Lecithin-cholesterol acyltransferase is a potential tumor suppressor and predictive marker for hepatocellular carcinoma metastasis

BACKGROUND Hepatocellular carcinoma(HCC)is a major cause of cancer mortality worldwide,and metastasis is the main cause of early recurrence and poor prognosis.However,the mechanism of metastasis remains poorly understood.AIM To determine the possible mechanism affecting HCC metastasis and provide a possible theoretical basis for HCC treatment.METHODS The candidate molecule lecithin-cholesterol acyltransferase(LCAT)was screened by gene microarray and bioinformatics analysis.The expression levels of LCAT in clinical cohort samples was detected by quantitative realtime polymerase chain reaction and western blotting.The proliferation,migration,invasion and tumor-forming ability were measured by Cell Counting Kit-8,Transwell cell migration,invasion,and clonal formation assays,respectively.Tumor formation was detected in nude mice after LCAT gene knockdown or overexpression.The immunohistochemistry for Ki67,E-cadherin,N-cadherin,matrix metalloproteinase 9 and vascular endothelial growth factor were performed in liver tissues to assess the effect of LCAT on HCC.Gene set enrichment analysis(GSEA)on various gene signatures were analyzed with GSEA version 3.0.Three machine-learning algorithms(random forest,support vector machine,and logistic regression)were applied to predict HCC metastasis in The Cancer Genome Atlas and GEO databases.RESULTS LCAT was identified as a novel gene relating to HCC metastasis by using gene microarray in HCC tissues.LCAT was significantly downregulated in HCC tissues,which is correlated with recurrence,metastasis and poor outcome of HCC patients.Functional analysis indicated that LCAT inhibited HCC cell proliferation,migration and invasion both in vitro and in vivo.Clinicopathological data showed that LCAT was negatively associated with HCC size and metastasis(HCC size≤3 cm vs 3-9 cm,P<0.001;3-9 cm vs>9 cm,P<0.01;metastatic-free HCC vs extrahepatic metastatic HCC,P<0.05).LCAT suppressed the growth,migration and invasion of HCC cell lines via PI3K/AKT/mTOR signaling.Our results indicated that the logistic regression model based on LCAT,TNM stage and the serum level of α-fetoprotein in HCC patients could effectively predict high metastatic risk HCC patients.CONCLUSION LCAT is downregulated at translational and protein levels in HCC and might inhibit tumor metastasis via attenuating PI3K/AKT/mTOR signaling.LCAT is a prognostic marker and potential therapeutic target for HCC.

RASAL2 acts as a tumor suppressor in cervical cancer cells

This study was designed to investigate the roles of RASAL2 in cervical cancer(CC).Methods:Fifty-four CC tissues and 33 adjacent tissues were obtained from CC patients admitted to our hospital between March 2012 and June 2014.Real-time polymerase chain reaction and western blotting were performed to analyze the expression of RASAL2 mRNA and protein in these tissues,CC cell lines,and normal cervical cells.Over-expression and silencing of RASAL2 were induced after transfection,and the migration,invasion,and proliferation of the CC cell lines were examined.Results:RASAL2 mRNA and protein expressions were significantly down-regulated in CC tissues and cell lines than in adjacent tissues and normal cervical cells,respectively.While low RASAL2 expression correlated with advanced stage and metastasis of CC,its over-expression significantly inhibited proliferation and metastasis of CC cells and induced apoptosis.Under in vitro conditions,silencing of RASAL2 expression could significantly increase the proliferation,invasion,and migration of CC cells.Conclusion:RASAL2 functioned as a tumor suppressor in CC,and was down-regulated in CC tissue samples and cell lines.

