OBJECTIVETo explore the influence of 5'UTR tandem repeat and 3'UTR 6 bp deletion polymorphism of thymidylate synthase (TS) gene on the development and lymphatic metastases of esophageal squamous-cell carcinoma (ESCC).

METHODSPeripheral leucocyte DNA was extracted from 232 ESCC patients and 348 age- and sex-matched healthy controls. TS 5'UTR and 3'UTR genotyping in all study subjects was performed by PCR fragment analysis and PCR-RFLP analysis, respectively.

RESULTSThe distribution of TS 5'UTR and 3'UTR variants in ESCC patients was not significantly different from that in healthy controls. However, individuals with 6 bp+/6 bp+ and 3R/3R genotypes significantly reduced the risk to ESCC development compared to those with other genotype combinations (adjusted OR = 0.32, 95% CI = 0.08-0.92). In addition, the frequency of 2R/3R genotype in ESCC patients with lymphatic metastases (40%) was significantly higher than that in lymph node negative cases (14.7%) (chi(2) = 10.11, P = 0.001). Compared to 3R/3R genotype, the 2R/3R genotype significantly increased the risk of lymphatic metastases in ESCC (adjusted OR = 3.68, 95% CI = 1.54-8.93).

CONCLUSIONThe genotyping of TS 5'UTR and 3'UTR polymorphisms might be used as a stratification maker for predicting susceptibility to ESCC. The TS 5'UTR 2R/3R genotype might be a candidate molecular marker to predict the potential of lymphatic metastases in ESCC.

Biomarkers, Tumor ; Carcinoma, Squamous Cell ; genetics ; secondary ; Esophageal Neoplasms ; genetics ; pathology ; Genotype ; Humans ; Lymphatic Metastasis ; Polymorphism, Genetic ; Tandem Repeat Sequences ; genetics ; Thymidylate Synthase ; genetics

OBJECTIVETo investigate the influence of thymidylate synthase (TS) gene polymorphisms on high-dose methotrexate (HD-MTX)-related toxicities in childhood acute lymphoblastic leukemia (ALL).

METHODSA total of 73 children who were diagnosed with ALL between March 2011 and March 2013 were included into this study. Genomic DNAs were extracted from their peripheral blood. And then the genotypes of TS 5'-UTR were determined by direct DNA sequencing after PCR. The toxicity response of 73 patients receiving HD-MTX chemotherapy were observed and recorded, and plasma MTX concentrations at 42-48 hours after chemotherapy were measured.

RESULTSThe main HD-MTX-related toxicities of 73 patients receiving HD-MTX chemotherapy were neutropenia, decreased hemoglobin level, thrombocytopenia, liver toxicity, mucosal damage, and gastrointestinal reactions. There were no significant differences in the incidence rate of HD-MTX-related toxicities between children with different TS 5'-UTR genotypes after chemotherapy (P>0.05). TS 5'-UTR genotype was not significantly correlated with plasma MTX concentrations at 42-48 hours after chemotherapy (P>0.05).

CONCLUSIONSTS gene polymorphisms have no influence on the incidence of HD-MTX-related toxicities in childhood ALL.

Antimetabolites, Antineoplastic ; adverse effects ; Child ; Child, Preschool ; Female ; Genotype ; Humans ; Infant ; Male ; Methotrexate ; adverse effects ; Polymorphism, Genetic ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; drug therapy ; genetics ; Thymidylate Synthase ; genetics

INTRODUCTIONColorectal cancer is the most common form of malignancy in Taiwan and the third leading cause of death from cancer, preceded only by lung and hepatic cancers. Colorectal cancer is typically treated by surgical intervention and/or chemotherapy and radiotherapy, if necessary. To date, 5-fluorouracil (5-FU) is the most commonly used anti-cancer chemotherapy drug. However, patients commonly experience resistance to the drug therefore limiting its efficiency. In this study, we measured the expression of rTSbeta in human colon cancer as a novel 5-FU resistance marker.

MATERIALS AND METHODSWe collected 172 colon cancer samples from 4 different hospitals (including 21 pairs of colon cancer biopsies and 151 pathologic slides of colon cancer). In vitro, we measured the cytotoxicity of 5-FU and 5-FU plus leucovorin in H630 and H630-1 colon cancer cell lines.

RESULTSThe results revealed that rTSbeta was expressed in 115 (66.9 %) pathology samples and that tumour expression was higher than in corresponding normal tissue. Survival rates of up to 5 years following treatment was significantly higher for patients without rTSbeta expression than for those with rTSbeta expression (P = 0.0023). In vitro, H630-1 (with rTSbeta overexpression) had significantly higher IC50 of 5-FU than did H630. IC50 of 5-FU decreased when leucovorin was added.

