Search PubMed⌕ Search

Biomedical subjects

A Iavarone

Publications and source records attributed to A Iavarone.

At least 19 recordsLinked to original sources
PubMed2004

Prognostic role of depression after lumbar disc surgery.

A total of 73 patients underwent microdiscectomy for lumbar disc herniation between September 2001 and May 2002 at the Department of Neurosurgery of the Second University of Naples. Preoperatively and 3 and 6 months after surgery, patients were assessed on the Zung Self-rating Depression Scale (SDS) and on a visual analogue scale (VAS) for the subjective perception of pain. At 3 and 12 months, we found that patients with lower SDS scores (n=41) had a better outcome regarding pain than patients with relevant depressive symptoms (n=32). In agreement with the literature, our results confirm the negative role of depression in outcome after lumbar disc surgery. We emphasize the consideration of psychological factors in the management of lumbar disc herniation.

Adolescent↗
PubMed2001

Id proteins at the cross-road of development and cancer.

A large body of evidence has been accumulated that demonstrates dominant effects of Id proteins on different aspects of cellular growth. Generally, constitutive expression of Id not only blocks cell differentiation but also drives proliferation. In some settings, it is sufficient to render cells immortal or induce oncogenic transformation. The participation of Id proteins in advanced human malignancy, where they are frequently deregulated, has been dramatically bolstered by the recent discovery that Id exert pivotal contributions to many of the essential alterations that collectively dictate malignant growth. Relentless proliferation associated with self-sufficiency in growth signals and insensitivity to growth inhibitory signals, sustained neoangiogenesis, tissue invasiveness and migration capabilities of tumor cells all share dependency on the unlimited availability of Id proteins. It is remarkable that many of these features recapitulate those physiologically propelled by Id proteins to support normal development. We propose that the participation of Id in multiple fundamental traits of cancer may be the basis for unprecedented therapeutic opportunities.

Animals↗
PubMed2001

Distinct mechanisms of cell cycle arrest control the decision between differentiation and senescence in human neuroblastoma cells.

Retinoic acid (RA) induces cell cycle arrest and differentiation of human neuroblastoma (NB) cells. Typically, NB cells differentiate along the neuronal lineage, but quiescent, "flat" cell types frequently have been described after treatment with differentiating agents. Two indistinguishable subclones of the cell line SK-N-SH, SK-N-SH-N (SH-N) and SK-N-SH-F (SH-F), display dramatically different responses to RA. In SH-N, RA induces neuronal differentiation, but in SH-F it transforms the small neuroblastic cells into large, flattened, epithelium-like cells. Here we analyze the mechanistic basis for the different effects of RA in the two NB subclones. First, we show that the flattened RA-treated SH-F expresses markers of cells undergoing replicative senescence. Inhibition of DNA synthesis by RA is significantly more rapid in SH-F than in SH-N. SH-F, which expresses basal amounts of p16(INK4A), responds to RA with elevation of p18(INK4C), marked down-regulation of cyclin D1, and swift inhibition of cyclin D-dependent kinases (cdks). Conversely, after addition of RA, SH-N retains cell cycling due to high expression of cyclin D1, the absence of Ink4 inhibitors, and accumulation of p21(Cip1). These changes result in sustained cdk activity. Accordingly, overexpression of p21(Cip1) but not p16(INK4A) induces neuronal differentiation of untreated NB cells. We propose that rapid inhibition of cdks by RA in NB leads to early cell cycle arrest, prevents neuronal differentiation, and results in a senescence-like state.

Cell Cycle↗
PubMed2001

Evidence that Myc isoforms transcriptionally repress caveolin-1 gene expression via an INR-dependent mechanism.

