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Mar del Plata, Argentina

Santini R.,Core Research Laboratory Istituto Toscano Tumori | Vinci M.C.,Core Research Laboratory Istituto Toscano Tumori | Pandolfi S.,Core Research Laboratory Istituto Toscano Tumori | Penachioni J.Y.,Core Research Laboratory Istituto Toscano Tumori | And 7 more authors.
Stem Cells

The question of whether cancer stem/tumor-initiating cells (CSC/TIC) exist in human melanomas has arisen in the last few years. Here, we have used nonadherent spheres and the aldehyde dehydrogenase (ALDH) enzymatic activity to enrich for CSC/TIC in a collection of human melanomas obtained from a broad spectrum of sites and stages. We find that melanomaspheres display extensive in vitro self-renewal ability and sustain tumor growth in vivo, generating human melanoma xenografts that recapitulate the phenotypic composition of the parental tumor. Melanomaspheres express high levels of Hedgehog (HH) pathway components and of embryonic pluripotent stem cell factors SOX2, NANOG, OCT4, and KLF4. We show that human melanomas contain a subset of cells expressing high ALDH activity (ALDHhigh), which is endowed with higher self-renewal and tumorigenic abilities than the ALDHlow population. A good correlation between the number of ALDHhigh cells and sphere formation efficiency was observed. Notably, both pharmacological inhibition of HH signaling by the SMOOTHENED (SMO) antagonist cyclopamine and GLI antagonist GANT61 and stable expression of shRNA targeting either SMO or GLI1 result in a significant decrease in melanoma stem cell self-renewal in vitro and a reduction in the number of ALDHhigh melanoma stem cells. Finally, we show that interference with the HH-GLI pathway through lentiviral-mediated silencing of SMO and GLI1 drastically diminishes tumor initiation of ALDHhigh melanoma stem cells. In conclusion, our data indicate an essential role of the HH-GLI1 signaling in controlling self-renewal and tumor initiation of melanoma CSC/TIC. Targeting HH-GLI1 is thus predicted to reduce the melanoma stem cell compartment. © AlphaMed Press. Source

Valencia K.,University of Navarra | Luis-Ravelo D.,University of Navarra | Bovy N.,University of Liege | Anton I.,University of Navarra | And 11 more authors.
Molecular Oncology

Bone metastasis represents one of the most deleterious clinical consequences arising in the context of many solid tumors. Severe osteolysis results from tumor cell colonization of the bone compartment, a process which entails reciprocal exchange of soluble signals between tumor cells and their osseous microenvironment. Recent evidence indicates that tumor-intrinsic miRNAs are pleiotropic regulators of gene expression. But they are also frequently released in exosome-like vesicles (ELV). Yet the functional relevance of the transference of tumor-derived ELV and their miRNA cargo to the extracellular milieu during osseous colonization is unknown.Comparative transcriptomic profiling using an invivo murine model of bone metastasis identified a repressed miRNA signature associated with high prometastatic activity. Forced expression of single miRNAs identified miR-192 that markedly appeased osseous metastasis invivo, as shown by X-ray, bioluminescence imaging and microCT scans. Histological examination of metastatic lesions revealed impaired tumor-induced angiogenesis invivo, an effect that was associated invitro with decreased hallmarks of angiogenesis. Isolation and characterization of ELV by flow cytometry, Western blot analysis, transmission electron microscopy and nanoparticle tracking analysis revealed the ELV cargo enrichment in miR-192. Consistent with these findings, fluorescent labeled miR-192-enriched-ELV showed the invitro transfer and release of miR-192 in target endothelial cells and abrogation of the angiogenic program by repression of proangiogenic IL-8, ICAM and CXCL1. © 2014 Federation of European Biochemical Societies. Source

Abdullgaffar B.,Dubai Hospital | Alsaleh J.,Rheumatology Unit | Hattawi H.,Immunology Unit
Diagnostic Cytopathology

