LAGE-1, a new gene with tumor specificity

Investigating the inhibitory and penetrating properties of three novel anticancer and antimicrobial scorpion peptides via molecular docking and molecular dynamic simulation

The two types of bladder cancer, muscle invasive and non-muscle invasive (NMIBC), are among the most prevalent cancers worldwide. Despite this, even though muscle-invasive bladder cancer is more deadly, NMIBC requires more therapy due to a greater recurrence rate and more extended and expensive care. Immunotherapy, intravesical chemotherapy, cystoscopy, and transurethral resection (TUR) are among the treatments available. Crude scorpion venomand purified proteins and peptides, can suppress cancer metastasis in an in vitro or in vivo context, suppress cancer growth, halt the cell cycle, and cause cell apoptosis, according to an increasing number of experimental and preclinical studies. In this research, three novels discovered peptides (P2, P3 and P4. ProteomeXchange: PXD036231) from Buthotus saulcyi and, Odontobuthus doriae scorpions were used along with a peptide called pantinin (as a control). The phylogenetic tree showed that the peptides belong to Chaperonin HSP60, Chrysophsin2 and Pheromone-binding protein2, respectively. These peptides were docked with four known antigens, BAGE, BLCAP, PRAME and ROR1 related to bladder cancer and three bacterial antigens FliC, FliD and FimH to investigate their antimicrobial and anticancer properties. The results showed that peptides 2 and 3 have the best binding rate. The MD simulation results also confirmed the binding of peptides 2 and 3 to antigens. The penetration power of peptides 2 and 3 in the membrane of cancer cells and bacterial cells was also simulated, and the results of RMSD and PD confirmed it. QSAR suggests that peptides 2 and 3 can act as anti-cancer and anti-microbial peptides.Communicated by Ramaswamy H. Sarma.

A synthetic DNA template for fast manufacturing of versatile single epitope mRNA

A flexible, affordable, and rapid vaccine platform is necessary to unlock the potential of personalized cancer vaccines in order to achieve full clinical efficiency. mRNA cancer vaccine manufacture relies on the rigid sequence design of multiepitope constructs produced by laborious bacterial cloning and time-consuming plasmid preparation. Here, we introduce a synthetic DNA template (SDT) assembly process, which allows cost- and time-efficient manufacturing of single (neo)epitope mRNA. We benchmarked SDT-derived mRNA against mRNA derived from a plasmid DNA template (PDT), showing that monocyte-derived dendritic cells (moDCs) electroporated with SDT-mRNA or PDT-mRNA, encoding HLA-I- or HLA-II-restricted (neo)epitopes, equally activated T cells that were modified to express the cognate T cell receptors. Furthermore, we validated the SDT-mRNA platform for neoepitope immunogenicity screening using the characterized HLA-A2-restricted neoepitope DHX40B and four new candidate HLA-A2-restricted melanoma neoepitopes. Finally, we compared SDT-mRNA with PDT-mRNA for vaccine development purposes. moDCs electroporated with mRNA encoding the HLA-A2-restricted, mutated Melan-A/Mart-1 epitope together with TriMix mRNA-generated high levels of functional Melan-A/Mart-1-specific CD8⁺ T cells. In conclusion, SDT single epitope mRNA can be manufactured in a more flexible, cost-efficient, and time-efficient way compared with PDT-mRNA, allowing prompt neoepitope immunogenicity screening, and might be exploited for the development of personalized cancer vaccines.

A Novel Multiepitope Vaccine Against Bladder Cancer Based on CTL and HTL Epitopes for Induction of Strong Immune Using Immunoinformatics Approaches

Bladder cancer is well-known cancer in two forms of muscle-invasive and non-muscle-invasive bladder cancer which is responsible for annual deaths worldwide. Common therapies methods are somewhat successful; however, these methods have the limitations such as the side effects of chemotherapy which necessitate the requirement for new preventive methods against bladder cancer. Hence, we explain a novel designed multi-epitope vaccine against bladder cancer using the immunoinformatics tool. Three well-known BLCAP, PRAM, and BAGE4 antigens were evaluated due to most repetitive CTL and HTL epitopes binding. IFNγ and IL10 inducer potential of selected epitopes were investigated, as well as liner and conformational B-cell epitopes. Human beta-defensin 3 and PADRE sequence were added to construct as adjuvants, along with EAAAK, AAY, and GGGS linkers to fuse CTL and HTL epitopes. Results showed this construct encodes a soluble, non-toxic, and non-allergic protein with 70 kDa molecular weight. Modeled 3D structure of vaccine was docked whit Toll-Like Receptors (TLR) of 7/8. Docking, molecular dynamics simulation and MMBPSA analysis confirmed stability of vaccine-TLR complexes. The immunogenicity showed this construct could elicit humoral and cellular immune responses. In silico and immunoinformatics evaluations suggest that this construct is a recombinant candidate vaccine against bladder cancer.

Role and Clinical Utility of Cancer/Testis Antigens in Head and Neck Squamous Cell Carcinoma

Cancer/testis (CT) antigens exhibit selective expression predominantly in immunoprivileged tissues in non-pathological contexts but are aberrantly expressed in diverse cancers. Due to their expression pattern, they have historically been attractive targets for immunotherapies. A growing number of studies implicate CT antigens in almost all hallmarks of cancer, suggesting that they may act as cancer drivers. CT antigens are expressed in head and neck squamous cell carcinomas. However, their role in the pathogenesis of these cancers remains poorly studied. Given that CT antigens hold intriguing potential as therapeutic targets and as biomarkers for prognosis and that they can provide novel insights into oncogenic mechanisms, their further study in the context of head and squamous cell carcinoma is warranted.

Analysis of LAGEs Family Gene Signature and Prognostic Relevance in Breast Cancer

Breast cancer (BRCA) is one of the most complex diseases and involves several biological processes. Members of the L-antigen (LAGE) family participate in the development of various cancers, but their expressions and prognostic values in breast cancer remain to be clarified. High-throughput methods for exploring disease progression mechanisms might play a pivotal role in the improvement of novel therapeutics. Therefore, gene expression profiles and clinical data of LAGE family members were acquired from the cBioportal database, followed by verification using the Oncomine and The Cancer Genome Atlas (TCGA) databases. In addition, the Kaplan-Meier method was applied to explore correlations between expressions of LAGE family members and prognoses of breast cancer patients. MetaCore, GlueGo, and GluePedia were used to comprehensively study the transcript expression signatures of LAGEs and their co-expressed genes together with LAGE-related signal transduction pathways in BRCA. The result indicated that higher LAGE3 messenger (m)RNA expressions were observed in BRCA tissues than in normal tissues, and they were also associated with the stage of BRCA patients. Kaplan-Meier plots showed that overexpression of LAGE1, LAGE2A, LAGE2B, and LAGE3 were highly correlated to poor survival in most types of breast cancer. Significant associations of LAGE family genes were correlated with the cell cycle, focal adhesion, and extracellular matrix (ECM) receptor interactions as indicated by functional enrichment analyses. Collectively, LAGE family members’ gene expression levels were related to adverse clinicopathological factors and prognoses of BRCA patients; therefore, LAGEs have the potential to serve as prognosticators of BRCA patients.

