Expression of MAGE-1 and -3 genes and gene products in human hepatocellular carcinoma

HCA587 Protein Vaccine Induces Specific Antitumor Immunity Mediated by CD4+ T-cells Expressing Granzyme B in a Mouse Model of Melanoma

BACKGROUND

The antigen HCA587 (also known as MAGE-C2), which is considered a cancer-testis antigen, exhibits upregulated expression in a wide range of malignant tumors with unique immunological properties, and may thus serve as a promising target for tumor immunotherapy.

OBJECTIVE

The study aimed to explore the antitumor effect of the HCA587 protein vaccine and the response of humoral and cell-mediated immunity.

METHODS

The HCA587 protein vaccine was formulated with adjuvants CpG and ISCOM. B16 melanoma cells were subcutaneously inoculated to C57BL/6 mice, followed by treatment with HCA587 protein vaccine subcutaneously. Mouse survival was monitored daily, and tumor volume was measured every 2 to 3 days. The tumor sizes, survival time and immune cells in tumor tissues were detected. And the vital immune cell subset and effector molecules were explored.

RESULTS

After treatment with HCA587 protein vaccine, the vaccination elicited significant immune responses, which delayed tumor growth and improved animal survival. The vaccination increased the proportion of CD4⁺ T cells expressing IFN-γ and granzyme B in tumor tissues. The depletion of CD4⁺T cells resulted in an almost complete abrogation of the antitumor effect of the vaccination, suggesting that the antitumor efficacy was mediated by CD4⁺ T cells. In addition, knockout of IFN-γ resulted in a decrease in granzyme B levels, which were secreted by CD4⁺ T cells, and the antitumor effect was also significantly attenuated.

CONCLUSION

The HCA587 protein vaccine may increase the levels of granzyme B expressed by CD4⁺ T cells, and this increase is dependent on IFN-γ, and the vaccine resulted in a specific tumor immune response and subsequent eradication of the tumor.

Immunological and functional aspects of MAGEA3 cancer/testis antigen

Identification of ectopic gene activation in cancer cells serves as a basis for both gene signature-guided tumor targeting and unearthing of oncogenic mechanisms to expand the understanding of tumor biology/oncogenic process. Proteins expressed only in germ cells of testis and/or placenta (immunoprivileged organs) and in malignancies are called cancer testis antigens; they are antigenic because of the lack of antigen presentation by those specific cell types (germ cells), which limits the exposure of the proteins to the immune cells. Since the Cancer Testis Antigens (CTAs) are immunogenic and expressed in a wide variety of cancer types, CT antigens have become interesting target for immunotherapy against cancer. Among CT antigens MAGEA family is reported to have 12 members (MAGEA1 to MAGEA12). The current review highlights the studies on MAGEA3 which is a CT antigen and reported in almost all types of cancer. MAGEA3 is well tried for cancer immunotherapy. Recent advances on its functional and immunological aspect warranted much deliberation on effective therapeutic approach, thus making it a more interesting target for cancer therapy.

In vivo enhancement of the MAGE-specific cellular immune response by a recombinant MAGE1-MAGE3-TBHSP70 tumor vaccine

Background

Since cytotoxic T cell (CTL) response is the major cellular type in attacking tumor cells, most immunotherapy targets to manipulate the CTL response. Immunotherapies targeting melanoma-specific antigens (MAGEs), a group of tumor-specific shared antigen, have shown to be promising. Our previous study has shown that MAGE1/TBHSP70 and MAGE3/TBHSP70 could induce a robust immune response against B-16 melanoma cells in C57BL/6 mice. In this study, we used an animal model to further demonstrate MAGEs as a potential immunotherapy target for tumorigenesis in vivo.

Methods

In the current study, we developed a MAGE1/MAGE3/TBHSP70 recombinant protein vaccine and evaluated its protective efficacy against tumor development by challenge vaccine-immunized mice with MAGE-expressing human tumor cell lines in a Hu-PBL-SCID mouse model. The cellular immune reactions were monitored by ELISPOT and cytotoxicity assays.

Results

Splenocytes isolated from vaccine-immunized mice presented potent cytokine secretion capacity and CTL-specific cytotoxic. Vaccine-immunized mice had a significant tumor regression and prolonged survival compared with controls (both p < 0.05). In vitro, rMAGE1-MAGE3-TBHSP70 showed a potent tumor-antigen-specific immune response in both hepatocellular carcinoma and pulmonary carcinoma cell lines.

Conclusion

This newly-developed recombinant protein vaccine may serve as a new immunotherapy for cancer.

