S Lai

HLA-G expression and role in advanced-stage classical Hodgkin lymphoma.

Non-classical human leucocyte antigen (HLA)-G class I molecules have an important role in tumor immune escape mechanisms. We investigated HLA-G expression in lymphonode biopsies taken from 8 controls and 20 patients with advanced-stage classical Hodgkin lymphoma (cHL), in relationship to clinical outcomes and the HLA-G 14-basepair (14-bp) deletion-insertion (del-ins) polymorphism. Lymphnode tissue sections were stained using a specific murine monoclonal HLA-G antibody. HLA-G protein expression was higher in cHL patients than controls. In the group of PET-2 positive (positron emission tomography carried out after 2 cycles of standard chemotherapy) patients with a 2-year progression-free survival rate (PFS) of 40%, we observed high HLA-G protein expression within the tumor microenvironment with low expression on Hodgkin and Reed-Sternberg (HRS) cells. Conversely, PET-2 negative patients with a PFS of 86% had higher HLA-G protein expression levels on HRS cells compared to the microenvironment. Lower expression on HRS cells was significantly associated with the HLA-G 14-bp ins/ins genotype. These preliminary data suggest that the immunohistochemical pattern of HLA-G protein expression may represent a useful tool for a tailored therapy in patients with cHL, based on the modulation of HLA-G expression in relation to achievement of negative PET-2.

Activated Notch1 expression is associated with angiogenesis in cutaneous melanoma.

An early event in melanocytic tumor growth is the upregulation of Notch signaling. When an active form of Notch1 is overexpressed in primary human melanocytes, it increases cell growth, survival and invasive properties, promoting melanoma progression. Recent evidence suggested that tumor initiation and growth are driven by a subset of tumor-initiating cells termed cancer stem cells. Notch1 plays a predominant role in the maintenance of melanoblasts, including melanocyte stem cells, by preventing initiation of apoptosis. Moreover, the importance of Notch1 in the regulation of tumor angiogenesis is supported by growing evidence in various cancers. Nestin has been widely used as a marker for melanocyte stem cells as well as an angiogenic marker to evaluate neovascularity of endothelial cells in tumors. To gain an insight into the impact of Notch1 activation on the maintenance of melanocyte stem cells and angiogenesis in melanoma, the expression levels of activated Notch1 and nestin were analyzed by immunohistochemistry in 114 primary cutaneous melanomas and 35 lymph node metastases. Activated Notch1 and nestin expression was also evaluated in four dysplastic melanocytic nevi. This study provides evidence that activated Notch1 is overexpressed in cutaneous melanoma, in tumor cells as well as in microvessel endothelium, and that it can promote tumor angiogenesis. Indeed, the overexpression of activated Notch1 in both tumor and vascular endothelial cells was significantly associated with microvascular density in melanoma samples. Thus, activated Notch1 inhibitors may provide a therapeutic strategy in the treatment of melanoma by blocking tumor-associated vascularization.

Nestin and vimentin colocalization affects the subcellular location of glucocorticoid receptor in cutaneous melanoma

Aims:  Nestin (a neuronal stem cell/progenitor cell marker of central nervous system development), vimentin (which is ubiquitously expressed in mesenchymal cells), and the glucocorticoid receptor (GR, which is involved in the immune response, cell proliferation, and apoptosis) have been shown to interact in embryonic and undifferentiated tissues in modulating cell proliferation. The aim of this study was to analyse nestin, vimentin and GR expression in tumour tissue (melanoma), and their association with clinicopathological variables, to evaluate any effect on tumour progression.

Association between the ACE insertion/deletion polymorphism and pterygium in Sardinian patients: a population based case–control study

Objective The purpose of the study was to examine whether the insertion (I) and/or deletion (D) polymorphism of ACE confers susceptibility to primary pterygium in Sardinian patients in a case–control study. Methods and results Polymorphism genotyping was performed by nested PCR using genomic DNA extracted from the whole peripheral blood of participants with (n=251) and without (n=260) pterygium. DD, ID and II genotype frequencies were: 48%, 39% and 13%, respectively, for patients with pterygium, and 15%, 40% and 44%, respectively, for the control group. A statistically significant difference was found between the pterygium and control groups for the ACE I/D polymorphism (p<0.001). Moreover, a statistically significant difference was found between the DD and II groups (p<0.01; OR=10.49; 95% CI 6.18 to 17.79), DD+ID versus II group (p<0.01; OR=5.23; 95% CI 3.37 to 8.13) and DD versus ID groups (p<0.01; OR=3.21; 95% CI 2.04 to 5.04). Conclusions Statistical analysis showed that the DD genotype is associated with an increased risk of developing pterygium, and with a good chance that the D allele may play an important role in the development of disease.

