Lack of HLA class I antigen expression by melanoma cells SK-MEL-33 caused by a reading frameshift in beta 2-microglobulin messenger RNA.

Abstract

The lack of HLA class I antigen expression by the melanoma cell line SK-MEL-33 is caused by a unique lesion in p2-microglobulin (02-M). Sequencing of 2-A mRNA detected a guanosine deletion at position 323 in codon 76 that causes a frameshift with a subsequent introduction of a stop codon at a position 54 base upstream of the normal position of the stop codon in the message. The loss of 18 amino acids and the change of 6 amino acids, including a cysteine at position 80 in the carboxy terminus of fl2-M, are likely to cause marked changes in the structure of the polypeptide. The latter may account for the inability of 02-M to associate with HLA class I heavy chains and for its lack of reactivity with the anti-iB2-M mAb tested. HLA class I antigen expression on SK-MEL-33 cells was reconstituted after transfection with a wild-type B2m gene, therefore indicating that the abnormality of endogenous B2m gene is the only mechanism underlying lack of HLA class I antigen expression by SK-MEL-33 cells. The guanosine deletion in B2m gene was detected also in the melanoma tissue from which SK-MEL-33 cells had originated. Therefore, the molecular lesion identified in the SK-MEL-33 melanoma cell line is not caused by a mutation acquired during growth in vitro but is likely to reflect a somatic mutation during tumor progression. (J. Clin. Invest. 1993. 91:684-692.)

Immune Selection of Hot-Spot β2-Microglobulin Gene Mutations, HLA-A2 Allospecificity Loss, and Antigen-Processing Machinery Component Down-Regulation in Melanoma Cells Derived from Recurrent Metastases following Immunotherapy

“…It remains to be determined whether ␤ 2 m-transfected 1259MEL cells are sensitive to lysis by autologous, MA-specific CTL. In contrast, the detection of HLA*0201-MART1 [27][28][29][30][31][32][33][34][35] peptide complexes by the ␤ 2 m-transfected HLA-A2 ϩ 1074MEL cells (1074MEL.␤2.7) suggests that 1074MEL cells carry a functional APM capable of generating HLA class I Ag-restricted, MA-derived peptides. Furthermore, this result parallels our previous finding that ␤ 2 m-transduced 1074MEL cells were susceptible to lysis by HLA-A2 Ag-restricted, MA-specific CTL (8).…”

“…The monomeric HLA-A*0201-MART1 27-35 -specific scFv 8.3 was isolated from the human synthetic V H ϩ V L scFv library (Griffin.1 library) by panning with HLA-A*0201-MART1 [27][28][29][30][31][32][33][34][35] peptide complexes (M. Campoli, unpublished results). To construct tetrameric scFv 8.3, monomeric scFv 8.3 were engineered with a C-terminal BirA biotinylation tag (scFv 8.3-BirA) and expressed from ampicillin-resistant bacterial colonies, as previously described (24 -26).…”

“…To determine the functionality of APM in melanoma cells analyzed in this study, we assessed HLA-A*0201-MART1 [27][28][29][30][31][32][33][34][35] …”

Metastatic potential of human melanoma cells in nude mice - characterisation of phenotype, cytokine secretion and tumour-associated antigens

“…Interestingly, UKRV-Mel-2, which completely lacked any HLA-class I molecule expression on its cell surface was characterised by a poor growth rate in nude mice without development of metastases, independent of inoculation route. UKRV-MEL-2 is only the third human melanoma cell line besides FO-1 (D'Urso et al, 1991) and (Wang et al, 1993) that completely lacks HLAclass I expression, which is caused in FO-l and SK-Mel-33 by firmicroglobulin mutations. However, the reason for the missing expression in UKRV-Mel-2 is presently unknown.…”

Loss of single HLA Class I allospecificities in melanoma cells due to selective genomic abbreviations

“…5,6 In the case of malignant melanoma (MM), downregulation of HLA Class I expression is correlated with poor prognosis. 7 In MM several mechanisms that are responsible for abnormal levels of expression of HLA Class I molecules have been described: (i) nonfunctional ␤2m 8 or microsatellite instability, 9 leading to total loss of HLA Class I; (ii) genomic haplotype loss; 6 (iii) locus specific downregulation; 10,11 and (iv) selective loss of single HLA Class I allospecificities. 12,13 Similar observations have also been described in vitro in other human malignancies such as cervical carcinomas 14 and lymphoblastoid tumors.…”