Large scale identification of human hepatocellular carcinoma-associated antigens by autoantibodies

AGO2-RIP-Seq reveals miR-34/miR-449 cluster targetome in sinonasal cancers

Sinonasal tumours are heterogeneous malignancies, presenting different histological features and clinical behaviour. Many studies emphasize the role of specific miRNA in the development and progression of cancer, and their expression profiles could be used as prognostic biomarkers to predict the survival. Recently, using the next-generation sequencing (NGS)-based miRNome analysis the miR-34/miR-449 cluster was identified as miRNA superfamily involved in the pathogenesis of sinonasal cancers (SNCs). In the present study, we established an Argonaute-2 (AGO2): mRNA immunoprecipitation followed by high-throughput sequencing to analyse the regulatory role of miR-34/miR-449 in SNCs. Using this approach, we identified direct target genes (targetome), which were involved in regulation of RNA-DNA metabolic, transcript and epigenetic processes. In particular, the STK3, C9orf78 and STRN3 genes were the direct targets of both miR-34c and miR-449a, and their regulation are predictive of tumour progression. This study provides the first evidence that miR-34/miR-449 and their targets are deregulated in SNCs and could be proposed as valuable prognostic biomarkers.

Autoantibodies to PAX5, PTCH1, and GNA11 as Serological Biomarkers in the Detection of Hepatocellular Carcinoma in Hispanic Americans

Studies have demonstrated that autoantibodies to tumor-associated antigens (TAAs) may be used as efficient biomarkers with low-cost and highly sensitive characteristics. In this study, an enzyme-linked immunosorbent assay (ELISA) was conducted to analyze autoantibodies to paired box protein Pax-5 (PAX5), protein patched homolog 1 (PTCH1), and guanine nucleotide-binding protein subunit alpha-11 (GNA11) in sera from Hispanic Americans including hepatocellular carcinoma (HCC) patients, patients with liver cirrhosis (LC), patients with chronic hepatitis (CH), as well as normal controls. Meanwhile, 33 serial sera from eight HCC patients before and after diagnosis were used to explore the potential of these three autoantibodies as early biomarkers. In addition, an independent non-Hispanic cohort was used to evaluate the specificity of these three autoantibodies. In the Hispanic cohort, at the 95.0% specificity for healthy controls, 52.0%, 44.0%, and 44.0% of HCC patients showed significantly elevated levels of autoantibodies to PAX5, PTCH1, and GNA11, respectively. Among patients with LC, the frequencies for autoantibodies to PAX5, PTCH1, and GNA11 were 32.1%, 35.7%, and 25.0%, respectively. The area under the ROC curves (AUCs) of autoantibodies to PAX5, PTCH1, and GNA11 for identifying HCC from healthy controls were 0.908, 0.924, and 0.913, respectively. When these three autoantibodies were combined as a panel, the sensitivity could be improved to 68%. The prevalence of PAX5, PTCH1, and GNA11 autoantibodies has already occurred in 62.5%, 62.5%, or 75.0% of patients before clinical diagnosis, respectively. In the non-Hispanic cohort, autoantibodies to PTCH1 showed no significant difference; however, autoantibodies to PAX5, PTCH1, and GNA11 showed potential value as biomarkers for early detection of HCC in the Hispanic population and they may monitor the transition of patients with high-risk (LC, CH) to HCC. Using a panel of the three anti-TAA autoantibodies may enhance the detection of HCC.

Immune checkpoints expression patterns in early-stage triple-negative breast cancer predict prognosis and remodel the tumor immune microenvironment

Background

Currently, targeting immune checkpoint molecules holds great promise for triple-negative breast cancer (TNBC). However, the expression landscape of immune checkpoint genes (ICGs) in TNBC remains largely unknown.

Method

Herein, we systematically investigated the ICGs expression patterns in 422 TNBC samples. We evaluated the ICGs molecular typing based on the ICGs expression profile and explored the associations between ICGs molecular subtypes and tumor immune characteristics, clinical significance, and response to immune checkpoint inhibitors (ICIs).

Results

Two ICGs clusters and two ICGs-related gene clusters were determined, which were involved in different survival outcomes, biological roles and infiltration levels of immune cells. We established a quantification system ICGs riskscore (named IRS) to assess the ICGs expression patterns for individuals. TNBC patients with lower IRS were characterized by increased immune cell infiltration, favorable clinical outcomes and high sensitivity to ICIs therapy. We also developed a nomogram model combining clinicopathological variables to predict overall survival in TNBC. Genomic feature analysis revealed that high IRS group presented an increased tumor mutation burden compared with the low IRS group.

Conclusion

Collectively, dissecting the ICGs expression patterns not only provides a new insight into TNBC subtypes but also deepens the understanding of ICGs in the tumor immune microenvironment.

Identifying cancer tissue-of-origin by a novel machine learning method based on expression quantitative trait loci

Cancer of unknown primary (CUP) refers to cancer with primary lesion unidentifiable by regular pathological and clinical diagnostic methods. This kind of cancer is extremely difficult to treat, and patients with CUP usually have a very short survival time. Recent studies have suggested that cancer treatment targeting primary lesion will significantly improve the survival of CUP patients. Thus, it is critical to develop accurate yet fast methods to infer the tissue-of-origin (TOO) of CUP. In the past years, there are a few computational methods to infer TOO based on single omics data like gene expression, methylation, somatic mutation, and so on. However, the metastasis of tumor involves the interaction of multiple levels of biological molecules. In this study, we developed a novel computational method to predict TOO of CUP patients by explicitly integrating expression quantitative trait loci (eQTL) into an XGBoost classification model. We trained our model with The Cancer Genome Atlas (TCGA) data involving over 7,000 samples across 20 types of solid tumors. In the 10-fold cross-validation, the prediction accuracy of the model with eQTL was over 0.96, better than that without eQTL. In addition, we also tested our model in an independent data downloaded from Gene Expression Omnibus (GEO) consisting of 87 samples across 4 cancer types. The model also achieved an f1-score of 0.7-1 depending on different cancer types. In summary, eQTL was an important information in inferring cancer TOO and the model might be applied in clinical routine test for CUP patients in the future.

N6-methyladenosine demethylase ALKBH5 suppresses colorectal cancer progression potentially by decreasing PHF20 mRNA methylation

BACKGROUND

As the most widespread mRNAs modification, N6-methyladenosine (m6 A) is dynamically and reversibly modulated by methyltransferases and demethylases. ALKBH5 is a major demethylase, and plays vital roles in the progression of cancers. However, the role and mechanisms of ALKBH5 in colorectal cancer (CRC) is unclear.

RESULTS

Herein, we discovered that in CRC, downregulated ALKBH5 was closely related to poor prognosis of CRC patients. Functionally, our results demonstrated that knockdown of ALKBH5 enhanced the proliferation, migration and invasion of LOVO and RKO in vitro, while overexpression of ALKBH5 inhibited the functions of these cells. The results also demonstrated that knockdown of ALKBH5 promoted subcutaneous tumorigenesis of LOVO in vivo, while overexpression of ALKBH5 suppressed this ability. Mechanistically, results from joint analyses of MeRIP-seq and RNA-seq indicated that PHF20 mRNA was a key molecule that was regulated by ALKBH5-mediated m6 A modification. Further experiments indicated that ALKBH5 may inhibit stability of PHF20 mRNA by removing the m6 A modification of PHF20 mRNA 3'UTR.

CONCLUSIONS

ALKBH5 suppresses CRC progression by decreasing PHF20 mRNA methylation. ALKBH5-mediated m6 A modification of PHF20 mRNA can serve as a hopeful strategy for the intervention and treatment of CRC.

C9ORF78 partially localizes to centromeres and plays a role in chromosome segregation

C9ORF78 is a poorly characterized protein found in diverse eukaryotes. Previous work indicated overexpression of C9ORF78 in malignant tissues indicating a possible involvement in growth regulatory pathways. Additional studies in fission yeast and humans uncover a potential function in regulating the spliceosome. In studies of GFP-tagged C9ORF78 we observed a dramatic reduction in protein abundance in cells grown to confluence and/or deprived of serum growth factors. Serum stimulation induced synchronous re-expression of the protein in HeLa cells. This effect was also observed with the endogenous protein. Overexpressing either E2F1 or N-Myc resulted in elevated C9ORF78 expression potentially explaining the serum-dependent upregulation of the protein. Immunofluorescence analysis indicates that C9ORF78 localizes to nuclei in interphase but does not appear to concentrate in speckles as would be expected for a splicing protein. Surprisingly, a subpopulation of C9ORF78 co-localizes with ACA, Mad1 and Ndc80 in mitotic cells suggesting that this protein associates with kinetochores or centromeres. Levels of C9ORF78 at the centromere/kinetochore also increased upon activation of the mitotic checkpoint. Furthermore, knocking-down C9ORF78 caused mitotic defects. These studies uncover novel mitotic function and subcellular localization of C9ORF78.