The c-Myc oncoprotein contributes to oncogenesis by activating and repressing a repertoire of genes involved in cellular proliferation, metabolism, and apoptosis. Increasing evidence suggests that the repressor function of c-Myc is critical for transformation. Therefore, identifying and characterizing Myc-repressed genes is imperative to understanding the mechanisms of Myc-induced tumorigenesis. Here, we employ NIH 3T3 cell lines harboring c-Myc-ER or N-Myc-ER to dissect the relationship between Myc activation and caveolin-1 expression. In this well-established inducible system, treatment with estrogen like molecules, such as tamoxifen, leads to activation of Myc, but in a tightly controlled fashion. Using this approach, we show that Myc activation induces the repression of caveolin-1 expression at the transcriptional level. We also provide two independent lines of evidence suggesting that caveolin-1 is a direct target of Myc: (i) the effect of Myc activation on caveolin-1 expression is independent of new protein synthesis, as revealed through the use of cycloheximide; and (ii) Myc-mediated repression of the caveolin-1 promoter is dependent on an intact INR sequence. Moreover, we show that expression of caveolin-1, via an adenoviral vector approach, can suppress cell transformation that is mediated by Myc activation. In support of these observations, treatment with an adenoviral vector harboring anti-sense caveolin-1 specifically potentiates transformation induced by Myc activation. Taken together, our results indicate that caveolin-1 is a direct target of Myc repression, and they also provide evidence for an additional mechanism by which Myc repression can elicit a malignant phenotype.

3T3 Cells↗
PubMed2000

Id2 is a retinoblastoma protein target and mediates signalling by Myc oncoproteins.

In mammalian cells, Id proteins coordinate proliferation and differentiation. Id2 is a dominant-negative antagonist of basic helix-loop-helix transcription factors and proteins of the retinoblastoma (Rb) family. Here we show that Id2-Rb double knockout embryos survive to term with minimal or no defects in neurogenesis and haematopoiesis, but they die at birth from severe reduction of muscle tissue. In neuroblastoma, an embryonal tumour derived from the neural crest, Id2 is overexpressed in cells carrying extra copies of the N-myc gene. In these cells, Id2 is in molar excess of the active form of Rb. The overexpression of Id2 results from transcriptional activation by oncoproteins of the Myc family. Cell-cycle progression induced by Myc oncoproteins requires inactivation of Rb by Id2. Thus, a dual connection links Id2 and Rb: during normal cell-cycle, Rb prohibits the action of Id2 on its natural targets, but oncogenic activation of the Myc-Id2 transcriptional pathway overrides the tumour-suppressor function of Rb.

Animals↗
PubMed2000

Transforming growth factor-beta1 recruits histone deacetylase 1 to a p130 repressor complex in transgenic mice in vivo.

Transforming growth factor (TGF)-beta1 functions as a tumor suppressor in vivo. Using transgenic mice, we show that hepatic TGF-beta1 overexpression inhibits abundance of the cyclin-dependent kinase activating tyrosine phosphatase cdc25A protein. The reduction in cdc25A protein levels was associated with increased binding of histone deacetylase 1 to p130 in the hepatic extracts. In cultured cells, HDAC1/p130 overexpression inhibited activity of the cdc25A promoter through an E2F site. TGF-beta1 treatment enhanced p130 binding to the cdc25A promoter E2F site assessed in chromatin immunoprecipitation assays. Hepatic proliferation induced by partial hepatectomy was associated with a decrease in the amount of HDAC1 bound to p130, without a significant decrease in p130 abundance, suggesting that HDAC1 binding to p130 may be regulated by proliferative stimuli. The induction of cdc25A abundance induced by partial hepatectomy correlated with the induction of DNA synthesis. These studies suggest that TGF-beta1 may enhance HDAC1 binding to p130 in vivo, thereby inhibiting cdc25A gene expression. TGF-beta1 regulation of HDAC1/pocket protein associations may provide a link between chromatin remodeling proteins and cdk inhibition through induction of cdc25A in vivo.

Animals↗
PubMed1999

Induced differentiation of U937 cells by 1,25-dihydroxyvitamin D3 involves cell cycle arrest in G1 that is preceded by a transient proliferative burst and an increase in cyclin expression.

