Tumor-associated Antigen Gene Research Articles

Immunotherapy with Dendritic Cells Modified with Tumor-Associated Antigen Gene Demonstrates Enhanced Antitumor Effect Against Lung Cancer

BACKGROUND: Immunotherapy using dendritic cell (DC) vaccine has the potential to overcome the bottleneck of cancer therapy. METHODS: We engineered Lewis lung cancer cells (LLCs) and bone marrow–derived DCs to express tumor-associated antigen (TAA) ovalbumin (OVA) via lentiviral vector plasmid encoding OVA gene. We then tested the antitumor effect of modified DCs both in vitro and in vivo. RESULTS: The results demonstrated that in vitro modified DCs could dramatically enhance T-cell proliferation (P<.01) and killing of LLCs than control groups (P<.05). Moreover, modified DCs could reduce tumor size and prolong the survival of LLC tumor-bearing mice than control groups (P<.01 and P<.01, respectively). Mechanistically, modified DCs demonstrated enhanced homing to T-cell–rich compartments and triggered more naive T cells to become cytotoxic T lymphocytes, which exhibited significant infiltration into the tumors. Interestingly, modified DCs also markedly reduced tumor cells harboring stem cell markers in mice (P<.05), suggesting the potential role on cancer stem-like cells. CONCLUSION: These findings suggested that DCs bioengineered with TAA could enhance antitumor effect and therefore represent a novel anticancer strategy that is worth further exploration.

P3.02c-049 Dendritic Cells Modified with Tumor-Associated Antigen Gene Demonstrate Enhanced Antitumor Effect against Lung Cancer: Topic: IT

Immunotherapy involving dendritic cells (DCs) vaccine has the potential to overcome the bottleneck of cancer therapy. Here, we engineered Lewis Lung cancer cells (LLC) and bone marrow derived DCs to express tumor-associated antigen (TAA), ovalbumin (OVA) via lentiviral vector plasmid encoding OVA gene. We then tested the anti-tumor effect of modified DCs both in vitro and in vivo. The results demonstrated that in vitro modified DCs could dramatically enhance T cells proliferation (P < 0.01) and kill LLC significantly than control groups (P < 0.05). Moreover, modified DCs can reduce tumor size and prolong the survival of tumor-bearing mice than control groups (P < 0.01, P < 0.01; respectively). Modified DCs enhanced homing to T-cell-rich compartments and triggered naïve T cells to become cytotoxic T lymphocytes, which exhibited significant infiltration into the tumors. Interestingly, modified DCs also markedly reduced tumor cells harboring stem cell markers in mice (P < 0.05), suggesting the potential role of eliminating cancer stem-like cells in vivo. These findings indicated that DCs bioengineered with TAA may enhance antitumor effect against murine lung cancer through novel mechanism that is worth further exploration.

The cancer vaccine therapy using DCs derived from iPS cells (iPSDCs) expressing TAA gene.

768 Background: Dendritic cells (DCs) are potent antigen-presenting cells (APCs) that play a critical role in the initiation of anti-tumor immune responses. Many cancer patients have previously been treated by the cancer vaccine therapy using DCs worldwide. We have employed a study of a cancer vaccine therapy using genetically modified DCs expressing tumor-associated antigen (TAA) gene. Clinically DCs are generated from the peripheral blood monocytes of patients. Thus the number of monocytes and potential of them are limited, so they are serious obstacle. Recent studies have revealed that induced pluripotent stem (iPS) cells can be generated from murine fibroblasts. Furthermore, it has been reported that DCs can be successfully derived from murine iPS cells (iPSDCs). If the therapeutic efficacy of iPSDCs is equivalent to that of naive DCs, then the above-mentioned problems may be solved. Methods: We have induced iPSDCs from murine iPS cells by 4 steps and examined the efficacy as APCs of iPSDCs compared with naive DCs. We also examined whether a vaccine therapy using genetically modified iPSDCs can induce strong therapeutic antitumor immunity compared with naive DCs. Next, we examined the therapeutic antitumor immunity of iPSDCs expressing CEA gene compared with that of naive DCs in pre-clinical study with CEA transgenic mice. Results: We have clarified that genetically modified iPSDCs have an equal efficacy as APCs and TAA-specific therapeutic antitumor immunity, equivalent to naive DCs. And we also have clarified that genetically modified iPSDCs expressing CEA gene have a TAA-specific therapeutic antitumor immunity. Conclusions: This vaccine strategy using genetically modified iPSDCs has an equal capacity with naive DCs in terms of a therapeutic efficacy. Now, we are engaging another pre-clinical study with human, in an effort to apply in a clinical setting.

