Cancer-testis antigens: promising targets for antigen directed antineoplastic immunotherapy

NanoString technology distinguishes anti-TIF-1γ+ from anti-Mi-2+ dermatomyositis patients

Dermatomyositis (DM) is a systemic idiopathic inflammatory disease affecting skeletal muscle and skin, clinically characterized by symmetrical proximal muscle weakness and typical skin lesions. Recently, myositis-specific autoantibodies (MSA) became of utmost importance because they strongly correlate with distinct clinical manifestations and prognosis. Antibodies against transcription intermediary factor 1γ (TIF-1γ) are frequently associated with increased risk of malignancy, a specific cutaneous phenotype and limited response to therapy in adult DM patients. Anti-Mi-2 autoantibodies, in contrast, are typically associated with classic DM rashes, prominent skeletal muscle weakness, better therapeutic response and prognosis, and less frequently with cancer. Nevertheless, the sensitivity of autoantibody testing is only moderate, and alternative reliable methods for DM patient stratification and prediction of cancer risk are needed. To further investigate these clinically distinct DM subgroups, we herein analyzed 30 DM patients (n = 15 Mi-2⁺ and n = 15 TIF-1 γ⁺ ) and n = 8 non-disease controls (NDC). We demonstrate that the NanoString technology can be used as a very sensitive method to clearly differentiate these two clinically distinct DM subgroups. Using the nCounter PanCancer Immune Profiling Panel™, we identified a set of significantly dysregulated genes in anti-TIF-1γ⁺ patient muscle biopsies including VEGFA, DDX58, IFNB1, CCL5, IL12RB2, and CD84. Investigation of type I IFN-regulated transcripts revealed a striking type I interferon signature in anti-Mi-2⁺ patient biopsies. Our results help to stratify both subgroups and predict, which DM patients require an intensified diagnostic procedure and might have a poorer outcome. Potentially, this could also have implications for the therapeutic approach.

Cutaneous Malignant Melanoma: A Review of Early Diagnosis and Management

Cutaneous melanoma (CM) is a malignant tumor formed from pigment-producing cells called melanocytes. It is one of the most aggressive and fatal forms of skin malignancy. In the last decades, CM's incidence has gradually risen, with 351,880 new cases in 2015. Since the 1960s, its incidence has increased steadily, in 2019, with approximately 96,000 new cases. A greater understanding of early diagnosis and management of CM is urgently needed because of the high mortality rates due to metastatic melanoma. Timely detection of melanoma is crucial for successful treatment, but diagnosis with histopathology may also pose a significant challenge to this objective. Early diagnosis and management are essential and contribute to better survival rates of the patient. To better control this malignancy, such information is expected to be particularly useful in the early detection of possible metastatic lesions and the development of new therapeutic approaches. This article reviews the available information on the early diagnosis and management of CM and discusses such information's potential in facilitating the future prospective.

C/EBPβ promotes the viability of human bladder cancer cell by contributing to the transcription of bladder cancer specific lncRNA UCA1

Urothelial Carcinoma Antigen 1 (UCA1) is a cell and tissue specific long non-coding RNA (lncRNA) associated with the tumorigenesis and invasion of bladder cancer. However, the mechanism driving the over-transcription of UCA1 in bladder cancer cells remains unclear. It has been reported that C/EBPβ has a significant role of regulation in tumorigenesis. Here we report that the expression of UCA1 was dramatically inhibited in 5637 cells with C/EBPβ down-regulation. Additionally, the function tests indicated that C/EBPβ could promote 5637 cells growth and colony formation by inducing the expression level of UCA1. These data suggest that C/EBPβ was involved in transcriptional regulation of UCA1 and contributed substantially to its high expression and proliferation promoting in bladder cancer cells.

Expression of cancer/testis antigens MAGE-A, MAGE-C1, GAGE and CTAG1B in benign and malignant thyroid diseases

Despite considerable advances in the understanding of thyroid gland biology, correctly diagnosing thyroid nodules and treating high-grade thyroid carcinoma remains challenging. Cancer/testis (CT) antigens have emerged as potential diagnostic tools as well as targets of potential cancer vaccinations. In the present study, a total of 117 patients who underwent surgical therapy for thyroid disease were available for analysis. The expression levels of melanoma-associated antigen (MAGE) A, MAGE-C1/CT7, cancer/testis antigen 1B (CTAG1B) and G antigen (GAGE) were analyzed by immunohistochemistry. None of the CT antigens were expressed in the normal thyroid or goiter. In papillary and follicular carcinoma, MAGE-A was present in 8.1% of cases, GAGE in 10.8% and CT/7MAGE-C1 and CTAG1B in 2.7% each. In medullary carcinoma, CT antigen expression was as follows: MAGE-A in 42.9% of patients; MAGE-C1/CT7 in 46.5%; GAGE in 92.9%; and CTAG1B in 3.6%. A statistically significant association was observed between the expression of G MAGE-C1/CT7 and patient gender as well as patient clinical stage (P=0.029 and 0.031, respectively). In poorly differentiated and anaplastic carcinoma cases, CT antigen expression was as follows: MAGE-A in 61.8% of cases; MAGE-C1 in 57.1%; GAGE in 66.7%; and CTAG1B in 14.4%. There was a statistically significant association between expression of GAGE and gender (P=0.043). However, there was no association between CT antigen expression and patient survival in any of the tumor entities analyzed. The current study identified a distinct expression pattern of CT antigens in malignant thyroid tumors indicating that CT antigens have the potential to outperform existing thyroid cancer biomarkers. The prevalence of CT antigens in high-grade carcinomas suggests that they serve an important biological role within malignant tumors.

