Lack of class II transactivator causes severe deficiency of HLA-DR expression in small cell lung cancer

✍ Scribed by Yazawa, Takuya; Kamma, Hiroshi; Fujiwara, Masachika; Matsui, Miwa; Horiguchi, Hisashi; Satoh, Hiroaki; Fujimoto, Mitsuo; Yokoyama, Koichi; Ogata, Takesaburo

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 536 KB
• Volume: 187
• Category: Article
• ISSN: 0022-3417
• DOI: 10.1002/(sici)1096-9896(199901)187:2<191::aid-path206>3.0.co;2-3

✦ Synopsis

Small cell lung cancer (SCLC) is characteristically not associated with tumour-infiltrating lymphocytes. Since SCLC has been reported to show marked reduction of class I HLA, the reduced expression has been considered a means of escaping anti-cancer immunity. However, HLA-DR expressed in cancer cells is now known to contribute to anti-cancer immunity. To clarify the difference in HLA-DR expression between SCLC and non-small cell lung cancer (NSCLC), and the mechanism, the expression and the cis- and trans-acting factors involved were investigated. HLA-DR was not immunohistochemically detected in any SCLC and could not be induced by interferon gamma (IFN-gamma) in any SCLC cell line, whereas HLA-DR was expressed to varying degrees and was easily induced in NSCLC. SCLC cell lines lacked class II transactivator (CIITA) even after IFN-gamma induction, whereas NSCLC cell lines expressed CIITA. The other class II HLA-specific transcription factors were expressed and genomic DNA of HLA-DR, including the promoter, was conserved well both in SCLC and in NSCLC cell lines. CIITA transfection improved the expression of HLA-DR in SCLC. In conclusion, the lack of CIITA results in severe deficiency of HLA-DR expression in SCLC. Since CIITA has also been reported to induce class I HLA, CIITA transfection might make it possible to establish effective anti-cancer immunotherapy against SCLC through the up-regulation of class I and class II HLA.