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Biomedical subjects

S Tommasi

Publications and source records attributed to S Tommasi.

At least 19 recordsLinked to original sources
PubMed2005

BRCA1 mutations and polymorphisms in a hospital-based consecutive series of breast cancer patients from Apulia, Italy.

INTRODUCTION: Hereditary breast cancer has been partly attributed to germline mutations in the BRCA1 gene that are deleterious for BRCA1 protein activity. This paper analyzes the incidence and characteristics of detectable BRCA1 mutations and polymorphisms in a hospital-based consecutive series of breast cancer patients from southern Italy to investigate the incidence and the association of these molecular alterations with breast cancer biology and family history. METHODS: One hundred cases with familial characteristics were selected from a consecutive series of 511 patients with a first diagnosis of breast cancer. DNA from peripheral blood was screened for whole BRCA1 gene mutations utilizing dHPLC as a pre-screening analysis and automatic DNA sequencing for the identification of specific alterations. RESULTS: In the overall series of 511 patients, 100 had a family history of breast cancer and were investigated for BRCA1 mutations. Two types of BRCA1 mutations were identified, 5382insC in six cases and 4566delA in one case. The 5382insC mutation was present in two out of six cases with ovarian cancer while 4566delA in one case of male cancer. The most frequent missense polymorphisms were E1038G, P871L, K1183R in exon 11, S1613G, M1652I in exon 16 and D1778G in exon 22. Confirming what found in previous studies, patients in whom pathological BRCA1 mutations were detected had early-onset breast cancer (p=0.05), positive nodal status (p=0.05), lower ER (p=0.02) and PgR (p=0.01) content. Interestingly, the K1183R polymorphism and, less strongly, S1613G polymorphism were associated to mutational risk (K1183R: OR 0.1 p=0.03; S1613G: OR 2.7 p=0.08). CONCLUSION: Mutations in the BRCA1 gene are frequent also in our consecutive series of patients from southern Italy. An association between two detected single nucleotide polymorphisms (SNPs) and BRCA1 mutational risk was ascertained. Finally, we confirm the fact that peculiar clinical-pathological features seem to characterize patients with a family history of breast cancer and BRCA1 alterations.

BRCA1 Protein↗
PubMed2005

Biomarkers predictive for clinical efficacy of taxol-based chemotherapy in advanced breast cancer.

BACKGROUND: Several studies looked for tumor biomarkers predictive for paclitaxel sensitivity but till now no reliable biomarkers are available. The aim of this study was to verify the potential predictive value of beta-tubulin III and IV, vascular endothelial growth factor-receptor (VEGFR-1), HER2/neu and microvessel density (mVD), in a group of 70 patients with advanced breast cancer (ABC) treated with paclitaxel-based chemotherapy. PATIENTS AND METHODS: Immunohistochemical analysis (ICA) of HER2, VEGFR-1, mVd, beta-tubulin III and beta-tubulin IV expression were performed in a series of 72 advanced breast cancer. Furthermore apoptotic fraction with TUNEL analysis was evaluated. RESULTS: beta-tubulin III ICA expression was predictive of progression after chemotherapy. In fact only 2% of the patients with low beta-tubulin III expression progressed after paclitaxel chemotherapy vs 38% of those with high beta-tubulin III tumor expression (P=0.000; by chi(2)). This evidence was confirmed by a logistic regression analysis (OR 28.789; 95% CI 3.212-258,072; P=0.004). There was not a significant association between other biomarkers' characteristics and clinical response to chemotherapy. A Cox multivariate analysis, with overall survival as a dependent variable, showed that only HER2 expression was independently associated (OR 2.39; 95% CI 1.09-5.23; P=0.03) with overall survival. CONCLUSIONS: We suggest that class III beta-tubulin immunohistochemical expression analysis could be a potentially relevant tumor biomarker for paclitaxel resistance in advanced breast cancer patients.

Adult↗
PubMed2004

Genetic alterations in hereditary breast cancer.

