Expression of cancer-testis antigens in hepatocellular carcinoma

Cancer/testis antigens: from serology to mRNA cancer vaccine

Cancer/testis antigens (CTAs) are a group of tumor antigens expressed in numerous cancer tissues, as well as in the testis and placental tissues. There are over 200 CTAs supported by serology and expression data. The expression patterns of CTAs reflect the similarities between the processes of gametogenesis and tumorigenesis. It is notable that CTAs are highly expressed in three types of cancers (lung cancer, bladder cancer, and skin cancer), all of which have a metal etiology. Here, we review the expression, regulation, and function of CTAs and their translational prospects as cancer biomarkers and treatment targets. Many CTAs are highly immunogenic, tissue-specific, and frequently expressed in cancer tissues but not under physiological conditions, rendering them promising candidates for cancer detection. Some CTAs are associated with clinical outcomes, so they may serve as prognostic biomarkers. A small number of CTAs are membrane-bound, making them ideal targets for chimeric antigen receptor (CAR) T cells. Mounting evidence suggests that CTAs induce humoral or cellular immune responses, providing cancer immunotherapeutic opportunities for T-cell receptors (TCRs), CAR T cell, antibody-based therapy and peptide- or mRNA-based vaccines. Indeed, CTAs are the dominating non-mutated targets in mRNA cancer vaccine development. Clinical trials on CTA TCR and vaccines have shown effectiveness, safety, and tolerance, but these successes are limited to a small number of patients. In-depth studies on CTA expression and function are needed to improve CTA-based immunotherapy.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Vaccinia-based oncolytic immunotherapy Pexastimogene Devacirepvec in patients with advanced hepatocellular carcinoma after sorafenib failure: a randomized multicenter Phase IIb trial (TRAVERSE)

Pexastimogene devacirepvec (Pexa-Vec) is a vaccinia virus-based oncolytic immunotherapy designed to preferentially replicate in and destroy tumor cells while stimulating anti-tumor immunity by expressing GM-CSF. An earlier randomized Phase IIa trial in predominantly sorafenib-naïve hepatocellular carcinoma (HCC) demonstrated an overall survival (OS) benefit. This randomized, open-label Phase IIb trial investigated whether Pexa-Vec plus Best Supportive Care (BSC) improved OS over BSC alone in HCC patients who failed sorafenib therapy (TRAVERSE).

129 patients were randomly assigned 2:1 to Pexa-Vec plus BSC vs. BSC alone. Pexa-Vec was given as a single intravenous (IV) infusion followed by up to 5 IT injections. The primary endpoint was OS. Secondary endpoints included overall response rate (RR), time to progression (TTP) and safety.

A high drop-out rate in the control arm (63%) confounded assessment of response-based endpoints. Median OS (ITT) for Pexa-Vec plus BSC vs. BSC alone was 4.2 and 4.4 months, respectively (HR, 1.19, 95% CI: 0.78–1.80; p = .428). There was no difference between the two treatment arms in RR or TTP. Pexa-Vec was generally well-tolerated. The most frequent Grade 3 included pyrexia (8%) and hypotension (8%). Induction of immune responses to vaccinia antigens and HCC associated antigens were observed.

Despite a tolerable safety profile and induction of T cell responses, Pexa-Vec did not improve OS as second-line therapy after sorafenib failure. The true potential of oncolytic viruses may lie in the treatment of patients with earlier disease stages which should be addressed in future studies.

ClinicalTrials.gov: NCT01387555

Application of cancer-testis antigens in immunotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a worldwide common malignancy with poor prognosis. Several studies have aimed at identification of appropriate biomarkers for early detection of this cancer. Cancer-testis antigens (CTAs) as a novel group of tumor-associated antigens have been demonstrated to be expressed in HCC samples as well as peripheral blood samples from these patients but not in the corresponding adjacent noncancerous samples. Such pattern of expression has provided them an opportunity to be used as immunotherapeutic targets. The detection of spontaneous immune responses against CTAs in HCC patients has prompted design of CTA-based immunotherapeutic protocols in these patients. The results of some clinical trials have been promising in a subset of patients.

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.