Case report: whole exome sequencing of primary cardiac angiosarcoma highlights potential for targeted therapies

Background

Primary cardiac angiosarcomas are rare, but they are the most aggressive type of primary cardiac neoplasms. When patients do present, it is with advanced pulmonary and/or cardiac symptoms. Therefore, many times the correct diagnosis is not made at the time of initial presentation. These patients have metastatic disease and the vast majority of these patients die within a few months after diagnosis. Currently the treatment choices are limited and there are no targeted therapies available.

Case presentation

A 56-year-old male presented with shortness of breath, night sweats, and productive cough for a month. Workup revealed pericardial effusion and multiple bilateral pulmonary nodules suspicious for metastatic disease. Transthoracic echocardiogram showed a large pericardial effusion and a large mass in the base of the right atrium. Results of biopsy of bilateral lung nodules established a diagnosis of primary cardiac angiosarcoma. Aggressive pulmonary disease caused rapid deterioration; the patient went on hospice and subsequently died. Whole exome sequencing of the patient’s postmortem tumor revealed a novel KDR (G681R) mutation, and focal high-level amplification at chromosome 1q encompassing MDM4, a negative regulator of TP53.

Conclusion

Mutations in KDR have been reported previously in angiosarcomas. Previous studies also demonstrated that KDR mutants with constitutive KDR activation could be inhibited with specific KDR inhibitors in vitro. Thus, patients harboring activating KDR mutations could be candidates for treatment with KDR-specific inhibitors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-3000-z) contains supplementary material, which is available to authorized users.

High expression levels of MAGE-A9 are correlated with unfavorable survival in lung adenocarcinoma

A variety of melanoma-associated antigen-A (MAGE-A) protein are commonly detected in lung cancers. Their biological function is not well characterized but may involve cell cycle progression and the regulation of apoptosis. We hypothesized that MAGE-A9 is involved in the regulation of apoptosis. To test this hypothesis, we evaluated MAGE-A9 protein expression by immunohistochemical staining and we assessed the relationship between the expression of MAGE-A9 and clinical pathological parameters. In addition, we investigated the effect of MAGE-A9 down-regulation in lung adenocarcinoma. The results showed that a high expression level of MAGE-A9 protein in lung adenocarcinoma tumor cells was related to larger tumor diameter (P = 0.013) and poor differentiation (P = 0.029). Cox regression analysis revealed that the expression of MAGE-A9 in lung adenocarcinoma tumor cells (P < 0.001) is an independent prognostic factor in five-year survival rates. NSCLC cells with silenced MAGE-A9 had decreased cell proliferation, migration and invasion in cell culture compared to corresponding control cells. The NSCLC cells showing down-regulated MAGE-A9 induced the expression of apoptosis-associated proteins. In addition, MAGE-A9 was associated with resistance to conventional chemotherapeutic agents. Our findings provide evidence that MAGE-A9 could be a potential therapeutic target in NSCLC.

Programmed death-1 checkpoint blockade in acute myeloid leukemia

INTRODUCTION

Immune checkpoints are regulatory pathways induced in activated T lymphocytes that regulate antigen responsiveness. These immune checkpoints are hijacked by tumors to promote dysfunction of anti-tumor effector cells and consequently of tumor escape from the host immune system.

AREAS COVERED

Programmed death-1/programmed death ligand (PD-1/PDL-1), a checkpoint pathway, has been extensively investigated in leukemia mouse models. Expression of PD-1 on the surface of activated immune cells and of its ligands, PD-L1 and PD-L2, on leukemic blasts has been documented. Clinical trials with PD-1 inhibitors in patients with hematological malignancies are ongoing with promising clinical responses.

EXPERT OPINION

Therapy of hematological cancers with antibodies blocking inhibitory receptors is expected to be highly clinically effective. Checkpoint inhibitory receptors and their ligands are co-expressed on hematopoietic cells found in the leukemic milieu. Several distinct immunological mechanisms are likely to be engaged by antibody-based checkpoint blockade. Co-expression of multiple inhibitory receptors on hematopoietic cells offers an opportunity for combining blocking antibodies to achieve more effective therapy. Up-regulation of receptor/ligand expression in the leukemic milieu may provide a blood marker predictive of response. Finally, chemotherapy-induced up-regulation of PD-1 on T cells after conventional leukemia therapy creates a solid rationale for application of checkpoint blockade as a follow-up therapy.

