Expression of multiple cancer-testis antigen genes in gastrointestinal and breast carcinomas

Decreased Expression of PLD2 Promotes EMT in Colorectal Cancer Invasion and Metastasis

Background and Objectives: PLD2 has been identified as playing a critical role in cancer cell motility and migration and other pathophysiological processes. We investigated the expression of PLD2 and its biological functions and clinical implications in human colorectal cancer. Materials and Methods: In this study, the expressions of PLD2 were analyzed in CRC cell lines and CRC samples by RT-PCR, western blot and immunohistochemistry. The PLD enzyme activity was studied using an PLD detection kit. We also performed matrigel invasion assay to evaluate the invasive capabilities in CRC cells. The expressions of EMT-related markers were quantified at mRNA and protein level using RT-PCR and western blot. We performed high-throughput RNA sequencing on PLD2 knockdown and overexpression CRC cell lines to explore the changes in gene expression associated with PLD2. Result: Herein, we showed that PLD2 expression was relatively low in CRC cell lines and CRC samples and PLD2 deficiency was significantly correlated with more advanced clinical phenotype regarding lymphatic and distant metastasis and poor patient survival. We also detected that PLD2 knockdown favored epithelial-mesenchymal transition (EMT) and thus promoted CRC invasion and metastasis. Further exploration uncovered that the expressions of several important genes closely related to metabolic pathways in CRC were noticeably altered due to PLD2 deficiency, including ID1, IFIT4, OASL, IFIT2 and CTAG2. Conclusion: Our results revealed that PLD2 deficiency promotes cell invasion and metastasis in CRC via EMT indicating PLD2 might have an important implication in carcinogenesis and progression and would be a new therapeutic target for cancer treatment.

Gene of the month: cancer testis antigen gene 1b (NY-ESO-1)

Cancer testis antigen gene 1B (CTAG1B) and its associated gene product; New York oesophageal squamous carcinoma 1 (NY-ESO-1), represent a unique and promising target for cancer immunotherapy. As a member of the cancer testis antigen family (CTA), the protein's restricted expression pattern and ability to elicit spontaneous humoural and cellular immune responses has resulted in a plethora of novel modalities and approaches attempting to harness its immunotherapeutic anti-cancer potential. Here, we discuss the structure and function of CTAG1B/NY-ESO-1 in both health and disease, immunohistochemical detection, as well as the most promising advances in the development of associated anti-cancer therapies. From cancer vaccines to engineered cellular therapy approaches, a multitude of immunotherapies targeting CTA's are coming to the forefront of oncology. Although the efficacy of such approaches have yet to provide convincing evidence of durable response, early phase clinical trial data has resulted in some exciting findings which will have significant potential to act as a platform for future practice changing technologies.

Serine protease PRSS56, a novel cancer-testis antigen activated by DNA hypomethylation, promotes colorectal and gastric cancer progression via PI3K/AKT axis

BACKGROUND

Cancer/testis (CT) antigens/genes are usually overexpressed in cancers and exhibit high immunogenicity, making them promising targets for immunotherapy and cancer vaccines. The role of serine protease PRSS56 in cancers remains unknown to date.

METHODS

RNA sequencing studies were performed to screen CT genes in gastric cancer (GC) and colorectal cancer (CRC) cells exposed to DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-AZA-CdR). Bioinformatics analysis was conducted to analyze the correlation between PRSS56 expression and DNA methylation. Functional experiments were performed to explore the biological function of PRSS56 in GC and CRC.

RESULTS

In this study, we identified the testis-specific serine proteases PRSS56 as a novel CT antigen. PRSS56 was frequently overexpressed in various cancers, especially in gastrointestinal cancer. PRSS56 expression was negatively associated with promoter DNA methylation level, and positively associated with gene body methylation level. PRSS56 expression was significantly activated in colorectal and gastric cancer cells exposed to DNA methyltransferase inhibitors. Importantly, our finding highlights that the decreased methylation level of the CpG site cg10242318 in the PRSS56 promoter region resulted in its overexpression in GC and CRC. Additionally, functional assays verified that PRSS56 overexpression activated PI3K-AKT signaling in GC and CRC.

CONCLUSION

Serine protease PRSS56 is a novel CT antigen that is reactivated in cancers by promoter DNA hypomethylation. PRSS56 functions oncogenic roles in GC and CRC by activating of PI3K/AKT axis. Our results presented here represent the first data on the function of the serine protease PRSS56 in cancers.

The therapeutic potential value of Cancer-testis antigens in immunotherapy of gastric cancer

Gastric cancer (GC) is the fourth most common cause of mortality and the fifth for incidence, globally. Diagnosis, early prognosis, and therapy remains challenging for this condition, and new tumor-associated antigens are required for its detection and immunotherapy. Cancer-testis antigens (CTAs) are a subfamily of tumor-associated antigens (TAAs) that have been identified as potential biomarkers and targets for cancer immunotherapy. The CTAs-restricted expression pattern in tumor cells and their potential immunogenicity identify them as attractive target candidates in CTA-based diagnosis or prognosis or immunotherapy. To date, numerous studies have reported the dysregulation of CTAs in GC. Several clinical trials have been done to assess CTA-based immunotherapeutic potential in the treatment of GC patients. NY-ESO-1, MAGE, and KK-LC-1 have been used in GC clinical trials. We review recent studies that have investigated the potential of the CTAs in GC regarding the expression, function, aggressive phenotype, prognosis, and immunological responses as well as their possible clinical significance as immunotherapeutic targets with a focus on challenges and future interventions.

Multi-antigen-targeted T-cell therapy to treat patients with relapsed/refractory breast cancer

Purpose

Adoptively transferred, ex vivo expanded multi-antigen-targeted T cells (multiTAA-T) represent a new, potentially effective, and nontoxic therapeutic approach for patients with breast cancer (BC). In this first-in-human trial, we investigated the safety and clinical effects of administering multiTAA T cells targeting the tumor-expressed antigens, Survivin, NY-ESO-1, MAGE-A4, SSX2, and PRAME, to patients with relapsed/refractory/metastatic BC.

Materials and methods

MultiTAA T-cell products were generated from the peripheral blood of heavily pre-treated patients with metastatic or locally recurrent unresectable BC of all subtypes and infused at a fixed dose level of 2 × 107/m2. Patients received two infusions of cells 4 weeks apart and safety and clinical activity were determined. Cells were administered in an outpatient setting and without prior lymphodepleting chemotherapy.

Results

All patients had estrogen receptor/progesterone receptor positive BC, with one patient also having human epidermal growth factor receptor 2-positive. There were no treatment-related toxicities and the infusions were well tolerated. Of the 10 heavily pre-treated patients enrolled and infused with multiTAA T cells, nine had disease progression while one patient with 10 lines of prior therapies experienced prolonged (5 months) disease stabilization that was associated with the in vivo expansion and persistence of T cells directed against the targeted antigens. Furthermore, antigen spreading and the endogenous activation of T cells directed against a spectrum of non-targeted tumor antigens were observed in 7/10 patients post-multiTAA infusion.

