Involvement of X-chromosome Reactivation in Augmenting Cancer Testis Antigens Expression:A Hypothesis

Cancer testis antigens(CTAs)are attractive targets for tumor immunotherapy because of their tumor-specific expression.Since more than half of confirmed CTAs are located on the X-chromosome,we asked whether there is a link between CTA expression and X-chromosomes.Recent reports have shown that reactivation of the inactive X-chromosome,known as X-chromosome reactivation(XCR),a unique phenomenon that exists in many high-risk tumors in women,can transform the expression of many X-linked genes from monoallelic to biallelic.In this review,we discuss the link between CTA and XCR with the hopes of providing some novel insights into tumor biology.

Cancer-testis Antigen OY-TES-1 Expression and Immunogenicity in Hepatocellular Carcinoma

Summary:Cancer testis(CT)antigens have received particular attention in cancer immunotherapy.OY-TES-1 is a member of CT antigens.This study was to evaluate OY-TES-1 expression and immunogenicity in hepatocelluar carcinoma(HCC).OY-TES-1 mRNA expression was detected in 56 HCC tissues and 5 normal liver tissues by reverse transcriptase PCR(RT-PCR).Of the 56 cases of HCC tissues tested,37 cases had tumor and matched adjacent non-cancer tissues and were subjected to both RT-PCR and quantitative real-time PCR.OY-TES-1 protein was subsequently observed on a panel of tissue microarrays.Sera from patients were tested for OY-TES-1 antibody by ELISA.To identify OY-TES-1 capable of inducing cellular immune response,OY-TES-1 protein was used to sensitize dentritic cells and the cytotoxicity effect was measured in vitro.The results showed that OY-TES-1 mRNA was highly expressed in 41 of the 56(73.21%)HCC tissues,whereas none in 5 normal liver tissues.OY-TES-1 mRNA was frequently expressed not only in HCC tissues(72.97%,27/37),but also in paired adjacent non-cancer tissues(64.86%,24/37).But the mean expression level of OY-TES-1 mRNA in HCC tissues was significantly higher than that in adjacent non-cancer tissues(0.76854 vs.0.09834,P=0.021).Immunohistochemistry showed that OY-TES-1 protein expression was detected in 6 of the 49 cases of HCC tissues,and absent in 9 cases of normal liver and 6 cases of cirrhosis tissues.Seropositivity was detected in 10 of the 45 HCC patients,but not detected in 17 cirrhosis patients and 76 healthy donors.The specific cytotoxic T cells elicited by OY-TES-1 could kill HLA-A2^+HCC cell line which expressed OY-TES-1.The target lysis was mainly HLA class I-dependent and could be blocked by antibodies against monomorphic HLA class I but not HLA class II molecule.In summary,OY-TES-1 expression is upregulated in HCC tissues and can be recognized by humoral and cellular responses,which suggests that OY-TES-1 is an attractive target for tumor immunotherapy in HCC.

Demethylating agent decitabine induces autologous cancer testis antigen specific cytotoxic T lymphocytes in vivo

Background Cancer testis antigens （CTAs） are a novel group of tumor associated antigens.Demethylating agent decitabine was reported to be able to up-regulate CTAs through its hypomethylation mechanism,thus enhance the immunogenicity of leukemia cells.However,few researches have ever focused on the questions that whether this immunostimulatory effect of decitabine could induce autologous CTA specific cytotoxic T lymphocytes （CTLs） in vivo,and if so,whether this effect contributes to disease control.In this study,we aimed to show that decitabine could induce specific autologous CTLs against some mouse CTAs in leukemia cells in vitro and in vivo.Methods Several mouse CTAs were screened by RT-PCR.CTL specific to one of the CTAs named P1A was detected and sorted by P1A specific dimer by flow cytometry.The activity of specific CTLs was measured by real time RT-PCR.Results We firstly screened expression of some CTAs in mouse leukemia cells before and after decitabine treatment and found that decitabine treatment did up-regulate expression of many CTAs.Then we measured the CTLs＇ activity specific to a mouse CTA P1A in vivo and showed that this activity increased after decitabine treatment.Finally,we sorted these in vivo induced P1A specific CTLs by flow cytometry and demonstrated their cytotoxicity against decitabine treated leukemia cells.Conclusions Our study showed the autologous immune response induced by decitabine in vivo.And more importantly,we firstly proved that this response may contribute to disease control.We believe that this immunostimulatory effect is another anti-cancer mechanism of decitabine,and this special effect would inspire new applications of decitabine in the field of leukemia treatment in the future.

