Biomedical subjects

M Caputi

Publications and source records attributed to M Caputi.

At least 19 recordsLinked to original sources

PubMed2006

Cell cycle control and beyond: emerging roles for the retinoblastoma gene family.

Rb family proteins (pRb/p105, Rb2/p130 and p107) play a key role in cell cycle control and are worthily involved in transcription repression and tumor suppression. The mechanisms of transcriptional activation and repression by the Rb gene family has been extensively investigated: pRb, pRb2/p130 and p107 interact with different E2F family factors and can inhibit E2F responsive promoters, interfering with progression of cell cycle, gene transcription, initiation of apoptotic process and cell differentiation. Recent studies have indicated that Rb and Rb2/p130 may be involved in cellular response to DNA damage events, by influencing the transcription of factors involved in DNA repair pathways. In particular, evidences suggest that Rb loss and target gene deregulation impacts on the repair of UV-induced pyrimidine pyrimidone photoproducts (6-4 PP) by regulating the expression of several DNA damage factors involved in UV DNA damage repair processes, including proliferating cell nuclear antigen. Ongoing studies are focused on the mechanisms by which Rb family genes drive cell cycle exit following DNA damage induction, and how Rb gene family's interaction with chromatin remodeling factors can influence DNA repair dynamics.

Animals↗

PubMed2005

Cell cycle related proteins as prognostic parameters in radically resected non-small cell lung cancer.

BACKGROUND: Experimental evidence suggests that lung cancer development and progression can be linked to an increased proliferation rate. AIMS/METHODS: To evaluate the immunohistochemical expression of seven components of the cell cycle machinery in a series of well characterised non-small cell lung cancer (NSCLC) specimens (n = 105). RESULTS: Multivariate analysis revealed that simultaneous loss of expression of three of these factors--cyclin D1, the cyclin dependent kinase inhibitor p16, and the tumour suppressor retinoblastoma protein Rb2/p130--correlated with survival, confirming the hypothesis that the cyclin D1-p16-retinoblastoma tumour suppressor pathway is inactivated in most lung cancer samples. CONCLUSIONS: These results suggest that loss of control of cell cycle checkpoints is a common occurrence in lung cancer and support the idea that functional cooperation between different cell cycle regulatory proteins constitutes another level of regulation in cell growth control and tumour suppression.

Aged↗

PubMed2005

Mediastinal images resembling thymus following 131-I treatment for thyroid cancer.

The follow-up of Differentiated Thyroid Cancer conventionally includes serum thyroglobulin and periodic Whole Body Scans. The uptake of 131-I in normal and pathological tissues different from metastatic thyroid cancer sites is a cause of false-positive scans. Among them, mediastinal uptake caused by thymic hyperplasia can be observed. The aim of the present study was to review a series of 573 patients with differentiated thyroid cancer treated with 131-I after surgery between 1992 and 2003 looking above all for those with mediastinal images resembling thymus. This evaluation is presented together with some hypotheses on the relationships between thymus and thyroid. Moreover, some considerations are made on the differential diagnosis between thymus and mediastinal tumour thyroid residues.

Adenocarcinoma↗

PubMed2004

Mediastinal hibernoma: a case report.

Hibernomas are rare benign tumours that arise most often in adults from the remnants of fetal brown adipose tissue. They usually affect muscle and subcutaneous tissue and are asymptomatic and slow growing. The distribution of this tumour follows the sites of persistence of brown fat. Out of more then 100 cases described in the word literature only three hybernomas were mediastinal. A recent clinicopathological study of 170 cases from the Armed Forces Institute of Pathology confirmed the exceptionality of the intrathoracic location. This report describes a very rare case of mediastinal hibernoma in a young man.

Adult↗

PubMed2002

Soluble leptin receptor and insulin resistance as determinant of sleep apnea.

OBJECTIVE: To investigate the possible associations between sleep apnea syndrome, hyperinsulinemia/insulin resistance and hyperleptinemia in subjects with different degrees of body mass index. DESIGN: To test for the presence or absence of sleep apnea syndrome in association with hyperinsulinemia/insulin resistance and hyperleptinemia. SUBJECTS: Twenty subjects with different body mass index (mean BMI 30.9+/-4.2). MEASUREMENTS: Insulin action and plasma soluble leptin receptor were measured by euglycemic hyperinsulinemic glucose clamp and by ELISA method, respectively. Occurrence of sleep apnea syndrome was assessed by clinical and nocturnal monitoring using a validated sleep apnea recorder. RESULTS: The apnea/hypopnea index (AHI) was positively correlated with plasma soluble leptin receptor (0.76; P<0.001) and negatively with the degree of insulin-mediated glucose uptake (r=-0.73; P<0.001). In a multivariate analysis AHI was associated with plasma soluble leptin receptor and insulin mediated glucose uptake independently of age, gender, BMI, plasma leptin levels and PaCO(2). CONCLUSION: Sleep apnea syndrome is associated with plasma soluble leptin receptor and insulin resistance independently of BMI.