Association between the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and pterygium in Sardinian patients

Pterygium is a common ocular surface disorder characterized by proliferation, inflammatory infiltrates, fibrosis, angiogenesis and extracellular matrix breakdown. Epidemiological studies indicate exposure chronic to UVB light as the most important risk factor for the development of pterygium. The Angiotensin Converting Enzyme (ACE) is the major component of the Renin-angiotensin system (RAS). It converts the inactive decapeptide Angiotensin I (Ang I) to the active octapeptide Angiotensin II (Ang II). Ang II is the most potent vasoconstrictor and stimulant of the aldosterone release. Recent discoveries have demonstrated that Ang II is also involved in cell proliferation, apoptosis, angiogenesis and tissue fibrosis. Moreover, it acts as growth factor and participates in inflammatory responses. The gene encoding ACE is mapped on chromosome 17q23; it contains 25 introns and 26 exons and shows a polymorphism characterized by the presence (insertion, I) or absence (deletion, D) of a 287-bp Alu sequence of DNA in intron 16. The presence or absence of Alu sequence in the ACE gene leads to the D/D, I/D and I/I genotypes. Novel studies have reported that the absence or presence of specific ACE I/D polymorphisms within ACE gene in several illnesses, such as cardiovascular diseases and breast cancer, can confer increased risk to develop the pathologies. Due to these evidences and the pterygium features, the aim of our study is to evaluate the ACE I/D gene polymorphism type in a group of Sardinia pterygium patients and to establish the possible correlation between ACE-type polymorphism and the development of pterygium in a case-control study.

Immunohistochemical detection of progenitor cells in pterygium

Pterygium is a degenerative and hyperplastic ocular surface disorder characterized by excessive cell proliferation, inflammation, fibrosis, extracellular matrix remodelling and angiogenesis. Several factors have been thought to be involved in the development of pterygium, however the exact mechanism of its pathogenesis is still unclear. Nestin is almost an acronym for “neuroepithelial stem cell protein”. It is an intermediate filament (IF) protein expressed in proliferating cells during the developmental stages in a variety of embryonic and fetal tissues. It is also expressed in some adult stem/progenitor cell populations, such as newborn vascular endothelial cells and it is reactivated in response to injuries or other pathological conditions. CD34 is a hematopoietic progenitor antigen expressed on hematopoietic progenitors as well as on small vessels endothelial cells and embryonic fibroblasts. CD34 is thought to function as an adhesion molecule for early hematopoietic progenitors mediating the attachment of stem cells to extracellular matrix or stromal cells. Some authors have already demonstrated the presence of some stemness markers in pterygial tissues, suggesting the involvement of bone marrow originated stem cells in the pathogenesis of pterygium. The aim of the present study was to evaluate, by immunohistochemistry on formalin-fixed and paraffin embedded sections of primary pterygium, the presence of some more stem cells markers, such as nestin and CD34 in order to support the classification of pterygium as proliferative disorder. The results will be discussed.

Glucorticoid receptor in human cutaneous melanoma: immunohistochemical and immunofluorescence study

GR is a nuclear receptor which, when activated by its specific ligand, can act as a transcription factor that binds to glucocorticoid response elements (GRE) or negative GRE. It affects inflammatory responses, differentiation and cell proliferation. The ligand activated glucocorticoid receptor induces a G1 cell cycle arrest or apoptosis in immature thymocytes and impairs proliferation of fibroblasts of undifferentiated mammary epithelial cells. It impairs proliferation and differentiation of neural progenitor cells in vivo and in vitro. Glucocorticoids are widely used in cancer therapy and have cell type-specific pro- or antiapoptotic effects. In melanoma, however, the antitumor activity of glucocorticoids remains an open question. A recent report demonstrated that in mouse embryo tissue and in human undifferentiated cells, cytoplasmic accumulation of GR is determined by nestin in conjunction with vimentin, copolymerised into an intermediate filament system, and that this anchoring of GR to the nestin/vimentin etheromeric complex is related to the maintenance of a high proliferation rate. The aim of this study was to analyse the expression of subcellular GR in cutaneous melanoma by immunofluorescence, immunohistochemistry and laser scanning confocal microscopy and to evaluate any effect in melanoma progression. The results will be discussed.

