Melanoma is a highly aggressive tumour that can metastasize very early in disease progression. Notably, melanoma can disseminate using amoeboid invasive strategies. We show here that high Myosin II activity, high levels of ki-67 and high tumour-initiating abilities are characteristic of invasive amoeboid melanoma cells. Mechanistically, we find that WNT11-FZD7-DAAM1 activates Rho-ROCK1/2-Myosin II and plays a crucial role in regulating tumour-initiating potential, local invasion and distant metastasis formation. Importantly, amoeboid melanoma cells express both proliferative and invasive gene signatures. As such, invasive fronts of human and mouse melanomas are enriched in amoeboid cells that are also ki-67 positive. This pattern is further enhanced in metastatic lesions. We propose eradication of amoeboid melanoma cells after surgical removal as a therapeutic strategy.

BackgroundIdiopathic pulmonary fibrosis (IPF) is a progressive parenchymal lung disease of unknown aetiology and poor prognosis, characterized by altered tissue repair and fibrosis. The extracellular matrix (ECM) is a critical component in regulating cellular homeostasis and appropriate wound healing. The aim of our study was to determine the expression profile of highlighted ECM proteins in IPF lungs.MethodsECM gene and protein expression was analyzed by cDNA microarrays, rt-PCR, immunohistochemistry and western-blot in lungs from idiopathic pulmonary fibrosis (IPF), hypersensitivity pneumonitis (HP), categorized as chronic (cHP) and subacute (saHP), and healthy lung tissue. Primary fibroblast cultures from normal subjects and fibrotic patients were studied to evaluate tenascin-C (TNC) synthesis.ResultsA total of 20 ECM proteins were upregulated and 6 proteins downregulated in IPF. TNC was almost undetected in normal lungs and significantly upregulated in fibrotic lungs (IPF and cHP) compared to saHP. Furthermore, it was located specifically in the fibroblastic foci areas of the fibrotic lung with a subepithelial gradient pattern. TNC levels were correlated with fibroblastic foci content in cHP lungs. Versican and fibronectin glycoproteins were associated with TNC, mainly in fibroblastic foci of fibrotic lungs. Fibroblasts from IPF patients constitutively synthesized higher levels of TNC than normal fibroblasts. TNC and α-sma was induced by TGF-β1 in both fibrotic and normal fibroblasts. TNC treatment of normal and fibrotic fibroblasts induced a non-significant increased α-sma mRNA.ConclusionsThe difference in ECM glycoprotein content in interstitial lung diseases could contribute to the development of lung fibrosis. The increase of TNC in interstitial areas of fibrotic activity could play a key role in the altered wound healing.

Epidermal keratinocytes and hair follicle (HF) stem cells (SCs) expressing oncogenes are competent at developing squamous cell carcinomas (SCCs) in epidermis and HFs, respectively. To determine whether bulge and hair germ (HG) SCs from HF contribute to SCC generation at distant epidermis, the most frequent epidermal region where these lesions arise in human skin, we used a skin cancer mouse model expressing E6 and E7 oncoproteins from Human papillomavirus (HPV) 16 in SCs and basal keratinocytes. This previously described mouse model recapitulates the human skin papillomavirus-induced SCC pathology. We show that E6 and E7 expression promote the expansion of keratin 15 (K15)-expressing cells. These K15(+) aberrant cells exhibit some HGSC markers and diminished expression of Tcf3 and Sox9 hair SC specification genes, which are accumulated in HFs and mislocalized to interfollicular epidermis. Leucine-rich G-protein-coupled receptor 5 (Lgr5)-expressing SCs, localized in the bulge and HG, are the origin of the expanded K15(+) cell population. A large subset of the Lgr5(+) SC progeny, expressing K15 and P-cadherin, is aberrantly mobilized to the upper region of HFs and the epidermis, and accumulates at E6/E7-induced pre-neoplastic lesions and epidermal tumors. These findings indicate that aberrant accumulation of altered SCs in HFs and their subsequent migration to the epidermis contribute to HPV-induced tumor development.

Little is known about the molecular events occurring in the metastases of human tumours. Epigenetic alterations are dynamic lesions that change over the natural course of the disease, and so they might play a role in the biology of cancer cells that have departed from the primary tumour. Herein, we have adopted an epigenomic approach to identify some of these changes. Using a DNA methylation microarray platform to compare paired primary tumour and lymph node metastatic cell lines from the same patient, we observed cadherin-11 promoter CpG island hypermethylation as a likely target of the process. We found that CDH11 DNA methylation-associated transcriptional silencing occurred in the corresponding lymph node metastases of melanoma and head and neck cancer cells but not in the primary tumours. Using in vitro and in vivo cellular and mouse models for depleted or enhanced CDH11 activity, we also demonstrated that CDH11 acts as an inhibitor of tumour growth, motility and dissemination. Most importantly, the study of CDH11 5′-CpG island hypermethylation in primary tumours and lymph node metastases of cancer patients showed this epigenetic alteration to be significantly confined to the disseminated cells. Overall, these results indicate the existence of metastasis-specific epigenetic events that might contribute to the progression of the disease. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Hemorrhagic hereditary telangiectasia (HHT) type 2 patients have increased activation of the phosphatidylinositol 3-kinase (PI3K) signaling pathway in telangiectasia. The main objective is to evaluate the activation of the PI3K pathway in cutaneous telangiectasia of HHT1 patients. A cutaneous biopsy of a digital hand telangiectasia was performed in seven HHT1 and eight HHT2 patients and compared with six controls. The study was approved by the Clinical Research Ethics Committee of our center. A histopathological pattern with more dilated and superficial vessels that pushed up the epidermis was identified in HHT patients regardless of the type of mutation and was associated with older age, as opposed to the common telangiectasia pattern. The mean proliferation index (Ki-67) was statistically higher in endothelial cells (EC) from HHT1 than in controls. The percentage of positive EC for pNDRG1, pAKT, and pS6 in HHT1 patients versus controls resulted in higher values, statistically significant for pNDRG1 and pS6. In conclusion, we detected an increase in EC proliferation linked to overactivation of the PI3K pathway in cutaneous telangiectasia biopsies from HHT1 patients. Our results suggest that PI3K inhibitors could be used as novel therapeutic agents for HHT.

