Nucleolar spindle-associated protein 1 promotes tumorigenesis and predicts poor prognosis in human esophageal squamous cell carcinoma

The microtubule binding protein, nucleolar spindle-associated protein 1 (NUSAP1), has a crucial function in mitosis and its expression is closely associated with carcinogenesis. Herein, we aimed to determine the function of NUSAP1 in the development of human esophageal squamous cell carcinoma (ESCC), and the association of NUSAP1 expression with ESCC. Immunohistochemical staining of ESCC tissue sections indicated that NUSAP1 was expressed to a higher degree in tumor tissues than in adjacent nontumor tissues. NUSAP1 levels were relevant closely to histological differentiation (P = 0.049). Overall survival was longer in patients with lower NUSAP1 levels ( P < 0.001). NUSAP1 expression ( P = 0.002), histological differentiation ( P < 0.001), tumor depth ( P = 0.045), lymph node metastases ( P < 0.001), and tumor-node-metastasis staging ( P = 0.008) were greatly associated with overall survival using univariate analysis. Multivariate analysis suggested that histological differentiation ( P = 0.014) and NUSAP1 expression ( P = 0.026) could be independent prognostic markers for ESCC. Additionally, the biological behavior of ESCC cells was investigated in vitro and in vivo. Suppression of NUSAP1 inhibited cellular proliferation and invasion, and induced cell cycle arrest and apoptosis in vitro. More importantly, knockdown of NUSAP1 led to inhibition of tumor formation in nude mice. These findings indicated that NUSAP1 is a potential prognostic biomarker in ESCC, and is an ESCC oncogene. Thus, NUSAP1 could represent a therapeutic target for ESCC.     

The G2/M regulator 14-3-3sigma prevents apoptosis through sequestration of Bax

In response to DNA damage and genotoxic stress, the p53 tumor suppressor triggers either cell cycle arrest or apoptosis. The G(2) arrest after damage is, in part, mediated by the p53 target, 14-3-3final sigma (final sigma). Colorectal tumor cells lacking final sigma are exquisitely sensitive to DNA damage. Here we analyzed the mechanism of this sensitivity in final sigma(-/-) as compared with final sigma(+/+) human colorectal tumor cells. Exposure to adriamycin resulted in rapid apoptosis only in final sigma(-/-) cells. This was further characterized by caspase-3 activation, p21(CIP1) cleavage, and CDK2 activation. Moreover, Bax was rapidly translocated out of the cytoplasm, and cytochrome c was released in final sigma(-/-) cells. Transient adenovirus-mediated reconstitution of final sigma in the final sigma(-/-) cells led to effective rescue of this phenotype and protected cells against apoptosis. The association of final sigma, Bax, and CDK1 in protein complexes may be the basis for this antiapoptotic mechanism. In conclusion, final sigma not only enforces the p53-dependent G(2) arrest but also delays the apoptotic signal transduction.     

Gain-of-function hot spot mutant p53R248Q regulation of integrin/FAK/ERK signaling in esophageal squamous cell carcinoma

PurposeTP53, encoding the protein p53, is among the most frequently mutated genes in all cancers. A high frequency of 60 – 90% mutations is seen in esophageal squamous cell carcinoma (ESCC) patients. Certain p53 mutants show gain-of-function (GoF) oncogenic features unrelated to its wild type functions.MethodsThis study functionally characterized a panel of p53 mutants in individual ESCC cell lines and assayed for GoF oncogenic properties.ResultsThe ESCC cell line with endogenous p53^R248Q expression showed suppressed tumor growth in an immunocompromised mouse model and suppressed colony growth in in vitro three-dimensional culture, when depleted of the endogenous p53 protein expression. This suppression is accompanied by suppressed cell cycle progression, along with reduced integrin expression and decreased focal adhesion kinase and extracellular-regulated protein kinase signaling and can be compensated by expression of a constitutively active mitogen-activated protein. P53^R248Q enhances cell proliferation upon glutamine deprivation, as compared to other non-GoF mutants.ConclusionsIn summary, study of the functional contributions of endogenous p53 mutants identified a novel GoF mechanism through which a specific p53 mutant exerts oncogenic features and contributes to ESCC tumorigenesis.     