The hormonal form of vitamin D, 1,25-dihydroxyvitamin D3 [1, 25(OH)2D3], is a potent inhibitor of cellular proliferation as well as an inducer of differentiation of myeloid leukemic cells to macrophages. We have previously reported that a number of genes are upregulated by 1,25(OH)2D3 during myeloid differentiation, including the cyclin-dependent kinase (CDK) inhibitors p21, p27, 15, and p18, suggesting that cell cycle arrest and differentiation are tightly linked processes. We further explore here the relationship between growth inhibition and differentiation. We report that, upon 1, 25(OH)2D3 treatment, U937 cells exhibited an early proliferative burst followed by growth inhibition and subsequent differentiation. Although CDK levels remain constant throughout, this transient increase in proliferation was accompanied by increases in cyclin A, D1, and E protein levels. p21 and p27 levels were also elevated during both the proliferative burst and subsequent inhibition of cell growth. Ectopic overexpression of p21 and/or p27 in U937 cells, in the absence of hormone, resulted in an induction of the expression of monocyte/macrophage-specific markers, whereas overexpression of p15 and p18 had no effect, suggesting that a subset of CDK inhibitors are important for both growth arrest and differentiation and that an early increase in proliferation is somehow a prerequisite for subsequent differentiation. However, no such biphasic behavior was detected in cells that are growth inhibited by 1,25(OH)2D3 but do not differentiate, such as MCF-7 cells. Taken together, these results indicate that both growth stimulation and subsequent inhibition precede differentiation and involve induction of both cyclins and p21 and p27, whereas cell cycle arrest of differentiated cells can be achieved simply by elevations in CDK inhibitors.

Calcitriol↗
PubMed1999

Dyscalculia in the early stages of Alzheimer's disease.

OBJECTIVE: To study mathematical deficits in the early stages of Alzheimer's disease (AD). METHODS: Sixty-eight patients with mild AD and 242 normal controls (NC) received a standardized battery (EC 301-R) assessing number processing and calculation abilities. AD patients also received testing for language, memory, visuo-spatial and executive-attentional domains. RESULTS: Sixty-four AD patients (94.1%) showed impaired performances on the EC 301-R. Mathematical deficits were evident both on calculation and number processing skills. Performance on the single tasks was related to attentional-executive resources and to impaired number representations. Heterogeneous patterns of preserved/impaired mathematical abilities were also observed in single cases. CONCLUSION: Dyscalculia is an early sign of AD. It should be included among the reliable clinical hallmarks for the diagnosis of AD. Identification of dyscalculic symptoms in these patients requires composite assessment procedure.

Aged↗
PubMed1999

E2F and histone deacetylase mediate transforming growth factor beta repression of cdc25A during keratinocyte cell cycle arrest.

cdc25A is a tyrosine phosphatase that activates G1 cyclin-dependent kinases (Cdk's). In human keratinocytes, cdc25A expression is down-regulated after the initial drop in Cdk activity caused by cell exposure to the antimitogenic cytokine transforming growth factor beta (TGF-beta) or removal of serum factors. Here we show that the TGF-beta-inhibitory-response element in the cdc25A promoter maps to an E2F site at nucleotides -62 to -55 from the transcription start site. This site is not required for basal transcription in keratinocytes. We provide evidence that the cell cycle arrest program activated by TGF-beta in human keratinocytes includes the generation of E2F4-p130 complexes that in association with histone deacetylase HDAC1 inhibit the activity of the cdc25A promoter from this repressor E2F site. This mechanism is part of a program that places keratinocytes in the quiescent state following the initial drop in Cdk activity caused by cell exposure to TGF-beta.

Base Sequence↗
PubMed1998

Regulation of the cdk inhibitor p21 gene during cell cycle progression is under the control of the transcription factor E2F.

The control of cell cycle progression is orchestrated by an extraordinary diverse and dynamic in function group of proteins. Critical in the progression are the actions of the E2F family of transcription factors which regulate the expression of genes necessary for the G1/S transition and the WAF/CIP/KIP family of cdk inhibitors which can inhibit cell cycle progression. In this report, we have identified E2F binding sites in both the human and mouse p21 promoters that bind E2F protein complexes from nuclear extracts in a cell cycle-dependent manner. In ectopic expression experiments we determined that E2F1, but not E2F4, can strongly transactivate the human p21 gene through these E2F binding sites which are located in the -215/+1 region of the p21 gene. The transactivation of the p21 gene through regulatory elements within the -215/+1 region of the promoter was correlated with increased levels of endogenous E2F1 and p21 proteins at the G1/S boundary. The significance of transactivation of the p21 gene by E2F is that p21 function is important in cell cycle progression as well as for cell cycle arrest. Indeed, E2F-induced levels of p21 protein during the G1/ S transition is consistent with the recent findings demonstrating that p21 acts as an assembly factor for kinase active cyclin/cdk/p21 complexes.