Decitabine

Besides 5-azacytidine (azacitidine, Vidaza®), 5-aza-2'-deoxycytidine (decitabine, Dacogen®) is the most widely used inhibitor of DNA methylation, which triggers demethylation leading to consecutive reactivation of epigenetically silenced tumor suppressor genes in vitro and in vivo. Although antileukemic activity of decitabine is known for almost 40 years, its therapeutic potential in hematologic malignancies has only recently led to its approval in higher-risk MDS patients and as first-line treatment in AML patients>65 years who are not candidates for intensive chemotherapy. Several clinical trials showed promising activity of low-dose decitabine also in CML and hemoglobinopathies, whereas its efficacy in solid tumors is very limited. Clinical responses appear to be exerted both by epigenetic alterations and by induction of cell-cycle arrest and/or apoptosis. Recent and ongoing clinical trials investigate new dosing schedules, routes of administration, and combination of decitabine with other agents, including histone deacetylase inhibitors.

Potential therapeutic target and independent prognostic marker of TROP2 in laryngeal squamous cell carcinoma

BACKGROUND

The human trophoblastic cell surface antigen 2 (TROP2) gene is associated with the development of malignancies, but its expression in laryngeal squamous cell carcinoma (SCC) and its relationship with clinical characteristics of the disease remain undetermined.

METHODS

Expression of TROP2 protein was detected by immunohistochemistry with a self-made anti-TROP2 antibody in laryngeal SCC tissue microarrays.

RESULTS

Elevated expression of TROP2 was detected in laryngeal SCC tissues compared with adjacent noncancerous tissues. TROP2 expression in laryngeal SCC was related to tumor differentiation (p = .0001) and lymph node metastasis (p = .0352). Cox regression analyses confirmed that TROP2 expression (p = .015), lymph node metastasis (p = .001), degree of differentiation (p = .002), tumor site (p = .021), and T classification (p = .003) were independent prognostic factors.

CONCLUSIONS

TROP2 can be used as an independent prognostic indicator for laryngeal SCC.

Overexpressing the CCL2 chemokine in an epithelial ovarian cancer cell line results in latency of in vivo tumourigenicity

The frequent loss of heterozygosity of chromosome (Chr) 17 in epithelial ovarian cancer (EOC), particularly high-grade ovarian serous carcinomas (HGOSCs), has been attributed to the disruption of known tumour suppressor genes, such as TP53 (17p13), as well as other genes on this chromosome that alone or in combination have a role in EOC. In a transcriptome analysis of Chr17 genes, we observed significant underexpression of the chemokine CCL2 (17q12) in a small set of HGOSC samples relative to normal ovarian surface epithelial cells and a significant upregulation of CCL2 in the TP53-mutated OV-90 EOC cell line rendered non-tumourigenic as a consequence of genetic manipulation. Here, we report that overexpressing CCL2 in OV-90 resulted in latency of tumour formation at intraperitoneal (i.p.) but not subcutaneous sites in a mouse xenograft model. Overexpressing CCL2 affected cell morphology and exerted modest, but not significant effects on cell viability, colony formation and cell migration. We report significant underexpression of CCL2 by transcriptome analysis (P=0.015) and by immunohistochemistry in 77% of HGOSC samples (n=65). Absent or a very low level of protein expression by immunohistochemistry was also observed in 71% of additional HGOSC samples (n=122). However, CCL2 protein expression did not significantly correlate with overall or disease-free survival. The epithelial cells of normal fallopian tubes, a purported origin of HGOSC, exhibited expression of CCL2 protein by immunohistochemistry. Our results affirm that CCL2 underexpression is a significant feature of HGOSC samples, and that CCL2 overexpression in an EOC cell line model affects tumourigenic potential in the i.p. setting.

Linking epithelial-to-mesenchymal-transition and epigenetic modifications

Cancer, as well as other human disorders, has long been considered to result from the consequence of genetic mutations in key regulatory genes that reside in pathways controlling proliferation, cellular differentiation, DNA damage and repair. In the case of cancer, mutations are well documented to arise in key oncogenes and critically important tumor-suppressor genes as part of the disease progression process. In addition to more accepted, genetic mutations, a rapidly increasing body of evidence supports the general view that profound alterations also occur in 'epigenes', whose products serve to define the 'epigenetic landscape' of tumor cells. Aberrant changes in epigenetic mechanisms such as DNA methylation, histone modifications and expression of micro RNAs play an important role in cancer and contribute to malignant transitions. Here we review recent studies linking epigenetic mechanisms to epithelial-to-mesenchymal transition as defined in normal processes, as well as abnormal transitions that lead to oncogensis.