Specific Inhibition of Tumor Growth by T Cell Receptor-Drug Conjugates Targeting Intracellular Cancer-Testis Antigen NY-ESO-1/LAGE-1

Despite the significant therapeutic advances in T-cell immunotherapy, many malignancies remain unresponsive, which might be because of the negative regulation of T cells by the tumor microenvironment (TME). T cells discriminate tumor cells and normal cells through T-cell receptors (TCRs); therefore, we generated a novel type of TCR-drug conjugates (TDCs) by referring antibody-drug conjugations (ADCs) to overcome the effects of the TME on T cells while preserving the specificity of TCR for tumor recognition. We selected HLA-A2/NY-ESO-1_157-165 (peptide NY-ESO-1_157-165 in complex with human leukocyte antigen serotype HLA-A*02:01) as the antigen and the antigen-specific TCR (1G4113) as the carrier. By sortase A-mediated ligation, we obtained three NY-TCR-vcMMAEs and further studied their properties, antitumor activity, and toxicity in vitro and in vivo. We found that all the NY-TCR-vcMMAEs had high endocytosis efficiency and specifically killed HLA-A2/NY-ESO-1_157-165 positive tumor cells. In xenograft models, one of the TDCs, NY-TCR-2M, was effectively and specifically distributed into tumor tissues and inhibited tumor growth without inducing obvious toxicity. Our results demonstrated that TCRs can be carriers of toxic payloads and that the TDCs thus formed can specifically inhibit tumor growth, neglecting the immune microenvironment.

NY-ESO-1 Protein Vaccine Combining Alum, CpG ODN, and HH2 Complex Adjuvant Induces Protective and Therapeutic Anti-Tumor Responses in Murine Multiple Myeloma

Background

NY-ESO-1 is an ideal target for multiple myeloma immunotherapy. Alum, CpG ODN and HH2 complex is a safe and effective adjuvant for cancer vaccine.

Methods

We constructed NY-ESO-1 protein vaccine combined with alum, CpG ODN, and HH2 complex adjuvant to immunize the BALB/c mice inoculated with NS-1 murine multiple myeloma cells. Then, we determined the immunogenicity and anti-tumor effects in prophylactic and therapeutic models by analyzing the NY-ESO-1 antibody titer, evaluating IL4/INF-γ expression, and assessing cytotoxic T lymphocytes activities. The side-effects of vaccines were also evaluated.

Results

The group of NY-ESO-1 protein vaccine combining alum, CpG ODN, and HH2 complex adjuvant is more capable of stimulating both humoral and cellular tumor-specific immune responses to prolong the survival of the mice and inhibit tumor growth in prophylactic and therapeutic immunotherapy. The marked side-effects were not detected in immunized mice.

Discussion

The results suggest that alum, CpG ODN, and HH2 complex as a novel immune adjuvant combined cancer vaccine could improve the immunity efficiency in a murine multiple myeloma model.

Long-term safety and activity of NY-ESO-1 SPEAR T cells after autologous stem cell transplant for myeloma

This study in patients with relapsed, refractory, or high-risk multiple myeloma (MM) evaluated the safety and activity of autologous T cells engineered to express an affinity-enhanced T-cell receptor (TCR) that recognizes a peptide shared by cancer antigens New York esophageal squamous cell carcinoma-1 (NY-ESO-1) and L-antigen family member 1 (LAGE-1) and presented by HLA-A*02:01. T cells collected from 25 HLA-A*02:01-positive patients with MM expressing NY-ESO-1 and/or LAGE-1 were activated, transduced with self-inactivating lentiviral vector encoding the NY-ESO-1^c259TCR, and expanded in culture. After myeloablation and autologous stem cell transplant (ASCT), all 25 patients received an infusion of up to 1 × 10¹⁰ NY-ESO-1 specific peptide enhanced affinity receptor (SPEAR) T cells. Objective response rate (International Myeloma Working Group consensus criteria) was 80% at day 42 (95% confidence interval [CI], 0.59-0.93), 76% at day 100 (95% CI, 0.55-0.91), and 44% at 1 year (95% CI, 0.24-0.65). At year 1, 13/25 patients were disease progression-free (52%); 11 were responders (1 stringent complete response, 1 complete response, 8 very good partial response, 1 partial response). Three patients remained disease progression-free at 38.6, 59.2, and 60.6 months post-NY-ESO-1 SPEAR T-cell infusion. Median progression-free survival was 13.5 months (range, 3.2-60.6 months); median overall survival was 35.1 months (range, 6.4-66.7 months). Infusions were well tolerated; cytokine release syndrome was not reported. No fatal serious adverse events occurred during study conduct. NY-ESO-1 SPEAR T cells expanded in vivo, trafficked to bone marrow, demonstrated persistence, and exhibited tumor antigen-directed functionality. In this MM patient population, NY-ESO-1 SPEAR T-cell therapy in the context of ASCT was associated with antitumor activity. This trial was registered at www.clinicaltrials.gov as #NCT01352286.

MAGE-A4, NY-ESO-1 and SAGE mRNA expression rates and co-expression relationships in solid tumours

Background

Cancer testis (CT) antigens are promising targets for cancer immunotherapies such as cancer vaccines and genetically modified adoptive T cell therapy. In this study, we evaluated the expression of three CT antigens, melanoma-associated antigen A4 (MAGE-A4), New York oesophageal squamous cell carcinoma 1 (NY-ESO-1) and sarcoma antigen gene (SAGE).

Methods

MAGE-A4, NY-ESO-1 and/or SAGE antigen expression in tumour samples was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Informed consent was obtained from individuals prior to study enrolment.

Results

In total, 585 samples in 21 tumour types were evaluated between June 2009 and March 2018. The positive expression rates of these CT antigens were as follows: MAGE-A4, 34.6% (range, 30.7–38.7); NY-ESO-1, 21.0% (range, 17.2–25.1); and SAGE, 21.8% (range, 18.5–25.4). The MAGE-A4 antigen was expressed in 54.9% of oesophageal cancers, 37.5% of head and neck cancers, 35.0% of gastric cancers and 34.2% of ovarian cancers; the NY-ESO-1 antigen was expressed in 28.6% of lung cancers, 25.3% of oesophageal cancers and 22.6% of ovarian cancers; and the SAGE antigen was expressed in 35.3% of prostate cancers, 32.9% of oesophageal cancers and 26.3% of ovarian cancers. The most common tumour type in this study was oesophageal cancer. MAGE-A4, NY-ESO-1 and SAGE antigen expression were assessed in 214 oesophageal cancer samples, among which 24 (11.2%) were triple-positive, 58 (27.1%) were positive for any two, 59 (27.6%) were positive for any one, and 73 (34.1%) were triple negative.

Conclusions

Oesophageal cancer exhibited a relatively high rate of CT antigen mRNA expression positivity.

Immunotherapy for Gynecologic Cancer: Current Applications and Future Directions

The role of the immune system in the development of cancer has been a subject of ongoing clinical investigation in recent years. Emerging data demonstrate that tumorigenesis resulting in ovarian, uterine, and cervical cancers is a consequence of impaired host immune responses to cancerous cells. Leveraging the immune system through the use of immune checkpoint inhibitors, therapeutic vaccine therapy, and adoptive cell transfer presents a profound opportunity to revolutionize cancer treatment. This review will encompass the role of the immune system in development of gynecologic cancers and highlight recent data regarding immunotherapy applications in ovarian, uterine, and cervical cancers.

Prioritization and comprehensive analysis of genes associated with melanoma

Melanoma is a malignant tumor derived from melanocytes, which occurs mostly in the skin. A major challenge in cancer research is the biological interpretation of the complexity of cancer somatic mutation profiles. The aim of the present study was to obtain a comprehensive understanding of the formation and development of melanoma and to identify its associated genes. In the present study, a pipeline was proposed for investigating key genes associated with melanoma based on the Online Mendelian Inheritance in Man and Search Tool for the Retrieval of Interacting Genes/Proteins databases through a random walk model. Additionally, functional enrichment analysis was performed for key genes associated with melanoma. This identified a total of 17 biological processes and 30 pathways which may be associated with melanoma. In addition, melanoma-specific network analysis followed by Kaplan-Meier analysis along with log-rank tests identified tyrosinase, hedgehog acyltransferase, BRCA1-associated protein 1 and melanocyte inducing transcription factor as potential therapeutic targets for melanoma. In conclusion, the present study increased the knowledge of melanoma progression and may be helpful for improving its prognosis.