Trial watch: Naked and vectored DNA-based anticancer vaccines

One type of anticancer vaccine relies on the administration of DNA constructs encoding one or multiple tumor-associated antigens (TAAs). The ultimate objective of these preparations, which can be naked or vectored by non-pathogenic viruses, bacteria or yeast cells, is to drive the synthesis of TAAs in the context of an immunostimulatory milieu, resulting in the (re-)elicitation of a tumor-targeting immune response. In spite of encouraging preclinical results, the clinical efficacy of DNA-based vaccines employed as standalone immunotherapeutic interventions in cancer patients appears to be limited. Thus, efforts are currently being devoted to the development of combinatorial regimens that allow DNA-based anticancer vaccines to elicit clinically relevant immune responses. Here, we discuss recent advances in the preclinical and clinical development of this therapeutic paradigm.

OY-TES-1 may regulate the malignant behavior of liver cancer via NANOG, CD9, CCND2 and CDCA3: a bioinformatic analysis combine with RNAi and oligonucleotide microarray

Given its tumor-specific expression, including liver cancer, OY-TES-1 is a potential molecular marker for the diagnosis and immunotherapy of liver cancers. However, investigations of the mechanisms and the role of OY-TES-1 in liver cancer are rare. In the present study, based on a comprehensive bioinformatic analysis combined with RNA interference (RNAi) and oligonucleotide microarray, we report for the first time that downregulation of OY-TES-1 resulted in significant changes in expression of NANOG, CD9, CCND2 and CDCA3 in the liver cancer cell line BEL-7404. NANOG, CD9, CCND2 and CDCA3 may be involved in cell proliferation, migration, invasion and apoptosis, yet also may be functionally related to each other and OY-TES-1. Among these molecules, we identified that NANOG, containing a Kazal-2 binding motif and homeobox, may be the most likely candidate protein interacting with OY-TES-1 in liver cancer. Thus, the present study may provide important information for further investigation of the roles of OY-TES-1 in liver cancer.

Trial watch: DNA vaccines for cancer therapy

The foundation of modern vaccinology dates back to the 1790s, when the English physician Edward Jenner uncovered the tremendous medical potential of prophylactic vaccination. Jenner’s work ignited a wave of nationwide vaccination campaigns abating the incidence of multiple life-threatening infectious diseases and culminating with the eradication of natural smallpox virus, which was definitively certified by the WHO in 1980. The possibility of using vaccines against cancer was first proposed at the end of the 19th century by Paul Ehrlich and William Coley. However, it was not until the 1990s that such a hypothesis began to be intensively investigated, following the realization that the immune system is not completely unresponsive to tumors and that neoplastic cells express immunogenic tumor-associated antigens (TAAs). Nowadays, anticancer vaccines are rapidly moving from the bench to the bedside, and a few prophylactic and therapeutic preparations have already been approved by FDA for use in humans. In this setting, one interesting approach is constituted by DNA vaccines, i.e., TAA-encoding circularized DNA constructs, often of bacterial origin, that are delivered to patients as such or by means of specific vectors, including (but not limited to) liposomal preparations, nanoparticles, bacteria and viruses. The administration of DNA vaccines is most often performed via the intramuscular or subcutaneous route and is expected to cause (1) the endogenous synthesis of the TAA by myocytes and/or resident antigen-presenting cells; (2) the presentation of TAA-derived peptides on the cell surface, in association with MHC class I molecules; and (3) the activation of potentially therapeutic tumor-specific immune responses. In this Trial Watch, we will summarize the results of recent clinical trials that have evaluated/are evaluating DNA vaccines as therapeutic interventions against cancer.

RNA interference against cancer/testis genes identifies dual specificity phosphatase 21 as a potential therapeutic target in human hepatocellular carcinoma

Cancer/testis (CT) antigens have been considered therapeutic targets for treating cancers. However, a central question is whether their expression contributes to tumorigenesis or if they are functionally irrelevant by-products derived from the process of cellular transformation. In any case, these CT antigens are essential for cancer cell survival and may serve as potential therapeutic targets. Recently, the cell-based RNA interference (RNAi) screen has proven to be a powerful approach for identifying potential therapeutic targets. In this study we sought to identify new CT antigens as potential therapeutic targets for human hepatocellular carcinoma (HCC), and 179 potential CT genes on the X chromosome were screened through a bioinformatics analysis of gene expression profiles. Then an RNAi screen against these potential CT genes identified nine that were required for sustaining the survival of Focus and PLC/PRF/5 cells. Among the nine genes, the physiologically testis-restricted dual specificity phosphatase 21 (DUSP21) encoding a dual specificity phosphatase was up-regulated in 39 (33%) of 118 human HCC specimens. Ectopic DUSP21 had no obvious impact on proliferation and colony formation in HCC cells. However, DUSP21 silencing significantly suppressed cell proliferation, colony formation, and in vivo tumorigenicity in HCC cells. The administration of adenovirus-mediated RNAi and an atelocollagen/siRNA mixture against endogenous DUSP21 significantly suppressed xenograft HCC tumors in mice. Further investigations showed that DUSP21 knockdown led to arrest of the cell cycle in G1 phase, cell senescence, and expression changes of some factors with functions in the cell cycle and/or senescence. Furthermore, the antiproliferative role of DUSP21 knockdown is through activation of p38 mitogen-activated protein kinase in HCC.

