title: Cancer immunoediting from immunosurveillance to tumor escape in microvillus-formed niche: a study of syngeneic orthotopic rat bladder cancer model in comparison with human bladder cancer.
abstract: Cancer cells can develop an attenuated immunogenicity and/or create an immunosuppressive microenvironment to prevent tumor eradication by host immune system, the so-called "cancer immunoediting" hypothesis. The aim of the present study was to find evidence for this hypothesis by using a rat orthotopic bladder cancer model. Fisher rats were inoculated with AY-27 cells (a Fisher rat bladder cancer cell line). Cultured cancer cells, rat and human bladder cancer tissues, and publicly available microarray data from human bladder cancer were analyzed by means of bioinformatics and morphology. Results showed that 12 of 24 differentially expressed pathways were concordant in connection to cell cycle and proliferation between rats and humans (both non-muscle-invasive and muscle-invasive tumors) and that 11 of the 24 pathways, including major histocompatibility complex, were related to host immunosurveillance with activations of T cells and natural killer cells in rats. The altered pathways and morphogenesis of this rat model corresponded more closely with those of human muscle-invasive rather than non-muscle-invasive tumors. A unique ultrastructure displaying microvillus-formed niches was found in small areas within the tumor of both rats and humans. These niches were interconnected with desmosomes between cancer cells and without infiltration of lymphocytes. The expression of E-cadherin, selectins, PGP9.5, vascular endothelial growth factor, caspase-3, CD133, Oct-4, nestin, CD3, and CD45RA was lower in the tumor than in the adjacent normal epithelium. We suggest that the microvillus-formed niche that harbors a few implanted cancer cells might be the compartment that prevents the tumor eradication by the host immune system.
authors.affiliation: Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Carl-Jørgen
authors.initials: CJ
authors.lastname: Arum
authors.forename: Endre
authors.initials: E
authors.lastname: Anderssen
authors.forename: Trond
authors.initials: T
authors.lastname: Viset
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kodama
authors.forename: Steinar
authors.initials: S
authors.lastname: Lundgren
authors.forename: Duan
authors.initials: D
authors.lastname: Chen
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Zhao
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D015820:Cadherins / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007124:Immunoenzyme Techniques; D008871:Microvilli / Q000473:pathology / Q000648:ultrastructure*; D015166:Monitoring, Immunologic; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011916:Rats, Inbred F344; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D019139:Tumor Escape; D001743:Urinary Bladder / Q000276:immunology*; D001749:Urinary Bladder Neoplasms / Q000276:immunology* / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D012333:RNA, Messenger