Anti-IL34 monoclonal antibody, clone 2E23

Background & Aims: A therapeutically challenging subset of cells, termed cancer stem cells (CSCs) are responsible for cholangiocarcinoma (CCA) clinical severity. Presence of tumor associated macrophages (TAMs) has prognostic significance in CCA and other malignancies. Thus, we hypothesized that CSCs may actively shape their tumor-supportive immune niche. Methods: CCA cells were cultured in 3D conditions to generate spheres. CCA sphere analysis of in vivo tumorigenicengraftment in immune-deficient mice and molecular characterization was performed. The in vitro and in vivo effect of CCA spheres on macrophage precursors was tested after culturing healthy donor cluster of differentiation (CD)14(+) with CCA-sphere conditioned medium. Results: CCA spheres engrafted in 100% of transplanted mice and revealed a significant 20.3-fold increase in tumor-initiating fraction (p = 0.0011) and a sustained tumorigenic potential through diverse xenograft-generations. Moreover, CCA spheres were highly enriched for CSC, liver cancer and embryonic stem cell markers both at gene and protein levels. Next, fluorescence activated cell sorting analysis showed that in the presence of CCA sphere conditioned medium, CD14(+) macrophages expressed key markers (CD68, CD115, human leukocyte antigen-D related, CD206) indicating that CCA sphere conditioned medium was a strong macrophage-activator. Gene expression profile of CCA sphere activated macrophages revealed unique molecular TAM-like features confirmed by high invasion capacity. Also, freshly isolated macrophages from CCA resections recapitulated a similar molecular phenotype of in vitro-educated macrophages. Consistent with invasive features, the largest CD163(+) set was found in the tumor front of human CCA specimens (n = 23) and correlated with a high level of serum cancer antigen 19.9 (n = 17). Among mediators released by CCA spheres, only interleukin (IL)13, IL34 and osteoactivin were detected and further confirmed in CCA patient sera (n = 12). Surprisingly, a significant association of IL13, IL34 and osteoactivin with sphere stem-like genes was provided by a CCA database (n = 104). In vitro combination of IL13, IL34, osteoactivin was responsible for macrophage-differentiation and invasion, as well as for in vivo tumor-promoting effect. Conclusion: CCA-CSCs molded a specific subset of stem-like associated macrophages thus providing a rationale for a synergistic therapeutic strategy for CCA-disease. Lay summary: Immune plasticity represents an important hallmark of tumor outcome. Since cancer stem cells are able to manipulate stromal cells to their needs, a better definition of the key dysregulated immune subtypes responsible for cooperating in supporting tumor initiation may facilitate the development of new therapeutic approaches. Considering that human cholangiocarcinoma represents a clinical emergency, it is essential to move to predictive models in order to understand the adaptive process of macrophage component (imprinting, polarization and maintenance) engaged by tumor stem-like compartment. (C) 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Background Colony-stimulating factor 1 (CSF-1) and interleukin (IL)-34 are important for the functions of myeloid lineage cells and are involved in several chronic inflammatory conditions associated with tissue degeneration. The aim of this study is to evaluate the expression of CSF-1 and IL-34 in gingival tissue and gingival fibroblasts (GF) from patients with periodontitis and controls. Methods Gingival biopsies were obtained from 19 periodontitis patients and 15 controls. Expression of CSF-1 and IL-34 in gingival tissue was assessed by western blot and localization by immunohistochemistry. Expression of CSF1 and IL34 mRNA in GF was analyzed by real-time polymerase chain reaction and protein expression visualized by immunofluorescence stainings. CSF-1 and IL-34 secretion from GF was evaluated in response to tumor necrosis factor-alpha (TNF-alpha), IL-1 beta, Escherichia coli lipopolysaccharide (Ec-LPS) and Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) stimulation, using enzyme-linked immunosorbent assays. Results CSF-1 was increased in gingival tissue from periodontitis patients compared with controls (P < 0.05) whereas IL-34 expression was similar. In GF from a non-periodontitis donor, stimulation with either TNF-alpha, IL-1 beta, Ec-LPS, or Pg-LPS, increased the secretion of CSF-1 (P < 0.05) and Ec-LPS stimulation increased IL-34 (P < 0.05). CSF-1 and IL-34 were expressed and secreted constitutively from GF, with comparable levels in GF from periodontitis patients and controls. Inflammatory stimuli increased the secretion of CSF-1 and IL-34 with comparable levels measured from GF from periodontitis patients and controls (P < 0.05). Conclusion The expression of CSF-1 and IL-34 in gingival tissue and fibroblasts suggests involvement in myeloid cell functions during periodontal inflammation.