LINC00473/miR-374a-5p regulates esophageal squamous cell carcinoma via targeting SPIN1 to weaken the effect of radiotherapy

Esophageal squamous cell carcinoma (ESCC) is the most prevalent type in esophageal cancers. Despite accumulating achievements in treatments of ESCC, patients still suffer from recurrence because of the treatment failures, one of the reasons for which is radioresistance. Therefore, it is a necessity to explore the molecular mechanism underlying ESCC radioresistance. Long intergenic noncoding RNA 473 (LINC00473) has been reported to be aberrantly expressed in several human malignancies. However, its biological function in radiosensitivity of ESCC remains to be fully understood. This study explored the role of LINC00473 in radiosensitivity of ESCC cells and whether LINC00473 acted as a competing endogenous RNA to realize its modulation on radioresistance. We found that LINC00473 was markedly upregulated in ESCC tissues and cell lines, and its expression was remarkably related to cellular response to irradiation. In addition, knockdown of LINC00473 could sensitize ESCC cells to radiation in vitro. As for the underlying mechanism, we uncovered that there was a mutual inhibition between LINC00473 and miR-374a-5p. Spindlin1 (SPIN1) was verified as a downstream target of miR-374a-5p, and LINC00473 upregulated SPIN1 expression through negatively modulating miR-374a-5p expression. Furthermore, we revealed that SPIN1 could aggravate the radioresistance of ESCC cells. Finally, overexpression of SPIN1 reversed the LINC00473 silencing-enhanced radiosensitivity in ESCC cells. To sum up, we demonstrated that LINC00473 facilitated radioresistance by regulating the miR-374a-5p/SPIN1 axis in ESCC.     

PAI-1过表达促进食管鳞癌细胞的侵袭和迁移

食管癌是常见的恶性肿瘤之一。由SERPINE1基因编码的纤溶酶原激活物抑制因子1(plasminogen activator inhibitor-1,PAI-1)已被报道在多种类型癌症患者的肿瘤组织中存在高表达并参与癌症进展。为探讨PAI-1蛋白在食管鳞癌中的作用及其分子机制,本研究首先利用Westernblot实验和酶联免疫吸附实验(enzyme linked immunosorbent assay, ELISA)检测各食管鳞癌细胞系中PAI-1的表达和分泌水平,结果显示,PAI-1高表达的食管鳞癌细胞系分泌至细胞外的PAI-1水平相对较高。进一步选取PAI-1表达及分泌水平均较高的KYSE150和KYSE450细胞系作为研究模型,通过si RNA(小干扰RNA)瞬时转染和Transwell实验证实敲降SERPINE1可显著抑制食管鳞癌KYSE150和KYSE450细胞的侵袭和迁移。同时,构建了慢病毒介导的SERPINE1稳定敲降细胞株KYSE150和KYSE450,将SERPINE1稳定敲降的细胞培养基中外源加入PAI-1蛋白进行Transwell回复实验,结果表明PAI-1过表达可增强食管鳞癌细胞的侵袭和迁移能力。体内实验结果显示,降低PAI-1表达可显著抑制食管鳞癌细胞的成瘤和肺转移能力。分子水平检测表明PAI-1过表达可激活AKT和ERK信号通路,免疫共沉淀(co-immunoprecipitation,Co-IP)实验结果进一步显示PAI-1可能与膜受体LRP1(LDLreceptor related protein1)存在相互作用。上述研究结果表明,PAI-1可能通过与LRP1相互作用进而促进食管鳞癌细胞的侵袭和迁移。     