Adult↗

PubMed2001

Urokinase-type plasminogen activator up-regulates the expression of its cellular receptor through a post-transcriptional mechanism.

We have recently reported that the urokinase-type plasminogen activator (uPA) up-regulates the cell surface expression of its own receptor (uPAR) in several cell types, independently of its enzymatic activity. uPA has no effect on kidney 293 cells which do not express uPAR and then cannot bind uPA. Kidney cells, transfected with the coding region of uPAR cDNA, express very large amounts of uPAR and respond to uPA stimulation by regulating uPAR both at mRNA and protein levels. uPA effect occurs also in the presence of the transcriptional inhibitor dichloro-ribobenzimidazole, whereas it is abolished by the protein synthesis inhibitor cycloheximide. Moreover, uPA-dependent uPAR up-regulation correlates with the increase of a complex between the coding region of uPAR mRNA and an unknown cellular factor. We then propose that uPA regulates uPAR expression at a post-transcriptional level, by promoting the binding of uPAR mRNA to a stabilizing factor.

3' Untranslated Regions↗

PubMed2001

Determination of the RNA binding specificity of the heterogeneous nuclear ribonucleoprotein (hnRNP) H/H'/F/2H9 family.

Members of the heterogeneous nuclear ribonucleoprotein (hnRNP) H protein family, H, H', F, and 2H9, are involved in pre-mRNA processing. We analyzed the assembly of these proteins from splicing extracts onto four RNA regulatory elements as follows: a high affinity hnRNP A1-binding site (WA1), a sequence involved in Rev-dependent export (p17gag INS), an exonic splicing silencer from the beta-tropomyosin gene, and an intronic splicing regulator (downstream control sequence (DCS) from the c-src gene. The entire family binds the WA1, instability (INS), and beta-tropomyosin substrates, and the core-binding site for each is a run of three G residues followed by an A. Transfer of small regions containing this sequence to a substrate lacking hnRNP H binding activity is sufficient to promote binding of all family members. The c-src DCS has been shown to assemble hnRNP H, not hnRNP F, from HeLa cell extracts, and we show that hnRNP 2H9 does not bind this element. The DCS contains five G residues followed by a C. Mutation of the C to an A changes the specificity of the DCS from a substrate that binds only hnRNP H/H' to a binding site for all hnRNP H family members. We conclude that the sequence GGGA is recognized by all hnRNP H family proteins.

Animals↗

PubMed2001

RB2/p130 gene-enhanced expression down-regulates vascular endothelial growth factor expression and inhibits angiogenesis in vivo.

Angiogenesis is an essential step in the progression of tumor formation and development. The switch to an angiogenetic phenotype can occur as a distinct step before progression to a neoplastic phenotype and is linked to genetic changes such as mutations in key cell cycle regulatory genes. The pathogenesis of the angiogenetic phenotype may involve the inactivation of tumor suppressor genes such as the "guardian of the genome," p53, and the cyclin-dependent kinase inhibitor p16. Retinoblastoma family member RB2/p130 encodes a cell cycle regulatory protein and has been found mutated in different tumor types. Overexpression of RB2/p130 not only suppresses tumor formation in nude mice but also causes regression of established tumor grafts, suggesting that RB2/p130 may modulate the angiogenetic balance. We found that induction of RB2/p130 expression using a tetracycline-regulated gene expression system as well as retroviral and adenoviral-mediated gene delivery inhibited angiogenesis in vivo. This correlated with pRb2/p130-mediated down-regulation of vascular endothelial growth factor protein expression both in vitro and in vivo.

Animals↗

PubMed2000

Inducible pRb2/p130 expression and growth-suppressive mechanisms: evidence of a pRb2/p130, p27Kip1, and cyclin E negative feedback regulatory loop.