Association of nestin with anti-apoptotic and tumor suppressor factors in human breast cancer

Human breast carcinoma is a heterogeneous disease embracing different phenotypes with different biological characteristics. Transcriptional profiling has identified five breast cancer subtypes, of which the “basal epithelial” is the most aggressive, with a predilection for younger women, and correlates with poor prognosis. Nestin, an intermediate filament protein, was originally identified as a marker of neuroepithelial stem/progenitor cells in the brain. Recently, it was observed that nestin is expressed in basal/myoepithelial cells of the normal mammary gland and was also later found in cancer stem like cells of many tumors. Some studies showed that nestin is robustly immunohistochemically expressed in basal epithelial and triple negative breast tumors and that its expression correlates with survival patients. The increased expression of survivin, a member of the inhibitor-of-apoptosis (IAP) protein family, has been demonstrated to be associated with resistance to apoptosis. It has been reported that survivin and other IAP proteins cooperate to activate kinase cascades that control cell motility, thus stimulating tumour cell invasion and promoting metastasis. This mechanism seems to play a central role in breast cancer progression and resistance to treatment. The p53 protein represents the final effector of the p14CDKN2AMDM2 pathway; in majority of human cancers, the TP53 gene is functionally inactivated. Lack or reduced expression levels of the p53 protein seem to be associated with a defective apoptotic response to genotoxic damage and, thus, to anticancer agents. In this study, we evaluated the immunohistochemical expression of nestin in association with an anti-apoptotic protein, such as survivin, and a tumor suppressor factor, such as p53, and with Ki-67 proliferation index in bioptic samples of T4 breast tumors. The results will be discussed.

ACE I and ACE II: immunohistochemical study in primary pterygium

Pterygium is a common conjunctival disorder exhibiting degenerative and hyperplastic changes as well as proliferative, inflammatory features and a rich vasculature. Epidemiological studies indicate chronic exposure to the sun and most probably ultraviolet B light as an important factor in the development of pterygium. Recent report assumes Renin-angiotensin system (RAS) as a new potential mediator for growth factor and an immunomodulator that influences cell proliferation, apoptosis, tissue fibrosis and participates in inflammatory responses. RAS is classically conceived as a coordinated hormonal cascade in the control of cardiovascular, renal, and adrenal functions, mainly through the actions of Angiotensin II (Ang II), moreover novel studies assume RAS may be involved in the inflammatory process. Ang II is not only a potent vasoconstrictor and a stimulant of the aldosterone release, but also a growth factor and an immunomodulator that influences cell proliferation, apoptosis, and tissue fibrosis, and participates in inflammatory responses in a non-hemodynamic manner. Furthermore, the Ang II enhances vascular endothelial growth factor and contributes to the recruitment of inflammatory cells by inducing chemokines and adhesion molecules. Ang II is generated by enzymatic action of Angiotensin Converting Enzyme (ACE I). Besides the action of Ang II, exists an “alternative” way mediated by Angiotensin-(1-7). Angiotensin-(1-7) [Ang-(1-7)] is an alternative metabolite of the RAS system with actions in opposition to those of Ang II. It is generated by enzymatic action of Angiotensin Converting Enzyme II (ACE II). These evidences may suggest the RAS system such as a double antagonist model: a vasoconstrictor/proliferative role in which the major player is Ang II; and a vasodilator/anti-proliferative role in which the major effector is Ang-(17). Due to the relationship among UVB damage, molecular mechanisms of conjunctival cells alterations and pterygium features, ACE I and ACE II were immunohistochemically examined to investigate the possible overexpression, and their relationship, in primary pterygium. The results will be discussed.