Salvatore Travali

The tumor microenvironment in hepatocellular carcinoma (review).

The tumor microenvironment has been largely studied as a dynamic system orchestrated by inflammatory cells, including cancer cells, stroma as well as the extracellular matrix. It is useful to describe and predict the phenotypic characteristics of cancer. Furthermore, a better understanding of its interplay with the various aspects of the tumor cells may be utilized for the discovery of novel molecular targets. Liver cancer is considered a model of the relation occurring between the tumor micro-environment and tumor development. The chronic inflammatory status of the liver, sustained by the infection of hepatitis viruses, as well as the production of cytokines and growth factors within the parenchyma, lead to an intricate microenvironment. The identification of novel molecular therapeutic targets may improve the outcome of patients with liver cancer as it remains the third leading cause of cancer death worldwide. In the present study, the tumor microenvironment in hepatocellular carcinoma (HCC) was explored by a review of the literature. Studies on hepatitis virus infections and the consequent chronic inflammatory status were examined. In this context, immune-mediated and/or virus-related molecular mechanisms have been hypothesized as being responsible for liver cancer development. The interlink among HCC microenvironment components, comprising cellular elements, cytokines, growth factors and several proteins is also described together with the role of matrix metalloproteinases in HCC development. Finally, the rationale for targeting tumor-stromal interface is summarized in the context of new therapeutic opportunities.

Gene alterations in the PI3K/PTEN/AKT pathway as a mechanism of drug-resistance (Review)

The most common therapeutic approach for many cancers is chemotherapy. However, many patients relapse after treatment due to the development of chemoresistance. Recently, targeted therapies represent novel approaches to destroy cancer cells. The PI3K/PTEN/AKT pathway is a key signaling pathway involved in the regulation of cell growth. Dysregulated signaling of this pathway may be associated with activating mutations of PI3K-related genes. Analyses of these mutations reveal that they increase the PI3K signal, stimulate downstream Akt signaling, promote growth factor-independent growth and increase cell invasion and metastasis. In this review, we summarize the PI3K/PTEN/AKT pathway genetic alterations in cancer and their potential clinical applications.

Analysis of BRAF mutation in primary and metastatic melanoma.

Mutation of BRAF has been proposed to contribute to melanoma development. However, it remains unclear whether or not BRAF mutation is associated with any particular stage of melanoma progression. Tumor biopsy specimens from patients with melanoma were analyzed to determine whether the frequency of BRAF mutation in metastatic melanoma differed from primary melanoma. BRAF mutation was present in 15 of 23 (61%) patients with primary melanoma and in 7 of 12 (58%) patients with metastatic melanoma. These results suggest that BRAF mutation in melanoma is most likely to occur prior to the development of metastatic disease.

Activation of the Osteopontin/Matrix Metalloproteinase-9 Pathway Correlates with Prostate Cancer Progression

Purpose: Prostate cancer remains the second most frequent cause of tumor-related deaths in the Western world. Additional markers for the identification of prostate cancer development and progression are needed. Osteopontin (OPN), which activates matrix metalloproteinases (MMP), is considered a prognostic biomarker in several cancers. “In silico” and experimental approaches were used to determine whether OPN-mediated MMP activation may be a signal of prostate cancer progression. Experimental Design: Pearson correlation coefficients were computed for each OPN/MMP pair across seven publicly available prostate cancer gene expression data sets. Using Gene Set Enrichment Analysis, 101 cancer-related gene sets were analyzed for association with OPN and MMP-9 expression. OPN, MMP-9, MMP-2 tissue inhibitor of metalloproteinase-1 plasma levels, and MMP gelatinase activity were measured by ELISA and zymography in 96 and 92 patients with prostate cancer and benign prostatic hyperplasia, respectively, and 125 age-matched healthy men. Results: Computational analyses identified a significant correlation only between MMP-9 and OPN, and showed significant enrichment scores in “cell proliferation”, “genes constituting the phosphoinositide-3-kinase predictor”, “proliferation signature”, and “tumor metastasis” gene sets in association with both OPN and MMP-9. Plasma analyses revealed a significant increase in OPN and MMP-9 levels and activity in patients with prostate cancer in association with clinical variables (prostate-specific antigen >4 ng/mL and Gleason score >7). Significant correlation between OPN and MMP-9 levels were also observed. Mean plasma levels of OPN and MMP-9 decreased in patients with prostate cancer within 6 months after prostatectomy. Conclusions: The concordant computational and experimental data indicate that the extent of OPN pathway activation correlates with prostate cancer progression.