Expression of cancer-testis antigens in esophageal cancer and their progress in immunotherapy

Purpose

Esophageal cancer is a common disease in China with low survival rate due to no obvious early symptoms and lack of effective screening strategies. Traditional treatments usually do not produce desirable results in patients with advanced esophageal cancer, so immunotherapy which relies on tumor-related antigens is needed to combat low survival rates effectively. Cancer–testis antigens (CTA), a large family of tumor-related antigens, have a strong in vivo immunogenicity and tumor-restricted expressing patterns in normal adult tissues. These two characteristics are ideal features of anticancer immunotherapy targets and, therefore, promoted the development of some studies of CTA-based therapy. To provide ideas for the role of the cancer–testis antigens MAGE-A, NY-ESO-1, LAGE-1, and TTK in esophageal cancer, we summarized their expression, prognostic value, and development in immunotherapy.

Methods

The relevant literature from PubMed is reviewed in this study.

Results

In esophageal cancer, although the relationship between expression of MAGE-A, NY-ESO-1, LAGE-1, and TTK and prognosis value is still in a controversial situation, MAGE-A, NY-ESO-1, LAGE-1, and TTK are highly expressed and can induce specific CTL cells to produce particular killing effect on tumor cells, and some clinical trials have demonstrated that immunotherapy for esophageal cancer patients is effective and safe, which provides a new therapeutic strategy for the treatment of esophageal cancer in the future.

Conclusion

In this review, we summarize expression and prognostic value of MAGE-A, NY-ESO-1, LAGE-1, and TTK in esophageal cancer and point out recent advances in immunotherapy about them.

Emerging Role and Future Directions of Immunotherapy in Advanced Ovarian Cancer

Clinical progress in cancer immunotherapy has been slow; however, within the last 5 years, breakthrough successes have brought immunotherapy to the forefront in cancer therapy. Promising results have been observed in solid tumors and hematologic malignancies. Most treatment modalities have shown limited efficacy as monotherapy. The complex nature of cancer and the immunosuppressive microenvironment emphasizes the need to personalize immunotherapy by manipulating the patient's own immune system. For successful and long-lasting cure of cancer, a multimodal approach is essential, combining antitumor cell therapy with manipulation of multiple pathways in the tumor microenvironment to ameliorate tumor-induced immunosuppression.

Cancer-testis antigens: Unique cancer stem cell biomarkers and targets for cancer therapy

Cancer-testis antigens (CTAs) are considered as unique and promising cancer biomarkers and targets for cancer therapy. CTAs are multifunctional protein group with specific expression patterns in normal embryonic and adult cells and various types of cancer cells. CTAs are involved in regulating of the basic cellular processes during development, stem cell differentiation and carcinogenesis though the biological roles and cell functions of CTA families remain largely unclear. Analysis of CTA expression patterns in embryonic germ and somatic cells, pluripotent and multipotent stem cells, cancer stem cells and their cell descendants indicates that rearrangements of characteristic CTA profiles (aberrant expression) could be associated with cancer transformation and failure of the developmental program of cell lineage specification and germ line restriction. Therefore, aberrant CTA profiles can be used as panels of biomarkers for diagnoses and the selection of cancer treatment strategies. Moreover, immunogenic CTAs are prospective targets for cancer immunotherapy. Clinical trials testing broad range of cancer therapeutic vaccines against antigens of MAGEA and NY-ESO-1 families for treating various cancers have shown mixed clinical efficiency, safety and tolerability, suggesting the requirement of in-depth research of CTA expression in normal and cancer stem cells and extensive clinical trials for improving cancer immunotherapy technologies. This review focuses on recent advancement in study of CTAs in normal and cancer cells, particularly in normal and cancer stem cells, and provides a new insight into CTA expression patterns during normal and cancer stem cell lineage development. Additionally, new approaches in development of effective CTA-based therapies exclusively targeting cancer stem cells will be discussed.

BAP31, a newly defined cancer/testis antigen, regulates proliferation, migration, and invasion to promote cervical cancer progression

Malignant tumors typically undergo an atavistic regression characterized by the overexpression of embryonic genes and proto-oncogenes, including a variety of cancer/testis antigens (CTAs) that are testis-derived and are not expressed or expressed in trace amounts in somatic tissues. Based on this theory, we established a new method to identify unknown CTAs, the spermatogenic cells-specific monoclonal antibody-defined cancer/testis antigen (SADA) method. Using the SADA method, we identified BAP31 as a novel CTA and confirmed that BAP31 expression is associated with progression and metastasis of several cancers, particularly in cervical cancer. We found that BAP31 was significantly upregulated in stage I, II, and III cervical cancer patients and highly correlated with poor clinic outcomes. We further demonstrated that BAP31 regulates cervical cancer cell proliferation by arresting the cell cycle at the G0/G1 stage and that depletion of BAP31 inhibits hyper-proliferation. Moreover, depletion of BAP31 inhibits cervical cancer cell invasion and migration by regulating the expression and subcellular localization of Drebrin, M-RIP, SPECC1L, and Nexilin, and then affect the cytoskeleton assemblage. Finally, the depletion of BAP31 prevents cervical cancer progression and metastasis in vivo. These findings provide a new method for identifying novel CTAs as well as mechanistic insights into how BAP31 regulates cervical cancer hyper-proliferation and metastasis.

NY-ESO-1 Based Immunotherapy of Cancer: Current Perspectives

NY-ESO-1 or New York esophageal squamous cell carcinoma 1 is a well-known cancer-testis antigen (CTAs) with re-expression in numerous cancer types. Its ability to elicit spontaneous humoral and cellular immune responses, together with its restricted expression pattern, have rendered it a good candidate target for cancer immunotherapy. In this review, we provide background information on NY-ESO-1 expression and function in normal and cancerous tissues. Furthermore, NY-ESO-1-specific immune responses have been observed in various cancer types; however, their utility as biomarkers are not well determined. Finally, we describe the immune-based therapeutic options targeting NY-ESO-1 that are currently in clinical trial. We will highlight the recent advancements made in NY-ESO-1 cancer vaccines, adoptive T cell therapy, and combinatorial treatment with checkpoint inhibitors and will discuss the current trends for future NY-ESO-1 based immunotherapy. Cancer treatment has been revolutionized over the last few decades with immunotherapy emerging at the forefront. Immune-based interventions have shown promising results, providing a new treatment avenue for durable clinical responses in various cancer types. The majority of successful immunotherapy studies have been reported in liquid cancers, whereas these approaches have met many challenges in solid cancers. Effective immunotherapy in solid cancers is hampered by the complex, dynamic tumor microenvironment that modulates the extent and phenotype of the antitumor immune response. Furthermore, many solid tumor-associated antigens are not private but can be found in normal somatic tissues, resulting in minor to detrimental off-target toxicities. Therefore, there is an ongoing effort to identify tumor-specific antigens to target using various immune-based modalities. CTAs are considered good candidate targets for immunotherapy as they are characterized by a restricted expression in normal somatic tissues concomitant with a re-expression in solid epithelial cancers. Moreover, several CTAs have been found to induce a spontaneous immune response, NY-ESO-1 being the most immunogenic among the family members. Hence, this review will focus on NY-ESO-1 and discuss the past and current NY-ESO-1 targeted immunotherapeutic strategies.