CONCLUSIONSResults indicate a close relationship between rTSbeta expression and resistance to the drug 5-FU in human colorectal cancer. These results provide further evidence for rTSbeta expression as a novel 5-FU resistance marker of colorectal cancer.

Biomarkers ; Cell Line, Tumor ; drug effects ; Colorectal Neoplasms ; drug therapy ; Cytological Techniques ; Drug Resistance, Neoplasm ; physiology ; Fluorouracil ; pharmacology ; therapeutic use ; Humans ; In Vitro Techniques ; Taiwan ; Thymidylate Synthase ; genetics ; metabolism

OBJECTIVETo investigate the effect of the RNAi and the chemotherapy drugs nolatrxed on the expression of thymidylate synthase(TS) and the growth of the colorectal carcinoma LOVO cells.

METHODSThe siRNA was constructed targeting the human TS gene, and then transfected into the human colorectal cancer LOVO cells. RT-PCR and Western blot technique were used to observe the TS gene and protein expression levels, and MTT was used to detect cell proliferation after silencing the TS gene. In addition, siRNA and nolatrxed were applied to the LOVO cells to observe the TS protein expression and cell growth.

RESULTSTS siRNA significantly reduced the expression of TS gene and protein in LOVO cells, and inhibited cell growth. The IC50 value of LOVO cells was (1.46±0.25) μmol/L in TS siRNA combined with nolatrexed group, (6.81±0.31) μmol/L in the negative control group, and (6.47±0.43) μmol/L in the single nolatrexed group. After treatment of TS siRNA combined with nolatrexed on LOVO cells for 36 hours, the apoptosis index was higher than that in single TS siRNA and nolatrexed[(62.12±0.89)% vs.(21.56±0.67)% and(40.51±0.83)%, both P<0.05].

CONCLUSIONTS siRNA can partly suppress the expression of TS gene in LOVO cells, inhibit cell proliferation, promote cell apoptosis and enhance cell sensitivity to apoptosis induced by nolatrexd.

Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colorectal Neoplasms ; enzymology ; pathology ; Humans ; Quinazolines ; pharmacology ; RNA Interference ; Thymidylate Synthase ; genetics ; metabolism

To construct a vector for DNA vaccine and protein expression by using chromosome-plasmid balanced lethal system which was based on the thyA+ gene/deltathyA Escherichia coli. The thyA genes from Escherichia coli and Vibrio cholerae were amplified by polymerase chain reaction and cloned into pCDNA3 by replacing ampilicilin resistant gene. Multiple cloning sites, the prokaryotic replicon, CMV promoter and the boving growth hormone polyA signal were also included in the vectors. Two new non-antibiotic recombinant plasmids renamed as pcDNATE and pcDNATC which had the nutritional marker as thyA were constructed and were transformed respectively into the deltathyA derivative of E. coli K-12 strain DY330-TI, then two chromosome-plasmid balanced systems for E. coli based on the thyA were developed. To test the efficiency and stability of the newly constructed chromosome-plasmid balanced lethal system, a reporter gene--red fluorescent protein (DsRed2) gene was cloned into pcDNATE, pcDNATC and expressed as fusion to the c-myc. The two recombinant plasmids, pcDNATE-DsRed2, pcDNATC-DsRed2, were transfected into HEK293 solely and DsRed2-myc was detected by the fluorescence microscope assay and western-blot. Meanwhile, the loss of recombinant plasmids were not seen in cultures without thymidine after 20 generations. The chromosomal-plasmid balanced lethal system is proved to be an effective vector system for the expression of target genes and share the same stability with the antibiotic-resistant plasmid vector system. It holds great potential in gene vaccine vector because obviating the weakpoints of the drug resistance marker during application.
Bacterial Proteins ; genetics ; metabolism ; Blotting, Western ; Cell Line ; Chromosomes, Bacterial ; genetics ; Escherichia coli ; enzymology ; genetics ; metabolism ; Genetic Vectors ; genetics ; Humans ; Microscopy, Fluorescence ; Models, Genetic ; Plasmids ; genetics ; Polymerase Chain Reaction ; Thymidylate Synthase ; genetics ; metabolism ; Vibrio cholerae ; enzymology ; genetics ; metabolism

BACKGROUNDSeveral studies have evaluated the association between polymorphisms of thymidylate synthase (TS) and cancer risk in diverse populations but with conflicting results. By pooling the relatively small samples in each study, it is possible to evaluate the association using a meta-analysis.

METHODSA comprehensive search was conducted to identify all case-control studies on TS on a 28-bp tandem repeats in 5'untranslated region (5'UTR) and a 6-bp insertion (ins) and deletion (del) mutation in 3'UTR of the gene and cancer risk. Meta-analysis was conducted using a fixed and random effect model.

