泛素特异性蛋白酶53在结直肠癌中的表达及其对HCT116细胞的抑制作用

目的:探讨泛素特异性蛋白酶53(ubiquitin specific peptidase 53,USP53)在结直肠癌组织中的表达水平及其过表达对人结直肠癌HCT116细胞功能的影响.方法:运用Real-time PCR及IHC方法检测结直肠癌及癌旁组织中USP53的表达情况;利用UCSC CANCER BROWSER提供的TCGA数据库,检测USP53 mRNA表达水平与临床特征及预后的关系;HCT116细胞中瞬时过表达USP53,利用CCK-8及克隆形成实验检测HCT116细胞增殖变化.结果:免疫组化结果显示,USP53在癌旁组织中的表达显著高于肿瘤组织[91.67％(44/48) vs 18.75％ (9/48),P＜0.01].癌旁组织中USP53 mRNA水平也高于癌组织[(0.85±0.32) vs (0.46 ±0.27),P＜0.05].组织中USP53 mRNA表达水平与预后有关,表达越低预后越差(P＜0.05).过表达USP53后,细胞克隆形成数目显著下降[(123 ±27.22) vs (338±55.24)个,P＜0.01];CCK-8实验结果显示,肿瘤细胞增殖受到显著抑制[(0.14±0.01) vs (0.18±0.04),P＜0.05;(0.23±0.01)vs(0.32±0.01),P＜0.01;(0.45±0.03) vs (0.80±0.05),P＜0.01;(0.83 ±0.03)vs (1.18±0.10),P＜0.01].结论:USP53在结直肠癌中表达下调与不良预后相关,USP53可抑制肿瘤细胞增殖,提示USP53可作为诊断及治疗结直肠癌的新靶标.     

PUS7 promotes the proliferation of colorectal cancer cells by directly stabilizing SIRT1 to activate the Wnt/β-catenin pathway

Pseudouridine synthase 7 (PUS7) may play key roles in cancer development. However, few studies have been conducted in this area. In the present study, we explored the function and potential mechanisms of PUS7 in colorectal cancer (CRC) progression. We found that PUS7 had higher expression in CRC tissues and cell lines. Clinically, high expression of PUS7 was associated with an unfavorable prognosis for CRC patients. Functionally, knockdown of PUS7 suppressed the proliferation of CRC cells in vitro and inhibited tumorigenicity in vivo. Mechanistically, RNA sequencing and coimmunoprecipitation (Co-IP) indicated that PUS7 exhibited oncogenic functions through the interaction of Sirtuin 1 (SIRT1) and activated the Wnt/β-catenin signaling pathway. Thus, our findings suggest that PUS7 promotes the proliferation of CRC cells by directly stabilizing SIRT1 to activate the Wnt/β-catenin pathway.     

TYMS-TM4SF4 axis promotes the progression of colorectal cancer by EMT and upregulating stem cell marker

Background: The expression of thymidylate synthase (TYMS) is significantly up-regulated in various cancers and associated with the poor prognosis of patients. However, the role of TYMS in the progression of colorectal cancer (CRC) is unclear. Methods: Cell function assay, biology information analysis, and RNA sequencing were used to investigate the role of TYMS in the progression of CRC and underlining molecular mechanism. SPSS22.0 statistical software and GraphPad Prism 5 (Graphpad software) were used for statistical analysis. Results: Our results showed that TYMS expression was higher in CRC tissues than that in non-tumor colorectal mucosa tissues. TYMS knockdown inhibited the proliferation, migration and invasion of HCT116 and HT29 cells, and the spheroid formation of HCT116 cells. The underling mechanism demonstrated that TYMS promoted the progression of CRC by regulating EMT-related proteins including E-cadherin, Vimentin, MMP-9 and stem cell biomarkers including CD133 and CD44. Furthermore, DEG sequencing showed that TYMS knockdown enriched the pathways of metastasis and metabolism by GO and KEGG analysis. We identified TM4SF4 was the downstream target of TYMS in CRC cells. TM4SF4 overexpression increased migration and invasion of CRC cells by regulating EMT and CD133 expression. Conclusions: Our findings suggest that TYMS-TM4SF4 axis may promote the progression of CRC by EMT and upregulating stem cell markers.     