The cancer-testis antigens SPANX-A/C/D and CTAG2 promote breast cancer invasion

Genes that are normally biased towards expression in the testis are often induced in tumor cells. These gametogenic genes, known as cancer-testis antigens (CTAs), have been extenstively investigated as targets for immunotherapy. However, despite their frequent detection, the degree to which CTAs support neoplastic invasion is poorly understood. Here, we find that the CTA genes SPANX-A/C/D and CTAG2 are coordinately induced in breast cancer cells and regulate distinct features of invasive behavior. Our functional analysis revealed that CTAG2 interacts with Pericentrin at the centrosome and is necessary for directional migration. Conversely, SPANX-A/C/D interacts with Lamin A/C at the inner nuclear membrane and is required for the formation of actin-rich cellular protrusions that reorganize the extracellular matrix. Importantly, SPANX-A/C/D was required for breast cancer cells to spontaneously metastasize to the lung, demonstrating that CTA reactivation can be critical for invasion dependent phenotypes in vivo. Moreover, elevated SPANX-A/C/D expression in breast cancer patient tumors correlated with poor outcome. Together, our results suggest that distinct CTAs promote tumor progression by regulating complementary cellular functions that are integrated together to induce invasive behavior.

Immune targets and neoantigens for cancer immunotherapy and precision medicine

Harnessing the immune system to eradicate malignant cells is becoming a most powerful new approach to cancer therapy. FDA approval of the immunotherapy-based drugs, sipuleucel-T (Provenge), ipilimumab (Yervoy, anti-CTLA-4), and more recently, the programmed cell death (PD)-1 antibody (pembrolizumab, Keytruda), for the treatment of multiple types of cancer has greatly advanced research and clinical studies in the field of cancer immunotherapy. Furthermore, recent clinical trials, using NY-ESO-1-specific T cell receptor (TCR) or CD19-chimeric antigen receptor (CAR), have shown promising clinical results for patients with metastatic cancer. Current success of cancer immunotherapy is built upon the work of cancer antigens and co-inhibitory signaling molecules identified 20 years ago. Among the large numbers of target antigens, CD19 is the best target for CAR T cell therapy for blood cancer, but CAR-engineered T cell immunotherapy does not yet work in solid cancer. NY-ESO-1 is one of the best targets for TCR-based immunotherapy in solid cancer. Despite the great success of checkpoint blockade therapy, more than 50% of cancer patients fail to respond to blockade therapy. The advent of new technologies such as next-generation sequencing has enhanced our ability to search for new immune targets in onco-immunology and accelerated the development of immunotherapy with potentially broader coverage of cancer patients. In this review, we will discuss the recent progresses of cancer immunotherapy and novel strategies in the identification of new immune targets and mutation-derived antigens (neoantigens) for cancer immunotherapy and immunoprecision medicine.

New York esophageal squamous cell carcinoma-1 and cancer immunotherapy

New York esophageal squamous cell carcinoma 1 (NY-ESO-1) is a known cancer testis gene with exceptional immunogenicity and prevalent expression in many cancer types. These characteristics have made it an appropriate vaccine candidate with the potential application against various malignancies. This article reviews recent knowledge about the NY-ESO-1 biology, function, immunogenicity and expression in cancers as well as and the results of clinical trials with this antigen.

Immunotherapy in Multiple Myeloma Using Cancer-Testis Antigens

Context:

Multiple myeloma (MM) is a B-cell malignancy characterized by monoclonal expansion of abnormal plasma cells in the bone marrow. It accounts for 10% of hematological malignancies. Although patients respond to a wide range of anticancer modalities, relapse occurs in a significant number of the cases. Immunotherapeutic approaches have been evolved to tackle this problem. Cancer-testis antigens CTAs as a group of tumor-associated antigens are appropriate targets for cancer immunotherapy as they have restricted expression pattern in normal tissues except for testis which is an immune-privileged site. Expression of these antigens has been assessed in different malignancies including MM.

Evidence Acquisition:

We performed a computerized search of the MEDLINE/PubMed databases with key words: multiple myeloma, cancer-testis antigen, and cancer stem cell and immunotherapy.

Results:

Several CTAs including NY-ESO-1, MAGE and GAGE family have been shown to be expressed in MM patients. Cellular and humoral immune responses against these antigens have been detected in MM patients.

Conclusions:

The frequent and high expression level of CTAs in MM patients shows that these antigens can be applied as cancer biomarkers as well as targets for immunotherapy in these patients.

Human Tumor Antigens and Cancer Immunotherapy

With the recent developments of adoptive T cell therapies and the use of new monoclonal antibodies against the immune checkpoints, immunotherapy is at a turning point. Key players for the success of these therapies are the cytolytic T lymphocytes, which are a subset of T cells able to recognize and kill tumor cells. Here, I review the nature of the antigenic peptides recognized by these T cells and the processes involved in their presentation. I discuss the importance of understanding how each antigenic peptide is processed in the context of immunotherapy and vaccine delivery.

Expression of cancer-testis antigens MAGEA1, MAGEA3, ACRBP, PRAME, SSX2, and CTAG2 in myxoid and round cell liposarcoma

Myxoid and round-cell liposarcoma is a frequently encountered liposarcoma subtype. The mainstay of treatment remains surgical excision with or without chemoradiation. However, treatment options are limited in the setting of metastatic disease. Cancer-testis antigens are immunogenic antigens with the expression largely restricted to testicular germ cells and various malignancies, making them attractive targets for cancer immunotherapy. Gene expression studies have reported the expression of various cancer-testis antigens in liposarcoma, with mRNA expression of CTAG1B, CTAG2, MAGEA9, and PRAME described specifically in myxoid and round-cell liposarcoma. Herein, we further explore the expression of the cancer-testis antigens MAGEA1, ACRBP, PRAME, and SSX2 in myxoid and round-cell liposarcoma by immunohistochemistry in addition to determining mRNA levels of CTAG2 (LAGE-1), PRAME, and MAGEA3 by quantitative real-time PCR. Samples in formalin-fixed paraffin-embedded blocks (n=37) and frozen tissue (n=8) were obtained for immunohistochemistry and quantitative real-time PCR, respectively. Full sections were stained with antibodies to MAGEA1, ACRBP, PRAME, and SSX2 and staining was assessed for intensity (1-2+) and percent tumor positivity. The gene expression levels of CTAG2, PRAME, and MAGEA3 were measured by quantitative real-time PCR. In total, 37/37 (100%) of the samples showed predominantly strong, homogenous immunoreactivity for PRAME. There was a variable, focal expression of MAGEA1 (11%) and SSX2 (16%) and no expression of ACRBP. Quantitative real-time PCR demonstrated PRAME and CTAG2 transcripts in all eight samples: six tumors with high mRNA levels; two tumors with low mRNA levels. The gene expression of MAGEA3 was not detected in the majority of cases. In conclusion, myxoid and round-cell liposarcomas consistently express PRAME by immunohistochemistry as well as CTAG2 and PRAME by qualitative real-time PCR. This supports the use of cancer-testis antigen-targeted immunotherapy in the treatment of this malignancy.

Reexpression of LSAMP inhibits tumor growth in a preclinical osteosarcoma model

BACKGROUND

Osteosarcomas are the most common primary malignant tumors of bone, showing complex chromosomal rearrangements with multiple gains and losses. A frequent deletion within the chromosomal region 3q13.31 has been identified by us and others, and is mainly reported to be present in osteosarcomas. The purpose of the study was to further characterize the frequency and the extent of the deletion in an extended panel of osteosarcoma samples, and the expression level of the affected genes within the region. We have identified LSAMP as the target gene for the deletion, and have studied the functional implications of LSAMP-reexpression.