LaminB1蛋白在食管鳞癌组织中表达的形态学观察

目的探讨laminB1蛋白在食管鳞癌患者的癌组织及上切缘正常粘膜上皮中表达的形态变化。方法制备组织切片原位核基质,应用免疫组化的方法检测核基质制备前后正常粘膜上皮及癌组织中laminB1的表达;同时提取组织核基质蛋白,应用Westen blot检测核基质蛋白中laminB1的表达。结果正常食管粘膜上皮及食管鳞癌组织核基质制备前后laiminB1表达的阳性率分别为:正常粘膜上皮93.3%、正常粘膜上皮核基质86.7%、癌组织96.7%、癌核基质86.7%。正常粘膜上皮laminB1表达阳性细胞从基底层至颗粒层逐渐减少,制备核基质后正常粘膜上皮核基质laminB1表达阳性细胞数目减少、强度明显减弱,阳性细胞集中于基底层,多数细胞整个胞核着色。癌组织laminB1表达阳性细胞散在分布,无规律;癌核基质laminB1表达阳性强度减弱,阳性颗粒在核周较集中。癌核基质laminB1表达的阳性强度比正常粘膜上皮核基质高,差异有显著性(x2=5.042,P<0.05)。Western blot检测显示正常粘膜核基质的laminB1条带比癌核基质弱。结论laminB1蛋白在食管正常粘膜上皮及食管鳞癌组织中广泛存在。制备核基质后,laminB1蛋白在癌核基质的表达比正常粘膜上皮核基质强;且癌核基质中laminB1的分布与正常粘膜上皮核基质存在差异。     

14-3-3sigma is down-regulated in human prostate cancer

The 14-3-3sigma is a negative regulator of the cell cycle, which is induced by p53 in response to DNA damage. It has been characterized as an epithelium-specific marker and down-regulation of the protein has been shown in breast cancers, suggesting its tumor-suppressive activity in epithelial cells. Here we demonstrate that 14-3-3sigma protein is down-regulated in human prostate cancer cell lines, LNCaP, PC3, and DU145 compared with normal prostate epithelial cells. Immunohistochemical analysis of primary prostate cells shows that the expression of 14-3-3sigma protein is epithelial cell-specific. Among prostate pathological specimens, > 95% of benign hyperplasia samples show significant and diffuse immunostaining of 14-3-3sigma in the cytoplasm whereas < 20% of carcinoma samples show positive staining. In terms of mechanisms for the down-regulation of 14-3-3sigma in prostate cancer cells, hypermethylation of the gene promoter plays a causal role in LNCaP cells as 14-3-3sigma mRNA level was elevated by 5-aza-2'-deoxycytidine demethylating treatment. Intriguingly, the proteasome-mediated proteolysis is responsible for 14-3-3sigma reduction in DU145 and PC3 cells, as 14-3-3sigma protein expression was increased by treatment with a proteasome inhibitor MG132. Furthermore, tumor necrosis factor-related apoptosis-inducing ligand enhances 14-3-3sigma gene and protein expression in DU145 and PC3 cells. These data suggest that 14-3-3sigma expression is down-regulated during the neoplastic transition of prostate epithelial cells.     

Epb41l3 suppresses esophageal squamous cell carcinoma invasion and inhibits MMP2 and MMP9 expression

EPB41L3 may play a role as a metastasis suppressor by supporting regular arrangements of actin stress fibres and alleviating the increase in cell motility associated with enhanced metastatic potential. Downregulation of epb41l3 has been observed in many cancers, but the role of this gene in esophageal squamous cell carcinoma (ESCC) remains unclear. Our study aimed to determine the effect of epb41l3 on ESCC cell migration and invasion. We investigated epb41l3 protein expression in tumour and non‐tumour tissues by immunohistochemical staining. Expression in the non‐neoplastic human esophageal cell line Het‐1a and four ESCC cell lines – Kyse150, Kyse510, Kyse450 and Caes17 – was assessed by quantitative Polymerase Chain Reaction (qPCR) and Western blotting. Furthermore, an EPB41L3 overexpression plasmid and EPB41L3‐specific small interfering RNA were used to upregulate EPB41L3 expression in Kyse150 cells and to downregulate EPB41L3 expression in Kyse450 cells, respectively. Cell migration and invasion were evaluated by wound healing and transwell assays, respectively. The expression levels of p‐AKT, matrix metalloproteinase (MMP)2 and MMP9 were evaluated. Expression of epb41l3 was significantly lower in tumour tissues than in non‐tumour tissues and in ESCC cell lines compared with the Het‐1a cell line. Kyse450 and Caes17 cells exhibited higher expression of epb41l3 than Kyse150 and Kyse510 cells. Overexpressing epb41l3 decreased Kyse150 cell migration and invasion, whereas EPB41L3‐specific small interfering RNA silencing increased these functions in Kyse450 cells. Furthermore, overexpressing epb41l3 led to downregulation of MMP2 and MMP9 in Kyse150 and Kyse510 cells. Our findings reveal that EPB41L3 suppresses tumour cell invasion and inhibits MMP2 and MMP9 expression in ESCC cells. Copyright © 2016 John Wiley & Sons, Ltd.     

