Impaired expression of proteasome subunits and human leukocyte antigens class I in human colon cancer cells

• Published in: Journal of gastroenterology and hepatology 2003-01, Vol.18 (1), p.32-40
• Main Authors: MIYAGI, TAKUYA, TATSUMI, TOMOHIDE, TAKEHARA, TETSUO, KANTO, TATSUYA, KUZUSHITA, NORIYOSHI, SUGIMOTO, YOSHIKO, JINUSHI, MASAHISA, KASAHARA, AKINORI, SASAKI, YUTAKA, HORI, MASATSUGU, HAYASHI, NORIO
• Format: Article
• Language: English
• Subjects: Animals; ATP Binding Cassette Transporter, Subfamily B, Member 2; ATP Binding Cassette Transporter, Subfamily B, Member 3; ATP-Binding Cassette Transporters - genetics; beta 2-Microglobulin - genetics; Biological and medical sciences; colon cancer; Colonic Neoplasms - metabolism; Cysteine Endopeptidases - genetics; Cysteine Endopeptidases - metabolism; Flow Cytometry; Gastroenterology. Liver. Pancreas. Abdomen; Histocompatibility Antigens Class I - metabolism; HLA-A Antigens - genetics; HLA-B Antigens - genetics; HLA-C Antigens - genetics; human leukocyte antigen class I; Humans; immunoproteasomes; Interferon-gamma - pharmacology; Isoenzymes - genetics; Isoenzymes - metabolism; Medical sciences; Mice; Multienzyme Complexes - genetics; Multienzyme Complexes - metabolism; Muscle Proteins; proteasome activator 28; Proteasome Endopeptidase Complex; proteasome subunits; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Transfection; Tumor Cells, Cultured; Tumors
• ISSN: 0815-9319; 1440-1746
• DOI: 10.1046/j.1440-1746.2003.02921.x

Background and Aim: The presentation of human leukocyte antigens (HLA) class I requires the coordinated expression of numerous components involved in antigen processing and antigen presentation. Tumor cells may alter the expression of these components to decrease HLA class I expression, allowing them to escape immune surveillance. The aim of this study is to investigate the expressions of these components, including proteasome subunits, and their involvement in the expression of HLA class I in human colon cancer cells. Methods: Four human colon cancer cell lines, HCT116, SW403, LoVo and DLD‐1, were used to examine the expression of HLA class I by flow cytometry. Reverse transcription–polymerase chain reaction was performed to assess the expression of β2‐microglobulin, heavy chains, transporter subunits, immunoproteasomes subunits and proteasome activator 28 (PA28) subunits. Results: Human leukocyte antigen class I was expressed highly in HCT116 and SW403 cells and weakly in LoVo cells, but was not expressed in DLD‐1 cells. The DLD‐1 cells were deficient in the expression of proteasome subunits including low molecular weight polypeptide proteasome subunit 2 (LMP2), multicatalytic endopeptidase complex‐like‐1 (MECL‐1), PA28α and PA28β, whereas other HLA class I‐expressing cell lines expressed all components tested. γ‐Interferon (IFN‐γ) treatment of DLD‐1 cells restored the expression of LMP2, MECL‐1 and PA28β, but not the expression of HLA class I. Enforced expression of PA28α induced the expression of HLA class I in IFN‐γ‐treated DLD‐1 cells, but not in untreated DLD‐1 cells. Conclusion: These results suggest that the impaired expression of proteasome subunits is involved in the loss of HLA class I expression in human colon cancer cells. © 2003 Blackwell Publishing Asia Pty Ltd