Recognition of pleural mesothelioma by mucin-1(950-958)/human leukocyte antigen A\*0201-specific CD8+ T-cells

Our plain-English summary of Recognition of pleural mesothelioma by mucin-1(950-958)/human leukocyte antigen A*0201-specific CD8+ T-cells, by D. Roulois, V. Vignard, F. Gueugnon, et al (The European Respiratory Journal, 2011).

The study

• Authors: D. Roulois, V. Vignard, F. Gueugnon, N. Labarrière, M. Grégoire, J.F. Fonteneau
• Journal: The European Respiratory Journal
• Published: 2011;38(5):1117-26
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Recent clinical investigations have demonstrated that T-cell-based immunotherapy of malignant pleural mesothelioma (MPM) could represent an alternative to the other therapeutic strategies. However, its development suffers from the lack of identified tumour antigenic targets. Mucin (MUC)1, which is expressed and recognised by cytotoxic T-cells in numerous cancer types, has not been investigated as a potential immune target in MPM. Thus, the objective of this study was to analyse MUC1 expression by MPM cells and to determine whether this antigen can be the target of cytotoxic CD8+ T-cells (cytotoxic T-lymphocytes (CTLs)). We first evaluated the expression and glycosylation of MUC1 by MPM cell lines using different MUC1-specific monoclonal antibodies. We then obtained a CTL clone specific for a MUC1 peptide (residues 950-958) presented by human leukocyte antigen (HLA)-A*0201 and studied its interferon-γ and cytotoxic response to MPM cell lines. We found that all MPM cell lines expressed MUC1 protein at the cell surface with different glycosylation profiles. We also observed that HLA-A*0201+ MPM cell lines are recognised and lysed by a HLA-A*0201/MUC1(950-958)-specific CTL clone independently of the MUC1 glycosylation profile. Thus, MUC1 expression and antigen presentation by MPM cells may represent an attractive target for immunotherapeutic treatment of MPM despite its hyperglycosylated profile.

In plain English

This was a laboratory (in vitro) study carried out in Nantes, France, on malignant pleural mesothelioma (MPM), which the authors describe as usually associated with chronic asbestos exposure. The authors tested 12 human MPM cell lines established from pleural effusions, plus two breast cancer lines, for surface mucin-1 (MUC1) using three antibodies recognising different glycosylation states, and for HLA class I, CD54 and CD58. From blood of HLA-A*0201-positive healthy donors they generated CD8+ T-cell (cytotoxic T-lymphocyte) clones against the MUC1(950-958) peptide. MUC1 was found on the surface of every MPM cell line tested, with relative fluorescence intensity (HMFG-1) ranging from 7.6 for Meso47 to 105.2 for Meso56, and with varying glycosylation. The higher-avidity clone N5.14 produced interferon-gamma in response to all HLA-A*0201-positive MPM lines and lysed three of them in a 4-hour chromium-release assay; the two HLA-A*0201-negative lines were not recognised, and Meso13, the only negative line used in the killing assay, was not killed. Reducing O-glycosylation with the competitive inhibitor BGN did not change recognition. The authors concluded that MUC1 may be an attractive immunotherapy target in MPM.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory (in vitro) study using human mesothelioma cell lines and peptide-specific CD8+ T-cell clones
• Who was studied: Twelve human malignant pleural mesothelioma cell lines obtained from pleural effusions (all epithelioid), two breast cancer cell lines (MDA-MB231, MCF-7), the T2 cell line, and blood from HLA-A*0201-positive healthy donors; Nantes, France
• Exposure: Not an asbestos-exposure study: the tested variable was the MUC1 antigen, its glycosylation state, and recognition of MPM cells by MUC1(950-958)/HLA-A*0201-specific CD8+ T-cell clones; cells were also treated with interferon-gamma or with the O-glycosylation inhibitor BGN
• Main results:
  • MUC1 was detected on the surface of all MPM cell lines tested, with HMFG-1 relative fluorescence intensity from 7.6 (Meso47) to 105.2 (Meso56)
  • All MPM cell lines stained positive for HLA class I, CD54 and CD58, except Meso34 which had low CD54
  • MUC1(950-958)-specific CD8+ T-cells were obtained from nine of 80 microcultures of donor T-cells; two clones (N5.14, N32.10) were isolated
  • Clone N5.14 had higher avidity for the MUC1(950-958) peptide than clone N32.10
  • Clone N5.14 produced interferon-gamma against all HLA-A*0201-positive MPM cell lines tested, but not against the HLA-A*0201-negative lines Meso4 and Meso13; clone N32.10 recognised none of the MPM lines
  • Pre-treating the tumour cells with interferon-gamma increased the N5.14 response when results for all MPM cell lines were pooled (p=0.0164, Mann-Whitney U-test)
  • Adding an anti-HLA-A*0201 antibody to the T-cell clone/MPM co-culture inhibited the interferon-gamma response of clone N5.14 by 60-70%
  • In a 4-hour chromium-release assay clone N5.14 killed the three HLA-A*0201-positive lines Meso35, Meso62 and Meso144, while the HLA-A*0201-negative line Meso13, used as the control in that assay, was not killed
  • BGN, a competitive inhibitor of O-glycosylation, increased SM3 and VU-3-C6 staining (reduced MUC1 glycosylation) but T-cell clone responses were similar in treated and untreated MPM cell lines
  • T-cell clone responses were similar in BGN-treated and untreated cell lines
• The authors' conclusion: The authors concluded that MUC1 expression and antigen presentation by MPM cells may be an attractive target for immunotherapy of MPM despite the hyperglycosylated profile, and that such treatments should aim at inducing high-avidity T-cells
• Limitations the authors state:
  • The authors noted that antibody staining reflects not only the amount of surface MUC1 but also the number of variable number tandem repeats, so staining levels are not a direct measure of MUC1 quantity
  • The authors noted that surface MUC1 does not represent total MUC1 expressed by tumour cells, because it depends on turnover and cleavage by sheddases
  • The authors reported that their results only partly confirmed earlier observations, as they did not confirm altered glycosylation of MUC1 in most cell lines

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Immunotherapy, Monoclonal Antibody.

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