Epigenetics of solid cancer stem cells

Epigenetics is an emerging science that can help to explain carcinogenesis. The possibility that carcinogenesis may originate in a stem cell process was proposed recently. Stem cells are generated and contribute to tumor formation during the process of tumor development. This chapter focuses on the role of epigenetics and genetics in stem cell formation, different theories about the origin of cancer stem cells (CSCs), and epigenetic mechanisms that occur in solid CSCs. Potential applications of knowledge gained through this field and future prospects for cancer treatment also are discussed.

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.

Prognostic value of MAGE-A and NY-ESO-1 expression in pharyngeal cancer

BACKGROUND

The prognostic value of cancer testis antigens in pharyngeal cancer is understudied.

METHODS

We recruited 90 patients who were treated for pharyngeal cancer. Monoclonal antibodies 57B and B9.8.1.1 were used for detection of MAGE-A and NY-ESO-1 genes.

RESULTS

MAGE-A and NY-ESO-1 gene products were detectable in 70.0% and 33.3% of pharyngeal tumors, respectively. No correlation was established between MAGE-A and NY-ESO-1 expression and TNM staging at presentation. Survival analysis showed a trend toward a shorter 5-year disease-free survival in the group of patients with MAGE-A-positive tumors (log-rank test, p = .122). In contrast, a trend toward a prolonged 5-year disease-free survival was observed in the group of patients with NY-ESO-1-positive tumors (log-rank test, p = .219).

CONCLUSION

In a large population of patients with pharyngeal cancer and available 5-year survival data, prognosis tended to be poorer with MAGE-A expression and better with NY-ESO-1 expression, but the correlations did not reach statistical significance.

Epigenetics of renal cell carcinoma: the path towards new diagnostics and therapeutics

Aberrant DNA methylation, in particular promoter hypermethylation and transcriptional silencing of tumor suppressor genes, has an important role in the development of many human cancers, including renal cell carcinoma (RCC). Indeed, apart from mutations in the well studied von Hippel-Lindau gene (VHL), the mutation frequency rates of known tumor suppressor genes in RCC are generally low, but the number of genes found to show frequent inactivation by promoter methylation in RCC continues to grow. Here, we review the genes identified as epigenetically silenced in RCC and their relationship to pathways of tumor development. Increased understanding of RCC epigenetics provides new insights into the molecular pathogenesis of RCC and opportunities for developing novel strategies for the diagnosis, prognosis and management of RCC.

Decitabine

The pyrimidine analogs, 5-azacytidine (azacitidine, Vidaza) and its deoxy derivative, 5-aza-2'-deoxycytidine (decitabine, Dacogen, are the most widely used inhibitors of DNA methylation which trigger demethylation leading to a consecutive reactivation of epigenetically silenced tumor suppressor genes in vitro and in vivo. Although the antileukemic capacity of decitabine has been known for almost 40 years, its therapeutic potential in hematologic malignancies is still under intensive investigation. Multiple clinical trials have shown the promising activity of low-dose decitabine in AML, MDS, CML, and hemoglobinopathies, whereas its efficacy in solid tumors is rather limited.Clinical responses appear to be induced by both epigenetic alterations and the induction of cell-cycle arrest and/or apoptosis. Recent clinical trials have been investigating new dosing schedules, routes of administration, and combination of decitabine with other agents, including histone deacetylase (HDAC) inhibitors.

Epigenetics and cancer treatment

In addition to the genetic alterations, observed in cancer cells, are mitotically heritable changes in gene expression not encoded by the DNA sequences, which are referred to as epigenetic changes. DNA methylation is among the most studied epigenetic mechanisms together with various histone modifications involved in chromatin remodeling. As opposed to genetic lesions, the epigenetic changes are potentially reversible by a number of small molecules, known as epi-drugs. This review will focus on the biological mechanisms underlying the epigenetic silencing of tumor suppressor genes observed in cancer cells, and the targeted molecular strategies that have been investigated to reverse these aberrations. In particular, we will focus on DNA methyltransferases (DNMTs) and histone deacetylases (HDACs) as epigenetic targets for cancer treatment. A synergistic effect of a combined use of DNMT and HDAC inhibitors has been observed. Moreover, epi-drugs sensitize multiple different cancer cells to a large variety of other treatment strategies. In particular, we have focused on the ability of DNMT and HDAC inhibitors to restore the estrogen receptor alpha (ERalpha) activity in breast cancer. Finally, we will discuss the potential of DNA methylation changes as biomarkers to be used in diverse areas of cancer treatment, especially for predicting response to treatment with DNMT and HDAC inhibitors.

PCR-based methods for detecting single-locus DNA methylation biomarkers in cancer diagnostics, prognostics, and response to treatment

BACKGROUND

DNA methylation is a highly characterized epigenetic modification of the human genome that is implicated in cancer. The altered DNA methylation patterns found in cancer cells include not only global hypomethylation but also discrete hypermethylation of specific genes. In particular, numerous tumor suppressor genes undergo epigenetic silencing because of hypermethylated promoter regions. Some of these genes are considered promising DNA methylation biomarkers for early cancer diagnostics, and some have been shown to be valuable for predicting prognosis or the response to therapy.