Improvement of dendritic-based vaccine efficacy against hepatitis B virus–related hepatocellular carcinoma by two tumor-associated antigen gene–infected dendritic cells

Recently, studies on dendritic cell (DC) vaccine have focused on the development of more effective DC vaccine regimen, such as the application of multiple tumor-associated antigen–targeted DC vaccine. This approach could be used to enhance efficacy of DC-based vaccine against tumors and infectious diseases. In this study, we analyzed whether DC from patients with hepatocellular carcinoma can be infected with the α-fetoprotein (AFP) gene and/or HBsAg gene (hepatocellular carcinoma–related antigen). Further, it was examined whether vaccination using these genetically engineered DC can induce stronger therapeutic antitumor immunity. Results revealed that DC infected with AdAFP (adenovirus AFP)/HBsAg can express AFP and HBsAg by reverse transcription–polymerase chain reaction and Western blot techniques. Compared with those before transfection, the expressions of membrane molecules increased dramatically. Specific T cells generated by DCs infected with AdAFP/HBsAg specifically recognized human leukocyte antigen–matched HepG2.2.15 cell lines. Moreover, the cytotoxic activity of cytotoxic T lymphocytes against HepG2.2.15 with DCs expressing AFP was significantly augmented by coinfection with the HBsAg gene. Administration with such vaccine also significantly increased the production of interleukin-12p70 and interferon-γ. Most importantly, in vivo results suggested that inhibitors of tumor growth were most significant in severe combined immunodeficiency mice model, which was treated with induced cytotoxic T lymphocyte by the AFP/HBsAg-DC vaccine. These results indicate that a vaccination therapy using DCs coinfected with the two tumor-associated antigen genes is an effective strategy for immunotherapy in the activation of DCs, CD4+ T cells, and CD8+ T cells, and may be useful in the clinical application of cancer vaccine therapy.

Co-expression patterns of tumor-associated antigen genes by non-small cell lung carcinomas: Implications for immunotherapy

Background: Polyvalent vaccination represents a recent attempt to improve the effectiveness of lung cancer immunotherapy. This study aimed to investigate whether a gene expression pattern of tumor-associated antigens (TAA) would exist indicating that their use will be most appropriate for the polyvalent vaccination of Caucasian non-small cell lung carcinoma (NSCLC) patients. We examined the concomitant expression of genes belonging to different TAA families for which expression frequencies either have never been detected in NSCLC or vary widely in the literature.Methods: Tumor material from 23 patients with NSCLC (12 adenocarcinomas, 8 squamous cell carcinomas, 3 bronchiolo - carcinomas) was examined. mRNA transcripts were detected for 5 genes of the survivin family, 5 MAGE-A genes as well as the genes of human telomerase reverse transcriptase (hTERT) and p53, by the use of quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) or semi-quantitative RT-PCR. Results: 15/23 (65%) and 8/23 (35%) tumor samples were found expressing 6-11 and 2-5 out of the 12 examined TAAs, respectively, at levels >1% of the testis reference sample. The most prevalent TAA patterns observed were those of survivin standard (survivin-std)/survivin-2B expressed by 22/23 (95.5%) tumor samples and of survivin-std/survivin-2B/hTERT expressed by 19/23 (82.5%) tumor samples. The expression levels of the survivin-std gene strongly positively correlated to those of the survivin-2B (p=0.001) and the hTERT genes (p=0.031). The number of concomitantly expressed genes was found to be positively correlated to the age of the patients (p=0.001) and the tumor size (p=0.048).Conclusion: This study provides evidence that, in Caucasian patients with NSCLC, highly prevalent expression patterns of TAA genes, predominantly of overexpressed TAAs, do exist. This result implies that the combined use of these TAA could help in designing more effective NSCLC immunotherapeutic protocols.