The retinoblastoma family of proteins, pRb/p105, p107, and pRb2/ p130, cooperate to regulate cell cycle progression through the G1 phase of the cell cycle. Each of the family members realize their common goal of G1-S checkpoint regulation through overlapping and unique growth regulatory pathways. We took advantage of a tetracycline-regulated gene expression system to control the expression of RB2/p130 in JC virus-induced hamster brain tumor cells to study in vivo the molecular mechanisms used by pRb2/p130 to elicit its growth-suppressive function. We have previously used this system to demonstrate that induction of pRb/ p130 expression suppresses tumor growth in vivo by overcoming neoplastic transformation mediated by the large T-antigen oncoprotein of JCV (JCV TAg). Here we found that induction of pRb2/p130 in vivo specifically inhibits cyclin A- and cyclin E-associated kinase activity and by doing so induces p27Kip1 levels presumably by inhibiting p27Kip1-targeted proteolysis by cyclin E-Cdk2 phosphorylation of p27Kip1. RB2/p130 induction also decreased cyclin A and the transcription factor E2F-1 while increasing cyclin E at both the transcriptional and protein levels of expression. The growth inhibitory activity of pRb2/p130 also correlated with its E2F-binding capacity. Furthermore, p27Kip1 and pRb2/p130 were found to be targets of the JCV TAg oncoprotein and to interact in vivo with each other independently from the presence of TAg. Interestingly, pRb2/p130 expression negatively modulated the binding of p27Kip1 to JCV TAg. These data suggest that pRb2/p130 and p27Kip1 may cooperate in regulating cellular proliferation, and both may be involved in a negative feedback regulatory loop with cyclin E.

Animals↗

PubMed2000

Mutations in the retinoblastoma-related gene RB2/p130 in lung tumors and suppression of tumor growth in vivo by retrovirus-mediated gene transfer.

The retinoblastoma (Rb) family consists of the tumor suppressor pRb/p105 and related proteins p107 and pRb2/p130. Recent immunohistochemical studies of the retinoblastoma family of proteins in 235 specimens of lung cancer show the tightest inverse association between the histological grading in the most aggressive tumor types and pRb2/p130. This led us to study a panel of human lung cancers for mutations in the RB2/p130 gene. Mutations in the Rb-related gene RB2/p130 were detected in 11 of 14 (78.5%) primary lung tumors by single-strand conformation polymorphism and sequence analysis. A Moloney leukemia virus-based retroviral system was set up, and a comparable viral concentration of 1 x 10(7) infectious units/ml was obtained. Retrovirus-mediated delivery of wild-type RB2/p130 to the lung tumor cell line H23 potently inhibited tumorigenesis in vitro and in vivo, as shown by the dramatic growth arrest observed in a colony assay and the suppression of anchorage-independent growth potential and tumor formation in nude mice. The tumors transduced with the RB2/p130 retrovirus diminished in size after a single injection, and a 12-fold reduction in tumor growth after RB2/p130 transduction compared with the Pac-transduced tumors (92% reduction, P = 0.003) and lacZ-transduced tumors (93% reduction, P < 0.001) was found to be statistically significant. These findings provide the missing confirmation that RB2/p130 is a "bona fide" tumor suppressor gene and strengthen the hypothesis that it may be a candidate for cancer gene therapy for lung cancer.

Adenocarcinoma↗

PubMed2000

Mutations in the retinoblastoma-related gene RB2/p130 in primary nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an endemic cancer in southern China and northern Africa, and its pathogenesis is not yet well defined at the molecular level. Although the involvement of p53 and of the retinoblastoma gene (RB/p105) in NPC has been well studied, there is paucity of mutational data regarding the retinoblastoma-related gene RB2/p130 in primary tumors and particularly in NPC. We have shown previously that RB2/p130 could be rearranged in a nasopharyngeal cell line. In the present study, we screened by single-strand conformation polymorphism and sequence analysis the retinoblastoma-related gene RB2/p130 for mutations within exons 19-22. Mutations in the RB2/p130 gene were detected in 3 of 10 primary human NPCs from Northern Africa (30%). These findings, along with previous data showing that genetic replacement of RB2/p130 restores a normal growth pathway in the nasopharyngeal cell line Hone-1, strengthen the hypothesis that genetic changes of RB2/p130 may be involved in the development and/or progression of nasopharyngeal cancer and suggest that RB2/p130 could be considered a tumor suppressor gene and may be a candidate for novel gene therapeutic approaches for NPC.