MAGE-A3: an immunogenic target used in clinical practice

Melanoma antigen family A, 3 (MAGE-A3) is a cancer-testis antigen whose expression has been demonstrated in a wide array of malignancies including melanoma, brain, breast, lung and ovarian cancer. In addition, its ability to elicit spontaneous humoral and cellular immune responses has been shown in cancer patients. As antigen-specific immune responses can be stimulated by immunization with MAGE-A3, several clinical trials have used MAGE-A3 vaccines to observe clinical responses. The frequent expressions of this antigen in various tumors and its immunogenicity in cancer patients have led to application of this antigen in cancer immunotherapy. However, the results of recent clinical trials indicate that there is a need for research in the vaccine design, adjuvant selection as well as patient selection criteria.

Over-Expression of the Testis-Specific GeneTSGA10in Cancers and Its Immunogenicity

The TSGA10 gene was originally isolated in normal testis by differential mRNA display. TSGA10 is located on chromosome 2q11.2 and consists of 19 exons extending over 3 kb. TSGA10 mRNA expression was investigated in normal and malignant tissues using quantitative real-time RT-PCR. It was predominantly expressed in the testis in adult normal tissues. In malignant tissues, TSGA10 was over-expressed in 4 of 20 hepatocellular carcinomas (HCC), 1 of 20 colon cancers, 7 of 20 ovarian cancers, 3 of 20 prostate cancers, 1 of 21 malignant melanomas, and 8 of 21 bladder cancers. Serological analysis revealed that 3 out of 346 patients with various types of cancer possessed antibody against recombinant TSGA10 protein. They included 2 patients with hepatocellular carcinoma and a patient with malignant melanoma.

Phase I/II study of immunotherapy using tumor antigen-pulsed dendritic cells in patients with hepatocellular carcinoma

Dendritic cells (DCs) are increasingly used as adjuvants for vaccination strategies; however, there has been very little development in DC vaccines for patients with hepatocellular carcinoma (HCC). In this study, we assessed the safety, feasibility and efficacy of a multiple tumor-associated antigen (TAA)-pulsed DC vaccine in 5 patients with advanced HCC. DCs were generated by culturing blood monocytes in the presence of granulocyte macrophage-colony stimulating factor and interleukin-4 for 5 days. The DC vaccine was prepared by pulsing DCs with cytoplasmic transduction peptide-attached α-fetoprotein, glypican-3 and MAGE-1 recombinant fusion proteins and cultivating them in the presence of maturation cocktail. DCs were injected subcutaneously near the inguinal lymph nodes, followed by topical application of toll-like receptor-7 agonist around the injection site. We showed that our DC vaccine was safe and well-tolerated over 6 vaccinations in 5 patients. All 5 patients showed T cell responses against TAAs. Clinical benefit was observed in one of the 5 patients. In conclusion, the feasibility, safety and immune activity of DCs pulsed with TAAs were confirmed in HCC patients. However, clinical response was detected only in one patient. Future trials may consider applying this therapy in a less advanced stage to obtain better clinical responses.

Induction of HCA587-specific antitumor immunity with HCA587 protein formulated with CpG and ISCOM in mice

HCA587 (also known as MAGE-C2) is a “cancer-testis” antigen highly expressed in a number of malignancies with unique immunological properties, making it a promising target for tumor immunotherapy. In this report, we demonstrated that HCA587 protein, when formulated with adjuvants CpG–containing oligodeoxynucleotides (CpG ODN) and ISCOM, was capable of inducing a potent cellular and humoral immune response as indicated by the presence of a large number of HCA587-specific, IFN-γ-producing CD4⁺ T cells and high levels of HCA587-specific antibodies. More importantly, vaccination with HCA587 conferred protection against challenge with HCA587-expressing B16 melanoma in prophylactic and therapeutic settings. In analysis of the mechanisms underlying the protective effect, we showed that the vaccination was followed by enhanced accumulation of tumor-infiltrating lymphocytes (TILs) with enrichment of conventional CD4⁺ T cells but reduced representation of Treg cells. Further, the antitumor effect was largely abrogated in mice either depleted of CD4⁺ T cells or deficient for IFN-γ. These results indicate that HCA587 protein vaccine possesses evident antitumor activity in a mouse model and holds promise for treatment of human cancers.

The significance of MAGED4 expression in non-small cell lung cancer as analyzed by real-time fluorescence quantitative PCR

The aim of this study was to detect differences in the expression levels of melanoma-associated antigen D4 (MAGED4) mRNA between non-small cell lung cancer (NSCLC) tissues and normal tissues, and to compare differences in the expression levels of MAGED4 in tumor patients. Patients were grouped according to age, gender, smoking history, tumor size, pathological classification, degree of lung cancer cell differentiation and presence of lymph node metastasis. The expression levels of MAGED4 were detected using real-time fluorescence quantitative PCR. MAGED4 expression was higher in squamous cell carcinomas compared to adenocarcinomas (P<0.05), in poorly differentiated tissues compared to well-differentiated tissues (P<0.05), and in patients with lymph node metastasis compared to patients without lymph node metastasis (P<0.05). MAGED4 may be used as a specific antigen for NSCLC to influence the improvement of diagnosis, prognosis and immunological therapy outcomes in lung cancer patients.

