Biological functions of melanoma-associated antigens

The Dual Roles of MAGE-C2 in p53 Ubiquitination and Cell Proliferation Through E3 Ligases MDM2 and TRIM28

The tumor suppressor p53 is critical for the maintenance of genome stability and protection against tumor malignant transformation, and its homeostasis is usually regulated by ubiquitination. MDM2 is a major E3 ligase of p53 ubiquitination, and its activity is enhanced by TRIM28. TRIM28 also independently ubiquitinates p53 as an E3 ligase activated by MAGE-C2. Moreover, MAGE-C2 is highly expressed in various cancers, but the detailed mechanisms of MAGE-C2 involved in MDM2/TRIM28-mediated p53 ubiquitination remain unknown. Here, we found that MAGE-C2 directly interacts with MDM2 through its conserved MHD domain to inhibit the activity of MDM2 on p53 ubiquitination. Furthermore, TRIM28 acts as an MAGE-C2 binding partner and directly competes with MAGE-C2 for MDM2 interaction, thus releasing the inhibitory role of MAGE-C2 and promoting p53 ubiquitination. MAGE-C2 suppresses cell proliferation in TRIM28-deficient cells, but the overexpression of TRIM28 antagonizes the inhibitory role of MAGE-C2 and accumulates p53 ubiquitination to promote cell proliferation. This study clarified the molecular link of MAGE-C2 in two major E3 systems MDM2 and TRIM28 on p53 ubiquitination. Our results revealed the molecular function of how MAGE-C2 and TRIM28 contribute to p53 ubiquitination and cell proliferation, in which MAGE-C2 acts as a potential inhibitor of MDM2 and TRIM28 is a vital regulator for MAGE-C2 function in p53 protein level and cell proliferation. This work would be helpful to understand the regulation mechanism of tumor suppressor p53.

On the Cutting Edge of Oral Cancer Prevention: Finding Risk-Predictive Markers in Precancerous Lesions by Longitudinal Studies

Early identification and management of precancerous lesions at high risk of developing cancers is the most effective and economical way to reduce the incidence, mortality, and morbidity of cancers as well as minimizing treatment-related complications, including pain, impaired functions, and disfiguration. Reliable cancer-risk-predictive markers play an important role in enabling evidence-based decision making as well as providing mechanistic insight into the malignant conversion of precancerous lesions. The focus of this article is to review updates on markers that may predict the risk of oral premalignant lesions (OPLs) in developing into oral squamous cell carcinomas (OSCCs), which can logically be discovered only by prospective or retrospective longitudinal studies that analyze pre-progression OPL samples with long-term follow-up outcomes. These risk-predictive markers are different from those that prognosticate the survival outcome of cancers after they have been diagnosed and treated, or those that differentiate between different lesion types and stages. Up-to-date knowledge on cancer-risk-predictive markers discovered by longitudinally followed studies will be reviewed. The goal of this endeavor is to use this information as a starting point to address some key challenges limiting our progress in this area in the hope of achieving effective translation of research discoveries into new clinical interventions.

MAGE genes encoding for embryonic development in cattle is mainly regulated by zinc finger transcription factor family and slightly by CpG Islands

Background

Melanoma Antigen Genes (MAGEs) are a family of genes that have piqued the interest of scientists for their unique expression pattern. The MAGE genes can be classified into type I MAGEs that expressed in testis and other reproductive tissues while type II MAGEs that have broad expression in many tissues. Several MAGE gene families are expressed in embryonic tissues in almost all eukaryotes, which is essential for embryo development mainly during germ cell differentiation. The aim of this study was to analyze the promoter regions and regulatory elements (transcription factors and CpG islands) of MAGE genes encoding for embryonic development in cattle.

Results

The in silico analysis revealed the highest promoter prediction scores (1.0) for TSS were obtained for two gene sequences (MAGE B4-like and MAGE-L2) while the lowest promoter prediction scores (0.8) was obtained for MAGE B17-like. It also revealed that the best common motif, motif IV, bear a resemblance with three TF families including Zinc-finger family, SMAD family and E2A related factors. From thirteen identified TFs candidates, majority of them (11/13) were clustered to Zinc-finger family serving as transcriptionally activator role whereas three (SP1, SP3 and Znf423) of them as activator or repressor in response to physiological and pathological stimuli. On the other hand we revealed slightly rich CpG islands in the gene body and promoter regions of MAGE genes encoding for embryonic development in cattle.

Conclusion

This in silico analysis of gene promoter regions and regulatory elements in MAGE genes could be useful for understanding regulatory networks and gene expression patterns during embryo development in bovine.

Novel immune-related signature for risk stratification and prognosis in prostatic adenocarcinoma

A substantial proportion of prostatic adenocarcinoma (PRAD) patients experience biochemical failure (BCF) after radical prostatectomy (RP). The immune microenvironment plays a vital role in carcinogenesis and the development of PRAD. This study aimed to identify a novel immune-related gene (IRG)-based signature for risk stratification and prognosis of BCF in PRAD. Weighted gene coexpression network analysis was carried out to identify a BCF-related module in a discovery cohort of patients who underwent RP at the Massachusetts General Hospital. The median follow-up time was 70.32 months. Random forest and multivariate stepwise Cox regression analyses were used to identify an IRG-based signature from the specific module. Risk plot analyses, Kaplan-Meier curves, receiver operating characteristic curves, univariate and multivariate Cox regression analyses, stratified analysis, and Harrell's concordance index were used to assess the prognostic value and predictive accuracy of the IRG-based signature in the internal discovery cohort; The Cancer Genome Atlas database was used as a validation cohort. Tumor immune estimation resource database analysis and CIBERSORT algorithm were used to assess the immunophenotype of PRAD. A novel IRG-based signature was identified from the specific module. Five IRGs (BUB1B, NDN, NID1, COL4A6, and FLRT2) were verified as components of the risk signature. The IRG-based signature showed good prognostic value and predictive accuracy in both the discovery and validation cohorts. Infiltrations of various immune cells were significantly different between low-risk and high-risk groups in PRAD. We identified a novel IRG-based signature that could function as an index for assessing tumor immune status and risk stratification in PRAD.

Serum levels of ANOS1 serve as a diagnostic biomarker of gastric cancer: a prospective multicenter observational study

BACKGROUND

Development of high-performance serum biomarkers will likely improve treatment outcomes of patients with gastric cancer (GC). We previously identified the candidate serum markers, anosmin 1 (ANOS1), dihydropyrimidinase-like 3 (DPYSL3), and melanoma-associated antigen D2 (MAGE-D2) and evaluated their clinical significance through a single-center retrospective analysis. Here we conducted a prospective multicenter observational study aimed at validating the diagnostic performance of these potential markers.

METHODS

We analyzed serum levels before and after surgery of the three potential biomarkers in patients with GC and healthy volunteers. Quantification of serum and GC tissue levels was performed using an ELISA.

RESULTS

Area under the curve (AUC) values that discriminated patients with GC from healthy controls were - 0.7058, 0.6188, and 0.5031 for ANOS1, DPYSL3, and MAGED2, respectively. The sensitivity and specificity of the ANOS1 assay were 0.36 and 0.85, respectively. The AUC value of ANOS1 that discriminated patients with stage I GC from healthy controls was 0.7131. Serum ANOS1 levels were significantly elevated in patients with stage I GC compared with those of healthy controls (median 1179 ng/ml and 461 ng/ml, respectively, P < 0.0001) and decreased after resection of primary GC lesions (P < 0.0001). The combination of serum ANOS1 and DPYSL3 levels increased the AUC value that discriminated patients with GC from healthy controls. Serum levels of ANOS1 did not significantly correlate with those of carcinoembryonic antigen, carbohydrate antigen 19-9, or other markers of inflammation.

CONCLUSIONS

Serum levels of ANOS1 may serve as a useful diagnostic tool for managing GC.

