title: Bone marrow-infiltrating human neuroblastoma cells express high levels of calprotectin and HLA-G proteins.
abstract: Metastases in the bone marrow (BM) are grim prognostic factors in patients with neuroblastoma (NB). In spite of extensive analysis of primary tumor cells from high- and low-risk NB patients, a characterization of freshly isolated BM-infiltrating metastatic NB cells is still lacking. Our aim was to identify proteins specifically expressed by metastatic NB cells, that may be relevant for prognostic and therapeutic purposes. Sixty-six Italian children over 18 months of age, diagnosed with stage 4 NB, were included in the study. Metastatic NB cells were freshly isolated from patients' BM by positive immunomagnetic bead manipulation using anti-GD2 monoclonal antibody. Gene expression profiles were compared with those obtained from archived NB primary tumors from patients with 5 y-follow-up. After validation by RT-qPCR, expression/secretion of the proteins encoded by the up-regulated genes in the BM-infiltrating NB cells was evaluated by flow cytometry and ELISA. Compared to primary tumor cells, BM-infiltrating NB cells down-modulated the expression of CX3CL1, AGT, ATP1A2 mRNAs, whereas they up-regulated several genes commonly expressed by various lineages of BM resident cells. BM-infiltrating NB cells expressed indeed the proteins encoded by the top-ranked genes, S100A8 and A9 (calprotectin), CD177 and CD3, and secreted the CXCL7 chemokine. BM-infiltrating NB cells also expressed CD271 and HLA-G. We have identified proteins specifically expressed by BM-infiltrating NB cells. Among them, calprotectin, a potent inflammatory protein, and HLA-G, endowed with tolerogenic properties facilitating tumor escape from host immune response, may represent novel biomarkers and/or targets for therapeutic intervention in high-risk NB patients.
authors.affiliation: Laboratory of Oncology, Gaslini Institute, Genoa, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Morandi
authors.forename: Paola
authors.initials: P
authors.lastname: Scaruffi
authors.forename: Fabio
authors.initials: F
authors.lastname: Gallo
authors.forename: Sara
authors.initials: S
authors.lastname: Stigliani
authors.forename: Stefano
authors.initials: S
authors.lastname: Moretti
authors.forename: Stefano
authors.initials: S
authors.lastname: Bonassi
authors.forename: Claudio
authors.initials: C
authors.lastname: Gambini
authors.forename: Katia
authors.initials: K
authors.lastname: Mazzocco
authors.forename: Paolo
authors.initials: P
authors.lastname: Fardin
authors.forename: Riccardo
authors.initials: R
authors.lastname: Haupt
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Arcamone
authors.forename: Vito
authors.initials: V
authors.lastname: Pistoia
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Tonini
authors.forename: Maria Valeria
authors.initials: MV
authors.lastname: Corrias
mesh_terms: D001853:Bone Marrow / Q000473:pathology*; D002469:Cell Separation; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D059951:HLA-G Antigens / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007223:Infant; D039841:Leukocyte L1 Antigen Complex / Q000235:genetics* / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism; D009447:Neuroblastoma / Q000235:genetics* / Q000473:pathology*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D059951:HLA-G Antigens; D039841:Leukocyte L1 Antigen Complex; D009363:Neoplasm Proteins