CONCLUSION

DUSP21 plays an important role in sustaining HCC cell proliferation and may thus act as a potential therapeutic target in HCC treatment.

Sperm protein 17, MAGE-C1 and NY-ESO-1 in hepatocellular carcinoma: expression frequency and their correlation with clinical parameters

This study is dedicated to investigate the expression patterns of sperm protein 17 (Sp17), melanoma-specific antigen (MAGE)-C1 and New York esophageal squamous cell carcinoma-1 (NY-ESO-1), to explore the correlation between these cancer-testis antigens and clinical parameters, and to evaluate their values in diagnosis and differentiation of hepatocellular carcinoma.

METHODS

Immunohistochemical staining was performed in 45 paraffin-embedded hepatocellular carcinoma specimens. 45 normal peripheral hepatic tissues collected from adjacent non-cancerous areas were used as controls.

RESULTS

Positive results of immunohistostaining were obtained in 16 (35.6%), 7 (15.6%) and 36 (80.0%) samples using MAGE-C1, NY-ESO-1 and Sp17 antibodies, respectively. The immunoreactivity of Sp17 was also found in 7 (14.0%) control samples. A statistical correlation between the frequency of Sp17 expression and tumor differentiation grade in hepatocellular carcinoma was confirmed.

CONCLUSIONS

Sp17 is highly expressed in hepatocellular carcinoma cells. The frequency of Sp17 expression is closely related to the pathologic differentiation in hepatocellular carcinoma.

FAM9C plays an anti-apoptotic role through activation of the PI3K/Akt pathway in human hepatocellular carcinoma

The function of FAM9C encoding a testis-exclusively expressed and nuclear-localized protein remains unknown. In the present study, we evaluated the role of FAM9C in human hepatocellular carcinoma. We found that among three FAM9 family members, only FAM9C was frequently upregulated in HCC specimens compared with that in corresponding adjacent non-cancer liver tissues. FAM9C was located in the nucleus of HCC cells, as shown by both western blotting and immumofluorescence assays. Significantly, FAM9C overexpression promoted proliferation, clonogenicity in an anchorage-dependent manner, in vivo tumorigenicity of YY-8103, and Huh-7 cells. In contrast, FAM9C knockdown suppressed proliferation, anchorage-dependent colony formation and in vivo tumorigenicity of QGY-7703, and BEL-7404 cells. However, FAM9C had no significant effects on cell cycle progression when FAM9C was stably overexpressed in Huh-7 cells or knocked down in BEL-7404 cells. Most importantly, FAM9C regulated activation of Akt and UV-induced apoptosis in HCC cells. FAM9C overexpression increased the phosphorylation levels of Akt and anti-apoptotic ability of Huh-7 cells, whereas endogenous FAM9C knockdown reduced the phosphorylated levels of Akt and anti-apoptotic ability of BEL-7404 cells. Furthermore, the anti-apoptotic function of FAM9C could be prevented when the PI3K-Akt pathway was in a loss-of-function caused by RNA interference against Akt or PI3K inhibitor LY294002 in HCC cells. Taken together, our data demonstrate that FAM9C as a novel cancer testis gene plays an anti-apoptotic role in human hepatocellular carcinoma through activating the PI3K/Akt signaling pathway, and serves as a promising target for HCC therapy.

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.

Diagnostic value of cancer-testis antigen mRNA in peripheral blood from hepatocellular carcinoma patients

AIM: To evaluate the diagnostic value of cancer-testis antigen (CTA) mRNA in peripheral blood samples from hepatocellular carcinoma (HCC) patients.

METHODS: Peripheral blood samples were taken from 90 patients with HCC before operation. Expression of melanoma antigen-1 (MAGE-1), synovial sarcoma X breakpoint-1 (SSX-1), and cancer-testis-associated protein of 11 kDa (CTp11) mRNA in peripheral blood mononuclear cells (PBMC) was tested by nested reverse transcripts-polymerase chain reaction (RT-PCR). Serum α-fetoprotein (AFP) in these patients was also determined.