Genetic linkage studies have led to the identification of highly penetrant genes as the possible cause of inherited cancer risk in many cancer-prone families. Most women with a family history of breast/ovarian cancer have tumors characterized by alterations in particular genes, mainly BRCA1 and BRCA2, but also CHK2, ATM, STK11 and others. This paper examines the BRCA1 and BRCA2 genes, focusing on the Italian pattern of mutations. The function of these two genes, classified as tumor suppressors, is linked with key metabolic mechanisms such as DNA damage repair, regulation of gene expression and cell cycle control. The pathological BRCA allelic variants may cause alteration of protein function, transcriptional activity and DNA repair; accumulation of the defects leads to widespread chromosome instability that may be directly responsible for cancer formation. In fact, mutations in BRCA1 and BRCA2, conferring a highly increased susceptibility to breast and ovarian cancer, do not lead to cancer by themselves. The current consensus is that these are 'caretaker' genes, which, when inactivated, allow other genetic defects to accumulate. The nature of these other molecular events may define the pathway through which BRCA1 and BRCA2 act. The BRCA mutation spectrum is complex, and the significance of most nucleotide alterations is difficult to understand. Moreover, the mutation pattern seems to be related to ethnicity. The Italian Consortium of Hereditary Breast and Ovarian Cancer has reviewed 1758 families; 23% have been found to be carriers of pathogenetic mutations in BRCA1 or BRCA2. Founder mutations have been described in geographically restricted areas of Italy; a regional founder effect has been demonstrated in Italy for the mutations BRCA1 5083del19 and BRCA2 8765delAG, and a probable new founder mutation has been characterized in Tuscany. The presence of founder mutations has practical implications for genetic testing.

Adult↗
PubMed2004

Awareness of breast cancer genetics and interest in predictive genetic testing: a survey of a southern Italian population.

BACKGROUND: Before starting a molecular screening program for breast cancer risk and in order to develop ad hoc educational strategies, a population survey in Apulia, Italy, was performed to gather information on women's awareness of breast cancer genetics and their attitude toward genetic testing for breast cancer risk. PATIENTS AND METHODS: A consecutive series of 677 healthy women with or without a family history of breast cancer, who attended the outpatient clinics of Lega Italiana per la Lotta contro i Tumori in Bari, Italy, for preventive visits, were asked to complete a 20-item questionnaire on socio-demographics, risk perception, psychological characteristics and interest in genetic testing for breast cancer predisposing genes. RESULTS: Most women (77%) reported knowing something about the genetics of breast cancer; only 7% of the women were not interested at all in genetic testing. These figures were not significantly different for women with or without a family history of breast cancer. The two most frequently cited reasons for being interested in genetic testing, accounting for more than 50% of collected responses, were 'to learn about your children's risk' and 'to help advance research'. On multiple logistic regression analysis, only older age [odds ratio (OR) 1.9; 95% confidence interval (CI) 1.3-2.9] was associated with women's knowledge of genetic testing. Moreover, marital status (OR 4.0; 95% CI 1.1-14.6) and thinking of cancer (OR 2.2; 95% CI 1.0-4.7) independently predicted the interest in having genetic testing. CONCLUSIONS: Southern Italian women seem highly interested in genetic testing for breast cancer risk. However, their expectations mainly regard their concerns about their children or their altruistic need to help research rather than the idea of a direct clinical benefit. The great interest of the women in genetic testing probably reflects their inappropriate knowledge of the information that genetic testing can provide for breast cancer risk analysis.

Adult↗
PubMed2004

Antibodies to inner ear antigens in Meniere's disease.

Meniere's disease (MD) is an idiopathic inner ear disorder characterized by fluctuating hearing loss, episodic vertigo and tinnitus. Its aetiology is unknown, although there is growing evidence that autoimmunity may be involved in its development. Using the Western blot immunoassay, we examined the reactivity to bovine inner ear antigens of sera from a series of MD patients who had previously been extensively studied for the presence of antibodies to collagens and membrane proteins. Reactivity to inner ear antigens of molecular weight 44 and 53 kD was found in 11/25 (44%) and 10/25 (40%) of the patients, respectively; both antigens were absent in the sera of healthy donors. It is still unclear whether the antibodies to 44 and 53 kD proteins play a role in the pathogenesis of MD or if they instead represent the result of inflammation and tissue destruction. Even if the latter is true, they may contribute to the perpetuation of the disease or play a role as a cofactor in association with other mechanisms.

