Gaetano De Rosa

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.

Expression of COX-2, mPGE-synthase1, MDR-1 (P-gp), and Bcl-xL: a molecular pathway of H pylori-related gastric carcinogenesis.

Helicobacter pylori up‐regulates cyclo‐oxygenase‐2 (COX‐2) expression, which in turn is involved in tumourigenesis. Recently, a causal link between COX‐2 and multidrug resistance 1 (MDR‐1) gene expression, implicated in cancer chemoresistance, has been demonstrated. Thus, the expression of COX‐2 and the downstream enzyme involved in PGE2 biosynthesis, microsomal PGE‐synthase1 (mPGES1), was correlated with P‐gp, the product of MDR‐1, and the anti‐apoptotic protein, Bcl‐xL, in gastric biopsies from patients with H pylori infection and in patients with gastric cancer. In a retrospective analysis of endoscopic and pathology files, 40 H pylori‐negative patients (Hp−), 50 H pylori‐positive patients who responded to eradication therapy (Hp+R), 84 H pylori‐positive patients who did not respond to eradication therapy (Hp+NR), and 30 patients with gastric cancer (18 intestinal and 12 diffuse types) were selected. COX‐2, mPGES1, P‐gp, and Bcl‐xL were detected by immunohistochemistry. COX‐2, mPGES1, P‐gp, and Bcl‐xL expression was undetectable in gastric mucosa from Hp− patients. By contrast, COX‐2 and mPGES1 expression was detected in 42% and 44% of Hp+R patients, respectively, and in up to 66% (range 63–66%) of Hp+NR patients (p < 0.05). The expression of COX‐2 and mPGES1 correlated significantly (p < 0.0001) with that of P‐gp and Bcl‐xL. High levels of COX‐2, mPGES1, P‐gp, and Bcl‐xL expression were found in intestinal‐type gastric cancer samples. In conclusion, H pylori‐dependent induction of COX‐2 and mPGES1 is associated with enhanced production of P‐gp and Bcl‐xL that may contribute to gastric tumourigenesis and resistance to therapy. Copyright

Efficacy and age-related effects of nitric oxide-releasing aspirin on experimental restenosis

Restenosis after percutaneous transluminal coronary angioplasty is caused by neointimal hyperplasia, which involves impairment of nitric oxide (NO)-dependent pathways, and may be further exacerbated by a concomitant aging process. We compared the effects of NO-releasing-aspirin (NCX-4016) and aspirin (ASA) on experimental restenosis in both adult and elderly rats. Moreover, to ascertain the efficacy of NCX-4016 during vascular aging, we fully characterized the release of bioactive NO by the drug. Sprague–Dawley rats aged 6 and 24 months were treated with NO releasing-aspirin (55 mg/kg) or ASA (30 mg/kg) for 7 days before and 21 days after standard carotid balloon injury. Histological examination and immunohistochemical double-staining were used to evaluate restenosis. Plasma nitrite and nitrate and S-nitrosothiols were determined by a chemiluminescence-based assay. Electron spin resonance was used for determining nitrosylhemoglobin. Treatment of aged rats with NCX-4016 was associated with increased bioactive NO, compared with ASA. NO aspirin, but not ASA, reduced experimental restenosis in old rats, an effect associated with reduced vascular smooth muscle cell proliferation. NCX-4016, but not ASA, was well tolerated and virtually devoid of gastric damage in either adult or old rats. Thus, impairment of NO-dependent mechanisms may be involved in the development of restenosis in old rats. We suggest that an NCX-4016 derivative could be an effective drug in reducing restenosis, especially in the presence of aging and/or gastrointestinal damage.

Estrogen receptor β expression in human prostate tissue

Abstract Estrogen receptor subtype β (ERβ) is highly expressed in rat prostate epithelium, but its presence in human prostate needs to be confirmed. Here we investigated the expression of ERβ in five benign (normal and/or hyperplastic) and 10 malignant (Gleasons’ score 2–7) prostate tissue specimens using immunohistochemistry. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded tissue sections, using a commercially available ERβ polyclonal antibody developed against the C-terminal amino acid residue. Nuclear ERβ expression was found in the nuclei of glandular epithelium of benign prostate tissue specimens; faint nuclear ERβ positivity was also present in a few stromal cells around normal epithelium. Nuclear ERβ specific immunostaining was undetectable in all prostate cancer sections.

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.

Modulation of in vivo growth of thyroid tumor-derived cell lines by sense and antisense vascular endothelial growth factor gene.

