Antitumor monoclonal antibodies enhance cross-presentation ofcCellular antigens and the generation of myeloma-specific killer T cells by dendritic cells.

The mechanism of antitumor effect of monoclonal antibodies (mAbs) is not fully understood. Here we show that coating myeloma cells with anti-syndecan-1 antibody promotes cross-presentation of cellular antigens by dendritic cells (DCs) to autologous T cells from healthy donors. The tumor cells treated with anti-syndecan-1 or isotype-matched control antibody were fed to HLA-mismatched monocyte-derived immature DCs. Tumor cell-loaded mature DCs induced a strong CD8(+) T cell response that was specific for the cancer-testis (C-T) antigens expressed in the tumor. The CD8(+) T cells killed peptide-pulsed targets, as well as myeloma tumor cells. Importantly, mAbs-coated tumor-loaded DCs were consistently superior to DCs loaded with peptides or dying cells for eliciting tumor-specific killer T cells. This enhanced cross-presentation was not due to enhanced tumor cell uptake or to DC maturation. When mixtures of NY-Eso-1-positive and -negative myeloma cells were captured by DCs, the anti-syndecan-1 antibody had to be on the NY-Eso-1-positive cells to elicit NY-Eso-1-specific response. Cross-presentation was inhibited by pretreatment of DCs with Fc gamma receptor blocking antibodies. Targeting of mAb-coated tumors to DCs may contribute to the efficacy of tumor-reactive mAb and offers a new strategy for immunotherapy.

Cancer-testis genes are coordinately expressed and are markers of poor outcome in non-small cell lung cancer.

PURPOSE: Cancer-testis genes mapping to the X chromosome have common expression patterns and show similar responses to modulators of epigenetic mechanisms. We asked whether cancer-testis gene expression occurred coordinately, and whether it correlated with variables of disease and clinical outcome of non-small cell lung cancer (NSCLC). EXPERIMENTAL DESIGN: Tumors from 523 NSCLC patients undergoing surgery were evaluated for the expression of nine cancer-testis genes (NY-ESO-1, LAGE-1, MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, CT7/MAGE-C1, SSX2, and SSX4) by semiquantitative PCR. Clinical data available for 447 patients were used to correlate cancer-testis expression to variables of disease and clinical outcome. RESULTS: At least one cancer-testis gene was expressed by 90% of squamous carcinoma, 62% of bronchioloalveolar cancer, and 67% of adenocarcinoma samples. Statistically significant coexpression was observed for 34 of the 36 possible cancer-testis combinations. Cancer-testis gene expression, either cumulatively or individually, showed significant associations with male sex, smoking history, advanced tumor, nodal and pathologic stages, pleural invasion, and the absence of ground glass opacity. Cox regression analysis revealed the expression of NY-ESO-1 and MAGE-A3 as markers of poor prognosis, independent of confounding variables for adenocarcinoma of the lung. CONCLUSIONS: Cancer-testis genes are coordinately expressed in NSCLC, and their expression is associated with advanced disease and poor outcome.

NY-ESO-1 and LAGE-1 cancer-testis antigens are potential targets for immunotherapy in epithelial ovarian cancer.

Cancer-testis (CT) antigens are expressed in a variety of cancers, but not in normal adult tissues, except for germ cells of the testis, and hence appear to be ideal targets for immunotherapy. In an effort to examine the potential of NY-ESO-1 and LAGE-1 CT antigens for immunotherapy in epithelial ovarian cancer (EOC), we examined the expression of these antigens by reverse transcription-PCR (RT-PCR) and immunohistochemistry (IHC) in a large panel of EOC tissues and cell lines. Sera from a subgroup of the patients were tested for NY-ESO-1/LAGE-1 antibody by ELISA. The data indicated that four ovarian cancer cell lines were positive for one or both CT antigens. Expression of NY-ESO-1 in EOC was demonstrated by RT-PCR and/or IHC in 82 of 190 (43%) specimens. NY-ESO-1 expression by IHC ranged from homogeneous to heterogeneous pattern. LAGE-1 mRNA expression was present in 22 of 107 (21%) tumor tissues. Overall, the expression of either NY-ESO-1 or LAGE-1 mRNA was present in 42 of 107 (40%) EOC specimens and coexpression of both antigens was demonstrated in 11% of specimens. Antibody to NY-ESO-1/LAGE-1 was present in 11 of 37 (30%) patients whose tumors expressed either NY-ESO-1 or LAGE-1. Detectable antibodies were present for up to 3 years after initial diagnosis. Although there was no statistically significant relation between expression of NY-ESO-1/LAGE-1 antigen and survival, the data showed aberrant expression of NY-ESO-1 and LAGE-1 by IHC/RT-PCR in a significant proportion of EOC patients. These findings indicate that NY-ESO-1 and LAGE-1 are attractive targets for antigen-specific immunotherapy in EOC.