METHODS

LSAMP copy number, expression level and protein level were investigated by quantitative PCR and western blotting in an osteosarcoma panel. The expression of LSAMP was restored in an osteosarcoma cell line, and differences in proliferation rate, tumor formation, gene expression, migration rate, differentiation capabilities, cell cycle distribution and apoptosis were investigated by metabolic dyes, tumor formation in vivo, gene expression profiling, time-lapse photography, differentiation techniques and flow cytometry, respectively.

RESULTS

We found reduced copy number of LSAMP in 45/76 osteosarcoma samples, reduced expression level in 25/42 samples and protein expression in 9/42 samples. By restoring the expression of LSAMP in a cell line with a homozygous deletion of the gene, the proliferation rate in vitro was significantly reduced and tumor growth in vivo was significantly delayed. In response to reexpression of LSAMP, mRNA expression profiling revealed consistent upregulation of the genes hairy and enhancer of split 1 (HES1), cancer/testis antigen 2 (CTAG2) and kruppel-like factor 10 (KLF10).

CONCLUSIONS

The high frequency and the specificity of the deletion indicate that it is important for the development of osteosarcomas. The deletion targets the tumor suppressor LSAMP, and based on the functional evidence, the tumor suppressor function of LSAMP is most likely exerted by reducing the proliferation rate of the tumor cells, possibly by indirectly upregulating one or more of the genes HES1, CTAG2 or KLF10. To our knowledge, this study describes novel functions of LSAMP, a first step to understanding the functional role of this specific deletion in osteosarcomas.

Tumour antigens recognized by T lymphocytes: at the core of cancer immunotherapy

In this Timeline, we describe the characteristics of tumour antigens that are recognized by spontaneous T cell responses in cancer patients and the paths that led to their identification. We explain on what genetic basis most, but not all, of these antigens are tumour specific: that is, present on tumour cells but not on normal cells. We also discuss how strategies that target these tumour-specific antigens can lead either to tumour-specific or to crossreactive T cell responses, which is an issue that has important safety implications in immunotherapy. These safety issues are even more of a concern for strategies targeting antigens that are not known to induce spontaneous T cell responses in patients.

HLA-DRB1*0410-Restricted Recognition of XAGE-1b37-48 Peptide by CD4 T Cells

XAGE-1b belongs to cancer/testis (CT) antigens, and has been shown to be expressed frequently in lung cancers and to elicit an antibody response in patients with XAGE-1b-expressing tumors. In this study, we investigated an XAGE-1b peptide recognized by CD4 T cells. CD4 T cells were purified from PBMC of a healthy donor and stimulated with pooled 25-mer peptides overlapped with 15 amino acids spanning the entire XAGE-1b protein. The generation of XAGE-1b-specific CD4 T cells was shown by IFNgamma secretion assay. A CD4 T cell clone OHD1 was obtained by limiting dilution. OHD1 recognized two overlapping peptides, XAGE1-b(33-49) and XAGE-1b(37-52), by ELISPOT assay. A peptide XAGE-1b(38-46) which was included in both XAGE-1b(33-49) and XAGE-1b(37-52) was predicted to be a DRB1*0410-restricted 9-mer peptide by a computer-based program. We identified the 12-mer peptide XAGE-1b(37-48) as a new XAGE-1b epitope restricted to HLA-DRB1*0410.

DNA fusion vaccine designs to induce tumor-lytic CD8+ T-cell attack via the immunodominant cysteine-containing epitope of NY-ESO 1

The cancer/testis antigen NY-ESO-1 contains an immunodominant HLA-A2-binding peptide (SLLMWITQC), designated S9C, an attractive target for vaccination against several human cancers. As cysteine contains a reactive -SH, the oxidation status of exogenous synthetic peptide is uncertain. We have designed tolerance-breaking DNA fusion vaccines incorporating a domain of tetanus toxin fused to tumor-derived peptide sequences (p.DOM-peptide), placed at the C-terminus for optimal immunogenicity. In a "humanized" HLA-A2 preclinical model, p.DOM-S9C primed S9C-specific CD8+ T cells more effectively than adjuvanted synthetic peptide. A DNA vaccine encoding the full NY-ESO-1 sequence alone induced only weak S9C-specific responses, amplified by addition of DOM sequence. The analog peptide (SLLMWITQL) also primed peptide-specific CD8+ T cells, again increased by DNA delivery. Importantly, T cells induced by S9C-encoding DNA vaccines killed tumor cells expressing endogenous NY-ESO-1. Only a fraction of T cells induced by the S9L-encoding DNA vaccines was able to recognize S9C and kill tumor cells. These data indicate that DNA vaccines mimic posttranslational modifications of -SH-containing peptides expressed by tumor cells. Instability of synthetic peptides and the potential dangers of analog peptides contrast with the ability of DNA vaccines to induce high levels of tumor-lytic peptide-specific CD8+ T cells. These findings encourage clinical exploration of this vaccine strategy to target NY-ESO-1.

Inhibition of the receptor tyrosine kinase ROR1 by anti-ROR1 monoclonal antibodies and siRNA induced apoptosis of melanoma cells

The receptor tyrosine kinase (RTK) ROR1 is overexpressed and of importance for the survival of various malignancies, including lung adenocarcinoma, breast cancer and chronic lymphocytic leukemia (CLL). There is limited information however on ROR1 in melanoma. In the present study we analysed in seven melanoma cell lines ROR1 expression and phosphorylation as well as the effects of anti-ROR1 monoclonal antibodies (mAbs) and ROR1 suppressing siRNA on cell survival. ROR1 was overexpressed at the protein level to a varying degree and phosphorylated at tyrosine and serine residues. Three of our four self-produced anti-ROR1 mAbs (clones 3H9, 5F1 and 1A8) induced a significant direct apoptosis of the ESTDAB049, ESTDAB112, DFW and A375 cell lines as well as cell death in complement dependent cytotoxicity (CDC) and antibody dependent cellular cytotoxicity (ADCC). The ESTDAB081 and 094 cell lines respectively were resistant to direct apoptosis of the four anti-ROR1 mAbs alone but not in CDC or ADCC. ROR1 siRNA transfection induced downregulation of ROR1 expression both at mRNA and protein levels proceeded by apoptosis of the melanoma cells (ESTDAB049, ESTDAB112, DFW and A375) including ESTDAB081, which was resistant to the direct apoptotic effect of the mAbs. The results indicate that ROR1 may play a role in the survival of melanoma cells. The surface expression of ROR1 on melanoma cells may support the notion that ROR1 might be a suitable target for mAb therapy.

Gene expression analysis reveals marked differences in the transcriptome of infantile hemangioma endothelial cells compared to normal dermal microvascular endothelial cells

Background

Infantile hemangiomas are benign vascular tumors primarily found on the skin in 10% of the pediatric population. The etiology of this disease is largely unknown and while large scale genomic studies have examined the transcriptomes of infantile hemangioma tumors as a whole, no study to date has compared the global gene expression profiles of pure infantile hemangioma endothelial cells (HEMECs) to that of normal human dermal microvascular endothelial cells (HDMVECs).

Methods

To shed light on the molecular differences between these normal and aberrant dermal endothelial cell types, we performed whole genome microarray analysis on purified cultures of HEMECs and HDMVECs. We then utilized qPCR and immunohistochemistry to confirm our microarray results.

Results

Our array analysis identified 125 genes whose expression was upregulated and 104 genes whose expression was downregulated by greater than two fold in HEMECs compared to HDMVECs. Bioinformatics analysis revealed three major classifications of gene functions that were altered in HEMECs including cell adhesion, cell cycle, and arachidonic acid production. Several of these genes have been reported to be critical regulators and/or mutated in cancer, vascular tumors, and vascular malformations. We confirmed the expression of a subset of these differentially expressed genes (ANGPT2, ANTXR1, SMARCE1, RGS5, CTAG2, LTBP2, CLDN11, and KISS1) using qPCR and utilized immunohistochemistry on a panel of paraffin embedded infantile hemangioma tumor tissues to demonstrate that the cancer/testis antigen CTAG2 is highly abundant in vessel-dense proliferating infantile hemangiomas and with significantly reduced levels during tumor involution as vascular density decreases.

