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)

We used real-time reverse-transcription polymerase chain reaction (RT-PCR) to assay expression of the mRNA of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) in gastric cancer tissue with the objective of establishing a system to measure TS and DPD in ultra-low-volume samples. Nude mouse xenografts of 5 human gastric cancer cell lines and 85 clinical samples were used as the specimens in this study. Sensitivity to 5-fluorouracil (5-FU) was determined on the basis of the relative tumor proliferation rate in mice and the results of ATP assay using serum-free cultures of the clinical samples. mRNA expression was measured in tumor tissue by real-time RT-PCR using the ABI PRISM 7700 system. The values for expression of the mRNA for TS and DPD were corrected according to the level of glyceraldehyde-3-phosphate dehydrogenase mRNA expression. The xenografts yielded correlations between TS and DPD mRNA expression and the activity of the enzymes (TS: rs=0.700, DPD: rs=0.900), and an inverse correlation was noted between the mRNA levels and sensitivity to 5-FU (TS: rs=-0.900, DPD: rs=-0.800). The clinical samples showed an inverse correlation between 5-FU sensitivity and mRNA expression (TS: rs=-0.518, DPD: rs=-0.564). Sensitivity to 5-FU was noted only in cases in which TS mRNA expression and DPD mRNA expression were both low. Real-time RT-PCR can provide a highly sensitive assessment of TS and DPD mRNA expression in gastric cancer, and it was useful for predicting 5-FU sensitivity.
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PMID:Quantitative measurement of thymidylate synthase and dihydropyrimidine dehydrogenase mRNA level in gastric cancer by real-time RT-PCR. 1249 74

We identified two novel deletion variants of the thymidylate synthase transcript in gastric cell lines. Sequence analyses indicate that none of these variants results in introduction of a premature stop-codon or a frame shifts. In 39 gastric cancer samples, both the full-length and one-deletion variant messages were detected in cancerous as well as non-cancerous tissues. However, another isoform was found in only seven of 39 cancerous tissues. Our results provide important information to assist more detailed studies on the regulation of thymidylate synthase activity.
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PMID:Differential alternative splicing expressions of thymidylate synthase isoforms. 1270 68

To elucidate the mechanism of the enhanced antitumour activity of S-1 (1 M tegafur, 0.4 M 5-chloro-2, 4-dihydroxypyridine, and 1 M potassium oxonate) in terms of the phosphorylation and degradation pathways of 5-fluorouracil (5-FU) metabolism, we investigated tumoral thymidylate synthase (TS) content, dihydropyrimidine dehydrogenase (DPD) activity, the TS inhibition rate (TS-IR), and 5-FU incorporated into RNA (F-RNA) in four human gastric cancer xenografts (MKN-28, MKN-74, GCIY and GT3TKB) and compared the results obtained with S-1 with those obtained with 5-FU and UFT (1 M tegafur, 4 M uracil). 5-FU was administered intraperitoneally (i.p.) to mice at a dose of 50 mg/kg, three times, on days 0, 4 and 8. S-1 and UFT were administered orally at doses of 10 and 24 mg/kg, respectively, once a day, for 9 consecutive days. Antitumour activity was evaluated as the maximum inhibition of tumour growth in each animal. S-1 showed a better antitumour activity than 5-FU and UFT in tumours with a high DPD activity (GCIY and GT3TKB). There were inverse correlations between the antitumour activity and both TS content and DPD activity in the 5-FU and UFT groups. However, no such correlations were observed in the S-1 group. In GCIY and GT3TKB xenografts, TS-IR was significantly higher in the S-1 group than in the 5-FU or UFT groups. In GT3TKB xenografts, the F-RNA level was significantly higher in the S-1 group than in the 5-FU or UFT groups. The superior cytotoxicity of S-1 appears to be attributable to both an increased inhibition of DNA synthesis and an enhanced blockade of RNA function against tumours with a high DPD activity.
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PMID:Superior antitumour activity of S-1 in tumours with a high dihydropyrimidine dehydrogenase activity. 1455 32

The predictive values of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) gene expressions were retrospectively evaluated in patients with gastric cancer treated by a regimen containing S-1. The study population consisted of 53 patients registered into different two phase II studies for metastatic gastric cancer; 27 patients treated by S-1-alone study: 26 patients treated with S-1 combined with irinotecan (CPT-11). TS and DPD gene expressions in primary tumours were measured by the real-time reverse transcription PCR method. There was no statistical difference in DPD gene expression in terms of response in cases treated with S-1 alone and those treated with S-1 plus CPT-11. TS mRNA of responding tumours was lower than that of nonresponding ones when treated with S-1 (P<0.005). In the S-1-alone group, taking TS cutoff as the median values, the response rate in the low TS group was 50%, but only 8% in the high TS group (P<0.05). Patients with low TS gene expression survived longer than those with high TS gene expression (P<0.0001). However, there was no statistically significant difference in response rate and survival between patients with low TS tumours and those with high TS tumours, when the cutoff was taken as the median value of TS gene expression in the group treated with S-1 plus CPT-11. In conclusion, treatment effects of S-1 monotherapy for gastric cancer were determined by the status of TS gene expression, regardless of DPD gene expression. TS predictive power was overcome by CPT-11 combination therapy with S-1.
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PMID:Thymidylate synthase predictive power is overcome by irinotecan combination therapy with S-1 for gastric cancer. 1535 15

