregulation of PyNPase might enhance the antitumor effect of 5'-DFUR.
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PMID:[Two patients with liver metastasis from gastric cancer who responded remarkably to combined therapy of 5'-DFUR and PSK]. 1105 26

The assessment of the angiogenic profile of tumors may become an important tool as a guide for the inclusion of novel drugs and molecular therapies into the standard chemoradiotherapy policy. Several studies have shown the prognostic importance of microvessel density (MVD) and of angiogenic factor expression in operable gastric cancer. In the present study we investigated, with immunohistochemistry the MVD, the expression of vascular endothelial growth factor (VEGF) and of thymidine phosphorylase (TP) expression, as well as the nuclear expression of p53 protein, in a series of patients with locally advanced inoperable gastric cancer. A strong association of VEGF with TP expression was noted (P = 0.005), and tumors coexpressing these factors had a statistically higher MVD (P = 0.0001). Nuclear p53 accumulation was also related to a high MVD (P = 0.004), and this was independent of VEGF or TP expression. Microvessel density showed a bell-shaped association with prognosis; cases with an intermediate MVD exhibit a favorable outcome (P < 0.05). A trend of nuclear TP expression to define a group of patients with poorer prognosis was noted (P = 0.06), while none of the remaining variables showed any significant association. The immunostaining results allowed the grouping of the angiogenic profile in four major categories: 1) highly vascularized tumors with VEGF and/or TP expression (about 36% of cases); 2) highly angiogenic tumors with p53 nuclear accumulation and low VEGF/TP expression (7% of cases); 3) poorly vascularized tumor with low VEGF/TP and negative nuclear p53 staining (32% of cases); 4) poorly vascularized tumors with TP expression (7% of cases). Specific therapies targeting hypoxia, VEGF, or TP expression as well as p53 gene therapy have entered clinical experimentation or are already available for clinical use. Using the suggested markers more than 80% of locally advanced gastric carcinomas can be grouped in different categories according to their angiogenic profile. Such a categorization may be useful for phase III trials on novel therapies targeting the major angiogenesis-related features studied here.
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PMID:Angiogenic interactions of vascular endothelial growth factor, of thymidine phosphorylase, and of p53 protein expression in locally advanced gastric cancer. 1106 44

The aim of this study was to investigate whether angiogenic factors influence the occurrence of spontaneous apoptosis in advanced gastric cancer. The apoptotic indices (AIs) of 97 tumors from 97 patients with advanced gastric cancer (pT3, pN0, pM0, Stage II) were analyzed by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end labeling (TUNEL) method. Intratumoral microvessel densities (IMVDs) of tumors stained with anti-CD34 monoclonal antibody were quantified under x 200 magnification using computer-assisted image analysis. The expressions of angiogenic factors, such as vascular endothelial growth factor (VEGF), thymidine phosphorylase (dThdPase), transforming growth factor-alpha (TGF-alpha), and p53 were analyzed immunohistochemically and compared with IMVDs and AIs. The mean IMVD of the 97 tumors was 365/mm2 (range 147-990/mm2). The mean AI of tumors was 2.1% (range 0-11.3%). A significant inverse correlation between the AIs and the IMVDs was shown (p = -0.278, P = 0.0064). The mean IMVDs of tumors with high expressions of dThdPase, TGF-alpha, or p53 were significantly higher than those of tumors with low expressions of these factors. The mean AI of tumors with high expressions of dThdPase was significantly lower than that of tumors with low expressions of dThdPase (P = 0.023). However, no significant correlations were detected between AIs and the expression levels of VEGF, TGF-alpha, or p53. In gastric cancer, dThdPase may play an important role in tumor progression by increasing microvessels and by suppressing apoptosis of cancer cells.
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PMID:Correlation between spontaneous apoptosis and the expression of angiogenic factors in advanced gastric adenocarcinoma. 1148 84

