Relationship between thymidylate synthase and p53 and response to FEC versus taxane adjuvant chemotherapy for breast carcinoma.

Many drugs can be used for adjuvant therapy of breast cancer, including anthracyclines, cyclophosphamide, 5-fluorouracil (5-fU) and, recently, taxanes (TXT) have shown promising results. 5-FU blocks thymidylate synthase (TS) which cross-links p53 mRNA, inhibiting its synthesis. TS overexpression is one of the main mechanisms involved in 5-FU drug resistance.

Analysis of the thymidylate synthase gene structure in colorectal cancer patients and its possible relation with the 5-Fluorouracil drug response.

Thymidylate synthase (TS) catalyzes methylation of dUMP to dTMP and it is the target for the 5-Fluorouracil (5-FU) activity. Barbour et al. showed that variant structural forms of TS in tumour cell lines confer resistance to fluoropyrimidines.

Differing expression of metalloprotease and of adhesion molecules in signet-ring cell and intestinal colorectal carcinoma.

Background: Pure signet-ring cell colorectal carcinoma (SRCC) is an infrequent and highly malignant histological variant of colorectal cancer (CRC), while it is present as a histological component in colorectal carcinomas more frequently.

Materials And Methods: The aim of this work was to widen the knowledge of the biological factors involved in the pathogenesis and aggressiveness of SRCC by the identification and evaluation of possible molecular abnormalities. By means of immunohistochemistry the expression of the proteolytic degradation enzyme matrix metalloprotease (MMP)-1, that is a collagenase specifically degrading collagens I, II, III and of the adhesion proteins E-cadherin, beta-catenin and fibronectin which are usually involved in the carcinogenesis of conventional colorectal tumours was investigated.

The effect of CYP3A5 and ABCB1 single nucleotide polymorphisms on tacrolimus dose requirements in Caucasian liver transplant patients.

Background: Tacrolimus is a substrate of cytochrome P-450 (CYP) 3A enzyme and of the drug transporter ABCB1. We have investigated the effects of possible relevant CYP3A5 and ABCB1 single nucleotide polymorphisms (SNPs) present in both donors and recipients on tacrolimus blood levels achieved in a population of 32 Caucasian liver transplant patients.

Material/methods: At 1, 3 and 6 months after transplantation, tacrolimus doses (mg/kg/day) and trough blood levels (C(0)) were determined.

Different expression of thymidylate synthase in primary tumour and metastatic nodes in breast cancer patients.

Background: To date an accurate evaluation of predictive markers in breast cancer is mainly conducted at the primary site, although the main goal of the adjuvant therapy is the control of micrometastases. Adjuvant therapy drugs need a high proliferative cell rate to be effective. The proliferating activity can be evaluated by the Ki-67 marker and even by thymidylate synthase (TS), a cell cycle enzyme present in proliferating cells.

Lymph node metastases displaying lower Ki-67 immunostaining activity than the primary breast cancer.

Unlabelled: The aim of the study was to verify by Ki-67 immunostaining if any difference exists in the cell proliferating fraction between primary breast tumors (PTs) and matching positive axillary lymph nodes (ALNs).

Patients And Methods: Immunohistochemistry with the monoclonal antibody against Ki-67 was performed in 160 node-positive breast carcinomas and in their respective lymph node metastases.

Results: An increase of Ki-67 immunoreactive cells in ALN compared with that of PTs was observed in 84% of cases (ALN: mean 17%, PTs: mean 8%; p < 0.

Difference in Ki67 and thymidylate synthase expression in primary tumour compared with metastatic nodes in breast cancer patients.

Breast cancer is a heterogeneous disease, so therapeutic predictive biological markers need to be identified. To date an accurate evaluation of predictive markers is mainly done at the primary site; however, the main goal of adjuvant therapy for breast cancer is the control of micrometastases. The aim of this study is to assess as therapeutic and/or prognostic marker, the proliferation status of primary tumors and involved nodes as measured by Ki67 and thymidylate synthase (TS) expression, in 30 breast cancer node positive patients.

