miR-21和PDCD4在非小细胞肺癌中的表达及其临床意义

目的:探讨微小核糖核酸21（miR-21）和程序性细胞死亡因子4（programmed cell death 4,PDCD4）在非小细胞肺癌(NSCLC)组织中的表达及临床意义。方法:应用Real-time PCR法检测61例NSCLC组织及61例对应癌旁肺组织中miR-21、PDCD4的表达,分析二者表达的相关性及其与临床病理特征和预后的关系。结果:同癌旁正常组织相比,NSCLC组织中miR-21 mRNA表达明显上调（88.52%,P=0.000）,PDCD4 mRNA表达明显下调（83.61%,P=0.000）。两者表达呈负相关（r＝0．044,P＜0.05）。中晚期（Ⅲ-Ⅳ期）肺癌组织中miR-21 mRNA表达高于早期（Ⅰ-Ⅱ期）（P＜0.05）。PDCD4 mRNA 表达与NSCLC的分化程度、临床分期及淋巴转移相关（P＜0.05）。Kaplan-Meier 生存分析显示miR-21高表达患者较低表达患者总生存期明显缩短（P=0.007）,相反,PDCD4高表达的患者较低表达患者具有较长的总生存期(P=0.003)。     

Milk fat globule epidermal growth factor 8 serves a novel biomarker of opisthorchiasis-associated cholangiocarcinoma

Milk fat globule epidermal growth factor 8 (MFG-E8) is a pleiotropic secreted glycoprotein to play roles in mediating immune tolerance and homeostasis maintenance and enhancing angiogenesis. To evaluate its value as a biomarker in opisthorchiasis-associated cholangiocarcinoma (CCA), the present study investigated MFG-E8 expression kinetics during the tumorigenesis in Opisthorchis viverrini infection-induced CCA, and demonstrated its expression in the tumor tissues of CCA patients and its serum level among them. During the tumorigenesis of CCA, MFG-E8 expression was increased in a time-dependent manner with the pathological processes. Absolutely higher expression of MFG-E8 messenger RNA was detected in the tumor tissues from CCA patients, compared with those in adjacent tissues. Immunobiochemical analysis showed that more than 90 % CCA cases were positive and the positive reaction located in the membrane and cytoplasm of the tumor cells. Moreover, the average serum level in the CCA patients was significantly higher than that in healthy individuals and those with O. viverrini infection or other parasitosis. Correlation analysis of MFG-E8 expression with CCA clinicopathology revealed that a high expression of MFG-E8 protein was significantly bound with a poor differentiation, pathological advanced stage, and metastasis of CCA. The multivariation analysis indicated that MFG-E8 was an independent prognostic factor. In addition, short hairpin RNA-mediated MFG-E8 knockdown in CCA cell line obviously suppressed the cell proliferation. Our results strongly suggested that MFG-E8 is a promising biomarker for the diagnosis, prognosis, and therapy target of opisthorchiasis-associated CCA.     

RETRACTED ARTICLE: Downregulation of miR-185 and upregulation of miR-218 expression may be potential diagnostic and prognostic biomarkers of human chondrosarcoma