ZNF217 is Overexpressed and Enhances Cell Migration and Invasion in Colorectal Carcinoma

Background: To investigate the expression and clinical significance of zinc finger protein 217 (ZNF217)in human colorectal carcinoma (CRC). Materials and Methods: The expression of ZNF217 in 60 CRCtissues and matched tumor adjacent tissues, collected between January 2013 and June 2014, was assessedimmunohistochemically. The relationship between the expression of ZNF217 and clinicopathlogical features wasanalyzed by Pearson chi-square test. In addition, siRNA was used to down-regulate the expression of ZNF217 inCRC cells. The effects of ZNF217 for cell migration and invasion were measured by wound healing assay andtranswell assay, respectively. Results: The expression level of ZNF217 was significantly higher in CRC tissuesthan in tumor adjacent tissues (p<0.05), positively correlating with tumor size, lymphatic metastasis and advancedTNM stage (p<0.05). Down-regulation of ZNF217 in CRC cells could significantly suppress cell migration andinvasion. Conclusions: ZNF217 is overexpressed in colorectal carcinoma tissues and is associated with tumormalignant clinicopathological features. ZNF217 may promote CRC progression by inducing cell migration andinvasion.     

ZNF668 functions as a tumor suppressor by regulating p53 stability and function in breast cancer

Genome-wide sequencing studies in breast cancer have recently identified frequent mutations in the zinc finger protein 668 (ZNF668), the function of which is undefined. Here, we report that ZNF668 is a nucleolar protein that physically interacts with and regulates p53 and its negative regulator MDM2. Through MDM2 binding, ZNF668 regulated autoubiquitination of MDM2 and its ability to mediate p53 ubiquitination and degradation. ZNF668 deficiency also impaired DNA damage-induced stabilization of p53. RNA interference-mediated knockdown of ZNF668 was sufficient to transform normal mammary epithelial cells. ZNF668 effectively suppressed breast cancer cell proliferation in vitro and tumorigenicity in vivo. Taken together, our studies identify ZNF668 as a novel breast tumor suppressor gene that functions in regulating p53 stability.     

Down-regulation of G9a triggers DNA damage response and inhibits colorectal cancer cells proliferation

G9a, a histone methyltransferase, is aberrantly expressed in some human tumor types. By comparing 182 paired colorectal cancer and peritumoral tissues, we found that G9a was highly expressed in colorectal cancer (CRC). Overexpression of G9a promoted CRC cells proliferation and colony formation, whereas knockdown of G9a inhibited CRC cells proliferation. Depletion of G9a increased the rate of chromosome aberration, induced DNA double strand breaks and CRC cells senescence. G9a inhibition synergistically increased γH2AX expression induced by topoisomerase I inhibitors and ultimately led to CRC cell death. The findings that down-regulation of G9a triggers DNA damage response and inhibits colorectal cancer cells proliferation may define G9a as potential oncotarget in CRC.     

基于GEPIA数据库分析SLC52A3在结直肠癌组织中的表达及临床病理意义

目的:通过研究SLC52A3在结直肠癌(CRC)组织中的表达及其与临床病理学参数的相关性,阐明其在CRC预后中的重要作用。方法:运用GEPIA大数据分析SLC52A3在正常结直肠组织和结直肠癌组织中的表达差异和其对胃癌预后的影响。收集2018年6月-2020年6月经手术切除的CRC患者石蜡标本84例。应用免疫组化方法检测84例CRC患者手术切除石蜡标本中SLC52A3表达情况和细胞定位。分析SLC52A3的表达与CRC临床病理指标的相关性。结果:数据库分析结果表明,与正常的结直肠组织相比,SLC52A3在结直肠癌组织中的表达显著提高,免疫组化结果显示,SLC52A3蛋白阳性信号定位于细胞膜。SLC52A3蛋白在84例CRC组织中低表达26例,高表达58例;在对应的84例CRC癌旁组织中9例呈高表达,75例为低表达,SLC52A3蛋白在CRC组织中的表达显著高于癌旁组织(P<0.01)。SLC52A3表达水平与CRC的肿瘤部位、肿瘤病理分化程度、浸润深度、TNM分期都明显相关,差异具有统计学意义(P<0.01)。在生存预后方面：SLC52A3高表达组的结直肠癌患者的生存率较高...     