Conclusion

MultiTAA T cells were well tolerated and induced disease stabilization in a patient with refractory BC. This was associated with in vivo T-cell expansion, persistence, and antigen spreading. Future directions of this approach may include additional strategies to enhance the therapeutic benefit of multiTAA T cells in patients with BC.

Meiotic Genes and DNA Double Strand Break Repair in Cancer

Tumor cells show widespread genetic alterations that change the expression of genes driving tumor progression, including genes that maintain genomic integrity. In recent years, it has become clear that tumors frequently reactivate genes whose expression is typically restricted to germ cells. As germ cells have specialized pathways to facilitate the exchange of genetic information between homologous chromosomes, their aberrant regulation influences how cancer cells repair DNA double strand breaks (DSB). This drives genomic instability and affects the response of tumor cells to anticancer therapies. Since meiotic genes are usually transcriptionally repressed in somatic cells of healthy tissues, targeting aberrantly expressed meiotic genes may provide a unique opportunity to specifically kill cancer cells whilst sparing the non-transformed somatic cells. In this review, we highlight meiotic genes that have been reported to affect DSB repair in cancers derived from somatic cells. A better understanding of their mechanistic role in the context of homology-directed DNA repair in somatic cancers may provide useful insights to find novel vulnerabilities that can be targeted.

NY-ESO-1 expression in sarcomas: A diagnostic marker and immunotherapy target

NY-ESO-1 (CTAG 1B) is highly expressed in the majority of synovial sarcomas and myxoid/round cell liposarcomas as well as in a subset of melanomas, but only rarely in other mesenchymal tumors. This points to a potential for using NY-ESO-1 in the differential diagnosis of these lesions. Furthermore, promising results have been obtained in clinical trials testing NY-ESO-1-targeted immunotherapy in subsets of melanoma and synovial sarcoma patients.

Synaptonemal complex proteins modulate the level of genome integrity in cancers

The synaptonemal complex (SC) is a proteinaceous structure that is transiently formed during meiosis to promote homologous recombination between maternal and paternal chromosomes. As this structure is required only for meiotic recombination, the proteins constituting the complex are almost undetectable in normal somatic cells, but they can be expressed under the conditions in which the transcriptional machinery is deregulated. Accumulating evidence indicates that they are epigenetically expressed in cancers of various origin. Not surprisingly, in contrast to their meiotic roles, the somatic roles of the SC proteins remain to be investigated. However, it has recently been reported that SYCP3 and SYCE2 control DNA double‐strand break repair negatively and positively, respectively, suggesting that the ectopic expression of the SC proteins in somatic cells could be associated with the maintenance of genomic instability. Thus, it is highly likely that the investigation of the somatic roles of the SC proteins would improve our understanding of the mechanisms underlying tumor development.

Novel Insights Into Epigenetic Reprogramming and Destabilization of Pericentromeric Heterochromatin in Cancer

Pericentromeric heterochromatin is maintained in a condensed structure by repressive epigenetic control mechanisms and perturbation of these may cause diseases. The chromosome 1q12 region harbors the largest pericentromeric heterochromatin domain in the genome and is among the most common breakpoints in both solid and hematopoietic cancers. Furthermore, the 1q arm is frequently amplified in cancer and this may support tumorigenesis by increasing the dosage of the many oncogenes of this genomic region. Recent studies have provided insight into the mechanisms leading to loss of 1q12 stability and 1q amplification and DNA hypomethylation seems to play a prominent role. This may be the result of decreased activity of DNA methyltransferases and instrumental for 1q12 destabilization or arise secondary to perturbation of other important epigenetic mechanisms that control repression of pericentromeric heterochromatin. Polycomb proteins were recently demonstrated to epigenetically reprogram demethylated 1q12 pericentromeric heterochromatin in premalignant and malignant cells to form large subnuclear structures known as polycomb bodies. This may influence the regulation and stability of 1q12 pericentromeric heterochromatin and/or the distribution of polycomb factors to support tumorigenesis. This review will discuss recent insight into the epigenetic perturbations causing the destabilization of 1q12 pericentromeric heterochromatin and its possible implications for tumor biology.

Efficacy of co-immunization with the DNA and peptide vaccines containing SYCP1 and ACRBP epitopes in a murine triple-negative breast cancer model

Multiepitope cancer vaccines have gained lots of attention for prophylactic and therapeutic purposes in cancer patients. In our previous study, multiepitope DNA and peptide cancer vaccines consisted of the most immunodominant epitopes of ACRBP and SYCP1 antigens were designed by bioinformatic tools. In this study, the effect of prophylactic co-immunization with these DNA and peptide cancer vaccines in the 4T1 breast cancer animal model was assessed. Serum levels of the peptide-specific IgG total, IgG2a and IgG1 were measured by enzyme-linked immunosorbent assay (ELISA). Also, the efficacy of the immunized mice splenocytes' for producing interleukin-4 (IL-4) and interferon-γ (IFN-γ) was evaluated. The co-immunization caused a significant (P < .05) increase in the serum levels of IgG1 and IgG2a. The co-immunized mice splenocytes exhibited significantly enhanced IL-4 (6.6-fold) and IFN-γ (19-fold) production. Also, their lymphocytes exhibited higher proliferation rate (3-fold) and granzyme B production (6.5-fold) in comparison with the control. The prophylactic co-immunization significantly decreased the breast tumors' volume (78%) and increased the tumor-bearing mice survival time (37.5%) in comparison with the control. Taking together, prophylactic co-immunization with these multiepitope DNA and peptide cancer vaccines can activate the immune system against breast cancer. However, further experiments are needed to evaluate their efficacy from different angles.

The ectopic expression of meiCT genes promotes meiomitosis and may facilitate carcinogenesis

Cancer meiomitosis is defined as the concurrent activation of both mitotic and meiotic machineries in neoplastic cells that confer a selective advantage together with increased genomic instability. MeiCT (meiosis-specific cancer/testis) genes that perform specialized functions in the germline events required for the first meiotic division are ectopically expressed in several cancers. Here we describe the expression profiles of meiCT genes and proteins across a number of cancers and review the proposed mechanisms that increase aneuploidy and elicit reduction division in polyploid cells. These mechanisms are centered on the overexpression and function of meiCT proteins in cancers under various conditions that includes a response to genotoxic stress. Since meiCT genes are transcriptionally repressed in somatic cells, their target offers a promising therapeutic approach with limited toxicity to healthy tissues. Throughout the review, we provide a detailed description of the roles for each gene in the context of meiosis and we discuss proposed functions and outcomes resulting from their ectopic reactivation in cancer.