A multi-factor trafficking site on the spliceosome remodeling enzyme BRR2 recruits C9ORF78 to regulate alternative splicing

The intrinsically unstructured C9ORF78 protein was detected in spliceosomes but its role in splicing is presently unclear. We find that C9ORF78 tightly interacts with the spliceosome remodeling factor, BRR2, in vitro. Affinity purification/mass spectrometry and RNA UV-crosslinking analyses identify additional C9ORF78 interactors in spliceosomes. Cryogenic electron microscopy structures reveal how C9ORF78 and the spliceosomal B complex protein, FBP21, wrap around the C-terminal helicase cassette of BRR2 in a mutually exclusive manner. Knock-down of C9ORF78 leads to alternative NAGNAG 3'-splice site usage and exon skipping, the latter dependent on BRR2. Inspection of spliceosome structures shows that C9ORF78 could contact several detected spliceosome interactors when bound to BRR2, including the suggested 3'-splice site regulating helicase, PRPF22. Together, our data establish C9ORF78 as a late-stage splicing regulatory protein that takes advantage of a multi-factor trafficking site on BRR2, providing one explanation for suggested roles of BRR2 during splicing catalysis and alternative splicing.

Rebirth of the translational machinery: The importance of recycling ribosomes

Translation of the genetic code occurs in a cycle where ribosomes engage mRNAs, synthesize protein, and then disengage in order to repeat the process again. The final part of this process-ribosome recycling, where ribosomes dissociate from mRNAs-involves a complex molecular choreography of specific protein factors to remove the large and small subunits of the ribosome in a coordinated fashion. Errors in this process can lead to the accumulation of ribosomes at stop codons or translation of downstream open reading frames (ORFs). Ribosome recycling is also critical when a ribosome stalls during the elongation phase of translation and must be rescued to allow continued translation of the mRNA. Here we discuss the molecular interactions that drive ribosome recycling, and their regulation in the cell. We also examine the consequences of inefficient recycling with regards to disease, and its functional roles in synthesis of novel peptides, regulation of gene expression, and control of mRNA-associated proteins. Alterations in ribosome recycling efficiency have the potential to impact many cellular functions but additional work is needed to understand how this regulatory power is utilized.

PSD3 downregulation confers protection against fatty liver disease

Fatty liver disease (FLD) is a growing health issue with burdening unmet clinical needs. FLD has a genetic component but, despite the common variants already identified, there is still a missing heritability component. Using a candidate gene approach, we identify a locus (rs71519934) at the Pleckstrin and Sec7 domain-containing 3 (PSD3) gene resulting in a leucine to threonine substitution at position 186 of the protein (L186T) that reduces susceptibility to the entire spectrum of FLD in individuals at risk. PSD3 downregulation by short interfering RNA reduces intracellular lipid content in primary human hepatocytes cultured in two and three dimensions, and in human and rodent hepatoma cells. Consistent with this, Psd3 downregulation by antisense oligonucleotides in vivo protects against FLD in mice fed a non-alcoholic steatohepatitis-inducing diet. Thus, translating these results to humans, PSD3 downregulation might be a future therapeutic option for treating FLD.

Assessing kinetics and recruitment of DNA repair factors using high content screens

Repair of genetic damage is coordinated in the context of chromatin, so cells dynamically modulate accessibility at DNA breaks for the recruitment of DNA damage response (DDR) factors. The identification of chromatin factors with roles in DDR has mostly relied on loss-of-function screens while lacking robust high-throughput systems to study DNA repair. In this study, we have developed two high-throughput systems that allow the study of DNA repair kinetics and the recruitment of factors to double-strand breaks in a 384-well plate format. Using a customized gain-of-function open-reading frame library ("ChromORFeome" library), we identify chromatin factors with putative roles in the DDR. Among these, we find the PHF20 factor is excluded from DNA breaks, affecting DNA repair by competing with 53BP1 recruitment. Adaptable for genetic perturbations, small-molecule screens, and large-scale analysis of DNA repair, these resources can aid our understanding and manipulation of DNA repair.

TFDP3 as E2F Unique Partner, Has Crucial Roles in Cancer Cells and Testis

Transcription factor DP family member 3 (TFDP3) is a cancer-testis antigen, mainly expressed in normal testis and multiple cancers. TFDP3 gene (Gene ID: 51270) is located on the chromosome X and shares a high degree of sequence homology with TFDP1 and TFDP2, which can form heterodimers with E2F family members and enhance DNA-binding activity of E2Fs. In contrast to TFDP1 and TFDP2, TFDP3 downregulates E2F-mediated transcriptional activation. During DNA damage response in cancer cells, TFDP3 is induced and can inhibit E2F1-mediated apoptosis. Moreover, TFDP3 is involved in cell autophagy and epithelial-mesenchymal transition. Regarding cancer therapy opportunity, the transduction of dendritic cells with recombinant adenovirus-encoding TFDP3 can activate autologous cytotoxic T lymphocytes to target hepatoma cells. Here, we review the characterization of TFDP3, with an emphasis on the biological function and molecular mechanism. A better understanding of TFDP3 will provide new insights into the pathological mechanisms and therapeutic strategies for cancers.

40S ribosome profiling reveals distinct roles for Tma20/Tma22 (MCT-1/DENR) and Tma64 (eIF2D) in 40S subunit recycling

The recycling of ribosomes at stop codons for use in further rounds of translation is critical for efficient protein synthesis. Removal of the 60S subunit is catalyzed by the ATPase Rli1 (ABCE1) while removal of the 40S is thought to require Tma64 (eIF2D), Tma20 (MCT-1), and Tma22 (DENR). However, it remains unclear how these Tma proteins cause 40S removal and control reinitiation of downstream translation. Here we used a 40S ribosome footprinting strategy to directly observe intermediate steps of ribosome recycling in cells. Deletion of the genes encoding these Tma proteins resulted in broad accumulation of unrecycled 40S subunits at stop codons, directly establishing their role in 40S recycling. Furthermore, the Tma20/Tma22 heterodimer was responsible for a majority of 40S recycling events while Tma64 played a minor role. Introduction of an autism-associated mutation into TMA22 resulted in a loss of 40S recycling activity, linking ribosome recycling and neurological disease.

Nanoparticles of Chitosan/Poly(D,L-Lactide-Co-Glycolide) Enhanced the Immune Responses of Haemonchus contortus HCA59 Antigen in Model Mice

Background

Hepatocellular carcinoma-associated antigen 59 (HCA59) from excretory/secretory products of Haemonchus contortus is known to have the ability to modulate the functions of host cells. However, its immunogenicities using different nanoparticles adjuvants remain poorly understood.

Purpose

The study aimed to select an efficient nanoparticle antigen delivery system, which could enhance the immune responses of Haemonchus contortus HCA59 in mice.

Methods

Here, the immune responses induced by the recombinant protein of HCA59 (rHCA59) with poly-D,L-lactide-co-glycolide (PLGA) nanoparticles, Chitosan nanoparticles, mixture of PLGA and Chitosan nanoparticles (rHCA59-Chitosan-PLGA), and Freund’s complete adjuvant were observed, respectively, in mice. Cytokine and antibody levels induced by different groups were detected by ELISA assay. The effects of lymphocyte proliferations on different groups were examined using CCK-8 kit. Phenotypes of T cells and dendritic cells were analyzed by flow cytometry.

Results

On day 14 post vaccination, levels of IgM, IgG1, IgG2a, IFN-γ, IL-4, and IL-17 were significantly increased in the groups immunized with rHCA59 encapsulated with nanoparticles. After mice were vaccinated with rHCA59 loaded with Chitosan/PLGA nanoparticles, lymphocytes proliferated significantly. Additionally, the percentages of CD4⁺ T cells (CD3⁺ CD4⁺), CD8⁺ T cells (CD3⁺ CD8⁺), and dendritic cells (CD11c⁺ CD83⁺, CD11c⁺ CD86⁺) were obviously up-regulated in the mice immunized with nanoparticles, especially in the rHCA59-Chitosan-PLGA antigen delivery system group.