BACKGROUND: The immunohistochemical expression of thymidylate synthase (TS) and thymidine phosphorylase (TP) was examined in a comparative study of the recurrence rates and prognoses of patients with advanced gastric cancer at the same stage.METHODS: We examined the resected specimens of 67 patients with stage IIIB gastric cancer (pT3, pN2, M0) under 70 years of age who had undergone curative gastrectomy followed by adjuvant chemotherapy with 5-fluoropyrimidines. Paraffin sections of the resected specimens were stained with human anti-TS polyclonal and anti-TP monoclonal antibodies by the avidin-biotin-peroxidase complex (ABC) method.RESULTS: The overall expression of TS and TP was 45.4% and 43.4%, respectively. The postoperative survival curve for the TS-positive group was significantly depressed compared with that for the TS-negative group ( P = 0.0480). The survival curves for TP-positive and TP-negative groups did not show any difference. In regard to the combination of TS and TP expression, the best survival curve was obtained for the TS(-)/TP(+) group, followed by those for the TS(-)/TP(-), TS(+)/TP(-), and TS(+)/TP(+) groups in descending order. With regard to the recurrence site, there was no significant difference in peritoneal recurrence in relation to positivity for TS or TP. Lymph node recurrence, however, was significantly higher in the TS-positive and TP-positive groups, with P-values being 0.0466 and 0.0058, respectively, versus the corresponding negative groups. The incidence of hepatic recurrence was higher in the TP-positive group than in the TP-negative group ( P = 0.0910). As for the total doses of 5-fluoropyrimidines given, more favorable survival curves were obtained for the high dose of negative TS and TP groups, but no significant differences were observed in their positivities.CONCLUSION: The expressions of TS and TP showed different characteristics in overall survival and recurrence rate or site. They should be used for predicting prognosis in comprehension on their properties.
Gastric Cancer 1999 Nov
PMID:Expression of thymidylate synthase and thymidine phosphorylase in recurrence and survival rates of advanced gastric cancer. 1195 91

This study was designed to investigate the role of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) on tumour progression and sensitivity to 5'-deoxy-5-fluorouridine (5'-DFUR). Tumour tissue was obtained from surgically resected samples from 93 patients with primary gastric cancer. Tumour TP and DPD expression levels were determined by the enzyme-linked immunosorbent assay (ELISA) system and compared with several clinicopathological factors and in vitro sensitivity to 5'-DFUR. DPD showed no correlation with any clinicopathological factors. However, the TP level was significantly correlated with the depth of tumour, lymphatic invasion and venous invasion. In comparison with 5'-DFUR sensitivity, there was a weak inverse correlation between the DPD level and the sensitivity to 5'-DFUR (r(s)=-0.361). Furthermore, the TP/DPD ratio showed a significant correlation with 5'-DFUR sensitivity (r(s)=0.634). In a subgroup of patients with postoperative 5'-DFUR administration, the survival rate was significantly better in patients with a high TP/DPD ratio (n=8) than in those with low TP/DPD ratio (n=14) (P=0.0140). These results suggest that sensitivity to 5'-DFUR is predictable by measurement of both TP and DPD levels.
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PMID:Role of thymidine phosphorylase and dihydropyrimidine dehydrogenase in tumour progression and sensitivity to doxifluridine in gastric cancer patients. 1246 Jul 81

Human thymidine phosphorylase (dThdPase) is an angiogenic factor identical to platelet-derived endothelial cell growth factor (PD-ECGF). Thymidine phosphorylase is also a converting enzyme of the prodrug 5'-deoxy-5-fluorouridine (5'-DFUR) to 5-fluorouracil (5-FU) in tumors. To assess the role of dThdPase in targeting chemotherapy, we examined the relationship between the expression of dThdPase and the sensitivity of 5'-DFUR in cancer cell lines, and also examined whether transfection of dThdPase cDNA enhanced the drug-sensitivity to 5'-DFUR with or without angiogenesis in breast cancer cells. Thirteen human cancer cell lines consisting of 4 breast cancer, 6 gastric cancer, and 3 colon cancer cell lines were used. Expression of dThdPase was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). In vitro drug-sensitivity was assessed by MTT assay, and anti-tumor effect in vivo was assessed using nude mouse xenografts. Intratumoral microvessel density was evaluated by immunohistochemical staining to factor VIII related antigen. Transfection of dThdPase cDNA was performed using pcDNA3 expression vector encoding its cDNA by the lipofection method. An inverse relationship between the expression of dThdPase and the IC50 values of 5'-DFUR was observed (p=0.1278, rho=-0.440) in the 13 cancer cell lines. Transfection of dThdPase cDNA into MCF-7 breast cancer cells resulted in an approximately 2.6- and 10-fold increase of the expression of dThdPase mRNA and its enzyme activity, respectively, compared to the control vector alone. The sensitivity to 5'-DFUR in the transfected cells was increased approximately 20-fold compared to the parent cells and control vector alone, and the sensitivity to 5-FU was also somewhat increased. In contrast, the sensitivity to ADM, CDDP, and VP-16 was not different between the transfected and control cells. In nude mice xenografts of the transfected cells, treatment with 5'-DFUR had a significant anti-tumor effect compared to those of the untreated transfected cells and control vector alone treated with 5'-DFUR (p<0.01). Intratumoral microvessel density in the transfected cells was not significantly increased with or without treatment with 5'-DFUR compared to control vector alone. The high expression of dThdPase was correlated with an increase in the sensitivity to 5'-DFUR in gastrointestinal and breast cancer cell lines. The introduction of dThdPase cDNA in breast cancer cells enhanced the sensitivity to 5'-DFUR without an increase of tumor angiogenesis, and targeting chemotherapy of dThdPase may be a good tumor-specific and personalized therapy for improving the poor prognosis of cancer patients who show high expressions of dThdPase.
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PMID:Effects of introduction of dThdPase cDNA on sensitivity to 5'-deoxy-5-fluorouridine and tumor angiogenesis. 1263 76