Sitagliptin affects gastric cancer cells proliferation by suppressing Melanoma-associated antigen-A3 expression through Yes-associated protein inactivation

Sitagliptin is an emerging oral hypoglycemic agent that inhibits the development of a wide variety of tumors. Current researches indicate that the abnormal activation of Yes-associated protein (YAP) promotes the proliferation and poor prognosis of multiple tumors. However, the ability of sitagliptin to regulate YAP and its effects on gastric cancer (GC) cells remain unclear. Here, we first showed that sitagliptin inhibited the proliferation of GC cells, and this inhibition was regulated by Hippo pathway. Sitagliptin phosphorylated YAP in a large tumor suppressor homolog-dependent manner, thereby inhibiting YAP nuclear translocation, and promoted YAP cytoplasm retention. This inhibition can be blocked by adenosine 5'-monophosphate-activated protein kinase (AMPK). Moreover, sitagliptin could reduce the expression of tumor-testis antigen Melanoma-associated antigen-A3 through YAP. In conclusion, sitagliptin may have a potential inhibitory effect on GC by AMPK/YAP/melanoma-associated antigen-A3 pathway.

SYCP2 expression is a novel prognostic biomarker in luminal A/B breast cancer

Aim: To explore the prognostic value of synaptonemal complex protein-2 (SYCP2) in different subtypes of breast cancer. Patients & materials: In silico bioinformatic analysis was conducted using large databases. Results: SYCP2 was only significantly upregulated in luminal B tumors compared with the adjacent normal tissues. SYCP2 expression was an independent indicator of shorter overall survival in luminal A patients (hazard ratio: 2.269; 95% CI: 1.059–4.862; p = 0.035) and luminal B patients (hazard ratio: 2.546; 95% CI: 1.020–6.355; p = 0.045). Its expression was negatively correlated with the methylation status of multiple CpG sites (cg22214414, cg23241473 and cg07347645) in both luminal A and luminal B tumors. Conclusion: Increased SYCP2 expression might be an independent indicator of shorter overall survival in both luminal A and luminal B patients.

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.

B cells in esophago-gastric adenocarcinoma are highly differentiated, organize in tertiary lymphoid structures and produce tumor-specific antibodies

Tumor-infiltrating lymphocytes (TILs) are correlated to prognosis of several kinds of cancer. Most studies focused on T cells, while the role of tumor-associated B cells (TABs) has only recently gained more attention. TABs contain subpopulations with distinct functions, potentially promoting or inhibiting immune responses. This study provides a detailed analysis of TABs in gastro-esophageal adenocarcinoma (EAC). Flow cytometric analyses of single cell suspensions of tumor samples, mucosa, lymph nodes and peripheral blood mononuclear cells (PBMC) of EAC patients and healthy controls revealed a distinct B cell compartment in cancer patients. B cells were increased in tumor samples and subset-analyses of TILs showed increased proportions of differentiated and activated B cells and an enrichment for follicular T helper cells. Confocal microscopy demonstrated that TABs were mainly organized in tertiary lymphoid structures (TLS), which resemble lymphoid follicles in secondary lymphoid organs. A panel of 34 tumor-associated antigens (TAAs) expressed in EAC was identified based on public databases and TCGA data to analyze tumor-specific B cell responses using a LUMINEXTM bead assay and flow cytometry. Structural analyses of TLS and the detection of tumor-specific antibodies against one or more TAAs in 48.1% of analyzed serum samples underline presence of anti-tumor B cell responses in EAC. Interestingly, B cells were decreased in tumors with expression of Programmed Death Ligand 1 or impaired HLA-I expression. These data demonstrate that anti-tumor B cell responses are an additional and underestimated aspect of EAC. Our results are of immediate translational relevance to emerging immunotherapies.

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.

Cancer stem cells as targets for DC-based immunotherapy of colorectal cancer

The therapy of colorectal cancer (CRC) patients is often unsuccessful because of the presence of cancer stem cells (CSCs) resistant to conventional approaches. Dendritic cells (DC)-based protocols are believed to effectively supplement CRC therapy. Our study was aimed to assess how the number and properties of CSCs isolated from tumor tissue of CRC patients will affect the biological characteristics of in vitro modified DCs. Similar procedures were conducted with the using of CRC HCT116 and HT29 cell lines. We found that the detailed configuration of CSC-like markers significantly influenced the maturation and activation of DCs after stimulation with cancer cells lysates or culture supernatants. This basic stimulatory effect was enhanced by LPS that is normally present in CRC CSCs niche. The increased number of CD29+ and CD44+ CSCs presented the opposite impact on treated DCs as showed by many significant correlations. The CD133+ CSCs seemed to impair the functions of DCs. The more CD133+ CSCs in tumor sample the lower number of activated DCs evidenced after stimulation. Moreover, our results showed superiority of the spherical culture model over the adherent one since spherical HCT116 and HT29 cells presented similar influence on DCs properties as CRC patients cancer cells. We concluded that the DCs features may depend directly on the properties of CSCs affected by progression status of tumor.

Sex-Related Differences in Lactotroph Tumor Aggressiveness Are Associated With a Specific Gene-Expression Signature and Genome Instability

Sex-related differences have been reported in various cancers, in particular men with lactotroph tumors have a worse prognosis than women. While the underlying mechanism of this sexual dimorphism remains unclear, it has been suggested that a lower estrogen receptor alpha expression may drive the sex differences observed in aggressive and malignant lactotroph tumors that are resistant to dopamine agonists. Based on this observation, we aimed to explore the molecular importance of the estrogen pathway through a detailed analysis of the transcriptomic profile of lactotroph tumors from 20 men and 10 women. We undertook gene expression analysis of the selected lactotroph tumors following their pathological grading using the five-tiered classification. Chromosomic alterations were further determined in 13 tumors. Functional analysis showed that there were differences between tumors from men and women in gene signatures associated with cell morphology, cell growth, cell proliferation, development, and cell movement. Hundred-forty genes showed an increased or decreased expression with a minimum 2-fold change. A large subset of those genes belonged to the estrogen receptor signaling pathway, therefore confirming the potent role of this pathway in lactotroph tumor sex-associated aggressiveness. Genes belonging to the X chromosome, such as CTAG2, FGF13, and VEGF-D, were identified as appealing candidates with a sex-linked dysregulation in lactotroph tumors. Through our comparative genomic hybridization analyses (CGH), chromosomic gain, in particular chromosome 19p, was found only in tumors from men, while deletion of chromosome 11 was sex-independent, as it was found in most (5/6) of the aggressive and malignant tumors. Comparison of transcriptomic and CGH analysis revealed four genes (CRB3, FAM138F, MATK, and STAP2) located on gained regions of chromosome 19 and upregulated in lactotroph tumors from men. MATK and STAP2 are both implicated in cell growth and are reported to be associated with the estrogen signaling pathway. Our work confirms the proposed involvement of the estrogen signaling pathway in favoring the increased aggressiveness of lactotroph tumors in men. More importantly, we highlight a number of ER-related candidate genes and further identify a series of target molecules with sex-specific expression that could contribute to the aggressive behavior of lactotroph tumors in men.