Conclusion

The findings of this research demonstrated that rHCA59-Chitosan-PLGA antigen delivery system could induce higher immune responses in mice model and indicated that rHCA59 might be a good candidate molecule to develop nanovaccines against Haemonchus contortus in future study.

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.

Haemonchus contortus hepatocellular carcinoma-associated antigen 59 with poly (lactic-co-glycolic acid): A promising nanovaccine candidate against Haemonchus contortus infection

Hepatocellular carcinoma-associated antigen 59 (HCA59), one of significant excretory/secretory products of Haemonchus contortus (HcESPs), is identified to have immunomodulatory eff ;ects on host cells. However, protection potential of the molecule in H. contortus remains poorly understood. In this study, H. contortus recombinant HCA59 protein amalgamated with poly (lactic-co-glycolic acid) (PLGA) nanoparticle adjuvant was tested for its protection against H. contortus infection in goats. Fifteen goats were allocated into three groups. On days 0 and 14, rHCA59 group was immunized with PLGA nanoparticles encapsulated with recombinant protein HCA59 (rHCA59-PLGA) respectively. Positive control group was unvaccinated, but challenged with H. contortus third stage larvae (L3). Negative control group was unvaccinated and unchallenged with L3. Goats in rHCA59 group and positive control group were challenged with 8000 H. contortus L3 after 14 days of the second immunization. Following immunization, high level of sera IgG, IgA, and IgE, as well as significantly high production of IL-4 and IL-9 was produced in rHCA59 group. After L3 challenge, the level of IL-17 and TGF-β in rHCA59 group increased obviously. Meanwhile, the fecal eggs and the abomasal worm burdens in rHCA59 group was reduced by 44.1 % and 54.6 %, respectively. The studies suggested that rHCA59-PLGA nanoparticles conferred partial protection and could be a good candidate for the development of nanovaccines against H. contortus infection in goats.

Emerging roles of the MAGE protein family in stress response pathways

The melanoma antigen (MAGE) proteins all contain a MAGE homology domain. MAGE genes are conserved in all eukaryotes and have expanded from a single gene in lower eukaryotes to ∼40 genes in humans and mice. Whereas some MAGEs are ubiquitously expressed in tissues, others are expressed in only germ cells with aberrant reactivation in multiple cancers. Much of the initial research on MAGEs focused on exploiting their antigenicity and restricted expression pattern to target them with cancer immunotherapy. Beyond their potential clinical application and role in tumorigenesis, recent studies have shown that MAGE proteins regulate diverse cellular and developmental pathways, implicating them in many diseases besides cancer, including lung, renal, and neurodevelopmental disorders. At the molecular level, many MAGEs bind to E3 RING ubiquitin ligases and, thus, regulate their substrate specificity, ligase activity, and subcellular localization. On a broader scale, the MAGE genes likely expanded in eutherian mammals to protect the germline from environmental stress and aid in stress adaptation, and this stress tolerance may explain why many cancers aberrantly express MAGEs Here, we present an updated, comprehensive review on the MAGE family that highlights general characteristics, emphasizes recent comparative studies in mice, and describes the diverse functions exerted by individual MAGEs.

Cancer testis antigens in myelodysplastic syndromes revisited: a targeted RNA-seq approach

Cancer-Testis antigens (CTA) are named after the tissues where they are mainly expressed: in germinal and in cancer cells, a process that mimics many gametogenesis features. Mapping accurately the CTA gene expression signature in myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) is a prerequisite for downstream immune target-discovery projects. In this study, we take advantage of the use of azacitidine to treat high-risk MDS and CMML to draw the CTAs landscape, before and after treatment, using an ad hoc targeted RNA sequencing (RNA-seq) design for this group of low transcript genes. In 19 patients, 196 CTAs were detected at baseline. Azacitidine did not change the number of CTAs expressed, but it significantly increased or decreased expression in nine and five CTAs, respectively. TFDP3 and DDX53, emerged as the main candidates for immunotherapeutic targeting, as they showed three main features: i) a significant derepression on day +28 of cycle one in those patients who achieved complete remission with hypomethylating treatment (FC = 6, p = .008; FC = 2.1, p = .008, respectively), ii) similar dynamics at the protein level to what was observed at the RNA layer, and iii) to elicit significant specific cytotoxic immune responses detected by TFDP3 and DDX53 HLA-A*0201 tetramers. Our study addresses the unmet landscape of CTAs expression in MDS and CMML and revealed a previously unrecognized TFDP3 and DDX53 reactivation, detectable in plasma and able to elicit a specific immune response after one cycle of azacitidine.

Recent Advances: The Imbalance of Immune Cells and Cytokines in the Pathogenesis of Hepatocellular Carcinoma

Recent advancement in the immunological understanding of genesis of hepatocellular carcinoma (HCC) has implicated a decline in anti-tumour immunity on the background of chronic inflammatory state of liver parenchyma. The development of HCC involves a network of immunological activity in the tumour microenvironment involving continuous interaction between tumour and stromal cells. The reduction in anti-tumour immunity is secondary to changes in various immune cells and cytokines, and the tumour microenvironment plays a critical role in modulating the process of liver fibrosis, hepatocarcinogenesis, epithelial-mesenchymal transition (EMT), tumor invasion and metastasis. Thus, it is considered as one of primary factor behind the despicable tumour behavior and observed poor survival; along with increased risk of recurrence following treatment in HCC. The primary intent of the present review is to facilitate the understanding of the complex network of immunological interactions of various immune cells, cytokines and tumour cells associated with the development and progression of HCC.

MAGEC2 Correlates With Unfavorable Prognosis And Promotes Tumor Development In HCC Via Epithelial-Mesenchymal Transition

Purpose

Although MAGEC2 was first cloned from a human hepatocellular carcinoma (HCC) cDNA library by serum screening, the detailed attributes of MAGEC2 in HCC have rarely been elucidated.

Patients and methods

In this study, The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases were consulted to analyse the expression of MAGEC2 mRNA in liver cancer. Immunohistochemistry (IHC) analysis was performed to detect MAGEC2 expression in HCC, and the relationship between MAGEC2 expression and the clinicopathological characteristics of HCC patients was evaluated. Then, we employed the short hairpin (sh)RNA-mediated knockdown of MAGEC2 in HCC cell lines to explore the function of MAGEC2 in HCC development. Finally, the expression of epithelial-mesenchymal transition (EMT) markers in HCC xenografts and clinical samples was investigated.

Results

The results showed a remarkably higher level of MAGEC2 expression in HCC tissues than in noncancerous tissues, and MAGEC2 expression could be used as an independent prognostic factor for overall survival in HCC. Moreover, sh-MAGEC2 inhibited a series of HCC malignant behaviours both in vitro and in vivo. Finally, decreased MAGEC2 expression and low levels of EMT markers were detected in sh-MAGEC2 xenografts, while increased MAGEC2 expression and high levels of EMT markers were observed in invasive and metastatic HCC samples.

Conclusion

Taken together, our data imply that MAGEC2 is a novel prognostic marker for HCC and that MAGEC2 significantly promotes HCC tumourigenesis by inducing EMT. Targeting MAGEC2 may provide a promising therapeutic strategy for HCC treatment.

