Gelsomina Mansueto

Deletion of the p66Shc longevity gene reduces systemic and tissue oxidative stress, vascular cell apoptosis, and early atherogenesis in mice fed a high-fat diet

Several experimental and clinical studies have shown that oxidized low-density lipoprotein and oxidation-sensitive mechanisms are central in the pathogenesis of vascular dysfunction and atherogenesis. Here, we have used p66Shc−/− and WT mice to investigate the effects of high-fat diet on both systemic and tissue oxidative stress and the development of early vascular lesions. To date, the p66Shc−/− mouse is the unique genetic model of increased resistance to oxidative stress and prolonged life span in mammals. Computer-assisted image analysis revealed that chronic 21% high-fat treatment increased the aortic cumulative early lesion area by ≈21% in WT mice and only by 3% in p66Shc−/− mice. Early lesions from p66Shc−/− mice had less content of macrophage-derived foam cells and apoptotic vascular cells, in comparison to the WT. Furthermore, in p66Shc−/− mice, but not WT mice, we found a significant reduction of systemic and tissue oxidative stress (assessed by isoprostanes, plasma low-density lipoprotein oxidizability, and the formation of arterial oxidation-specific epitopes). These results support the concept that p66Shc−/− may play a pivotal role in controlling systemic oxidative stress and vascular diseases. Therefore, p66Shc might represent a molecular target for therapies against vascular diseases.

Somatostatin receptor type 2A immunohistochemistry in neuroendocrine tumors: a proposal of scoring system correlated with somatostatin receptor scintigraphy

Typing somatostatin receptor expression in neuroendocrine tumors is of relevance to target somatostatin analogue-based diagnostic approach and treatment. The expanding use of immunohistochemistry to detect somatostatin receptors is to date not paralleled by an accurate methodological setting and standardized interpretation of the results. A multicentric study was designed to compare somatostatin receptor immunohistochemical expression with in vivo scintigraphic data and verify its usefulness in the clinical management of neuroendocrine tumors. After methodological setting by testing different somatostatin receptor antibodies, 107 cases of neuroendocrine tumors with available somatostatin receptor scintigraphy data and pathological material were retrospectively analyzed for somatostatin receptor types 2A, 3 and 5 immunohistochemical expression, and compared with scintigraphic images and, whenever available, with the clinical response to somatostatin analogue treatment. Restricting ‘positive cases’ to the presence of a membrane pattern of staining, an overall somatostatin receptor type 2A immunohistochemistry/somatostatin receptor scintigraphy agreement of 77% (χ2 test P<0.0001) was reached. Lower concordance ratios were detected in preoperative and metastatic tumor samples, possibly as a consequence of somatostatin receptor expression heterogeneity. Pure somatostatin receptor type 2A cytoplasmic staining showed poor correlation with somatostatin receptor scintigraphy (54% concordance rate). The immunohistochemical detection of somatostatin receptor types 3 and 5, which showed almost exclusively a cytoplasmic pattern, did not improve the concordance with scintigraphic data. In a pilot series, somatostatin receptor type 2A immunohistochemistry correlated with clinical response in 75% of cases. In conclusion, we propose a scoring system for somatostatin receptor type 2A immunohistochemistry in neuroendocrine tumors correlated with in vivo data, based on the evidence that only membrane (rather that cytoplasmic) staining should be considered for a reliable, standardized and clinically relevant report.

The protein stability and transcriptional activity of p63α are regulated by SUMO-1 conjugation

Post-translational modification of proteins by the ubiquitin-like molecule SUMO-1 regulates their stability and activity with crucial implications for many cellular processes. Here we show that p63α, but not p63α and α, is sumoylated in vitro and in vivo at a single lysine residue, K637, in the post-SAM domain. SUMO-1 attachment targets ΔNp63α for proteasome mediated degradation while it does not influence p63α intracellular localization, as wild-type protein and a mutant carring the K637 mutated into arginine (K637R), have the same nuclear localization. Four natural p63 mutations, falling within the SAM and post-SAM domain of p63α, were found to be altered in their sumoylation capacity. The transcriptional activities of the natural mutants and of K637R were strongly increased compared to that of wild type p63, suggesting that sumoylation has a negative effect on p63 driven transcription. The findings that ΔNp63α protein levels are regulated by SUMO-1 and that this regulation is altered in natural p63 mutants, suggest that SUMO conjugation to p63 plays a critical role in regulating the biological activity of p63.

