Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P04637 (p53)
77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to review gene alterations associated with drug responses in vitro to identify candidate genes for predictive chemosensitivity testing, we selected from literature genes fulfilling at least one of the following criteria for the definition of 'in vitro chemosensitivity associated gene': (i) alterations of the gene can be identified in human solid tumor cell lines exhibiting drug-induced resistance; (ii) transfection of the gene induces drug resistance; (iii) down-regulation of the gene increases the drug sensitivity. We then performed Medline searches for papers on the association between gene alterations of the selected genes and chemosensitivity of cancer cell lines, using the name of the gene as a keyword. A total of 80 genes were identified, which were categorized according to the protein encoded by them as follows: transporters (n = 15), drug targets (n = 8), target-associated proteins (n = 7), intracellular detoxifiers (n = 7), DNA repair proteins (n = 10), DNA damage recognition proteins (n = 2), cell cycle regulators (n = 6), mitogenic and survival signal regulators (n = 7), transcription factors (n = 4), cell adhesion-mediated drug resistance protein (n = 1), and apoptosis regulators (n = 13). The association between the gene alterations and chemosensitivity of cancer cell lines was evaluated in 50 studies for 35 genes. The genes for which the association above was shown in two or more studies were those encoding the major vault protein, thymidylate synthetase, glutathione S-transferase pi, metallothionein, tumor suppressor p53, and bcl-2. We conclude that a total of 80 in vitro chemosensitivity associated genes identified in the literature are potential candidates for clinical predictive chemosensitivity testing.
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PMID:Genes regulating the sensitivity of solid tumor cell lines to cytotoxic agents: a literature review. 1759 44

Recent studies have demonstrated that tegafur-uracil (UFT) is useful for the adjuvant treatment of various types of cancers. To determine whether nucleoside metabolizing enzymes could be used to predict the response to UFT treatment in women with primary breast cancer, we retrospectively analyzed archived tumor tissue samples obtained from the 3rd Adjuvant Chemo-Endocrine Therapy for Breast Cancer (ACETBC) study, in which adjuvant treatment with tamoxifen (TAM) plus UFT for 2 years was compared with TAM alone for 2 years. Samples of tumor tissue were obtained from 192 premenopausal women with node-positive invasive breast cancer. The tissue samples were examined immunohistochemically to study the expression of thymidylate synthase (TS), thymidine phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD), as well as the expression of Her2 and p53. In patients with TS-positive tumors, the risk of relapse was significantly lower in the tamoxifen plus UFT group than in the tamoxifen alone group. After 2 years, however, there was a trend towards a decrease in the relative predictive value (RPV) of TS with time. No relationship to outcome was detected for TP or DPD. Expression of Her2 or p53 was a significant prognostic indicator in the tamoxifen alone group. TS, but not TP or DPD, may be a useful predictor of response to UFT therapy. After 2 years, the RPV of TS decreased with time, suggesting that 2 years of treatment with oral fluorouracil derivatives may be inadequate. Further studies are required to investigate this possibility.
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PMID:Predictive implications of nucleoside metabolizing enzymes in premenopausal women with node-positive primary breast cancer who were randomly assigned to receive tamoxifen alone or tamoxifen plus tegafur-uracil as adjuvant therapy. 1778 23

We analysed the expression of microsatellite instability, p53, p21, vascular endothelial growth factor and thymidylate synthase (TS) in pretreatment biopsy specimens from 57 locally advanced rectal cancers. The aim of the study was to correlate the expression of these markers with pathological response. Nineteen patients were treated with preoperative concomitant radiotherapy (RT) and fluorouracil/oxaliplatin-based chemotherapy (RCT), while 38 had RT alone. Pathological complete remission (pCR) and microfoci residual tumour (micR) occurred more frequently in patients treated with RCT (P=0.002) and in N0 tumours (P=0.004). Among patients treated with RCT, high TS levels were associated with a higher response rate (pCR+micR; P=0.015). No such correlation was found in the RT group. The other molecular factors were of no predictive value. Multivariate analysis confirmed a significant interaction between nodal status and the probability of achieving a pathological response (P=0.023) and between TS expression and treatment, indicating that a high TS level is predictive of a higher pathological response in the RCT subset (P=0.007). This study shows that lymph node status is the most important predictive factor of tumour response to preoperative treatment. Thymidylate synthase expression assessed immunohistochemically from pretreatment tumour biopsies may be a useful predictive marker of rectal tumour response to preoperative RCT.
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PMID:Biological predictive factors in rectal cancer treated with preoperative radiotherapy or radiochemotherapy. 1808 84