TMEM176A and TMEM176B Are Candidate Regulators of Inhibition of Dendritic Cell Maturation and Function after Chronic Spinal Cord Injury

Inhibition of dendritic cell maturation and activation, together with abnormal functioning of cell-mediated immunity, has been reported in chronic spinal cord injury (SCI). The development of immune-based therapies could: 1) prevent or slow down limit further tissue damage in chronic SCI, and 2) promote tissue regeneration. To identify novel candidate molecular pathways mediating SCI-induced immune changes, we performed whole-genome microarray and molecular pathway analyses. Subjects with motor complete chronic SCI (> 2 years post-injury) and uninjured controls were selected from an ongoing study. Microarray analysis was performed with RNA extracted from circulating monocytes. Partek Genomic Suite (PGS) software was used to limit the 54,000 gene list to only those genes up-regulated or down-regulated by 2-fold or more in SCI compared with control. Pathway analyses were performed with Ingenuity Systems IPA software to identify biological pathways of interest involving differentially expressed genes. Genes of interest were then confirmed by quantitative PCR (qPCR). Six SCI subjects and five uninjured controls were included in the final analyses. A molecular pathway related to immune cell trafficking was identified as being significantly upregulated in the SCI subjects. Two genes in that network, transmembrane domain protein (TMEM)176A and TMEM176B, were notable for the magnitude of overexpression. Dendritic cells have been shown to mediate recovery and/or protective autoimmunity in central nervous system injuries and have the capacity to induce neuroprotection and neurogenesis in stroke patients. High TMEM176A and TMEM176B levels have been shown to prevent dendritic cell maturation and inhibit dendritic cell activity in the general population. Here, we report overexpression of both genes in SCI compared with control subjects. Thus, we propose that TMEM176A and TMEM176B are candidate genes involved in inhibiting protective immune responses in SCI. This study may support future research aimed at developing new targets for therapies to promote immune system-mediated neuroprotection and recovery in SCI.

Combined Use of Indirect ELISA and Western Blotting with Recombinant Hepatocellular Carcinoma-Associated Antigen 59 Is a Potential Immunodiagnostic Tool for the Detection of Prepatent Haemonchus contortus Infection in Goat

Simple Summary

The accurate and early diagnosis of Haemonchus contortus infection is crucial for effective control. Early stage detection of H. contortus infection has not been attempted in goat, even though both immature worm and fourth larval stage are blood sucking. This study was carried out to detect the H. contortus infection during early stage in goat. The results of this study assessed that rHc-HCA59 could detect the antibody in H. contortus infected goats’ sera during early period with good sensitivity and specificity using immunodiagnostic techniques. Our findings illustrated that combined use of ELISA and western blotting based on rHc-HCA59 is a powerful tool for early detection of H. contortus infection in goats.

Abstract

Haemonchus contortus is recognized as one of the important health problems in small ruminants, leading to reduced production and economic loss for farmers worldwide. Prepatent diagnosis of H. contortus infection is crucial to improve control strategies as this helminth may remove up to one-fifth of total erythrocytes and may cause anemia, edema, diarrhea, and ultimately death in young animals. In this study, one of the excretory and secretory products, rHc-HCA59, was purified and used as antigen to detect specific antibodies in H. contortus infected goats during prepatent stage of infection using indirect enzyme linked immunosorbent assay (ELISA) as screening test. All goats (n = 38) were housed indoor, experimentally infected with 8000 infective larvae (L3) of H. contortus, and serum samples were collected prior to infection and at 14th day of infection. Immunoblotting was performed to confirm the results of indirect ELISA, evaluate the cross reactivity against rHc-HCA59 in sera of most common co-infecting parasites and rectify the false negative samples. Furthermore, three different batches of rHc-HCA59 were produced to evaluate the repeatability of ELISA. No eggs were detected in feces of all goats collected at 7th and 14th day of infection but, H. contortus eggs were detected at 21 days post infection in the feces. Indirect ELISA performed in this study showed 87% sensitivity and 100% specificity. The western blot analysis confirmed immunoreactivity in serum samples which scored positive in indirect ELISA and recognized the samples as negative which had OD₄₅₀ lower than negative cut-off value in indirect ELISA. Furthermore, all false negative sera (n = 5) that had OD₄₅₀ value between positive and negative cut-off value in rHc-HCA59 based ELISA were clearly positive in western blot. Moreover, no cross-reactivity was detected in ELISA and western blotting against rHc-HCA59 in positive sera of Toxoplasma gondii, Fasciola hepatica, and Trichinella spiralis. The results of this study concluded that combined use of indirect ELISA and western blotting with rHc-HCA59 is a potential immunodiagnostic tool for the detection of H. contortus infection during prepatent period in goats.

Therapeutic challenges and current immunomodulatory strategies in targeting the immunosuppressive pancreatic tumor microenvironment

BACKGROUND

Pancreatic cancer is one of the most lethal type of cancers, with an overall five-year survival rate of less than 5%. It is usually diagnosed at an advanced stage with limited therapeutic options. To date, no effective treatment options have demonstrated long-term benefits in advanced pancreatic cancer patients. Compared with other cancers, pancreatic cancer exhibits remarkable resistance to conventional therapy and possesses a highly immunosuppressive tumor microenvironment (TME).

MAIN BODY

In this review, we summarized the evidence and unique properties of TME in pancreatic cancer that may contribute to its resistance towards immunotherapies as well as strategies to overcome those barriers. We reviewed the current strategies and future perspectives of combination therapies that (1) promote T cell priming through tumor associated antigen presentation; (2) inhibit tumor immunosuppressive environment; and (3) break-down the desmoplastic barrier which improves tumor infiltrating lymphocytes entry into the TME.

CONCLUSIONS

It is imperative for clinicians and scientists to understand tumor immunology, identify novel biomarkers, and optimize the position of immunotherapy in therapeutic sequence, in order to improve pancreatic cancer clinical trial outcomes. Our collaborative efforts in targeting pancreatic TME will be the mainstay of achieving better clinical prognosis among pancreatic cancer patients. Ultimately, pancreatic cancer will be a treatable medical condition instead of a death sentence for a patient.

Hepatocellular carcinoma-associated antigen 59 of Haemonchus contortus modulates the functions of PBMCs and the differentiation and maturation of monocyte-derived dendritic cells of goats in vitro

BACKGROUND

Hepatocellular carcinoma-associated antigen 59 (HCA59), which is one of the most important excretory/secretory products of Haemonchus contortus (HcESPs), is known to have antigenic functions. However, its immunomodulatory effects on host cells are poorly understood.

METHODS

Here, we cloned the HCA59 gene and expressed the recombinant protein of HCA59 (rHCA59). Binding activities of rHCA59 to goat peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) were checked by immunofluorescence assay (IFA) and the immunoregulatory effects of rHCA59 on cytokine secretions, cell migration, cell proliferation, nitric oxide production, and changes in expression of genes in related pathways were observed by co-incubation of rHCA59 with goat PBMCs and DCs. Monocyte phagocytosis and characterization of goat blood DC subsets were detected by flow cytometry.

RESULTS

The IFA results revealed that rHCA59 could bind to PBMCs and DCs. Treatment of PBMCs with rHCA59 significantly increased cellular proliferation and NO production in a dose-dependent manner, while cell migration was vigorously blocked. Treatment with rHCA59 significantly suppressed monocytes phagocytosis. The quantity of surface marker CD80 on DCs increased significantly after rHCA59 treatment. In addition, the expression of genes included in the WNT pathway was related to the differentiation and maturation of DCs, and the production of IL-10 and IL-17 produced by PBMCs was altered.

CONCLUSIONS

Our findings illustrated that rHCA59 could enhance host immune responses by regulating the functions of goat PBMCs and DCs, which would benefit our understanding of HCA59 from parasitic nematodes contributing to the mechanism of parasitic immune evasion.

Epigenetic silencing of TMEM176A activates ERK signaling in human hepatocellular carcinoma

Background

The role of TMEM176A in human hepatocellular carcinoma (HCC) is unknown. This study explored the epigenetic regulation and function of TMEM176A in human HCC.

Materials and methods

Twelve HCC cell lines and 126 cases of primary cancer were analyzed. Methylation-specific PCR, immunohistochemistry, flow cytometry, and xenograft mouse models were employed.

Results

TMEM176A was highly expressed in SNU387, SNU182, Huh1, and SNU475 cells; reduced expression was observed in HepG2 and PLC/PRF/5 cells; and no expression was found in SNU449, HBXF344, SMMC7721, Huh7, and LM3 cells. Unmethylation of the TMEM176A promoter was detected in SNU387, SNU182, Huh1, and SNU475 cells; partial methylation was observed in HepG2 and PLC/PRF/5 cells; and complete methylation was found in SNU449, HBXF344, SMMC7721, Huh7, and LM3 cells. Upon treatment with 5-Aza-2-deoxycytidine, re-expression of TMEM176A was detected in SNU449, HBXF344, SMMC7721, Huh7, and LM3 cells; increased expression of TMEM176A was observed in HepG2 and PLC/PRF/5 cells; and no expression changes were found in SNU387, SNU182, Huh1, and SNU475 cells. The TMEM176A promoter region was methylated in 75.4% (95/126) of primary human HCC. Reduced expression of TMEM176A was associated with promoter region methylation (P < 0.05). No association was found between TMEM176A promoter methylation and age, gender, HBV infection, liver cirrhosis, tumor size, lymph node metastasis, vessel cancerous embolus, number of lesions, and TNM stage (all P > 0.05). These results demonstrated that the expression of TMEM176A is regulated by promoter region methylation. Methylation of the TMEM176A promoter was significantly associated with tumor cell differentiation (P < 0.05) and was an independent prognostic factor for poor 3-year overall survival (OS, P < 0.05). TMEM176A expression induced cell apoptosis; inhibited cell proliferation, migration, and invasion; suppressed human HCC cell xenograft growth in mice; and inhibited ERK signaling in HCC cells.