Adult↗
PubMed2003

Epigenetic inactivation of the Ras-association domain family 1 (RASSF1A) gene and its function in human carcinogenesis.

The Ras GTPases are a superfamily of molecular switches that regulate cellular proliferation and apoptosis in response to extra-cellular signals. The regulation of these pathways depends on the interaction of the GTPases with specific effectors. Recently, we have cloned and characterized a novel gene encoding a putative Ras effector: the Ras-association domain family 1 (RASSF1) gene. The RASSF1 gene is located in the chromosomal segment of 3p21.3. The high allelic loss in a variety of cancers suggested a crucial role of this region in tumorigenesis. At least two forms of RASSF1 are present in normal human cells. The RASSF1A isoform is highly epigenetically inactivated in lung, breast, ovarian, kidney, prostate, thyroid and several other carcinomas. Re-expression of RASSF1A reduced the growth of human cancer cells supporting a role for RASSF1 as a tumor suppressor gene. RASSF1A inactivation and K-ras activation are mutually exclusive events in the development of certain carcinomas. This observation could further pinpoint the function of RASSF1A as a negative effector of Ras in a pro-apoptotic signaling pathway. In malignant mesothelioma and gastric cancer RASSF1A methylation is associated with virus infection of SV40 and EBV, respectively, and suggests a causal relationship between viral infection and progressive RASSF1A methylation in carcinogenesis. Furthermore, a significant correlation between RASSF1A methylation and impaired lung cancer patient survival was reported, and RASSF1A silencing was correlated with several parameters of poor prognosis and advanced tumor stage (e.g. poor differentiation, aggressiveness, and invasion). Thus, RASSF1A methylation could serve as a useful marker for the prognosis of cancer patients and could become important in early detection of cancer.

Animals↗
PubMed2001

Mutations spanning P53 exons 5-9 detected by non-isotopic RNAse cleavage assay and protein expression in human colon cancer.

The non-isotopic assay (NIRCA), based on the observation that RNAse is able to specifically cleave a single mismatch in RNA/RNA duplexes, has been recently proposed to detect p53 mutations. To verify the use of this method as a valid screening for P53 mutations in a routinely collected cancer series, we used this assay on 3 cases with normal and 5 cases with abnormal P53 expression detected by Western blots. In all cases, P53 exons 5-6, 7 and 8-9 regions were analyzed. There were mutations only in the five overexpressed cases: two cases showed mutations in exon 5, one between intron 6 and exon 6 and two in the region spanning exons 8 and 9. Our experience showed NIRCA to be fast, reliable and providing the ability to study long target regions in a single step, thus making this assay useful for genetic screenings.

Colonic Neoplasms↗
PubMed2000

Cell cycle-independent removal of UV-induced pyrimidine dimers from the promoter and the transcription initiation domain of the human CDC2 gene.

To assess whether removal of UV-induced cyclobutane pyrimidine dimers (CPDs) occurs with equal efficiency at different stages of the cell cycle in a cell cycle-regulated gene, we have analyzed repair of CPDs, following a single dose of UV, in normal human fibroblasts that were synchronized in either G(0) or S phase. Based on a single nucleotide resolution analysis, we established a detailed map of DNA repair rates along the promoter region and the transcription initiation area of the human CDC2 gene. The promoter of this gene is covered by an array of sequence-specific transcription factors located between nt -280 and -9 relative to the major transcription start site. In both quiescent and S phase-synchronized fibroblasts the majority of these sequences were poorly repaired even after 24 h, probably as a result of the constitutive binding of transcription factors throughout the cell cycle. A domain of fast repair was found at sequences surrounding the transcription initiation site and continuing downstream for approximately 80 nt. CPD removal from this domain was preferential in both quiescent and proliferating fibroblasts, despite lower levels of global genome repair and a lack of CDC2 transcription in quiescent cells. We suggest that sequences involved in transcription initiation may be book-marked for efficient repair throughout the cell cycle, even when the gene is temporarily not expressed.