An RNA guanine quadruplex regulated pathway to TRAIL-sensitization by DDX21

DDX21 is a newly discovered RNA G-quadruplex (rG4) binding protein with no known biological rG4 targets. In this study we used label-free proteomic MS/MS to identify 26 proteins that are expressed at significantly different levels in cells expressing an rG4-binding deficient DDX21 (M4). MS data are available via ProteomeXchange with identifier PXD013501. From this list we validate MAGED2 as a protein that is regulated by DDX21 through rG4 in its 5'-UTR. MAGED2 protein levels, but not mRNA levels, are reduced by half in cells expressing DDX21 M4. MAGED2 has a repressive effect on TRAIL-R2 expression that is relieved under these conditions, resulting in elevated TRAIL-R2 mRNA and protein in MCF-7 cells, rendering them sensitive to TRAIL-mediated apoptosis. Our work identifies the role of DDX21 in regulation at the translational level through biologically relevant rG4 and shows that MAGED2 protein levels are regulated, at least in part, by the potential to form rG4 in their 5'-UTRs.

Aberrantly enhanced melanoma-associated antigen (MAGE)-A3 expression facilitates cervical cancer cell proliferation and metastasis via actuating Wnt signaling pathway

BACKGROUND

The over-expression of melanoma-associated antigen (MAGE)-A3 in cervical cancer (CC) has been observed in our previous study, suggesting that it possibly take a vital role during the development and metastasis of CC. The present study aimed to investigate the biological function of MAGE-A3 in the progression of CC and explore how it executes its roles.

METHODS

The mRNA expression of MAGE-A3 in End1/E6E7 and CC cell lines (HeLa, SiHa and C33A) was measured by real-time quantitative reverse transcription PCR (qRT-PCR). Loss- and gain-of-function methods were used to assess the effect of MAGE-A3 on the proliferative, migratory and invasive abilities of HeLa and SiHa cells. Western blot was performed to measure the expression levels of proteins related to epithelial-mesenchymal transition (EMT) and proteins in the Wnt signaling pathway. In vivo tumorigenesis assay was conducted to evaluate the effect of MAGE-A3 on tumor growth.

RESULTS

MAGE-A3 expression was significantly up-regulated in CC cell lines (HeLa, SiHa and C33A) compared with that in End1/E6E7 cell line. Knockdown of MAGE-A3 could significantly suppress migration, invasion and proliferation in HeLa cells; whereas, overexpression of MAGE-A3 in SiHa cells presented the opposite results. Moreover, knockdown of MAGE-A3 presented a suppressive effect on the activation of EMT and Wnt signaling pathway in HeLa cells, whilst up-regulation of MAGE-A3 exhibited the opponent outcomes in SiHa cells. Through in vivo tumorigenesis assay, we further verified that MAGE-A3 acted as a facilitator in tumor growth.

CONCLUSIONS

MAGE-A3 is overexpressed in CC cells and possibly facilitates the viability and motility of CC cells via modulating EMT and Wnt signaling. This study implied that MAGE-A3 might be a potential therapeutic target as well as a prognosis predictor for patients with CC.

Immunomodulatory aspects in the progression and treatment of oral malignancy

Inflammation substantially affects the risk of oral malignancy. Pro-inflammatory cytokine, interferon (IFN)-γ, confers anti-tumor activity using several different mechanisms. Conversely, higher expression of interleukin (IL)-17 is associated with worse prognosis. Monocyte chemotactic protein (MCP)-1 correlates positively with poor long-term survival of head and neck squamous cell carcinoma (HNSCC) patients. IL-1α affects cancer associated fibroblasts and macrophages, and promote several malignant phenotypes including immune suppression. Some anti-inflammatory cytokines, including IL-10 and transforming growth factor (TGF)-β, relate to pro-tumoral activities. Among immune checkpoint modulators, programmed death (PD-)1 and PD-ligand (L)1 facilitate oral squamous cell carcinoma (OSCC) cell evasion from immune surveillance, and the expression status of these has a prognostic value. OSCCs contain tumor associated macrophages (TAMs) as major stromal cells of their tumor microenvironment. Among the two distinctive states, M2 macrophages support tumor invasion, metastasis and immune suppression. Crosstalk between TAMs and OSCC or cancer-associated fibroblasts (CAF) plays an important role in the progression of OSCC. Clinical trials with blocking antibodies against IL-1α or melanoma-associated antigens have been reported as therapeutic approaches against OSCCs. The most promising approach activating antitumor immunity is the blockade of PD-1/PD-L1 axis. Manipulating the polarization of pro-tumorigenic macrophages has been reported as a novel therapeutic approach.

Novel predication of protein biomarkers in interferon-gamma-stimulated breast cancer cells

OBJECTIVE

Proteomics is the large-scale study of localization, identification, structure, and function of the proteome. A proteome is the complete set of proteins expressed and modified by an organism under a specific set of environmental conditions. This study was undertaken to investigate the novel protein biomarkers that play a role in breast cancer under inflammatory condition.

METHODS

The two-dimensional gel electrophoresis (2-DE) was applied in the context of the breast cancer model system to investigate the effect of interferon-gamma (IFN-γ) on the differential protein expression in breast cancer-derived cell lines CAMA-1 and 3,4-methylenedioxyamphetamine (MDA)-MB-231. Whole cell lysates were prepared from IFN-γ-stimulated and non-stimulated CAMA-1 and MDA-MB-231 cells for 2-DE to obtain information for potential differential protein expression. Protein spots in the gels were visualized by silver staining and analyzed by Progenesis SameSpot. Gels were then scanned using the Epson image scanner with LabScan 6.0 software. The ExPASy tool was used to identify and quantify breast cancer cell membrane proteins expressed in response to IFN-γ.

RESULTS

In the present proteomics study, a series of differentially expressed proteins were analyzed in IFN-γ-stimulated CAMA-1 and MDA-MB-231 cells. While results obtained from this analysis can be used as preliminary data to identify differences between untreated and IFN-γ-treated samples, they were not used for further mass spectrometry analysis.

CONCLUSION

The data described and discussed here can be utilized for further data validation projects and could assist in the discovery of new breast cancer-related proteins and molecular pathways.

The potential immune-eliciting cancer testis antigens in colorectal cancer

The identification of cancer testis antigens (CTAs) has been an important finding in the search of potential targets for cancer immunotherapy. CTA is one of the subfamilies of the large tumor-associated antigens groups. It is aberrantly expressed in various types of human tumors but is absent in normal tissues except for the testis and placenta. This CTAs-restricted pattern of expression in human malignancies together with its potential immunogenic properties, has stirred the interest of many researchers to use CTAs as one of the ideal targets in cancer immunotherapy. To date, multiple studies have shown that CTAs-based vaccines can elicit clinical and immunological responses in different tumors, including colorectal cancer (CRC). This review details our current understanding of CTAs and CRC in regard to the expression and immunological responses as well as some of the critical hurdles in CTAs-based immunotherapy.

Epigenetics of pituitary tumors: Pathogenetic and therapeutic implications

Genetic mutations involving oncogenes or tumor suppressor genes are relatively uncommon in human sporadic pituitary tumors. Instead, increasing evidence has highlighted frequent epigenetic alterations including DNA methylation, histone modifications, and enhanced miRNA expression. This review covers some of this evidence as it illuminates mechanisms of tumorigenesis and highlights therapeutic opportunities.

Characterization of MAGEG2 with testis-specific expression in mice

Male germ cell development is a well-defined process occurring in numerous seminiferous tubules of the testis. Uncovering testicular novel genes related to intrinsic regulation of spermatogenesis is essential for the understanding of spermatogenesis. In the present study, we investigated mouse Mageg2, which belongs to a group of melanoma-associated antigens (MAGEs). Mageg2 is transcribed in the testis specifically, and its expression level is increased at the pachytene spermatocyte stage, indicating that Mageg2 is expressed predominantly in germ cells. We generated an antibody against mouse MAGEG2 for further characterization at the protein level. Immunoblot analysis suggested that MAGEG2 has specific testicular expression and the expression primarily occurred in pachytene spermatocytes. Proteomic analyses demonstrated that mouse MAGEG2 binded to testicular germ cell-specific serine/threonine-protein kinase 31 (STK31) and heat shock protein 9 (HSPA9). Direct binding with both interaction partners was confirmed by co-immunoprecipitation. We found that STK31 and HSPA9 bind MAGEG2 directly but not with each other. Interestingly, MAGEG2 reduced the kinase activity of STK31. Our study suggests that mouse MAGEG2 has at least two functions, including chaperone activity related to HSPA9 and regulation of pachytene spermatocyte-specific kinase, STK31. Altogether, our results provide the first information about MAGEG2 at the transcript and protein levels and suggest its potential molecular functions.

