Ionizing radiation modulates the surface expression of human leukocyte antigen-G in a human melanoma cell line.
Human leukocyte antigen G (HLA-G) is a nonclassical HLA class I molecule involved in fetus protection from the maternal immune system, transplant tolerance, and viral and tumoral immune escape. Tumor-specific HLA-G expression has been described for a wide variety of malignancies, including melanomas. The aim of this study was to evaluate whether ionizing radiation (IR) could modulate the surface expression of HLA-G1 in a human melanoma cell line that expresses endogenously membrane-bound HLA-G1. For this purpose, cells were exposed to increasing doses of gamma-irradiation (0-20 Gy) and HLA-G1 levels at the plasma membrane were analyzed at different times postirradiation by flow cytometry. HLA-G total expression and the presence of the soluble form of HLA-G1 (sHLA-G1) in the culture medium of irradiated cells were also evaluated. IR was capable of downregulating cell surface and total HLA-G levels, with a concomitant increase of sHLA-G1 in the medium. These results could indicate that gamma-irradiation decreases HLA-G1 surface levels by enhancing the proteolytic cleavage of this molecule.
Michelin
Severino
S
Radiopathology Laboratory, Nuclear Regulatory Authority, Buenos Aires, Argentina. smicheli@cae.arn.gov.ar
Gallegos
Cristina E
CE
Dubner
Diana
D
Favier
Benoit
B
Carosella
Edgardo D
ED
D002453:Cell Cycle / Q000528:radiation effects; D045744:Cell Line, Tumor; D005720:Gamma Rays; D006680:HLA Antigens / Q000378:metabolism* / Q000528:radiation effects*; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000378:metabolism* / Q000528:radiation effects*; D006801:Humans; D008545:Melanoma / Q000378:metabolism*; D012878:Skin Neoplasms / Q000378:metabolism*; D000097625:HLA-E Antigens
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I; D000097625:HLA-E Antigens