Breast and ovarian cancer-specific cytotoxic T lymphocytes recognize the same HER2/neu-derived peptide.

Abstract

The identification of antigenic peptides presented on the tumor cell surface by HLA class I molecules and recognized by tumor-specific cytotoxic T lymphocytes may lead to a peptide vaccine capable of inducing protective cellular immunity. We demonstrate that both HLA-A2-restricted breast and ovarian tumor-specific cytotoxic T lymphocytes recognize shared (3) and MART (melanoma antigen recognized by T cells) (4) in melanoma. The discovery of these genes and peptides substantiates the existence of such antigen systems, but unfortunately, melanoma accounts for only 3% of all malignancies and 1% of all cancer deaths (5).HLA-A2 is expressed in approximately 50% of Caucasians (6) and has been demonstrated to play a critical role in antigen presentation of both viral antigens (7) and tumor antigens from a variety of cancers (8-10). HER2/neu is a 185-kDa transmembrane glycoprotein with tyrosine kinase activity and extensive homology to the epidermal growth factor receptor (11). HER2/neu is ubiquitously expressed in many tumors and known to be overexpressed in approximately 30-40% of all ovarian and breast cancers (12).We have shown that tumor-specific CTLs can be demonstrated in the tumor-infiltrating lymphocytes (TILs) isolated from ovarian cancers (13). We have also found that HLA-A2 presents TAA in this disease (14). The level of expression of the HER2/neu oncogene in ovarian cancer positively correlates with recognition by HLA-A2+ ovarian tumor-specific CTLs, and HLA-A2+ melanoma cells transfected with the HER2/neu gene become sensitive to ovarian cancer-specific CTLs (15). Therefore, HLA-A2-presented, HER2/neuderived antigenic peptides may be recognized by ovarian cancer-specific CTLs and, potentially, by breast cancerspecific CTLs as well.In this study, we have searched the HER2/neu sequence (16) for HLA-A2-binding peptides (17), and we have found that both ovarian and breast cancer-specific CTLs recognize a nine-amino acid peptide from the transmembrane portion of the HER2/neu protein (GP2; amino acids 654-662). This peptide is widely expressed in HER2/neu+ tumors and is capable of inducing HLA-A2-restricted, tumor-specific CTL populations in vitro. METHODSGeneration of Tumor-Specific CTLs. Tumor-specific CTLs were generated from fresh tumor specimens obtained through the Departments of Surgery, Gynecologic Oncology, and Pathology at Brigham and Women's Hospital (BWH) and Beth Israel Hospital in Boston, under approval of the Institutional Review Boards. Solid tumor specimens were processed as previously described (14). Briefly, specimens were minced manually and enzymatically digested, and the lymphocytes and tumor cells were separated by centrifugation over discontinuous Ficoll (Organon Teknika-Cappel) gradients. TILs were suspended in RPMI-1640 medium (BioWhittaker) supplemented with 10% fetal calf serum (BioWhittaker) and antibiotics. Cultures were suspended at 5 x 105 cells per ml on solid-phase, anti-CD3 polystyrene plates (Orthoclone OKT3, Ortho Pharmaceuticals) for 48 h. T cells were then mainta...

Modification of the HER2NEU‐derived tumor antigen GP2 improves induction of GP2‐reactive cytotoxic T lymphocytes

“…31 Our earlier studies showed that GP2-CTL could be generated from ovarian and breast cancer patients. 6,8 In our current study, a strong GP2-specific CTL reaction was elicited by modified GP2-pulsed DC from PBL from healthy individuals. Thus, GP2-specific precursor CTL may be present in normal donors and cancer patients at varying frequencies and modification of GP2 could efficiently induce GP2 specific CTL from those precursors.…”

Results of the first phase 1 clinical trial of the HER‐2/neu peptide (GP2) vaccine in disease‐free breast cancer patients

“…GP2, initially described by Peoples et al, is a 9 amino acid peptide derived from the transmembrane portion of the HER-2/neu protein. 7 The peptide was isolated using tumor-associated lymphocytes from patients with breast and ovarian cancer, and later found to be shared among several epithelial malignancies including nonsmall cell lung cancer and pancreatic cancer. [15][16][17][18] GP2 differs from E75 in that it has been termed a subdominant epitope of the HER-2/neu protein because of its relatively lower binding affinity for the HLA-A2 molecule.…”

“…[15][16][17][18] GP2 differs from E75 in that it has been termed a subdominant epitope of the HER-2/neu protein because of its relatively lower binding affinity for the HLA-A2 molecule. 7,19 E75, conversely, has a high affinity for HLA-A2 and has been identified as the immunodominant HER-2/neu epitope. 6 Interestingly, both peptides are capable of inducing similar percentages of peptide-specific CTLs, despite GP2 having a substantially lower binding affinity compared with E75.…”

“…6,7 E75 is derived from the extracellular domain of the HER-2/neu protein (369-377:KIFGSLAFL), whereas GP2 is derived from the transmembrane portion of the HER-2/ neu protein (654-662:IISAVVGIL). E75 has a high binding affinity for the HLA-A2 molecule and is considered the immunodominant peptide of the HER-2/neu protein, whereas GP2 has a low binding affinity and is considered a subdominant epitope.…”

Expression and immunogenicity of a tumor‐associated antigen, 90K/Mac‐2 binding protein, in lung carcinoma

“…[1][2][3][4][5][6][7][8][9] Some TAAs had been established as targets for cancer immunotherapy in several clinical trials. 10,11 Conversely, in lung carcinoma, no available cancer immunotherapy has been established.…”