Identification and Validation of SLC9A2 as A Potential Tumor Suppressor in Colorectal Cancer:Integrating Bioinformatics Analysis with Experimental Confirmation

Objective To uncover the mechanisms underlying the development of colorectal cancer(CRC),we applied bioinformatic analyses to identify key genes and experimentally validated their possible roles in CRC onset and progression.Methods We performed Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis on differentially expressed genes(DEGs),constructed a protein-protein interaction(PPI)network to find the top 10 hub genes,and analyzed their expression in colon adenocarcinoma(COAD)and rectum adenocarcinoma(READ).We also studied the correlation between these genes and immune cell infiltration and prognosis and validated the expression of SLC9A2 in CRC tissues and cell lines using qRT-PCR and Western blotting.Functional experiments were conducted in vitro to investigate the effects of SLC9A2 on tumor growth and metastasis.Results We found 130 DEGs,with 45 up-regulated and 85 down-regulated in CRC.GO analysis indicated that these DEGs were primarily enriched in functions related to the regulation of cellular pH,zymogen granules,and transmembrane transporter activity.KEGG pathway analysis revealed that the DEGs played pivotal roles in pancreatic secretion,rheumatoid arthritis,and the IL-17 signaling pathway.We identified 10 hub genes:CXCL1,SLC26A3,CXCL2,MMP7,MMP1,SLC9A2,SLC4A4,CLCA1,CLCA4,and ZG16.GO enrichment analysis showed that these hub genes were predominantly involved in the positive regulation of transcription.Gene expression analysis revealed that CXCL1,CXCL2,MMP1,and MMP7 were highly expressed in CRC,whereas CLCA1,CLCA4,SLC4A4,SLC9A2,SLC26A3,and ZG16 were expressed at lower levels.Survival analysis revealed that 5 key genes were significantly associated with the prognosis of CRC.Both mRNA and protein expression levels of SLC9A2 were markedly reduced in CRC tissues and cell lines.Importantly,SLC9A2 overexpression in SW480 cells led to a notable inhibition of cell proliferation,migration,and invasion.Western blotting analysis revealed that the expression levels of phosphorylated ERK(p-ERK)and phosphorylated JNK(p-JNK)proteins were significantly increased,whereas there were no significant changes in the expression levels of ERK and JNK following SLC9A2 overexpression.Correlation analysis indicated a potential link between SLC9A2 expression and the MAPK signaling pathway.Conclusion Our study suggests that SLC9A2 acts as a tumor suppressor through the MAPK pathway and could be a potential target for CRC diagnosis and therapy.

GSPT1 Functions as a Tumor Promoter in Human Liver Cancer

Objective This study analyzed the role of G1 to S phase transition 1 protein(GSPT1)in promoting progression of liver cancer cells.Methods A bioinformatics database was used to analyze the expression levels of GSPT1 in liver cancer tissues and the prognosis of patients.Subsequently,Western blotting and quantitative PCR were used to verify the expression levels of GSPT1 between normal hepatocytes and hepatoma cells.We used a CRISPR/Cas9 system to construct knockouts of GSPT1 in HepG2 and HCCLM9 liver cancer cells.The effect of GSPT1 on liver cancer cell migration and invasion was analyzed using flow cytometry,migration,and tumor formation assays.Results The Cancer Genome Atlas Liver Hepatocellular Carcinoma dataset indicated that GSPT1 expression was upregulated in liver cancer cell lines,and patients with liver cancer had poor prognosis.Knockout of GSPT1 in cells significantly inhibited tumor proliferation,cell migration,and growth in vivo.Conclusion In this study,we found that GSPT1 promotes the migration and invasion of liver cancer cells.

DJ-1 Alters Epirubicin-induced Apoptosis via Modulating Epirubicin-activated Autophagy in Human Gastric Cancer Cells

Epirubicin,which is a conventional chemotherapeutic drug for gastric cancer,has innate and adaptive chemoresistance.Recent studies revealed that epirubicin could induce autophagy as a defensive mechanism in drug resistance of mammary carcinoma.Another study implied that D J-1 may be a chemoresistance-related gene.But the association between D J-1 and drug resistance of epirubicin in gastric cancer is still ambiguous.In the present report,we explored whether and how D J-1 conduced to epirubicin-induced apoptosis in gastric cancer.Epirubicin dose-dependently increased the expression of DJ-1 and induced autophagy.Knockdown of DJ-1 notably enhanced epirubicin-induced cell apoptosis,whereas overexpression of DJ-1 attenuated epirubicin-induced cell apoptosis.Further studies revealed that down-regulation of DJ-1 modulated epirubicin-activated autophagy which augmented epirubicin-induced apoptosis.In conclusion,our results validated that DJ-1 reduced epirubicin-induced apoptosis in gastric cancer cells via modulating epirubicin-activated autophagy.