NY-ESO-1 expression and immunogenicity in malignant and benign breast tumors.

NY-ESO-1 is a cancer/testis antigen expressed in normal adult tissues solely in the testicular germ cells of normal adults and in various cancers. It induces specific humoral and cellular immunity in patients with NY-ESO-1-expressing cancer. The aim of this study was to determine the frequency of NY-ESO-1 mRNA and protein expression in malignant and benign breast tumors. NY-ESO-1 mRNA expression was detected by conventional reverse transcription-PCR and real-time PCR, and that of the protein expression by immunohistochemistry and Western blot analysis. Expression of NY-ESO-1 mRNA was detected in 37 of 88 (42%) cancer specimens, whereas that of the NY-ESO-1 protein was detected only in 1 mRNA-positive specimen. In the latter case, expression level of NY-ESO-1 mRNA relative to that in the testis was relatively high (75% of testicular expression) and to the other among breast cancer specimens. In benign breast lesions, 21 of 31 (68%) specimens expressed low levels of NY-ESO-1 mRNA. In 1 case of fibroadenoma, NY-ESO-1 mRNA was 8% of the testicular level, and protein was detected by Western blot analysis. Only 1 breast cancer patient had detectable antibody at time of surgery, which disappeared within 2 years. Tumor specimen from this patient was both NY-ESO-1 mRNA and protein positive, and NY-ESO-1-specific CD8 T cells were detected in this patient by IFN-gamma enzyme-linked immunospot assay using NY-ESO-1 recombinant adeno and vaccinia virus. A higher rate of NY-ESO-1 expression was noted in breast cancer with high histological grade and negative hormone receptor status, suggesting NY-ESO-1 as a potential tumor antigen for immunotherapy in patients with breast cancer and poor prognosis.

Identification of the gonad-specific anion transporter SLCO6A1 as a cancer/testis (CT) antigen expressed in human lung cancer.

Serological analysis of recombinant cDNA expression libraries (SEREX) has led to the identification of many of the antigens recognized by the immune system of cancer patients, which are collectively referred to as the cancer immunome. We used SEREX to screen a testicular cDNA expression library with sera obtained from non-small cell lung cancer patients and isolated cDNA clones for 82 antigens. These included a total of 31 antigens previously identified by SEREX, and 51 that did not match entries in the Cancer Immunome Database and were considered newly identified antigens. Overall, the antigens comprised 62 known proteins and 20 uncharacterized gene products. Six antigens (NY-TLU-6, -37, -39, -57, -70, -75) were identified as putative cell surface proteins that are potential targets for monoclonal antibody-based immunotherapy. Of these, the gonad-specific anion transport protein SLCO6A1 (NY-TLU-57) was shown to be tissue-restricted. RT-PCR showed it to be expressed strongly only in normal testis, and weakly in spleen, brain, fetal brain, and placenta. In addition, NY-TLU-57 mRNA was found in lung tumor samples (5/10) and lung cancer cell lines (6/11), as well as bladder (5/12) and esophageal (5/12) tumor samples. These data suggest that SLCO6A1 is a putative cancer/testis (CT) cell surface antigen of potential utility as a target for antibody-based therapy for a variety of tumor types. The analysis also permits us to estimate the eventual size of the SEREX-defined cancer immunome at around 4000 genes. This emphasizes the importance of continued SEREX screening to define the cancer immunome.