Conclusion

The promoter region of TMEM176A is frequently methylated in human HCC, and the expression of TMEM176A is regulated by promoter region methylation. Methylation of the TMEM176A promoter may serve as a diagnostic and prognostic marker in HCC. TMEM176A suppresses HCC growth by inhibiting the ERK signaling pathway.

Quantitative Analysis of Seven New Prostate Cancer Biomarkers and the Potential Future of the 'Biomarker Laboratory'

Prostate cancer is the third highest cause of male mortality in the developed world, with the burden of the disease increasing dramatically with demographic change. There are significant limitations to the current diagnostic regimens and no established effective screening modality. To this end, research has discovered hundreds of potential ‘biomarkers’ that may one day be of use in screening, diagnosis or prognostication. However, the barriers to bringing biomarkers to clinical evaluation and eventually into clinical usage have yet to be realised. This is an operational challenge that requires some new thinking and development of paradigms to increase the efficiency of the laboratory process and add ‘value’ to the clinician. Value comes in various forms, whether it be a process that is seamlessly integrated into the hospital laboratory environment or one that can provide additional ‘information’ for the clinical pathologist in terms of risk profiling. We describe, herein, an efficient and tissue-conserving pipeline that uses Tissue Microarrays in a semi-automated process that could, one day, be integrated into the hospital laboratory domain, using seven putative prostate cancer biomarkers for illustration.

TFDP3 confers chemoresistance in minimal residual disease within childhood T-cell acute lymphoblastic leukemia

Acquired drug resistance in childhood T-cell acute lymphoblastic leukemia (T-ALL) remains a significant clinical problem. In this study, a novel gene therapy target for childhood T-ALL to overcome chemoresistance was discovered: TFDP3 increased in the minimal residual disease (MRD) positive childhood T-ALL patients. Then, we established a preclinical model of resistance to induction therapy to examine the functional relevance of TFDP3 to chemoresistance in MRD derived from Jurkat/E6-1. Jurkat xenografts in NOD/SCID mice were exposed to a four drug combination (VXLD) of vincristine (VCR), dexamethasone (DEX), L-asparaginase (L-asp) and daunorubicin (DNR). During the 4-week VXLD treatment, the level of TFDP3 increased 4-fold. High expression of TFDP3 was identified in the re-emerging lines (Jurkat/MRD) with increased chemoresistance, which is correlated with partially promoter demethylation of TFDP3. Downregulation of TFDP3 by RNA interference reversed chemoresistance in Jurkat/MRD accompanied by reinstated E2F1 activity that coincided with increased levels of p53, p73, and associated proapoptotic target genes. Importantly, TFDP3 silencing in vivo induced apparent benefit to overcome chemoresistance in combination with VXLD treatment. Collectively, TFDP3 confers chemoresistance in MRD within childhood T-ALL, indicating that TFDP3 is a potential gene therapy target for residual cancer.

The Immunome of Colon Cancer: Functional In Silico Analysis of Antigenic Proteins Deduced from IgG Microarray Profiling

Characterization of the colon cancer immunome and its autoantibody signature from differentially-reactive antigens (DIRAGs) could provide insights into aberrant cellular mechanisms or enriched networks associated with diseases. The purpose of this study was to characterize the antibody profile of plasma samples from 32 colorectal cancer (CRC) patients and 32 controls using proteins isolated from 15,417 human cDNA expression clones on microarrays. 671 unique DIRAGs were identified and 632 were more highly reactive in CRC samples. Bioinformatics analyses reveal that compared to control samples, the immunoproteomic IgG profiling of CRC samples is mainly associated with cell death, survival, and proliferation pathways, especially proteins involved in EIF2 and mTOR signaling. Ribosomal proteins (e.g., RPL7, RPL22, and RPL27A) and CRC-related genes such as APC, AXIN1, E2F4, MSH2, PMS2, and TP53 were highly enriched. In addition, differential pathways were observed between the CRC and control samples. Furthermore, 103 DIRAGs were reported in the SEREX antigen database, demonstrating our ability to identify known and new reactive antigens. We also found an overlap of 7 antigens with 48 “CRC genes.” These data indicate that immunomics profiling on protein microarrays is able to reveal the complexity of immune responses in cancerous diseases and faithfully reflects the underlying pathology.

Overexpressed ACBD3 has prognostic value in human breast cancer and promotes the self-renewal potential of breast cancer cells by activating the Wnt/beta-catenin signaling pathway

Acyl-CoA binding domain containing 3 (ACBD3) is involved in the maintenance of Golgi structure and function through its interaction with the integral membrane protein. However, the clinical significance and biological role of ACBD3 in breast cancer remain unclear. Herein, we found that the mRNA and protein levels of ACBD3 were markedly up-regulated in breast cancer cells and tissues. Immunohistochemical analysis of breast cancer tissues demonstrated that ACBD3 overexpression was significantly associated with advanced clinicopathological features. Univariate and multivariate analysis indicated that ACBD3 overexpression correlates with poor prognosis in breast cancer. Furthermore, overexpressing ACBD3 promoted, while silencing ACBD3 inhibited, self-renewal and tumorigenesis in breast cancer cells in vitro and in vivo respectively. Importantly, upregulating ACBD3 promoted the self-renewal and tumorigenesis of breast cancer cells via activating the Wnt/beta-catenin signaling, and the pro-self-renewal effect of ACBD3 in breast cancer was antagonized by the Wnt signaling inhibitor TCF4-siRNA and Lef1-siRNA.These findings indicate that ACBD3 may represent candidate therapeutic targets to enable the elimination of breast cancer stem cells, providing the preclinical proof-of-concept for the prevention and treatment of breast cancer.

Cancer‑testis antigen HCA587/MAGEC2 interacts with the general transcription coactivator TAF9 in cancer cells

Hepatocellular carcinoma-associated antigen 587/melanoma antigen gene (HCA587/MAGEC2) is a cancer‑testis antigen, which is highly expressed in various types of tumors, but not in normal tissues with the exception of male germ‑line cells. HCA587/MAGEC2 has been previously recognized as a tumor‑specific target for immunotherapy; however, its biological functions have been relatively understudied. To investigate the function of HCA587/MAGEC2, the amino acid sequence of HCA587/MAGEC2 was analyzed by bioinformatics and it was demonstrated that HCA587/MAGEC2 contains a 9‑amino acid transactivation domain which may mediate the interaction of most transcription factors with TATA‑box binding protein associated factor 9 (TAF9), a general transcription coactivator. Co‑immunoprecipitation experiments revealed that HCA587/MAGEC2 interacted with TAF9 in transfected 293T and in A375 melanoma cells endogenously expressing HCA587/MAGEC2, and confirmed the endogenous interaction of HCA587/MAGEC2 and TAF9 within cells. Endogenous HCA587/MAGEC2 and TAF9 were demonstrated to be co‑localized principally in the nucleus of tumor cells using immunofluorescence. Glutathione-S-transferase pull‑down experiments demonstrated that HCA587/MAGEC2 interacts with TAF9 directly and the conserved region in the TAF9 may becrucial for HCA587/MAGEC2 binding. The present study demonstrated that the cancer‑testis antigen HCA587/MAGEC2 directly interacted with TAF9, which may provide novel information for identifying the oncogenic functions of HCA587/MAGEC2 in tumor cells.

Non-AUG translation: a new start for protein synthesis in eukaryotes

This review by Kearse and Wilusz discusses the profound impact of non-AUG start codons in eukaryotic translation. It describes how misregulation of non-AUG initiation events contributes to multiple human diseases, including cancer and neurodegeneration, and how modulation of non-AUG usage may represent a novel therapeutic strategy.