Early gastric cancer frequently has high expression of KK-LC-1, a cancer-testis antigen

AIM

To assess cancer-testis antigens (CTAs) expression in gastric cancer patients and examined their associations with clinicopathological factors.

METHODS

Eighty-three gastric cancer patients were evaluated in this study. Gastric cancer specimens were evaluated for the gene expression of CTAs, Kitakyushu lung cancer antigen-1 (KK-LC-1), melanoma antigen (MAGE)-A1, MAGE-A3 and New York esophageal cancer-1 (NY-ESO-1), by reverse transcription PCR. Clinicopathological background information, such as gender, age, tumor size, macroscopic type, tumor histology, depth of invasion, lymph node metastasis, lymphatic invasion, venous invasion, and pathological stage, was obtained. Statistical comparisons between the expression of each CTA and each clinicopathological background were performed using the χ² test.

RESULTS

The expression rates of KK-LC-1, MAGE-A1, MAGE-A3, and NY-ESO-1 were 79.5%, 32.5%, 39.8%, and 15.7%, respectively. In early stage gastric cancer specimens, the expression of KK-LC-1 was 79.4%, which is comparable to the 79.6% observed in advanced stage specimens. The expression of KK-LC-1 was not significantly associated with clinicopathological factors, while there were considerable differences in the expression rates of MAGE-A1 and MAGE-A3 with vs without lymphatic invasion (MAGE-A1, 39.3% vs 13.6%, P = 0.034; MAGE-A3, 47.5% vs 18.2%, P = 0.022) and/or vascular invasion (MAGE-A1, 41.5% vs 16.7%, P = 0.028; MAGE-A3, 49.1% vs 23.3%, P = 0.035) and, particularly, MAGE-A3, in patients with early vs advanced stage (36.5% vs 49.0%, P = 0.044), respectively. Patients expressing MAGE-A3 and NY-ESO-1 were older than those not expressing MAGE-A3 and NY-ESO-1 (MAGE-A3, 73.7 ± 7.1 vs 67.4 ± 12.3, P = 0.009; NY-ESO-1, 75.5 ± 7.2 vs 68.8 ± 11.2, P = 0.042).

CONCLUSION

The KK-LC-1 expression rate was high even in patients with stage I cancer, suggesting that KK-LC-1 is a useful biomarker for early diagnosis of gastric cancer.

NY-ESO-1 expression predicts an aggressive phenotype of ovarian cancer

OBJECTIVES

NY-ESO-1 is a cancer testis antigen and a promising target for immunotherapy. The purpose of this study was to determine the expression frequency, immunogenicity, and clinical impact of NY-ESO-1 in ovarian cancer.

METHODS

Immunohistochemistry (IHC), reverse-transcription polymerase chain reaction (RT-PCR), and quantitative-PCR (qRT-PCR) were utilized in an ovarian cancer (including Fallopian tube and primary peritoneal cancers) patient cohort; humoral responses against NY-ESO-1 were determined by ELISA. Clinicopathologic outcomes including progression-free (PFS) and overall (OS) survival were evaluated based on NY-ESO-1 expression. Cohen's kappa (κ) tested agreement between expression tests.

RESULTS

NY-ESO-1 expression was detected by any method in 40.7% of 1002 patients' tumors (NY-ESO-1+) and baseline humoral response was identified in 19.0% of 689 tested patients. NY-ESO-1+ patients were older (p<0.001), higher stage (85% stage III/IV vs. 76.4%, p=0.015), less likely to have a complete response to initial therapy (53.9% vs. 68.9%, p=0.002), had more serous histotype (74.5% vs. 66.9%, p=0.011), and had more grade 3 tumors (83.7% vs. 70.8%, p<0.001). There was a trend towards shorter PFS (22.2 vs. 25.0months, p=0.07) and significantly shorter OS (42.9 vs. 50.0months, p=0.003) among NY-ESO-1+ patients. A subset analysis of NY-ESO-1+ patients that received immunotherapy demonstrated improved OS by >2years (52.6 vs. 27.2months, p<0.001).

CONCLUSIONS

This study is the first demonstration of an association between NY-ESO-1 expression and an aggressive cancer phenotype. The relatively high expression frequency of NY-ESO-1 in ovarian cancer patients coupled with the poor clinical outcomes in NY-ESO-1+ patients reveals an underappreciated need for targeted therapy against this antigen. In support, our study reveals that NY-ESO-1+ patients enrolled on immunotherapy trials targeting the antigen exhibited an improvement in OS.

Melanoma: tumor microenvironment and new treatments

In the recent past years, many discoveries in the tumor microenvironment have led to changes in the management of melanoma and it is rising up hopes, specially, to those in advanced stages. FDA approved seven new drugs from 2011 to 2014. They are: Vemurafenib, Dabrafenib and Trametinib, kinases inhibitors used for patients that have BRAFV600E mutation; Ipilimumab (anti-CTLA4), Pembrolizumab (anti-PD-1) and Nivolumab (anti-PD-1), monoclonal antibodies that stimulate the immune system; and Peginterferon alfa-2b, an anti-proliferative cytokine used as adjuvant therapy. In this article, we will review the molecular bases for these new metastatic melanoma therapeutic agents cited above and also analyze new molecular discoveries in melanoma study, as Cancer-Testis antigens (CT). They are capable of induce humoral and cellular immune responses in cancer patients and because of this immunogenicity and their restrict expression in normal tissues, they are considered an ideal candidate for vaccine development against cancer. Among CT antigens, NY-ESO-1 is the best characterized in terms of expression patterns and immunogenicity. It is expressed in 20-40% of all melanomas, more in metastatic lesions than in primary ones, and it is very heterogeneous inter and intratumoral. Breslow index is associate with NY-ESO-1 expression in primary cutaneous melanomas, but its relation to patient survival remains controversial.

Immunotherapy for Gastroesophageal Cancer

Survival for patients with advanced oesophageal and stomach cancer is poor; together these cancers are responsible for more than a million deaths per year globally. As chemotherapy and targeted therapies such as trastuzumab and ramucirumab result in modest improvements in survival but not long-term cure for such patients, development of alternative treatment approaches is warranted. Novel immunotherapy drugs such as checkpoint inhibitors have been paradigm changing in melanoma, non-small cell lung cancer and urothelial cancers. In this review, we assess the early evidence for efficacy of immunotherapy in patients with gastroesophageal cancer in addition to considering biomarkers associated with response to these treatments. Early results of Anti- Programmed Cell Death Protein-1 (anti-PD-1), anti-PD-L1 and anti-Cytotoxic T-lymphocyte assosciated protein-4 (anti-CTLA4) trials are examined, and we conclude with a discussion on the future direction for immunotherapy for gastroesophageal cancer patients.

