Differential in vivo and in vitro HLA-G expression in melanoma cells: potential mechanisms.
The potential role of human leukocyte antigen G (HLA-G) in tumor immune escape has stimulated interest in the analysis of the expression of this molecule in malignant cells. In melanoma approximately 30% and less than 1% of surgically-removed lesions and cultured cell lines, respectively, have been found to express HLA-G protein. The reason for the marked difference in HLA-G expression frequency is unknown. Here we discuss the potential role of HLA-G detection methodology, stress factors in the tumor microenvironment, and epigenetic changes during tumor progression in the differential in vivo and in vitro HLA-G expression in melanoma cells. We propose a model that may account for the preferential in vivo HLA-G expression in melanoma cells. If proven correct, this model represents a useful background to investigate the mechanisms regulating HLA-G expression in melanoma cells and to devise strategies to counteract HLA-G expression in patients with melanoma.
Chang
Chien-Chung
CC
Department of Immunology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
Murphy
Shawn P
SP
Ferrone
Soldano
S
D000818:Animals; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D044127:Epigenesis, Genetic; D005434:Flow Cytometry; D006680:HLA Antigens / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D059951:HLA-G Antigens; D018869:Heat-Shock Response; D015395:Histocompatibility Antigens Class I / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D006801:Humans; D007157:Immunologic Surveillance; D008545:Melanoma / Q000276:immunology* / Q000378:metabolism; D018448:Models, Immunological; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000911:Antibodies, Monoclonal; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I