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MELOE-1 is a new antigen overexpressed in melanomas and involved in adoptive T cell transfer efficiency.

Godet Y, Moreau-Aubry A, Guilloux Y, Vignard V, Khammari A, Dreno B, Jotereau F, Labarriere N - J. Exp. Med. (2008)

Bottom Line: Remarkably, the structure of meloe was unusual, with multiple short open reading frames (ORFs).The peptide recognized by the CTL clone was encoded by one of these ORFs, called MELOE-1.Using a specific HLA-A2/peptide tetramer, we showed a correlation between the infusion of TILs containing MELOE-1-specific T cells and relapse prevention in HLA-A2 patients.

View Article: PubMed Central - PubMed

Affiliation: Institut National de Santé et de Recherche Médicale, Unité Mixte de Recherche 892, 44093 Nantes, France.

ABSTRACT
A cytotoxic T lymphocyte (CTL) clone was derived from a tumor-infiltrating lymphocyte (TIL) population infused to a melanoma patient who remained relapse free for 10 yr after this adoptive transfer. This clone recognized all melanoma cell lines tested and, to a lower extent, melanocytes, in the context of human histocompatibility leukocyte antigen A2 (HLA-A2), but it did not recognize other tumor cell types. The gene coding for the antigen recognized by this clone was identified by the screening of a melanoma complementary DNA expression library. This antigen is overexpressed in melanomas, compared with other cancer cell lines and healthy tissues, and was thus called melanoma-overexpressed antigen (meloe). Remarkably, the structure of meloe was unusual, with multiple short open reading frames (ORFs). The peptide recognized by the CTL clone was encoded by one of these ORFs, called MELOE-1. Using a specific HLA-A2/peptide tetramer, we showed a correlation between the infusion of TILs containing MELOE-1-specific T cells and relapse prevention in HLA-A2 patients. Indeed, 5 out of 9 patients who did not relapse were infused with TILs that contained MELOE-1-specific T cells, whereas 0 out of the 21 patients who relapsed was infused with such TIL-containing lymphocytes. Overall, our results suggest that this new antigen is involved in immunosurveillance and, thus, represents an attractive target for immunotherapy protocols of melanoma.

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Preferential expression of meloe cDNA in melanoma cell lines measured by qPCR, and impact of meloe expression on specific CTL clone activation. (A) Four melanoma, one breast cancer, two renal carcinoma, and one lung cancer cell lines were tested by qPCR for the expression of meloe. RPLPO and β2-microglobulin gene expression were used as internal controls. The relative expression of meloe was calculated after normalization on the efficiency of the PCR reaction and the mean expression of these two housekeeping genes, reported to its normalized expression in melanocytes. (B) TNF secretion by the M170.48 CTL clone in response to HLA-A2 tumor cell lines nontransfected (open bars) or transfected with meloe (hatched bars) or meloe-1 (shaded bars) expression plasmids. Tumor cells were transiently transfected with 100 ng of each plasmid with a lipofectamine reagent kit. 104 CTLs were added to 3 × 104 target cells, and the CTL clone reactivity was assessed by a TNF release assay. (C) meloe relative expression measured by qPCR in 16 human healthy tissues.
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fig4: Preferential expression of meloe cDNA in melanoma cell lines measured by qPCR, and impact of meloe expression on specific CTL clone activation. (A) Four melanoma, one breast cancer, two renal carcinoma, and one lung cancer cell lines were tested by qPCR for the expression of meloe. RPLPO and β2-microglobulin gene expression were used as internal controls. The relative expression of meloe was calculated after normalization on the efficiency of the PCR reaction and the mean expression of these two housekeeping genes, reported to its normalized expression in melanocytes. (B) TNF secretion by the M170.48 CTL clone in response to HLA-A2 tumor cell lines nontransfected (open bars) or transfected with meloe (hatched bars) or meloe-1 (shaded bars) expression plasmids. Tumor cells were transiently transfected with 100 ng of each plasmid with a lipofectamine reagent kit. 104 CTLs were added to 3 × 104 target cells, and the CTL clone reactivity was assessed by a TNF release assay. (C) meloe relative expression measured by qPCR in 16 human healthy tissues.

Mentions: To explain the absence of recognition of tumor cell lines other than melanomas, we examined the transcription level of meloe cDNA by quantitative PCR (qPCR; Table II) in a panel of HLA-A2 tumor cell lines and melanocytes. The mean level of meloe expression in two HLA-A2 melanocytes was used as a reference to establish its relative expression in other cell lines. This analysis showed that meloe expression in melanomas was higher than in melanocytes, with values ranging from 3- to 34-fold higher, whereas this expression was significantly lower in other tumor cell lines, with values ranging from 5- to 338-fold lower (Fig. 4 A). These results show that this antigen is overexpressed in melanomas, and thus, the protein encoded by the ORF 1,230–1,370 was called MELOE-1. Furthermore, transfection of meloe or meloe-1 cDNA in HLA-A2 nonrecognized tumor cell lines induced their recognition by the M170.48 T cell clone (Fig. 4 B), showing that the absence of recognition of these tumor cell lines was caused by the underexpression of meloe cDNA. Finally, to address the question of the expression of this antigen in healthy tissues, we performed qPCR on a panel of 16 tissues. It appears that the expression of meloe in healthy tissues was always lower than in melanocytes. The highest meloe expression was found in the whole and fetal brain but remained, respectively, 1.5- and 1.8-fold below its expression in melanocytes (Fig. 4 C). Overall, these results suggest that this antigen could be safely targeted in immunotherapy protocols in melanoma, provided that its immunogenicity could be documented.