MAGE-4 gene m-RNA and TGF in blood as potential biochemical markers for HCC in HCV-infected patients

Progression from chronic hepatitis C virus infection to cirrhosis then to hepatocellular carcinoma usually results in some protein changes in peripheral blood. We evaluated MAGE-4 mRNA, TGFβ1 and AFP in peripheral blood as potential biochemical markers for diagnosis and prognosis of some complications of HCV infection. MAGE-4 mRNA in blood by reverse transcription polymerase chain reaction, serum TGF-Β1 and AFP by ELISA was assayed in seventy-five individuals who were classified into five groups: group I (control) comprised fifteen apparently healthy volunteers, group II involved fifteen HCV-infected patients without cirrhosis, group III involved fifteen HCV fifteen HCV-infected patients with cirrhosis, group IV included fifteen HCV-infected patients with cirrhosis and early stage HCC, and group V included fifteen HCV cirrhotic patients and late-stage HCC. We found that the frequency of positivity of MAGE-4 among the late hepatoma group was 40 %, while in the early hepatoma group the positivity was 6.7 %. The results for TGF-Β1 revealed a significant increase in serum TGF-Β1 in groups IV and V as compared to control, II, III groups. The obtained results of AFP showed a significant positive increase in serum AFP in groups IV and V when compared to groups II and III. Detection of MAGE-4 transcripts in blood, especially with follow-up survey, may help to predict the prognosis and monitoring of the response to the therapy, and serum TGF-Β1 level in HCC patients is directly correlated with metastasis and recurrence of tumors and increases gradually with the progression of HCC.

MAGE-3 and MAGE-4 genes as possible markers for early detection of metastases in hepatitis C virus Egyptian patients complicated by hepatocellular carcinoma

The dissemination of hepatocellular carcinoma (HCC) cells into the circulation plays a critical role in post-operative recurrence and metastasis. Early detection of metastatic tumor cells is critical to identify HCC patients at high risk of relapse. MAGE-3 and -4 genes were evaluated by reverse transcription polymerase chain reaction for the possibility of using them as new markers for early detection of metastases in 160 chronic HCV Egyptian patients, 115 of them were complicated with HCC. The expressions of MAGE-3 and MAGE-4 mRNA in peripheral blood of patients with metastatic HCC were 36 and 52%, respectively. While the expressions of MAGE-3 and MAGE-4 mRNA in peripheral blood of patients with localized HCC were 12.5 and 15%, respectively. Moreover, at least one type of mRNA was found in the peripheral blood of 68% of the metastatic HCC patients and in 20% of the localized HCC patients. While neither the controls nor the cirrhotic patients show expression of MAGE-4 mRNA in their peripheral blood. MAGE-3 and MAGE-4 may be a promising diagnostic tool for monitoring the prognosis of HCC patients and early detection of occult hematogenous metastasis of HCC.

Strong CD8(+) T-cell responses against tumor-associated antigens prolong the recurrence-free interval after tumor treatment in patients with hepatocellular carcinoma

AIM

We investigated whether tumor-specific CD8(+) T-cell responses affect tumor-free survival as well as the relationship between CD8(+) T-cell responses against tumor-associated antigens (TAAs) and the clinical course after tumor treatment in patients with hepatocellular carcinoma (HCC).

METHODS

Twenty patients with HCC that were treated by radiofrequency ablation or trans-catheter chemo-embolization (TACE) and in whom HCC was undetectable by ultrasonography, CT, and/or MRI 1 month after treatment were enrolled in the study. Before and after treatment for HCC, analyses of TAA (glypican-3, NY-ESO-1, and MAGE-1)-specific CD8(+) T-cell responses were evaluated with an interferon-gamma enzyme-linked immunospot (ELISpot) assay using peripheral CD8(+) T-cells, monocytes, and 104 types of 20-mer synthetic peptide overlapping by 10 residues and spanning the entirety of the 3 TAAs.

RESULTS

Sixteen out of 20 patients (80%) showed a positive response (> or = 10 TAA-specific cells/10(5) CD8(+) T-cells) before or after treatment. When we performed univariate analysis of prognostic factors for the tumor-free period in the 20 patients, platelet count, prothrombin time, and the number of TAA-specific CD8(+) T-cells after treatment were significant factors (P = 0.027, 0.030, and 0.004, respectively). In multivariate analysis, the magnitude of the TAA-specific CD8(+) T-cell response (> or = 40 TAA-specific cells/10(5) CD8(+) T-cells) was the only significant prognostic factor for a prolonged tumor-free interval (hazard ratio 0.342, P = 0.022).

