Cangemi Giuliana, Morandi Barbara, D'Agostino Antonella, Peri Cristiano, Conte Romana, Damonte Gianluca, Ferlazzo Guido, Biassoni Roberto, Melioli Giovanni
Laboratorio di Analisi, Istituto Giannina Gaslini, 16148 Genoa, Italy.
Int Immunol. 2003 Dec;15(12):1415-21. doi: 10.1093/intimm/dxg140.
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.
用γ干扰素处理黑色素瘤细胞系可诱导其从蛋白酶体（PS）转变为免疫蛋白酶体（iPS）。这一发现对黑色素瘤细胞的免疫生物学具有深远意义，因为某些肽段（如黑色素瘤抗原A（mart1）（27 - 35））被iPS切割的方式不同，这意味着其由I类人白细胞抗原分子呈递的能力也不同。α干扰素不仅是在感染性疾病期间产生的一种细胞因子，也被用于某些癌症的治疗。然而，α干扰素对PS向iPS转变的影响在很大程度上尚不清楚。因此，对黑色素瘤细胞系进行了α干扰素和γ干扰素作用效果的比较。逆转录 - 聚合酶链反应显示，在未处理和经干扰素处理的黑色素瘤细胞中均能检测到iPS亚基（即低分子量多肽2（LMP - 2）、低分子量多肽7（LMP - 7）和MECL - 1）的信使核糖核酸。免疫印迹分析表明，虽然γ干扰素能够持续诱导从PS到iPS的转变，但α干扰素处理却不能，这可能是由于转录后事件阻断了iPS特异性亚基的表达。最后，仅在未处理和经α干扰素处理的细胞的高效液相色谱 - 质谱图谱中发现了黑色素瘤抗原A（mart1）（27 - 35）肽段，而在经γ干扰素处理的细胞中未发现。总之，这些数据表明α干扰素不会诱导从PS到iPS的转变。