To compare the frequency of abnormal cervical cytology in women with systemic lupus erythematosus (SLE) with that of healthy women without connective tissue diseases by using ThinPrep™ liquid based Pap Tests TM. A retrospective case-control study over 2 years was conducted. The cases included all women with SLE who had Pap tests during their treatment period. The control group included all women without SLE or other connective tissue diseases (CTDs) that had routine Pap tests in the same period. The age and demographic features were adjusted and matched for both groups. Statistical analysis included Chi-Square test and Fischer exact test. The SLE group (n= 55) showed significantly (P < 0.05) more abnormal cervical squamous epithelial abnormalities [14 positive cases (25.4%) than the controls (n = 8,175, with 285 positive cases (3.5%)]. Women with SLE had statistically significant higher frequency and prevalence of squamous intraepithelial lesions than women without SLE of similar age and demographic background. The data suggested that women with SLE might benefit from more frequent cervical cytology screening. Diagn. Cytopathol. 2010. © 2010 Wiley-Liss, Inc. Source

Pandolfi S.,Core Research Laboratory Istituto Toscano Tumori | Montagnani V.,Core Research Laboratory Istituto Toscano Tumori | Penachioni J.Y.,Core Research Laboratory Istituto Toscano Tumori | Vinci M.C.,Core Research Laboratory Istituto Toscano Tumori | And 3 more authors.

The Hedgehog-GLI (HH-GLI) signaling plays a critical role in controlling growth and tissue patterning during embryogenesis and is implicated in a variety of human malignancies, including those of the skin. Phosphorylation events have been shown to regulate the activity of the GLI transcription factors, the final effectors of the HH-GLI signaling pathway. Here, we show that WIP1 (or PPM1D), an oncogenic phosphatase amplified/overexpressed in several types of human cancer, is a positive modulator of the HH signaling. Mechanistically, WIP1 enhances the function of GLI1 by increasing its transcriptional activity, nuclear localization and protein stability, but not of GLI2 nor GLI3. We also find that WIP1 and GLI1 are in a complex. Modulation of the transcriptional activity of GLI1 by WIP1 depends on the latter's phosphatase activity and, remarkably, does not require p53, a known WIP1 target. Functionally, we find that WIP1 is required for melanoma and breast cancer cell proliferation and self-renewal in vitro and melanoma xenograft growth induced by activation of the HH signaling. Pharmacological blockade of the HH pathway with the SMOOTHENED antagonist cyclopamine acts synergistically with inhibition of WIP1 in reducing growth of melanoma and breast cancer cells in vitro. Overall, our data uncover a role for WIP1 in modulating the activity of GLI1 and in sustaining cancer cell growth and cancer stem cell self-renewal induced by activation of the HH pathway. These findings open a novel therapeutic approach for human melanomas and, possibly, other cancer types expressing WIP1 and with activated HH pathway. © 2013 Macmillan Publishers Limited All rights reserved 0950-9232/13. Source

Valencia K.,University of Navarra | Martin-Fernandez M.,Institute Investigacion Sanitaria Fundacion Jimenez Diaz | Zandueta C.,University of Navarra | Ormazabal C.,University of Navarra | And 5 more authors.

Recent evidence suggests that miRNAs could be used as serum markers in a variety of normal and pathological conditions. In this study, we aimed to identify novel miRNAs associated with skeletal metastatic disease in a preclinical model of lung cancer bone metastasis. We assessed the validity of these miRNAs as reliable serum biochemical markers to monitor the extent of disease and response to treatment in comparison to imaging techniques and standard biochemical markers of bone turnover. Using a murine model of human lung cancer bone metastasis after zoledronic acid (ZA) treatment, PINP (procollagen I amino-terminal propeptide) was the only marker that exhibited a strong correlation with osteolytic lesions and tumor burden at early and late stages of bone colonization. In contrast, BGP (osteocalcin) and CTX (carboxyterminal telopeptide) demonstrated a strong correlation only at late stages. We performed qPCR based screening of a panel of 380 human miRNAs and quantified bone metastatic burden using micro-CT scans, X-rays and bioluminescence imaging. Interestingly, levels of miR-326 strongly associated with tumor burden and PINP in vehicle-treated animals, whereas no association was found in ZA-treated animals. Only miR-193 was associated with biochemical markers PINP, BGP and CTX in ZA-treated animals. Consistently, miR-326 and PINP demonstrated a strong correlation with tumor burden. Our findings, taken together, indicate that miR-326 could potentially serve as a novel biochemical marker for monitoring bone metastatic progression. © 2012 Elsevier Inc. Source

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