Animals↗
PubMed1998

Depressive symptoms in adult coeliac disease.

BACKGROUND: Psychic symptoms and depression have been reported in coeliac disease (CD). The aim of this study was to explore depression in a large cohort of adult CD patients. METHODS: Depressive symptoms were evaluated in 92 adult coeliacs, 100 normal controls (NC), and 48 chronic persistent hepatitis (CPH) patients by means of a modified version of the Zung Self-Rating Depression Scale (M-SDS). CD patients were evaluated for the level of knowledge about CD and the compliance with diet. RESULTS: The M-SDS score differentiated CD patients from NC. Age at diagnosis and duration of and compliance with diet did not correlate with depression. Three main factors could be identified with the M-SDS: 'reactiveness', 'pessimism', and 'anhedonic-asthenic'. CONCLUSION: Depressive symptoms are a feature of CD; they are present to a similar extent in patients with childhood- and adulthood-diagnosed CD. The results underline the relevance of personal psychologic resources, which play a fundamental role in determining and sustaining depression.

Adult↗
PubMed1997

Regulated ectopic expression of cyclin D1 induces transcriptional activation of the cdk inhibitor p21 gene without altering cell cycle progression.

Cyclin D1 plays a key regulatory role during the G1 phase of the cell cycle and its gene is amplified and overexpressed in many cancers. To address the relationship between cyclin D1 and other cell cycle regulatory proteins, we established human glioma and rodent fibroblast cell lines in which cyclin D1 expression could be regulated ectopically with tetracycline. In both of these cell lines, we found that ectopic expression of cyclin D1 in asynchronously growing cells was accompanied by increased levels of the p53 tumor suppressor protein and the cyclin/cdk inhibitor p21. Despite the induction of these cell cycle inhibitory proteins, cyclin D1-associated cdk kinase remained activated and the cells grew essentially like that of the parent cells. Although growth parameters were unchanged in these cells, morphological changes were clearly identifiable and anchorage independent growth was observed in NIH3T3 cells. In a first step toward elaborating the mechanism for cyclin D1-mediated induction of p21 gene expression we show that co-expression of E2F-1 and DP-1 can specifically transactivate the p21 promoter. In support of these findings and a direct effect of E2F on induction of p21 gene expression a putative E2F binding site was identified within the p21 promoter. In summary, our results demonstrate that ectopic expression of cyclin D1 can induce gene expression of the cdk inhibitor p21 through an E2F mechanism the consequences of which are not to growth arrest cells but possibly to stabilize cyclin D1/cdk function.

3T3 Cells↗
PubMed1997

Repression of the CDK activator Cdc25A and cell-cycle arrest by cytokine TGF-beta in cells lacking the CDK inhibitor p15.

The activity of the cyclin-dependent kinases (CDKs) that control cell growth and division can be negatively regulated by tyrosine phosphorylation or by the binding of various CDK inhibitors. Whereas regulation by tyrosine phosphorylation is well documented in CDKs that function during mitosis, little is known about its role in the regulation of CDKs that act in the G1 phase of the cell cycle. In contrast, much evidence has accumulated on the regulation of G1 CDKs by CDK inhibitors. The cytokine TGF-beta inhibits growth by causing cell-cycle arrest as a result of increasing the concentration of the Cdk4/6 inhibitor p15(INK4B/MTS2) (refs 3, 4). Here we report that TGF-beta can also cause the inhibition of Cdk4 and Cdk6 by increasing their level of tyrosine phosphorylation. Tyrosine phosphorylation and inactivation of Cdk4/6 in a human mammary epithelial cell line are shown to result from the ability of TGF-beta to repress expression of the CDK tyrosine phosphatase Cdc25A. Repression of Cdc25A and induction of p15 are independent effects mediating the inhibition of Cdk4/6 by TFG-beta.

Carrier Proteins↗
PubMed1997

Optimal use of the 131-I-metaiodobenzylguanidine and cisplatin combination in advanced neuroblastoma.