Expression of MAGE-A and NY-ESO-1 in Primary and Metastatic Cancers

Melanoma-associated antigen-A (MAGE-A) and New York esophageal squamous cell cancer-1 (NY-ESO-1) are 2 cancer testis antigens (CTA) demonstrating potential for use in targeted immunotherapy. Clinical trials in melanoma and synovial sarcomas targeting these antigens in immune-based therapies have demonstrated durable tumor regression. Although protein expression of NY-ESO-1 has been assessed in a variety of cancer types, the expression of MAGE-A has not been studied in depth. In this study we analyzed MAGE-A and NY-ESO-1 expression in 314 melanoma specimens from 301 melanoma patients, 38 patients with squamous cell cancers and 111 patients with adenocarcinomas. Our results demonstrated higher expression of MAGE-A compared with NY-ESO-1 in melanomas (32% vs. 13%) and squamous cell carcinomas (45% vs. 7.9%), and higher expression of both CTAs in metastatic versus primary tumors. CTA expression in adenocarcinomas was low (MAGE-A: 10%, NY-ESO-1: 0.9%). In addition, we looked at concordance of expression among metastatic melanoma lesions within the same patient and found concordant expression in 38 of 47 patients for MAGE-A and 43 of 47 patients for NY-ESO-1. Our study demonstrated that the MAGE-A family may be of greater utility than NY-ESO-1 for targeted immunotherapy in a variety of cancer histologies, in particular metastatic melanomas and squamous cell carcinomas.

Expression of Cancer Testis Antigens in Colorectal Cancer: New Prognostic and Therapeutic Implications

Background. While cancer/testis antigens (CTAs) are restricted in postnatal tissues to testes and germ line-derived cells, their role in cancer development and the clinical significance of their expression still remain to be better defined. Objective. The aim of this study was to investigate the level of CTA expression in colon samples from patients with colorectal cancer (CRC) in relation to patient clinical status. Methods. Forty-five patients with newly diagnosed colorectal cancer were included in the study. We selected a panel of 18 CTAs that were previously detected in CRC as well as some new gene candidates, and their expression was detected at the mRNA level by employing RQ-PCR. Additionally, we evaluated CTA expression in three colon cancer cell lines (CL-188, HTB-39, and HTB-37) after exposure to the DNA methylation-modifying drug 5-azacytidine. Results. We report that 6 out of 18 (33%) CTAs tested (MAGEA3, OIP5, TTK, PLU1, DKKL1, and FBXO39) were significantly (p < 0.05) overexpressed in tumor tissue compared with healthy colon samples isolated from the same patients. Conclusions. Moreover, we found that MAGEA3, PLU-1, and DKKL expression positively correlated with disease progression, evaluated according to the Dukes staging system. Finally, 5-azacytidine exposure significantly upregulated expression of CTAs on CRC cells, which indicates that this demethylation agent could be employed therapeutically to enhance the immune response against tumor cells.

Evaluation of MAGE-1 Cancer-Testis Antigen Expression in Invasive Breast Cancer and its Correlation with Prognostic Factors

Background

Aberrant expression of cancer-testis antigens (CTA) in breast carcinoma tissue, and its natural expression in the testis, the tissue away from the immune system, makes them good candidates for cancer immunotherapy and vaccines designing.

Objectives

The aim of this study was to assess the expression of a CTA (MAGE-1) in invasive breast cancer and its correlation with prognostic factors.

Methods

Paraffin blocks of breast cancer tissues from 113 patients operated in 2011 - 2013 were stained for MAGE-1expression by immunohistochemistry (IHC). The associations of MAGE-1 expression with known prognostic factors were assessed by statistical analysis using SPSS 16.

Results

MAGE-1 expression was found in cancer cell cytoplasms of 30.1% of patients, with different degrees of intensity, (23.9% moderate and 6.2% strong). Nuclear staining turned positive in 31.8%, stratified from moderate in 26.5%to to strong in 5.3%. There was a significant association between the number of lymph nodes involved and both nuclear (P = 0.042) and cytoplasmic (P = 0.003) MAGE-1 expression. There was also a significant correlation between the nuclear expression of MAGE-1 and tumor size (P = 0.018). Cytoplasmic expression of MAGE-1 increased with increasing pathologic grade of tumors although the association was not statistically significant (P = 0.119).

Conclusions

CTA MAGE-1 has significant association with some prognostic factors in breast cancer and may have the role of a prognostic factor.

Dendritic cell-based cancer immunotherapy for colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers and a leading cause of cancer-related mortality worldwide. Although systemic therapy is the standard care for patients with recurrent or metastatic CRC, the prognosis is extremely poor. The optimal sequence of therapy remains unknown. Therefore, alternative strategies, such as immunotherapy, are needed for patients with advanced CRC. This review summarizes evidence from dendritic cell-based cancer immunotherapy strategies that are currently in clinical trials. In addition, we discuss the possibility of antitumor immune responses through immunoinhibitory PD-1/PD-L1 pathway blockade in CRC patients.

Consequences of point mutations in melanoma-associated antigen 4 (MAGE-A4) protein: Insights from structural and biophysical studies

The Melanoma-Associated Antigen A4 (MAGE-A4) protein is a target for cancer therapy. The function of this protein is not well understood. We report the first comprehensive study on key cancer-associated MAGE-A4 mutations and provide analysis on the consequences of these mutations on the structure, folding and stability of the protein. Based on Nuclear Magnetic Resonance and Circular Dichroism, these mutations had no significant effects on the structure and the folding of the protein. Some mutations affected the thermal stability of the protein remarkably. Native mass spectrometry of wild-type MAGE-A4 showed a broad charge state distribution suggestive of a structurally dynamic protein. Significant intensity was found in relatively low charge states, indicative of a predominantly globular form and some population in more extended states. The latter is supported by Ion Mobility measurements. The MAGE-A4 mutants exhibited similar features. These novel molecular insights shed further light on better understanding of these proteins, which are implicated in a wide range of human cancers.

NY-ESO-1 autoantibody as a tumor-specific biomarker for esophageal cancer: screening in 1969 patients with various cancers

BACKGROUND

Although serum NY-ESO-1 antibodies (s-NY-ESO-1-Abs) have been reported in patients with esophageal carcinoma, this assay system has not been used to study a large series of patients with various other cancers.

PATIENTS AND METHODS

Serum samples of 1969 cancer patients [esophageal cancer (n = 172), lung cancer (n = 269), hepatocellular carcinoma (n = 91), prostate cancer (n = 358), gastric cancer (n = 313), colorectal cancer (n = 262), breast cancer (n = 365)] and 74 healthy individuals were analyzed using an originally developed enzyme-linked immunosorbent assay system for s-NY-ESO-1-Abs. The optical density cut-off value, determined as the mean plus three standard deviations for serum samples from the healthy controls, was fixed at 0.165. Conventional tumor markers were also evaluated in patients with esophageal carcinoma.

