Homeobox genes are transcription factors primarily involved in embryonic development. Several homeobox gene families have so far been identi®ed: Hox, EMX, PAX, MSX as well as many isolated divergent homeobox genes. Among these, Hox genes are most intriguing for having a regulatory network structure organization. Recent indications suggest the involvement of homeobox genes in (i) crucial adult eukariotic cell functions and (ii) human diseases, spanning from diabetes to cancer. In this review we will discuss the mechanisms through which homeobox genes act, and will propose a model for the function of the Hox gene network as decoding system for achieving speci®c genetic programs. New technologies for whole-genome RNA expression will be crucial to evaluate the clinical relevance of homeobox genes in structural and metabolic diseases.

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Growing evidence indicates that adiposity is associated with raised cancer incidence, morbidity and mortality. In a subset of tumors, cancer cell growth and/or metastasis predominantly occur in adipocyte-rich microenvironment. Indeed, adipocytes represent the most abundant cell types surrounding breast cancer cells. We have studied the mechanisms by which peritumoral human adipose tissue contributes to Triple Negative Breast Cancer (TNBC) cell invasiveness and dissemination.Co-culture with human adipocytes enhanced MDA-MB231 cancer cell invasiveness. Adipocytes cultured in high glucose were 2-fold more active in promoting cell invasion and motility compared to those cultured in low glucose. This effect is induced, at least in part, by the CC-chemokine ligand 5 (CCL5). Indeed, CCL5 inhibition by specific peptides and antibodies reduced adipocyte-induced breast cancer cell migration and invasion. CCL5 immuno-detection in peritumoral adipose tissue of women with TNBC correlated with lymph node (p-value = 0.04) and distant metastases (p-value = 0.001). A positive trend was also observed between CCL5 expression and glycaemia. Finally, Kaplan-Meier curves showed a negative correlation between CCL5 staining in the peritumoral adipose tissue and overall survival of patients (p-value = 0.039).Thus, inhibition of CCL5 in adipose microenvironment may represent a novel approach for the therapy of highly malignant TNBC.

While the overall mortality for breast cancer has recently declined, management of triple-negative breast cancer (TNBC) is still challenging because of its aggressive clinical behavior and the lack of targeted therapies. Genomic profiling studies highlighted the high level of heterogeneity of this cancer, which comprises different subtypes with unique phenotypes and response to treatment. Platelet-derived growth factor receptor β (PDGFRβ) is an established mesenchymal/stem cell-specific marker in human glioblastoma and, as recently suggested, it may uniquely mark breast cancer cells with stem-like characteristics and/or that have undergone epithelial-mesenchymal transition.Methods: Immunohistochemical analysis for PDGFRβ expression was performed on a human TNBC tissue microarray. Functional assays were conducted on mesenchymal-like TNBC cells to investigate the effect of a previously validated PDGFRβ aptamer on invasive cell growth in three-dimensional culture conditions, migration, invasion and tube formation. The aptamer was labeled with a near-infrared (NIR) dye and its binding specificity to PDGFRβ was assessed both in vitro (confocal microscopy and flow cytometry analyses) and in vivo (fluorescence molecular tomography in mice bearing TNBC xenografts). A mouse model of TNBC lung metastases formation was established and NIR-labeled PDGFRβ aptamer was used to detect lung metastases in mice untreated or intravenously injected with unlabeled aptamer.Results: Here, we present novel data showing that tumor cell expression of PDGFRβ identifies a subgroup of mesenchymal tumors with invasive and stem-like phenotype, and propose a previously unappreciated role for PDGFRβ in driving TNBC cell invasiveness and metastases formation. We show that the PDGFRβ aptamer blocked invasive growth and migration/invasion of mesenchymal TNBC cell lines and prevented TNBC lung metastases formation. Further, upon NIR-labeling, the aptamer specifically bound to TNBC xenografts and detected lung metastases.Conclusions: We propose PDGFRβ as a reliable biomarker of a subgroup of mesenchymal TNBCs with invasive and stem-like phenotype as well as the use of the PDGFRβ aptamer as a high efficacious tool for imaging and suppression of TNBC lung metastases. This study will allow for the significant expansion of the current repertoire of strategies for managing patients with more aggressive TNBC.