CONTENT

PCR-based methods that use sodium bisulfite-treated DNA as a template are generally accepted as the most analytically sensitive and specific techniques for analyzing DNA methylation at single loci. A number of new methods, such as methylation-specific fluorescent amplicon generation (MS-FLAG), methylation-sensitive high-resolution melting (MS-HRM), and sensitive melting analysis after real-time methylation-specific PCR (SMART-MSP), now complement the traditional PCR-based methods and promise to be valuable diagnostic tools. In particular, the HRM technique shows great potential as a diagnostic tool because of its closed-tube format and cost-effectiveness.

SUMMARY

Numerous traditional and new PCR-based methods have been developed for detecting DNA methylation at single loci. All have characteristic advantages and disadvantages, particularly with regard to use in clinical settings.

Detection of MAGE and SSX gene expressions by RT-nested PCR using common primers in head and neck cancer

Objectives

The melanoma antigen gene (MAGE) and synovial sarcoma on X chromosome (SSX) gene families are silent in most normal adult tissues, but are expressed in a variety of malignant lesions. Therefore, detection of MAGE and SSX transcription may be useful for the diagnosis of head and neck cancers. The aim of this study is to detect MAGE and SSX gene transcripts of head and neck cancers using the MAGE 1-6 assay and the SSX 1-9 assay.

Methods

The transcripts of MAGE 1-6 and SSX 1-9 genes were detected by the MAGE 1-6 assay and the SSX 1-9 assay respectively, in cancer cell lines, cancer tissue, and induced sputum specimens from head and neck cancer patients.

Results

The transcripts of MAGE 1-6 and SSX 1-9 genes were detected in 82.8% and 75.9% of head and neck cancer tissues (N=29) respectively, and 96.6% of cancer tissues expressed at least one of MAGE 1-6 or SSX 1-9 genes. In the induced sputum of head and neck cancer patients (N=18), the transcripts of MAGE 1-6 and SSX 1-9 genes were detected in 72.2% and 77.8%, respectively, and 94.4% of the sputum specimens were positive for either the MAGE 1-6 or the SSX 1-9 assay.

Conclusion

These results suggest that the combination of MAGE 1-6 and SSX 1-9 assays may be useful in the diagnosis of head and neck cancer.

Identification of a common HLA-A*0201-restricted epitope among SSX family members by mimicking altered peptide ligands strategy

The synovial sarcoma X breakpoint (SSX) gene family contains nine members. The SSX proteins are CT (cancer/testis) antigens and can be expressed in many tumor types. T cell immune response against SSX protein can be detected in tumor patients and mice expressing any SSX. Screening predominant protective epitopes might improve the low immunogenicity against these "self" CT antigens. Herein, we predicted HLA-A*0201-restricted epitopes for all nine SSX family members, followed by validation with epitope molecular modeling, peptide/HLA-A*0201 affinity, and binding stability assays. We obtained four highly homologous candidate epitopes with the high immunogenicity scores designated P1, P4, P5 and P6, from the nine SSX members. Each of the four candidates could elicit strong epitope-specific CTL immune responses, but P4 could evoke more interferon gamma (IFN-gamma)-producing T cells and more potent CTLs that could lyse more target cells. Importantly, almost all of the four epitopes induced CTLs could cross-lyse the mutual targets both in vitro in human PBMCs and HLA-A2.1/K(b) transgenic mice, but P4 showed superiority to other epitopes in term of cross-cytolysis. All of these results demonstrate that P4 can induce anti-tumor immunity in a fashion superior to other candidates, and may be the "common" CTL epitope among all SSX-expressing tumors. Due to its documented responses herein, P4 has potential application in peptide-mediated immunotherapy.

Cancer epigenomics: DNA methylomes and histone-modification maps

An altered pattern of epigenetic modifications is central to many common human diseases, including cancer. Many studies have explored the mosaic patterns of DNA methylation and histone modification in cancer cells on a gene-by-gene basis; among their results has been the seminal finding of transcriptional silencing of tumour-suppressor genes by CpG-island-promoter hypermethylation. However, recent technological advances are now allowing cancer epigenetics to be studied genome-wide - an approach that has already begun to provide both biological insight and new avenues for translational research. It is time to 'upgrade' cancer epigenetics research and put together an ambitious plan to tackle the many unanswered questions in this field using epigenomics approaches.