DENDRITIC CELL BASED VACCINES: PROGRESS IN IMMUNOTHERAPY STUDIES FOR PROSTATE CANCER

No effective treatment is currently available for metastatic prostate cancer. Dendritic cell (DC) based cancer vaccine research has emerged from the laboratories to human clinical trials. We describe progress in the development of DC based prostate cancer vaccine. The literature was reviewed for major contributions to a growing number of studies that demonstrate the potential of DC based immunotherapeutics for prostate cancer. Background topics relating to DC based immunotherapy theory and practice are also addressed. DCs have been recognized as the most efficient antigen presenting cells that have the capacity to initiate naive T cell response in vitro and in vivo. During their differentiation and maturation pathways, dendritic cells can efficiently capture, process and present antigens for T cell activation. These characteristics make DC an attractive choice as the cellular adjuvant for cancer vaccines. Advances in DC generation, loading, and maturation methodologies have made it possible to generate clinical grade vaccines for various human trials. More than 100 DC vaccine trials, including 7 studies of patients with advanced prostate cancer have been reported to date. These vaccines were generally well tolerated with no significant adverse toxicity reported. Clinical responders have been identified in these studies. The new prospects opened by DC based vaccines for prostate cancer are fascinating. When compared to conventional treatments, DC vaccinations have few side effects. Improvements in patient selection, vaccine delivery strategies, immune monitoring and vaccine manufacturing will be crucial in moving DC based prostate cancer vaccines closer to the clinics.

Genetically modified dendritic cells induced specific cytotoxity against human HCC cells in vitro

Objective: to transduce the tumor associated antigen gene MAGE-1 and/or IL-12 gene into dendritic cells (DC) and to observe the in vitro cytotoxic effect induced by the genetically modified DC against the human hepatocellular carcinoma (HCC) cell line SMMC7721. Methods: the MAGE-1 gene was inserted into the retrovirus vector LXSN to construct the recombinant retrovirus LMSN. The monocyte-derived DCs were transfected at appropriate differentiation stage by LMSN and/or a recombinant adenovirus AdmiL-12, which containing murine IL-12 gene. The control groups included retrovirus LXSN transfected, adenovirus AdBGFP transfected and non-transfected DCs. The MAGE-1 gene expression was identified by western blot and the mIL-12 p70 secretion was detected by ELISA assay. The in vitro cytotoxicities against SMMC7721 induced by genetically modified and control groups of DC were tested by MTT assay. Results: The MAGE-1 expression was detected by a monoclonal antibody in DCs tranfected with LMSN but not in control groups. At 16 h, 24 h and 48 h after transfection with AdmIL-12, the concentration of the mIL-12 p70 in the culture medium was 580pg/106 cells, 960pg/106 cells and 1100pg/106 cells respectively. The mIL-12 p70 secretions were not detected in other groups. The lytic activity (as judged by % lysis) induced by each groups of DC was 94.2±5.2% (LMSN and AdmIL-12 cotransfected group), 78.9±3.6% (LMSN transfected groups), 52.6±9.7% (AdmIL-12 transfected group), 34.7±4.3% (LXSN transfected group), 36.3±3.8% (AdBGFP transfected group) and 3.9±2.0% (non-transfected group) respectively. Except for LXSN transfected and AdBGFP transfected group, the difference of the lytic activities between other groups were statistically significant (P<0.05). Conclusion: The MAGE-1 gene modified DCs can induce relatively specific cytotoxicty against SMMC7721 in vitro and thus suggested that those genetically engineered DCs have the potential to serve as novel vaccine for HCC. Transduction of exogenous IL-12 gene into DCs may further enhance DCs’ activity and the effectiveness of the above DC vaccine.