Base Sequence↗
PubMed2000

Prognostic value of left ventricular hypertrophy and geometry in patients with a first, uncomplicated myocardial infarction.

BACKGROUND: The prognostic impact of left ventricular (LV) geometry on cardiovascular risk for patients with a first, uncomplicated acute myocardial infarction (AMI), and echocardiographic ejection fraction > or =50% has not been well described. METHODS AND RESULTS: Accordingly, 111 AMI consecutive patients (mean age 59.3+/-10 years) performed echocardiographic examination at predischarge. LV mass was calculated by means of Devereux's formula and subsequently indexed by body surface area. Fifty-three patients had LV hypertrophy and 58 patients had normal LV mass. The two groups were homogeneous for demographic, clinical and angiographic variables as well as for the incidence of residual ischemia on predischarge stress testing. During follow-up period there were 24 cardiac events (cardiac death, unstable angina and non-fatal reinfarction) in the 53 patients with LV hypertrophy and only four events in the remaining 58 patients without LV hypertrophy (RR=2.45; CI=1.76-3.41; P<0.0001). The patients with concentric LV hypertrophy showed a higher incidence of events (64%) than patients with eccentric LV hypertrophy (32%, P<0. 05) and patients with normal geometry and mass (6%, P<0.0001). Multivariate Cox regression model identified concentric geometry as the most powerful predictor of combined end-points (chi(2)=32.7, P<0. 0001). CONCLUSIONS: An increased LV mass and concentric geometry resulted important independent markers of an adverse outcome in patients with a first, uncomplicated myocardial infarction and good LV function.

Aged↗
PubMed2000

Usefulness of the severity and extent of wall motion abnormalities as prognostic markers of an adverse outcome after a first myocardial infarction treated with thrombolytic therapy.

The prognostic value of wall motion score index (WMSI), assessed at predischarge after a first acute myocardial infarction (AMI) in the thrombolytic era, is still not well known. One-hundred forty-four consecutive patients with a first AMI treated with thrombolytic therapy underwent exercise testing and echocardiography at rest before discharge and were followed-up for a mean period of 18 months. During follow-up, there were 32 cardiac events (12 patients had cardiac deaths, 8 had unstable angina pectoris, 1 had nonfatal reinfarction, and 11 patients had congestive heart failure). The patients who experienced any cardiac event had a higher WMSI (1.67+/-0.15 vs. 1.30+/-0.16, p<0.0001), a higher end-systolic volume (75.1+/-34 vs. 59.5+/-22 ml, p<0.01), and a lower ejection fraction (47+/-16% vs. 55+/-10%, p<0.001) at predischarge than patients without events. The incidence of a positive predischarge exercise testing did not differ between patients with and without cardiac events (22% vs. 24%, p = NS). Multivariate Cox regression analysis, including clinical, exercise results, and echocardiographic parameters, showed that the most powerful predictor of a subsequent event was a resting WMSI > or =1.50 before discharge (chi-square 17.8, p<0.0001). Thus, in patients with a first AMI who underwent thrombolysis, the severity and extent of echocardiographically detected wall motion abnormalities are important independent predictors of cardiac events.

Aged↗
PubMed2000

Low-dose dipyridamole infusion acutely increases exercise capacity in angina pectoris: a double-blind, placebo controlled crossover stress echocardiographic study.

OBJECTIVES: The aim of this study was to assess whether endogenous accumulation of adenosine, induced by low-dose dipyridamole infusion, protects from exercise-induced ischemia. BACKGROUND: Adenosine is a recognized mediator of ischemic preconditioning in experimental settings. METHODS: Ten patients (all men: mean age 63.4 +/- 7.3 years) with chronic stable angina, angiographically assessed coronary artery disease (n = 7) or previous myocardial infarction (n = 3) and exercise-induced ischemia underwent on different days two exercise-stress echo tests after premedication with placebo or dipyridamole (15 mg in 30 min, stopped 5 min before testing) in a double-blind, placebo controlled, randomized crossover design. RESULTS: In comparison with placebo, dipyridamole less frequently induced chest pain (20% vs. 100%, p = 0.001) and >0.1 mV ST segment depression (50% vs. 100%, p < 0.05). Wall motion abnormalities during exercise-stress test were less frequent (placebo = 100% vs. dipyridamole = 70%, p = ns) and significantly less severe (wall motion score index at peak stress: placebo = 1.55 +/- 0.17 vs. dipyridamole = 1.27 +/- 0.2, p < 0.01) following dipyridamole, which also determined an increase in exercise time up to echocardiographic positivity (placebo = 385.9 +/- 51.4 vs. dipyridamole = 594.4 +/- 156.9 s, p < 0.01). CONCLUSIONS: Low-dose dipyridamole infusion increases exercise tolerance in chronic stable angina, possibly by endogenous adenosine accumulation acting on high affinity A1 myocardial receptors involved in preconditioning or positively modulating coronary flow through collaterals.