Cancer/testis antigens： novel tools for discerning aggressive and non-aggressive prostate cancer

The introduction of serum prostate-specific antigen （PSA） in the 1980s has dramatically altered and benefited the initial diagnosis of prostate cancer. However, the widespread use of PSA testing has resulted in overdetection and overtreatment of potentially indolent disease. Thus, a clinical dilemma today in the management of prostate cancer is to discern men with aggressive disease who need definitive treatment from men whose disease are not lethal. Although several serum and tissue biomarkers have been evaluated during the past decade, improved markers are still needed to enhance the accuracy, with which patients at risk can be discerned and treated more aggressively. The cancer/testis antigens （CTAs） are a group of proteins that are restricted to the testis in the normal adult, but are aberrantly expressed in several types of cancers. Because of their restricted expression pattern, the CTAs represent attractive biomarker candidates for cancer diagnosis/prognosis. Furthermore, several studies to date have reported the differential expression of CTAs in prostate cancer. Here, we review recent developments that demonstrate the potential of the CTAs as biomarkers to discern the a^ressive Dhenotvoe of orostate cancer.

Cancer/testis antigen, Kita-Kyushu lung cancer antigen-1 and ABCD stratification for diagnosing gastric cancers

BACKGROUND The ABCD stratification[combination of serum pepsinogen(PG)levels and titers of antibody(immunoglobulin G,IgG)against Helicobacter pylori(H.pylori)]is effective for the classification of individuals at risk of developing gastric cancer(GC).The Kita–Kyushu lung cancer antigen-1(KK-LC-1)is a Cancer/Testis antigen frequently expressed in GC.AIM To evaluate the effectiveness of KK-LC-1 and ABCD stratification in the diagnosis of GC.METHODS We analyzed the gene expression of KK-LC-1 in surgical specimens obtained from GC tumors.The levels of serum PG I/PG II and IgG against H.pylori were measured.According to their serological status,the patients were classified into the four groups of the ABCD stratification.RESULTS Of the 77 examined patients,63(81.8%)expressed KK-LC-1.The IgG titers of H.pylori and PG II were significantly higher in patients expressing KK-LC-1 than those measured in patients not expressing KK-LC-1(P=0.0289 and P=0.0041,respectively).The expression of KK-LC-1 in group C[PG method(+)/H.pylori infection(+)]was as high as 93.9%high.KK-LC-1 was also detected in group A[-/-].CONCLUSION The KK-LC-1 expression in GC was associated with H.pylori infection and atrophic status,so that,KK-LC-1 may be a useful marker for the diagnosis of GC.

Prostate-associated gene 4 （PAGE4）, an intrinsically disordered cancer/testis antigen, is a novel therapeutic target for prostate cancer

Prostate-associated gene 4 （PAGE4） is a remarkably prostate-specific Cancer/Testis Antigen that is highly upregulated in the human fetal prostate and its diseased states but not in the adult normal gland. PAGE4 is an intrinsically disordered protein （IDP） that functions as a stress-response protein to suppress reactive oxygen species as well as prevent DNA damage. In addition, PAGE4 is also a transcriptional regulator that potentiates transactivation by the oncogene c-Jun, c-Jun forms the AP-1 complex by heterodimerizing with members of the Fos family and plays an important role in the development and pathology of the prostate gland, underscoring the importance of the PAGE4/c-Jun interaction. HIPK1, also a component of the stress-response pathway, phosphorylates PAGE4 at T51 which is critical for its transcriptional activity. Phosphorylation induces conformational and dynamic switching in the PAGE4 ensemble leading to a new cellular function. Finally, bioinformatics evidence suggests that the PAGE4 mRNA could be alternatively spliced resulting in four potential isoforms of the polypeptide alluding to the possibility of a range of conformational ensembles with latent functions. Considered together, the data suggest that PAGE4 may represent the first molecular link between stress and prostate cancer （PCa）. Thus, pharmacologically targeting PAGE4 may be a novel opportunity for treating and managing patients with PCa, especially patients with low-risk disease.