RESULTS: The positive rate of MAGE-1, SSX-1 and CTp11 transcripts was 37.7%, 34.4%, 31.1% in PBMC samples, and 74.4%, 73.3%, 62.2% in their resected tumor samples, respectively. The positive rate for at least one of the transcripts of three CTA genes was 66.7% in PBMC samples and 91.1% in their resected tumor samples. MAGE-1, SSX-1 and/or CTp11 mRNA were not detected in the PBMC of those patients from whom the resected tumor samples were MAGE-1, SSX-1 and/or CTp11 mRNA negative, nor in the PBMC samples from 20 healthy donors and 10 cirrhotic patients. Among the 90 patients, the serum AFP in 44 patients met the general diagnostic standard (AFP > 400 μg/L) for HCC, and was negative (AFP ≤ 20 μg/L) or positive with a low concentration (20 μg/L < AFP ≤ 400 μg/L) in the other patients. The positive rate for at least one of the transcripts of three CTA genes in PBMC samples from the AFP negative or positive patients with a low concentration was 69.2% and 45.0%, respectively. Of the 90 patients, 71 (78.9%) were diagnosed as HCC by nested RT-PCR and serum AFP. Although the positive rate for at least one of the transcripts of three CTA genes in PBMC samples from 53 patients at TNM stage III or IV was obviously higher than that in PBMC samples from 37 patients at stage I or II (77.9% vs 51.4%, P = 0.010), the CTA mRNA was detected in 41.7% and 56.0% of PBMC samples from HCC patients at stages I and II, respectively.

CONCLUSION: Detecting MAGE-1, SSX-1 and CTp11 mRNA in PBMC improves the total diagnostic rate of HCC.

Frequent expression of the novel cancer testis antigen MAGE-C2/CT-10 in hepatocellular carcinoma

Cancer testis (CT) antigens are attractive targets for immunotherapy in cancer patients. Immunohistochemistry was used to study the expression of the CT antigens MAGE-C2/CT-10, MAGE-C1/CT-7, GAGE, MAGE-A4 and NY-ESO-1 in 146 hepatocellular carcinomas, 13 intrahepatic cholangiocarcinomas, 37 extrahepatic cholangiocarcinomas and 32 gallbladder carcinomas. Immunopositivity was correlated with clinicopathological parameters, MHC Class 1 expression, intratumoral CD4+, CD8+ and FOXP3+ T cells and CD163+ antigen-presenting cells. Of the 146 hepatocellular carcinomas, 34% were positive for MAGE-C2/CT-10, 12% for MAGE-C1/CT-7, 11% for GAGE and 2% for NY-ESO-1, respectively. MHC Class 1 coexpression was identified in almost all CT antigen-positive tumors. The number of intratumoral FOXP3+ regulatory T cells was increased in CT antigen-positive hepatocellular carcinomas (p<0.004), suggesting inhibition of immune response in such tumors. Furthermore, MAGE-C1/CT-7 and GAGE positivity was correlated with reduced overall survival in patients with hepatocellular carcinoma (p=0.03 and 0.01, respectively). Four (13%) gallbladder carcinomas stained positive for MAGE-C2/CT-10, of which 1 tumor (3%) was also positive for NY-ESO-1 and GAGE. CT antigens were not expressed in intra- and extrahepatic cholangiocarcinomas. Our results suggest that MAGE-C2/CT-10 may be a good candidate for peptide vaccination in patients with hepatocellular carcinoma.

The disease relevance of human hepatocellular xenograft models: molecular characterization and review of the literature

In recent years a number of new therapeutics has been developed that were not general toxins and inhibitors of cell division like classical chemotherapeutics, but were designed to target a specific pathway. A prerequisite for this development was the comprehensive characterization of molecular alterations occurring in human hepatocellular carcinoma (HCC). However, while much knowledge of the molecular pathogenesis of human HCC has been gained, the model systems used to test the functional relevance of these alterations and applied for preclinical evaluation of drug candidates are still poorly characterized. In this paper, we reviewed the literature about several commonly used HCC cell lines and xenotransplantation models and present our own data on the molecular characterization of these. Results obtained demonstrate that it is important to have a sound knowledge of the specific molecular constitution of the experimental model and to carefully evaluate the functional status of the pathway of interest. For this reason, we make the gene expression profiles publicly available to help researchers making an informed decision about which model to use.