Conclusion

Our data reveal that the transcriptome of HEMECs is reflective of a pro-proliferative cell type with altered adhesive characteristics. Moveover, HEMECs show altered expression of many genes that are important in the progression and prognosis of metastatic cancers.

Bi-specific TCR-anti CD3 redirected T-cell targeting of NY-ESO-1- and LAGE-1-positive tumors

NY-ESO-1 and LAGE-1 are cancer testis antigens with an ideal profile for tumor immunotherapy, combining up-regulation in many cancer types with highly restricted expression in normal tissues and sharing a common HLA-A*0201 epitope, 157–165. Here, we present data to describe the specificity and anti-tumor activity of a bifunctional ImmTAC, comprising a soluble, high-affinity T-cell receptor (TCR) specific for NY-ESO-1_157–165 fused to an anti-CD3 scFv. This reagent, ImmTAC-NYE, is shown to kill HLA-A2, antigen-positive tumor cell lines, and freshly isolated HLA-A2- and LAGE-1-positive NSCLC cells. Employing time-domain optical imaging, we demonstrate in vivo targeting of fluorescently labelled high-affinity NYESO-specific TCRs to HLA-A2-, NY-ESO-1_157–165-positive tumors in xenografted mice. In vivo ImmTAC-NYE efficacy was tested in a tumor model in which human lymphocytes were stably co-engrafted into NSG mice harboring tumor xenografts; efficacy was observed in both tumor prevention and established tumor models using a GFP fluorescence readout. Quantitative RT-PCR was used to analyze the expression of both NY-ESO-1 and LAGE-1 antigens in 15 normal tissues, 5 cancer cell lines, 10 NSCLC, and 10 ovarian cancer samples. Overall, LAGE-1 RNA was expressed at a greater frequency and at higher levels than NY-ESO-1 in the tumor samples. These data support the clinical utility of ImmTAC-NYE as an immunotherapeutic agent for a variety of cancers.

Autoantibodies as biomarkers for ovarian cancer

Ovarian cancer (OVCA) has the highest mortality of all gynecologic cancers. The poor survival rate is due to the lack of diagnostic screening tests and high incidence of recurrence in OVCA patients resistant to chemotherapy that leads to a more aggressive form of the disease. Therefore, a search for biomarkers holds great promise not only for early detection of OVCA at presymptomatic stage and for monitoring the course of the disease during the first-line chemotherapy treatment but also for identifying those women whose disease is likely to recur. Research efforts have sought to unravel the complexity of the tumor specific proteome by profiling immune responses generated against tumor associated antigens (TAAs) using multianalyte-based analytical discovery platforms readily adaptable to clinical diagnostic screening tests. The occurrence of tumor-specific autoantibodies directed to respective TAAs can be observed before the development of clinical symptoms. Evaluation of the level of tumor autoantibodies during the time of tumor debulking followed by first-line chemotherapy for the prediction of early recurrence as well as their correlation with other clinical parameters to evaluate their prognostic value has been conducted in various clinical studies. The anti-tumor immune response against OVCA is the ultimate key to the development of multiple immune-based therapeutic strategies that have been proposed and tested in different clinical trials that may have beneficial impact on the disease outcome in OVCA patients.

NY-ESO-1 cancer testis antigen demonstrates high immunogenicity in triple negative breast cancer

PURPOSE

NY-ESO-1 cancer testis (CT) antigen is an attractive candidate for immunotherapy as a result of its high immunogenicity. The aim of this study was to explore the potential for NY-ESO-1 antigen directed immunotherapy in triple negative breast cancer (TNBC) by determining the frequency of expression by immunohistochemistry (IHC) and the degree of inherent immunogenicity to NY-ESO-1.

EXPERIMENTAL DESIGN

168 TNBC and 47 ER+/HER2- primary breast cancer specimens were used to determine NY-ESO-1 frequency by IHC. As previous studies have shown that patients with a robust innate humoral immune response to CT antigens are more likely to develop CD8 T-cell responses to NY-ESO-1 peptides, we evaluated the degree to which patients with NY-ESO-1 expression had inherent immunogenicity by measuring antibodies. The relationship between NY-ESO-1 expression and CD8+ T lymphocytes was also examined.

RESULTS

The frequency of NY-ESO-1 expression in the TNBC cohort was 16% versus 2% in ER+/HER2- patients. A higher NY-ESO-1 score was associated with a younger age at diagnosis in the TNBC patients with NY-ESO-1 expression (p = 0.026). No differences in OS (p = 0.278) or PFS (p = 0.238) by NY-ESO-1 expression status were detected. Antibody responses to NY-ESO-1 were found in 73% of TNBC patients whose tumors were NY-ESO-1 positive. NY-ESO-1 positive patients had higher CD8 counts than negative patients (p = 0.018).

CONCLUSION

NY-ESO-1 is expressed in a substantial subset of TNBC patients and leads to a high humoral immune response in a large proportion of these individuals. Given these observations, patients with TNBC may benefit from targeted therapies directed against NY-ESO-1.

Pattern of cancer/testis antigen expression in lung cancer patients

Cancer/testis (CT) antigens represent promising targets for immunotherapy. We investigated the composite expression of 13 CT antigens by RT-PCR in 79 lung cancer tissues and by immunohistochemistry in 22 lung cancer tissues. In the 79 lung cancer tissues, MAGE-3 (42%) was expressed most frequently and followed by NY-SAR-35 (33%), NY-ESO-1 (30%), MAGE-1 (27%), CT-7 (20%), MAGE-4 (19%), LAGE-1 (16%), and MAGE-10 (14%). Twenty-one tissues did not express any of the CT antigens tested, 58 (73%) expressed at least one, 36 (46%) co-expressed two, 24 (30%) co-expressed three, 17 (22%) co-expressed four, 14 (18%) co-expressed five, 8 (10%) co-expressed six, 4 (6%) co-expressed seven and 2 tissues expressed 9 of the 13 examined CT antigens. Expression of CT antigens was significantly associated with age (P<0.001), smoking history (P=0.009), and gender (P=0.001) of patients, whereas no correlation was found between the expression of CT antigens and other clinical factors, such as pT status, pN status, tumor stage, and histology history. The present results show that CT antigens are potential candidates in lung cancer patients for polyvalent immunotherapy.

Silencing of cancer-germline genes in human preimplantation embryos: evidence for active de novo DNA methylation in stem cells

Several human germline-specific genes rely principally on DNA methylation for repression in somatic tissues. Many of these genes, including MAGEA1, were qualified as cancer-germline (CG), as they become activated in tumors, where losses of DNA methylation are common. The developmental stage at which CG genes acquire DNA methylation marks is unknown. Here, we show that in human preimplantation embryos, transcription of CG genes increases up to the morula stage, and then decreases dramatically in blastocysts, suggesting that CG gene silencing occurs in blastocyst stem cells. Consistently, transfection studies with MAGEA1 constructs in embryonal carcinoma (EC) cells, which represent a malignant surrogate of blastocyst-derived stem cells, revealed active repression and marked de novo methylation of MAGEA1 transgenes in these cells. Active repression of the endogenous MAGEA1 gene in human EC cells was evidenced by its rapid re-silencing following prior induction with a DNA methylation inhibitor. Moreover, de novo DNA methyltransferases DNMT3A and DNMT3B appeared to contribute to the silencing of MAGEA1 and other CG genes in EC cells. Altogether our data indicate that CG genes like MAGEA1 are programmed for repression in the blastocyst, and suggest that de novo DNA methylation is a key event in this process.