Cloning and Expression Analysis of a Human Putative Tumor Suppressor Gene Homologue from Rice

A gene homologous to the human Putative tumor suppressor gone QM, designated OSQM1, was isolated from rice (Oryza sativa L.) genomic DNA library using through homology screening. It contained 4 exons and 3 introns, encoding a protein of 219 amino acids with 46 basic amino acids, leading to a high isoelectric point of 11.02. Homology search showed that this gene existed in eukaryotes and highly conserved throughout eukaryotes, suggesting an essential role of this gene. Northern Not analysis showed that it was expressed in various rice organs, but at lower level in developing flower and callus tissue than in other vegetative organs. Its expression levels in roots and leaves were influenced by different environmental factors.

Overexpression and mutations of tumor suppressor gene p53 in hepatocellular carcinoma

AIMS To examine the prevalance of p53 mutations in hepatocellular carcinoma (HCC) from Chongqing area and the relationship between the p53 mutations and clinicopathological features of HCC,as well as the risk factors. METHODS The overexpression and point mutations of tumor suppressor gene p53 in 38 cases of HCC were detected by a sensitive antigen retrieval fluid (ARF) immunohistochemical method and polymerase chain re- action(PCR)-restriction fragment length polymorphism (RFLP),and single strand conformation polymorphism (SSCP)-silver staining analysis. RESULTS The results showed that 16 of 38 HCCs had positive p53 protein (42.1%),7 HCCs had p53 mutation at 249 (18.4 % ) and 2 HCCS had point muta- tion within exon 7 other than 249. Among 9 cases of HCC with mutations,8 cases demonstrated positive p53 protein,its coincidental rate was 88.9%. The overexpression and mutations of p53 were significantly related to the differentiation and metastasis of HCCs. The frequency of p53 mutations was consistent with high prevalence of HBV and a moderate aflatoxin B1 (AFB1) exposure in our area. CONCLUSIONS The results suggest that AFB1 acts synergistically with HBV in the generation of p53 mutations. Furthermore,dietary exposure to AFB1 may mainly contribute to the tumor specific mutation at codon 249,while HBV may account for other scattered mutations in HCC.

Paradoxical role of interleukin-33/suppressor of tumorigenicity 2 in colorectal carcinogenesis: Progress and therapeutic potential

Colorectal cancer(CRC)is presently the second most prevalent global mortalityinducing cancer.CRC carcinogenesis is a multifactorial process involving internal genetic mutations and the external environment.In addition,non-neoplastic cell activities within tumor microenvironments for CRC development have been established.However,interleukin(IL)-33,secreted by such cell types,plays a pivotal role in cancer progression due to interaction with cellular constituents within the tumor-inflammation microenvironment.IL-33 belongs to the IL-1 cytokine family and acts as binding attachments for the suppressor of tumorigenicity(ST)2 receptor.Therefore,how to coordinate tumor microenvironment,design and optimize treatment strategies suitable for CRC,based on IL-33/ST2 signal is a challenge.Even though it has established influences upon immunitylinked conditions,IL-33 effects on CRC progression and prevention and related mechanisms are still controversial.Our review depicts controversial activities for IL-33/ST2 within carcinogenesis and cancer prevention.Moreover,IL-33/ST2 signaling is a potential therapeutic target for CRC.

Characterization of six tumorsuppressor genes and microsatellite instability in hepatocellular carcinomain southern African blacks

AIM To analyse cumulative loss of heterozygosity (LOH) of chromosomal regions and tumor suppressor genes in hepatocellular carcinomas (HCCs) from 20 southern African blacks. METHODS p53, RB1, BRCA1, BRCA2, WT1 and E cadherin genes were analysed for LOH, and p53 gene was also analysed for the codon 249 mutation, in tumor and adjacent non tumorous liver tissues using molecular techniques and 10 polymorphic microsatellite markers. RESULTS p53 codon 249 mutation was found in 25% of the subjects, as was expected, because many patients were from Mozambique, a country with high aflatoxin B 1 exposure. LOH was found at the RB1, BRCA2 and WT1 loci in 20%(4/*!20) of the HCCs, supporting a possible role of these genes in HCC. No LOH was evident in any of the remaining genes. Reports of mutations of p53 and RB1 genes in combination, described in other populations, were not confirmed in this study. Change in microsatellite repeat number was noted at 9/*!10 microsatellite loci in different HCCs, and changes at two or more loci were detected in 15%(3/*!20) of subjects. CONCLUSION We propose that microsatellite/genomic instability may play a role in the pathogenesis of a subset of HCCs in black Africans.