Tissue‐specific and Developmental Expression of Pituitary Adenylate Cyclase‐activating Polypeptide (PACAP) Receptors in Rat Brain

The two forms of pituitary adenylate cyclase‐activating polypeptide, PACAP27 and PACAP38, are novel members of the vasoactive intestinal peptide (VIP)/secretin/glucagon family of peptides. PACAP receptors that are positively coupled to adenylate cyclase and phospholipase C have been recently identified. We examined the expression of PACAP receptors in the rat cortex, hippocampus, cerebellum and hypothalamus during postnatal development. Functional studies revealed PACAP stimulation of cAMP formation in all the brain areas examined and [3H]inositol monophosphate ([3H]insP) accumulation only in the cerebellum and hypothalamus. Throughout development, the efficacy of PACAP in stimulating cAMP formation slightly increased in the cortex and hypothalamus and decreased in the hippocampus and cerebellum; PACAP stimulation of [3H]lnsP formation decreased in the cerebellum and remained steady in the hypothalamus. The effects of PACAP27 and PACAP38 on cAMP levels and inositol phospholipid hydrolysis were dose‐dependent between 1 and 100 nM. In the same brain areas, treatment with VIP increased cAMP formation at doses greater than 100 nM and failed to affect [3H]lnsP content, thus suggesting the existence of type‐l PACAP receptors. The reverse transcription polymerase chain reaction (RT‐PCR) was used to analyse the mRNA expression of type‐l PACAP receptor splice variants. PACAP receptor gene expression in the central nervous system was regulated in a developmental‐ and tissue‐specific manner. The PACAP‐R transcript was detected in all the brain areas examined whereas PACAP‐R‐hop mRNA occurred only in the cerebellum and hypothalamus. The different expression profiles and functional properties of PACAP receptors in the developing rat brain suggest an involvement of PACAP in histogenesis, maturation and neurotransmission.

Yin Yang 1 overexpression in diffuse large B-cell lymphoma is associated with B-cell transformation and tumor progression

Yin Yang 1 (YY1), a multifunctional transcription factor, has been shown to be involved in the pathogenesis of several cancer types. However, its role in hematological malignancies has not yet been fully investigated. In the present study, using computational methods, we showed that YY1 transcript levels were significantly increased in the high-grade lymphomas, including Burkitt’s lymphoma and diffuse large B-cell lymphoma (DLBCL), compared with those of both low-grade lymphomas and normal B-cells. The significant increase in gene expression resulted in a significant increase also at protein level in three NHL cell lines. The association of YY1 expression with some clinical-pathological features in DLBCL showed a positive correlation between a high level of YY1 mRNA and high levels of BCL-6 protein. Moreover, by analyzing the large series of DLBCL in the Hummel dataset, we identified the transcription factor PAX-5 among the top 50 genes positively correlated with YY1. These findings are also supported by the biological network analysis in which the top network, with the highest score, associated with YY1 expression levels in DLBCL is cellular movement, hematological system development and function, and immune response. Overall these data suggest that YY1 is involved in B cells transformation which gives rise to high-grade lymphomas through a dysregulation in the normal development of B cells affecting cell cycle and cellular motility.