Increasing evidence has confirmed that dysregulation of microRNAs (miRNAs) can contribute to the progression and metastasis of human tumors. Chondrosarcoma is the most common primary malignant bone tumor in adults and has no effective systemic treatment, and patients with this disease have poor survival. Thus, it is important to find new diagnostic markers and improve treatment options. In the current study, we are interested to examine the role of miR-185 and miR-218 expression in patients with chondrosarcoma using real-time PCR. Moreover, the association of the two miRNAs with clinicopathological features and prognosis was evaluated. Survival and Cox proportional hazards analyses were performed to find the association of miR-185 expression and miR-218 levels with prognosis in the patients. Our results indicated that the miR-185 expression was significantly downexpressed in clinical chondrosarcoma bone tissues compared with adjacent normal tissues (P?=?0.001). MiR-218 expression level was increased in clinical chondrosarcoma bone tissue than those adjacent normal tissues (P?=?0.001). Decreased expression of miR-185 showed remarkable correlation with advanced tumor stage (P?=?0.019), tumor grade (P?<?0.001), and distant metastasis (P?=?0.001). Moreover, high expression of miR-218 was strongly correlated with advanced tumor stage (P?=?0.014), tumor grade (P?<?0.001), and distant metastasis (P?=?0.002). Kaplan–Meier survival analysis revealed that the low miR-185 expression group and the high miR-218 expression group had remarkably shorter overall survival (log-rank test P?=?0.007, P?=?0.004). The multivariate Cox proportional hazards model indicated that decreased expression of miR-185 and increased expression of miR-218 (P?=?0.017, P?=?0.012), advanced tumor stage (P?=?0.006, P?=?0.012), tumor grade (P?=?0.032, P?=?0.016), and distant metastasis (P?=?0.004, P?=?0.015) were independently related to overall survival in patients with chondrosarcoma. In conclusion, downregulation of miR-185 and upregulation of miR-218 can be associated with progression of chondrosarcoma and also both of them may act as tumor suppressor genes in chondrosarcoma.     

Prognostic significance of PDCD4 expression and association with microRNA-21 in each Dukes' stage of colorectal cancer patients

Down-regulation of the novel tumor suppressor gene programmed cell death 4 (PDCD4) was demonstrated in several types of cancer and regulation by micro-RNA is gaining attention. However, the clinical significance of the PDCD4 gene in colorectal cancer (CRC) patients still remains unclear. In particular, the significance of PDCD4 mRNA expression in each tumor stage has not been reported. In this study, we evaluated the prognostic value of PDCD4 expression in each Dukes' stage of CRC patients. Furthermore, relationships between the PDCD4 mRNA and microRNA-21 (miR-21) were evaluated. Tumor tissues and normal adjacent tumor tissues from 326 patients with CRC (Dukes' stage A, 44 cases; Dukes' B, 118 cases; Dukes' C, 100 cases; Dukes' D, 64 cases) were examined. The PDCD4 mRNA was investigated by the quantitative real-time RT-PCR method and miR-21 was examined by TaqMan microRNA assays. The overall survival rates (OS) and disease-free survival rates (DFS) of low PDCD4 patients were significantly worse than those of patients with high expression. In analysis of each tumor stage, OS and DFS of patients with low PDCD4 levels were significantly worse than those with high PDCD4 levels in Dukes' stage B and C. In Dukes' stage D, patients with low PDCD4 expression showed a significant worse OS compared to those of patients with high PDCD4 expression. In contrast, no significant differences were seen between these groups in patients with Dukes' stage A. PDCD4 expression in CRC tissues was an independent prognostic factor in Dukes' stage B, C and D. Significant inverse correlations were demonstrated between PDCD4 and miR-21. The reduced PDCD4 mRNA expression is associated with poor prognosis in CRC patients with Dukes' stage B, C and D. Furthermore, PDCD4 mRNA levels were negatively regulated by miR-21in each tumor stage of CRC.     

MicroRNA-21 suppression impedes medulloblastoma cell migration

Medulloblastoma (MB), the most common malignant brain tumour in children, is characterised by a high risk of leptomeningeal dissemination. But little is known about the molecular mechanisms that promote cancer cell migration in MB. Aberrant expression of miR-21 is recognised to be causatively linked to metastasis in a variety of human neoplasms including brain tumours; however its function in MB is still unknown. In this study we investigated the expression level and the role of miR-21 in MB cell migration. miR-21 was found to be up-regulated, compared to normal cerebellum, in 29/29 MB primary samples and 6/6 MB-derived cell lines. Inverse correlation was observed between miR-21 expression and the metastasis suppressor PDCD4, while miR-21 repression increased the release of PDCD4 protein, suggesting negative regulation of PDCD4 by miR-21 in MB cells. Anti-miR-21 decreased protein expression of the tumour cell invasion mediators MAP4K1 and JNK, which are also known to be negatively regulated by PDCD4, and down-regulated integrin protein that is essential for MB leptomeningeal dissemination. Moreover miR-21 knockdown in MB cells increased the expression of two eminent negative modulators of cancer cell migration, E-Cadherin and TIMP2 proteins that are known to be positively regulated by PDCD4. Finally and importantly, suppression of miR-21 decreased the motility of MB cells and reduced their migration across basement membranes in vitro. Together, these compelling data propose miR-21 pathway as a novel mechanism impacting MB cell dissemination and raises the possibility that curability of selected MB may be improved by pharmaceutical strategies directed towards microRNA-21.     