DNA Mutational Analysis↗

PubMed2000

The RB2/p130 gene: the latest weapon in the war against lung cancer?

Lung cancer is the second cause of death after cardiovascular diseases and is the major cause of cancer deaths in the Western world. Large scale screening trials conducted 15-20 years ago using chest X-rays and sputum cytology were able to detect stage I cancers but failed to impact on survival. This is because of the early metastatic potential of small primary tumors. It is important then to detect lung cancer at an earlier stage, studying and identifying genetic lesions that could indicate a new target(s) for gene therapy. The retinoblastoma-related gene pRb2/p130, a new tumor suppressor gene cloned in 1993, is emerging as one of the candidate markers and targets for gene therapeutic approach. Effective genetic therapy requires both a genetic material to be used therapeutically and a means to deliver it. A scope for this review is to examine some of the gene delivery systems mostly used, discussing their weaknesses and strengths, and to discuss the role of pRb2/p130 in lung cancer.

Gene Transfer Techniques↗

PubMed1999

hnRNP A/B proteins are required for inhibition of HIV-1 pre-mRNA splicing.

Splicing of the human immunodeficiency virus type 1 (HIV-1) pre-mRNA must be inefficient to provide a pool of unspliced messages which encode viral proteins and serve as genomes for new virions. Negative cis-regulatory elements (exonic splicing silencers or ESSs) are necessary for HIV-1 splicing inhibition. We demonstrate that heterogeneous nuclear ribonucleoproteins (hnRNPs) of the A and B group are trans-acting factors required for the function of the tat exon 2 ESS. Depletion of hnRNP A/B proteins from HeLa cell nuclear extract activates splicing of tat exon 2 pre-mRNA substrate. Splicing inhibition is restored by addition of recombinant hnRNP A/B proteins to the depleted extract. A high-affinity hnRNP A1-binding sequence can substitute functionally for the ESS in tat exon 2. These results demonstrate that hnRNP A/B proteins are required for repression of HIV-1 splicing.

Base Sequence↗

PubMed1999

Independent prognostic role of p16 expression in lung cancer.

OBJECTIVES: The cyclin-dependent kinase p16 (also known as Ink4A, Mts1, Cdkn2, and Cdkn4i) has been proposed as a tumor suppressor gene mapped on chromosome segment 9p21. This study evaluated p16 protein expression in 135 lung cancer specimens and investigated potential genetic alterations occurring in this gene. RESULTS: We found altered p16 immunohistochemical expression to be a frequent event in lung cancer and to be independent of either the histologic type or any other clinical-pathologic feature. Western blot analyses performed on about one third of the specimens correlated highly with these results. In addition, we found p16 immunohistochemical expression to be a favorable prognostic factor in lung cancer in that its reduction or loss correlated with a worse outcome for the patients. Polymerase chain reaction amplification and direct sequencing of p16 exons 1 and 2 revealed no mutations, indicating that p16-altered expression in lung cancer is not necessarily linked to mutational events of these genes. CONCLUSIONS: We conclude that p16-altered expression is both an independent and frequent event in lung cancer and may have an important role in tumorigenesis and in malignant progression of a significant proportion of these cancers. However, the actual incidence and relevance of p16 mutations in this neoplasm continues to be debated, and its analysis seems inconclusive. Our results suggest a prognostic role for the immunodetection of this protein on formalin-fixed and paraffin-embedded specimens. They further suggest its routine use in the evaluation of the frequently unpredictable behavior of lung cancer.

Adenocarcinoma↗

PubMed1999

Regulation of fibronectin EDA exon alternative splicing: possible role of RNA secondary structure for enhancer display.

The fibronectin primary transcript undergoes alternative splicing in three noncoordinated sites: the cassette-type EDA and EDB exons and the more complex IIICS region. We have shown previously that an 81-nucleotide region within the EDA exon is necessary for exon recognition and that this region contains at least two splicing-regulatory elements: a polypurinic enhancer (exonic splicing enhancer [ESE]) and a nearby silencer element (exonic splicing silencer [ESS]). Here, we have analyzed the function of both elements in different cell types. We have mapped the ESS to the nucleotide level, showing that a single base change is sufficient to abolish its function. Testing of the ESE and ESS elements in heterologous exons, individually or as part of the complete EDA regulatory region, showed that only the ESE element is active in different contexts. Functional studies coupled to secondary-structure enzymatic analysis of the EDA exon sequence variants suggest that the role of the ESS element may be exclusively to ensure the proper RNA conformation and raise the possibility that the display of the ESE element in a loop position may represent a significant feature of the exon splicing-regulatory region.