Liver is not the unique site of synthesis of β2-glycoprotein I (apolipoprotein H) : evidence for an intestinal localization

Apolipoprotein H is a protein of about 50 kilodaltons, structurally related to the regulators of the complement activation family. Its physiological function is poorly understood but it has been implicated in lipid metabolism and coagulative pathways. The major site of synthesis is thought to be the liver. Several reports indicate that apolipoprotein H is the antigen of the antiphospholipid antibodies and also behaves as an acute-phase reactant. Moreover, 40% of plasma apolipoprotein H is associated with very low-density lipoprotein, high-density lipoprotein, and postprandial chylomicrons. In this study we investigated other sites of synthesis by reverse transcription/polymerase chain reaction and we found apolipoprotein H mRNA expression in intestinal cell lines and tissues. Immunohistochemistry was performed on various fresh and paraffin-embedded tissues and apolipoprotein H was immunolocalized in the cytoplasm of hepatocytes and epithelial cells from colon and jejunum. This study indicates that apolipoprotein H is expressed at both mRNA and protein levels in enterocytes.

Detection of BRAF Gene Mutation in Primary Choroidal Melanoma Tissue

Numerous BRAF mutations have been detected in melanoma biopsy specimens and cell lines. In contrast, several studies report lack of BRAF mutations in uveal melanoma including primary and metastatic choroidal and ciliary body melanomas. To our knowledge, for the first time, here we report a case of choroidal melanoma harboring the BRAF mutation (V600E). The activation of RAF/MEK/ERK pathway, although independent of BRAF mutation, was reported in uveal melanoma. The presence of V600E mutation indicates that the RAF/MEK/ERK pathway, in addition to cutaneous melanoma progression, may play a role in the choroidal melanoma development.

Myofibroblasts of palmar fibromatosis co-express transforming growth factor-alpha and epidermal growth factor receptor.

Several studies have shown that different growth factors are involved in the pathogenesis of palmar fibromatosis. The aim of the present study was to investigate whether transforming growth factor alpha (TGF‐α) and its cellular receptor, epidermal growth factor receptor (EGF‐R), are expressed in palmar fibromatosis. Nodules from 20 patients with palmar fibromatosis and control normal palmar fascias were studied by the reverse transcription‐polymerase chain reaction (RT‐PCR) and immunohistochemistry. RT‐PCR followed by Southern blotting demonstrated that palmar fibromatosis nodules contained high levels of TGF‐α and EGF‐R messenger RNA (mRNA) transcripts, while normal fascias showed only low levels. Depending on the degree of cellularity and fibrosis, the three following histological phases were recognized in palmar fibromatosis nodules: proliferative, involutional, and residual. Immunohistochemistry, using α‐smooth muscle actin as a cellular marker for myofibroblasts, revealed that TGF‐α and EGF‐R are co‐expressed by myofibroblasts in the highly cellular areas of both proliferative and involutional phases, while they are absent or only focally detectable in the fibroblasts of normal fascia and in hypocellular and fibrotic areas of both involutional and residual phases. The restricted co‐expression of TGF‐α and EGF‐R to myofibroblasts, the proliferating cellular component of nodules, suggests that an autocrine and/or juxtacrine growth stimulation by TGF‐α via the EGF‐R may be involved in the pathogenesis of palmar fibromatosis.

Emerging targeted therapies for melanoma treatment (Review)

Cutaneous melanoma is an aggressive cancer with a poor prognosis for patients with advanced disease. The identification of several key molecular pathways implicated in the pathogenesis of melanoma has led to the development of novel therapies for this devastating disease. In melanoma, both the Ras/Raf/MEK/ERK (MAPK) and the PI3K/AKT (AKT) signalling pathways are constitutively activated through multiple mechanisms. Targeting various effectors of these pathways with pharmacologic inhibitors may inhibit melanoma cell growth and angiogenesis. Ongoing clinical trials provide hope to improve progression-free survival of patients with advanced melanoma. This review summarizes the most relevant studies focused on the specific action of these new molecular targeted agents. Mechanisms of resistance to therapy are also discussed.