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T cell recognition of HLA‐A2 restricted tumor antigens is impaired by the oncogene HER2
Author(s) -
Mimura Kousaku,
Ando Takashi,
Poschke Isabel,
Mougiakakos Dimitrios,
Johansson C. Christian,
Ichikawa Jiro,
Okita Riki,
Nishimura Michael I.,
Handke Diana,
Krug Nancy,
Choudhury Aniruddha,
Seliger Barbara,
Kiessling Rolf
Publication year - 2010
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.25613
Subject(s) - major histocompatibility complex , biology , human leukocyte antigen , cytotoxic t cell , antigen , mhc class i , melanoma , cd8 , immunology , immunotherapy , antigen presentation , cancer research , antigen processing , immune system , t cell , genetics , in vitro
The HER2 oncogene is frequently over‐expressed in human cancers and a promising target for immune therapy. Previous studies have shown that over‐expression of mouse or rat HER2 leads to markedly reduced levels of major histocompatibility complex (MHC) class I and molecules of the antigen processing and presentation machinery (APM), thus resulting in a phenotype promoting tumor escape from the immune system. Our study focuses on analyzing the effect of HER2 on MHC class I antigen presentation and sensitivity to tumor‐antigen specific cytotoxic T lymphocytes (CTLs) in HLA‐A2.1 + melanoma cell lines. We demonstrate significant inverse correlations both between the expression of HER2 and total MHC class I surface expression as well as between HER2 and HLA‐A2. A significant reduction of HLA‐A2 levels was found when melanoma and carcinoma cell lines were transfected with a human HER2 gene. A signaling‐competent HER2 molecule was crucial for the observed HLA‐A2 down‐regulation, as transfectants expressing high levels of HER2 mutated in the tyrosine signaling domain did not show altered HLA‐A2 expression. Importantly, the human melanoma cell line EST049 demonstrated reduced HER2 and melanoma antigen‐specific recognition by CTLs upon HER2 transfection. In addition, high expression of HER2 prevented both IFN‐γ mediated HLA‐A2 up‐regulation and improved recognition by HLA‐A2‐restricted CTLs in treated cells. Moreover, key APM molecules were down‐regulated by HER2. These findings implicate that HER2 over‐expressing tumors may be more prone to escape from HLA‐A2 restricted CTLs suggesting that immunotherapy approaches inducing an integrated humoral, cellular and innate immune response would be most effective.