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Adipogenesis is regulated by the sequential activation of a series of transcription factors: the C/EBP proteins of type beta and delta trigger the process while PPARgamma and C/EBPalpha induce the differentiation from pre-adipocyte to adipocyte, followed by adipo-specific gene expression. A number of observations suggest the involvement of genes controlling embryonal development in adipogenesis. In human thyroid follicular carcinoma, it has been recently identified an oncogenetic fusion protein resulting from the interaction between the isoform PPARgamma1 of PPARgamma and the homeoprotein encoded by the PAX-8 gene. Recent observations have pointed out that gene expression associated with adipocyte differentiation in vivo and in vitro, although partially overlapping, is actually different. HOX genes make up a network of transcription factors (homeoproteins) controlling embryonal development as well as crucial functions of adult eukaryotic cells. The molecular organization of this network of 39 genes appears to be unique in the genome and probably acts regulating phenotypic cell identity. In the present study we have analyzed the expression of the complete HOX gene network, in vivo, in different deposits of human white adipose tissue and in embryonal brown adipose tissues. Most of the genes in the HOX network are active in white as well as brown adipose tissue. Furthermore HOX genes display a deposit-specific expression in white adipose tissue. Moreover, expression of the paralogous group 4 genes (HOX A4, HOX B4, HOX C4, and HOX D4), together with that of isolated genes in the network, appears to discriminate between white and brown adipose tissue. This data allows us to postulate the involvement of the HOX network in transcriptional regulation of human adipogenesis and to hypothesize on the molecular mechanisms that could be implicated.

Background:Several evidences suggest a marked angiogenic dependency in triple-negative breast cancer (TNBC) tumorigenesis and a potential sensitivity to anti-angiogenic agents. Herein, the putative role of Hedgehog (Hh) pathway in regulating TNBC-dependent angiogenesis was investigated.Methods:Expression and regulation of the Hh pathway transcription factor glioma-associated oncogene homolog1 protein (GLI1) were studied on the endothelial compartment and on TNBC-initiated angiogenesis. To evaluate the translational relevance of our findings, the combination of paclitaxel with the Smo inhibitor NVP-LDE225 was tested in TNBC xenografted mice.Results:Tissue microarray analysis on 200 TNBC patients showed GLI1 overexpression paired with vascular endothelial growth factor receptor 2 (VEGFR2) expression. In vitro, Hh pathway promotes TNBC progression in an autocrine manner, regulating the VEGF/VEGFR2 loop on cancer cell surface, and in a paracrine manner, orchestrating tumour vascularisation. These effects were counteracted by Smo pharmacological inhibition. In TNBC xenografted mice, scheduling NVP-LDE225 rather than bevacizumab provided a better sustained inhibition of TNBC cells proliferation and endothelial cells organisation.Conclusions:This study identifies the Hh pathway as one of the main regulators of tumour angiogenesis in TNBC, thus suggesting Hh inhibition as a potential new anti-angiogenic therapeutic option to be clinically investigated in GLI1 overexpressing TNBC patients.

BackgroundThe resistance to PD-1/PD-L1 inhibitors for the treatment of melanoma have prompted investigators to implement novel clinical trials which combine immunotherapy with different treatment modalities. Moreover is also important to investigate the mechanisms which regulate the dynamic expression of PD-L1 on tumor cells and PD-1 on T cells in order to identify predictive biomarkers of response. COX-2 is currently investigated as a major player of tumor progression in several type of malignancies including melanoma. In the present study we investigated the potential relationship between COX-2 and PD-L1 expression in melanoma.MethodsTumor samples obtained from primary melanoma lesions and not matched lymph node metastases were analyzed for both PD-L1 and COX-2 expression by IHC analysis. Status of BRAF and NRAS mutations was analyzed by sequencing and PCR. Co-localization of PD-L1 and COX-2 expression was analyzed by double fluorescence staining. Lastly the BRAFV600E A375 and NRASQ61R SK-MEL-2 melanoma cell lines were used to evaluate the effect of COX-2 inhibition by celecoxib on expression of PD-L1 in vitro.ResultsBRAFV600E/V600K and NRASQ61R/Q61L were detected in 57.8 and 8.9% of the metastatic lesions, and in 65.9 and 6.8% of the primary tumors, respectively. PD-L1 and COX-2 expression were heterogeneously expressed in both primary melanoma lesions and not matched lymph node metastases. A significantly lower number of PD-L1 negative lesions was found in primary tumors as compared to not matched metastatic lesions (P = 0.002). COX-2 expression significantly correlated with PD-L1 expression in both primary (P = 0.001) and not matched metastatic (P = 0.048) lesions. Furthermore, in melanoma tumors, cancer cells expressing a higher levels of COX-2 also co-expressed a higher level of PD-L1. Lastly, inhibition of COX-2 activity by celecoxib down-regulated the expression of PD-L1 in both BRAFV600E A375 and NRASQ61R SK-MEL-2 melanoma cell lines.ConclusionsCOX-2 expression correlates with and modulates PD-L1 expression in melanoma cells. These findings have clinical relevance since they provide a rationale to implement novel clinical trials to test COX-2 inhibition as a potential treatment to prevent melanoma progression and immune evasion as well as to enhance the anti-tumor activity of PD-1/PD-L1 based immunotherapy for the treatment of melanoma patients with or without BRAF/NRAS mutations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-017-1150-7) contains supplementary material, which is available to authorized users.