Tumor suppressor role of mi R-133a in gastric cancer by repressing IGF1R

AIM:To investigate the function and mechanism of mi R-133a in gastric cancer(GC)and its relationship with clinicopathological characteristics of GC.METHODS:A total of 105 GC patients who underwent surgical resection as primary treatment were selected for this study.Real-time quantitative reverse transcriptase polymerase chain(q RT-PCR)was used to examine the expression levels of mi R-133a in human GC and adjacent non-tumor tissues,as well as in GC cell lines(SGC-7901,BGC-823,MGC-803,and AGS)and a human gastric mucosal epithelial cell line(GES-1).The biological role of mi RNA(mi R)-133a was assessed in the GC cell lines using MTT,apoptosis,migration and invasion,and colony formation assays,and xenograft tumorigenesis.q RT-PCR and western blot analyses were used to evaluate the potential target gene expression of mi R-133a.Pearson’s correlation was calculated to evaluate the correlation between mi R-133a and insulinlike growth factor 1 receptor(IGF1R)expression.The regulation of IGF1R by mi R-133a was verified using the luciferase reporter assay.RESULTS:In 80%of the 105 GC patients,the mean expression of mi R-133a was significantly downregulated in tumor tissues compared with adjacent normal tissues(1.215±0.1477 vs 3.093±0.4104,P<0.0001).Downregulation of mi R-133a was significantly correlated with the degree of differentiation(P=0.01),local invasion(P=0.001)and TNM stage(P=0.02)in GC patients.Compared with a control construct,forced expression of mi R-133a in GC cell lines inhibited proliferation(0.4787±0.0219 vs 0.7050±0.0147,P=0.0013 in SGC-7901 cells;and 0.5448±0.0085vs 0.7270±0.0084,P=0.001 in MGC-803 cells);migration(0.6333±0.0233 vs 1.037±0.0584,P=0.003 in SGC-7901 cells;0.6126±0.0311 vs 1.024±0.0456,P=0.0017 in MGC-803 cells);and invasion(0.613±0.0399 vs 1.033±0.0278,P=0.0013 in SGC-7901 cells;0.7433±0.0221 vs 1.017±0.0311,P=0.002 in MGC-803 cells).It also induced apoptosis(18.19%±0.2483%vs 5.887%±0.3837%,P<0.0001 in SGC-7901 cells;22.69%±0.7846%vs9.347%±0.3012%,P<0.0001 in MGC-803 cells).Furthermore,mi R-133a inhibited tumor growth and xenograft tumorigenesis of SGC-7901 cells in vivo.In addition,we identified IGF1R as a regulatory target of mi R-133a in GC.CONCLUSION:This study suggests that mi R-133a is downregulated in GC and functions as a tumor suppressor in vitro and in vivo partly by repressing IGF1R.

Alteration of tumor suppressor gene p16 and Rb in gastric cancinogesis

IM To study the alterations of tumor suppressor gene p16 and Rb in the carcinogenesis of the stomach. METHODS Different mucosal biopsies were endoscopically obtained, all samples were immediately fixed with 10% buffered formalin, embedded with paraffin and sectioned serielly. Alterations of p16 and Rb protein in 12 cases of superficial gastritis, 15 atrophic gastritis, 20 atypical hyperplasia and 40 cancerous tissues were detected by the immunohistochemical method (ABC). RESULTS Different degrees of nuclear immunostaining of p16 and Rb occurred on gastric epithelium in different stages of lesions. With the lesions progressing, the positive immunostaining rate of p16 protein had a decreasing tendency (833%→733%→300%→275%), and on the other hand, that of Rb protein had an increasing tendency (250%→467%→600%→675%). A negative correlationship was found between these two parameters in the gastric cancer. Of 40 cases of gastric cancer, a negative relationship was observed in 20 cases. In comparison with both positive (9 cases) and both negative tissues (11 cases), there was a significant difference (500%,225%,275%) (P<005).CONCLUSION Abnormal expression of p16 and Rb plays an important role in gastric carcinogenesis.