CONCLUSIONS

Our results suggest that strong TAA-specific CD8(+) T-cell responses suppress the recurrence of HCC. Immunotherapy to induce TAA-specific cytotoxic T lymphocytes by means such as the use of peptide vaccines should be considered for clinical application in patients with HCC after local therapy.

Expression and significance of cancer testis antigens in primary mucosal melanoma of the head and neck

BACKGROUND

Cancer testis antigens (CTAs) are T-cell-defined tumor-associated antigens encoded by the genes and gene families such as MAGE, NY-ESO-1, and others. Their expression in a wide variety of malignant neoplasms but absence in all normal adult tissue except testicular germ cells makes them attractive targets for immunotherapy of cancer. Primary mucosal melanomas of the head and neck (HNMM) are rare aggressive malignant tumors that are usually difficult to treat. CTAs may provide useful targets for therapy; however, their expression in HNMM is not known.

METHODS

We analyzed 40 initial, 15 recurrent, and 15 metastatic HNMM to nonmucosal locations from 64 patients (oral, n = 30; sinonasal, n = 34). Immunohistochemistry was performed on archival tissue with monoclonal antibodies 57B, CT7-33, and ES121 to the following CTAs: MAGE-A4, CT7 (MAGE-C1), and NY-ESO-1, respectively.

RESULTS

CT7, MAGE-A4, and NY-ESO-1 expression was seen in 73%, 61%, and 24% of tumors, respectively, with 81% of the tumors expressing at least one of the CTAs. CT7 and MAGE-A4 were significantly more frequently expressed in tumors composed of epithelioid cells than spindle cells (p = .05). CTA expression did not correlate with disease progression, overall survival, and disease-specific survival.

CONCLUSIONS

CT7, MAGEA4, and NY-ESO-1 are frequently expressed in HNMM and may be potential targets for CTA-based immunotherapy. The expression does not seem to have prognostic significance.

mRNA expression of MAGE-A3 gene in leukemia cells

Leukemia-associated antigens such as proteins encoded by MAGE genes might provide tools for immunotherapy of leukemia. Positive and negative results of MAGE-A gene expression in hematological malignancies have been reported. This led us to study MAGE-A gene expression in human leukemias using RT-PCR. Among 115 leukemias from various subtypes, 14/34 (41.17%) AML were positive for one of the three genes analyzed (MAGE-A1 1/32; MAGE-A3 10/32; MAGE-B2 3/12). Expression was also detected in 23/76 (30.26%) B-cell ALL patients (MAGE-A1 2/53; MAGE-A3 20/53; MAGE-B2 1/32). One of these patients expressed both MAGE-A1 (weak signal) and -A3 (strong signal) genes. Other patient with CML were positive for MAGE-B2 (1/5, 20%). MAGE-A3 expression data were corroborated by real time RT-PCR through determination of MAGE-A3 transcript levels. We concluded that the MAGE-A3 gene is expressed at the mRNA level in a proportion of human leukemias.

The spontaneous CD8+ T-cell response to HLA-A2-restricted NY-ESO-1b peptide in hepatocellular carcinoma patients

PURPOSE

Hepatocellular carcinoma (HCC) can express various cancer-testis antigens including NY-ESO-1, members of the SSX family, members of the MAGE family, SCP-1, and CTP11. Immunotherapy directed against these antigens is a potential alternative treatment for HCC. To date, it remains unclear whether HCC patients have spontaneous immune responses to these tumor antigens. The objectives of this study were to measure immune responses to NY-ESO-1, a promising cancer vaccine candidate, in HCC patients using the HLA-A2-restricted NY-ESO-1b peptide (p157-165) to measure cellular responses and whole protein to measure antibody responses.

EXPERIMENTAL DESIGN

In HLA-A2(+) patients with NY-ESO-1(+) HCC, we analyzed T-cell antigen-dependent interferon (IFN)-gamma and/or Granzyme B release by enzyme-linked immunospot (ELISPOT) assay and IFN-gamma-producing intracellular cytokine flow cytometry (CytoSpot). As an assay independent of T-cell function, we performed tetramer staining. Antibodies to whole NY-ESO-1 were assayed by enzyme-linked immunosorbent assay.