Frequency of NY-ESO-1 and LAGE-1 expression in bladder cancer and evidence of a new NY-ESO-1 T-cell epitope in a patient with bladder cancer.

Cancer-testis (CT) antigens are ideal vaccine targets since their expression is restricted in adult tissues to testicular germ cells and a subset of cancers. The frequency of expression in transitional cell carcinomas (TCCs) of NY-ESO-1, the most immunogenic CT antigen to date, and its closely related gene LAGE-1 was studied. NY-ESO-1 and LAGE-1 antigen expression were found to occur frequently in high-grade TCC tumors. On an MSKCC IRB-approved protocol, 68 patient specimens were collected prospectively at the time of transurethral resection or cystectomy, of which 43 were read pathologically as high-grade tumors (pCIS, pTaG3, pT1, pT2, pT3, and pT4), 8 as low-grade tumors (pTaG1, pTaG2), and 17 as disease-free samples. These 68 samples were analyzed by immunohistochemistry (IHC) and/or RT-PCR. There were also an additional 53 paraffin-embedded specimens studied retrospectively by IHC, of which 39 were high-grade tumors and 14 were low-grade tumors. Cumulatively, our data indicate that NY-ESO-1 and/or LAGE-1 are expressed in 39/82 (48%) high-grade TCC and 3/22 (14%) low-grade TCC samples when analyzed by RT-PCR and/or IHC. Immunological assessment of these patients' sera identified one patient, whose tumor homogeneously expressed NY-ESO-1, which had detectable antibodies against NY-ESO-1 and LAGE-1. Further analysis of this patient, who remains clinically without evidence of disease 24 months after cystectomy for high-grade pT4 disease, revealed T-cell immunity against NY-ESO-1. This patient's T-cell response was determined to be specific for a new NY-ESO-1 epitope, p94-102, in the context of HLA-B35.

SSX antigens as tumor vaccine targets in human sarcoma.

The efficacy of current standard therapies for the treatment of sarcoma remains limited. With the aim of identifying target antigens relevant to the development of vaccine-based immunotherapy of sarcoma, we have addressed the relevance of tumor-specific antigens encoded by genes belonging to the SSX family as vaccine targets in sarcoma tumors. Expression of SSX-1 to -5 was analyzed in a collection of sarcoma tumors of diverse histological subtypes and in sarcoma cell lines. We found expression of at least one SSX-encoded antigen in 42% of sarcoma tumors, including 5 of 7 different histological subtypes, and in 50% of sarcoma cell lines. SSX-1 was the most frequently expressed family member, followed by SSX-4, -2 and -5. Expression of SSX-3 was detected in only one sample. Importantly, most SSX positive samples co-expressed more than one family member. In addition, assessment of CD8+ T cell recognition of HLA-A2+ SSX-2+ sarcoma cells showed that the latter were efficiently recognized and lysed by SSX-2-specific CTLs. The results of this study indicate that SSX antigens are relevant targets for the development of vaccine-based immunotherapy of sarcoma and encourage the start of vaccination trials using SSX-derived immunogens in sarcoma patients.

The cancer-testis antigens CT7 (MAGE-C1) and MAGE-A3/6 are commonly expressed in multiple myeloma and correlate with plasma-cell proliferation.

Multiple myeloma is a malignancy of plasma cells. Vaccine immunotherapy is among the novel therapeutic strategies under investigation for this disease. To identify myeloma-associated antigens as potential targets for vaccine immunotherapy, we surveyed a comprehensive panel of bone marrow specimens from patients with monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma for expression of cancer-testis (CT) antigens. Immunohistochemistry (IHC) demonstrated that 82% of stage-III myeloma specimens expressed the CT antigen CT7 (also known as melanoma antigen C1 [MAGE-C1]) and 70% expressed MAGE-A3/6. Messenger RNA for CT7 and MAGE-A family members was detected in 87% and 100% of stage-III samples, respectively. CT7 protein expression increased with advanced stage of disease. Higher levels of CT7 and MAGE-A3/6 proteins also correlated with elevated plasma-cell proliferation. These results show that CT7 and MAGE-A3/6 are promising myeloma-associated antigens for application in vaccine immunotherapy. Furthermore, the common expression and correlation with proliferation suggest a possible pathogenic role for these proteins in myeloma.