RESULTSOur meta-analysis on a total of 13 307 cancer cases and 18 226 control subjects from 37 published case-control studies showed no significant association between the risk of cancer and the 5'UTR 28-bp tandem repeats polymorphism (3R/3R vs. 2R/2R: OR = 1.06, 95%CI, 0.93 - 1.20) or the 3'UTR 6-bp ins/del polymorphism (del6/del6 vs. ins6/ins6: OR = 0.93, 95%CI, 0.81 - 1.08) with significant between-study heterogeneity. In the cancer type- and ethnic subgroup-stratification analyses, we did not find any association between TS polymorphisms and cancer risk either.

CONCLUSIONTS 5'UTR 28-bp tandem repeats and 3'UTR 6-bp ins/del polymorphisms may not be associated with cancer risk.

3' Untranslated Regions ; genetics ; 5' Untranslated Regions ; genetics ; Case-Control Studies ; Genetic Predisposition to Disease ; genetics ; Humans ; Neoplasms ; epidemiology ; genetics ; Polymorphism, Genetic ; genetics ; Tandem Repeat Sequences ; genetics ; Thymidylate Synthase ; genetics

OBJECTIVE: To analyze the impact of β-tubulin-III (TUBB3), thymidylate synthase (TS) and excision repair cross complementation group 1 (ERCC1) mRNA expression on chemoresponse and clinical outcome of patients with advanced gastric cancer treated with TXT/CDDP/FU (DCF) regimen chemotherapy. METHODS: The study population consisted of 48 patients with advanced gastric cancer. All patients were treated with DCF regimen palliative chemotherapy. The mRNA expressions of TUBB3, TS and ERCC1 of primary tumors were examined by multiplex branched-DNA liquid chip technology. RESULTS: The patients with low TUBB3 mRNA expression had higher response rate to chemotherapy than patients with high TUBB3 expression (P=0.011). There were no significant differences between response rate and TS or ERCC1 expression pattern. Median overall survival (OS) and median time to progression (TTP) were significantly longer in patients with low TUBB3 mRNA expression (P=0.002, P<0.001). TS or ERCC1 expression was not correlated with TTP and OS. In the combined analysis including TUBB3, TS and ERCC1, the patients with 0 or 1 high expression gene had better response rate, TTP and OS than the remaining patients (all P<0.001). Multivariate analysis revealed that ECOG (Eastern Cooperative Oncology Group)≥2 (HR=2.42, P=0.009) and TUBB3 (HR=2.34, P=0.036) mRNA expression significantly impacted on OS. CONCLUSION High TUBB3 mRNA expression is correlated with resistance to DCF regimen chemotherapy. TUBB3 might be a predictive and prognostic factor in patients with advanced gastric cancer treated with TXT-based chemotherapy. The combined evaluation of TUBB3, TS and ERCC1 expression can promote the individual treatment in advanced gastric cancer.
Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Biomarkers, Tumor ; metabolism ; DNA-Binding Proteins ; genetics ; metabolism ; Drug Resistance, Neoplasm ; Endonucleases ; genetics ; metabolism ; Humans ; RNA, Messenger ; genetics ; metabolism ; Stomach Neoplasms ; drug therapy ; genetics ; Thymidylate Synthase ; genetics ; metabolism ; Treatment Outcome ; Tubulin ; genetics ; metabolism

Individualized tailored therapy is a currently pursuing direction for improving the outcome of patients with colorectal cancer. Targeted therapy is the potential strategy to reach this goal by evaluating status of the presumed targets and their related effector molecules and by maximizing the efficacy of chemotherapeutic agents with less toxicity in individual patient. Numerous hurdles should be overcome, however, because therapeutic outcome can be affected by multiple components; tumor characteristics such as somatic mutations at the DNA, RNA, and protein levels; patient characteristics like germline genetic polymorphisms in enzymes linked to drug metabolism; and environmental factors that include diet and physical activity. Currently, large numbers of potential biomarkers have been proposed but have not yet accomplished supporting evidences for their routine usage in clinics. Therefore, clinical trials driven by molecular targets and relevant biomarkers for the understanding of the conflicting data are needed to make markers available in clinical practice.
Colorectal Neoplasms/*drug therapy/radiotherapy ; Combined Modality Therapy ; CpG Islands/genetics ; DNA Topoisomerases, Type I/genetics ; Humans ; Receptor, Epidermal Growth Factor/genetics ; Thymidylate Synthase/genetics ; Tumor Markers, Biological/*genetics

BACKGROUNDThymidylate synthase (TS) is a key regulatory enzyme for de novo DNA synthesis. TS activity is also an important determinant of the response to chemotherapy with fluoropyrimidine prodrugs, and its expression may be affected by gene polymorphisms. In this study, we investigated the associations between polymorphisms of the TS gene and its protein expression, and the implications on the efficacy of 5-fluorouracil (5-FU) in pancreatic cancer cells.