Alternative Splicing↗

PubMed1999

Prognostic role of cyclin D1 in lung cancer. Relationship to proliferating cell nuclear antigen.

We developed an immunohistochemical assay specific for cyclin D1 and suitable for formalin-fixed and paraffin-embedded sections, to evaluate cyclin D1 expression in a group of 135 surgically resected lung-cancer patients for the purpose of investigating the prognostic role of this protein in lung cancer. In addition, we compared cyclin D1 expression with the expression of proliferating cell nuclear antigen (PCNA), considered to be a reliable index of the proliferation rate. We found cyclin D1 expressed in more than 60% of the neoplastic cells in 26.5% of our specimens. A total of 24.5% of the specimens showed cyclin D1 expression in a percentage of cells ranging from 30 to 60%; 36.7% of the specimens expressed cyclin D1 in less than 30% of the cells; and 12.2% of the specimens expressed cyclin D1 in less than 1% of the evaluated cells. Western blot analyses confirmed the specificity of this assay by correlating statistically in a highly significant fashion with the immunohistochemical results (P = 0.0003). Furthermore, we found a direct relationship between cyclin D1 and PCNA immunodetection (P = 0.0004), which correlated cyclin D1 overexpression with a higher tumor proliferation rate. When we analyzed our data statistically, cyclin D1 expression was found to be a negative prognostic marker (P < 0.00005) whose expression correlates with a shorter patient survival time.

Adenocarcinoma↗

PubMed1998

p21waf1/cip1mda-6 expression in non-small-cell lung cancer: relationship to survival.

In order to clarify critical events during bronchial carcinogenesis, and to evaluate a possible prognostic role for p21 immunohistochemical detection, we assessed the immunohistochemical expression of p21 protein in 60 surgically resected non-small-cell lung cancers (NSCLCs) that had been investigated previously for their p53 protein status. We found that p21 protein was expressed in both normal and neoplastic tissue. In normal tissue, p21 immunoreactivity was detectable in a low percentage of well-differentiated cells. We found immunostaining for p21 in 80% of the investigated neoplasms. In 73.3% of the neoplasms, p21 was considered to be overexpressed. No relationship was found between p21 overexpression and tumor stage or tumor-nodal-metastatic (TNM) status. The histologic grading was slightly correlated with the p21 status (P = -0.51), with no significant differences noted between squamous carcinomas and adenocarcinomas. Survival percentage curves for our lung-cancer patients, based on a comparison of different p21 expression levels and constructed through a Kaplan-Meier analysis, showed significant differences in mean (P < 0.001) and overall (P < 0.001) survival time between patients of different p21 status, suggesting a favorable prognostic value of p21 immunostaining for NSCLC patients.

Adenocarcinoma↗

PubMed1998

[Correlation between functional and radiographic data, and broncho-alveolar cytology in patients with diffuse interstitial lung disease].

BACKGROUND: "Interstitial Lung Disease" is a term that includes a heterogeneous group of disorders characterized by variable degrees of parenchymal inflammation (alveolitis) and fibrosis. Alveolitis represents one of the most important aspects of ILD and its characterization by broncho-alveolar lavage (BAL) can give explanations of the different clinical features, in association with the evaluation of physiological changes and High Resolution Computed Tomography (HRCT). The aim of this study was to establish a correlation between variations in broncho-alveolar cells and anatomical-functional alterations in patients affected by ILD before and after corticoid therapy. METHODS: Thirty-one patients (14 males 17 females) were introduced in the study and were evaluated for clinical signs, functional parameters, HRCT and cyto-immunological aspects of BAL fluid. All data were acquired at the admission in the study, after 60 and 180 days. Patients had received prednisone 1 mg/kg/die for 60 days and, then, 0.25 mg/kg/die for 120 days. RESULTS: In lymphocyte alveolitis, a clinical-radiological improvement was frequently observed after therapy while in those with neutrophilic and eosinophilic components, no improvement was detected. CONCLUSIONS: In conclusion, BAL represents a useful tool in qualifying ILD which can be easily monitored by clinical, functional and radiological data. Therefore, a new method for the diagnosis and monitoring of ILD is suggested. This method has the marked advantage to reach a reliable diagnosis even in a high percentage of patients who refuse or can not undergo the biopsy assay.

Adult↗