Doxifluridine (5'-DFUR) is an anticancer drug converted to 5-fluorouracil (5-FU) by thymidine phosphorylase (TP). TP is an angiogenetic and platelet-derived endothelial cell growth factor. We evaluated the relation between TP expression and chemotherapeutic efficacy and prognosis for gastric cancer. Advanced gastric cancer patients given oral adjuvant chemotherapeutics either 5'-DFUR; 163 patients or 5-FU; 162 patients were examined. TP expression was assessed with immunohistochemical staining. Multivariate analysis for influencing survival was done, employing variables such as gender, age, procedure, tumor size, location, Borrmann type, histologic factors [type, depth of invasion, lymph node metastasis (n), lymphatic invasion (ly), and venous invasion (v)], drug administered, and TP expression. In the patients with serosal invasion, 5'-DFUR in TP positive was an independent prognostic factor (risk ratio, 4.450; 95% confidence limit, 2.099-9.436), indicating significantly improved prognosis over the 5-FU group. In TP negative, n and ly were independent prognostic factors, but the survival curves of the two chemotherapeutic groups were not significantly different. TP expression was not prognostic factor in 5'-DFUR group, while, in 5-FU group, TP expression was an independent prognostic factor (2.834, 1.467-5.476). In conclusion, it was suggested that TP positive gastric cancer with serosal invasion increased malignant potential of the tumor and 5'-DFUR efficacy.
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PMID:Thymidine phosphorylase expression correlates with malignant potential and anti-tumor effect of doxifluridine on gastric cancer: multivariate analysis for adjuvant chemotherapy doxifluridine vs. 5-fluorouracil. 1288 65

Capecitabine and docetaxel have considerable single-agent activity in gastric cancer with distinct mechanisms of action and no overlap of key toxicities. A synergistic interaction between these two drugs is mediated by taxane-induced upregulation of thymidine phosphorylase. We investigated the activity and the feasibility of capecitabine and docetaxel combination chemotherapy in patients with previously untreated advanced gastric cancer (AGC). From September 2001 to March 2003, 42 patients with AGC received 21-day cycles of oral capecitabine (1250 mg x m(-2) twice daily on days 1-14) and docetaxel (75 mg x m(-2) i.v. on day 1). The patients received a total of 164 cycles of chemotherapy. The median age was 53.5 years (range 33-73 years). The overall response rate in the 38 efficacy-evaluable patients was 60% (95% confidence interval, 45-74%). The median progression-free survival was 5.2 months (range, 1.0-15.5+ months) and the median overall survival was 10.5 months (range, 2.9-23.7+ months). The most common grade 3/4 adverse events were hand-foot syndrome (HFS: G3 50%), neutropenia (15%) and leucopenia (12%). Further studies of this combination are clearly warranted, albeit with lower doses of both agents (1000 mg x m(-2) twice daily and 60 mg x m(-2)) to reduce the rate of HFS and onycholysis.
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PMID:A phase II study of capecitabine and docetaxel combination chemotherapy in patients with advanced gastric cancer. 1505 50


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