RESULTS

The frequency of specific CD8(+) T-cell responses to NY-ESO-1b in 28 NY-ESO-1 mRNA(+)HLA-A2(+) HCC patients was 35.7% (10 of 28). The average magnitude of effector CD8(+) T cells was 0.3% (89 +/- 59 per 2.5 x 10(4) CD8(+) cells) and 1.2% as measured by IFN-gamma release ELISPOT and CytoSpot assays, respectively. These in vitro induced NY-ESO-1b-specific CD8(+) T cells can also recognize HepG2 cells transfected with pcDNA3.1-NY-ESO-1 in both IFN-gamma and Granzyme B ELISPOT assays. Frequencies of NY-ESO-1b-specific T cells in several patients were confirmed by tetramer staining. Nonfunctional tetramer(+)CD8(+) T cells were also present. The CD8(+) T-cell response was apparently increased in patients with late-stage HCC. A discordance between antibody and CD8(+) T-cell responses in HCC patients was observed.

CONCLUSIONS

The elevated frequency of specific CD8(+) T-cell responses to NY-ESO-1b in NY-ESO-1 mRNA(+)HLA-A2(+) HCC patients suggests that NY-ESO-1 is appropriate for use in the immunotherapy of HCC patients.

Expression of cancer-testis antigens in endometrial carcinomas using a tissue microarray

Cancer-testis (CT) antigens are expressed in a variety of malignant tumors, but in normal adult tissue, they are only expressed in testicular germ cells. Owing to this tumor-associated expression pattern, these antigens are of major interest as potential targets for immunotherapy and possibly for diagnostic purposes. This study was performed to analyze the expression of four CT antigens, NY-ESO-1, MAGE-A3, MAGE-A4, and CT7/MAGE-C1, in endometrial carcinoma using immunohistochemistry, and to correlate expression with histologic subtypes, grade, and expression of WT1 and p53. Formalin-fixed paraffin-embedded tissues of 130 endometrial carcinomas of the following types and grades were analyzed using a tissue microarray: 85 endometrioid carcinomas (FIGO grade 1, 39; grade 2, 11; and grade 3, 35), 18 papillary serous carcinomas, 12 clear cell carcinomas, 13 malignant mixed mullerian tumors, one mucinous adenocarcinoma, and one undifferentiated carcinoma. The following anti-CT monoclonal antibodies/antigens were studied by immunohistochemistry: monoclonal antibody ES121/NY-ESO-1, monoclonal antibody M3H67/MAGE-A3, monoclonal antibody 57B/MAGE-A4, and monoclonal antibody CT7-33/CT7. The CT expression data were compared to WT1 and p53 protein expression as analyzed in a previous study. Positive staining with anti-CT monoclonal antibodies was graded as follows: focal, <5% positive cells; 1+, 5-25% cells; 2+, 26-50% cells; 3+, 51-75%; and 4+, >75% cells. The 3+ and 4+ staining patterns were considered homogeneous patterns of potential clinical significance and were scored positive for statistical analysis. In low-grade tumors, the most immunoreactivity was seen with mAb M3H67 but little labeling was observed with the other monoclonal antibodies. In high-grade tumors, monoclonal antibodies M3H67 (25%), 57B (23%), and CT7-33 (20%) showed the highest reactivity, while ES121 showed the lowest immunoreactivity (6%). The staining pattern was mostly heterogeneous. Statistical significance was found solely for the correlation of monoclonal antibody 57B staining and p53 expression. No correlation was found for any anti-CT monoclonal antibody staining and clinical stage or for anti-CT staining and WT1 expression. CT antigens CT7, MAGE-A3 and MAGE-A4, but not NY-ESO-1, are expressed in high-grade endometrial carcinomas, and expression of MAGE-A4 is correlated with the presence of overexpressed p53.

Immunotherapeutic strategies for hepatocellular carcinoma

There is a continuing need for innovative, alternative therapies for hepatocellular carcinoma (HCC). Immunotherapy for cancer is attractive because of the exquisite specificity of the immune response. Activation of an HCC-specific response can be accomplished by strategies targeting tumor-associated self-antigens (for example, alpha-fetoprotein [AFP]). Gene array studies have added to the list of HCC-specific gene products that can be targeted. Alternatively, the immune response can be targeted against viral antigens in those patients infected with hepatitis B or C virus. Uncharacterized and mutated antigens can also be targeted with whole tumor cell or tumor lysate-based immunization strategies or with vectors coding for genes that make the tumor immunogenic, allowing the immune system to naturally evolve specificity against immunogenic target antigens. Strategies being investigated in animal models include increasing tumor immunogenicity by targeting cytokines or costimulatory molecules to tumor; immunization with tumor cells fused with antigen-presenting cells; adoptive transfer of viral antigen-specific T cells; and targeting AFP-expressing HCC cells by DNA, adenovirus, peptide, and dendritic cell (DC) strategies. Strategies that have been tested in human clinical trials include adoptive transfer of lymphocytes and autologous tumor-pulsed DC as well as 2 AFP-based strategies: AFP-derived peptides in Montanide and AFP peptides pulsed onto autologous DC. These trials, testing novel immune-based interventions in HCC subjects, have resulted in immunologic responses and have impacted recurrence and survival in HCC subjects.