RESULTS

The positive rate of s-NY-ESO-1-Abs in patients with esophageal cancer (31 %) was significantly higher than that in the other groups: patients with lung cancer (13 %), patients with hepatocellular carcinoma (11 %), patients with prostate cancer (10 %), patients with gastric cancer (10 %), patients with colorectal cancer (8 %), patients with breast cancer (7 %), and healthy controls (0 %). The positive rate of s-NY-ESO-1-Abs was comparable to that of serum p53 antibodies (33 %), squamous cell carcinoma antigen (36 %), carcinoembryonic antigen (26 %), and CYFRA 21-1 (18 %) and gradually increased with the tumor stage.

CONCLUSIONS

The positive rate of s-NY-ESO-1-Abs was significantly higher in patients with esophageal cancer than in patients with the other types of cancers. On the basis of its high specificity and sensitivity, even in patients with stage I tumors, s-NY-ESO-1-Abs may be one of the first choices for esophageal cancer.

Cancer-testis genes as candidates for immunotherapy in breast cancer

Cancer-testis (CT) antigens are tumor-associated antigens attracting immunologists for their possible application in the immunotherapy of cancer. Several clinical trials have assessed their therapeutic potentials in cancer patients. Breast cancers, especially triple-negative cancers are among those with significant expression of CT genes. Identification of CT genes with high expression in cancer patients is the prerequisite for any immunotherapeutic approach. CT genes have gained attention not only for immunotherapy of cancer patients, but also for immunoprevention in high-risk individuals. Many CT genes have proved to be immunogenic in breast cancer patients suggesting the basis for the development of polyvalent vaccines.

T cell-based targeted immunotherapies for patients with multiple myeloma

Despite high-dose chemotherapy followed by autologs stem-cell transplantation as well as novel therapeutic agents, multiple myeloma (MM) remains incurable. Following the general trend towards personalized therapy, targeted immunotherapy as a new approach in the therapy of MM has emerged. Better progression-free survival and overall survival after tandem autologs/allogeneic stem cell transplantation suggest a graft versus myeloma effect strongly supporting the usefulness of immunological therapies for MM patients. How to induce a powerful antimyeloma effect is the key issue in this field. Pivotal is the definition of appropriate tumor antigen targets and effective methods for expansion of T cells with clinical activity. Besides a comprehensive list of tumor antigens for T cell-based approaches, eight promising antigens, CS1, Dickkopf-1, HM1.24, Human telomerase reverse transcriptase, MAGE-A3, New York Esophageal-1, Receptor of hyaluronic acid mediated motility and Wilms' tumor gene 1, are described in detail to provide a background for potential clinical use. Results from both closed and on-going clinical trials are summarized in this review. On the basis of the preclinical and clinical data, we elaborate on three encouraging therapeutic options, vaccine-enhanced donor lymphocyte infusion, chimeric antigen receptors-transfected T cells as well as vaccines with multiple antigen peptides, to pave the way towards clinically significant immune responses against MM.

Epigenetic mechanisms underlying the dynamic expression of cancer-testis genes, PAGE2, -2B and SPANX-B, during mesenchymal-to-epithelial transition

Cancer-testis (CT) genes are expressed in various cancers but not in normal tissues other than in cells of the germline. Although DNA demethylation of promoter-proximal CpGs of CT genes is linked to their expression in cancer, the mechanisms leading to demethylation are unknown. To elucidate such mechanisms we chose to study the Caco-2 colorectal cancer cell line during the course of its spontaneous differentiation in vitro, as we found CT genes, in particular PAGE2, -2B and SPANX-B, to be up-regulated during this process. Differentiation of these cells resulted in a mesenchymal-to-epithelial transition (MET) as evidenced by the gain of epithelial markers CDX2, Claudin-4 and E-cadherin, and a concomitant loss of mesenchymal markers Vimentin, Fibronectin-1 and Transgelin. PAGE2 and SPAN-X up-regulation was accompanied by an increase in Ten-eleven translocation-2 (TET2) expression and cytosine 5-hydroxymethylation as well as the disassociation of heterochromatin protein 1 and the polycomb repressive complex 2 protein EZH2 from promoter-proximal regions of these genes. Reversal of differentiation resulted in down-regulation of PAGE2, -2B and SPANX-B, and induction of epithelial-to-mesenchymal transition (EMT) markers, demonstrating the dynamic nature of CT gene regulation in this model.

Inhibition of human esophageal squamous cell carcinomas by targeted silencing of tumor enhancer genes: an overview

Esophageal cancer has been reported as the ninth most common malignancy and ranks as the sixth most frequent cause of death worldwide. Esophageal cancer treatment involves surgery, chemotherapy, radiation therapy, or combination therapy. Novel strategies are needed to boost the oncologic outcome. Recent advances in the molecular biology of esophageal cancer have documented the role of genetic alterations in tumorigenesis. Oncogenes serve a pivotal function in tumorigenesis. Targeted therapies are directed at the unique molecular signature of cancer cells for enhanced efficacy with low toxicity. RNA interference (RNAi) technology is a powerful tool for silencing endogenous or exogenous genes in mammalian cells. Related results have shown that targeting oncogenes with siRNAs, specifically the mRNA, effectively reduces tumor cell proliferation and induces apoptotic cell death. This article will briefly review studies on silencing tumor enhancer genes related to the induction of esophageal cancer.

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.

Expressions of MAGE-A9 and MAGE-A11 in breast cancer and their expression mechanism

BACKGROUND AND AIMS

The MAGE gene encodes cancer/testis antigens that are selectively expressed in various types of human neoplasms but not in normal tissues other than testis and placenta. However, the expression pattern of MAGE-A9 and MAGE-A11 in breast cancer patients is still unclear. The purpose of our study is to investigate the expression pattern and mechanism of MAGE-A9 and MAGE-A11 in breast cancer patients.

METHODS

The expression of MAGE-A9 and MAGE-A11 was investigated in 60 breast benign diseases specimens, 60 tumor-free breast specimens and 60 breast cancer specimens by RT-PCR, and their correlation with clinicopathological parameters was elucidated. We examined the influence of the DNA methylase inhibitor 5-aza-2'-deoxycytidine (5-aza-CdR) together with the histone deacetylase inhibitor trichostatin A (TSA) on the expression of MAGE-A9 and MAGE-A11 genes in two breast cancer cell lines.

RESULTS

The expression rates of MAGE-A9 and MAGE-A11 in breast cancer specimens were 45 and 66.7%, respectively. MAGE-A9 and MAGE-A11 expression was positively associated with estrogen-receptor (ER) and HER-2 expression (p <0.05). 5-Aza-CdR treatment alone could induce the expression of MAGE-A9 and MAGE-A11 in cell lines that did not express this antigen. TSA treatment alone had no influence on MAGE-A9 and MAGE-A11 gene expression. However, TSA was able synergistically to enhance 5-aza-CdR-mediated MAGE-A transcription (p <0.05).

CONCLUSIONS

Our data show that MAGE-A9 and MAGE-A11 are tumor-specific antigens and not only DNA hypermethylation but also histone deacetylation is responsible for the mechanism underlying MAGE-A9 and MAGE-A11 gene silencing.