Hepatocellular carcinoma mouse models:Hepatitis B virusassociatedhepatocarcinogenesis and haploinsufficienttumor suppressor genes

The multifactorial and multistage pathogenesis of hepatocellular carcinoma(HCC)has fascinated a wide spectrum of scientists for decades.While a number of major risk factors have been identified,their mechanistic roles in hepatocarcinogenesis still need to be elucidated.Many tumor suppressor genes(TSGs)have been identified as being involved in HCC.These TSGs can be classified into two groups depending on the situation with respect to allelic mutation/loss in the tumors:the recessive TSGs with two required mutated alleles and the haploinsufficient TSGs with one required mutated allele.Hepatitis B virus(HBV)is one of the most important risk factors associated with HCC.Although mice cannot be infected with HBV due to the narrow host range of HBV and the lack of a proper receptor,one advantage of mouse models for HBV/HCC research is the numerous and powerfulgenetic tools that help investigate the phenotypic effects of viral proteins and allow the dissection of the dose-dependent action of TSGs.Here,we mainly focus on the application of mouse models in relation to HBV-associated HCC and on TSGs that act either in a recessive or in a haploinsufficient manner.Discoveries obtained using mouse models will have a great impact on HCC translational medicine.

Inactivation of RASSF1A, the tumor suppressor gene at 3p21.3 in extrahepatic cholangiocarcinoma

AIM: To evaluate the genetic and epigenetic inactivation mechanism of the RASSF1A tumor suppressor gene at 3p21.3 in extrahepatic cholangiocarcinoma. METHODS: RT-PCR was used to investigate the transcriptional expressing and re-expression of RASSFIA. RASSFIA mutation was analyzed with SSCP and selective sequencing. PCR was performed to detect the loss of heterozygosity (LOH) at the region of chromosome 3p21.3. Genomic DNA were modificated bisulfite and the frequency of methylation of CpG islands in RASSFIA promoter were evaluated by methylation specific PCR (MS-PCR). RESULTS: In all 48 samples and one cell lines of extrahepatic cholangiocarcinoma, the RASSFIA mutation is rare (6.12%, 3/49), 33 samples (68.75%) and QBC-939 cell lines (X2= 14.270, P= 0.001<0.01) showed RASSFIA express inactivation with LOH at microsatellite loci D3S4604. Among these 33 samples and QBC-939, 28 of 33 (84.85%) tumor samples and 1 cell lines were methylated for majority of 16 CpGs, the average frequency is 73.42%. CONCLUSION: The data we present suggest that RASSFIA which we have been searching for at 3p21.3 may be one of the key tumor suppressor gene and play an important role in the pathogenesis of extrahepatic cholangiocarcinoma, and the promoter methylation and allelic loss are the major mechanism for inactivation of RASSFIA.

Tumor suppressor and hepatocellular carcinoma

A few signaling pathways are driving the growth of hepatocellular carcinoma.Each of these pathways possesses negative regulators.These enzymes,which normally suppress unchecked cell proliferation,are circumvented in the oncogenic process,either the overactivity of oncogenes is sufficient to annihilate the activity of tumor suppressors or tumor suppressors have been rendered ineffective.The loss of several key tumor suppressors has been described in hepatocellular carcinoma.Here,we systematically review the evidence implicating tumor suppressors in the development of hepatocellular carcinoma.

mi R-382 functions as a tumor suppressor against esophageal squamous cell carcinoma