Decreased expression of B7 costimulatory molecules and major histocompatibility complex class-I in human hepatocellular carcinoma

BACKGROUND AND AIM

We analyzed the expression of antigen-processing and antigen-presenting molecules in surgically resected fresh samples of human hepatocellular carcinoma (HCC) tissue to elucidate a mechanism of immune escape. We also examined the expression of interleukin (IL)-10 protein, which might act to downregulate expression of antigen-processing and antigen-presenting molecules.

METHODS

Twenty-eight HCC samples obtained by surgical resection were analyzed for the expression of beta2-microglobulin, heat-shock protein (HSP)-70, human leukocyte antigen (HLA) class-I, CD80 (B7-1), CD86 (B7-2) and IL-10 by immunostaining.

RESULTS

Beta2-microglobulin and HSP-70 were preserved in all samples. In contrast, the expression of HLA class-I molecules was significantly reduced according to lowering in the histological grading of tumor differentiation (P = 0.024). Furthermore, B7-1 and B7-2 expression was reduced in tumor cells compared with corresponding areas of liver tissue without malignant involvement irrespective of the histological grading of tumors (21% and 36%, respectively). Although IL-10 protein was expressed in 54% of HCC, no relationship between the expression of IL-10 and downregulation of B7-1, B7-2, and HLA class-I was evident.

CONCLUSION

These findings suggest the potential role of B7 co-stimulatory molecules and HLA class-I molecules in facilitating HCC escape from immune surveillance without the involvement of IL-10.

Ex vivo characterization of tumor-derived melanoma antigen encoding gene-specific CD8+cells in patients with hepatocellular carcinoma

BACKGROUND/AIMS

Members of the melanoma antigen encoding gene family are expressed in tumors of different histological types but not in normal tissue. For this reason, they are attractive targets for cancer immunotherapy.

METHODS

In the present study, we analyzed the expression of MAGE-1 and -3 genes in the hepatocellular carcinoma (HCC) tissue as well as frequency, phenotype and function of circulating and tumor infiltrating CD8+ cells specific for HLA-A1 and -A2 restricted epitopes of MAGE-1 and -3.

RESULTS

Our study shows for the first time the presence of MAGE/tetramer+ CD8 cells in the tumor tissue of patients with HCC. These cells are able to recognize the MAGE-1 sequence 161-169 and the MAGE-3 sequence 271-279. In a patient with a particularly high frequency of MAGE-1 sequence 161-169-specific T cells, phenotypic and functional analysis was performed showing a phenotype of recently-primed CD8 cells (CD28+CD27+CD45RA-CCR7).

CONCLUSIONS

The observation of a spontaneous in vivo priming of a MAGE-specific T cell response in patients with HCC and the high frequency of MAGE antigens expression in this tumor, makes this antigen a potential candidate for a MAGE-specific immunotherapy in hepatocellular carcinoma.

Identification of the antigens predominantly reacted with serum from patients with hepatocellular carcinoma

BACKGROUND

To identify antigens specifically recognized by the immune surveillance system in patients with hepatocellular carcinoma (HCC), the authors examined two complementary DNA (cDNA) libraries of moderately differentiated HCC by serologic analysis of recombinant cDNA expression libraries (SEREX).

METHODS

The libraries were screened with autologous patients' sera, and sequences of the reacted clones were determined. To study the immunoreactivity of the antigens, sera from 20 patients with HCC, from 20 healthy volunteers, and from 16 patients with chronic viral hepatitis were examined.

RESULTS

Twenty-seven antigens were identified. They included SART1, p57Kip2, ROCK-1, gamma-catenin, and heat shock proteins, which are classified as tumor-associated genes. Three of 27 antigens-Tat-binding protein-1 (TBP-1), beta4 integrin-binding protein (p27[BBP]), and ribosomal protein L30 (rpL30)-were reacted predominantly with sera from patients with HCC (55% of patients, 45% of patients, and 20% of patients, respectively). Patients in the control group had no antibodies against these three antigens. Seventy percent of patients with HCC had the antibody against at least one of these antigens.

CONCLUSIONS

Disease specific humoral immune response against TBP-1, p27(BBP), and rpL30 was induced in patients with HCC, and the antibodies against these antigens also may be used as tumor markers.

