title: CEACAM1 promotes melanoma cell growth through Sox-2.
abstract: The prognostic value of the carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) in melanoma was demonstrated more than a decade ago as superior to Breslow score. We have previously shown that intercellular homophilic CEACAM1 interactions protect melanoma cells from lymphocyte-mediated elimination. Here, we study the direct effects of CEACAM1 on melanoma cell biology. By employing tissue microarrays and low-passage primary cultures of metastatic melanoma, we show that CEACAM1 expression gradually increases from nevi to metastatic specimens, with a strong dominance of the CEACAM1-Long tail splice variant. Using experimental systems of CEACAM1 knockdown and overexpression of selective variants or truncation mutants, we prove that only the full-length long tail variant enhances melanoma cell proliferation in vitro and in vivo. This effect is not reversed with a CEACAM1-blocking antibody, suggesting that it is not mediated by intercellular homophilic interactions. Downstream, CEACAM1-Long increases the expression of Sox-2, which we show to be responsible for the CEACAM1-mediated enhanced proliferation. Furthermore, analysis of the CEACAM1 promoter reveals two single-nucleotide polymorphisms (SNPs) that significantly enhance the promoter's activity compared with the consensus nucleotides. Importantly, case-control genetic SNP analysis of 134 patients with melanoma and matched healthy donors show that patients with melanoma do not exhibit the Hardy-Weinberg balance and that homozygous SNP genotype enhances the hazard ratio to develop melanoma by 35%. These observations shed new mechanistic light on the role of CEACAM1 in melanoma, forming the basis for development of novel therapeutic and diagnostic technologies.
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel; Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Rona
authors.initials: R
authors.lastname: Ortenberg
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel; Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Gilli
authors.initials: G
authors.lastname: Galore-Haskel
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel.
authors.forename: Ilanit
authors.initials: I
authors.lastname: Greenberg
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel; Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Bella
authors.initials: B
authors.lastname: Zamlin
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel.
authors.forename: Sivan
authors.initials: S
authors.lastname: Sapoznik
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel; Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Greenberg
authors.affiliation: Institute of Pathology, Sheba Medical Center, Ramat-Gan 526260, Israel.
authors.forename: Iris
authors.initials: I
authors.lastname: Barshack
authors.affiliation: Institute of Pathology, Sheba Medical Center, Ramat-Gan 526260, Israel.
authors.forename: Camila
authors.initials: C
authors.lastname: Avivi
authors.affiliation: Cancer Research Center, Sheba Medical Center, Ramat-Gan, Israel.
authors.forename: Yulia
authors.initials: Y
authors.lastname: Feiler
authors.affiliation: Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Israel
authors.initials: I
authors.lastname: Zan-Bar
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel; Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Michal J
authors.initials: MJ
authors.lastname: Besser
authors.affiliation: Department of Dermatology, Sheba Medical Center, Ramat-Gan, Israel.
authors.forename: Ester
authors.initials: E
authors.lastname: Azizi
authors.affiliation: The Susanne-Levy Gertner Oncogenetics Unit, Danek Gertner Institute of Human Genetics, Ramat-Gan, Israel.
authors.forename: Friedman
authors.initials: F
authors.lastname: Eitan
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel.
authors.forename: Jacob
authors.initials: J
authors.lastname: Schachter
authors.affiliation: Ella Institute of Melanoma, Sheba Medical Center, Ramat-Gan, Israel; Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Talpiot Medical Leadership Program, Sheba Medical Center, Ramat-Gan, Israel. Electronic address: markel@post.tau.ac.il.
authors.forename: Gal
authors.initials: G
authors.lastname: Markel
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005434:Flow Cytometry; D055785:Gene Knockdown Techniques; D064593:Heterografts; D006801:Humans; D007150:Immunohistochemistry; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors / Q000378:metabolism*; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D046888:Tissue Array Analysis
chemical_list: D015703:Antigens, CD; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; D055748:SOXB1 Transcription Factors