LncRNA MIR31HG通过诱导细胞周期阻滞抑制食管鳞癌细胞增殖活性

本研究探讨lnc RNA MIR31HG对食管鳞癌细胞增殖活性的影响.利用定量PCR检测MIR31HG在食管鳞癌标本及其癌旁组织、人食管上皮细胞系Het-1A和食管鳞癌细胞系Eca-109、EC-1、KYSE30中的表达;采用过表达质粒pc DNA3.1-MIR31HG在食管鳞癌细胞系中过表达MIR31HG;MTT法和SRB法检测细胞增殖率;细胞周期分析试剂盒检测细胞周期进程;Caspase3活性检测试剂盒分析Caspase3活性;PCR和Western blot法检测p53、Caspase3及Bcl-2的m RNA和蛋白质表达水平.结果显示,食管癌组织中MIR31HG表达水平显著低于癌旁组织(P0.05);与Het-1A细胞相比,Eca-109、EC-1、KYSE30细胞中MIR31HG的表达均显著下调(P0.05),提示MIR31HG可能介导食管癌的发生发展.转染pc DNA3.1-MIR31HG可显著上调食管癌细胞中MIR31HG的m RNA表达(P0.01),且MIR31HG过表达可显著抑制食管癌细胞增殖活性(P0.05),减少S期细胞数(P0.05),增加G1期细胞数(P0.05),提示MIR31HG可能通过阻碍细胞周期G1期~S期进程抑制食管癌细胞增殖活性.此外,MIR31HG过表达显著增加Caspase3活性,增加Caspase3和p53的m RNA和蛋白质表达水平,同时抑制Bcl-2 m RNA和蛋白质表达水平.这表明,MIR31HG可通过抑制食管癌细胞的增殖活性阻碍食管癌的发生发展,这可能为食管癌的诊断和治疗提供新策略.     

ZD1839 (Gefitinib, 'Iressa'), an epidermal growth factor receptor-tyrosine kinase inhibitor, enhances the anti-cancer effects of TRAIL in human esophageal squamous cell carcinoma

The EGF (epidermal growth factor) receptor-tyrosine kinase inhibitor ZD1839 (Gefitinib, 'Iressa') blocks the cell signaling pathways involved in cell proliferation, survival, and angiogenesis in various cancer cells. TNF-related death apoptosis inducing ligand (TRAIL) acts as an anticancer agent. We investigated the antitumor effects of ZD1839 alone or in combination with TRAIL against human esophageal squamous cell cancer (ESCC) lines. Although all ESCC cells expressed EGF receptor at a protein level, the effect of ZD1839 on cell growth did not correlate with the level of EGFR expression and phosphorylation of EGF receptor protein in ESCC lines. ZD1839 caused a dose-dependent growth arrest at G0-G1 phase associated with increased p27 expression. As TE8 cells are resistant to TRAIL, we tested whether ZD1839 combined with TRAIL induced apoptosis of TE8 cells via the inhibition of EGF receptor signaling by ZD1839. ZD1839 inhibited the phosphorylation of Akt, and enhanced TRAIL-induced apoptosis via activation of caspase-3 and caspase-9, and inactivation of Bcl-xL. Our results indicated that ZD1839 has anti-cancer properties against human esophageal cancer cells. ZD1839 also augmented the anti-cancer activity of TRAIL, even in TRAIL-resistant tumors. These results suggest that treatment with ZD1839 and TRAIL may have potential in the treatment of ESCC patients.     