Epigenetic alterations associated with cellular senescence: a barrier against tumorigenesis or a red carpet for cancer?

Cellular senescence is eminently characterized by a permanent cell cycle arrest and the acquisition of morphological, physiological and epigenetic changes. The establishment of cellular senescence can occur in response to telomere attrition associated with cell turnover and ageing or following oncogene activation. Although seemingly two distinct phenomena, cellular senescence and cancer share similarly altered global epigenetic profiles comprising changes in DNA methylation, involving global hypomethylation of repetitive DNA sequences and regional hypermethylation of some gene promoters, and in histone post-translational modifications. As epigenetic and genetic alterations are likely to act synergistically in cancer, anomalous epigenetic marks acquired during ageing or in response to oncogene activation might play important roles in tumorigenesis and cancer progression. These potentially tumor-promoting epigenetic alterations include transcriptional repression of genes encoding tumor suppressors or developmentally regulated proteins, expression of non-coding repetitive RNAs and acquisition of distinct heterochromatin marks that may contribute to suppress cell death by reducing DNA damage response. Cellular senescence may thus be viewed as a double-edged sword that, although acting as a potent anti-proliferative barrier, may pave the way to tumorigenesis in senescence-escaping cells by altering their epigenetic make up.

Polymeric structure and host Toll-like receptor 4 dictate immunogenicity of NY-ESO-1 antigen in vivo

In search of intrinsic factors that contribute to the distinctively strong immunogenicity of a non-mutated cancer/testis antigen, we found that NY-ESO-1 forms polymeric structures through disulfide bonds. NY-ESO-1 binding to immature dendritic cells was dependent on its polymeric structure and involved Toll-like receptor-4 (TLR4) on the surface of immature dendritic cells in mouse and human. Gene gun-delivered plasmid encoding the wild-type NY-ESO-1 readily induced T cell-dependent antibody (Ab) responses in wild-type C57BL/10 mice but not TLR4-knock-out C57BL/10ScNJ mice. Disrupting polymeric structures of NY-ESO-1 by cysteine-to-serine (Cys-to-Ser) substitutions lead to diminished immunogenicity and altered TLR4-dependence in the induced Ab response. To demonstrate its adjuvant effect, NY-ESO-1 was fused with a major mugwort pollen allergen Art v 1 and a tumor-associated antigen, carbonic anhydrase 9. Plasmid DNA vaccines encoding the fusion genes generated robust immune responses against otherwise non-immunogenic targets in mice. Polymeric structure and TLR4 may play important roles in rendering NY-ESO-1 immunogenic and thus serve as a potent molecular adjuvant. NY-ESO-1 thus represents the first example of a cancer/testis antigen that is a also damage-associated molecular pattern.

Cancer testis antigens: novel biomarkers and targetable proteins for ovarian cancer

Ovarian cancer is the fifth leading cause of cancer death in women and the leading cause from gynecological malignancies. Despite the recently improved outcomes of new chemotherapeutical agents in the therapy of ovarian cancer and the increased 5-year survival rate, the mortality of this malignancy disease remains unchanged. Ovarian cancer therapy is often correlated to the stage of the tumor, but the first step is usually surgical treatment. Afterward, various courses of chemotherapy and radiation are suggested. Obviously, the higher the developmental stage of the tumor, the less the probability is in eradicating it surgically, especially in relation to metastasis. It is clear that an early diagnosis of ovarian cancer is important for the survival of these patients. In order to identify ovarian cancer patients in the early stages, a number of studies are focusing on a particular class of antigens called cancer testis antigens. These antigens display high expression in tumors of different histology, but are normally restricted to the testis and have low or no expression in normal tissues. The testes are an immunologically-privileged site due to the presence of tight junctions between adjacent Sertoli cells that constitute the blood-testis barrier, which prevents auto-immune reactions. In the past few years, some of these antigens were demonstrated to be very promising for the early diagnosis and development of vaccines for ovarian cancer. This review aims to underline the most reliable cancer testis antigens under investigation at this moment.

MAGE-C2/CT10 protein expression is an independent predictor of recurrence in prostate cancer

The cancer-testis (CT) family of antigens is expressed in a variety of malignant neoplasms. In most cases, no CT antigen is found in normal tissues, except in testis, making them ideal targets for cancer immunotherapy. A comprehensive analysis of CT antigen expression has not yet been reported in prostate cancer. MAGE-C2/CT-10 is a novel CT antigen. The objective of this study was to analyze extent and prognostic significance of MAGE-C2/CT10 protein expression in prostate cancer. 348 prostate carcinomas from consecutive radical prostatectomies, 29 castration-refractory prostate cancer, 46 metastases, and 45 benign hyperplasias were immunohistochemically analyzed for MAGE-C2/CT10 expression using tissue microarrays. Nuclear MAGE-C2/CT10 expression was identified in only 3.3% primary prostate carcinomas. MAGE-C2/CT10 protein expression was significantly more frequent in metastatic (16.3% positivity) and castration-resistant prostate cancer (17% positivity; p<0.001). Nuclear MAGE-C2/CT10 expression was identified as predictor of biochemical recurrence after radical prostatectomy (p = 0.015), which was independent of preoperative PSA, Gleason score, tumor stage, and surgical margin status in multivariate analysis (p<0.05). MAGE-C2/CT10 expression in prostate cancer correlates with the degree of malignancy and indicates a higher risk for biochemical recurrence after radical prostatectomy. Further, the results suggest MAGE-C2/CT10 as a potential target for adjuvant and palliative immunotherapy in patients with prostate cancer.

Cancer/testis (CT) antigens, carcinogenesis and spermatogenesis

During spermatogenesis, spermatogonial stem cells, undifferentiated and differentiated spermatogonia, spermatocytes, spermatids and spermatozoa all express specific antigens, yet the functions of many of these antigens remain unexplored. Studies in the past three decades have shown that many of these transiently expressed genes in developing germ cells are proto-oncogenes and oncogenes, which are expressed only in the testis and various types of cancers in humans and rodents. As such, these antigens are designated cancer/testis antigens (CT antigens). Since the early 1980s, about 70 families of CT antigens have been identified with over 140 members are known to date. Due to their restricted expression in the testis and in various tumors in humans, they have been used as the target of immunotherapy. Multiple clinical trials at different phases are now being conducted with some promising results. Interestingly, in a significant number of cancer patients, antibodies against some of these CT antigens were detected in their sera. However, antibodies against these CT antigens in humans under normal physiological conditions have yet to be reported even though many of these antigens are residing outside of the blood-testis barrier (BTB), such as in the basal compartment of the seminiferous epithelium and in the stem cell niche in the testis. In this review, we summarize latest findings in the field regarding several selected CT antigens which may be intimately related to spermatogenesis due to their unusual restricted expression during different discrete events of spermatogenesis, such as cell cycle progression, meiosis and spermiogenesis. This information should be helpful to investigators in the field to study the roles of these oncogenes in spermatogenesis.

Insights into the processing of MHC class I ligands gained from the study of human tumor epitopes

The molecular definition of tumor antigens recognized by cytolytic T lymphocytes (CTL) started in the late 1980s, at a time when the MHC class I antigen processing field was in its infancy. Born together, these two fields of science evolved together and provided each other with critical insights. Over the years, stimulated by the potential interest of tumor antigens for cancer immunotherapy, scientists have identified and characterized numerous antigens recognized by CTL on human tumors. These studies have provided a wealth of information relevant to the mode of production of antigenic peptides presented by MHC class I molecules. A number of tumor antigenic peptides were found to result from unusual mechanisms occurring at the level of transcription, translation or processing. Although many of these mechanisms occur in the cell at very low level, they are relevant to the immune system as they determine the killing of tumor cells by CTL, which are sensitive to low levels of peptide/MHC complexes. Moreover, these unusual mechanisms were found to occur not only in tumor cells but also in normal cells. Thereby, the study of tumor antigens has illuminated many aspects of MHC class I processing. We review here those insights into the MHC I antigen processing pathway that result from the characterization of human tumor antigens recognized by CTL.