Adenosine↗
PubMed2000

TGF-beta1 and IGF-1 expression are differently regulated by serum in metastatic and non-metastatic human breast cancer cells.

Transforming growth factor-beta (TGF-beta) exerts an inhibitory effect on epithelial cell proliferation while insulin-like growth factor-1 (IGF-1) is a positive regulator of proliferation and together they may participate in driving neoplastic progression. The regulation of TGF-beta1 and IGF-1 gene expression was analyzed in an in vitro model of an estrogen receptor positive (ER+), non-metastatic (MCF-7) and an (ER-), metastatic (MDA-MB-435) breast cancer cell line, respectively. Our results indicate a loss of the regulation of TGF-beta1 and the gain of the expression and upregulation of IGF-1 pathways during malignant progression. These data demonstrate that two factors, convergent on cell growth, can have divergent roles in the regulation of the expression of TGF-beta1.

Blood↗
PubMed1999

In vivo structure of two divergent promoters at the human PCNA locus. Synthesis of antisense RNA and S phase-dependent binding of E2F complexes in intron 1.

Proliferating cell nuclear antigen (PCNA) synthesis is strictly regulated during the cell cycle. To investigate PCNA transcriptional regulation, we have analyzed protein-DNA interactions at the promoter region and in the first intron in quiescent fibroblasts and following serum stimulation. Twenty putative protein-binding sites, distributed in two divergent promoters at the PCNA locus, were identified in vivo by genomic footprinting. These elements bind transcription factors continuously throughout the cell cycle with the exception of one E2F consensus site, located in the first intron at position +583. This E2F site becomes strongly occupied 18 h after serum stimulation, implying that an E2F activator complex plays a role in activation of the PCNA gene at the onset of S phase. We detected a 500-600-base pair-long antisense transcript by Northern blot analysis. This RNA has no apparent coding capacity and is constitutively transcribed from a promoter located within the first intron. We suggest that silencing of the PCNA gene is accomplished through base pairing between sense pre-mRNA and antisense RNA. The binding of S phase-specific E2F complexes at the +583 element may help to overcome the negative effect of the antisense transcript, which results in up-regulation of PCNA expression in proliferating cells.

Base Pairing↗
PubMed1999

C-reactive protein as a marker for cardiac ischemic events in the year after a first, uncomplicated myocardial infarction.

The prognostic role of C-reactive protein levels in patients with a first acute myocardial infarction, an uncomplicated in-hospital course, and the absence of residual ischemia on a predischarge ergometer test and with an echocardiographic ejection fraction > or = 50% has not been described. C-reactive protein was determined during hospitalization in 64 patients (55 men, mean age 64.6 +/- 10.4 years). The patients were followed up for 13 +/- 4 months and the following cardiac events were recorded: cardiac death, new-onset angina pectoris, and recurrent myocardial infarction. Patients who developed cardiac events during the follow-up period had significantly higher C-reactive protein values than patients without events (3.61 +/- 2.83 vs 1.48 +/- 2.07 mg/dl, p <0.001). The probability of cumulative end points was: 6%, 12%, 31%, and 56% (p = 0.006; RR 3.55; confidence interval 1.56 to 8.04), respectively, in patients stratified by quartiles of C-reactive protein (< 0.45, 0.45 to 0.93, 0.93 to 2.55 and > 2.55 mg/dl). In the Cox regression model, only increased C-reactive protein levels were independently related to the incidence of subsequent cardiac events (chi-square 9.8, p = 0.001). Thus, increased C-reactive protein levels are associated with a worse outcome among patients with a first acute myocardial infarction, an uncomplicated in-hospital course without residual ischemia on the ergometer test, and with normal left ventricular function.

