Comparison of the interferon-gamma-mediated regulation of tumor-associated antigens expressed by human gastric carcinoma cells

Abstract

The regulation by interferon-gamma (IFN-gamma) of the expression of seven distinct human tumor-associated antigens [M 110,000, carcinoembryonic antigen (CEA), nonspecific crossreacting antigen (NCA), CA19-9, 17-1A, TAG-72, and D612] was studied in eight human gastric cancer cell lines. Six of the seven tumor antigens have been well-characterized and reported to be expressed by human gastric carcinomas. The M(r) 110,000 antigen has been recently identified in six of the eight human gastric cancer cell lines and may represent a potentially novel gastric tumor antigen. IFN-gamma administration substantially increased the expression of the M(r) 110,000 antigen in six gastric tumor cell types, and, furthermore, induced its expression de novo in another gastric tumor cell line (GaCa). Constitutive CEA and NCA expression was detected on the surface of five of the eight gastric carcinoma cell lines. IFN-gamma treatment induced only a modest increase in the level of expression of those related antigens, but those changes were accompanied by increases in the level of the respective mRNA transcripts. Four other human tumor-associated antigens, TAG-72, CA19-9, D612, and 17-1A, were found either to be not constitutively expressed and/or not regulated by IFN-gamma. The results indicate the selective nature by which IFN-gamma regulates the M(r) 110,000 antigen and, to a lesser extent, the antigens of the CEA gene family.