Chronic treatment with sulfhydryl angiotensin-converting enzyme inhibitors reduce susceptibility of plasma LDL to in vitro oxidation, formation of oxidation-specific epitopes in the arterial wall, and atherogenesis in apolipoprotein E knockout mice

The effects of chronic treatment with the new sulfhydryl angiotensin-converting enzyme (ACE)-inhibitor, zofenopril, in comparison with the classical sulfhydryl ACE-inhibitor captopril or enalapril or placebo on the development of atherosclerosis were determined in apolipoprotein-E knockout (apoE(-/-)) mice. Groups of 2-month-old male mice received either placebo (N=10), 0.05 mg/kg/day of zofenopril (N=10), 1 mg/kg/day of zofenopril (N=10), 5 mg/kg/day of captopril (N=10) or 0.5 mg/kg/day of enalapril (N=8). After 29 weeks of treatment, computer-assisted imaging analysis revealed that zofenopril reduced the aortic cumulative lesion area by 78% at 0.05 mg/kg/day and by 89% at 1 mg/ml/day of zofenopril compared to that of the placebo (P<0.0001). Captopril reduced by 52% aortic lesions compared to placebo (P<0.01 vs. placebo; P<0.05 vs. zofenopril at both doses). Enalapril did not reduce aortic lesions. Furthermore, 0.05 mg/kg/day of zofenopril reduced susceptibility of plasma LDL to in vitro oxidation compared to captopril, enalapril or placebo, as shown by significant reduction of malondialdehyde content (P<0.001 vs. placebo or enalapril; P<0.05 vs. captopril), as well as by the prolongation of lag-time (P<0.01 vs. placebo or enalapril P<0.05 vs. captopril). More importantly, mice treated with 1 mg/ml/day of zofenopril had a significant decrease in the intimal immunohistochemical presence of oxidation-specific epitopes on oxLDL (NA59 monoclonal antibody, P<0.01), macrophages derived foam cells (F4/80 monoclonal antibody, P<0.05) and native LDL (NP monoclonal antibody, P<0.01) compared to placebo, captopril or enalapril. Thus, chronic treatment with the new sulfhydryl ACE-inhibitor zofenopril has antiatherosclerotic and antioxidant effects in the arterial wall of hypercholesterolemic apoE(-/-) mice. This protection was significantly higher than that reached with captopril and at lower doses of the drug. Treatment with 0.5 mg/kg/day of enalapril did not provide any protective effect.

Clinical response, vascular change, and angiogenesis in gonadotropin-releasing hormone analogue-treated women with uterine myomas

Objective: Basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF) are involved in the pathogenesis of leiomyomas and influence angiogenesis, which is necessary for growth of leiomyomas. Gonadotropin-releasing hormone analogue (GnRH-a) treatment might modify the growth factor expression and the blood supply in myomas. We investigated the effects of GnRH-a treatment on some clinical parameters, on the immunohistochemical expression of bFGF, VEGF, and PDGF, and on the vasculature of leiomyomas. Methods: Thirty-one women were treated with leuprolide acetate for 3 months; 55 untreated patients formed the control group. Hematologic parameters were assessed at the admission, after GnRH-a treatment, and after surgery. Uterine volume was evaluated by ultrasonography. The immunoexpression of bFGF, VEGF, and PDGF and of the endothelial markers CD34 and CD105, as well as the vascular pattern, were studied in leiomyomas, comparing treated and untreated patients. Results: Hematologic parameters improved and uterine volumes decreased after GnRJH-a treatment. The immunoexpression of bFGF, VEGF, and PDGF decreased in treated myomas, together with the total number of vessels and the angiogenetic vessels. Conclusion: This study confirms the clinical response of uterine shrinkage after GnRH-a treatment. A pathogenetic role of bFGF, VEGF, and PDGF in myoma growth and vascularization is suggested. Finally, this study indirectly confirms the importance of the vasculature in leiomyoma growth.

Overexpression of the Cytokine Osteopontin Identifies Aggressive Laryngeal Squamous Cell Carcinomas and Enhances Carcinoma Cell Proliferation and Invasiveness

Purpose: Osteopontin is a secreted cytokine that binds to the cell surface CD44v6 receptor. We studied osteopontin and CD44v6 expression in laryngeal squamous cell carcinomas and correlated osteopontin expression levels with clinicopathologic tumor features. Experimental Design: We used immunohistochemistry, immunoblotting, and reverse transcription-PCR to study osteopontin expression in 58 laryngeal squamous cell carcinomas. Cultured squamous carcinoma cells were treated with exogenous osteopontin or with RNA interference to knockdown osteopontin expression. Results: Osteopontin expression was higher in all the invasive carcinomas than in patient-matched normal mucosa. Its expression levels were significantly correlated with tumor stage and grade and with the presence of lymph node and distant metastases. Osteopontin positivity was negatively correlated with overall survival (P = 0.03). Osteopontin expression was paralleled by intense cell surface reactivity for CD44v6. Treatment of squamous carcinoma cells with recombinant osteopontin sharply increased proliferation and Matrigel invasion in comparison with the untreated cells parallel to activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase/mitogen-activated protein kinase signaling cascade. Osteopontin knockdown by RNA interference, anti-CD44 antibodies, and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase inhibition prevented these effects. Conclusions: These results identify osteopontin as a marker and a potential therapeutic target in cases of aggressive laryngeal squamous cell carcinomas.