Long Noncoding RNA PlncRNA-1 Promotes Colorectal Cancer Cell Progression by Regulating the PI3K/Akt Signaling Pathway

Accumulating evidence has indicated that long noncoding RNA (lncRNA) PlncRNA-1 plays an important regulatory role in cancers. However, the expression and biological functions of PlncRNA-1 in colorectal cancer (CRC) are still unclear. In the present study, we determined the expression of PlncRNA-1 in CRC and explored the function of PlncRNA-1 on CRC cell progression. The results showed that PlncRNA-1 was significantly increased in CRC tissues and cell lines; high PlncRNA-1 expression was associated with depth of invasion, lymph node metastasis, and TNM stage of CRC patients. Kaplan–Meier curve analysis showed that patients with high PlncRNA-1 expression had a poor overall survival. PlncRNA-1 knockdown remarkably reduced cell proliferation, migration, and invasion and promoted cell apoptosis in vitro. In vivo xenograft experiments showed that PlncRNA-1 inhibition significantly suppressed tumor growth. Finally, we used an agonist (740Y-P) of the PI3K/Akt signaling pathway; function assays showed that PlncRNA-1 exerted its effects by targeting the PI3K/Akt signaling pathway in CRC. Taken together, our data suggested that PlncRNA-1 might act as an oncogene in CRC progression and serve as a potential biomarker and therapeutic target for the treatment of CRC.     

MiR-4500 is epigenetically downregulated in colorectal cancer and functions as a novel tumor suppressor by regulating HMGA2

This study aimed to understand the exact function and potential mechanism of miR-4500 in colorectal cancer (CRC). In this study, the expression of miR-4500 was decreased in both CRC cells and tissues, and downregulated miR-4500 indicated advanced tumor stage and poor survival. By bisulfite sequencing analysis, we found that the CpG island in the promoter region of miR-4500 was hypermethylated in CRC cells and tissues compared with normal control cells and non-tumor tissues, respectively. Functionally, gain- and loss-of-function analyses indicated the tumor suppressor role of miR-4500: it suppressed cell proliferation, cell cycle progression, migration, and invasion. Predictive algorithms and experimental analyses identified HMGA2 as a direct target of miR-4500. Reintroducing HMGA2 impaired the inhibitory effects of miR-4500 on cell growth and motility. Clinically, higher HMGA2 protein expression in CRC tissues was associated with advanced tumor stage and poor survival. An inverse correlation was found between miR-4500 levels and HMGA2 protein expression. Taken together, this study provides the first evidence that miR-4500 functions as a novel tumor suppressor in the miR-4500/HMGA2 axis in colorectal carcinogenesis, and restoring miR-4500 expression might represent a promising therapeutic strategy for CRC.     

The lncRNA FEZF1-AS1 Promotes the Progression of Colorectal Cancer Through Regulating OTX1 and Targeting miR-30a-5p

Long noncoding RNAs (lncRNAs) participate in and regulate the biological process of colorectal cancer (CRC) progression. Our previous research identified differentially expressed lncRNAs in 10 CRC tissues and 10 matched nontumor tissues by next-generation sequencing (NGS). In this study, we identified an lncRNA, FEZF1 antisense RNA 1 (FEZF1-AS1), and further explored its function and mechanism in CRC. We verified that FEZF1-AS1 is highly expressed in CRC tissues and cell lines. Through functional experiments, we found that reduced levels of FEZF1-AS1 significantly suppressed CRC cell migration, invasion, and proliferation and inhibited tumor growth in vivo. Mechanistically, we discovered that reduced levels of the lncRNA FEZF1- AS1 inhibited the activation of epithelial–mesenchymal transition (EMT); the overexpression of orthodenticle homeobox 1 (OTX1) partially rescued the FEZF1-AS1-induced inhibition of protein expression. It indicated that FEZF1-AS1 may play a role in the occurrence and development of CRC by regulating the FEZF1-AS1/ OTX1/EMT pathway. Furthermore, it was reported that FEZF1-AS1 is located in both the nucleus and cytoplasm of HCT116 cells. Dual-luciferase reporter assays verified that FEZF1-AS1 directly binds miR-30a-5p and negatively regulated each other. Further, we showed that 5 -nucleotidase ecto (NT5E) is a direct target of miR-30a-5p, and the inhibition of miR-30a-5p expression partially rescued the inhibitory effect of FEZF1-AS1 on NT5E. Our results indicated that the mechanism by which FEZF1-AS1 positively regulates the expression of NT5E is through sponging miR-30a-5p. Our study demonstrated that lncRNA FEZF1-AS1 is involved in the development of CRC and may serve as a diagnostic and therapeutic target for CRC patients.     