Expression of melanoma-associated antigens in oral squamous cell carcinoma

BACKGROUND

Melanoma-associated antigens-A (MAGE-A) are expressed in a variety of tumors but not in normal tissues. Thus, their detection is highly specific to cancer cells, which makes them potential targets for the diagnosis, prognosis and also immunotherapy of neoplastic diseases.

METHODS

To determine the expression pattern and potential role of MAGE-A antigens in oral squamous cell carcinoma (OSCC), expression patterns of MAGE-A1-A6 and A12 were analyzed in 55 OSCC and 20 healthy oral mucosa using high-sensitive reverse transcription-nested polymerase chain reaction (RT-nPCR).

RESULTS

The 85.45% of tumor specimens expressed at least one of these genes. A significant correlation between the expression of MAGE-A1-A6 and A12 and malignancy was ascertained (P = 0.0001). On the contrary, none of the normal mucosal specimens expressed one of the MAGE-A subtypes. Antigen expression did not correlate with clinicopathological parameters, such as TNM classification, grading and clinical stage of OSCC.

CONCLUSIONS

Multiple simultaneous detection of MAGE-A1-A6 and A12 expression has been found to be more specific and sensitive than the detection of single MAGE-A antigen for the diagnostic and prognostic evaluation of OSCC. In addition, monitoring the expression of several MAGE-A subtypes may determine suitable immunotherapeutic targets. Subsequently, coexpressed genes may be warranted for developing polyvalent vaccines.

Biological treatment for liver tumor and new potential biomarkers

The search for effective and efficacious therapy for liver tumor was started many years ago and is still ongoing. Despite all of the surgical advances, much work needs to be done to improve understanding of the biology of the tumor and its treatment. The rules of hepatic surgery are changing because of two recent major trends: (1) technical simplification, and (2) the endeavor to treat an increasing number of patients. T lymphocytes are potent cellular effectors of the immune system and possess a memory that responds to rechallenge by the same antigen. Being more specific and less toxic than chemotherapy, tumor infusion could be an ideal adjuvant therapy for patients with primary and secondary liver malignancies. Moreover, tumor cell vaccines have demonstrated efficacy in terms of minimal residual disease and are being investigated, but the requirement for an adequate supple of autologos tumor may limit the general applicability of these approaches. Various studies have demonstrated the aberrant expression of germ-cell proteins called cancer-testis (CT) antigens in liver neoplastic cells. Their selective normal-tissue expression makes them ideal antigens for immune targeting of malignant disease. Specific expression of CT antigens also suggests their application as tumor markers to detect circulating hepatocellular carcinoma (HCC) cells, as an adjuvant diagnostic tool, and as indicators for recurrence and prognosis. Biological therapy is now generating more clinical trials. More studies need to be performed and further experiments need to be done, although currently this seems a valid pathway for the treatment of liver cancer. Cytoreduction treatment of liver tumor and the vaccine might be the future of the treatment of primary and secondary liver tumor.

BORIS, a paralogue of the transcription factor, CTCF, is aberrantly expressed in breast tumours

BORIS (for brother of the regulator of imprinted sites), a paralogue of the transcription factor, CTCF, is a novel member of the cancer-testis antigen family. The aims of the present study were as follows: (1) to investigate BORIS expression in breast cells and tumours using immunohistochemical staining, western and real-time RT–PCR analyses and (2) assess potential correlation between BORIS levels in tumours with clinical/pathological parameters. BORIS was detected in all 18 inspected breast cell lines, but not in a primary normal breast cell culture. In 70.7% (41 of 58 cases) BORIS was observed in breast tumours. High levels of BORIS correlated with high levels of progesterone receptor (PR) and oestrogen receptor (ER). The link between BORIS and PR/ER was further confirmed by the ability of BORIS to activate the promoters of the PR and ER genes in the reporter assays. Detection of BORIS in a high proportion of breast cancer patients implies potential practical applications of BORIS as a molecular biomarker of breast cancer. This may be important for diagnosis of the condition and for the therapeutic use of BORIS. The ability of BORIS to activate promoters of the RP and ER genes points towards possible involvement of BORIS in the establishment, progression and maintenance of breast tumours.

Mutational analysis of SPANX genes in families with X-linked prostate cancer

BACKGROUND

Previous genetic linkage studies identified a locus for susceptibility to prostate cancer called HPCX at Xq27. The candidate region contains two clusters of SPANX genes. The first cluster called SPANX-A/D includes SPANX-A1, SPANX-A2, SPANX-B, SPANX-C, and SPANX-D; the second cluster called SPANX-N includes SPANX-N1, SPANX-N2, SPANX-N3, and SPANX-N4. The SPANX genes encode cancer-testis (CT) specific antigens. Previous studies identified SPANX-B and SPANX-D variants produced by gene conversion events, none of which are associated with X-linked prostate cancer.