Gas‑filled ultrasound microbubbles enhance the immunoactivity of the HSP70‑MAGEA1 fusion protein against MAGEA1‑expressing tumours

Advanced malignant melanoma is characterized by rapid development, poor prognosis and insensitivity to chemoradiotherapy. Immunotherapy has become one of the primary clinical treatments for malignant melanomas. In recent decades, identifying specific tumour antigens and the enhanced immunoactivity of tumour vaccines has become critical for engineering successful tumour vaccines. As a widely used vaccine carrier, heat shock protein 70 (HSP70) clearly increases the immunogenicity of tumour antigens, such as melanoma-associated antigen A1 (MAGEA1). Based on previous studies, gas-filled ultrasound microbubbles (MBs) were engineered to carry an HSP70-MAGEA1 fusion protein (FP). Following subcutaneous injection around the lymphatic nodes the FP was directly released into the lymph nodes under ultrasonic imaging. The results indicated that the microbubbles enhanced the immunoactivity of FPs more effectively than HSP70-MAGEA1 fusion alone. Additionally, HSP70-MAGEA1 delivered via microbubbles clearly inhibited and delayed the growth of MAGEA1-expressing B16 melanomas in mice and improved the survival times of these animals compared with the fusion protein alone. The results of the present study demonstrated that controlled MBs enhance the immunoactivity of FPs and also highlights novel, potential vaccine carriers and a new strategy for engineering controllable tumour vaccine designs.

An In vivo study: Adjuvant activity of poly-n-vinyl-2-pyrrolidone-co-acrylic acid on immune responses against Melanoma synthetic peptide

Peptides have been studied as an important class of components in medicine to control many major diseases with vaccination. Polymers as adjuvants are capable of enhancing the vaccine potential against various diseases by improving the delivery of antigens, and they reduce the booster doses of vaccines. In brief, polymers are promising candidates for peptide-based vaccine delivery platforms. The purpose of the present study was to create a possible alternative approach in the treatment of malignant melanoma and/or to prevent metastasis of melanoma. The study was designed as both an experimental and an in vivo study. We prepared a complex and covalent conjugate of MAGE-3 121-134 (L-L-K-Y-R-A-R-E-P-V-T-K-A-E) T-cell epitope as a vaccine candidate for melanoma. These conjugates were able to generate an immune response in mice after a single immunization, without the help of any external adjuvant. The peptide-polymer complexes activated the immune system in the best way and formed the highest antigen specific immune response. These results indicate the adjuvant activity of Poly(N-vinyl-2- pyrrolidone-co-acrylic acid) [P(VP-co-AA)] and the potential use of P(VP-coAA)-peptide based vaccine prototypes for future melanoma cancer vaccine formulations.

Arginine (Di)methylated Human Leukocyte Antigen Class I Peptides Are Favorably Presented by HLA-B*07

Alterations in protein post-translational modification (PTM) are recognized hallmarks of diseases. These modifications potentially provide a unique source of disease-related human leukocyte antigen (HLA) class I-presented peptides that can elicit specific immune responses. While phosphorylated HLA peptides have already received attention, arginine methylated HLA class I peptide presentation has not been characterized in detail. In a human B-cell line we detected 149 HLA class I peptides harboring mono- and/or dimethylated arginine residues by mass spectrometry. A striking preference was observed in the presentation of arginine (di)methylated peptides for HLA-B*07 molecules, likely because the binding motifs of this allele resemble consensus sequences recognized by arginine methyl-transferases. Moreover, HLA-B*07-bound peptides preferentially harbored dimethylated groups at the P3 position, thus consecutively to the proline anchor residue. Such a proline-arginine sequence has been associated with the arginine methyl-transferases CARM1 and PRMT5. Making use of the specific neutral losses in fragmentation spectra, we found most of the peptides to be asymmetrically dimethylated, most likely by CARM1. These data expand our knowledge of the processing and presentation of arginine (di)methylated HLA class I peptides and demonstrate that these types of modified peptides can be presented for recognition by T-cells. HLA class I peptides with mono- and dimethylated arginine residues may therefore offer a novel target for immunotherapy.

Apoptosis transcriptional mechanism of feline infectious peritonitis virus infected cells

Apoptosis has been postulated to play an important role during feline infectious peritonitis virus (FIPV) infection; however, its mechanism is not well characterized. This study is focused on apoptosis and transcriptional profiling of FIPV-infected cells following in vitro infection of CRFK cells with FIPV 79-1146 WSU. Flow cytometry was used to determine mode of cell death in first 42 h post infection (hpi). FIPV infected cells underwent early apoptosis at 9 hpi (p < 0.05) followed by late apoptosis at 12 hpi (p < 0.05) and necrosis from 24 hpi (p < 0.05). Then, next generation sequencing was performed on 9 hpi and control uninfected cells by Illumina analyzer. An aggregate of 4546 genes (2229 down-regulated and 2317 up-regulated) from 17 cellular process, 11 molecular functions and 130 possible biological pathways were affected by FIPV. 131 genes from apoptosis cluster (80 down-regulated and 51 up-regulated) along with increase of apoptosis, p53, p38 MAPK, VEGF and chemokines/cytokines signaling pathways were probably involved in apoptosis process. Six of the de-regulated genes expression (RASSF1, BATF2, MAGEB16, PDCD5, TNFα and TRAF2) and TNFα protein concentration were analyzed by RT-qPCR and ELISA, respectively, at different time-points. Up-regulations of both pro-apoptotic (i.e. PDCD5) and anti-apoptotic (i.e. TRAF2) were detected from first hpi and continuing to deregulate during apoptosis process in the infected cells.

The Expression of Melanoma-Associated Antigen D2 Both in Surgically Resected and Serum Samples Serves as Clinically Relevant Biomarker of Gastric Cancer Progression

BACKGROUND

Sensitive biomarkers are necessary for risk classification of patients with gastric cancer (GC), especially ones at risk of distant metastases. Melanoma-associated antigen (MAGE)-D2 has been reported to play a role in the process of cell adhesion and metastatic potential of tumor cells in colorectal cancer. The purpose of this study was to identify a novel clinically relevant biomarker of GC.

METHODS

Expression analysis of MAGE-D2 was conducted in GC cell lines and clinical samples (surgical specimen and serum) in both mRNA and protein level. Correlations between MAGE-D2 expression status and clinicopathological factors were evaluated.

RESULTS

MAGE-D2 mRNA expression levels were similar between GC tissues and the corresponding normal adjacent tissues and were independent of GC differentiation or subtype. In 101 (45 %) of 225 patients, the expression level of MAGE-D2 mRNA was increased in GC tissues compared with the corresponding normal adjacent tissues. Increased expression of MAGE-D2 mRNA in GC tissues was associated with distant metastasis and early recurrence and was an independent prognostic factor (hazard ratio 2.27, 95 % confidence interval 1.39-3.74, P = 0.001). There was a stepwise increase in serum MAGE-D2 level going from healthy volunteers to patients with localized GC and then to those with extended GC (stage IV). Patients with preoperative serum MAGE-D2 levels >130 pg/ml had a more unfavorable prognosis than those with levels ≤130 pg/ml.

CONCLUSION

MAGE-D2 was associated with metastatic potential of GC and may represent a promising biomarker, both in gastric tissues and serum samples, for malignant behavior of GC.