METHODSGenotypes based on the 28-bp TS tandem repeat for pancreatic cell lines were determined by electrophoretic analysis of PCR products. A single nucleotide polymorphism (SNP) at nucleotide 12 of the second 28-bp repeat of the 3R allele was determined by nucleotide sequencing. The chemosensitivity of pancreatic carcinoma cells to 5-FU in vitro was evaluated using Cell Counting Kit-8 (CCK-8). TS protein expression was analyzed by Western blotting.

RESULTSSeven pancreatic carcinoma cell lines had different genotypes in terms of the 28-bp TS tandem repeat, as follows: homozygous 2R/2R (T3M4 and BxPC-3 cells), heterozygous 2R/3R (AsPC-1, Capan-1, and SU86.86), and homozygous 3R/3R (PANC-1 and COLO357). The optical density ratio of genotypes 3R/3R, 2R/2R and 2R/3R was 1.393 ± 0.374, 0.568 ± 0.032 and 0.561 ± 0.056, respectively. Cells with the 2R/3R or 3R/3R genotypes were further analyzed for the G to C SNP at nucleotide 12 of the second 28-bp repeat of the 3R allele, yielding heterozygous 2R/3Rc (AsPC-1, Capan-1, and SU86.86), homozygous 3Rg/3Rg (COLO357) and homozygous 3Rc/3Rc (PANC-1). The optical density ratio of homozygous 3Rg/3Rg cells and homozygous 3Rc/3Rc cells was 1.723 ± 0.062 and 1.063 ± 0.134, respectively, and this difference was statistically significant (P < 0.05). Cells with the 2R/2R and 2R/3R genotypes of TS were hypersensitive to 5-FU in vitro as compared with those with the 3R/3R cells.

CONCLUSIONSPolymorphisms in the TS gene influenced its protein expression and affected sensitivity of 5-FU in seven pancreatic cancer cell lines. Cells with the 3R/3R genotype had higher TS protein expression than the 2R/2R or 2R/3R genotypes. Cells of the 3R/3R genotype with high TS protein expression were shown lower 5-FU sensitivity than cells with the 2R/2R or 2R/3R genotypes. These data warrant large-scale clinical studies to assess the role of polymorphisms in the TS gene on its protein expression and chemosensitivity to 5-FU in pancreatic cancer.

Blotting, Western ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Fluorouracil ; pharmacology ; Humans ; Minisatellite Repeats ; genetics ; Pancreatic Neoplasms ; genetics ; Polymerase Chain Reaction ; Polymorphism, Genetic ; genetics ; Polymorphism, Single Nucleotide ; genetics ; Thymidylate Synthase ; genetics

BACKGROUND/AIMS: Thymidylate synthase (TS) is a target enzyme of 5-fluorouracil (5-FU) and has a polymorphic 28 bp tandem repeated sequence. TS enhancer region (TSER) polymorphism has been associated with the efficacy of 5-FU-based chemotherapy in colon cancer. Methylenetetrahydrofolate reductase (MTHFR) plays a central role in converting folate to methyl donor for DNA methylation. The aim of this study was to determine the clinical value of TSER and MTHFR polymorphism in gastric cancer. METHODS: From October, 1995 to February, 2002, 40 gastric cancer patients underwent operation and 25 patients among those patients have received postoperative 5-FU-based chemotherapy (5-FU (+) group). Peripherial blood were sampled for TSER and MTHFR genotype analysis by PCR amplification of genomic DNA. The survival of patients according to TSER and MTHFR polymorphism were compared. RESULTS: We observed a longer survival in stage II than stage III of the patients (p=0.0037). However, the TSER and MTHFR C677T polymorphisms were not associated with better survival of gastric cancer patients as well as combined TSER and MTHFR genotypes with 5-FU chemotherapy. CONCLUSIONS: The TSER and MTHFR genotypes are not effective markers for tumor sensitivity to 5-FU-based chemotherapy in Korean gastric cancer patients after curative resection. These results may suggest further large-scale study about TSER and MTHFR polymorphism for the prediction of efficacy of 5-FU-based chemotherapy in gastric cancer in Korea.
Aged ; Antimetabolites, Antineoplastic/*therapeutic use ; Drug Screening Assays, Antitumor ; Female ; Fluorouracil/*therapeutic use ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2)/*genetics ; Middle Aged ; *Polymorphism, Genetic ; Stomach Neoplasms/*drug therapy/genetics/mortality ; Survival Rate ; Thymidylate Synthase/*genetics