BackgroundHuman papillomavirus (HPV) is the cause of a fraction of head and neck squamous cell carcinoma. Although this relation is well-known, it is still not clear the role of HPV in premalignant oral lesions such as oral lichen planus (OLP) and dysplasia. We aimed to evaluate the HPV-DNA prevalence and type distribution in a set of oral biopsies obtained from patients diagnosed with OLP and dysplasia, as well as the role of HPV in these lesions.MethodsA retrospective cohort of all premalignant oral lesions consecutively diagnosed from March 30th 1995 to May 21st 2014 at Hospital of Bellvitge and Odontological University Hospital of Bellvitge was identified and classified in four groups: OLP (groups 1 and 2) and dysplasias (groups 3 and 4) that progressed or not to invasive cancer during follow-up. A random selection targeting 25 cases was aimed to be performed for each group. All selected cases were subjected to pathological evaluation, DNA quality control and HPV-DNA detection. HPV-DNA positive samples were further subject to p16INK4a analysis.ResultsA total of 83 cases yielded a valid HPV-DNA result. From those, 7 and 34 cases were OLP that progressed or not to invasive cancer during follow-up, whereas 24 and 18 cases were displasias that progressed or not to invasive cancer during follow-up, respectively. HPV-DNA was detected in 4 samples (3 dysplastic lesions and 1 OLP). Two samples were HPV16 positive (2%), 1 sample HPV18 positive (1%) and 1 sample (1%) was HPV indeterminate. Two out of four HPV-DNA positive cases had high p16INK4a expression and none of the HPV positive cases progressed to invasive cancer during long-term follow-up.ConclusionsWe found a low HPV-DNA attributable fraction in premalignant lesions of the oral cavity, suggesting that HPV is unlikely to play a significant role in oral carcinogenesis in our setting.

Advanced and undifferentiated skin squamous cell carcinomas (SCCs) exhibit aggressive growth and enhanced metastasis capability, which is associated in mice with an expansion of the cancer stem-like cell (CSC) population and with changes in the regulatory mechanisms that control the proliferation and invasion of these cells. Indeed, autocrine activation of PDGFRα induces CSC invasion and promotes distant metastasis in advanced SCCs. However, the mechanisms involved in this process were unclear. Here, we show that CSCs of mouse advanced SCCs (L-CSCs) express CXCR4 and CXCR7, both receptors of SDF-1. PDGFRα signaling induces SDF-1 expression and secretion, and the autocrine activation of this pathway in L-CSCs. Autocrine SDF-1/CXCR4 signaling induces L-CSC proliferation and survival, and mediates PDGFRα-induced invasion, promoting in vivo lung metastasis. Validation of these findings in patient samples of skin SCCs shows a strong correlation between the expression of SDF1, PDGFRA, and PDGFRB, which is upregulated, along CXCR4 in tumor cells of advanced SCCs. Furthermore, PDGFR regulates SDF-1 expression and inhibition of SDF-1/CXCR4 and PDGFR pathways blocks distant metastasis of human PD/S-SCCs. Our results indicate that functional crosstalk between PDGFR/SDF-1 signaling regulates tumor cell invasion and metastasis in human and mouse advanced SCCs, and suggest that CXCR4 and/or PDGFR inhibitors could be used to block metastasis of these aggressive tumors.

Cancer stem-like cells (CSC) play key roles in long-term tumor propagation and metastasis, but their dynamics during disease progression are not understood. Tumor relapse in patients with initially excised skin squamous cell carcinomas (SCC) is characterized by increased metastatic potential, and SCC progression is associated with an expansion of CSC. Here, we used genetically and chemically-induced mouse models of skin SCC to investigate the signaling pathways contributing to CSC function during disease progression. We found that CSC regulatory mechanisms change in advanced SCC, correlating with aggressive tumor growth and enhanced metastasis. b-Catenin and EGFR signaling, induced in early SCC CSC, were downregulated in advanced SCC. Instead, autocrine FGFR1 and PDGFRa signaling, which have not been previously associated with skin SCC CSC, were upregulated in late CSC and promoted tumor growth and metastasis, respectively. Finally, high-grade and recurrent human skin SCC recapitulated the signaling changes observed in advanced mouse SCC. Collectively, our findings suggest a stage-specific switch in CSC regulation during disease progression that could be therapeutically exploited by targeting the PDGFR and FGFR1 pathways to block relapse and metastasis of advanced human skin SCC.