The potential of DNA vaccination against tumor-associated antigens for antitumor therapy.

Conventional treatment approaches for malignant tumors are highly invasive and sometimes have only a palliative effect. Therefore, there is an increasing demand to develop novel, more efficient treatment options. Increased efforts have been made to apply immunomodulatory strategies in antitumor treatment. In recent years, immunizations with naked plasmid DNA encoding tumor-associated antigens have revealed a number of advantages. By DNA vaccination, antigen-specific cellular as well as humoral immune responses can be generated. The induction of specific immune responses directed against antigens expressed in tumor cells and displayed e.g., by MHC class I complexes can inhibit tumor growth and lead to tumor rejection. The improvement of vaccine efficacy has become a critical goal in the development of DNA vaccination as antitumor therapy. The use of different DNA delivery techniques and coadministration of adjuvants including cytokine genes may influence the pattern of specific immune responses induced. This brief review describes recent developments to optimize DNA vaccination against tumor-associated antigens. The prerequisite for a successful antitumor vaccination is breaking tolerance to tumor-associated antigens, which represent "self-antigens." Currently, immunization with xenogeneic DNA to induce immune responses against self-molecules is under intensive investigation. Tumor cells can develop immune escape mechanisms by generation of antigen loss variants, therefore, it may be necessary that DNA vaccines contain more than one tumor antigen. Polyimmunization with a mixture of tumor-associated antigen genes may have a synergistic effect in tumor treatment. The identification of tumor antigens that may serve as targets for DNA immunization has proceeded rapidly. Preclinical studies in animal models are promising that DNA immunization is a potent strategy for mediating antitumor effects in vivo. Thus, DNA vaccines may offer a novel treatment for tumor patients. DNA vaccines may also be useful in the prevention of tumors with genetic predisposition. By DNA vaccination preventing infections, the development of viral-induced tumors may be avoided.

Dendritic cells loaded with MART-1 peptide or infected with adenoviral construct are functionally equivalent in the induction of tumor-specific cytotoxic T lymphocyte responses in patients with melanoma.

Immunization with tumor-specific-associated antigen--pulsed dendritic cells has proved to be efficacious in various animal models and is being evaluated for the treatment of cancer in humans. Use of dendritic cells pulsed with specific peptides or transfected with tumor-associated antigen genes has been a focused area of investigation for inducing potent tumor and viral immune responses. In this study, the authors demonstrate transgene expression, including the lacZ and MART-1 genes, in dendritic cells infected with adenoviral constructs. These transiently transduced dendritic cells, derived from melanoma patients' monocytes cultured with granulocyte-macrophage colony-stimulating factor and interleukin-4, express the transgene and can stimulate patients' CD8+ T cells to elicit an antitumor immune response comparable to dendritic cells loaded with a defined peptide. These cytotoxic T lymphocytes were able to recognize both known and unknown tumor-associated antigen epitopes and exhibited cytolytic activity against HLA-matched tumor cells expressing the antigen. The ability to induce tumor-specific cytotoxic T lymphocytes in vitro using gene-modified dendritic cells that transiently express tumor-associated antigens demonstrates the potential use of these antigen-presenting cells for developing in vivo cancer vaccines.