Antitumor effects of the novel NF-kappaB inhibitor dehydroxymethyl-epoxyquinomicin on human hepatic cancer cells: analysis of synergy with cisplatin and of possible correlation with inhibition of pro-survival genes and IL-6 production.

We tested the novel NF-kappaB inhibitor dehydroxymethylepoxyquinomicin (DHMEQ) in the hepatic cancer (HCC) HepG2, HA22T/VGH and HuH-6 cells. The sensitivity to the cell growth inhibitory and apoptotic effects of the agent increased along with the levels of constitutively activated NF-kappaB, which were low in HepG2 and higher in HA22T/VGH and HuH-6. In HA22T/VGH, DHMEQ exhibited synergy with cisplatin.

Thymidylate synthase gene promoter polymorphisms are associated with TSmRNA expressions but not with microsatellite instability in colorectal cancer.

Background: Microsatellite instability (MSI) is a biological characteristic of most tumours, being involved in 85% of hereditary non-polyposis colorectal cancer (HNPCC). It also occurs in 10-15% of sporadic colorectal cancers (CRC). HNPCC appears to be caused by germline mutations in mismatch repair (MMR) genes, which are responsible for repairing single base-pair mismatches.

Clinical relevance of thymidylate synthase expression in the signet ring cell histotype component of colorectal carcinoma.

Thymidylate Synthase (TS) is the key enzyme for DNA synthesis pathways and is inhibited by 5-fluorouracil (5FU). The aim of this work was to study TS expression and the proliferation rate in the different histological types of colorectal carcinoma (CRC). 50 patients with CRC were included in this study and evaluated immunohistochemically using the monoclonal antibodies, TS106 and Ki67.

Thymidylate synthase polymorphism and microsatellite instability: association in colorectal cancer.

5-Fluorouracil (5FU) is the main drug used for the treatment of colorectal cancer (CRC) and Thymidilate Synthase (TS) is its target enzyme. TS gene has regulatory tandemly repeated sequences in its 5' and 3'untraslated region (5'-3' UTR). CRC often shows a kind of genomic instability called Microsatellite Instability (MSI) that is associated with TS levels and survival.

Associations between polymorphisms in the thymidylate synthase gene, the expression of thymidylate synthase mRNA and the microsatellite instability phenotype of colorectal cancer.

Microsatellite instability (MSI) is a characteristic feature of up to 15% of colorectal cancers (CRC) and is associated with better response to adjuvant chemotherapy with 5-fluorouracil (5-FU). In this study we have investigated the association between the MSI status and the mRNA expression as well as the polymorphisms of the cellular target of 5-FU therapy, thymidylate synthase. Polymorphisms in the 3'- and the 5'-UTR of the TS gene were determined by a PCR assay in 53 colorectal cancer tissues.

Correlation between GP-170 expression, prognosis, and chemoresistance of superficial bladder carcinoma.

Purpose: To study GP-170 in superficial bladder cancer at initial diagnosis and at recurrence and to evaluate if intravesical chemoprophylaxis modifies the expression of GP-170 in tumor recurrences.

Materials And Methods: GP-170 was retrospectively assessed in 160 patients affected by primary superficial transitional cell carcinoma of the bladder and followed for up to 10 years. Eighty-four patients (52.

Does P-glycoprotein-170 expression predict for chemoresistance in transitional cell carcinoma of the bladder?

Introduction: The glycoprotein P-170, causing drug efflux from the cells, may represent at least one cause of resistance to most drugs used in intravesical chemotherapy of superficial bladder cancer.

Materials And Methods: GP-170 was retrospectively assessed in 60 patients affected by superficial transitional cell tumours of the bladder. It was assessed by immunohistochemistry in a semiquantitative way by the intensity of staining and by the percentage of positive cells.

In vitro generation of cytotoxic T lymphocytes against HLA-A2.1-restricted peptides derived from human thymidylate synthase.