C35 (C17orf37) is a novel tumor biomarker abundantly expressed in breast cancer

Identification of shared tumor-specific targets is useful in developing broadly applicable therapies. In a study designed to identify genes up-regulated in breast cancer, a cDNA clone corresponding to a novel gene C35 (C17orf37) was selected by representational difference analysis of tumor and normal human mammary cell lines. Abundant expression of C35 transcript in tumors was confirmed by Northern blot and real-time PCR. The C35 gene is located on chromosome 17q12, 505 nucleotides from the 3' end of the ERBB2 oncogene, the antigenic target for trastuzumab (Herceptin) therapy. The chromosomal arrangement of the genes encoding C35 and ERBB2 is tail to tail. An open reading frame encodes a 12-kDa protein of unknown function. Immunohistochemical analysis detected robust and frequent expression of C35 protein, including 32% of grade 1 and 66% of grades 2 and 3 infiltrating ductal carcinomas of the breast (in contrast to 20% overexpressing HER-2/neu), 38% of infiltrating lobular carcinoma (typically HER-2/neu negative), as well as tumors arising in other tissues. C35 was not detected in 38 different normal human tissues, except Leydig cells in the testes and trace levels in a small percentage of normal breast tissue samples. The distinct and favorable expression profile of C35 spanning early through late stages of disease, including high frequency of overexpression in various breast carcinoma, abundant expression in distant metastases, and either absence or low level expression in normal human tissues, warrants further investigation of the relevance of C35 as a biomarker and/or a target for development of broadly applicable cancer-specific therapies.

Identification of a new HLA-A*0201-restricted cytotoxic T lymphocyte epitope from CML28

Identification of cytotoxic T lymphocyte (CTL) epitopes from additional tumor antigens is essential for the development of specific immunotherapy of malignant tumors. CML28, a recently discovered cancer-testis (CT) antigen from chronic myelogenous leukemia, is considered to be a promising target of tumor-specific immunotherapy. Because HLA-A*0201 is one of the most common histocompatibility molecule in Chinese, we aim at identifying CML28 peptides presented by HLA-A*0201. A panel of CML28-derived antigenic peptides was predicted using a computer-based program. Four peptides with highest predicted score were synthesized and tested for their binding affinities to HLA-A*0201 molecule. Then these peptides were assessed for their immunogenicity to elicit specific immune responses mediated by CTLs both in vitro, from PBMCs sourced from four healthy HLA-A*0201(+) donors, and in vivo, in HLA-A*0201 transgenic mice. One of the tested peptides, CML28((173-181)), induced peptide-specific CTLs in vitro as well as in vivo, which could specifically secrete IFN-gamma and lyse major histocompatibility complex (MHC)-matched tumor cell lines endogenously expressing CML28 antigen and CML28((173-181) )pulsed Jurkat-A2/Kb cells, respectively. These results demonstrate that CML28((173-181) )is a naturally processed and presented CTL epitope with HLA-A*0201 motif and has a promising immunogenicity both in vitro and in vivo. As CML28 is expressed in a large variety of histological tumors besides chronic myelogenous leukemia, we propose that the newly identified epitope, CML28((173-181)), would be of potential use in peptide-based, cancer-specific immunotherapy against a broad spectrum of tumors.

Characterization of a cancer/testis (CT) antigen gene family capable of eliciting humoral response in cancer patients

Cancer/testis (CT) antigens are immunogenic proteins expressed in normal gametogenic tissues and in different types of tumors. CT antigens are promising candidates for cancer immunotherapy, and the identification of novel CT antigens is a prerequisite for the development of cancer vaccines. We have identified a CT antigen, named CTSP-1, with partial similarity to the breast differentiation antigen NY-BR-1. CTSP-1 presents several splicing and polyadenylation variants and has a very restricted expression pattern among normal tissues. CTSP-1 is exclusively expressed in normal testis and is aberrantly expressed in 47.6% (10 of 21) of tumor cell lines and in 44.4% (75 of 169) of tumors from different histological types. The highest percentages of positive expression were observed in melanomas (59.0%) followed by prostate (58.0%) and lung (57.0%) tumors. CTSP-1 is part of a highly conserved gene family, and members of this family also have a restricted expression pattern and similar protein structure. Antibodies against members of this gene family were detected in 10% (14 of 141) of plasma samples from patients with a wide spectrum of tumors. The highest percentages of antibody response were observed in patients with prostate (20.8%), thyroid (20.0%), and breast (16.6%) tumors. Because of its very restricted expression pattern in normal tissues and immunogenicity in different types of tumors, CTSP-1 should be considered a promising candidate for cancer immunotherapy.

Regulation of clustered gene expression by cofactor of BRCA1 (COBRA1) in breast cancer cells

Eucaryotic genes that are coordinately expressed tend to be clustered. Furthermore, gene clusters across chromosomal regions are often upregulated in various tumors. However, relatively little is known about how gene clusters are coordinately expressed in physiological or pathological conditions. Cofactor of BRCA1 (COBRA1), a subunit of the human negative elongation factor, has been shown to repress estrogen-stimulated transcription of trefoil factor 1 (TFF1 or pS2) by stalling RNA polymerase II. Here, we carried out a genome-wide study to identify additional physiological target genes of COBRA1 in breast cancer cells. The study identified a total of 134 genes that were either activated or repressed upon small hairpin RNA-mediated reduction of COBRA1. Interestingly, many COBRA1-regulated genes reside as clusters on the chromosomes and have been previously implicated in cancer development. Detailed examination of two such clusters on chromosome 21 (21q22) and chromosome X (Xp11) reveals that COBRA1 is physically associated with a subset of its regulated genes in each cluster. In addition, COBRA1 was shown to regulate both estrogen-dependent and -independent transcription of the gene cluster at 21q22, which encompasses the previously identified COBRA1-regulated TFF1 (pS2) locus. Thus, COBRA1 plays a critical role in the regulation of clustered gene expression at preferred chromosomal domains in breast cancer cells.