AIM To explore the effect of miR-382 on esophageal squamous cell carcinoma (ESCC) in vitro and its possible molecular mechanism. METHODS Eca 109 cells derived from human ESCC and Het-1A cells derived from human normal esophageal epithelium were used. Lentivirus-mediated miR-382 was overexpressed in Eca109 cells. The effect of miR-382 on cell proliferation was evaluated by MTT and colony formation assay. For cell cycle analysis, cells were fixed and stained for 30 min with propidium iodide (PI) staining buffer containing 10 mg/mL PI and 100 mg/mL RNase A, and analyzed by BD FACSCalibur (TM) flow cytometer. For cell apoptosis assay, cells were stained with an Annexin V-FITC/PI Apoptosis Detection Kit according to the manufacturer's instructions and analyzed by a dual-laser flow cytometer. Cell invasion and migration abilities were determined through use of transwell chambers, non-coated or pre-coated with matrigel. Levels of proteins related to cell growth and migration were examined by western blotting. RESULTS Endogenous miR-382 was down-regulated in Eca109 cells compared with Het-1A. Introduction of miR-382 not only significantly inhibited proliferation and colony formation, but also arrested cell cycle at the G2/M phase, as well as promoted apoptosis and autophagy in Eca109 cells. Migration, invasion and epithelial-mesenchymal transition of Eca109 cells were suppressed by overexpressing miR-382. Western blotting results showed that miR-382 inhibited the phosphorylation of mTOR and 4E-BP1. CONCLUSION miR-382 functions as a tumor suppressor against ESCC development and metastasis, and could be considered as a potential drug source for the treatment of ESCC patients.

PTEN： a default gate-keeping tumor suppressor with a versatile tail

The tumor suppressor PTEN controls a variety of biological processes including cell proliferation, growth, migration, and death. As a master cellular regulator, PTEN itself is also subjected to deliberated regulation to ensure its proper function. Defects in PTEN regulation have a profound impact on carcinogenesis. In this review, we briefly discuss recent advances concerning PTEN regulation and how such knowledge facilitates our understanding and further exploration of PTEN biology. The carboxyl-tail of PTEN, which appears to be associated with multiple types of posttranslational regulation, will be under detailed scrutiny. Further, a comparative analysis of PTEN and p53 suggests while p53 needs to be activated to suppress tumorigenesis （a dormant gatekeeper）, PTEN is probably a constitutive surveillant against cancer development, thus a default gatekeeper.

Aberrant Methylation in CpG Islands of pl5 and pl6 Tumor Suppressor Genes in Pancreatic Cancer Tissue

Objective： To detect the aberrant methylation patterns in the CpG islands of p16 and p15 tumor suppressor genes, and to analyze its correlation with pancreatic carcinogenesis and with clinicopathological characteristics of patients with pancreatic cancer （PC）. Methods： The methylation-specific polymerase chain reaction （MSP） method was used to monitor methylation patterns in the CpG islands of p15 and p16 genes from 29 cases of PC and 3 cases of chronic pancreatitis （CP） paraffin-embedded tissue, as well as 2 cases of normal liver tissues and 12 cases of normal blood samples. Results： p15 and p16 genes were detected to show unmethylation patterns and no amplification using methylation-specific primers in control group. The aberrant methylation rates of p16 in carcinoma tissue and adjacent noncarcinoma tissue were 37.9% （11 of 29 cases） and 34.5% （10 of 29 cases） respectively. Of the 11 aberrant methylated samples, 5 showed complete methylation and 6 hemimethylation. The methylation rates of p15 gene in carcinoma tissue and adjacent noncarcinoma tissue were 27.5% （8/29） and 24.4% （7/29） respectively. Of the 8 aberrant methylated samples, 3 showed complete methylation and 5 hemimethylation. In 6 PC samples, aberrant methylation in CpG islands of both p15 and p16 genes existed simultaneously. The aberrant methylation patterns in CpG islands of p15 and p16 genes had no close correlation with the clinicopathological characteristics （age, sex, smoking, volume of primary tumor, differentiation, clinical stage and histological classification） of the patients with PC （P〉0.05）. Conclusion： The aberrant methylation in CpG islands of p15 and p16 genes could be regarded as an early molecular event in PC and had no close correlation with the clinicopathological characteristics of the patients with PC.

