Expression of klotho and β‐catenin in esophageal squamous cell carcinoma,and their clinicopathological and prognostic significance

Esophageal carcinoma is one of the most common types of cancers in the world; the molecular mechanism underlying its tumorigenesis is still not well understood. This study was aimed at investigating the expression of klotho and β‐catenin in patients with esophageal squamous cell carcinoma (ESCC) and analyzing their association with clinicopathological variables and their effects on prognosis. The expression patterns of klotho and β‐catenin were determined by tissue microarray and immunohistochemical technique in ESCC and normal tissues, and their correlations with clinicopathological characteristics were investigated using univariate and multivariate analysis. The serum klotho levels in 40 ESCC patients and controls were measured by sandwich enzyme‐linked immunosorbent assay system (ELISA). The expression level of klotho was significantly lower in ESCC than in the adjacent noncancerous tissues (30 vs. 50%, P < 0.000), and the protein level was negative correlated with clinical staging, histological grade, lymph node metastasis, and invasion depth (P < 0.05). Whereas, the expression of β‐catenin was much higher in ESCC than their corresponding normal mucosa tissues (78.3 vs. 11.5%, P < 0.000), and the level of protein correlated only with histological grade and invasion depth (P < 0.05). Correlation analysis showed the expression level of klotho inversely correlated with that of β‐catenin (r = ?0.214, P < 0.01). Patients with klotho‐positive tumors had longer survival than those with klotho‐negative tumors (P < 0.01). Cox proportional hazards model analysis demonstrated that positive expression of klotho was an important factor indicating good prognosis (hazard ratio, 0.371; 95% confidence interval, 0.201–0.685; P < 0.01). ELISA showed that the level of serum klotho was markedly higher (461.50 ± 43.30 pg/mL) than control group (239.37 ± 20.65 pg/mL) (P < 0.001). Receiver operating characteristic analysis gave a cut‐off value of 327.031 of serum klotho with a sensitivity of 81.3% and specificity of 81.2% (P < 0.000). Our present study demonstrated for the first time that klotho might be a novel biomarker candidate for predicting progression and prognosis in patients with ESCC.     

HIF-1α induces VE-cadherin expression and modulates vasculogenic mimicry in esophageal carcinoma cells

AIM: To investigate whether hypoxia inducible factor (HIF)-1α modulates vasculogenic mimicry (VM) by upregulating VE-cadherin expression in esophageal squamous cell carcinoma (ESCC).METHODS: Esophageal squamous cancer cell lines Eca109 and TE13 were transfected with plasmids harboring small interfering RNAs targeting HIF-1α or VE-cadherin. The proliferation and invasion of esophageal carcinoma cells were detected by MTT and Transwell migration assays. The formation of tubular networks of cells was analyzed by 3D culture in vitro. BALB/c nude mice were used to observe xenograft tumor formation. The relationship between the expression of HIF-1α and VE-cadherin, ephrinA2 (EphA2) and laminin5γ2 (LN5γ2) was measured by Western blot and real-time polymerase chain reaction.RESULTS: Knockdown of HIF-1α inhibited cell proliferation (32.3% ± 6.1% for Eca109 cells and 38.6% ± 6.8% for TE13 cells, P < 0.05). Both Eca109 and TE13 cells formed typical tubular networks. The number of tubular networks markedly decreased when HIF-1α or VE-cadherin was knocked down. Expression of VE-cadherin, EphA2 and LN5γ2 was dramatically inhibited, but the expression of matrix metalloproteinase 2 had no obvious change in HIF-1α-silenced cells. Knockdown of VE-cadherin significantly decreased expression of both EphA2 and LN5γ2 (P < 0.05), while HIF-1α expression was unchanged. The time for xenograft tumor formation was 6 ± 1.2 d for Eca109 cells and Eca109 cells transfected with HIF-1α Neo control short hairpin RNA (shRNA) vector, and 8.4 ± 2.1 d for Eca109 cells transfected with an shRNA against HIF-1α. Knockdown of HIF-1α inhibited vasculogenic mimicry (VM) and tumorigenicity in vivo.CONCLUSION: HIF-1α may modulate VM in ESCC by regulating VE-cadherin expression, which affects VM formation through EphA2 and LN5γ2.     