METHODS

In this study we applied transformation-associated recombination cloning (TAR) in yeast to analyze sequence variations in SPANX-A1, SPANX-A2, and SPANX-C genes that are resided within large chromosomal duplications. A SPANX-N1/N4 cluster was analyzed by a routine PCR analysis.

RESULTS

None of the sequence variations in the coding regions of these genes is associated with susceptibility to prostate cancer.

CONCLUSIONS

Therefore, genetic variation in the SPANX genes is not the actual target variants explaining HPCX. However, it is possible that they play a modifying role in susceptibility to prostate cancer through complex recombinational interaction.

Evolutionary diversification of SPANX-N sperm protein gene structure and expression

The sperm protein associated with nucleus in the X chromosome (SPANX) genes cluster at Xq27 in two subfamilies, SPANX-A/D and SPANX-N. SPANX-A/D is specific for hominoids and is fairly well characterized. The SPANX-N gave rise to SPANX-A/D in the hominoid lineage ∼7 MYA. Given the proposed role of SPANX genes in spermatogenesis, we have extended studies to SPANX-N gene evolution, variation, regulation of expression, and intra-sperm localization. By immunofluorescence analysis, SPANX-N proteins are localized in post-meiotic spermatids exclusively, like SPANX-A/D. But in contrast to SPANX-A/D, SPANX-N are found in all ejaculated spermatozoa rather than only in a subpopulation, are localized in the acrosome rather than in the nuclear envelope, and are expressed at a low level in several nongametogenic adult tissues as well as many cancers. Presence of a binding site for CTCF and its testis-specific paralogue BORIS in the SPANX promoters suggests, by analogy to MAGE-A1 and NY-ESO-1, that their activation in spermatogenesis is mediated by the programmed replacement of CTCF by BORIS. Based on the relative density of CpG, the more extended expression of SPANX-N compared to SPANX-A/D in nongametogenic tissues is likely attributed to differences in promoter methylation. Our findings suggest that the recent duplication of SPANX genes in hominoids was accompanied by different localization of SPANX-N proteins in post-meiotic sperm and additional expression in several nongonadal tissues. This suggests a corresponding functional diversification of SPANX gene families in hominoids. SPANX proteins thus provide unique targets to investigate their roles in the function of spermatozoa, selected malignancies, and for SPANX-N, in other tissues as well.

Usefulness of cancer-testis antigens as biomarkers for the diagnosis and treatment of hepatocellular carcinoma

Despite advances in our cellular and molecular knowledge, hepatocellular carcinoma (HCC) remains one of the major public health problems throughout the world. It is now known to be highly heterogeneous: it encompasses various pathological entities and a wide range of clinical behaviors, and is underpinned by a complex array of gene alterations that affect supra-molecular processes.

Four families of HCC tumour markers have been recently proposed: a) onco-fetal and glycoprotein antigens; b) enzymes and iso-enzymes; c) cytokines and d) genes. A category of tumour-associated antigens called cancer-testis (CT) antigens has been identified and their encoding genes have been extensively investigated. CT antigens are expressed in a limited number of normal tissues as well as in malignant tumors of unrelated histological origin, including the liver. Given that cancers are being recognized as increasingly complex, we here review the role of CT antigens as liver tumour biomarkers and their validation process, and discuss why they may improve the effectiveness of screening HCC patients and help in determining the risk of developing HCC.

Immunological treatment of liver tumors

Although multiple options for the treatment of liver tumors have often been described in the past, including liver resection, radiofrequency ablation with or without hepatic pump insertion, laparoscopic liver resection and the use of chemotherapy, the potential of immunotherapy and gene manipulation is still largely unexplored. Immunological therapy by gene manipulation is based on the interaction between virus-based gene delivery systems and dendritic cells. Using viruses as vectors, it is possible to transduce dendritic cells with genes encoding tumor-associated antigens, thus inducing strong humoral and cellular immunity against the antigens themselves. Both chemotherapy and radiation therapy have the disadvantage of destroying healthy cells, thus causing severe side-effects. We need more precisely targeted therapies capable of killing cancer cells while sparing healthy cells. Our goal is to establish a new treatment for solid liver tumors based on the concept of cytoreduction, and propose an innovative algorithm.