Science Letters:IGFBP7 plays a potential tumor suppressor role against colorectal carcinogenesis with its expression associated with DNA hypomethylation of exon 1

Insulin-like growth factor binding-protein-7 （IGFBP7） was obtained from our previous colonic adenocarcinoma （CRC） and normal mucosa suppression subtraction hybridization （SSH） cDNA libraries. By RT-PCR and immunohistochemistry, we found that IGFBP7 was overexpressed in CRC tissue compared to normal tissue. However, our in vitro experiments performed in 10 CRC cell lines showed that IGFBP7 expressed only in SW480 and Caco2 cell lines, which implied an underlying reversible regulatory mechanism. Using methylation-specific PCR （MSP） and bisulfite sodium PCR （BSP）, we found that its expression was associated with DNA hypomethylation of exonl. This was further supported by the in vitro study which showed restored IGFBP7 expression after demethylation agent 5-aza-2＇-deoxycytidine treatment. Correlation analysis between IGFBP7 expression and prognosis indicated that overexpression of IGFBP7 in CRC tissue correlated with favourable survival. Investigation of the functional role of IGFBP7 through transfection studies showed that IGFBP7 protein could inhibit growth rate, decrease colony formation activity, and induce apoptosis in RKO and SW620 cells, suggesting it a potential tumor suppressor protein in colorectal carcinogenesis. In conclusion, our study clearly demonstrated that IGFBP7 plays a potential tumor suppressor role against colorectal carcinogenesis and its expression is associated with DNA hypomethylation of exon 1.

Relationship between hepatitis B virus associated primary hepatocellular carcinoma and alteration of tumor suppressor gene p53

Objective: To explore the changes and significance of tumor suppressor gene p53 in primary hepatocellu-lar carcinoma (PHC ) with hepatitis B virus (HBV ) infection. Methods: Tumor tissues and surrounding nontumortissues of sixteen PHC cases were studied by Southern hybridization to detect the state of HBV-DNA in tissues, byimmunohistochemical staining to determine HBsAg, HBxAg and p53 protein, and by PCR directed sequencing toanalyse the point mutation of p53 gene exons 5 to 8. Results: Among the 16 cases. 13 cases were HBV-DNA posi-tive, 10 tumor cases and 13 nontumor tissues cases HBxAg positive, and 9 cases posltive for p53 protein. The se-quencing of p53 gene point mutation was found in 5 cases, only one of which was sited at codon 249 G to T. Con-clusion: The mutation of p53 gene codon 249 is infrequent in HBV related PHC,indicating the accumulation of p53protein in cells may be associated with expression of HBxAg. HBxAg binding to p53 protein and inactivation of p53function play important roles in the development of PHC.

Hypermethylation of tumor suppressor and tumor-related genes in neoplastic and non-neoplastic gastric epithelia

A number of tumor suppressor and tumor-related genes exhibit promoter hypermethylation with resultant gene silencing in human cancers.The frequencies of methylation differ among genes and genomic regions within CpG islands in different tissue types.Hypermethylation initially occurs at the edge of CpG islands and spreads to the transcription start site before ultimately shutting down gene expression.When the degree of methylation was quantitatively evaluated in neoplastic and non-neoplastic gastric epithelia using DNA microarray analysis,highlevel methylation around the transcription start site appeared to be a tumor-specific phenomenon,although multiple tumor suppressor genes became increasingly methylated with patient age in non-neoplastic gastric epithelia.Quantitative analysis of DNA methylation is a promising method for both cancer diagnosis and risk assessment.