Effect of mutant β‐catenin on liver growth homeostasis and hepatocarcinogenesis in transgenic mice

Background: Mutations in the Wnt signalling pathway molecule β‐catenin are associated with liver cancer. Aims: Our aim was to confirm the effects of stabilized β‐catenin on liver growth, identify whether those effects were reversible and cell autonomous or non‐cell autonomous and to model β‐catenin‐induced liver cancer in mice. Methods: Using a liver‐specific inducible promoter, we generated transgenic mice in which the expression of mutant β‐catenin can be induced or repressed within hepatocytes in mice of different ages. Results: Similar to other models, the hepatic expression of mutant β‐catenin in our model beginning in utero or induced in quiescent adult liver resulted in a two‐fold liver enlargement and development of disease with a latency of 1–5 months, and mice displayed elevated blood ammonia and altered hepatic gene expression. Our model additionally allowed us to discover that molecular and phenotypic abnormalities were reversible following the inhibition of transgene expression. Hepatocyte transplant studies indicated that mutant β‐catenin could not increase the growth of transgene‐expressing foci in either growth‐permissive or ‐restrictive hepatic environments, but still directly altered hepatocyte gene expression. Mice with continuous but focal transgene expression developed hepatic neoplasms after the age of 1 year. Conclusions: Our findings indicate that hepatocyte gene expression is directly affected by mutant β‐catenin in a cell autonomous manner. However, hepatomegaly associated with diffuse hepatocyte‐specific expression of mutant β‐catenin is secondary to liver functional alteration or non‐cell autonomous. Both phenotypes are reversible. Nevertheless, some foci of transgene‐expressing cells progressed to carcinoma, confirming the association of mutant β‐catenin with liver cancer.     

食管鳞癌中微小核糖核酸let-7的表达及病理生物学意义

目的 探讨微小RNA(miRNA)1et-7对食管鳞癌细胞增殖的影响及食管鳞癌组织中let-7表达水平与临床病理特征间的关系.方法 利用RNA干扰(RNAi)和细胞转染技术将食管鳞癌细胞Eca109分别转染入let-7、let-7抑制剂及随机序列.以正常培养的Eca109细胞为阴性对照组.噻唑蓝(MTT)比色法检测各组Eca109细胞的增殖情况.实时荧光定量聚合酶链反应(qRTPCR)检测各组细胞、45例食管鳞癌组织及其癌旁组织中let-7的表达水平,并分析其与食管鳞癌临床病理特征间的关系.结果 转染后72 h,转染let-7组吸光度(A)值较阴性对照组明显降低(P=0.005),转染let-7抑制剂组A值较阴性对照组明显升高(P=0.029).与阴性对照组let-7表达量比较,转染let-7组表达增加33%(1.33比1.00,P=0.039),转染let-7抑制剂组表达降低50%(0.50比1.00,P=0.014).食管鳞癌组织和癌旁组织中let-7相对表达量的比值为0.66±0.47,差异有统计学意义(P=0.001).汉族患者食管鳞癌组织中let-7相对表达量(0.48±0.43)低于哈萨克族(0.88±0.51,P=0.019).低分化食管鳞癌组织中let-7相对表达量(0.42±0.30)低于高分化食管鳞癌组织(0.84±0.38,P=0.015).有淋巴结转移者食管鳞癌组织中let-7相对表达量(0.50±0.35)低于无淋巴结转移者(0.80±0.52,P=0.032).结论 let-7对食管鳞癌的发生、发展起抑制作用,其表达水平与组织分化程度、淋巴结转移及民族相关.