Targeted bioactivity of membrane-anchored TNF by an antibody-derived TNF fusion protein.

We describe the generation and characterization of a fusion protein consisting of a humanized anti-fibroblast-activating protein (anti-FAP) Ab and human TNF replacing the IgG1 CH2/CH3 Fc domain. The construct was generated by recombinant DNA technology and preserved its IgG1-derived dimeric structure with the TNF molecule linked as a dimer. Expression in CHO cells was optimized in serum-free medium under GMP conditions to achieve production levels up to 15 mg/liter. Recognition of the FAP Ag by the construct was as good as that by the parental anti-FAP Ab. TNF signaling was induce able via both TNF receptor types. When acting in solution, the Ab-linked TNF dimer exhibited a 10- to 20-fold lower activity compared with recombinant trimeric TNF. However, after binding to FAP-expressing cells, immobilized anti-FAP-TNF dimer was equivalent to membrane-anchored TNF with regard to bioactivity. Amplification of TNF-related pathways by mimicking the membrane-integrated TNF signaling was detectable in various systems, such as apoptosis induction or tissue factor production. The difference in TNF receptor type 1 and 2 signaling by the anti-FAP-TNF construct correlated well with its Ag-bound or -soluble status. Translating the approach into a xenograft animal model (BALB/c nu/nu mice), we demonstrated low toxicity with measurable antitumor efficacy for the TNF fusion protein after i.v. application. Immunohistochemical analysis of tumor sections showed restricted TNF-mediated macrophage recruitment to the targeted tissue in a time- and dose-dependent manner. These data warrant transfer of the anti-FAP-TNF immunocytokine into clinical trials for the treatment of FAP-positive tumors.

Immunomic analysis of human sarcoma.

The screening of cDNA expression libraries from human tumors with serum antibody (SEREX) has proven to be a powerful method for identifying the repertoire of tumor antigens recognized by the immune system of cancer patients, referred to as the cancer immunome. In this regard, cancer/testis (CT) antigens are of particular interest because of their immunogenicity and restricted expression patterns. Synoivial sarcomas are striking with regard to CT antigen expression, with >80% of specimens homogeneously expressing NY-ESO-1 and MAGE-A3. In the present study, 54 sarcoma patients were tested for serum antibodies to NY-ESO-1, SSX2, MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, CT7, and CT10. Two patients had detectable antibodies to CT antigens, and this seroreactivity was restricted to NY-ESO-1. Thus, although highly expressed in sarcoma, CT antigens do not induce frequent humoral immune responses in sarcoma patients. Sera from these two patients were used to immunoscreen cDNA libraries from two synovial sarcoma cell lines and normal testis, resulting in the identification of 113 distinct antigens. Thirty-nine antigens were previously identified by SEREX analysis of other tumor types, and 2339 antigens (59%) had a serological profile that was not restricted to cancer patients, indicating that only a proportion of SEREX-defined antigens are cancer-related. A novel CT antigen, NY-SAR-35, mapping to chromosome Xq28 was identified among the cancer-related antigens, and encodes a putative extracellular protein. In addition to testis-restricted expression, NY-SAR-35 mRNA was expressed in sarcoma, melanoma, esophageal cancer, lung cancer and breast cancer. NY-SAR-35 is therefore a potential target for cancer vaccines and monoclonal antibody-based immunotherapies.

CT7 (MAGE-C1) antigen expression in normal and neoplastic tissues.