5-Fluorouracil (5-FU) is a pyrimidine antimetabolite active against colorectal carcinoma and other malignancies of the digestive tract. Over-expression or mutation of thymidylate synthase (TS), the target enzyme of the 5-FU metabolite, 5-fluorodeoxyuridine monophosphate, is strictly correlated with cancer cell resistance to 5-FU. On this basis we investigated whether TS is a potential target for active specific immunotherapy of human colon carcinoma, which acquires resistance to 5-FU.

Failure of detection of the tyrosine to histidine substitution at the residue 33 of thymidylate synthase in human colorectal cancer. A preliminary study.

Structural changes in the macromolecular targets of pharmacological agents can result in alterations in the efficacy of these agents. In previous studies Berger et al. (1) identified a variant structural form of thymidylate synthase (TS) that is associated with relative resistance to 5-fluoro-2'-deoxyuridine, in a human colonic tumor cell line.

The role of thymidylate synthase levels in the prognosis and the treatment of patients with colorectal cancer.

Inhibition of Thymidylate Synthase (TS) by the 5-Fluorouracil (5Fu) active metabolite Fluoro-deoxy-uridine-monophosphate (FdUMP) is considered to be the main mechanism of action of 5Fu. TS level from tumors and normal mucosa of 62 untreated patients who underwent surgery for primary colorectal adenocarcinoma was performed. The aim of this study was to evaluate the possibility of considering the TS level as a prognostic factor of the disease.

Thymidylate synthase level and DNA-ploidy pattern as possible prognostic factors in human colorectal cancer: a preliminary study.

5-Fluorouracil is the drug chosen for the treatment of patients with advanced colorectal carcinoma; its major site of action is thymidylate synthase (TS), resulting in pronounced and prolonged inhibition of DNA synthesis. The aim of this study was to evaluate the possibility of considering TS level in human colorectal carcinomas of previously untreated patients (pts) as a prognostic factor. Our data demonstrate that there is no association with age, sex, tumor site and tumor size; however, there is a relationship between TS levels and staging: in fact, the TS values are higher (P < 0.

Morphological changes in the hearts of CD1 mice following chronic treatment with doxorubicin and lonidamine.

CD1 female mice were treated with doxorubicin (DXR, 5 mg/Kg i.v.) once a week for eight weeks or with lonidamine (LND, 100 mg/Kg i.

Influence of mitoxantrone on the syntheses of DNA and proteins of mouse tissues.

In view of the structural similarity of mitoxantrone to anthracyclines and its ability to intercalate into DNA, we studied its influence on the synthetic processes of DNA and proteins in CD-1 mice tissues. By studying at the DNA level the impairment of 3H-thymidine incorporation and its return to normal, it was found that bone marrow and spleen showed similar behavior, i.e.

Ameliorative effects of ICRF-187 [(+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane] on the cardiotoxicity induced by doxorubicin or by isoproterenol in the mouse.

CD 1 female mice were treated with Doxorubicin (5 mg/Kg i.v.) once a week for 8 weeks or with Isoproterenol (20 mg/Kg s.

Morphological changes and catalase activity in the hearts of CD 1 mice following acute starvation or single doses of doxorubicin, epirubicin or mitoxantrone.

The cardiac morphology of CD 1 mice undergoing two different schedules of acute (5 day) starvation and that of animals treated with a single dose (15 mg/kg i.p.) of doxorubicin, epirubicin or mitoxantrone were studied by light microscopy.

The role of histamine in doxorubicin and teniposide-induced cardiotoxicity in dog and mouse.

In previous studies we reported that teniposide (VM26) induced acute cardiac effects in dogs seem to be related to a release of histamine and that a prior treatment with chlorpheniramine, an H1 histamine blocker, prevents the onset of this phenomenon. Since histamine and other vasoactive substances also seem to be involved in doxorubicin (DXR)-induced acute cardiac effects, experiments were undertaken in the aim to prevent, as in the case of VM26, the onset of this phenomenon by administering chlorpheniramine. Since DXR-induced chronic cardiomyopathy also seems to be related to the same mechanisms involved in the onset of acute cardiac effects induced by this drug, additional studies were carried out to investigate whether a long-term treatment with VM26 could induce in mouse alterations of cardiac morphology similar to those of DXR.