We investigated in a case-control study a possible role of thymidylate synthase gene (TS) polymorphisms for gastric cancer susceptibility. Lymphocyte genomic DNA from 134 Italian gastric cancer patients and 139 controls was used for genotyping two polymorphisms in the TS 5'-untranslated region (5'-UTR); a double (2R) or triple (3R) 28-bp repeat and a G/C polymorphism within the triple repeats allele (3G allele). Samples were also genotyped at a 6-bp deletion/insertion (del6 or ins6) polymorphism at position 1494 in the TS 3'-untranslated region (3'-UTR). Unconditional regression with odd ratios (OR) and 95% confidence intervals (CI), haplotype and linkage disequilibrium analyses were used to investigate the association of the polymorphisms with the disease. The global allelic distribution was in Hardy-Weinberg equilibrium. Genotypes with the 3G allele (2R/3G, 3C/3G, 3G/3G) were significantly more frequent in patients than controls and were associated with gastric cancer risk (OR = 2.06; 95% CI = 1.26-3.35). A significant risk was also observed for carriers of the del6 allele in the 3'-UTR. Odds ratios for combined 3G-del6/ins6 and 3G-del6/del6 genotypes were 2.59 (95% CI = 1.36-4.94) and 2.81 (95% CI = 1.22-6.64), respectively. The 3G-del6 haplotype showed a significant association with the disease (p = 0.01). Polymorphisms in the TS gene may contribute to gastric cancer susceptibility and this finding deserve further investigation in the context of novel strategies for gastric cancer prevention. In vitro, 3G genotypes have been related to high TS mRNA expression, which may underlie one of the possible etiologic mechanisms.
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PMID:Association of thymidylate synthase polymorphisms with gastric cancer susceptibility. 1538 66

Fruits and certain vegetables have a protective effect on gastric cancer (GC) and folate is one of the nutrients in fruits and vegetables. We hypothesized that the polymorphisms of thymidylate synthase (TYMS) gene involved in folate metabolism are associated with GC risk. In a population-based case-control study of 337 GC cases and 326 controls, frequency-matched by age, sex and residential areas in a southern Chinese population, we genotyped the 28 bp tandem repeat in the TYMS 5'-untranslated enhanced region (TSER) and the 6 bp deletion/insertion at bp 1494 in the TYMS 3'-untranslated region (TS3'UTR). We found that although the TSER polymorphism had no main effect on GC risk, the TS3'UTR 6 bp/6 bp genotype was associated with a significantly increased risk of GC [adjusted odds ratio (OR) = 1.96, 95% confidence interval (CI) = 1.18-3.25], especially the non-cardiac gastric cancer (2.16, 1.22-3.82), compared with the 0 bp/0 bp genotype. However, when we evaluated these two polymorphisms together and used the combined genotype with zero variant allele (TSER 2R and TS3'UTR 6 bp variant alleles) as the reference, we found that the combined genotype with three or four variant alleles was associated with a significantly increased risk of GC (2.06, 1.12-3.79), especially the non-cardiac gastric cancer (2.33, 1.19-4.59), and this significant association was more pronounced among older women (>60 years old), non-smokers, and never tea drinkers. In conclusion, the TYMS polymorphisms, especially the TS3'UTR polymorphism, are associated with GC risk, especially the non-cardiac gastric cancer, and the TSER 2R and TS3'UTR 6 bp alleles may jointly play a role in the etiology of GC in the southern Chinese population. Larger studies are warranted to verify these findings.
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PMID:Polymorphisms of thymidylate synthase in the 5'- and 3'-untranslated regions associated with risk of gastric cancer in South China: a case-control analysis. 1593 32

Pemetrexed is a newly developed multitargeted antifolate with promising clinical activity in many solid tumors including gastric cancer. The aim of the present study was to evaluate the cytotoxicity of pemetrexed and its mode of interaction with cisplatin in gastric cancer cell lines, and to identify genes associated with sensitivity to pemetrexed. The cytotoxic activity of pemetrexed was assessed by tetrazolium-based colorimetric assay (MTT assay) and the interaction between pemetrexed and cisplatin was evaluated by the isobologram method. Western immunoblotting and real time RT-PCR analysis of thymidylate synthase (TS), folylpoly-gamma-glutamate synthetase (FPGS) and reduced folate carrier (RFC1) were performed in order to determine whether sensitivity to pemetrexed would be predictable by protein or mRNA expression levels. Pemetrexed was more cytotoxic than 5-fluorouracil, with IC50 between 17 and 310 nM in most of the gastric cancer cell lines examined and the pemetrexed/cisplatin combination resulted in additive or synergistic interaction. The protein expressions of TS, FPGS, and RFC1 were significantly associated with IC50 for 5-fluorouracil, but no such association was found for pemetrexed chemosensitivity. The mRNA expressions of RFC1, FPGS and other target and resistance related genes revealed no significant association with pemetrexed sensitivity. In conclusion, pemetrexed is active against gastric cancer cell lines and the pemetrexed/cisplatin combination showed a synergistic or additive interaction, supporting its clinical use in gastric cancer. Drug sensitivity toward pemetrexed could not be predicted by the expressions of TS, RFC1, or FPGS and we suggest that it is determined by interactions between multiple genes.
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PMID:Cytotoxic effects of pemetrexed in gastric cancer cells. 1595 60