Abstract：

Objective To estimate the effect of microRNA (miRNA) let-7 expression on human esophageal squamous cell carcinoma(ESCC) and the relationship between let-7 level and clinicopathological parameters. Methods ESCC cell line (Eca109) was transfected with let-7 or its inhibitor by RNAi and cell transfection techniques. Normal cultured Eca109 cell was served as negative control. The proliferation of Eca109 cell was detected by MTT. The expression of let-7 in Eca109 cells and 45 paired ESCC tissues and corresponding para-cancerous tissues were measured using real-time quantitative polymerase chain reaction (qRT-PCR). The relationship between let-7 level and clinicopathological parameters in patients with ESCC was analyzed. Results The A value of let-7 in Eca109 cells transfected with let-7 was lower than negative control (P=0.005), while it was higher in Eca109 cells transfected inhibitor than that in negative control 72 hours after transfection. In comparison with negative control, the expression of let-7 in Eca109 cells transfected with let-7 was increased 33% (1.33 vs 1.00,P=0. 039) and it was decreased 50% in Eca109 cells transfected with inhibitor (0.50 vs 1.00,P=0. 014). The ratio of let-7 expression in ESCC tissue and para-cancerous tissue was 0.66 ± 0.47 with significant differece (P= 0.001). Moreover, The level of let-7 expression in Han patients with ESCC was lower than Kazakh patients with ESCC (0.48±0.43 vs 0. 88±0.51,P=0. 019). The level of let-7 expression in poorly differentiated ESCC tissue was lower than well differentiated ESCC tissue (0.42±0.30 vs 0.84±0.38,P=0. 015). The level of let-7 expression in patients with lymph node metastasis was lower than those without lymph node metastasis (0.50±0.35vs 0. 80±0.52,P=0. 032) . Conclusion It is demonstrated that let-7 can inhibit the carcinogenesis and development of ESCC. The level of let-7 expression is associated with cell differentiation,lymph node metastasis and nationalities.     

RNA干扰HIF-1α对食管鳞癌血管生成拟态的影响

背景:研究表明大量高度恶性肿瘤组织中存在血管生成拟态(VM),其分子机制已形成相关假说,但确切机制和关键信号通路尚未明确。目的:探讨缺氧诱导因子(HIF)-1α在食管鳞癌VM形成中的作用。方法:设计合成3种HIF-1α-siRNA质粒,测序后瞬时转染293T细胞,蛋白质印迹法鉴定质粒的干扰效果。将筛选出的pGCsi-HIF3质粒稳定转染食管鳞癌细胞株Eca109和TE13,以蛋白质印迹法检测干扰效果,三维培养法观察VM形成情况,蛋白质印迹法检测VE-cadherin、EphA2、LN5γ2和MMP2蛋白表达。结果:成功构建了3个靶位的质粒,其中pGCsiHIF3的干扰效果最好。pGCsi-HIF3稳定转染食管鳞癌细胞株Eca109和TE13后,与对照组相比,HIF-1α表达明显降低,细胞体外管道形成能力被明显抑制(P0.05)。常氧下转染组细胞中VE-cadherin、EphA2、LN5γ2均显著下调(P0.05),MMP2表达无明显差异,且缺氧条件下上述指标蛋白表达无明显增加。结论:Eca109和TE13细胞能形成管状结构,HIF-1α可能通过调节VE-cadherin、EphA2、LN5γ2等的表达而调节食管鳞癌VM的形成。     

Immunohistochemical study of nuclear factor‐κB expression in esophageal squamous cell carcinoma: prognostic significance and sensitivity to treatment with 5‐FU

Nuclear factor‐κB (NF‐κB) is expressed in many types of cancers. It has been suggested that the expression of NF‐κB is associated with poor prognosis and resistance to chemoradiation therapies. This study evaluated the relationship between the expression of NF‐κB and the prognosis and sensitivity of esophageal squamous cell carcinoma (ESCC) to chemotherapy. One hundred and nine ESCC specimens, from patients who had undergone radical esophagectomy, were divided into two groups depending on the expression of NF‐κB. Surgical data and prognosis were compared between the two groups. NF‐κB‐positive tumors were detected in 61.5% of the cases. In 69 patients with stage II and III disease, 41 patients who were NF‐κB‐positive showed poor survival. The sensitivity of esophageal squamous cell carcinoma cell lines to 5‐fluorouracil (5‐FU) was analyzed by their NF‐κB expression, and the effect of 5‐FU was evaluated on the proliferation and activity of two cell lines of cultured ESCCs expressing NF‐κB. ESCCs with activated NF‐κB had poor sensitivity to 5‐FU. These results suggest that the increased expression of NF‐κB is associated with poor prognosis in patients with ESCC. NF‐κB may be a target for ESCC therapy because of its selective expression in this type of cancer.     