Expression of Stanniocalcin 2 in Breast Cancer and Its Clinical Sigmiicance

This study aims to explore the expression of stanniocalcin 2(STC2)gene in breast cancer and its clinical significance.Female patients with breast cancer from Zhongnan Hospital of Wuhan University admitted during March 2014 to October 2014 were enrolled in this study.All the tissues used in this experiment included 50 cases of breast cancer tissues and corresponding 50 cases of paracancer normal breast tissues with complete patients'information.The real-time quantitative polymerase chain reaction(qPCR)was applied to detect the expression of STC2 gene in 50 cases of breast cancer and paracancer normal breast tissues.The results showed that the expression level of STC2 gene in 50 cases of breast cancer tissues was significantly higher than that in paracancer normal breast tissues(P<0.001).The expression of STC2 gene was correlated with lymph node metastasis,distant metastasis,TNM stage and histological grade(P<0.001).The expression level of STC2 gene was significantly higher in breast cancer tissues with higher expression of Ki-67(P<0.001).The expression level of STC2 gene was significantly higher in estrogen receptor(ER)positive breast cancer tissues than in ER negative ones(P<0.001).However,different groups of age,pathological type,tumor size,PR expression and human epidermal growth factor receptor-2(HER2)expression did not show significant differences in STC2 expression(P>0.05).In conclusion,the abnormal overexpression of STC2 gene may play a role in the development and progression of breast cancer,and it can be used as an independent metastasis and prognostic factor of breast cancer.In addition,STC2 gene probably promotes the development and metastasis of breast cancer by interacting with estrogen and ER,and it may become a new direction for breast cancer endocrine therapy.

Bioinformatics Analysis and Identification of Potential Genes Associated with Pathogenesis and Prognosis of Gastric Cancer

Objective Gastric cancer(GC)is a deadly cancer and a challenging public health problem globally.This study aimed to analyze potential genes associated with pathogenesis and prognosis of gastric cancer.Methods This work selected the overlapping differentially expressed genes(DEGs)in GC from four datasets,the GSE29272,GSE29998,GSE54129 and GSE118916 Gene Expression Omnibus databases.These DEGs were used to carry out comprehensive bioinformatic analysis to analyze the related functions and pathways enriched,the relative expression levels and immune infiltrates,the prognostic characteristics and the interaction network.Results In total,55 DEGs increased while 98 decreased in their expression levels.For those DEGs with increased expression,they were mostly concentrated on“focal adhesion”and“ECM-receptor interaction”,whereas DEGs with decreased expression were mostly associated with“gastric acid secretion”and“drug metabolism cytochrome P450”.MCODE and ClueGO results were then integrated to screen 10 hub genes,which were FN1,COL1A1,COL3A1,BGN,TIMP1,COL1A2,LUM,VCAN,COL5A2 and SPP1.Survival analysis revealed that higher expression of the ten hub genes significantly predicted lower overall survival of GC patients.TIMP1 was most significantly related to neutrophils,CD8+T cells,as well as dendritic cells,while LUM was most significantly related to macrophages.Conclusion Immunohistochemistry results and functional testing showed that the expression of COL5A2 was elevated in GC and that it might be a key gene in GC tumorigenesis.

Identification of Prognostic Genes for Colon Cancer through Gene Coexpression Network Analysis

Objective:The present study was aimed to identify novel key genes,prognostic biomarkers and molecular pathways implicated in tumorigenesis of colon cancer.Methods:The microarray data GSE41328 containing 10 colon cancer samples and 10 adjacent normal tissues was analyzed to identify 4763 differentially expressed genes.Meanwhile,another microarray data GSE17536 was performed for weighted gene co-expression network analysis(WGCNA).Results:In present study,12 co-expressed gene modules associated with tumor progression were identified for further studies.The red module showed the highest association with pathological stage by Pearson's correlation analysis.Functional enrichment analysis revealed that genes in red module focused on cell division,cell proliferation,cell cycle and metabolic related pathway.Then,a total of 26 key hub genes were identified,and GEPIA database was subsequently selected for validation.Holliday junction-recognizing protein(HJURP)and cell division cycle 25 homolog C(CDC25C)were identified as effective prognosis biomarkers,which were all detrimental to prognosis.Gene set enrichment analyses(GSEA)found the two hub genes were enriched in“oocyte meiosis”,“oocyte maturation that are progesterone-mediated”,“p53 signaling pathway”,and“cell cycle”.Furthermore,the immunohistochemistry and western blotting showed that HJURP was highly expressed in colon cancer tissue.Conclusion:HJURP was identified as a key gene associated with colon cancer progression and prognosis by WGCNA,which might influence the prognosis by regulating cell cycle pathways.

Overexpression of eRF3a Promotes Cell Proliferation and Migration in Liver Cancer

Objective:The eukaryotic release factor 3a(eRF3a),a member of the eukaryotic peptide chain release factor family,is overexpressed in several types of cancer.This study aims to investigate the biological role and mechanism of eRF3a in the progression of liver cancer.