Cancer-testis antigen expression in uterine malignancies with an emphasis on carcinosarcomas and papillary serous carcinomas

The cancer testis (CT) family of antigens are expressed in certain malignant neoplasms and are silent in normal adult tissues, except for the testis. Expression of 2 members of this family, MAGE-A4 and NY-ESO-1, has been described recently in germ cell tumors, malignant melanomas, certain carcinomas and sarcomas. Our study is the first to describe the expression pattern of CT antigens in uterine neoplasms. Ninety-eight cases of uterine neoplasms, including 41 endometrioid, 19 papillary serous and 7 clear cell carcinomas, 22 carcinosarcomas and 9 endometrial stromal sarcomas were studied. Immunohistochemistry was carried out with the 57B monoclonal antibody that recognizes predominantly the MAGE-A4 antigen in paraffinized tissues and the D8.38 antibody that recognizes NY-ESO-1. MAGE-A4 expression was found to be present in 12% of the endometrioid adenocarcinomas, 63% of the papillary serous carcinomas and 91% of the carcinosarcomas. Within the tumor population the extent of MAGE-A4 expression was highest in the carcinosarcomas. In 12 of 22 positively staining carcinosarcomas more than 50% of the tumor cells expressed MAGE-A4. NY-ESO-1 expression was seen in 19% of the endometrioid adenocarcinomas, 32% of the papillary serous carcinomas and in 45% of the carcinosarcomas. CT antigen immunoreactivity was observed in both the carcinomatous and sarcomatous components of the carcinosarcomas and strong correlation between MAGE-A4 and NY-ESO-1 expression was present in individual cases. In summary, strong MAGE-A4 expression and to a lesser degree NY-ESO-1 expression is characteristic of the vast majority of uterine carcinosarcomas and a major subset of papillary serous carcinomas. These results suggest that CT antigen expression by these tumors may represent a novel target for immunotherapy.

Immunoprofile of MITF, tyrosinase, melan-A, and MAGE-1 in HMB45-negative melanomas

A majority of desmoplastic melanomas and some of the other forms of melanomas are S-100 positive and HMB45 negative; this pattern of immunoreactivity is similar to certain nerve-derived tumors such as malignant peripheral nerve sheath tumor. In this study the immunostaining profile of HMB45-negative malignant melanomas was evaluated by a panel of antibodies against markers associated with melanoma and melanocytic differentiation, including microphthalmia transcription factor, tyrosinase, Melan-A, and MAGE-1. Immunodetection was performed on paraffin sections of 22 cases of HMB45-negative malignant melanomas (including 8 spindle cell melanomas, 8 desmoplastic melanomas, and 6 epithelioid melanomas), 8 HMB45-and S-100-positive malignant melanomas, 15 malignant peripheral nerve sheath tumors, 16 schwannomas, and 11 neurofibromas. Of eight HMB45-positive malignant melanomas, all were positive for Melan-A, tyrosinase, and melanocyte-specific transcription factor, and three were positive for MAGE-1. In the 14 HMB-45 negative, nondesmoplastic melanomas, melanocyte-specific transcription factor was positive in 9, Melan-A in 9, tyrosinase in 6, and MAGE-1 in 11. In eight desmoplastic malignant melanomas, MAGE-1 was positive in three, and all other markers were negative. The five markers tested were negative in all but two schwannomas, one with focal melanocyte-specific transcription factor and the other with tyrosinase and weak MAGE-1 reactivity. MAGE-1, melanocyte-specific transcription factor, tyrosinase, and Melan-A are useful markers in the diagnosis of malignant melanocytic lesions when HMB45 is negative. MAGE-1 may be useful in differentiating melanocytic lesions from nerve-derived lesions, but its sensitivity is relatively low. The immunostaining profile of desmoplastic malignant melanomas more closely resembles that of malignant peripheral nerve sheath tumor than that of other types of malignant melanoma. Melanocyte-specific transcription factor is not a useful marker for desmoplastic melanoma.

Monophasic and biphasic synovial sarcomas abundantly express cancer/testis antigen NY-ESO-1 but not MAGE-A1 or CT7

Synovial sarcomas are high-grade malignant mesenchymal tumors with biphasic (BSS) and monophasic (MSS) variants that carry a pathognomonic cytogenetic alteration, t(X;18), involving the SYT gene on chromosome 18 and one of several SSX genes on chromosome X, usually SSX1 or SSX2. Cancer/testis (CT) antigens are expressed in a variety of malignant neoplasms but, in normal tissues, are restricted to male germ cells. Previous analysis revealed a high incidence and homogeneous expression of MAGE CT antigen in synovial sarcomas. The present study was performed to analyze the expression of 3 CT antigens, NY-ESO-1, MAGE-A1 and CT7, by immunohistochemistry with 3 monoclonal antibodies (MAbs), ES121 (anti-NY-ESO-1), MA454 (anti-MAGE-A1) and CT7-33 (anti-CT7), in 25 synovial sarcomas (12 MSS, 13 BSS) typed for the t(X;18)-derived fusion transcript by RT-PCR (19 SYT-SSX1, 6 SYT-SSX2). NY-ESO-1 immunoreactivity was found in 20/25 (80%) cases, and antigen expression was homogeneous in 14/20 NY-ESO-1-positive cases. Both morphologic variants and both translocation types were NY-ESO-1-positive, whereas 5 SYT-SSX1 tumors (1 MSS, 4 BSS) were NY-ESO-1-negative. MAb MA454 was immunoreactive with 4/25 cases (2 MSS, 2 BSS; 3 SYT-SSX1, 1 SYT-SSX2), and MAb CT7-33 was immunoreactive with only 2/25 cases (both BSS, SYT-SSX1). Expression of MAGE-A1 and CT7 was heterogeneous in all positive cases. Our study shows that NY-ESO-1 is highly expressed in a homogeneous pattern in synovial sarcomas of both morphologic variants and both translocation types, making these tumors an attractive target for NY-ESO-1 antigen-based immunotherapy.