Preferential nuclear and cytoplasmic NY-BR-1 protein expression in primary breast cancer and lymph node metastases

PURPOSE

NY-BR-1 is a recently isolated differentiation antigen, which is expressed in normal mammary tissue and in breast cancer. However, current data are based on RT-PCR analysis and nothing is known about the presence of NY-BR-1 on a protein level. We previously generated a monoclonal antibody to NY-BR-1 to study the protein expression of NY-BR-1.

METHODS

In our immunohistochemical study, NY-BR-1 was analyzed in normal tissues, various tumor types, 124 primary breast cancers, and 37 paired lymph node metastases.

RESULTS

Among normal tissues, NY-BR-1 was present solely in ductal epithelium of the breast. In tumors, carcinoma in situ and invasive carcinoma of the breast were NY-BR-1 positive whereas other tumors and normal tissues were negative. Sixty percent of invasive breast carcinomas were NY-BR-1 positive, displaying cytoplasmic and/or nuclear immunoreactivity. This coexpression was verified by confocal microscopy. Although the monoclonal antibody identified intratumoral heterogeneity, a majority (72%) of NY-BR-1-positive carcinomas revealed immunoreactivity in >50% of the tumor cells. NY-BR-1 expression was more frequent in estrogen receptor-positive and lymph node-negative primary carcinomas (P < 0.05 each) and was more common in grade 1 (77%) than in grade 2 (63%) or grade 3 (50%) carcinomas (P < 0.05). This suggests that NY-BR-1 expression is lost with tumor progression. Forty-nine percent of lymph node metastases were NY-BR-1 positive.

CONCLUSION

This study supports the notion that NY-BR-1 is a differentiation antigen of the breast, which is present in normal and tumorous mammary epithelium. The organ-specific expression of NY-BR-1 and its high prevalence in metastases indicate that it could be a valuable target for cancer immunotherapy.

Cancer testis antigens--their importance in immunotherapy and in the early detection of cancer

The development of successful immunotherapeutic strategies requires the identification and characterisation of immunogenic cancer antigens that will be recognised by the host immune system, leading to tumour rejection. The concept of immunotherapy is based on the assumption that antigenic structures expressed in tumours can be used for therapeutic approaches employing the autologous immune system or by the application of immunotherapeutic reagents. Based on this concept, there is a great need to gain profound knowledge of the actual protein/antigen expression and its distribution pattern within normal tissues and cancerous tissues. Cancer testis (CT) antigens represent a unique class of tumour antigens, which are expressed in a variety of cancerous tissues and are silent in normal tissues, except for the testis. Owing to their restricted gene expression in the testis and various malignancies, CT antigens represent potential defined targets for antigen-based vaccination and antigen-directed immunotherapy to control cancer growth. Moreover, the analysis of humoral and cellular immune responses to CT antigens has proved useful for identifying novel cancer serum biomarkers with potential implications in early diagnosis of cancer.

Overexpression of the Doppel protein in acute myeloid leukaemias and myelodysplastic syndromes

We investigated the expression patterns and distribution of Doppel (Dpl), the product of the prion-like gene PRND, in the leukaemic cell lines HL-60 and K562 and in bone marrow cells from 44 patients with acute myeloid leukaemia (AML) and 63 patients with myelodysplastic syndrome (MDS). Whereas normal samples were negative or showed very weak expression that was restricted to CD34(+) cells, Dpl was detected in both cell lines and in most AML and MDS cases by immunocytochemistry and Western blotting. Quantitative reverse transcription polymerase chain reaction revealed variable mRNA levels in almost all AML and MDS cases, but barely detectable levels in normal bone marrow. These differences were confirmed by in situ hybridization. PRND expression was higher in advanced compared with early MDS (P = 0.01), but Dpl levels did not predict disease progression. In AML there was no correlation between Dpl levels and clinical or laboratory findings. In conclusion, this is the first time that the expression of PRND has been demonstrated in human bone marrow. The molecular mechanism of the observed overexpression is unknown; however, the differential Dpl distribution in AML and MDS versus healthy subjects makes it a possible leukaemia-associated antigen that could be useful for diagnostic and therapeutic purposes.