Intracellular supply of dTTP is a highly regulated process and has been a key target for chemotherapeutic drug development. Thymidylate kinase (TMPK) is the key enzyme for dTTP formation in both de novo and salvage pathways. In this study, we used lentiviral-based small hairpin RNA to silence TMPK expression in p53(+/+) and p53(-/-) HCT-116 colon cancer cells. This approach was sufficient to decrease the dTTP pool gradually without affecting p53 expression and generating cytotoxicity. TMPK knockdown significantly increased doxorubicin sensitivity dramatically in p53-proficient, p53-null HCT-116, and LoVo colon cancer cells. The decrease in the dTTP pool using this approach augmented the DNA damage response and enhanced apoptotic induction after exposure to low-dose doxorubicin, leading to cell death. In contrast, silencing of thymidylate synthase which blocks the de novo pathway was incapable of sensitizing p53-null HCT-116 cells to doxorubicin-induced apoptosis because of the compensation by the salvage pathway. Our results suggest the lentiviral delivery of small hairpin RNA targeting TMPK in combination with a low dose of doxorubicin as a new approach to kill colon cancer cells regardless of p53 status.
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PMID:Synthetic lethality by lentiviral short hairpin RNA silencing of thymidylate kinase and doxorubicin in colon cancer cells regardless of the p53 status. 1841 51

d-Allose is a novel anti-tumor monosaccharide that causes cell growth inhibition, specifically of the cancer cells, by inducing the tumor suppressor gene thioredoxin interacting protein (TXNIP). The commonly used anti-tumor drug, 5-fluorouracil (5-FU), blocks the cell cycle by inhibiting thymidylate synthase, and is also known to induce TXNIP gene expression. In this study, we examined the synergistic effect of d-allose and 5-FU and the role of TXNIP on cancer cell growth. The treatment of HuH-7 cells with d-allose or 5-FU inhibited the cell growth in a dose-dependent manner (75.2+/-2.7% with 50 mM d-allose and 66.1+/-2.7% with 0.5 mug/ml 5-FU) and d-allose enhanced the anti-tumor effect of 5-FU (55.3+/-1.1 %). TUNEL analysis did not show any evidence of apoptosis with either d-allose or 5-FU treatment. 5-FU suppressed the expression of p27(kip1), p53, and cyclin E, whereas d-allose induced p53 and reduced cyclins D, A, and E. The expression of p27(kip1) remained unchanged by d-allose at transcriptional level, but increased at the protein level suggesting an increase in protein stability by TXNIP. d-Allose and to a lesser extent 5-FU induced TXNIP expression significantly (808.4+/-122.9% and 186.8+/-32.9%, respectively) and the combination of both further enhanced TXNIP expression. As d-allose has no known side effects on normal cells, the combination of d-allose and 5-FU might be a potent candidate for cancer therapy.
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PMID:Rare sugar D-allose enhances anti-tumor effect of 5-fluorouracil on the human hepatocellular carcinoma cell line HuH-7. 1893

The major determinants of 5-flurouracil (5-FU) response would seem, based on accumulated literature, to be thymidylate synthase (TYMS, TS) expression levels, TS gene modifications, and TP53 status. We tested 5-FU sensitivity in yeast and human cancer cell models in which TS or TP53 alleles and expression were varied. Polymorphic TS tandem repeat status, TS expression levels reported, TS intragenic mutations, and TP53 status in outbred and experimental cancer cell lines did not predict 5-FU sensitivity or resistance. Novel observations included a dose-resistant persistence of unbound TS protein in many cancers and, upon 5-FU treatment of the colon cancer cell line, HCT116, evidence of allelic switching favoring transcripts of the mutant TS allele. The reported alleles having an intragenic mutation could not be causally associated with major degrees of 5-FU sensitivity. In yeast, TS protein was altered upon treatment with FdUMP, but 5-FU toxicity seemed to be largely RNA-based, being rescued by uridine rather than by thymidine. Cancer cell lines were also rescued from 5-FU toxicity with uridine rather than thymidine. Additionally, a TS (CDC21) knockout yeast strain, obviating any potential role for TS protein as a target, was hypersensitive to 5-FU. When denatured proteins from cancer cells treated with radiolabeled 5-FU were labeled, species with alternative molecular weights other than TS were visualized, providing further evidence for alternative 5-FU protein targets. These data emphasize that TS and TP53 status do not consistently explain the variance in responses of fluoropyrimidine-treated cancer cells, in part due to RNA-based toxicity.
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PMID:Limits to thymidylate synthase and TP53 genes as predictive determinants for fluoropyrimidine sensitivity and further evidence for RNA-based toxicity as a major influence. 1915 91

We evaluated the usefulness of the level of thymidylate synthase(TS)and dihydropyrimidine dehydrogenase(DPD) activity as prognostic factors and indicators for selection of chemotherapy regimens. Between November 1997 and March 1999, fifty-seven patients with stages I - IIIa primary breast cancer were registered. Using recurrence risk categories, they were classified into TAM monotherapy, TAM+oral 5-FU, and TAM+CMF groups(each were standard regimens at the time), and underwent postoperative adjuvant chemotherapy. The relationship between prognosis and the TS level and DPD activity, in addition to conventional risk factors, was examined. The recurrence-free survival time curve showed significant differences when stratified by tumor diameter, ER expression, and TS levels, but not by menopausal status, nodal status, surgical method, p53 expression, DPD activity, or HER2 expression. These results suggest that the TS level is useful as a prognostic factor for breast cancer.
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PMID:[Clinical significance of intratumoral TS levels and DPD activity in breast cancer]. 1929 64