Neuroblastoma (NB), a childhood radiosensitive tumor, is very aggressive and malignant, in its disseminated form, despite very intensive chemotherapy, prognosis continues to be dismal. Owing to its capacity to concentrate in NB lesions, large doses of 131-I-MIBG, have given very encouraging therapeutic results in patients resistant to conventional therapy as well as at diagnosis. We recently reported the first attempt in combination therapy (CO-TH) using 131-I-MIBG and cisplatin. This new form of CO-TH appears very effective in obtaining a rapid and excellent response in relapsed patients. In this report, we describe the results of further experience with CO-TH in disseminated NB. We have attempted to verify to what extent interaction between the effects of the two agents may produce therapeutic benefit, and we have sought the optimization of CO-TH use. Three stage IV NB patients were treated with CO-TH. The following treatment schedule, was planned: day 1, cisplatin 50 mg/m3 i.v. over 6 h; day 2, 131-I-MIBG 100-130 mCi at high specific activity (-1.1 Gbq/mg) i.v. over 6 h followed, a week later, by the same treatment combination. The therapeutic results were encouraging. However, hematological toxicity continued to represent a major limiting factor. In view of the overall effectiveness of CO-TH, at the price of lasting hematological toxicity, it may be indicated as a consolidation regimen some time before conditioning chemotherapy for autologous bone marrow transplantation.

3-Iodobenzylguanidine↗
PubMed1996

Transcriptional activation of the human p21(WAF1/CIP1) gene by retinoic acid receptor. Correlation with retinoid induction of U937 cell differentiation.

We reported previously that the induced differentiation of the myelomonocytic cell line U937 by vitamin D3 is facilitated by the transcriptional induction of the p21(WAF1/CIP1) gene by the vitamin D3 receptor (Liu, M., Lee, M.-H., Cohen, M., and Freedman, L. P. (1996) Genes Dev. 10, 143-153). Retinoic acid (RA), a physiological metabolite of vitamin A, is also a potent inducer of differentiation of several cell types, including myeloid leukemic cells. Like vitamin D3, RA acts through a subfamily of nuclear hormone receptors, RARs and RXRs (retinoid X receptors), which regulate the expression of target genes by binding to specific DNA elements and modulating transcription initiation. In this report we demonstrate that the gene encoding p21 is also a RA-responsive target gene, and we describe a functional RA response element in this gene's promoter which is required to confer RA induction through RAR.RXR heterodimers. These results correlate the RA induction of monocytic differentiation of U937 cells with the transcriptional activation of the p21 gene and suggest a role for this cyclin/cyclin-dependent kinase complex inhibitor in facilitating this differentiation pathway.

Cell Differentiation↗
PubMed1996

Cyclin-dependent kinase inhibitor p57KIP2 in soft tissue sarcomas and Wilms'tumors.

Mammalian cyclin-dependent kinase inhibitors fall into two families, the INK4 and the CIP/KIP. The CIP/KIP family comprises three structurally related members, including p21CiP1/WAF1, p27KIP1, and p57KIP2. These proteins are all capable of inhibiting the progression of the cell cycle by binding and inhibiting G(1) cyclin/cyclin-dependent kinase complexes. In humans, p57KIP2 is expressed specifically in skeletal muscle, heart, brain, kidney, and lung. Human KIP2 resides in 11p15.5, a chromosomal region that is a common site for loss of heterozygosity in certain sarcomas, Wilms' tumors, and tumors associated with the Beckwith-Wiedemann syndrome. Because of the function, selective expression, and chromosomal location of p57KIP2, we undertook the present study to search for potential mutations of KIP2 in a cohort of 126 tumors composed of 75 soft tissue sarcomas and 51 Wilms' tumors. The KIP2 gene was characterized by Southern blot, comparative multiplex PCR, PCR -single-strand conformational polymorphism, and DNA sequencing assays in these neoplasms. Deletions of the KIP2 gene or point mutations at the region encoding the cyclin-dependent kinase inhibitory domain were not found in the tumors analyzed. The absence of KIP2 mutations might indicate that these tumors arise due to defects at a closely linked but separate locus. Alternatively, similarly to the mouse homologue, inactivation of KIP2 could occur via genomic imprinting.

Adult↗