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.

NY-ESO-1 expression in synovial sarcoma and other mesenchymal tumors: significance for NY-ESO-1-based targeted therapy and differential diagnosis

A promising targeted therapy against NY-ESO-1 (CTAG 1B) using genetically modified T-cells in synovial sarcomas was recently demonstrated in a clinical trial at the NCI. To investigate the role of NY-ESO-1 immunohistochemistry in patient selection and gain better insight into the incidence of NY-ESO-1 expression in synovial sarcomas and other mesenchymal tumors, we evaluated NY-ESO-1 expression by immunohistochemistry in 417 tumors. This collection of samples included: 50 SS18/SSX1/2 fusion positive synovial sarcomas, 155 gastrointestinal stromal tumors (GIST), 135 other spindle cell sarcomas as well as 77 other sarcomas (chondrosarcoma, osteosarcoma, dedifferentiated liposarcoma, alveolar soft part sarcoma, rhabdomyosarcoma, angiosarcoma, malignant mesothelioma, and Ewing's sarcoma). We report that 76% of synovial sarcomas expressed NY-ESO-1 in a strong and diffuse pattern (2-3+, >50-70% of tumor cells). In contrast, only rare cases of other spindle cell mesenchymal tumor expressed NY-ESO-1 (GIST (2/155), malignant peripheral nerve sheath tumors (1/34), and dermatofibrosarcoma protuberans (2/20)). Individual cases of other sarcomas (angiosarcoma, malignant mesothelioma, chondrosarcoma, osteosarcoma, dedifferentiated liposarcoma, alveolar soft part sarcoma, and Ewing's sarcoma) were positive for NY-ESO-1. However, no positive cases were identified amongst our cohort of leiomyosarcomas (0/24), hemangiopericytoma/solitary fibrous tumors (0/40), and cellular schwannomas (0/17). In summary, we find that NY-ESO-1 is strongly and diffusely expressed in a majority of synovial sarcomas, but only rarely in other mesenchymal lesions. Beyond its role in patient selection for targeted therapy, immunohistochemistry for NY-ESO-1 may be diagnostically useful for the distinction of synovial sarcoma from other spindle cell neoplasms.

Integrated, genome-wide screening for hypomethylated oncogenes in salivary gland adenoid cystic carcinoma

PURPOSE

Salivary gland adenoid cystic carcinoma (ACC) is a rare malignancy that is poorly understood. To look for relevant oncogene candidates under the control of promoter methylation, an integrated, genome-wide screen was conducted.

EXPERIMENTAL DESIGN

Global demethylation of normal salivary gland cell strains using 5-aza-2'-deoxycytidine (5-aza-dC) and trichostatin A (TSA), followed by expression array analysis was conducted. ACC-specific expression profiling was generated using expression microarray analysis of primary ACC and normal samples. Next, the two profiles were integrated to identify a subset of genes for further validation of promoter demethylation in ACC versus normal. Finally, promising candidates were further validated for mRNA, protein, and promoter methylation levels in larger ACC cohorts. Functional validation was then conducted in cancer cell lines.

RESULTS

We found 159 genes that were significantly re-expressed after 5-aza-dC/TSA treatment and overexpressed in ACC. After initial validation, eight candidates showed hypomethylation in ACC: AQP1, CECR1, C1QR1, CTAG2, P53AIP1, TDRD12, BEX1, and DYNLT3. Aquaporin 1 (AQP1) showed the most significant hypomethylation and was further validated. AQP1 hypomethylation in ACC was confirmed with two independent cohorts. Of note, there was significant overexpression of AQP1 in both mRNA and protein in the paraffin-embedded ACC cohort. Furthermore, AQP1 was upregulated in 5-aza-dC/TSA-treated SACC83. Finally, AQP1 promoted cell proliferation and colony formation in SACC83.

CONCLUSIONS

Our integrated, genome-wide screening method proved to be an effective strategy for detecting novel oncogenes in ACC. AQP1 is a promising oncogene candidate for ACC and is transcriptionally regulated by promoter hypomethylation.

MAGE-A3/4 and NY-ESO-1 antigens expression in metastatic esophageal squamous cell carcinoma

In the present study we analyzed immunohistochemical expression of MAGE-A 3/4 and NY-ESO-1 in 55 samples of esophageal squamous cell carcinomas (ESCC) and their respective lymph node metastases. To our knowledge this is the first study to assess and compare the expression of these antigens in ESCC lymph node metastases.

Fifty (90.9%) primary ESCC were positive for MAGE-A 3/4 and 53 (96.6%) were positive for NY-ESO-1. MAGE-A 3/4 was expressed in all lymph node metastases and the intensity of expression was high in a majority of cases. NY-ESO-1 was negative in 2 (7.1%) lymph nodes metastases, while the reaction was predominantly moderate in the positive group. In primary tumors MAGE-A 3/4 showed a significantly higher intensity of expression compared to NY-ESO-1 (P=0.047), while in lymph node metastases the intensity of expression was not significantly different (P=0.387). Primary tumors with and without lymph node metastases showed no significant differences in MAGE-A 3/4 (P=0.672) and NY-ESO-1 (P=0.444) expression. Intensity of MAGE-A 3/4 (P=0.461) and NY-ESO-1 (P=0.414) expression in primary tumors was not significantly different compared to the expression in their respective lymph nodes metastases. Expression of MAGE-A 3/4 in primary tumors showed significant positive correlation with primary tumor expression of NY-ESO-1 (P=0.021) but no significant correlation with the expression of MAGE-A 3/4 in lymph node metastases (P=0.056). Expression of NY-ESO-1 in primary tumors showed significant positive correlation with the expression of NY-ESO-1 in lymph node metastases (P=0.001) and significant negative correlation with patients' age (P<0.001). Expression of MAGE-A 3/4 and NY-ESO-1 in primary tumors and lymph node metastases showed no significant correlation with prognostic parameters such as tumor grade and TNM stage (P>0.05). We have shown different levels of MAGE-A 3/4 and NY-ESO-1 expression in almost all specimens of primary tumor and lymph node metastases, suggesting that ESCC may be possible target of immunotherapy and anti-tumor vaccination. High levels of expression in lymph node metastases indicate possible clinical benefit of postoperative vaccine with MAGE-A3 and NY-ESO-1 in advanced stage of disease.

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.