Cytogenetic localization of cancer-related genes in the rat and comparative mapping studies in human and mouse

The rat is an important model organism in biomedical research, and several well-characterized rat cancer model systems exist. To facilitate detailed analysis of these models, it is useful to know the regional location of known cancer-related genes. In this report, 14 cancer-related genes have been sublocalized by fluorescence in situ hybridization. The mapped genes include three oncogenes (Fyn, Mas1, and Vav1), a tyrosine kinase gene (Syk), a tumor-associated antigen gene (Cd24), a growth factor receptor gene (Igf2r), the gene for an activator of c-fos/c-jun transcription factors (Apex), a transcription factor gene (Egr3), and several genes involved in steroid hormone metabolism and signaling (Esr2, Pgr, Cbg, Cyp17, and Cyp19). The remaining gene (Map1a) is involved in microtubule assembly.

Dendritic cells retrovirally transduced with a model antigen gene are therapeutically effective against established pulmonary metastases.

Dendritic cells (DCs) are bone marrow-derived leukocytes that function as potent antigen presenting cells capable of initiating T cell-dependent responses from quiescent lymphocytes. DC pulsed with tumor-associated antigen (TAA) peptide or protein have recently been demonstrated to elicit antigen-specific protective antitumor immunity in a number of murine models. Transduction of DCs with TAA genes may allow stable, prolonged antigen expression as well as the potential for presentation of multiple, or unidentified, epitopes in association with major histocompatibility complex class I and/or class II molecules. To evaluate the potential efficacy of retrovirally transduced DCs, bone marrow cells harvested from BALB/c mice were transduced with either a model antigen gene encoding beta-galactosidase (beta-gal) or a control gene encoding rat HER-2/neu (Neu) by coculture with irradiated ecotropic retroviral producer lines. Bone marrow cells were differentiated into DC in vitro using granulocyte/macrophage colony-stimulating factor and interleukin-4. After 7 d in culture, cells were 45-78% double positive for DC phenotypic cell surface markers by FACS(R) analysis, and DC transduced with beta-gal were 41-72% positive for beta-gal expression by X-gal staining. In addition, coculture of beta-gal transduced DC with a beta-gal-specific T cell line (CTLx) resulted in the production of large amounts of interferon-gamma, demonstrating that transduced DCs could process and present endogenously expressed beta-gal. DC transduced with beta-gal and control rat HER-2/neu were then used to treat 3-d lung metastases in mice bearing an experimental murine tumor CT26.CL25, expressing the model antigen, beta-gal. Treatment with beta-gal-transduced DC significantly reduced the number of pulmonary metastatic nodules compared with treatment with Hank's balanced salt solution or DCs transduced with rat HER-2/neu. In addition, immunization with beta-gal-transduced DCs resulted in the generation of antigen-specific cytotoxic T lymphocytes (CTLs), which were significantly more reactive against relevant tumor targets than CTLs generated from mice immunized with DCs pulsed with the Ld-restricted beta-gal peptide. The results observed in this rapidly lethal tumor model suggest that DCs transduced with TAA may be a useful treatment modality in tumor immunotherapy.

Human melanoma antigen MAGE-1 peptide; tumor-associated antigen gene cloning and expression for use in antitumor recombinant vaccine production : Cytel World 9504 542; 16 February 1995

Human melanoma antigen MAGE-1 peptide; tumor-associated antigen gene cloning and expression for use in antitumor recombinant vaccine production : Cytel World 9504 542; 16 February 1995

Sequence investigation of the major gastrointestinal tumor-associated antigen gene family, GA733.

The monoclonal antibody-defined, tumor-associated antigen GA733 was purified from the SW948 human colorectal carcinoma cell line and its partial amino acid sequence was determined. By using a synthetic oligonucleotide probe, two recombinants were isolated from a total human genomic library. We prove the existence of a family of GA733 genes. One of the genomic isolates is demonstrated to be an intronless gene, which is transcribed in pancreatic carcinoma cell lines and in placenta. The GA733 proteins were observed to contain sequences homologous to a repeat unit occurring 10 times in thyroglobulin and once in the HLA-DR-associated invariant chain. A more evolutionarily distant relationship was found with the alpha chain of the interleukin 2 growth factor receptor.