Aged↗
PubMed1997

Constitutive protection of E2F recognition sequences in the human thymidine kinase promoter during cell cycle progression.

The sequences responsible for S phase-specific induction of the human thymidine kinase (TK) gene have been mapped to a small region that contains putative E2F binding sites. We have analyzed protein-DNA interactions at the TK promoter during cell cycle progression in human fibroblasts using an in vivo footprinting approach. We found 14 protein binding sites that were occupied in vivo. All of the sites (among them two inverted CCAAT boxes and several Sp1 sites) bound transcription factors constitutively throughout the cell cycle, i.e. none of the factor binding was cell cycle-dependent. An E2F-like site located between nucleotides -97 and -89 relative to the major transcription start site was protected in G0, G1, S, and G2 phases. This cell cycle-independent protection of E2F sequences in the TK promoter differs from the G0/G1-restricted binding of E2F complexes observed for genes in which the E2F sites function as repressor elements (Tommasi, S., and Pfeifer, G. P. (1995) Mol. Cell. Biol. 15, 6901-6913; Zwicker, J., Liu, N., Engeland, K., Lucibello, F. C., and Müller, R. (1996) Science 271, 1595-1597). A comparison of several genes containing E2F motifs indicates that E2F sites located in proximity to the transcription initiation site (-50 to +20) in TATA-less promoters predominantly function as repressor elements, while in other genes constitutively bound E2F complexes located further upstream mediate activation presumably in conjunction with a functional TATA box.

Base Sequence↗
PubMed1997

Sunlight induces pyrimidine dimers preferentially at 5-methylcytosine bases.

The most prevalent DNA lesion induced by UV irradiation is the cyclobutane pyrimidine dimer (CPD), which forms at positions of neighboring pyrimidines. Here we show that the rare DNA base 5-methylcytosine is the preferred target for CPD formation when cells are irradiated with natural sunlight. We have mapped the distribution of CPDs formed in normal human keratinocytes along exons of the p53 gene. Codons 196, 245, 248, and 282, which are mutational hot spots in skin cancers, are only weakly to moderately susceptible to formation of CPDs after irradiation with UVC (254 nm) or UVB (320 nm) light sources. However, when cells were exposed to natural sunlight, CPD formation was enhanced up to 15-fold at these codons due to the presence of 5-methylcytosine bases. These results suggest that CPDs containing 5-methylcytosine may play an important role in formation of sunlight-induced skin tumors and that methylation of CpG sequences, besides being involved in spontaneous mutagenesis processes, can also create preferential targets for environmental mutagens and carcinogens.

5-Methylcytosine↗
PubMed1996

Inhibition of transcription factor binding by ultraviolet-induced pyrimidine dimers.

The formation of DNA photoproducts by ultraviolet (UV) light is responsible for the induction of mutations and the development of skin cancer. Cis-syn cyclobutane pyrimidine dimers (pyrimidine dimers) are the most frequent lesions produced in DNA by UV irradiation. Besides being mutagenic, pyrimidine dimers may interfere with other important DNA-dependent processes. To analyze the effects of pyrimidine dimers on the ability of DNA sequences to be recognized by trans-acting factors, we have incorporated site-specific T-T dimers into oligonucleotides containing the recognition sequences of the sequence-specific transcription factors E2F, NF-Y, AP-1, NF kappa B, and p53. In each case, presence of the photodimer strongly inhibited binding of the respective transcription factor complex. Reduction of binding varied between 11- and 60-fold. The results indicate that the most common UV-induced DNA lesion can interfere severely with binding of several important cell cycle regulatory and DNA damage responsive transcription factors. We suggest that inhibition of transcription factor binding may be a major biological effect of UV radiation since promoter regions are known to be repaired inefficiently and since UV damage can deregulate the function of a large number of different factors.

Binding Sites↗