The SSX family of cancer-testis antigens as target proteins for tumor therapy

Cancer-testis antigens (CTAs) represent an expanding class of tumor-associated proteins defined on the basis of their tissue-restricted expression to testis or ovary germline cells and frequent ectopic expression in tumor tissue. The expression of CTA in MHC class I-deficient germline cells makes these proteins particularly attractive as immunotherapeutic targets because they serve as essentially tumor-specific antigens for MHC class I-restricted CD8+ T cells. Moreover, because CTAs are expressed in many types of cancer, any therapeutic developed to target these antigens might have efficacy for multiple cancer types. Of particular interest among CTAs is the synovial sarcoma X chromosome breakpoint (SSX) family of proteins, which includes ten highly homologous family members. Expression of SSX proteins in tumor tissues has been associated with advanced stages of disease and worse patient prognosis. Additionally, both humoral and cell-mediated immune responses to SSX proteins have been demonstrated in patients with tumors of varying histological origin, which indicates that natural immune responses can be spontaneously generated to these antigens in cancer patients. The current review will describe the history and identification of this family of proteins, as well as what is known of their function, expression in normal and malignant tissues, and immunogenicity.

NY-CO-58/KIF2C is overexpressed in a variety of solid tumors and induces frequent T cell responses in patients with colorectal cancer

NY-CO-58/KIF2C has been identified as a tumor antigen by screening antibody responses in patients with colorectal cancer. However, expression had not consequently been examined, and nothing was known about its ability to induce spontaneous T cell responses, which have been suggested to play a role in the development of colorectal cancer. We analyzed 5 colorectal cancer cell lines, and tumor samples and adjacent healthy tissues from 176 patients with epithelial cancers for the expression of NY-CO-58/KIF2C by RT-PCR and Western Blot. T cell responses of 43 colorectal cancer patients and 35 healthy donors were evaluated by ELISpot following stimulation with 30mer peptides or full-length protein. All cell lines and tumor samples from colorectal cancer patients expressed NY-CO-58/KIF2C on the protein and RNA level, and expression levels correlated strongly with Ki-67 expression (r = 0.69; p = 0.0003). Investigating NY-CO-58/KIF2C-specific T cell responses, CD8(+) T cells directed against 1 or more peptides were found in less than 10% of patients, whereas specific CD4(+) T cells were detected in close to 50% of patients. These T cells were of high avidity, recognized the naturally processed antigen and secreted IFN-gamma and TNF-alpha. Depletion of CD4(+)CD25(+) T cells before stimulation significantly increased the intensity of the preexisting response. NY-CO-58/KIF2C is significantly overexpressed in colorectal and other epithelial cancers and expression levels correlate with the proliferative activity of the tumor. Importantly, NY-CO-58/KIF2C was able to induce spontaneous CD4(+) T cell responses of the Th1-type, which were tightly controlled by peripheral T regulatory cells.

Sperm protein 17 is a novel marker for predicting cisplatin response in esophageal squamous cancer cell lines

Expression of sperm protein 17 (Sp17) mRNA has been reported in various malignancies. In an earlier study, we reported the upregulation of Sp17 transcripts in primary esophageal squamous cell carcinomas (ESCCs) using differential display and detected Sp17 transcripts in 86% of ESCCs by RT-PCR, whereas no transcripts were detected in the paired normal esophageal tissues. Herein we hypothesized that Sp17 might be used as a marker for detecting the response of anticancer therapies in ESCCs. Our results indicated that Sp17 protein levels in esophageal squamous cancer cell lines decreased in response to treatment with (i) the HSP90 activity inhibitor geldanamycin, (ii) the tyrosine kinase inhibitor erlotinib and (iii) cisplatin (chemotherapeutic agent commonly used in management of ESCC). In contrast, the Sp17 levels did not decrease in response to radiation therapy and treatment with the chemotherapeutic agent, gemcitabine. Further investigations showed that cisplatin induced decrease in Sp17 levels was due to transcriptional inhibition and cisplatin-resistant cell lines did not show this decrease in Sp17 levels in response to cisplatin treatment. In addition, we also carried our mass spectophotometric analysis to identify the binding partners of Sp17 to characterize its possible involvement in esophageal tumorigenesis and chemoresistance.

mRNA expression of the XAGE-1 gene in human acute leukemia

XAGE-1 is a cancer-testis antigen, which was demonstrated to be expressed at a significant frequency and to be immunogenic in some solid tumors. We analyzed the expression of 4 XAGE-1 transcript variant gene in human acute leukemias by reverse-transcription polymerase chain reaction. Among the 114 acute leukemias, 14/63 (22.22%) of the acute myeloid leukemia samples were positive for XAGE-1b genes. XAGE-1b mRNA expression was detected in 10/51 (19.61%) of the acute lymphocyte leukemia samples. However, we did not find any important correlation between XAGE-1b mRNA expression and clinical characteristics, such as sex, leukemia type, response to therapy and the percentage of blast in the first diagnosed bone marrow. We concluded that the XAGE-1b gene was expressed at the mRNA level in a proportion of human acute leukemia.

Antibody responses against NY-ESO-1 and HER2 antigens in patients vaccinated with combinations of cholesteryl pullulan (CHP)-NY-ESO-1 and CHP-HER2 with OK-432

Combination vaccines of the NY-ESO-1 protein complexed with cholesteryl pullulan (CHP), CHP-NY-ESO-1, and the truncated 146HER2 protein with CHP, CHP-HER2, were subcutaneously administered with the immuno-adjuvant OK-432 to eight esophageal cancer patients. Vaccination was well-tolerated. NY-ESO-1- and HER2-specific antibody responses were analyzed using the patients' sera and samples from previous single CHP-NY-ESO-1 or CHP-HER2 vaccine trial. The responses to NY-ESO-1 in the combination vaccine study were comparable to the single vaccine. For responses to HER2, there were fewer antibody responses in the combination vaccines. Although there were marked individual variations in the antibody responses to the NY-ESO-1 and HER2 antigens, the reaction patterns to these antigens were comparable within each patient. Antibodies to OK-432 were not augmented. Protein cancer vaccines targeting multiple antigens are feasible.

Infrequent and low expression of cancer-testis antigens located on the X chromosome in colorectal cancer: implications for immunotherapy in South African populations

Cancer-testis (CT) antigens are a group of tumor antigens that are expressed in the testis and aberrantly in cancerous tissue but not in somatic tissues. The testis is an immune-privileged site because of the presence of a blood-testis barrier; as a result, CT antigens are considered to be essentially tumor specific and are attractive targets for immunotherapy. CT antigens are classified as the CT-X and the non-X CT antigens depending on the chromosomal location to which the genes are mapped. CT-X antigens are typically highly immunogenic and hence the first step towards tailored immunotherapy is to elucidate the expression profile of CT-X antigens in the respective tumors. In this study we investigated the expression profile of 16 CT-X antigen genes in 34 colorectal cancer (CRC) patients using reverse transcription-polymerase chain reaction. We observed that 12 of the 16 CT-X antigen genes studied did not show expression in any of the CRC samples analyzed. The other 4 CT-X antigen genes showed low frequency of expression and exhibited a highly variable expression profile when compared to other populations. Thus, our study forms the first report on the expression profile of CT-X antigen genes among CRC patients in the genetically diverse South African population. The results of our study suggest that genetic and ethnic variations in population might have a role in the expression of the CT-X antigen genes. Thus our results have significant implications for anti-CT antigen-based immunotherapy trials in this population.