title: Promoter methylation and mRNA expression of HLA-G in relation to HLA-G protein expression in colorectal cancer.
abstract: Expression of human leukocyte antigen-G (HLA-G) is a suggested mechanism used by tumor cells to escape from host immune recognition and destruction. Advances in the field have made it evident that HLA-G is expressed in different types of malignancies including colorectal cancer (CRC). We analyzed HLA-G expression in 21 low passage CRC cell lines. The level of DNA methylation of the HLA-G gene and the presence of mRNA encoding HLA-G was measured. Moreover, HLA-G protein expression was determined by flow cytometry and immunohistochemistry (IHC). IHC was performed with three different monoclonal antibodies (mAbs) (4H84, MEM-G/1 and MEM-G/2). In addition, HLA-G protein expression was measured in matching primary tumor tissues. RNA analysis using RT-PCR followed by sequencing in 6 samples indicated strong homology of the PCR product with HLA-G3 in 5 samples. In accordance, in none of the cell lines, HLA-G1 expression was detected by flow-cytometry. Furthermore, no association between HLA-G DNA methylation patterns and HLA-G mRNA expression was observed. In addition, different immunohistochemical staining profiles among various anti-HLA-G mAbs were observed. In conclusion, the results of this study show that the HLA-G3 isoform was expressed in some of the CRC cell lines irrespective of the level of DNA methylation of HLA-G.
authors.affiliation: Dept. of Surgery, Leiden University Medical Center, Leiden, The Netherlands; Dept. of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Marloes
authors.initials: M
authors.lastname: Swets
authors.affiliation: Dept. of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Lina
authors.initials: L
authors.lastname: Seneby
authors.affiliation: Dept. of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Arnoud
authors.initials: A
authors.lastname: Boot
authors.affiliation: Dept. of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Tom
authors.initials: T
authors.lastname: van Wezel
authors.affiliation: Dept. of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: Gelderblom
authors.affiliation: Dept. of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Cornelis J H
authors.initials: CJ
authors.lastname: van de Velde
authors.affiliation: Dept. of Pathology, VU University Medical Center, Amsterdam, The Netherlands; Dept. of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: van den Elsen
authors.affiliation: Dept. of Surgery, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: P.J.K.Kuppen@lumc.nl.
authors.forename: Peter J K
authors.initials: PJ
authors.lastname: Kuppen
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000378:metabolism; D045744:Cell Line, Tumor; D002469:Cell Separation; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism; D019175:DNA Methylation; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D059951:HLA-G Antigens / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D019139:Tumor Escape
chemical_list: D000911:Antibodies, Monoclonal; D059951:HLA-G Antigens; D012333:RNA, Messenger
keywords: Cancer cell lines; Colorectal cancer; DNA methylation; HLA-G