Although it was long thought that eukaryotic translation almost always initiates at an AUG start codon, recent advancements in ribosome footprint mapping have revealed that non-AUG start codons are used at an astonishing frequency. These non-AUG initiation events are not simply errors but instead are used to generate or regulate proteins with key cellular functions; for example, during development or stress. Misregulation of non-AUG initiation events contributes to multiple human diseases, including cancer and neurodegeneration, and modulation of non-AUG usage may represent a novel therapeutic strategy. It is thus becoming increasingly clear that start codon selection is regulated by many trans-acting initiation factors as well as sequence/structural elements within messenger RNAs and that non-AUG translation has a profound impact on cellular states.

Serum levels of anti-sperm-associated antigen 9 antibody are elevated in patients with hepatocellular carcinoma

At present, there is a high incidence of viral hepatitis and high mortality rates due to hepatocellular carcinoma (HCC) in China. In the current study, the quantification of antibodies against the cancer-testis antigen sperm-associated antigen 9 (SPAG9), alone and combined with α-fetoprotein (AFP), were evaluated as biomarkers for the diagnosis of HCC. The levels of anti-SPAG9 antibody and AFP were quantified in serum samples from patients with HCC and hepatitis or cirrhosis, as well as healthy volunteers. The results revealed that the serum levels of anti-SPAG9 immunoglobulin G antibody in patients with HCC were significantly higher compared with those in patients with hepatitis/cirrhosis and healthy controls. Using receiver operator characteristic curves, the area under the curve (AUC, 0.870) of SPAG9 as a diagnostic marker of HCC was significant [P<0.001; 95% confidence interval (CI), 0.793-0.947], whereas the AUC of AFP was 0.832 (P<0.001; 95% CI, 0.736-0.928). Serum anti-SPAG9 antibody levels exhibited significant potential for the differential diagnosis of HCC, with an AUC value of 0.729, (P=0.008; 95% CI, 0.559-0.899). Similarly, serum AFP levels exhibited significant value for the differential diagnosis of HCC, with an AUC value of 0.842 (P<0.001; 95% CI, 0.732-0.953). When combined with quantification of AFP, the diagnostic sensitivity and specificity of anti-SPAG9 levels were increased. In summary, the results suggested that anti-SPAG9 antibody is a potential early diagnostic marker of HCC.

Identification of genes and pathways potentially related to PHF20 by gene expression profile analysis of glioblastoma U87 cell line

Background

Glioblastoma is the most common and aggressive brain tumor associated with a poor prognosis. Plant homeodomain finger protein 20 (PHF20) is highly expressed in primary human gliomas and its expression is associated with tumor grade. However, the molecular mechanism by which PHF20 regulates glioblastoma remains poorly understood.

Methods

Genome wide gene expression analysis was performed to identify differentially expressed genes (DEGs) in U87 cells with PHF20 gene knockdown. Gene ontology (GO) and pathway enrichment analyses were performed to investigate the functions and pathways of DEGs. Pathway-net and signal-net analyses were conducted to identify the key genes and pathways related to PHF20.

Results

Expression of 540 genes, including FEN1 and CCL3, were significantly altered upon PHF20 gene silencing. GO analysis results showed that DEGs were significantly enriched in small molecule metabolic and apoptotic processes. Pathway analysis indicated that DEGs were mainly involved in cancer and metabolic pathways. The MAPK, apoptosis and p53 signaling pathways were identified as the hub pathways in the pathway network, while PLCB1, NRAS and PIK3 s were hub genes in the signaling network.

Conclusions

Our findings indicated that PHF20 is a pivotal upstream regulator. It affects the occurrence and development of glioma by regulating a series of tumor-related genes, such as FEN1, CCL3, PLCB1, NRAS and PIK3s, and activation of apoptosis signaling pathways. Therefore, PHF20 might be a novel biomarker for early diagnosis, and a potential target for glioblastoma therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-017-0459-x) contains supplementary material, which is available to authorized users.

Methylation of TMEM176A is an independent prognostic marker and is involved in human colorectal cancer development

Colorectal cancer (CRC) is the third most common malignancy and the fourth most common cause of cancer related death worldwide. This study was designed to find tumor suppressors involved in CRC development by performing RNA-seq. Eight CRC cell lines and 130 cases of primary CRC samples were used. RNA-seq, methylation-specific PCR (MSP), flow cytometry, transwell assays, and a xenograft mouse model were used. Reduction of TMEM176A expression was confirmed in human CRC cells by RNA-seq. TMEM176A was expressed in LS180 and SW620 cells, loss of TMEM176A expression was observed in LOVO, HCT116, RKO, and DLD1 cells, and reduced TMEM176A expression was found in HT29 and SW480 cells. Unmethylation of the TMEM176A promoter was found in LS180 and SW620 cells, whereas complete methylation was found in LOVO, HCT116, RKO, and DLD1 cells, and partial methylation was found in HT29 and SW480 cells. Promoter region methylation correlated with loss of/reduced expression of TMEM176A. Re-expression of TMEM176A was induced by 5-aza-2'-deoxycytidine. TMEM176A was methylated in 50.77% of primary colorectal cancers. Methylation of TMEM176A was associated with tumor metastasis (P<0.05) and was an independent prognostic factor for 5-year overall survival (OS) according to Cox proportional hazards model analysis (P<0.05). TMEM176A induced apoptosis and inhibited cell migration and invasion in CRC cells. TMEM176A suppressed CRC cell growth both in vitro and in vivo. Our results suggest that expression of TMEM176A is regulated by promoter region methylation. TMEM176A methylation is an independent prognostic marker for 5-year OS in CRC, and may act as a tumor suppressor in CRC.

Apaf-1: Regulation and function in cell death

Apoptosis, a form of programmed cell death, is responsible for eliminating damaged or unnecessary cells in multicellular organisms. Various types of intracellular stress trigger apoptosis by induction of cytochrome c release from mitochondria into the cytosol. Apoptotic protease activating factor-1 (Apaf-1) is a key molecule in the intrinsic or mitochondrial pathway of apoptosis, which oligomerizes in response to cytochrome c release and forms a large complex known as apoptosome. Procaspase-9, an initiator caspase in the mitochondrial pathway, is recruited and activated by the apoptosome leading to downstream caspase-3 processing. Various cellular proteins and small molecules can modulate apoptosome formation and function directly or indirectly. Despite recent progress in understanding the mitochondrial pathway of apoptosis, numerous questions such as the molecular mechanism of Apaf-1 oligomerization and caspase-9 activation remain poorly understood. In addition, reports have emerged showing non-apoptotic functions for Apaf-1. The current review summarizes the latest findings regarding structure-function relationship of Apaf-1 as well as its modifiers.

TFDP3 Regulates Epithelial-Mesenchymal Transition in Breast Cancer

Breast cancer remains a lethal disease to women due to lymph node metastasis, the tumor microenvironment, secondary resistance and other unknown factors. Several important transcription factors involved in this disease, such as PTEN, p53 and beta-catenin, have been identified and researched in-depth as candidates for targeted therapy in breast cancer. TFDP3 is a new, promising candidate for transcriptional regulation in breast cancer, although it was first identified in hepatocellular carcinoma. Here, we demonstrate that TFDP3 is expressed in a variety of malignancies, normal testis tissue and breast cancer cell lines and thus provide evidence that TFDP3 is a cancer-testis antigen. We illustrate that overexpression or silencing TFDP3 interferes with epithelial-mesenchymal transition but does not influence cell proliferation, indicating that the TFDP3 protein acts as a transcription factor during epithelial-mesenchymal transition. These data highlight that TFDP3 is expressed in breast cancer, that it is a member of the cancer-testis antigen family and that it functions as a regulator in epithelial-mesenchymal transition.