Anticancer effects of adenovirus-mediated calreticulin and melanoma-associated antigen 3 expression on non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is highly prevalent and needs novel therapies. Melanoma-associated antigen 3 (MAGE-A3) is a lung cancer antigen and calreticulin (CALR) can modulate immune responses. Our previous study has shown that up-regulated MAGE-A3 and CALR expression inhibits the proliferation and invasion of glioma cells. In this study, we examined the effect of adenovirus (Ad)-mediated MAGE-A3 and/or CALR expression on the proliferation, invasion, and apoptosis of human NSCLC cells and on the vascular tube formation of human endothelial cells as well as on dendritic cell (DC) activation and induced CD8(+) cytotoxic T lymphocyte (CTL) activity in vitro. We found that low levels of CALR and MAGE-A3 were expressed by A549 cells, but only very low CALR was expressed by DC. Up-regulated CALR and MAGE-A3 expression by infection with Ad-CALR/MAGE-A3 significantly inhibited the proliferation and invasion, but promoted the apoptosis of A549 cells. Up-regulated CALR and MAGE-A3 expression significantly inhibited cyclin D1 expression and the AKT, ERK1/2 and NF-κB expression and phosphorylation in A549 cells. Up-regulated CALR expression inhibited the tube formation in human endothelial cells. Up-regulated CALR and MAGE-A3 expression synergistically enhanced classical DC activation by enhancing IL-12, but reducing IL-10 secretion. Furthermore, CTLs induced by up-regulated CALR and MAGE-A3 expressing DCs synergistically triggered A549 cell apoptosis, which was abrogated by treatment with anti-HLA I, but not anti-HLA II antibodies. Moreover, CTLs induced by CALR and MAGE-A3-expressing DCs had a higher frequency of A549-specific IFN-γ-secreting T cells. Our data indicated that up-regulated CALR and MAGE-A3 expression inhibited the carcinogenesis of NSCLC by modulating the AKT, ERK MAPK and NF-κB signaling and enhanced classical DC activation and MAGE-A3-specific CTL cytotoxicity. Therefore, our findings may provide new insights in understanding the role of CALR in modulating antigen-specific T cell immunity and may aid in the design of new therapies for NSCLC.

Aberrant expression of melanoma-associated antigen-D2 serves as a prognostic indicator of hepatocellular carcinoma outcome following curative hepatectomy

Hepatocellular carcinoma (HCC) is the most common cause of cancer-related mortality globally. Since the prognosis of advanced HCC patients is extremely poor, the development of novel molecular targets for diagnosis and therapy is urgently required. In the present study, the expression of the melanoma-associated antigen-D2 (MAGE-D2) gene was investigated to determine whether it affects the malignant phenotype of HCC and thus, may serve as a marker of prognosis. Therefore, the expression of MAGE-D2 mRNA and MAGE-D2 protein in nine HCC cell lines and 151 pairs of surgical tissues was analyzed. mRNA expression levels were analyzed using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry was used to compare the clinicopathological parameters of the tumors. A significant difference in the level of MAGE-D2 expression was observed between the normal liver and chronic hepatitis tissues, however, no significant differences were identified among the levels of the chronic hepatitis, cirrhosis and HCC tissues. The expression patterns of the MAGE-D2 protein were consistent with those of its mRNA. The expression levels of MAGE-D2 mRNA in 66 of 151 (44%) patients were higher in the HCC tissues compared with the corresponding non-cancerous tissues. In addition, the disease-specific survival time was significantly shorter for patients with higher levels of MAGE-D2 mRNA expression. Multivariate analysis identified increased expression of MAGE-D2 mRNA as an independent prognostic factor for disease-specific survival (hazard ratio, 2.65; 95% confidence interval, 1.43–4.98; P=0.002). However, increased expression levels of MAGE-D2 mRNA were not significantly associated with other clinicopathological parameters, including extrahepatic recurrence. These results indicated that MAGE-D2 mRNA affects tumor progression and may serve as a prognostic indicator following curative resection. In addition, MAGE-D2 may provide a target for the therapy of HCC.

Genome-wide analysis in human colorectal cancer cells reveals ischemia-mediated expression of motility genes via DNA hypomethylation

DNA hypomethylation is an important epigenetic modification found to occur in many different cancer types, leading to the upregulation of previously silenced genes and loss of genomic stability. We previously demonstrated that hypoxia and hypoglycaemia (ischemia), two common micro-environmental changes in solid tumours, decrease DNA methylation through the downregulation of DNMTs in human colorectal cancer cells. Here, we utilized a genome-wide cross-platform approach to identify genes hypomethylated and upregulated by ischemia. Following exposure to hypoxia or hypoglycaemia, methylated DNA from human colorectal cancer cells (HCT116) was immunoprecipitated and analysed with an Affymetrix promoter array. Additionally, RNA was isolated and analysed in parallel with an Affymetrix expression array. Ingenuity pathway analysis software revealed that a significant proportion of the genes hypomethylated and upregulated were involved in cellular movement, including PLAUR and CYR61. A Matrigel invasion assay revealed that indeed HCT116 cells grown in hypoxic or hypoglycaemic conditions have increased mobility capabilities. Confirmation of upregulated expression of cellular movement genes was performed with qPCR. The correlation between ischemia and metastasis is well established in cancer progression, but the molecular mechanisms responsible for this common observation have not been clearly identified. Our novel data suggests that hypoxia and hypoglycaemia may be driving changes in DNA methylation through downregulation of DNMTs. This is the first report to our knowledge that provides an explanation for the increased metastatic potential seen in ischemic cells; i.e. that ischemia could be driving DNA hypomethylation and increasing expression of cellular movement genes.

Centrosomal localisation of the cancer/testis (CT) antigens NY-ESO-1 and MAGE-C1 is regulated by proteasome activity in tumour cells

The Cancer/Testis (CT) antigen family of genes are transcriptionally repressed in most human tissues but are atypically re-expressed in many malignant tumour types. Their restricted expression profile makes CT antigens ideal targets for cancer immunotherapy. As little is known about whether CT antigens may be regulated by post-translational processing, we investigated the mechanisms governing degradation of NY-ESO-1 and MAGE-C1 in selected cancer cell lines. Inhibitors of proteasome-mediated degradation induced the partitioning of NY-ESO-1 and MAGE-C1 into a detergent insoluble fraction. Moreover, this treatment also resulted in increased localisation of NY-ESO-1 and MAGE-C1 at the centrosome. Despite their interaction, relocation of either NY-ESO-1 or MAGE-C1 to the centrosome could occur independently of each other. Using a series of truncated fragments, the regions corresponding to NY-ESO-1_91-150 and MAGE-C1_900-1116 were established as important for controlling both stability and localisation of these CT antigens. Our findings demonstrate that the steady state levels of NY-ESO-1 and MAGE-C1 are regulated by proteasomal degradation and that both behave as aggregation-prone proteins upon accumulation. With proteasome inhibitors being increasingly used as front-line treatment in cancer, these data raise issues about CT antigen processing for antigenic presentation and therefore immunogenicity in cancer patients.

Placental DNA methylation alterations associated with maternal tobacco smoking at the RUNX3 gene are also associated with gestational age

AIMS

The developmental origins of health and disease hypothesis states that later-life disease may be influenced by the quality of the in utero environment. Environmental toxicants can have detrimental effects on fetal development, potentially through effects on placental development and function. Maternal smoking during pregnancy is associated with low birth weight, preterm birth and other complications, and exposure to cigarette smoke in utero has been linked to gross pathologic and molecular changes to the placenta, including differential DNA methylation in placental tissue. The aim of this study was to investigate the relationship between maternal smoking during pregnancy, methylation changes in the placenta and gestational age.

MATERIALS & METHODS

We used Illumina(®)'s (CA, USA) Human Methylation27 BeadChip technology platform to investigate the methylation status of 21,551 autosomal, non-SNP-associated CpG loci in DNA extracted from 206 human placentas and examined loci whose variation in methylation was associated with maternal smoking during pregnancy.

RESULTS

We found that methylation patterns of a number of loci within the RUNX3 gene were significantly associated with smoking during pregnancy, and one of these loci was associated with decreased gestational age (p = 0.04).

CONCLUSION

Our findings, demonstrating maternal smoking-induced changes in DNA methylation at specific loci, suggest a mechanism by which in utero tobacco smoke exposure could exert its detrimental effects upon the health of the fetus.