Inactivation of the tumor suppressor Krüppel-like factor 6 (KLF6) by mutation or decreased expression in hepatocellular carcinomas

Background and aim： The Krueppel-like transcription factor KLF6 is a novel tumor-suppressor gene. It was inactivated in human prostate cancer and other tumors tissue, as the result of frequent mutation and loss of heterozygosity （LOH）. However, there is no data reporting the levels of KLF6 both mRNA and protein in hepatocellular carcinomas （HCCs）. We therefore detected mutations and expression of KLF6 in HCC tissues and further observed the effect of it on cell growth in HCC cell lines. Methods： We analyzed the exon-2 ofKLF6 gene by direct DNA sequencing, and detected the expression of KLF6 by RT-PCR and Western blot in 23 HCC tissues and corresponding nontumorous tissues. Loss of growth suppressive effect of the HCC-derived KLF6 mutant was characterized by in vitro growth curves plotted, flow cytometry and Western blotting. Results： KLF6 mutations were found in 2 of 23 HCC tissues and one of mutations was missense. Expression ofKLF6 mRNA or protein was down-regulated in 8 （34.7%） or 9 （39.1%） of 23 HCC tissues. Wild-type KLF6 （wtKLF6） inhibited cellular proliferation and prolonged G1 -S transition by inducing the expression of p21WAF 1 following stable transfection into cultured HepG2 cells, but tumor-derived KLF6 mutant （mKLF6） had no effects. Conclusion： Our findings suggest that KLF6 may be involved in pathogenesis of HCC.

Aberrant methylation of the 3q25 tumor suppressor gene PTX3 in human esophageal squamous cell carcinoma

AIM:To identify the novel methylation-silenced gene pentraxin 3(PTX3) in esophageal squamous cell carcinoma(ESCC).METHODS:PTX3 mRNA expression was examined in six human ESCC cell lines,one human immortalized normal esophageal epithelial cell line,primary ESCC tumor tissue,and paired adjacent nontumor tissue using reverse transcription polymerase chain reaction(RTPCR).Semi-quantitative immunohistochemistry was used to examine cellular localisation and protein levels.Methylation specific PCR and bisulphite genomic sequencing were employed to investigate the methylation of the candidate gene.RESULTS:In the majority of ESCC cell lines,we found that PTX3 expression was down-regulated due to gene promoter hypermethylation,which was further confirmed by bisulphite genomic sequencing.Demethylation treatment with 5-aza-2'-deoxycytidine restored PTX3 mRNA expression in ESCC cell lines.Methylation was more common in tumor tissues(85%) than in adjacent nontumor tissues(25%)(P < 0.01).CONCLUSION:PTX3 is down-regulated through promoter hypermethylation in ESCC,and could potentially serve as a biomarker of ESCC.

Identification of a potential tumor suppressor gene, UBL3, in non-small cell lung cancer

Objective: Oncogenes have been shown to be drivers of non-small cell lung cancer(NSCLC), yet the tumor suppressing genes involved in lung carcinogenesis remain to be systematically investigated. This study aimed to identify tumor suppressing ubiquitin pathway genes(UPGs) that were critical to lung tumorigenesis.Methods: The 696 UPGs were silenced by an siRNA screening in NSCLC cells;the potential tumor suppressing UPGs were analyzed, and their clinical significance was investigated.Results: We reported that silencing of 11 UPGs resulted in enhanced proliferation of NSCLC cells, and four UPGs(UBL3, TRIM22, UBE2 G2, and MARCH1) were significantly downregulated in tumor samples compared to that in normal lung tissues and their expression levels were positively associated with overall survival(OS) of NSCLC patients. Among these genes, UBL3 was the most significant one. UBL3 expression was decreased in tumor samples compared to that in paired normal lung tissues in 59/86(68.6%) NSCLCs, was correlated with TNM stage and sex of NSCLC patients, and was significantly higher in non-smoking patients than in smoking patients. Silencing UBL3 accelerated cell proliferation and ectopic expression of UBL3 suppressed NSCLC in vitro and in vivo.Conclusions: These results showed that UBL3 represented a tumor suppressor in NSCLC and may have potential for use in therapeutics and for the prediction of clinical outcome of patients.