CT7 (MAGE-C1) is a member of the cancer testis (CT) antigen family. The present study describes the generation of CT7-33, a monoclonal antibody (MAb) to CT7, and the preliminary protein expression analysis of CT7 in normal tissues and in a limited number of neoplastic lesions. CT7-33 was effective in frozen as well as formalin-fixed, paraffin-embedded tissues, and immunohistochemistry/reverse transcriptase polymerase chain reaction (RT-PCR) co-typing demonstrated antibody specificity. CT7-33 immunoreactivity in normal adult tissues is restricted to testicular germ cells. In neoplastic lesions, CT7-33 immunostaining is confined to tumor cells, and the frequency of CT7 protein expression mostly parallels previous mRNA analyses. Whereas colorectal and renal cell carcinomas, as well as sarcomas, exhibit poor or no CT7-33 staining, carcinomas of the mammary gland and ovary, nonsmall cell lung carcinoma and metastatic melanomas exhibit a high incidence of CT7 protein expression. However, as seen in previous analyses of other CT antigens, the expression pattern is mostly heterogeneous, and tumors with more than 50% of tumor staining are only infrequently encountered. In summary, our study presents a new serologic reagent for the analysis of CT7 on a protein level and confirms what is known with regard to the expression pattern of other CT antigens in tumors: frequent heterogeneity of antigen expression.

Identification of cancer/testis genes by database mining and mRNA expression analysis.

Cancer/testis (CT) antigens are immunogenic proteins expressed predominantly in gametogenic tissue and cancer; they are considered promising target molecules for cancer vaccines. The identification of new CT genes is essential to the development of polyvalent cancer vaccines designed to overcome tumor heterogeneity and antigen loss. In the current study, a search for new CT genes was conducted by mining the Unigene database for gene clusters that contain expressed sequence tags derived solely from both normal testis and tumor-derived cDNA libraries. This search identified 1,325 different cancer/testis-associated Unigene clusters. The mRNA expression pattern of 73 cancer/testis-associated Unigene clusters was assessed by reverse transcriptase polymerase chain reaction. Three gene products, CT15/Hs.177959, CT16/Hs.245431 and CT17/Hs.178062, were detected only in testis and in tumor tissue. CT15 is equivalent to ADAM2/fertilin-beta. CT16, an uncharacterized gene product, has homology (30-50%) to members of the GAGE gene family and is 89% identical to CT16.2/Hs.293317, indicating that CT16 and CT16.2 are members of a new GAGE gene family. The uncharacterized gene product, CT17, has homology (30%) to phospholipase A1. RT-PCR analysis showed that CT15 is expressed exclusively in renal cancer, whereas CT16 and CT17 are expressed in a range of human cancers. Real-time RT-PCR analysis of newly defined CT genes and the prototype CT antigens, MAGE-3 and NY-ESO-1, revealed low levels (less than 3% of the level detected in testis) of CT15, CT16 and NY-ESO-1 in a limited range of normal, non-gametogenic tissues. This study demonstrates the merits of database mining with respect to the identification of tissue-restricted gene products expressed in cancer.

Vaccine-induced CD4+ T cell responses to MAGE-3 protein in lung cancer patients.

MAGE-3 is the most commonly expressed cancer testis Ag and thus represents a prime target for cancer vaccines, despite infrequent natural occurrence of MAGE-3-specific immune responses in vivo. We report in this study the successful induction of Ab, CD8(+), and CD4(+) T cells in nonsmall cell lung cancer patients vaccinated with MAGE-3 recombinant protein. Two cohorts were analyzed: one receiving MAGE-3 protein alone, and one receiving MAGE-3 protein with adjuvant AS02B. Of nine patients in the first cohort, three developed marginal Ab titers and another one had a CD8(+) T cell response to HLA-A2-restricted peptide MAGE-3 271-279. In contrast, of eight patients from the second cohort vaccinated with MAGE-3 protein and adjuvant, seven developed high-titered Abs to MAGE-3, and four had a strong concomitant CD4(+) T cell response to HLA-DP4-restricted peptide 243-258. One patient simultaneously developed CD8(+) T cells to HLA-A1-restricted peptide 168-176. The novel monitoring methodology used in this MAGE-3 study establishes that protein vaccination induces clear CD4(+) T cell responses that correlate with Ab production. This development provides the framework for further evaluating integrated immune responses in vaccine settings and for optimizing these responses for clinical benefit.