Chloride intracellular channel 1 promotes esophageal squamous cell carcinoma proliferation via mTOR signalling

ObjectivesTo investigate the clinical significance of Chloride Intracellular Channel 1 (CLIC1) expression in esophageal squamous cell carcinoma (ESCC) and its functional contribution and molecular mechanisms to the progression of ESCC.MethodsCLIC1 expression was analyzed by immunohistochemistry (IHC) in a cohort of 86 ESCC tissue specimens and paired normal adjacent esophageal tissues. Associations between clinicopathological features of ESCC and CLIC1 expression were determined. In vitro analyses examined CLIC1 expression in the ESCC cell lines KYSE150 and TE1 using RT-PCR and Western blotting. The downstream pathways of CLIC1 were detected by lentiviral shRNA knockdown and subsequent proteomic analyses. CLIC1 siRNA knockdown was performed in ESCC cell lines KYSE150 and TE1 and the functional effects of CLIC1 on the growth and proliferation of ESCC cells were evaluated combined with cell viability and colony formation assays; the mTOR signaling pathway-related proteins were detected by Western blotting based on the previous proteomic data.ResultsCLIC1 expression was significantly increased in ex vivo ESCC tissues compared with corresponding normal tissues, and the up-regulation was associated with clinical tumor node metastasis (TNM) classifications. Knockdown of CLIC1 inhibited in vitro cell proliferation of ESCC cell lines KYSE150 and TE1. CLIC1 knockdown down-regulated the protein expression of p-mTOR and the downstream targets Rictor and p-4EBP1 in both KYSE150 and TE1 cell lines. And the CLIC1 knockdown induced inhibition of cell proliferation on ESCC cells could be rescued by mTOR overexpression.ConclusionsCLIC1 expression increases during esophageal carcinogenesis and it may functionally contribute to the progression of ESCC through growth promotion effects by promoting the mTOR and downstream signaling pathway. CLIC1 therefore constitutes a candidate molecular biomarker of ESCC.     

Activation of calcium-sensing receptor increases TRPC3 expression in rat cardiomyocytes

Tumor protein p53-induced nuclear protein 1 (TP53INP1) is a well known stress-induced protein that plays a role in both cell cycle arrest and p53-mediated apoptosis. Loss of TP53INP1 expression has been reported in human melanoma, breast carcinoma, and gastric cancer. However, TP53INP1 expression and its regulatory mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. Our findings are in agreement with previous reports in that the expression of TP53INP1 was downregulated in 28% (10/36 cases) of ESCC lesions, and this was accompanied by significant promoter methylation. Overexpression of TP53INP1 induced G1 cell cycle arrest and increased apoptosis in ESCC cell lines (EC-1, EC-109, EC-9706). Furthermore, our study showed that the oncoprotein c-Myc bound to the core promoter of TP53INP1 and recruited DNA methyltransferase 3A to methylate the local promoter region, leading to the inhibition of TP53INP1 expression. Our findings revealed that TP53INP1 is a tumor suppressor in ESCC and that c-Myc-mediated DNA methylation-associated silencing of TP53INP1 contributed to the pathogenesis of human ESCC.     

Molecular cloning and analysis of an eIF-4A-related rat liver nuclear protein.

In this paper, we report the cloning and analysis of a cDNA encoding a protein of M(r) congruent to 47,000 (p47), which is localized to the nucleus of rat hepatocytes. The cDNA showed 37% overall sequence identity with a mouse translation initiation factor, eIF-4A, which belongs to a family of putative ATP-dependent RNA helicases. We raised polyclonal antibodies against the fusion protein and by indirect immunofluorescence on primary cultures of hepatocytes have demonstrated that p47 is located in the nucleus. Although only approximately 27% of hepatocytes showed this nuclear staining, most of the nuclei in proliferating transformed cell lines such as 3T3, PtK-1, and Hela were fluorescently labeled. Studies on serum-starved cells in culture indicated that p47 was expressed in a cell cycle-dependent manner. Northern analyses demonstrated that the levels of p47 mRNA were high in fetal liver and dropped significantly after birth to low levels in adult liver. Our data suggest that p47 is developmentally regulated in rat liver at the mRNA level.