Immunohistochemical analysis of the expression of FATE/BJ-HCC-2 antigen in normal and malignant tissues

FATE/BJ-HCC-2 is a newly identified cancer/testis (CT) antigen, which was detected in tumor tissues and testis. As previous studies of FATE/BJ-HCC-2 expression pattern were mainly based on messenger RNA (mRNA) analysis, it is necessary to investigate its actual protein expression pattern in tumor tissues for the evaluation of its application value. In this study, we produced specific polyclonal antibody (pAb) to the recombinant FATE/BJ-HCC-2 protein and analyzed the FATE/BJ-HCC-2 antigen expression in normal and malignant tissues by the immunohistochemical approach. The results showed that there was no detectable FATE/BJ-HCC-2 antigen expressed in normal tissues except testis. In hepatocellular carcinoma (HCC) tissues, the FATE/BJ-HCC-2 antigen was detected in 20% (7/35) specimens. All samples that expressed the FATE/BJ-HCC-2 antigen were of poorly or moderately differentiated HCC. The stained antigen was located in the cytoplasm and the staining pattern showed heterogeneity from focal to more than 40% of the tumor cells. The FATE/BJ-HCC-2 antigen was also expressed in other tumor tissues. The results of [3H]thymidine incorporation showed that FATE/BJ-HCC-2 protein enhanced tumor cell proliferation after transfection of FATE/BJ-HCC-2 gene in HCC cell line (P<0.01). This effect could be specifically blocked by anti-FATE/BJ-HCC-2 pAb. Serological screening showed that the antibody specific to the FATE/BJ-HCC-2 antigen was detected in 7.7% (4/52) patients. Notably, the four positive patients bore poorly or moderately differentiated HCC. FATE/BJ-HCC-2 mRNA transcript was detected in the peripheral blood mononuclear cells (PBMCs) of 46.67% patients whose resected HCC tissue samples were positive for FATE/BJ-HCC-2 mRNA, which implicated tumor cell dissemination in blood circulation and may relate to the metastasis of HCC. Thus, FATE/BJ-HCC-2 may be a valuable candidate CT antigen for polyvalent vaccines in tumor immunotherapy and an assisting diagnostic marker for prognosis of the disease.

Molecular profiling of hepatocellular carcinomas by cDNA microarray

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world. Conventional diagnosis and treatment of this malignancy have been dismal and should be complemented by novel tools. The development and progress of HCC are believed to be caused by the accumulation of genetic changes resulting in altered expression of thousands of cancer-related genes, which can be measured by globe genetic analysis. Gene expression profiling of HCC has been employed to elucidate hepatocarcinogenesis and disclose molecular mechanisms underlying complex clinical features. Identifying phenotype-associated genes/profiles has impacts on current diagnosis and management strategy of HCC. In spite of some pitfalls of this technology and challenges in improving the research process, scrutinous validation of profiling data of HCC combined with other approaches will eventually benefit the patients.

Novel perspective: focusing on the X chromosome in reproductive cancers

In an XX female, one of the two X chromosomes has been inactivated during early embryonic life to achieve a compensation of X-linked gene products between males and females, leaving only one allele of X-linked genes functional. There are some X-linked genes escaping the X-inactivation, i.e., being expressed from both alleles. Escape from X-inactivation varies at different levels; some genes have both alleles active in some women but only one allele active in others, whereas some other genes have both alleles active in neoplastic tissue but only one allele active normally. The X-inactivation may be considered functionally equivalent to a loss of heterozygosity (LOH) for some genes, whereas escape from X-inactivation may be equivalent to functional gene amplification for others. The physiological LOH may make X-linked tumor suppressor genes lose their function more easily, compared with autosomal tumor suppressor genes, thus predisposing women to cancer formation more easily. Moreover, the human X chromosome contains many genes related to cancer or to sex and reproduction. All these properties of the X chromosome suggest that it may play more important roles than any autosomal chromosome in the development and progression of reproductive and urologic cancers.

Immune responses in cancer

The complex of humoral factors and immune cells comprises two interleaved systems, innate and acquired. Immune cells scan the occurrence of any molecule that it considers to be nonself. Transformed cells acquire antigenicity that is recognized as nonself. A specific immune response is generated that results in the proliferation of antigen-specific lymphocytes. Immunity is acquired when antibodies and T-cell receptors are expressed and up-regulated through the formation and release of lymphokines, chemokines, and cytokines. Both innate and acquired immune systems interact to initiate antigenic responses against carcinomas. A new approach to the treatment of cancer has been immunotherapy, which aims to up-regulate the immune system in order that it may better control carcinogenesis. Currently, several forms of immunotherapy that use natural biological substances to activate the immune system are being explored therapeutically. The various forms of immunotherapy fall into three main categories: monoclonal antibodies, immune response modifiers, and vaccines. While these modalities have individually shown some promise, it is likely that the best strategy to combat cancer may require multiple immunotherapeutic strategies in order to demonstrate benefit in different patient populations. It may be that the best results are obtained with vaccines in combination with a variety of immunotherapy combinations. Another potent strategy may be in combining with more traditional cancer drugs as evidenced from the benefit derived from enhancing the efficacy of chemotherapy with cytokines. Through such concerted efforts, a durable, therapeutic antitumour immune response may be achieved and maintained over the course of a patient's lifespan.