Despite recent therapeutic advances, the response rates to chemotherapy for patients with metastatic colon cancer remain at approximately 50% with the fluoropyrimidine, 5-fluorouracil (5-FU), continuing to serve as the foundation chemotherapeutic agent for the treatment of this disease. Previous studies have demonstrated that overexpression of thymidylate synthase (TS) is a key determinant of resistance to 5-FU-based chemotherapy. Therefore, there is a significant need to develop alternative therapeutic strategies to overcome TS-mediated resistance. In this study, we demonstrate that the histone deacetylase inhibitors (HDACi) vorinostat and LBH589 significantly downregulate TS gene expression in a panel of colon cancer cell lines. Downregulation of TS was independent of p53, p21 and HDAC2 expression and was achievable in vivo as demonstrated by mouse xenograft models. We provide evidence that HDACi treatment leads to a potent transcriptional repression of the TS gene. Combination of the fluoropyrimidines 5-FU or FUdR with both vorinostat and LBH589 enhanced cell cycle arrest and growth inhibition. Importantly, the downstream effects of TS inhibition were significantly enhanced by this combination including the inhibition of acute TS induction and the enhanced accumulation of the cytotoxic nucleotide intermediate dUTP. These data demonstrate that HDACi repress TS expression at the level of transcription and provides the first evidence suggesting a direct mechanistic link between TS downregulation and the synergistic interaction observed between HDACi and 5-FU. This study provides rationale for the continued clinical evaluation of HDACi in combination with 5-FU-based therapies as a strategy to overcome TS-mediated resistance.
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PMID:Histone deacetylase inhibitors suppress thymidylate synthase gene expression and synergize with the fluoropyrimidines in colon cancer cells. 1938 49

The esophageal squamous cell carcinoma is multifactorial disease involving genetic and environmental factors. The paper presents most important human data on the polymorphisms of selected genes that have been linked with higher risk of the neoplasm. The most widely studied group were genes encoded molecules engaged in biotransformations of xenobiotics, in particular potential carcinogens, like alcohol (ADH2) and aldehyde (ALDH2) dehydrogenases, various isoenzymes of cytochrome P450 (CYP1A1, CYP2E1) and glutathione S-transferase (GSTM1, GSTT1, GSTP1). High interest was also put for polymorphism in DNA repair genes, i.e., OGG1, XRCC1, XPD, XPG and MGMT as well as genes associated with nucleotide biosyntesis like methylenotetrahydrofolate reductase and thymidylate synthase and in control of cell cycle and apoptosis e.g., p53, Fas, FasL or TNF. Furthermore, it was revealed that predisposition to cancer in certain individual could be determined by coexistence of unprofitable allele of a few genes. Introduction of genetic screening test allows effective, purpose-oriented methods of prevention and in patients suffered from the cancer--application of optimal therapy and minimization of side-effects.
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PMID:[Genetic base of esophageal squamous cell carcinoma susceptibility]. 1938 10

Locally advanced rectal cancer (LARC) is currently treated with neoadjuvant chemoradiation. Although approximately 45% of patients respond to neoadjuvant therapy with T-level downstaging, there is no effective method of predicting which patients will respond. Molecular biomarkers have been investigated for their ability to predict outcome in LARC treated with neoadjuvant chemotherapy and radiation. A literature search using PubMed resulted in the initial assessment of 1,204 articles. Articles addressing the ability of a biomarker to predict outcome for LARC treated with neoadjuvant chemotherapy and radiation were included. Six biomarkers met the criteria for review: p53, epidermal growth factor receptor (EGFR), thymidylate synthase, Ki-67, p21, and bcl-2/bax. On the basis of composite data, p53 is unlikely to have utility as a predictor of response. Epidermal growth factor receptor has shown promise as a predictor when quantitatively evaluated in pretreatment biopsies or when EGFR polymorphisms are evaluated in germline DNA. Thymidylate synthase, when evaluated for polymorphisms in germline DNA, is promising as a predictive biomarker. Ki-67 and bcl-2 are not useful in predicting outcome. p21 needs to be further evaluated to determine its usefulness in predicting outcome. Bax requires more investigation to determine its usefulness. Epidermal growth factor receptor, thymidylate synthase, and p21 should be evaluated in larger prospective clinical trials for their ability to guide preoperative therapy choices in LARC.
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PMID:Biomarkers for response to neoadjuvant chemoradiation for rectal cancer. 1948 Sep 68


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