Overexpression of melanoma-associated antigen D4 is an independent prognostic factor in squamous cell carcinoma of the esophagus

To pursue an urgently needed treatment target for esophageal cancer (EC), we investigated the function of the recently discovered melanoma-associated antigen (MAGE)-D4 in squamous cell EC. MAGE-D4 messenger RNA (mRNA) expression was analyzed in nine EC cell lines using quantitative reverse transcription polymerase chain reaction. In 65 surgical specimens of squamous cell EC with no prior neoadjuvant therapy, MAGE-D4 mRNA expression in EC tissues and corresponding normal tissues was analyzed and compared, and evaluated in terms of clinicopathological factors. In representative cases, MAGE-D4 protein distribution was analyzed immunohistochemically. The heterogeneity of MAGE-D4 mRNA expression was confirmed in EC cell lines by quantitative reverse transcription polymerase chain reaction. In surgical specimens, MAGE-D4 mRNA expression was significantly higher in EC tissues than in corresponding normal tissues (P < 0.001). Patients with the highest MAGE-D4 mRNA expression in EC tissues (top quartile, n = 17) had significantly shorter overall survival than patients with low expression (2-year survival: 44% and 73%, respectively, P = 0.006). Univariate analysis identified age (≥65 years), lymphatic involvement, and high MAGE-D4 mRNA expression as significant prognostic factors; high MAGE-D4 mRNA expression was also an independent prognostic factor in multivariable analysis (hazard ratio: 2.194; P = 0.039) and was significantly associated with Brinkman index (P = 0.008) and preoperative carcinoembryonic antigen level (P = 0.002). Immunohistochemical MAGE-D4b expression was consistent with MAGE-D4 mRNA profiling. Our results suggest that MAGE-D4 overexpression influences tumor progression, and MADE-D4 can be a prognostic marker and a potential molecular target in squamous cell EC.

Mechanism of pain generation for endometriosis-associated pelvic pain

PURPOSE

Endometriosis-associated pelvic pain appears due to persistent nociceptive stimulation, but the precise mechanisms remain poorly understood.

METHODS

A search was conducted to screen and select articles from PubMed.

MAIN RESULTS

Neurotrophins (NTs), a family of neuronal growth factors, are overexpressed in endometriosis and encompass NGF, BDNF and NT-3 and NT-4/5. NT receptors, TrkA and p75NTR, and NT receptor-interacting proteins, MAGE and NDN, were also expressed. NTs and their receptors play a role in the development and maintenance of neural tissues in non-neuronal cell types such as endometriosis. Nerve fibers contain unmyelinated sensory C, myelinated sensory Adelta and adrenergic nerve fibers that innervate abnormal cell growths. An increased release of proinflammatory cytokines from endometriotic lesions is responsible for the excessive sensory innervation and development of chronic pelvic pain.

CONCLUSIONS

The preponderance of the inflammatory milieu and subsequent hyperinnervation might be involved in the pathophysiology of pain generation in women with endometriosis.

Meta-analysis: preoperative transcatheter arterial chemoembolization does not improve prognosis of patients with resectable hepatocellular carcinoma

BACKGROUND

Long-term outcomes of partial liver resection of hepatocellular carcinoma (HCC) remain satisfactory due to high incidences of recurrence. This study was intended to see whether preoperative transcatheter arterial chemoembolization (TACE) reduces postoperative tumor recurrences and prolongs survival of patients with resectable HCC.

METHODS

A computerized literature search was performed to identify relevant articles. The quality of nonrandomized comparative studies (NRCTs) was assessed using the methodological index for nonrandomized studies (MINORS). Data synthesis was performed using Review Manager 5.0 software.

RESULTS

Twenty-one studies (4 randomized controlled trials and 17 NRCTs) with a total of 3,210 participants were suitable for analysis. There was no significant difference in disease-free and overall survival at 5-year (32.1% vs. 30.0% and 40.2% vs. 45.2%), and intra- and extra-hepatic recurrence (51.2% vs.53.6% and 12.9% vs.10.3%) between patients with and without preoperative TACE. Postoperative morbidity (28.9% vs. 26.8%) and in-hospital mortality (4.1% vs. 3.1%) were also similar between the two groups.

CONCLUSIONS

Preoperative TACE does not seem to improve prognosis and therefore it is prudent to recommend it as a preoperative routine procedure for resectable HCC.

DNA methylation of RUNX3 in papillary thyroid cancer

BACKGROUND/AIMS

The relationship between Runt-related transcription factor 3 (RUNX3) gene inactivation and various solid tumors has been reported; however, little information is available about RUNX3 in thyroid cancers.

METHODS

We evaluated the DNA methylation of RUNX3 in 13 papillary thyroid cancer tissues and four thyroid cancer cell lines. Additionally, using reverse transcriptase-polymerase chain reaction, we analyzed RUNX3 gene expression in several thyroid cancer cell lines after treating with the demethylating agent 5-aza-2'-deoxycytidine (DAC).

RESULTS

RUNX3 was hypermethylated in many thyroid cancer cell lines and in 10 of the 12 papillary thyroid cancer tissues. Treatment with DAC increased the expression of RUNX3 in some thyroid cancer cell lines.

CONCLUSIONS

We suggest that RUNX3 is associated with thyroid carcinogenesis, and RUNX3 methylation is a potentially useful diagnostic marker for papillary thyroid cancer.

Hepatitis viruses infection and risk of intrahepatic cholangiocarcinoma: evidence from a meta-analysis

Background

Studies investigating the association between Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections and intrahepatic cholangiocarcinoma (ICC) have reported inconsistent findings. We conducted a meta-analysis of epidemiological studies to explore this relationship.

Methods

A comprehensive search was conducted to identify the eligible studies of hepatitis infections and ICC risk up to September 2011. Summary odds ratios (OR) with their 95% confidence intervals (95% CI) were calculated with random-effects models using Review Manager version 5.0.

Results

Thirteen case–control studies and 3 cohort studies were included in the final analysis. The combined risk estimate of all studies showed statistically significant increased risk of ICC incidence with HBV and HCV infection (OR = 3.17, 95% CI, 1.88-5.34, and OR = 3.42, 95% CI, 1.96-5.99, respectively). For case–control studies alone, the combined OR of infection with HBV and HCV were 2.86 (95% CI, 1.60-5.11) and 3.63 (95% CI, 1.86-7.05), respectively, and for cohort studies alone, the OR of HBV and HCV infection were 5.39 (95% CI, 2.34-12.44) and 2.60 (95% CI, 1.36-4.97), respectively.

Conclusions

This study suggests that both HBV and HCV infection are associated with an increased risk of ICC.

Differential gene expression profiling of primary cutaneous melanoma and sentinel lymph node metastases

Limited understanding of molecular mechanisms of metastasis in melanoma contributes to the absence of effective treatments. Increased knowledge of alterations in genes that underpin critical molecular events that lead to metastasis is essential. We have investigated the gene expression profiles of primary melanomas and melanoma metastases in sentinel lymph nodes. A total of 19 samples (10 primary melanomas and 9 sentinel lymph node metastases) were evaluated. Melanoma cells were dissected from tissue blocks. Total mRNA was isolated, amplified, and labeled using an Ambion Recover All Total Nucleic Acid Isolation kit, Nu-GEN WT-Ovation formalin-fixed, paraffin-embedded RNA Amplification System, and FL-Ovation cDNA Biotin Module V2, respectively. Samples were hybridized to the Affymetrix Gene Chip Human U133 Plus 2.0 Array. Data were analyzed using Partek Genomics Suite Version 6.4. Genes selected showed ≥2-fold difference in expression and P<5.00E-2. Validation studies used standard immunohistochemical assays. Hierarchical clustering disclosed two distinct groups: 10 primary melanomas and 9 sentinel lymph node metastases. Gene expression analysis identified 576 genes that showed significant differential expression. Most differences reflected decreased gene expression in metastases relative to primaries. Reduced gene expression in primaries was less frequent and less dramatic. Genes significantly increased or decreased in sentinel lymph node metastases were active in cell adhesion/structural integrity, tumor suppression, cell cycle regulation, and apoptosis. Validation studies indicate that MAGEC1 (melanoma antigen family C1) and FCRL1 (Fc receptor-like 1) are involved in melanoma progression. There are striking differential gene expression patterns between primary and nodally metastatic melanomas. Similar findings were seen with autologous paired primary melanomas and sentinel lymph node metastases, supporting involvement of these gene alterations in evolution of metastases. With further study, it may be possible to determine the exact sequence of molecular events that underlie melanoma metastases.

