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. Enough p53 mutations can confer resistance to chemotherapy using anthracyclines and 5-FU, while are associated with improved responses to TXT. The aim of this study was to examine the TS and p53 levels in tumor samples and to compare the efficacy of FEC (5-FU, epirubicin, cyclophosphamide) and TXT chemotherapy in a group of patients wit…

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. Our data show that the genotype 2R/2R (homozygosity for 2 tandem repeat sequences in the 5''UTR) is more frequently associated with MSI+ and lower TS levels. More over we did not find any significant association between the 2R/3R (heterozygosity for 2 and 3 tandem repeat sequences in the 5''UTR) and 3R/3R (homozygosity f…

Relationship between thymidylate synthase expression and p53 levels with the treatment of cyclophsphamide, methotrexate, 5-fluorouracil chemotherapy ( CMF)versus docetaxel ( TXT) in locally advanced carcinoma of the breast

10546 Background: Adjuvant chemotherapy is used in the treatment of breast carcinoma independently of axillar node involvement. Different drug combinations such as CMF, FAC, FEC are still used; recently new drugs such as TXT (NEJM 332:1004,1997) show activity and are used also in adjuvant chemotherapy. 5 Fluorouracil (5Fu), a drug involved in main therapeutic regimens, blocks Thymidylate Synthase (TS), an enzyme involved in the DNA synthesis. TS not only links its own mRNA, but also p53 mRNA, inhibiting post transcriptional p53 protein synthesis. TS protein overexpression (Cancer Res 55:1407,1995), and/or its absence (Cancer Res 61:1421,2001) are some of the main mechanisms of 5-Fu drug re…

Antitumor effects of the novel NF-κB 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. In the same cells, DHMEQ exerted dose-dependent decreases in the nuclear levels of activated NF-kappaB and attenuated NF-kappaB activation by cisplatin. It down-regulated Bcl-XL mRNA in a dose-dependent manner and up-regulated that of Bcl-XS. It also decreased interleukin 6 (IL-6), NAIP and, …

Effects of verapamil and N-acetylcysteine on doxorubicin or isoproterenol cardiotoxicity in mice

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 ABCBl. We have investigated the effects of possible relevant CYP3A5 and ABCBl 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 (C0) were determined. Polymerase chain reaction followed by restriction fragment length polymorphism analysis was used for gen-otyping CYP3A5*3 [6986A>G] as well as ABCBl at exons 21 [2677G>T] and 26 [3435C>T]. Results:87.5…

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

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. 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 (52.5%) recurred after transurethral resection (TUR). Adjuvant intravesical chemotherapy after TUR was adopted in 52 patients. The correlations between GP-170 and G-grade, T-category, risk of recurrence and of progression, and adoption of adjuvant intravesical chemotherapy were investigated. The correlations between variations…

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 2H-thymidine incorporation and its return to normal, it was found that bone marrow and spleen showed similar behavior, i.e., a rapid return to normal, which occurred before bone marrow cell number and spleen weight returned to basal values. At the cardiac level, the incorporation values of precursors into DNA, reduced by treatment with mitoxantrone, came back very slowly to the control ones. Hepatic DNA showed a lower sensitivity to mitoxant…

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. TS mRNA was quantified by real-time RT-PCR. Data were correlated with the MSI phenotype. There was neither a significant correlation between the polymorphisms in the TS gene and the MSI phenotype n…

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

Abstract 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. MSI is also associated with a better response of CRC to adjuvant chemotherapy with fluoropyrimidines. We investigated any relationship between the MSI status and the TSmRNA expression, the polymorphisms of 5-Fluorouracil (5-FU cellular target, the enzyme thymidylate synthase (TS) and TS expression evaluated by…

Matrix metalloproteinase-1 is differentially expressed in signet ring cell, and intestinal colorectal carcinomas histotypes

14564 Background: Signet ring cell colorectal carcinoma ( SRCC) pure is an infrequent and highly malignant variant of colorectal cancer, while this histological component is present in 30% of all colorectal carcinomas. In our previous studies we compared the E- Cadherin, β- Catenin, Fibronectin, Ki 67 and Thymidylate Synthase (TS) expression of SRCC, the intestinal type of colorectal carcinoma (ICRC) to try to explain the pathogenesis, the aggressiveness and the low 5 Fluorouracil (5FU) responsiveness of these tumours. We found that all SRCCs had very low levels of all markers and were in the post- mitotic phase of the cell cycle. To understand their high metastatic capability we assessed …

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. TS is the main target of 5-fluorouracil (5-FU) activity, and its overexpression is one of the mechanisms of 5-FU drug resistance; however, in some studies its a…

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. We planned to perform the whole TS gene structure by means of sequencing techniques in human colorectal cancer (CRC) samples to try to identify the presence of any possible TS variant form that could be responsible of fluoropyrimidines drug resistance and of the worse prognosis. We performed the TS-DNA gene sequence in 68 CRC from patients of A, B, and C Dukes' stages and different histological grade, but we did not find any mutation in the TS-DNA str…

Clinical relevance of thymidylate syntetase 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. 20 tumours were of the intestinal type, 15 cases were signet ring cell carcinoma (SRCCs) and 15 cases were "mixed-type", with at least two different histological components. Intestinal and mucinous histotypes were positive for TS and Ki67, while "signet ring cell" samples were negative or showed only weak and…

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 H, 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 …

Dissimilar effects of doxorubicin and isoproterenol on morphology, H2O2 content and catalase activity in mouse heart

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. In this study the TS levels in primary tumours were compared to those of their metastases. PATIENTS AND METHODS: The TS expression and Ki-67 were evaluated by means of immunohistochemistry in 80 primary breast tumours (PTs) and in their matched axillary metastati…

Influence of Pharmacokinetic Variations on the Pharmacological Properties of Adriamycin

Whenever it appears impossible to modify the chemical structure of drugs with a high and established therapeutic activity but a low chemotherapeutic index, pharmacological research has to find other ways of improving the chemotherapeutic index. This problem is particularly important in the case of antitumor drugs, thus justifying research into the most suitable choice of dosage and routes of administration, as well as into the pharmacological associations which enable tumor cells to be hit at various stages of the reproductive cycle. Alternatively, the therapeutic index could be improved by the use of antagonistic compounds (like, for example, methotrexate and folinic acid) which act upon t…