Association of mu‐opioid receptor expression with lymph node metastasis in esophageal squamous cell carcinoma

The mu‐opioid receptor (MOR), a membrane‐bound G protein‐coupled receptor, is the main target for opioids in the nervous system. MOR1 has been found in several types of cancer cells and reported to be involved in tumor progression and metastasis. However, the expression and clinical significance of MOR1 in esophageal squamous cell carcinoma (ESCC) remain unclear. In our study, the expression of MOR1 was confirmed in ESCC cell lines (KYSE180, KYSE150, and EC109) by Western blot. MOR1 was also detected on tissue microarrays of ESCC samples in 239 cases using immunohistochemical staining. We found that MOR1 was mainly located in the cytoplasm and occasionally occurred in the membrane or nucleus of ESCC cells. Moreover, results indicated that MOR1 expression in the cytoplasm was associated with lymph node metastasis (R = 0.164, P = 0.008, Kendall's tau‐b‐test). No more associations were found between MOR1 expression status and other clinical parameters. However, no statistical significant differences were found between MOR1 expression in the cytoplasm, nucleus/membrane, and the overall survival of ESCC patients (P = 0.848; P = 0.167; P = 0.428, respectively, log‐rank test). Our results suggest that the cytoplasmic MOR1 may be a high‐risk factor for lymph node metastasis of ESCC patients. We also hypothesize that MOR1 agonists used in ESCC patients should be prudent, and opioid receptor antagonists may be novel therapeutic drugs for ESCC patients.     

MTNR1B loss promotes chordoma recurrence by abrogating melatonin‐mediated β‐catenin signaling repression

Chordoma is an extremely rare malignant bone tumor with a high rate of relapse. While cancer stem cells (CSCs) are closely associated with tumor recurrence, which depend on its capacity to self‐renew and induce chemo‐/radioresistance, whether and how CSCs participate in chordoma recurrence remains unclear. The current study found that tumor cells in recurrent chordoma displayed more dedifferentiated CSC‐like properties than those in corresponding primary tumor tissues. Meanwhile, MTNR1B deletion along with melatonin receptor 1B (MTNR1B) down‐regulation was observed in recurrent chordoma. Further investigation revealed that activation of Gαi2 by MTNR1B upon melatonin stimulation could inhibit SRC kinase activity via recruiting CSK and SRC, increasing SRC Y530 phosphorylation, and decreasing SRC Y419 phosphorylation. This subsequently suppressed β‐catenin signaling and stemness via decreasing β‐catenin p‐Y86/Y333/Y654. However, MTNR1B loss in chordoma mediated increased CSC properties, chemoresistance, and tumor progression by releasing melatonin's repression of β‐catenin signaling. Clinically, MTNR1B deletion was found to correlate with patients’ survival. Together, our study establishes a novel convergence between melatonin and β‐catenin signaling pathways and reveals the significance of this cross talk in chordoma recurrence. Besides, we propose that MTNR1B is a potential biomarker for prediction of chordoma prognosis and selection of treatment options, and chordoma patients might benefit from targeting MTNR1B/Gαi2/SRC/β‐catenin axis.     

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

AIM To explore the effect of mi R-382 on esophageal squamous cell carcinoma(ESCC) in vitro and its possible molecular mechanism.METHODS Eca109 cells derived from human ESCC and Het-1A cells derived from human normal esophageal epithelium were used. Lentivirus-mediated mi R-382 was overexpressed in Eca109 cells. The effect of mi R-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/m L PI and 100 mg/m L RNase A, and analyzed by BD FACSCalibur? 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 mi R-382 was down-regulated in Eca109 cells compared with Het-1A. Introduction of mi R-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 epithelialmesenchymal transition of Eca109 cells were suppressed by overexpressing mi R-382. Western blotting results showed that mi R-382 inhibited the phosphorylation of m TOR and 4E-BP1. CONCLUSION mi R-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.     

EphA2在缺氧条件下的表达及其对食管癌细胞体外三维培养的影响

目的:探讨在正常氧分压和缺氧条件下,食管癌细胞中上皮细胞激酶A2(EphA2)表达变化及其对体外三维培养的影响.方法:正常氧分压及缺氧条件下培养食管癌Ecal09及TE13细胞,RT-PCR及Western blot 分别监测细胞中EphA2表达的变化:EphA2 miRNA干扰质粒转染Ecal09和TE13细胞后,采...     

