Novel features of boundary cap cells revealed by the analysis of newly identified molecular markers.

International audienceNeural crest (NC) cells are a multipotent, highly migratory cell population that generates most of the components of the peripheral nervous system (PNS), including the glial Schwann cells (SC) and boundary cap (BC) cells. These latter cells are located at the interface between the central nervous system and PNS, at the exit/entry points of ventral motor/dorsal sensory axons and give rise to all SC in the nerve roots and to a subset of nociceptive neurons and satellite cells in the dorsal root ganglia. In the present study we have compared BC cells with two closely related cell types, NC and Schwann cell precursors (SCpr), by RNA profiling. This led to the definition of a set of 10 genes that show specific expression in BC cells and/or in their derivatives along the nerve roots. Analysis of the expression of these genes during mouse development revealed novel features, of those most important are: (i) dorsal and ventral nerve root BC cell derivatives express different sets of genes, suggesting that they have distinct properties; (ii) these cells undergo major modifications in their gene expression pattern between embryonic days 14.5 and 17.5, possibly linked to the SCpr-immature Schwann cell transition; (iii) nerve roots SC differ from more distal SC not only in their origins and locations, but also in their gene expression patterns. In conclusion, the identification of these novel makers opens the way for a detailed characterization of BC cells in both mouse and man

The value of pretreatment cell kinetic parameters as predictors for radiotherapy outcome in head and neck cancer : a multicenter analysis.

Purpose: The aim of this study was to assess the potential of pre-treatment cell kinetic parameters to predict outcome in head and neck cancer patients treated by conventional radiotherapy. Materials and methods: Data from 11 different centers were pooled. Inclusion criteria were such that the patients received radiotherapy alone, and that the radiotherapy was given in an overall time of at least 6 weeks with a dose of at least 60 Gy. All patients received a tracer dose of either iododeoxyuridine (IdUrd) or bromodeoxyuridine (BrdUrd) intravenously prior to treatment and a tumor biopsy was taken several hours later. The cell kinetic parameters labeling index (LI), DNA synthesis time (Ts) and potential doubling time (Tpot) were subsequently calculated from flow cytometry data, obtained on the biopsies using antibodies against I/BrdUrd incorporated into DNA. Each center carried out their own flow cytometry analysis. Results: From the 11 centers, a total of 476 patients conforming to the inclusion criteria were analyzed. Median values for overall time and total dose were 49 days and 69 Gy, respectively. Fifty one percent of patients had local recurrences and 53% patients had died, the majority from their disease. Median follow-up was 20 months; being 30 months for surviving patients. Multivariate analysis revealed that T-stage, maximum tumor diameter, differentiation grade, N-stage, tumor localization and overall time correlated with locoregional control, in decreasing order of significance. For the cell kinetic parameters, univariate analysis showed that only LI was significantly associated with local control (P=0.02), with higher values correlating with a worse outcome. Ts showed some evidence that patients with longer values did worse, but this was not significant (P=0.06). Tpot showed no trend (P=0.8). When assessing survival in a univariate analysis, neither LI nor Tpot associated with outcome (P=0.4, 0.4, respectively). Surprisingly, Ts did correlate with survival, with longer values being worse (P=0.02). In the multivariate analysis of local control, LI lost its significance (P=0.16). Conclusions: The only pretreatment kinetic parameter for which some evidence was found for an association with local control (the best end-point for testing the present hypothesis) was LI, not Tpot, and this evidence disappeared in a multivariate analysis. It therefore appears that pretreatment cell kinetic measurements carried out using flow cytometry, only provide a relatively weak predictor of outcome after radiotherapy in head and neck cancer.NCI T92-004

Characterization of Breast Cancer Preclinical Models Reveals a Specific Pattern of Macrophage Polarization

<div><p>Drug discovery efforts have focused on the tumor microenvironment in recent years. However, few studies have characterized the stroma component in patient-derived xenografts (PDXs) and genetically engineered mouse models (GEMs). In this study, we characterized the stroma in various models of breast cancer tumors in mice. We performed transcriptomic and flow cytometry analyses on murine populations for a series of 25 PDXs and the two most commonly used GEMs (MMTV-PyMT and MMTV-erBb2). We sorted macrophages from five models. We then profiled gene expression in these cells, which were also subjected to flow cytometry for phenotypic characterization. Hematopoietic cell composition, mostly macrophages and granulocytes, differed between tumors. Macrophages had a specific polarization phenotype related to their M1/M2 classification and associated with the expression of genes involved in the recruitment, invasion and metastasis processes. The heterogeneity of the stroma component of the models studied suggests that tumor cells modify their microenvironment to satisfy their needs. Our observations suggest that such models are of relevance for preclinical studies.</p></div

Histology and immunohistochemistry of myofibroblasts and endothelial cells in human and mouse breast cancer tumors.

<p>Slides stained with hematoxylin, eosin and safranin (HES) and Masson’s trichrome, and stained for α-SMA and CD31: (<b>a</b>) human PDXs and (<b>b</b>) murine PyMT and ErbB2 tumors (original magnification: 400x).</p

M1/M2 macrophage-like cell phenotype in BC tumors.

<p>(<b>a</b>) The expression of genes associated with the M1 (MHC-II, CD86, Cd11c, Il1b, Cxcl10 and Cxcl11) or M2 (Mrc1, Scara4, Scarb3, Arg1, Igf1 and Ccr2) phenotype was assessed by the dissociation of five tumors (MMTV-PyMT, BC-PyMT, HBCx-5, -24 and -34), the sorting of macrophage-like cells, and microarray analysis. Levels of gene expression in BC models were compared in unpaired Student’s <i>t</i>-tests (<b>b</b>) Protein levels for M1 (MHC-II and Cd11c) and M2 (Mrc1) markers on macrophage-like cells from the five tumors MMTV-PyMT, BC-PyMT, HBCx -5, -24 and x-34), as measured by flow cytometry. Three tumors were analyzed per model. For each model, Mann-Whitney tests were performed to compare the results obtained with those for the MMTV-PyMT tumor (* <i>p</i>< 0.05, **<i>p</i> <0.01, ***<i>p</i> <0.001). (<b>c</b>) Examples of flow cytometry findings for the levels of M1 and M2 marker proteins (the corresponding isotype is shown in gray).</p

Transcriptome profiles of macrophage-like cells in BC tumors.

<p>(<b>a</b>) Results of principal component analysis (PCA) for the subset of 1238 genes up- or downregulated in at least one comparison between MMTV-PyMT and BC-PyMT, HBCx-5, -24 or -34. The 15 samples, triplicates of MMTV-PyMT (green), BC-PyMT (orange), HBCx-5 (red), HBCx-24 (yellow) and HBCx-34 (blue), were projected oton the first three principal components, which accounted for ~58% of the total variability. Hierarchical clustering of the genes from the (<b>b</b>) “Immune system process” or (<b>c</b>) “Metabolic process” pathways from Gene Ontology analysis identified as significantly up- or downregulated in at least one comparison between BC-PyMT and HBCx-5, -24 and -34.</p