Adenovirus-mediated delivery of CALR and MAGE-A3 inhibits invasion and angiogenesis of glioblastoma cell line U87

Background

The management of patients with glioblastoma multiforme is difficult. Poor results have led to a search for novel therapeutic approaches. Gene therapy that could be both anti-invasive and antiangiogenic would be ideal. In this study, we constructed the recombinant adenoviral vector Ad-CALR/MAGE-A3 and evaluated its antitumor effects on glioblastoma in vitro and in vivo.

Methods

In this study, CALR and MAGE-A3 genes were delivered to the glioblastoma cell line U87, using adenovirus (Ad-CALR/MAGE-A3). U87 glioblastoma cells were transfected with Ad-green fluorescent protein to identify the multiplicity of infection. The expressions of CALR and MAGE-A3 were detected by PCR and Western blot. Cell proliferation was measured by MTT assay. Cell apoptosis was assessed by Annexin-V FITC/PI double staining flow cytometry. The invasive potential of U87 cells was determined by Matrigel invasion assay. Tube formation assay was used to detect the effects on angiogenesis of human umbilical vein endothelial cells. Protein expressions of PI3K/AKT, Erk1/2 and MMP-2/-9 in transfected cells were detected by Western blot. In vivo, the effects of Ad-CALR/MAGE-A3 on tumor growth and angiogenesis of U87 glioblastoma xenografts in nude mice were investigated.

Results

The expressions of CALR and MAGE-A3 in U87 cells resulted in the suppression of cell proliferation and invasion properties, and induced cell apoptosis. The Erk MAPK, PI3K/AKT pathways and expressions of MMP-2/-9 were inhibited in Ad-CALR/MAGE-A3-transfected cells. Outcomes of the tube formation assay confirmed the antiangiogenic effect of CALR. Moreover, in the in vivo model of glioblastoma, intratumoral injection of Ad-CALR/MAGE-A3 suppressed tumor growth and angiogenesis.

Conclusion

Although Ad-CALR/MAGE-A3 and Ad-CALR demonstrated antiangiogenic effects on U87 cells, the repression of invasion was significant only in Ad-CALR/MAGE-A3-treated cells. To our knowledge, this is the first description of a role for combined CALR and MAGE-A3 in the anti-invasion and antiangiogenesis of U87.

miR-34a confers chemosensitivity through modulation of MAGE-A and p53 in medulloblastoma

Recent studies have established miR-34a as a key effector of the p53 signaling pathway and have implicated its role in multiple cancer types. Here, we establish that miR-34a induces apoptosis, G2 arrest, and senescence in medulloblastoma and renders these cells more sensitive to chemotherapeutic agents. These effects are mediated in part by the direct post-transcriptional repression of the oncogenic MAGE-A gene family. We demonstrate that miR-34a directly targets the 3' untranslated regions of MAGE-A genes and decreases MAGE-A protein levels. This decrease in MAGE-A results in a concomitant increase in p53 and its associated transcriptional targets, p21/WAF1/CIP1 and, importantly, miR-34a. This establishes a positive feedback mechanism where miR-34a is not only induced by p53 but increases p53 mRNA and protein levels through the modulation of MAGE-A genes. Additionally, the forced expression of miR-34a or the knockdown of MAGE-A genes by small interfering RNA similarly sensitizes medulloblastoma cells to several classes of chemotherapeutic agents, including mitomycin C and cisplatin. Finally, the analysis of mRNA and micro-RNA transcriptional profiles of a series of primary medulloblastomas identifies a subset of tumors with low miR-34a expression and correspondingly high MAGE-A expression, suggesting the coordinate regulation of these genes. Our work establishes a role for miR-34a in modulating responsiveness to chemotherapy in medulloblastoma and presents a novel positive feedback mechanism involving miR-34a and p53, via direct targeting of MAGE-A.

Differential gene expression profile of MAGE family in taiwanese patients with colorectal cancer

BACKGROUND

The melanoma-associated antigen (MAGE) gene family consists of different expression patterns in various tumor types. They are considered tumor-specific antigens and are ideal targets for cancer immunotherapy. The purpose of this study is to identify the expression profiles of the MAGE family genes in Taiwanese colorectal cancer patients.

METHODS

In this study, a well-constructed chip array platform was used to analyze the expression of the MAGE family genes of 100 colorectal cancer tissues. Statistical analysis of the experimental results and patients' clinical manifestations were also conducted.

RESULTS

The results showed MAGE-A2 (87%), -A7 (83%), -A8 (75%), -A12 (71%), -B2 (75%), -B3 (79%), -D2 (75%), -F1 (79%), and -H1 (70%) were significantly overexpressed genes in colorectal cancer tissues. MAGE-A2 was the most highly overexpressed gene among the MAGE family. MAGE-B3 gene expression is statistically correlated with tumor size, lymph node, and UICC stage. In addition, the overexpression of MAGE-D2 and -H1 genes are statistically correlated to the tumor size and depth, respectively (P < 0.05).

CONCLUSIONS

This is the first comprehensive report to clarify the differential expression profile of whole MAGE family in CRCs, and it might provide some crucial information about the carcinogenesis and progression in Taiwanese patients with CRC.

Dlxin-1, a MAGE family protein, induces accelerated neurite outgrowth and cell survival by enhanced and early activation of MEK and Akt signalling pathways in PC12 cells

Dlxin-1 (also known as NRAGE or MAGED1) is a member of Type II melanoma-associated antigen (MAGE) family of proteins characterized by presence of a unique region of about 200 amino acids known as the MAGE homology domain (MHD). Dlxin-1 is associated with a large number of diverse cellular functions ranging from transcriptional regulation, cell cycle progression and differentiation to developmental apoptosis. While there are numerous studies reporting the role of NRAGE in facilitating cell death by interaction with p75NTR, we found varied effects of Dlxin-1 over-expression on PC12 cells grown in presence of NGF. These include induction of increased cell survival in presence of NGF and accelerated neuronal differentiation. We here categorically demonstrate that the effects on neuritogenesis are promoted through interactions of Dlxin-1 with the neurotrophin receptor TrkA. Further, using pharmacological inhibitors to specific pathways, we delineate the effects on enhanced neuritogenesis to the early and sustained activation of MEK pathway whereas the effects on cell survival to the early activation of Akt pathway. Next, we demonstrate a physical interaction of necdin with Dlxin-1 in PC12 cells. Our results establish that Dlxin-1 is an enhancer of neuronal differentiation and suggests that its possible interaction with NGF and necdin is critical in mediating pathways involved in neuronal survival and differentiation. Further in-depth analyses of the activation of various signalling pathways mediated through interaction with Dlxin-1 may provide valuable insight on the mechanisms that govern decisions regarding neuronal survival, growth, differentiation or apoptosis.

Mapping of NRAGE domains reveals clues to cell viability in BMP signaling

Bone morphogenetic signaling (BMP) is a key pathway during neurogenesis and depends on many downstream intermediators to carry out its signaling. One such signaling pathway utilizes neurotrophin receptor-interacting MAGE protein (NRAGE), a member of the melanoma-associated antigen (MAGE) family, to upregulate p38 mitogen activated protein kinase (p38(MAPK)) in response to cellular stress and activate caspases which are critical in leading cells to death. NRAGE consists of two conserved MAGE homology domains separated by a unique hexapeptide repeat domain. Although we have previously implicated NRAGE in inducing apoptosis in neural progenitors and P19 cells, a model system for neural progenitors, its domains have yet to be explored in determining which one may be responsible for setting up the signaling for apoptosis. Here, we overexpressed a series of deletion mutations in P19 cells to show that only those with at least half of the repeat domain, activated p38(MAPK) and underwent apoptosis offering intriguing incite into NRAGE's contribution in BMP apoptotic signaling.