新疆哈萨克族食管鳞癌中微小RNA let-7的表达及病理生物学意义

目的探讨微小RNA（miRNA）let-7在食管鳞癌细胞及组织中的表达,及let-7与食管鳞癌临床病理的关系。方法在细胞水平,运用实时荧光定量聚合酶链反应（real-time quantitative PCR,qRT-PCR）检测let-7在正常食管鳞状上皮细胞Heepic及食管鳞癌细胞CaES-17、Eca109和KYSE-150中的表达差异;在组织水平,采用qRT-PCR技术检测let-7在15对哈萨克族食管鳞癌组织和癌旁正常组织中的表达,并分析其与食管鳞癌浸润、转移等临床病理的关系。结果 qRT-PCR结果显示,let-7在3个食管鳞癌细胞系中的表达明显低于在正常食管鳞状上皮细胞Heepic中的表达,let-7在食管鳞癌组织中的表达明显低于其在癌旁正常组织中的表达,其相对表达量比值为0.79±0.56,差异有统计学意义（P〈0.05）;let-7在不同性别、分化程度、大体分型、浸润深度及淋巴结转移之间的相对表达量比值均无统计学差异（P〉0.05）。结论 Let-7在正常食管鳞状上皮细胞和食管鳞癌细胞中均有表达,但在食管鳞癌细胞中呈低表达;let-7在食管鳞癌组织和正常食管鳞状上皮组织中均有表达,但在癌组织中呈显著低表达;哈萨克族食管鳞癌患者let-7低表达与其临床病理参数之间无显著相关性;let-7对哈萨克族食管鳞癌的发生起抑制作用,是食管鳞癌的潜在分子标记物。     

β‐catenin regulates parathyroid hormone/parathyroid hormone–related protein receptor signals and chondrocyte hypertrophy through binding to the intracellular C‐terminal region of the receptor

Objective

To investigate the underlying mechanisms of action and functional relevance of β‐catenin in chondrocytes, by examining the role of β‐catenin as a novel protein that interacts with the intracellular C‐terminal portion of the parathyroid hormone (PTH)/PTH‐related protein (PTHrP) receptor type 1 (PTHR‐1).

Methods

The β‐catenin–PTHR‐1 binding region was determined with deletion and mutagenesis analyses of the PTHR1 C‐terminus, using a mammalian two‐hybrid assay. Physical interactions between these 2 molecules were examined with an in situ proximity ligation assay and immunostaining. To assess the effects of gain‐ and loss‐of‐function of β‐catenin, transfection experiments were performed to induce overexpression of the constitutively active form of β‐catenin (ca‐β‐catenin) and to block β‐catenin activity with small interfering RNA, in cells cotransfected with either wild‐type PTHR1 or mutant forms (lacking binding to β‐catenin). Activation of the G protein α subunits G_αs and G_αq in the cells was determined by measurement of the intracellular cAMP accumulation and intracellular Ca²⁺ concentration, while activation of canonical Wnt pathways was assessed using a TOPflash reporter assay.

Results

In differentiated chondrocytes, β‐catenin physically interacted and colocalized with the cell membrane–specific region of PTHR‐1 (584–589). Binding of β‐catenin to PTHR‐1 caused suppression of the G_αs/cAMP pathway and enhancement of the G_αq/Ca²⁺ pathway, without affecting the canonical Wnt pathway. Inhibition of Col10a1 messenger RNA (mRNA) expression by PTH was restored by overexpression of ca‐β‐catenin, even after blockade of the canonical Wnt pathway, and Col10a1 mRNA expression was further decreased by knockout of β‐catenin (via the Cre recombinase) in chondrocytes from β‐catenin–floxed mice. Mutagenesis analyses to block the binding of β‐catenin to PTHR1 caused an inhibition of chondrocyte hypertrophy markers.

Conclusion

β‐catenin binds to the PTHR‐1 C‐tail and switches the downstream signaling pathway from G_αs/cAMP to G_αq/Ca²⁺, which is a possible mechanism by which chondrocyte hypertrophy may be regulated through the PTH/PTHrP signal independent of the canonical Wnt pathway.