Vascular endothelial growth factor A (VEGF) is a potent mitogen for endothelial cells in vitro and promotes neo-angiogenesis in vivo. VEGF overexpression occurs in most human malignancies including thyroid carcinomas in which elevated VEGF expression is associated with a high tumorigenic potential. To investigate the role of VEGF in angiogenesis associated with development of thyroid carcinomas, we constitutively expressed VEGF121 into a poorly tumorigenic cell line (NPA) expressing minimal levels of endogenous VEGF. Here we report that VEGF overexpressing NPA cells showed the same growth potential as untransfected NPA in vitro but formed well-vascularized tumors when injected subcutaneously into nude mice with markedly reduced latency compared to parental cells. A complementary approach was to suppress VEGF expression in a highly tumorigenic anaplastic cell line (ARO) by the transfection of an antisense construct. Antisense-transfected ARO cells expressed reduced constitutive levels of VEGF, showed the same growth potential as untransfected ARO cells in vitro and formed small tumors characterized by minimal vascularization, extensive necrosis and longer latency compared to parental or vector-transfected ARO cells in vivo. Finally, we investigated the expression of both VEGF tyrosine kinase receptors (Flt-1 and Flk-1/KDR) in tumor specimens by RT – PCR. Expression of (Flt-1 and Flk-1/KDR) was low in tissue specimens derived from NPA tumors, but was found enhanced in NPA VEGF tumors; conversely, the expression of VEGF receptors was high in tissue specimens derived from ARO tumors but was decreased in tumors derived from VEGF depleted ARO cells. These results clearly demonstrate that VEGF indirectly promotes the growth of thyroid tumors by stimulating angiogenesis.

Expression of teratocarcinoma-derived growth factor-1 (TDGF-1) in testis germ cell tumors and its effects on growth and differentiation of embryonal carcinoma cell line NTERA2/D1.

The teratocarcinoma-derived growth factor-1 (TDGF-1) gene codes for a 188-aminoacid glycoprotein that shares structural homology with the epidermal growth factor (EGF) family of growth factors. TDGF-1 is highly expressed in the undifferentiated embryonal carcinoma stem cell line NTERA2 clone D1 (NT2/D1) and its expression is downregulated in response to differentiating agents such as retinoic acid (RA) and hexamethylen-bisacetamide (HMBA). To assess the role of TDGF-1 in the onset and/or progression of human germ cell tumors, we analysed TDGF-1 expression by Northern blot and immunostaining in a panel of 59 human germ cell tumors of different histological origins. We show that TDGF-1 expression is markedly elevated in a subset of human testicular germ cell tumors as compared to normal testes. TDGF-1 overexpression occurs in about 100% of tumors with non-seminomatous phenotype, such as embryonal carcinomas and malignant undifferentiated teratocarcinomas. To address the questions of how TDGF-1 (previously called CRIPTO) may affect the growth and/or the differentiation of embryonal carcinoma cells, we have characterized the effects of exogenous recombinant TDGF-1 protein on the proliferation rate and differentiation potential of NT2/D1. Exogenous TDGF-1 protein stimulated DNA synthesis and cell proliferation in both undifferentiated and differentiated NT2/D1 cells. However, TDGF-1 protein treatment was unable to block differentiation induced by both RA and HMBA. These results suggest that TDGF-1 growth factor may represent an autocrine growth factor that may be involved in the process of development of testicular neoplasms.

Microstructural Disorders of Tunica Albuginea in Patients Affected by Peyronie’s Disease with or without Erection Dysfunction

Peyronies disease, the etiology of which remains unknown, is characterized by a focal or multifocal disorder of penile tunica albuginea. An excessive collagen deposition gives rise to the formation of the plaque, which is fibrotic first and then becomes calcific. Typical symptoms of the disease are painful erection, pathological bending of the erect penis and impotence at the more advanced stages (43% of the cases). There is evidence that the tunica albuginea has a fundamental role in the erection mechanism. We evaluated the tunica albuginea of patients suffering from Peyronies disease, with or without impotence, and found progressive disorders of the microstructure in areas that were not affected by fibrocalcific formations. There was a significant decrease (p < 0.0001) of elastic fiber concentration (55.05 +/- 23.83 per high power field) in patients with Peyronies disease compared to the concentration in the tunica albuginea of a control group (128.50 +/- 11.79 per high power field). Moreover, when the elastic fiber concentration in the tunica albuginea of patients Peyronies disease and normal erection (71.36 +/- 12.00 per high power field) was compared to the concentration in the tunica albuginea of those with Peyronies disease and impotence (33.14 +/- 4.84 per high power field) a significant difference was noted (p < 0.0001).