RFC5, regulated by circ_0038985/miR-3614-5p,functions as an oncogene in the progression of colorectal cancer

Replication factor C 5 (RFC5) is involved in a variety of biological functions of cancer. However, the expression pattern of RFC5 and the underlying mechanisms in colorectal cancer (CRC) remain elusive. Here, we show that RFC5 is significantly upregulated in CRC tissues and cells. Patients with CRC and increased RFC5 levels have an unfavorable prognosis. RFC5 can promote the proliferation, migration, and invasion of CRC cells and inhibit the apoptosis of CRC cells. Additionally, upstream of RFC5, we constructed the competing endogenous RNA network and confirmed that RFC5 in this network was inhibited by miR-3614-5p by directly targeting its 3′-untranslated regions. We verified that circ_0038985, which is positively correlated with RFC5, directly targeted miR-3614-5p. Overexpression of circ_0038985 promoted CRC cell migration and invasion, and these effects were partially reversed by the reintroduction of miR-3614-5p. Moreover, we found that RFC5 may promote the vascular endothelial growth factor A (VEGFa)/vascular endothelial growth factor receptor 2 (VEGFR2)/extracellular signal-regulated protein kinase (ERK) pathway. The knockdown of RFC5 reduced CRC tumorigenesis in vivo. Collectively, these data demonstrate that the circ_0038985/miR-3614-5p/RFC5 axis plays a critical role in the progression of CRC, and RFC5 may promote CRC progression by affecting the VEGFa/VEGFR2/ERK pathway.     

结直肠癌组织中DDX5表达水平及其与患者预后的相关性

目的:探讨RNA解螺旋酶DDX5(p68)在结直肠癌（colorectal cancer,CRC）组织中的表达水平及其与结直肠癌患者预后的相关性。方法:选取2015年03月至2016年11月陆军军医大学第二附属医院收治的接受外科手术初治的213例结直肠癌患者,收集其临床资料、肿瘤组织石蜡标本;采用免疫组化方法检测肿瘤组织中DDX5蛋白表达情况;随访3年,分析DDX5蛋白表达水平与结直肠癌患者预后的关系。结果:截止2019年11月30日,共有202例患者完成随访;死亡23例,复发44例,共计67例,预后不良率为33.17%;预后不良组在肿瘤分化程度上低于预后良好组,淋巴结转移情况、肿瘤浸润型比例、临床分期上高于预后良好组,差异具有统计学意义（P＜0.05）;预后不良组肿瘤组织中DDX5蛋白表达水平高于预后良好组,差异具有统计学意义（P＜0.05）;以DDX5表达水平中位数为截点,DDX5高表达组3年无进展生存率为58.88%,低于DDX5低表达组的78.30%,DDX5高表达组疾病进展风险显著高于DDX5低表达组（P=0.002）;多因素Logistic分析显示,肿瘤低分化（OR=14.097）、淋巴结N1-2转移（OR=118.602）、高临床分期（OR=1 525.596）、浸润型生长（OR=2.533）及DDX5高表达（OR=8.958）是影响结直肠癌患者预后不良的独立危险因素（P＜0.05）。结论:结直肠癌组织中DDX5蛋白高表达可导致患者预后不良,可能是评估结直肠癌预后的一项生物标志物。