FMR1NB Involved in Glioma Tumorigenesis Is a Promising Target for Prognosis and Therapy

Objective:Cancer/testis antigen FMR1NB is aberrantly expressed in various types of cancer,but not in normal tissues except for testis.This study aimed to investigate the expression and functional role of FMR1NB in glioma.Methods:The expression of FMR1NB mRNA and protein was determined using RT-PCR and immunohistochemistry,respectively,in glioma specimens from 83 patients at follow-up.The effects of siRNA-mediated FMR1NB silencing on malignant biological behaviors were evaluated in glioma cell lines Al 72 and U251.Results:FMR1NB mRNA and protein expression was detected in 58.8%(77/131)and 46.34%(57/123)of glioma tissues,respectively.FMR1NB protein was positively correlated with World Health Organization grade and found to be an independent prognostic marker for poor outcome.Knockdown of FMR1NB induced apoptosis and suppressed proliferation,adhesion,migration,and invasion by modulating the expression of cyclin A,CDK2,caspase-3,E-cadherin,and N-cadherin in A172 and U251 cells.Conclusion:Our findings suggest that FMR1NB contributes to the tumorigenesis of glioma cells and may represent a potential prognostic biomarker and an attractive therapeutic target in glioma.

Identification of a TSPY co-expression network associated with DNA hypomethylation and tumor gene expression in somatic cancers

Testis specific protein Y-encoded（TSPY） is a Y-located proto-oncogene predominantly expressed in normal male germ cells and various types of germ cell tumor. Significantly, TSPY is frequently expressed in somatic cancers including liver cancer but not in adjacent normal tissues, suggesting that ectopic TSPY expression could be associated with oncogenesis in non-germ cell cancers. Various studies demonstrated that TSPY expression promotes growth and proliferation in cancer cells; however, its relationship to other oncogenic events in TSPY-positive cancers remains unknown. The present study seeks to correlate TSPY expression with other molecular features in clinical cancer samples, by analyses of RNA-seq transcriptome and DNA methylation data in the Cancer Genome Atlas（TCGA） database. A total of 53 genes,including oncogenic lineage protein 28 homolog B（LIN28B） gene and RNA-binding motif protein Y-linked（RBMY） gene, are identified to be consistently co-expressed with TSPY, and have been collectively designated as the TSPY co-expression network（TCN）. TCN genes were simultaneously activated in subsets of liver hepatocellular carcinoma（30%） and lung adenocarcinoma（10%） regardless of pathological stage, but only minimally in other cancer types. Further analysis revealed that the DNA methylation level was globally lower in the TCN-active than TCN-silent cancers. The specific expression and methylation patterns of TCN genes suggest that they could be useful as biomarkers for the diagnosis,prognosis and clinical management of cancers, especially those for liver and lung cancers, associated with TSPY co-expression network genes.

When MAGE meets RING:insights into biological functions of MAGE proteins

The melanoma antigen(MAGE)family proteins are well known as tumor-specific antigens and comprise more than 60 genes,which share a conserved MAGE homology domain(MHD).Type I MAGEs are highly expressed cancer antigens,and they play an important role in tumorigenesis and cancer cell survival.Recently,several MAGE proteins were identified to interact with RING domain proteins,including a sub-family of E3 ubiquitin ligases.The binding mode between MAGEs and RING proteins was investigated and one important structure of these MAGE-RING complexes was solved:the MAGE-G1-NSE1 complex.Structural and biochemical studies indicated that MAGE proteins could adjust the E3 ubiquitin ligase activity of its cognate RING partner both in vitro and in vivo.However,the underlying mechanism was not fully understood.Here,we review these exciting advances in the studies on MAGE family,suggest potential mechanisms by which MAGEs activate the E3 activity of their binding RING proteins and highlight the anticancer potential of this family proteins.

Discovery of lung squamous carcinoma biomarkers by profiling the plasma peptide with LC/MS/MS

Biomarkers can be used for the screening and clinical diagnosis of cancer,and peptidomics approach has been proven successful in the research of biomarkers.To develop better peptidomic technologies for fast,accurate,and reliable detection of peptides biomarkers for lung cancer,we have improved the procedures of blood collection to minimize the degradation of the blood proteins and optimize the extraction of peptidome peptides from plasma samples based on acetonitrile precipitation associated with size exclusion chromatography（SEC）.Studies show that squamous cell carcinomas are found to express CAGEl,SPAT9 and TEX28 genes at significantly higher rates,and the results suggest that as tumors progress,the level of CAGEl,SPAT9 and TEX28 genes are likely to increase and lead to immunization.This suggests a potentially important therapeutic method for cancer testis-based cancer vaccines.