IFN-alpha mediates the up-regulation of HLA class I on melanoma cells without switching proteasome to immunoproteasome.
Treatment of melanoma cell lines with IFN-gamma induces the switch from proteasome (PS) to immunoproteasome (iPS). This finding has profound implications for the immunobiology of melanoma cells since certain peptides (such as Melan-A(mart1)(27-35)) are cleaved differently by iPS, thus implying a different ability to be presented by HLA class I molecules. IFN-alpha is a cytokine not only produced during infectious diseases, but also used in the treatment of certain cancers. Nevertheless, the effects of IFN-alpha on the switch of PS to iPS are largely unknown. A comparison of the effect of both IFN-alpha and IFN-gamma was thus carried out on melanoma cell lines. RT-PCR showed that mRNA for iPS subunits (i.e. LMP-2, LMP-7 and MECL-1) was detectable both in untreated and IFN-treated melanoma cells. Immunoblotting analysis revealed that while IFN-gamma was able to consistently induce the switch from PS to iPS, IFN-alpha treatment did not, possibly due to post-transcriptional event(s) blocking the expression of iPS-specific subunits. Finally, Melan-A(mart1)(27-35) peptide was found only in the HPLC-MS spectra from both untreated and IFN-alpha-treated cells, but not upon IFN-gamma treatment. Altogether, these data demonstrate that IFN-alpha does not induce the switch from PS to iPS.
Cangemi
Giuliana
G
Laboratorio di Analisi, Istituto Giannina Gaslini, 16148 Genoa, Italy.
Morandi
Barbara
B
D'Agostino
Antonella
A
Peri
Cristiano
C
Conte
Romana
R
Damonte
Gianluca
G
Ferlazzo
Guido
G
Biassoni
Roberto
R
Melioli
Giovanni
G
D000906:Antibodies / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm; D015153:Blotting, Western; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry; D008401:Gas Chromatography-Mass Spectrometry; D015972:Gene Expression Regulation, Neoplastic; D015395:Histocompatibility Antigens Class I / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology / Q000502:physiology*; D007371:Interferon-gamma / Q000494:pharmacology / Q000502:physiology; D058965:MART-1 Antigen; D008545:Melanoma / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D009097:Multienzyme Complexes / Q000276:immunology* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000276:immunology / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D000906:Antibodies; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D015395:Histocompatibility Antigens Class I; D016898:Interferon-alpha; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009097:Multienzyme Complexes; D009363:Neoplasm Proteins; C071313:LMP-2 protein; D007371:Interferon-gamma; D003546:Cysteine Endopeptidases; C098949:proteasome subunit Z; C077436:LMP7 protein; C098948:PSMB10 protein, human; C088875:PSMB6 protein, human; D046988:Proteasome Endopeptidase Complex