MELOE-1 is a new antigen overexpressed in melanomas and involved in adoptive T cell transfer efficiency.

Godet Y, Moreau-Aubry A, Guilloux Y, Vignard V, Khammari A, Dreno B, Jotereau F, Labarriere N - J. Exp. Med. (2008)

Preferential expression of meloe cDNA in melanoma cell lines measured by qPCR, and impact of meloe expression on specific CTL clone activation. (A) Four melanoma, one breast cancer, two renal carcinoma, and one lung cancer cell lines were tested by qPCR for the expression of meloe. RPLPO and β2-microglobulin gene expression were used as internal controls. The relative expression of meloe was calculated after normalization on the efficiency of the PCR reaction and the mean expression of these two housekeeping genes, reported to its normalized expression in melanocytes. (B) TNF secretion by the M170.48 CTL clone in response to HLA-A2 tumor cell lines nontransfected (open bars) or transfected with meloe (hatched bars) or meloe-1 (shaded bars) expression plasmids. Tumor cells were transiently transfected with 100 ng of each plasmid with a lipofectamine reagent kit. 104 CTLs were added to 3 × 104 target cells, and the CTL clone reactivity was assessed by a TNF release assay. (C) meloe relative expression measured by qPCR in 16 human healthy tissues.
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fig4: Preferential expression of meloe cDNA in melanoma cell lines measured by qPCR, and impact of meloe expression on specific CTL clone activation. (A) Four melanoma, one breast cancer, two renal carcinoma, and one lung cancer cell lines were tested by qPCR for the expression of meloe. RPLPO and β2-microglobulin gene expression were used as internal controls. The relative expression of meloe was calculated after normalization on the efficiency of the PCR reaction and the mean expression of these two housekeeping genes, reported to its normalized expression in melanocytes. (B) TNF secretion by the M170.48 CTL clone in response to HLA-A2 tumor cell lines nontransfected (open bars) or transfected with meloe (hatched bars) or meloe-1 (shaded bars) expression plasmids. Tumor cells were transiently transfected with 100 ng of each plasmid with a lipofectamine reagent kit. 104 CTLs were added to 3 × 104 target cells, and the CTL clone reactivity was assessed by a TNF release assay. (C) meloe relative expression measured by qPCR in 16 human healthy tissues.
Mentions: To explain the absence of recognition of tumor cell lines other than melanomas, we examined the transcription level of meloe cDNA by quantitative PCR (qPCR; Table II) in a panel of HLA-A2 tumor cell lines and melanocytes. The mean level of meloe expression in two HLA-A2 melanocytes was used as a reference to establish its relative expression in other cell lines. This analysis showed that meloe expression in melanomas was higher than in melanocytes, with values ranging from 3- to 34-fold higher, whereas this expression was significantly lower in other tumor cell lines, with values ranging from 5- to 338-fold lower (Fig. 4 A). These results show that this antigen is overexpressed in melanomas, and thus, the protein encoded by the ORF 1,230–1,370 was called MELOE-1. Furthermore, transfection of meloe or meloe-1 cDNA in HLA-A2 nonrecognized tumor cell lines induced their recognition by the M170.48 T cell clone (Fig. 4 B), showing that the absence of recognition of these tumor cell lines was caused by the underexpression of meloe cDNA. Finally, to address the question of the expression of this antigen in healthy tissues, we performed qPCR on a panel of 16 tissues. It appears that the expression of meloe in healthy tissues was always lower than in melanocytes. The highest meloe expression was found in the whole and fetal brain but remained, respectively, 1.5- and 1.8-fold below its expression in melanocytes (Fig. 4 C). Overall, these results suggest that this antigen could be safely targeted in immunotherapy protocols in melanoma, provided that its immunogenicity could be documented.

Bottom Line: Remarkably, the structure of meloe was unusual, with multiple short open reading frames (ORFs).The peptide recognized by the CTL clone was encoded by one of these ORFs, called MELOE-1.Using a specific HLA-A2/peptide tetramer, we showed a correlation between the infusion of TILs containing MELOE-1-specific T cells and relapse prevention in HLA-A2 patients.

View Article: PubMed Central - PubMed

Affiliation: Institut National de Santé et de Recherche Médicale, Unité Mixte de Recherche 892, 44093 Nantes, France.

ABSTRACT
A cytotoxic T lymphocyte (CTL) clone was derived from a tumor-infiltrating lymphocyte (TIL) population infused to a melanoma patient who remained relapse free for 10 yr after this adoptive transfer. This clone recognized all melanoma cell lines tested and, to a lower extent, melanocytes, in the context of human histocompatibility leukocyte antigen A2 (HLA-A2), but it did not recognize other tumor cell types. The gene coding for the antigen recognized by this clone was identified by the screening of a melanoma complementary DNA expression library. This antigen is overexpressed in melanomas, compared with other cancer cell lines and healthy tissues, and was thus called melanoma-overexpressed antigen (meloe). Remarkably, the structure of meloe was unusual, with multiple short open reading frames (ORFs). The peptide recognized by the CTL clone was encoded by one of these ORFs, called MELOE-1. Using a specific HLA-A2/peptide tetramer, we showed a correlation between the infusion of TILs containing MELOE-1-specific T cells and relapse prevention in HLA-A2 patients. Indeed, 5 out of 9 patients who did not relapse were infused with TILs that contained MELOE-1-specific T cells, whereas 0 out of the 21 patients who relapsed was infused with such TIL-containing lymphocytes. Overall, our results suggest that this new antigen is involved in immunosurveillance and, thus, represents an attractive target for immunotherapy protocols of melanoma.

Show MeSH
Related in: MedlinePlus