The biological characterization of neuroendocrine tumors: The role of neuroendocrine markers

Neuroendocrine tumors (NET) may originate in different organs, from cells embriologically different but expressing common phenotypic characteristics, such as: the immuno-re-activity for markers of neuroendocrine differentiation (defined as “pan-neuroendocrine”), the capacity to secrete specific or aspecific peptide and hormones and the expression of some receptors, that are at the basis of the current diagnostic and therapeutical approach, peculiar to these tumors. NET have been conventionally distinguished in functioning, when associated with a recognized clinical endocrine syndrome, and non-functioning. However, this terminology may be misleading, since the great majority of NET may secrete neuroendocrine peptides, which can be employed as clinical markers for both diagnosis and follow-up. On the other hand, tissue immuno-reactivity for specific hormones does not always reflect secretory activity of the tumor cells. Finally, receptors and genetic markers are acquiring a relevant role in the characterization of NET, both improving knowledge of biology and physiopathology of NET, as well as in developing specific strategies to establish an early diagnosis and targeted therapies, to adopt prophylactic strategies in familial forms, and to identify more efficacious targets for therapy in the future.

p66Shc Deletion Confers Vascular Protection in Advanced Atherosclerosis in Hypercholesterolemic Apolipoprotein E Knockout Mice

Previous studies showed that p66(Shc-/-) mice on a very-high-fat diet (HFD) had reduced oxidative stress, foam cell, and early atherosclerotic lesion formation. Here, the authors have used hypercholesterolemic apolipoprotein E (ApoE(-/-)) mice to investigate the role of p66Shc deletion in advanced atheroma. The authors generated mice deficient of both ApoE and p66Shc genes (ApoE(-/-) /p66(Shc-/-)). They used microsatellite polymerase chain reaction (PCR) analysis to analyze the genetic background and considered only animals with a constant percentages of C57B6L and 129SV background strands (it was obtained the 50.3% +/- 6.4% of C57B6L background). Computer-assisted analysis revealed that advanced atherosclerotic lesions in ApoE(-/-)/p66(Shc+/+) were significantly larger than those observed in ApoE(-/-)/p66(Shc-/-). Accordingly, the lipid-laden macrophage foam cells and oxidation-specific epitopes in ApoE(-/-)/p66(shc+/+) HFD-treated groups were higher than those observed in normal diet (ND)-treated groups. Thus, p66(Shc-/-) plays an important protective role also against advanced atherosclerotic lesion formation. Finally, the authors have used microarray to investigate major changes in gene expression in aortas of mice with ApoE(-/-)/p66(Shc-/-) background treated with a very HFD in comparison to ApoE(-/-)/p66(Shc+/+) (these data have been confirmed by by real-time PCR and immunohistochemistry). DAVID (Database for Annotation, Visualization and Integrated Discovery) analysis revealed that CD36 antigen (CD36), tissue inhibitor of metalloproteinase 2 (TIMP2), apolipoprotein E (ApoE), acetyl-coenzyme A acetyltransferase 1 (ACAT1), and thrombospondin 1 (THBS1) can be involved in p66 deletion-dependent vascular protection through the adipocytokine/lipid signaling pathway.

Diagnostic and prognostic implications of the World Health Organization classification of neuroendocrine tumors

Background: Neuroendocrine differentiation of tumors is often difficult to establish. In the same manner, the evaluation of the prognostic role of neuroendocrine differentiation may constitute a relevant clinical problem. Although different classifications are used for neuroendocrine tumors (NET) of different origin, the last World Health Organization (WHO) classification of NET, originally proposed for gastroenteropancreatic tumors, has proved to be a practical tool to allow pathologists to uniform the diagnoses and re-classify these tumors into 3 main categories. Aim: The present study was carried out in order to evaluate diagnostic and prognostic implications of NET reclassification according to the last WHO classification of NET. Materials and methods: Thirty-one tumors with an initial diagnosis referable to a NET achieved before 1999 were independently evaluated by 3 pathologists on the basis of the 2000 WHO classification of NET. Immunohistochemistry for panneuroendocrine markers and Ki-67 was also performed in all cases. Results: Twelve, 14, and 4 tumors were respectively reclassified as well-differentiated NET, well-differentiated neuroendocrine carcinoma and poorly differentiated neuroendocrine carcinoma; 1 tumor was reclassified as mixed endocrine-exocrine tumor. Two or more neuroendocrine markers were expressed in all NET regardless of histotype, differentiation degree, and site of primary tumor. After revision, 10 of the 31 tumors under study (32%) changed histo-prognostic category when compared to the initial diagnosis. Ki-67 score was the best predictor of survival at the multivariate analysis. Conclusion: The WHO classification is suitable to accurately reclassify tumors with an initial diagnosis referable to a NET and to separate these tumors in 3 well-distinct histo-prognostic categories with relevant clinical implications. Ki-67 score seems to be a better predictor of survival than the degree of differentiation.

Loss of oestrogen receptor β, high PCNA and p53 expression and aneuploidy as markers of worse prognosis in ovarian granulosa cell tumours

Aims:  Ovarian granulosa cell tumour (OGCT) is a sex‐cord stromal tumour with a general trend toward late relapse and/or metastasis. However, mortality rate corrected for long‐term follow‐up shows that about 50% of patients die within 20 years of diagnosis. Classical clinicopathological parameters are unable to predict the biological behaviour of OGCT. The involvement of a recently characterized subtype of oestrogen receptor, ERβ, in ovarian carcinogenesis has been hypothesized.