Metabolizing enzymes such as thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) have long been known to be useful for predicting response and outcome in patients receiving 5-fluorouracil (5-FU). However, few studies have examined the cancerous tissue levels of 5-fluorodeoxyuridine 5'-monophosphate (FdUMP), a metabolite of 5-FU that has an important role in inhibiting DNA synthesis. In this study, for the first time to our knowledge, we measured concentrations of FdUMP in tumor specimens and surrounding non-cancerous tissue obtained at operation in 10 patients with gastric cancer who received TS-1 before surgery (80 mg/m2, 3 days). The FdUMP level in the cancerous tissue was significantly higher than that in the non-cancerous tissue (153.0 +/- 85.7 pmol/g tissue vs. 53.0 +/- 47.0 pmol/g tissue)(p = 0.0046). Furthermore, the TS level in tumor was significantly higher than that in non-cancerous tissue (6.362 +/- 5.106 pmol/g tissue vs. 2.092 +/- 2.050 pmol/g tissue) (p = 0.0310). The mean ratios of TS-bound FdUMP to TS and FdUMP concentrations in the cancerous tissues were 45.9% and 2.00%, respectively. Our results demonstrate that in cancerous tissue, TS-1 may produce high FdUMP concentration and suppress about half FdUMP concentration by forming ternary complexes.
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PMID:Level of 5-fluorodeoxyuridine 5'-monophosphate in cancerous tissue in patients with gastric cancer under preoperative administration of TS-1. A preliminary study. 1627 May 33

To evaluate the predictive value of a panel of gene polymorphisms involved in metabolism of 5-FU and cisplatin on clinical outcome in advanced gastric cancer patients. A total of 52 patients were enrolled in this study. DNA was extracted from paraffin-embedded tumour specimen. Genotypes were determined using PCR-RFLP. Median survival time was 6.0 months (95% CI 3.9;8.1). Overall response rate was 26%. Patients possessing the glutathione S-transferase P1-105 Valine/Valine (GSTP1-105VV) genotype showed a response rate of 67% compared to 21% in patients harbouring at least one GSTP1-105 Isoleucine (GSTP1-105I) allele (P=0.038). GSTP1-105VV patients demonstrated a significant superior median survival time of 15.0 months (95% CI 7.8;22.0) compared to 6.0 months (95% CI 5.1;7.0) in patients with at least one GSTP1-105I allele (P=0.037). Patients possessing a favourable thymidylate synthase (TS) genotype (2R/2R, 2R/3RC, 3RC/3RC) experienced a superior survival time of 10.2 months (95% CI 5.1;15.3) compared to 6.0 months (95% CI 5.0;7.0) in patients with unfavourable TS genotypes (P=0.099). Patients harbouring the GSTP1-105II genotype and one of the unfavourable TS genotypes showed an inferior median survival time of 6.0 months (95% CI 3.9;8.1) compared to 11 months (95% CI 6,23;15,77) in patients with either GSTP1-105VV or a favourable TS genotype (P=0.044). Testing for TS and GSTP1 polymorphisms may allow identification of gastric cancer patients who will benefit from 5-FU/cisplatin chemotherapy, sparing others the side effects of this chemotherapy.
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PMID:Polymorphisms of glutathione S-transferases (GST) and thymidylate synthase (TS)--novel predictors for response and survival in gastric cancer patients. 1704 83

To investigate the relationship between polymorphism in the 3'-untranslated region (3'-UTR) of the thymidylate synthase (TS) gene and sensitivity of gastric cancer to 5-fluorouracil (5-FU)-based chemotherapy, 106 cases of advanced gastric cancer were analyzed. All patients were treated with 5-FU-based chemotherapy; DNA from peripheral blood leukocytes was obtained before therapy. TS 3'-UTR genotypes were detected by PCR-RFLP. Polymorphism in the TS 3'-UTR can be classified into three groups according to the presence or absence of a 6 bp nucleotide fragment: the -6/-6 bp, -6/+6 bp and +6/+6 bp groups. The response rate of the -6/-6 bp and -6/+6 bp groups was found to be significantly higher than the +6/+6 bp group. These results show that the presence of the TS 3'-UTR 6 bp nucleotide fragment can be correlated with the sensitivity of gastric cancer to 5-FU-based chemotherapy, and that the TS 3'-UTR polymorphism profile can be used to guide the choice of 5-FU-based chemotherapy in advanced gastric cancer.
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PMID:Polymorphism in the 3'-untranslated region of the thymidylate synthase gene and sensitivity of stomach cancer to fluoropyrimidine-based chemotherapy. 1642 79


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