Impact of MAGE-A antigens on taxane response in oral squamous cell carcinoma

MAGE-A antigens are a subgroup of cancer/testis antigens that are exclusively expressed in malignant cells. Only scarce information on the function of MAGE-A antigens is available. There is some evidence that they may influence the response to chemotherapeutic drugs. This study aimed to evaluate the impact of the MAGE-A antigen subgroups MAGE-A2, -A3, -A4 and -A6 on oral squamous cell carcinoma cell lines treated with docetaxel and paclitaxel. Five oral squamous cell carcinoma cell lines were characterized for their quantitative expression of MAGE-A2, -A3, -A4 and -A6. The cell lines were treated with concentrations ranging from 0.025 to 0.8 μM of docetaxel and paclitaxel. The amount of viable cells after 24 and 48 h was measured. The measurements were statistically correlated with MAGE-A expression. All cell lines responded to docetaxel and paclitaxel. One cell line showed a statistically significant weaker response to the taxane treatment. This cell line was the only one that expressed MAGE-A4. MAGE-A4 has a statistically significant impact on the tumour response to docetaxel and paclitaxel in oral squamous cell carcinoma. This may influence treatment options and the course of the disease. Therefore, patients should be evaluated for MAGE-A4 expression before treatment with taxanes.

Detection of circulating lymphoma cells in patients with non-Hodgkin lymphoma using MAGE-A3 gene expression in peripheral blood

BACKGROUND/AIMS

Lymphoma-specific gene expression in peripheral blood reflects the presence of circulating lymphoma cells (CLCs). MAGE-A3 is widely expressed in solid tumors and is a potent candidate for immunotherapy. To determine whether MAGE-A3 expression would be a useful marker for CLCs in non-Hodgkin lymphoma (NHL), we assessed MAGE-A3 mRNA expression in the peripheral blood of NHL patients and controls.

METHODS

We measured MAGE-A3 gene expression in ten lymphoma cell lines (Farage, RL, SU-DHL, Toledo, WSU-NHL, BJA-B, Daudi, Raji, Granta-519 and Jurkat) using nested RT-PCR, and determined detection sensitivity using mixtures of MAGE-A3-positive and -negative cells over a range of 1/10(6) to 10(6)/10(6) cells. MAGE-A3 expression was determined in buffy coat samples of 40 controls and 95 NHL patients prior to treatment. Clinical characteristics (e.g., cell lineage) and international prognostic indices, including age, performance, LDH, stage and extra-nodal involvement, were evaluated and related to MAGE-A3 expression. Hazard ratios, reflecting risk for overall survival and progression-free survival, were also evaluated. Follow-up MAGE-A3 expression was evaluated at two time points: after 3-4 cycles of chemotherapy (80 patients) and after 6-8 cycles of chemotherapy (74 patients).

RESULTS

MAGE-A3 mRNA was detected in four lymphoma cell lines - RL, Farage, Toledo and Raji - and was present in 45 of 95 (47.3%) patients with NHL, but in none of the 40 controls. The detection sensitivity was 1 in 1000 cells. MAGE-A3 expression prior to treatment was not associated with clinical features or patient survival. During follow-up, only six patients (7.5%) were positive for MAGE-A3 after 3-4 cycles of chemotherapy and three (4.1%) were positive after 6-8 cycles.

CONCLUSIONS

The results showed that MAGE-A3 gene expression was frequent in NHL patients and decreased after effective chemotherapy, suggesting that MAGE-A3 can be used as a tumor marker for CLCs in patients with NHL. However, MAGE-A3 expression showed no prognostic value in this group of patients.

Necdin: a multi functional protein with potential tumor suppressor role?

Necdin (NDN), a member of the melanoma-associated antigen (MAGE) family of proteins was first identified in mouse stem cells of embryonal carcinoma origin induced to differentiate by treatment with retinoic acid. The human gene maps to chromosome 15q11. This imprinted region is implicated in the pathogenesis of Prader-Willi syndrome (PWS), a neurodevelopmental disorder, where NDN is one of multiple genes silenced by deletion, maternal uniparental disomy or translocation. Due to this association, much interest has focused on the role of NDN in neuronal development and differentiation. However, a considerable number of studies have identified additional functions of NDN. Taken together these studies suggest a pleiotropic protein with diverse functions some of which may be relevant to tumorigenesis. Downregulation of NDN occurs in carcinoma cell lines and primary tumors, suggesting a tumor suppressor role. Our working hypothesis is that NDN is a worthy candidate for further studies with regard to a potential tumor suppressor role. In this article we outline the considerable evidence supporting the hypothesis that NDN has multiple functions, some of which indicate that it could be a tumor suppressor. The roles of NDN in key processes such as interaction with p53 and E2F-1, hematopoietic stem cell quiescence, transcriptional repression, angiogenesis, differentiation and interaction with the polycomb group gene BMI1 are discussed. Confirmation of NDN as a tumor suppressor may have implications for monitoring of PWS patients and could present a novel cancer therapeutic target.

Necdin restricts proliferation of hematopoietic stem cells during hematopoietic regeneration

Hematopoietic stem cell (HSC) proliferation is tightly regulated by a poorly understood complex of positive and negative cell-cycle regulatory mechanisms. Necdin (Ndn) is an evolutionally conserved multifunctional protein that has been implicated in cell-cycle regulation of neuronal cells. Here, we provide evidence that necdin plays an important role in restricting excessive HSC proliferation during hematopoietic regeneration. We identify Ndn as being preferentially expressed in the HSC population on the basis of gene expression profiling and demonstrate that mice deficient in Ndn show accelerated recovery of the hematopoietic system after myelosuppressive injury, whereas no overt abnormality is seen in steady-state hematopoiesis. In parallel, after myelosuppression, Ndn-deficient mice exhibit an enhanced number of proliferating HSCs. Based on these findings, we propose that necdin functions in a negative feedback loop that prevents excessive proliferation of HSCs during hematopoietic regeneration. These data suggest that the inhibition of necdin after clinical myelosuppressive treatment (eg, chemotherapy, HSC transplantation) may provide therapeutic benefits by accelerating hematologic recovery.

Differential 14-3-3 affinity capture reveals new downstream targets of phosphatidylinositol 3-kinase signaling

We devised a strategy of 14-3-3 affinity capture and release, isotope differential (d₀/d₄) dimethyl labeling of tryptic digests, and phosphopeptide characterization to identify novel targets of insulin/IGF1/phosphatidylinositol 3-kinase signaling. Notably four known insulin-regulated proteins (PFK-2, PRAS40, AS160, and MYO1C) had high d₀/d₄ values meaning that they were more highly represented among 14-3-3-binding proteins from insulin-stimulated than unstimulated cells. Among novel candidates, insulin receptor substrate 2, the proapoptotic CCDC6, E3 ubiquitin ligase ZNRF2, and signaling adapter SASH1 were confirmed to bind to 14-3-3s in response to IGF1/phosphatidylinositol 3-kinase signaling. Insulin receptor substrate 2, ZNRF2, and SASH1 were also regulated by phorbol ester via p90RSK, whereas CCDC6 and PRAS40 were not. In contrast, the actin-associated protein vasodilator-stimulated phosphoprotein and lipolysis-stimulated lipoprotein receptor, which had low d₀/d₄ scores, bound 14-3-3s irrespective of IGF1 and phorbol ester. Phosphorylated Ser¹⁹ of ZNRF2 (RTRAYpS¹⁹GS), phospho-Ser⁹⁰ of SASH1 (RKRRVpS⁹⁰QD), and phospho- Ser⁴⁹³ of lipolysis-stimulated lipoprotein receptor (RPRARpS⁴⁹³LD) provide one of the 14-3-3-binding sites on each of these proteins. Differential 14-3-3 capture provides a powerful approach to defining downstream regulatory mechanisms for specific signaling pathways.