FUP1, a gene associated with hepatocellular carcinoma, stimulates NIH3T3 cell proliferation and tumor formation in nude mice

Human primary hepatocellular carcinoma (HCC)is one of the highly prevalent malignant diseases worldwide, the identification of HCC-associated genes has been a major approach in elucidating the molecular mechanism of tumorigenesis of HCC. In our previous studies, a function-unknown gene, which displayed marked expression difference between the HCC sample and normal liver control has been detected by cDNA microarray. This gene was named after fup1 (function-unknown protein 1), and was cloned according to the data of GenBank. The cDNA of fup1 has an open-reading frame 1233 base pairs in size. Here, the function analysis of FUP1 related to HCC is being reported. The NIH3T3 cells transiently transfected with FLAG-conjugated FUP1 revealed strong nuclear staining in immunofluorescent assay. Furthermore, cell proliferation enhancing activity of fup1 was shown by MTT assay in stable transfectant NIH3T3 cell line with pcDNA3-derived plasmid having fup1 under the regulation of pCMV, while cell proliferation repressing activity of antisense fup1 was observed in BEL7404 stable transfectant cells. Tumorigenicity of the above stable transfectant cells was analyzed in nude mice compared with appropriate controls. The result was in good agreement with MTT assay. Elevated tumorigenicity of fup1 transfected NIH3T3 cell and repressed tumorigenicity of antisense fup1 transfected BEL7404 cell were clearly demonstrated. The results above suggested that fup1 might be a critical gene related to carcinogenesis of HCC. Detailed molecular function of fup1 remains to be elucidated.

Hepatocellular carcinoma--cause, treatment and metastasis

In the recent decades, the incidence of hepatocellular carcinoma (HCC) has been found to be increasing in males in some countries. In China, HCC ranked second of cancer mortality since 1990s. Hepatitis B and C viruses (HBV and HCV) and dietary aflatoxin intake remain the major causative factors of HCC. Surgery plays a major role in the treatment of HCC, particularly for small HCC. Down-staging unresectable huge HCC to smaller HCC and followed by resection will probably be a new approach for further study. Liver transplantation is indicated for small HCC, however, some issues remain to be solved. Different modes of regional cancer therapy for HCC have been tried. Systemic chemotherapy has been disappointing in the past but the future can be promising. Biotherapy, such as cytokines, differentiation inducers, anti-angiogenic agents, gene therapy and tumor vaccine will probably play a role, particularly in the prevention of tumor recurrence. HCC invasiveness is currently the major target of study. Tremendous works have been done at the molecular level, which will provide clues for biomarker of HCC progression as well as targets for intervention.

Direct selection of a human antibody fragment directed against the tumor T-cell epitope HLA-A1-MAGE-A1 from a nonimmunized phage-Fab library

Antitumor antibodies with the same specificity as cytotoxic T lymphocytes that recognize antigenic peptides encoded by tumor-associated genes and presented by MHC class I molecules would be valuable tools to analyze the antigenicity or target tumor cells in vivo. To obtain a human antibody directed against a peptide encoded by gene melanoma-associated antigen (MAGE)-A1 and presented by HLA-A1 molecules, we selected a large phage Fab antibody repertoire on a recombinant version of the complex HLA-A1-MAGE-A1 produced by in vitro refolding. One of the selected phage antibodies shows binding to HLA-A1 complexed with the MAGE-A1 peptide, but does not show binding to HLA-A1 complexed with a peptide encoded by gene MAGE-A3 and differing from the MAGE-A1 peptide by only three residues. Phages carrying this recombinant antibody bind to HLA-A1(+) cells only after in vitro loading with MAGE-A1 peptide. These results indicate that nonimmunized phage Fab libraries are a source of antibodies with a T cell antigen receptor-like specificity. The human anti-HLA-A1-MAGE-A1 antibody described here may prove very useful for monitoring the cell surface expression of these complexes, and eventually, as a targeting reagent for the specific immunotherapy of HLA-A1 patients bearing a MAGE-A1-positive tumor.