Cancer-testis antigen MAGE-C2 binds Rbx1 and inhibits ubiquitin ligase-mediated turnover of cyclin E

Cancer-testis antigen MAGE-C2 is normally expressed in testis but aberrantly expressed in various kinds of tumors. Its functions in tumor cells are mostly unknown. Here, we show that MAGE-C2 binds directly to the RING domain protein Rbx1, and participates in Skp1-Cullin1-F box protein (SCF) complex. Furthermore, MAGE-C2 can inhibit the E3 ubiquitin ligase activity of SCF complex. Ablation of endogenous MAGE-C2 decreases the level of cyclin E and accelerates cyclin E turnover by inhibiting ubiquitin-mediated proteasome degradation. Overexpression of MAGE-C2 increases the level of cyclin E and promotes G1-S transition and cell proliferation, and the results are further confirmed by knockdown of MAGE-C2. Overall, the study indicates that MAGE-C2 is involved in SCF complex and increases the stability of cyclin E in tumor cells.

Arf proteins in cancer cell migration

Members of the ADP-ribosylation factor (Arf) family of small GTP-binding (G) proteins regulate several aspects of membrane trafficking, such as vesicle budding, tethering and cytoskeleton organization. Arf family members, including Arf-like (Arl) proteins have been implicated in several essential cellular functions, like cell spreading and migration. These functions are used by cancer cells to disseminate and invade the tissues surrounding the primary tumor, leading to the formation of metastases. Indeed, Arf and Arl proteins, as well as their guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) have been found to be abnormally expressed in different cancer cell types and human cancers. Here, we review the current evidence supporting the involvement of Arf family proteins and their GEFs and GAPs in cancer progression, focusing on 3 different mechanisms: cell-cell adhesion, integrin internalization and recycling, and actin cytoskeleton remodeling.

MAGE-C2-Specific TCRs Combined with Epigenetic Drug-Enhanced Antigenicity Yield Robust and Tumor-Selective T Cell Responses

Adoptive T cell therapy has shown significant clinical success for patients with advanced melanoma and other tumors. Further development of T cell therapy requires improved strategies to select effective, yet nonself-reactive, TCRs. In this study, we isolated 10 TCR sequences against four MAGE-C2 (MC2) epitopes from melanoma patients who showed clinical responses following vaccination that were accompanied by significant frequencies of anti-MC2 CD8 T cells in blood and tumor without apparent side effects. We introduced these TCRs into T cells, pretreated tumor cells of different histological origins with the epigenetic drugs azacytidine and valproate, and tested tumor and self-reactivities of these TCRs. Pretreatment of tumor cells upregulated MC2 gene expression and enhanced recognition by T cells. In contrast, a panel of normal cell types did not express MC2 mRNA, and similar pretreatment did not result in recognition by MC2-directed T cells. Interestingly, the expression levels of MC2, but not those of CD80, CD86, or programmed death-ligand 1 or 2, correlated with T cell responsiveness. One of the tested TCRs consistently recognized pretreated MC2(+) cell lines from melanoma, head and neck, bladder, and triple-negative breast cancers but showed no response to MHC-eluted peptides or peptides highly similar to MC2. We conclude that targeting MC2 Ag, combined with epigenetic drug-enhanced antigenicity, allows for significant and tumor-selective T cell responses.

Distinct subcellular localization of alternative splicing variants of EFA6D, a guanine nucleotide exchange factor for Arf6, in the mouse brain

EFA6D (guanine nucleotide exchange factor for ADP-ribosylation factor 6 [Arf6]D) is also known as EFA6R, Psd3, and HCA67. It is the fourth member of the EFA6 family with guanine nucleotide exchange activity for Arf6, a small guanosine triphosphatase (GTPase) that regulates endosomal trafficking and actin cytoskeleton remodeling. We propose a classification and nomenclature of 10 EFA6D variants deposited in the GenBank database as EFA6D1a, 1b, 1c, 1d, 1s, 2a, 2b, 2c, 2d, and 2s based on the combination of N-terminal and C-terminal insertions. Polymerase chain reaction analysis showed the expression of all EFA6D variants except for variants a and d in the adult mouse brain. Immunoblotting analysis with novel variant-specific antibodies showed the endogenous expression of EFA6D1b, EFA6D1c, and EFA6D1s at the protein level, with the highest expression being EFA6D1s, in the brain. Immunoblotting analysis of forebrain subcellular fractions showed the distinct subcellular distribution of EFA6D1b/c and EFA6D1s. The immunohistochemical analysis revealed distinct but overlapping immunoreactive patterns between EFA6D1b/c and EFA6D1s in the mouse brain. In immunoelectron microscopic analyses of the hippocampal CA3 region, EFA6D1b/c was present predominantly in the mossy fiber axons of dentate granule cells, whereas EFA6D1s was present abundantly in the cell bodies, dendritic shafts, and spines of hippocampal pyramidal cells. These results provide the first anatomical evidence suggesting the functional diversity of EFA6D variants, particularly EFA6D1b/c and EFA6D1s, in neurons. J. Comp. Neurol. 524:2531-2552, 2016. © 2016 Wiley Periodicals, Inc.

MicroRNA-874 Functions as a Tumor Suppressor by Targeting Cancer/Testis Antigen HCA587/MAGE-C2

Cancer/testis antigen HCA587/MAGE-C2 has been considered as a tumor specific target for immunotherapy. It has been reported that HCA587/MAGE-C2 plays an active role in tumorigenesis by promoting the growth and survival of tumor cells. However, the regulation of HCA587/MAGE-C2 expression in cancer cells remains largely unknown. MicroRNAs (miRNAs), a large family of gene regulators, have been shown to negatively regulate the expression of important cancer-related genes and contribute to the initiation and development of cancers. In this study, we conducted searches of miRNAs that regulate HCA587/MAGE-C2 expression. We combined bioinformatics tools with biological validation assays to demonstrate that HCA587/MAGE-C2 is a direct target of microRNA-874 (miR-874). Furthermore, we investigated the expression levels of miR-874 in human hepatocellular carcinoma tissues and paired adjacent normal tissues by stem-loop reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The results revealed a significant downregulation of miR-874 expression in tumor tissues compared to adjacent normal tissues. Finally, we demonstrated that overexpression of miR-874, as well as HCA587/MAGE-C2 silencing, resulted in suppression of tumor cell proliferation and invasion. Moreover, the inhibition effects of miR-874 on cell proliferation and invasion were reversed by co-expression of HCA587/MAGE-C2 in A375 cells. Taken together, our data demonstrated that HCA587/MAGE-C2 is a direct target of miR-874, and miR-874 may function as a tumor suppressive miRNA, at least in part, by negatively regulating HCA587/MAGE-C2 expression in cancer cells.

Could the eIF2α-Independent Translation Be the Achilles Heel of Cancer?

Eukaryotic initiation factor eIF2 is a key component of the ternary complex whose role is to deliver initiator tRNA into the ribosome. A variety of stimuli, both physiologic and pathophysiologic activate eIF2 kinases that phosphorylate the α subunit of eIF2, preventing it from forming the ternary complex, thus attenuating cellular protein synthesis. Paradoxically, in cancer cells, the phosphorylation of eIF2α is associated with activation of survival pathways. This review explores the recently emerged novel mechanism of eIF2α-independent translation initiation. This mechanism, which appears to be shared by some RNA viruses and Internal Ribosome Entry Site-containing cellular mRNAs and utilizes auxiliary proteins, such as eIF5B, eIF2D, and MCT-1, is responsible for the selective translation of cancer-associated genes and could represent a weak point amenable to specific targeting for the treatment of cancer.

The mucolipin-2 (TRPML2) ion channel: a tissue-specific protein crucial to normal cell function

The discovery of the TRPML subfamily of ion channels has created an exciting niche in the fields of membrane trafficking, signal transduction, autophagy, and metal homeostasis. The TRPML protein subfamily consists of three members, TRPML1, TRPML2, and TRPML3, which are encoded by MCOLN1, MCOLN2, and MCOLN3 genes, respectively. They are non-selective cation channels with six predicted transmembrane domains and intracellular amino- and carboxyl-terminus regions. They localize to the plasma membrane, endosomes, and lysosomes of cells. TRPML1 is associated with the human lysosomal storage disease known as mucolipidosis type IV (MLIV), but TRPML2 and TRPML3 have not been linked with a human disease. Although TRPML1 is expressed in many tissues, TRPML3 is expressed in a varied but limited set of tissues, while TRPML2 has a more limited expression pattern where it is mostly detected in lymphoid and myeloid tissues. This review focuses on TRPML2 because it appears to play an important, yet unrecognized role in the immune system. While the evidence has been mostly indirect, we present and discuss relevant data that strengthen the connection of TRPML2 with cellular immunity. We also discuss the functional redundancy between the TRPML proteins, and how such features could be exploited as a potential therapeutic strategy for MLIV disease. We present evidence that TRPML2 expression may complement certain phenotypic alterations in MLIV cells and briefly examine the challenges of functional complementation. In conclusion, the function of TRPML2 still remains obscure, but emerging data show that it may serve a critical role in immune cell development and inflammatory responses.