Is antigen specificity the key to efficient adoptive T-cell therapy?

Adoptive transfer of T cells remains a promising approach in melanoma. Initial clinical trials performed with polyclonal tumor-infiltrating lymphocyte gave limited clinical results. Nonetheless, encouraging results have been reported in adjuvant setting (stage III melanoma), and when tumor-infiltrating lymphocytes were associated with lymphodepleting regimens. Specificity of adoptive cell therapy has been achieved with the infusion of antigen specific cytotoxic T-lymphocyte clones, associated with some clinical responses. Antigen specificity can also be obtained by the allogeneic transfer of high-avidity T-cell receptors into autologous T cells. We propose an alternative strategy based on the selection of antigen-specific T cells with magnetic beads coated with HLA–peptide multimers. Future improvements of adoptive melanoma immunotherapy may be achieved by its association with other therapeutic strategies such as targeted therapy against signaling pathways.

Role of gene methylation in antitumor immune response: implication for tumor progression

Cancer immunosurveillance theory has emphasized the role of escape mechanisms in tumor growth. In this respect, a very important factor is the molecular characterization of the mechanisms by which tumor cells evade immune recognition and destruction. Among the many escape mechanisms identified, alterations in classical and non-classical HLA (Human Leucocyte Antigens) class I and class II expression by tumor cells are of particular interest. In addition to the importance of HLA molecules, tumor-associated antigens and accessory/co-stimulatory molecules are also involved in immune recognition. The loss of HLA class I antigen expression and of co-stimulatory molecules can occur at genetic, transcriptional and post-transcriptional levels. Epigenetic defects are involved in at least some mechanisms that preclude mounting a successful host-antitumor response involving the HLA system, tumor-associated antigens, and accessory/co-stimulatory molecules. This review summarizes our current understanding of the role of methylation in the regulation of molecules involved in the tumor immune response.

The biology of cancer testis antigens: putative function, regulation and therapeutic potential

Cancer testis antigens (CTA) are a large family of tumor-associated antigens expressed in human tumors of different histological origin, but not in normal tissues except for testis and placenta. This tumor-restricted pattern of expression, together with their strong in vivo immunogenicity, identified CTA as ideal targets for tumor-specific immunotherapeutic approaches, and prompted the development of several clinical trials of CTA-based vaccine therapy. Driven by this practical clinical interest, a more detailed characterization of CTA biology has been recently undertaken. So far, at least 70 families of CTA, globally accounting for about 140 members, have been identified. Most of these CTA are expressed during spermatogenesis, but their function is still largely unknown. Epigenetic events, particularly DNA methylation, appear to be the primary mechanism regulating CTA expression in both normal and transformed cells, as well as in cancer stem cells. In view of the growing interest in CTA biology, the aim of this review is to provide the most recent information on their expression, regulation and function, together with a brief summary of the major clinical trials involving CTA as therapeutic agents. The pharmacologic modulation of CTA expression profiles on neoplastic cells by DNA hypomethylating drugs will also be discussed as a feasible approach to design new combination therapies potentially able to improve the clinical efficacy of currently adopted CTA-based immunotherapeutic regimens in cancer patients.

Epitope hierarchy of spontaneous CD4+ T cell responses to LAGE-1

NY-ESO-1 and LAGE-1 represent highly homologous cancer-germline Ags frequently coexpressed by many human cancers, but not by normal tissues, except testis. In contrast to NY-ESO-1, little is known about spontaneous immune responses to LAGE-1. In the current study, we report on spontaneous LAGE-1-specific CD4(+) T cells isolated from PBLs of patients with advanced LAGE-1(+)/NY-ESO-1(+) melanoma and directed against three promiscuous and immunodominant epitopes. Strikingly, although the three LAGE-1-derived epitopes are highly homologous to NY-ESO-1-derived epitopes, LAGE-1-specific CD4(+) T cells did not cross-react with NY-ESO-1. LAGE-1-specific CD4(+) T cells produced Th1-type and/or Th2-type cytokines and did not exert inhibitory effects on allogenic T cells. We observed that most patients with spontaneous NY-ESO-1-specific responses exhibited spontaneous CD4(+) T cell responses to at least one of the three immunodominant LAGE-1 epitopes. Additionally, nearly half of the patients with spontaneous LAGE-1-specific CD4(+) T cell responses had circulating LAGE-1-specific Abs that recognized epitopes located in the C-terminal portion of LAGE-1, which is distinct from NY-ESO-1. Collectively, our findings define the hierarchy of immunodominance of spontaneous LAGE-1-specific CD4(+) T cell responses in patients with advanced melanoma. These findings demonstrate the capability of LAGE-1 to stimulate integrated cellular and humoral immune responses that do not cross-react with NY-ESO-1. Therefore, they provide a strong rationale for the inclusion of LAGE-1 peptides or protein in vaccine trials for patients with NY-ESO-1(+)/LAGE-1(+) tumors.

Cancer/testis (CT) antigens: potential targets for immunotherapy

Cancer/testis (CT) antigens are protein antigens with normal expression restricted to adult testicular germ cells, and yet are aberrantly activated and expressed in a proportion of various types of human cancer. At least a subset of this group of antigens has been found to elicit spontaneous humoral and cell-mediated immune responses in cancer patients, raising the possibility that these antigens could be cancer vaccine targets. More than 100 CT antigen genes have been reported in the literature, with approximately 30 being members of multigene families on the X chromosome, so-called CT-X genes. Most CT-X genes are expressed at the spermatogonia stage of spermatogenesis, and their functions are mostly unknown. In cancer, the frequency of CT antigen expression is highly variable among different tumor types, but is more often expressed in high-grade late-stage cases in general. Cancer vaccine trials based on CT antigens MAGE-A3 and NY-ESO-1 are currently ongoing, and these antigens may also play a role in antigen-specific adoptive T-cell transfer and in the immunomodulation approach of cancer therapy.

A Mage3/Heat Shock Protein70 DNA vaccine induces both innate and adaptive immune responses for the antitumor activity

Heat shock proteins (HSPs) are highly effective and versatile molecules in promoting antitumor immune responses. We tested whether a HSP-based DNA vaccine can induce effective immune response against Mage3, a cancer testis (CT) antigen frequently expressed in many human tumors, thereby controlling the Mage3-expressing tumor. The vaccine was constructed by linking human inducible HSP70 to the C-terminus of a modified Mage3 gene (sMage3) that was attached at its N-terminus with the signal leader sequence of the human RANTES for releasing the expressed fusion protein from the transduced cells. Intramuscular injection of sMage3Hsp DNA induced CD4(+)/CD8(+) T cell and antibody responses. Vaccination with sMage3Hsp DNA was more effective in inhibiting Mage3-expressing TC-1 tumors. When we dissected the antitumor activity of CD4(+) and CD8(+) T cells by immunizing CD4(+) and CD8(+) knockout mice with sMage3Hsp DNA, we found that both CD8(+) T and CD4(+) T cells played a role in control of inoculated tumor, but did not constitute the whole of immune protection in the prophylactic immunization. Instead, depletion of natural killer (NK) cells led to a major loss of antitumor activity in the immunized mice. These results indicate that the HSP-based Mage3 DNA vaccine can more effectively inhibit tumor growth by inducing both the innate immune responses and Mage3-specific adaptive immune responses via the Hsp-associated adjuvant function.