EBNA3C can modulate the activities of the transcription factor Necdin in association with metastasis suppressor protein Nm23-H1

Previous studies have demonstrated the interaction between the Epstein-Barr virus (EBV) nuclear antigen 3C (EBNA3C) and the metastatic suppressor Nm23-H1 both in vitro and in vivo (C. Subramanian, M. A. Cotter II, and E. S. Robertson, Nat. Med. 7:350-355, 2001). Importantly EBNA3C can reverse the ability of Nm23-H1 to suppress migration of human cells in vitro. EBNA3C contributes to EBV-associated human cancers by regulating transcription of a number of cellular and viral promoters as well as targeting and altering the transcription activities of the metastasis suppressor Nm23-H1. Furthermore, Necdin is a cellular protein which is highly induced in terminally differentiated cells; it contributes to the regulation of cell growth and is also known to interact with viral oncoproteins. In this report, we show that Nm23-H1 and EBNA3C can modulate the biological functions of Necdin in the context of EBV infection and transformation. The levels of Necdin were consistently lower in EBV-positive cells, and EBNA3C could change the subcellular localization of Necdin as well as rescue cells from the antiangiogenic and antiproliferative effects mediated by Necdin. We also show that Necdin directly interacts with Nm23-H1, resulting in modulation of the biochemical function of Nm23-H1 as well as the biological function of Necdin. Both EBNA3C and Nm23-H1 were able to rescue not only Necdin-mediated transcriptional repression of the downstream vascular endothelial growth factor promoter but also Necdin-mediated growth suppression and antiangiogenic effects on cancer cells. The majority of this response was mediated through amino acid residues 191 to 222 of Necdin, which are also known to be important for nuclear matrix targeting. These studies suggest a role for Necdin in the regulation of downstream cellular targets in a hypoxic environment in virus-associated human cancers.

Identification of genomic alterations associated with the aggressiveness of pancreatic cancer using an ultra-high-resolution CGH array

BACKGROUND

Genomic alterations present in pancreatic adenocarcinoma have been described only partially. In addition, the relations between these alterations and the aggressiveness of the phenotype remain unknown.

METHODS

Genomic DNA and total RNA from 5 pancreatic cell lines, of which 2 have an aggressive phenotype and are gemcitabine-resistant (Mia-Paca2 and Panc-1), and 3 less aggressive and gemcitabine-sensitive (Capan-1, Capan-2 and BxPC3), have been purified. DNA abnormalities have been analyzed using an ultra-high-resolution CGH array and mRNA expression was studied with an Affymetrix GeneChip expression array.

RESULTS

We identified 573 amplified and 30 deleted genes common to all 5 cell lines. Some of them have already been described, whereas other genes, implicated in signal transduction, apoptosis, cell cycle or cell migration, are described for the first time as being related to this cancer. Comparison of genomic abnormalities between the 2 most aggressive and the 3 less aggressive cell lines led to the identification of 368 genes specifically amplified in the aggressive cell lines. However, no specific gene deletion seems to be associated with the aggressive phenotype.

CONCLUSION

Using a high-resolution approach, we could precisely describe the genomic alterations associated with pancreatic adenocarcinoma and determine those associated with an aggressive phenotype.

Epigenetic control in pituitary tumors

Epigenetically-mediated gene dysregulation is a common feature associated with human pituitary tumorigenesis. The mechanisms leading to these changes, however, remain largely unknown. In this review, we examine changes responsible for DNA and histone modifications as independent, butpotentially interrlated modes of communication effecting chromatin remodeling. The dynamic properties of the enzymes involved in these reactions is highlighted. We use the fibroblast growth factor receptor 2 (FGFR2) as a model through which the p53-regulating melanoma-associated antigen (MAGE) system is governing in pituitary cells. The pathogenetic and potential therapeutic implications are discussed.

MAGE-B2 autoantibody: a new biomarker for pediatric systemic lupus erythematosus

OBJECTIVE

Melanoma-associated antigen gene B2 (MAGE-B2) encodes an embryonic antigen normally silenced after birth except in testis and placenta. We identified the MAGE-B2 gene and autoantibodies in pediatric patients with systemic lupus erythematosus (SLE) glomerulonephritis. We investigated the prevalence of MAGE-B2 autoantibodies in association with active SLE, to determine a pathogenetic role of MAGE-B2 protein through its distribution in cells and tissues.

METHODS

A cross-sectional study analyzed the frequency of MAGE-B2 autoantibodies in 40 patients with pediatric SLE, 23 adult controls, and 16 patients with pediatric juvenile rheumatoid arthritis (JRA) using Western blots containing recombinant MAGE-B2. SLE Disease Activity Index 2000 (SLEDAI-2K) and British Isles Lupus Assessment Group (BILAG) index measured SLE disease activity. Tissue distribution of MAGE-B2 protein was assessed by immunohistochemistry, immunofluorescence, and Western blots.

RESULTS

Seventeen (43%) of 40 pediatric SLE patients had MAGE-B2 autoantibodies as compared to 0 of 16 JRA patients and 2 of 23 adult controls. SLE disease activity was significantly higher in MAGE-B2 autoantibody-positive versus autoantibody-negative patients (SLEDAI-2K, mean 10.9 vs 5.2, p = 0.013; BILAG, mean 15.3 vs 6.3, p = 0.023). Active nephritis was more prevalent (60% vs 24%) in MAGE-B2 autoantibody-positive than autoantibody-negative SLE patients. MAGE-B2 protein was visualized in SLE kidney proximal convoluted tubules and in tumor epithelial cells, but not in lymphoblastoid cells.

CONCLUSION

MAGE-B2 autoantibody appears to be a clinically relevant biomarker for pediatric SLE disease activity and nephritis.

Fibroblast growth factor 2 and estrogen control the balance of histone 3 modifications targeting MAGE-A3 in pituitary neoplasia

PURPOSE

Four members of the fibroblast growth factor receptor (FGFR) family transduce signals of a diverse group of FGF ligands. The FGFR2-IIIb isoform is abundantly present in the normal pituitary gland with contrasting down-regulation in neoplastic pituitary cells. cDNA profiling identified the cancer-testis antigen melanoma-associated antigen A3 (MAGE-A3) as a putative target negatively regulated by FGFR2.

EXPERIMENTAL DESIGN

Comparisons were made between normal and neoplastic human and mouse pituitary cells. Gene expression was examined by reverse transcription-PCR, DNA methylation was determined by methylation-specific PCR and combined bisulfite restriction analysis, and histone modification marks were identified by chromatin immunoprecipitation.

RESULTS

Normal human pituitary tissue that expresses FGFR2-IIIb does not express MAGE-A3; in contrast, pituitary tumors that are FGFR2 negative show abundant MAGE-A3 mRNA expression. MAGE-A3 expression correlates with the presence and extent of DNA promoter methylation; more frequent and higher-degree methylation is present in the normal gland compared with pituitary tumors. Conversely, pituitary tumors are hypomethylated, particularly in females where MAGE-A3 expression is nearly thrice higher than in males. Estradiol treatment induces MAGE-A3 through enhanced histone 3 acetylation and diminished methylation. The effects of estradiol are directly opposed by FGF7/FGFR2-IIIb. Down-regulation of MAGE-A3 results in p53 transcriptional induction, also through reciprocal histone acetylation and methylation modifications.

CONCLUSIONS

These findings highlight MAGE-A3 as a target of FGFR2-IIIb and estrogen action and provide evidence for a common histone-modifying network in the control of the balance between opposing signals.

Epigenetic dysregulation in thyroid neoplasia

Gain-of-function mutations in oncogenes have aided our understanding of the molecular mechanisms of thyroid carcinogenesis. Mutations or deletions cause inactivation of tumor suppressor genes in thyroid carcinomas. However, recent advances have disclosed the significance of epigenetic events in the development and progression of human tumorigenesis. Indeed, various tumor-suppressor genes and thyroid hormone-related genes are epigenetically silenced in thyroid tumors. This article reviews the evidence for epigenetic gene dysregulation in follicular cell-derived thyroid carcinomas including papillary thyroid carcinoma, follicular thyroid carcinoma, and undifferentiated thyroid carcinoma. The authors also discuss future applications of epigenetics as ancillary diagnostic tools and in the design of targeted therapies for thyroid cancer.