Integrated analysis of miRNA, gene, and pathway regulatory networks in hepatic cancer stem cells

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. HCC has a poor prognosis associated with tumor recurrence and drug resistance, which has been attributed to the existence of hepatic cancer stem cells (HCSCs). However, the characteristics and regulatory mechanisms of HCSCs remain unclear. We therefore established a novel system to enrich HCSCs and we demonstrate that these HCSCs exhibit cancer stem cell properties.

METHODS

We used miRNA and mRNA high-throughput sequencing data sets to determine molecular signatures and regulatory mechanisms in HCSCs. Paired miRNA and gene deep sequencing data in HCSCs versus HCC cells were used to identify candidate biomarkers of HCSCs. Using network analysis, we studied the relationship between miRNA and gene biomarkers, and KEGG pathway enrichment analysis was performed to study the function of candidate biomarkers.

RESULTS

We identified 9 up- and 9 down-regulated miRNAs and 115 up- and 402 down-regulated genes in HCSCs compared with HCC cells. A miRNA-gene network was constructed using 651 miRNA-gene interactions (between 7 up-regulated miRNAs and 274 down-regulated genes), and 103 miRNA-gene interactions (between 9 down-regulated miRNAs and 62 up-regulated genes). Pathway enrichment analysis identified five tumor invasion- and metastasis-related pathways and MAPK signaling associated with HCSCs. We further discovered two novel pathways that likely play a role in the regulation of HCSCs.

CONCLUSIONS

We identified a molecular expression signature and pathway regulatory mechanisms in HCSCs with potential diagnostic and therapeutic value.

The MS4A family: counting past 1, 2 and 3

The MS4A (membrane-spanning 4-domain family, subfamily A) family of proteins contains some well-known members including MS4A1 (CD20), MS4A2 (FcɛRIβ) and MS4A3 (HTm4). These three MS4A family members are expressed on the cell surface of specific leukocyte subsets and have been well characterized as having key roles in regulating cell activation, growth and development. However, beyond MS4A1-3 there are a large number of related molecules (18 to date in humans) where our understanding of their biological roles is at a relatively nascent stage. This review examines the larger MS4A family focusing on their structure, expression, regulation and characterized and/or emerging biological roles. Our own work on one family member MS4A8B, and its possible role in epithelial cell regulation, is also highlighted.

Cancer/testis antigen HCA587-derived long peptide vaccine generates potent immunologic responses and antitumor effects in mouse model

The cancer/testis antigen HCA587 (also known as MAGE-C2), one of the most immunogenic tumor antigens, is overexpressed in a wide spectrum of malignant tumors and can serve as a target for immunotherapy. In this study, we synthesized 14 overlapping (25-35 amino acids) long peptides representing the sequence of the most immunogenic part of the HCA587 protein and evaluated the antigen-specific immune responses and antitumor effects generated by immunization with the synthetic long peptide (SLP) vaccine in a mouse model. HCA587 SLPs in combination with adjuvants CFA and CpG ODN induced potent T-cell responses, which were dominated by type 1 cytokine IFN-γ-producing CD4(+) T cells as measured by ELISPOT and intracellular cytokine staining assay. Moreover, HCA587 SLP vaccination conferred protection against challenge with HCA587-expressing B16 melanoma in a therapeutic setting. Our findings may provide a scientific basis for the use of HCA587-derived long overlapping peptide vaccine for the treatment of patients with cancer in future clinical trials.

CHP2 gene expression and quantitation in Egyptian patients with acute leukemia

AIM

CHP2 (calcineurin B homologous protein 2) is identified as a tumor-associated antigen highly expressed in different malignancies. It plays a critical role in cancer cell development, proliferation, motility and survival. It is suggested that the human tumor related gene CHP2 expression in leukemia primary cells and leukemia cell lines significantly increase, which may play an important role in growth process of leukemia cells.

METHODS

In this study, the expression of CHP2 gene was analyzed in 10 normal healthy controls and 40 patients with de novo acute leukemia (20 AML and 20 ALL). CHP2 expression was analyzed using a real-time quantitative reverse-transcriptase polymerase chain reaction (RTQ-PCR) to investigate a possible relation, association or correlation with the clinical features of AL (acute leukemia) at diagnosis, such as age, gender, lineage, HB, TLC, platelet count, BM blast cell infiltration and risk group.

RESULTS

CHP2 was highly expressed in 13/40 AL studied patients (7/20 AML and 6/20 ALL) with mean expression level of 2.7 while it was not expressed in any of the controls.

CONCLUSIONS

Many studies suggest that CHP2 expression is a novel prognostic marker in AL and thus needs to be incorporated into the patient stratification and treatment protocols. In addition, a quarter of AL patients fail therapy and novel treatments that are focused on undermining specifically the leukemic process are needed urgently.

Exchange factor EFA6R requires C-terminal targeting to the plasma membrane to promote cytoskeletal rearrangement through the activation of ADP-ribosylation factor 6 (ARF6)

ADP-ribosylation factor 6 (ARF6) small GTPase regulates membrane trafficking and cytoskeleton rearrangements at the plasma membrane (PM) by cycling between the GTP-bound active and GDP-bound inactive conformations. Guanine nucleotide exchange factors (GEFs) activate ARF6. The exchange factor for ARF6 (EFA6) R has been identified as a biomarker for ovarian cancer. EFA6R shares the catalytic Sec7, pleckstrin homology (PH), and coiled coil (CC) domains of the other EFA6 family GEFs. Here we report the functional characterization of EFA6R. Endogenous EFA6R was present in the plasma membrane fraction. The exogenously expressed FLAG- and GFP-tagged EFA6R were targeted to the PM. In vitro, GFP-EFA6R associated weakly but preferentially with phosphatidylinositol 4,5-bisphosphate (PIP₂) through the PH domain. EFA6R required both its PH and CC domains localized at the C terminus to target the PM. Consistent with this, EFA6R lacking the CC domain (EFA6RΔCC) was released from the PM into the cytosol upon PIP₂ depletion, whereas EFA6R release from the PM required both PIP₂ depletion and actin destabilization. These results suggest that the dual targeting via the PH and CC domains is important for the PM localization of EFA6R. EFA6R specifically catalyzed the GTP loading of ARF6 in mammalian cells. Moreover, EFA6R regulated ARF6 localization and thereby actin stress fiber loss. The GEF activity of EFA6R was dependent on the presence of the Sec7 domain. The PH and CC domains were also required for the in vivo GEF activity of EFA6R but could be functionally replaced by the CAAX motif of K-Ras, suggesting a role for these domains in the membrane targeting of EFA6R.

Tls1 regulates splicing of shelterin components to control telomeric heterochromatin assembly and telomere length

Heterochromatin preferentially forms at repetitive DNA elements through RNAi-mediated targeting of histone-modifying enzymes. It was proposed that splicing factors interact with the RNAi machinery or regulate the splicing of repeat transcripts to directly participate in heterochromatin assembly. Here, by screening the fission yeast deletion library, we comprehensively identified factors required for telomeric heterochromatin assembly, including a novel gene tls1+. Purification of Tls1 and mass spectrometry analysis of its interacting proteins show that Tls1 associates with the spliceosome subunit Brr2. RNA sequencing analysis shows that the splicing of a subset of mRNAs are affected in tls1Δ cells, including mRNAs of shelterin components rap1+ and poz1+. Importantly, replacing rap1+ and poz1+ with their cDNAs significantly alleviated heterochromatin defects of tls1Δ cells, suggesting that the missplicing of shelterin components is the cause of such defects, and that splicing factors regulate telomeric heterochromatin through the proper splicing of heterochromatin factors. In addition to its role in telomeric heterochromatin assembly, Tls1-mediated splicing of shelterin mRNAs also regulates telomere length. Given that its human homologue C9ORF78 also associates with the spliceosome and is overexpressed in multiple cancer cell lines, our results suggest that C9ORF78 overexpression might alter the proper splicing of genes during cancer progression.