miR-21调控非小细胞肺癌细胞增殖和凋亡的机制研究

目的 研究非小细胞肺癌(NSCLC)中高表达的miR-21对细胞增殖和凋亡的影响及其调控机制.方法 采用荧光定量聚合酶链反应检测miR-21在人NSCLC组织、癌旁组织和A549细胞系中的表达.通过序列分析预测被miR-21调控的抑癌基因,通过荧光素酶活性检测和Western blot 检测验证miR-21对靶基因表达调控的影响.采用RNA干扰技术抑制miR-21和程序性细胞死亡因子4(PDCD4),以台盼蓝染色和流式细胞术检测A549细胞增殖和凋亡的变化.结果 NSCLC组织和A549细胞中miR-21的表达水平分别为癌旁组织的2.24倍和3.06倍.序列预测和基因表达调控研究表明,miR-21可以在NSCLC中反向调控PDCD4的表达(P＜0.01).荧光素酶活性检测结果显示,共同转入Wt 3'UTR和miR-21会显著抑制A549细胞中的荧光素酶表达(P＜O.001).Western blot检测结果显示,导入反义寡核苷酸抑制miR-21的功能后,PDCD4的表达水平明显上升.抑制miR-21的作用可以显著抑制A549细胞的增殖,并使细胞凋亡率由2.6％上升到10.9％,而抑制PDCD4的表达可以在很大程度上消除miR-21介导的细胞增殖障碍,抑制细胞凋亡.结论 在NSCLC中,抑制抑癌基因PDCD4的表达可能是miR-21介导肿瘤细胞增殖、抵抗凋亡的重要途径之一.     

Decreased expression of microRNA-206 correlates with poor clinical outcome in patients with malignant astrocytomas

MicroRNA-206 (miR-206) has been proved to function as a tumor suppressor in several types of human malignant cancers. More recently, it has been demonstrated that the ectopic expression of miR-206 significantly inhibited the proliferation and promoted apoptosis at the early stages in glioma cell U343. In order to investigate the clinical significance of miR-206 expression in human astrocytoma, quantitative real-time polymerase chain reaction (qRT-PCR) analysis was used to characterize the expression patterns of miR-206 in 108 astrocytoma and 20 normal brain tissues. As the results, the expression levels of miR-206 in astrocytoma tissues were significantly lower than those in normal brain tissues (P?<?0.001). Additionally, the decreased expression of miR-206 in astrocytoma was significantly associated with advanced pathological grade (P?=?0.008), low Karnofsky performance score (KPS, P?=?0.02), and large tumor size (P?=?0.01). Moreover, Kaplan-Meier survival and Cox regression analyses showed that low miR-206 expression (P?<?0.001) and advanced pathological grade (P?=?0.02) were independent factors predicting poor prognosis for astrocytomas. In conclusion, this is the first report of the differential expression of miR-206 in human astrocytoma tissues. MiR-206 could be a valuable marker of astrocytoma progression and low miR-206 expression is associated with poor overall survival in patients with malignant astrocytomas.     

microRNA-21 promotes tumor proliferation and invasion in gastric cancer by targeting PTEN

Gastric cancer is one of the most common carcinomas in China. microRNAs, a type of non-coding RNA, are important specific regulators and are involved in numerous bioprocesses of an organism. microRNA-21 (miR-21) has been identified as the most suitable choice for further investigation because it is overexpressed in nearly all solid tumors; furthermore, it has been demonstrated that miR-21 is involved in the genesis and progression of human cancer. It has been reported that PTEN, an important tumour suppressor, is regulated by multiple miRNAs. Thus, in this study we focused on the expression and significance of miR-21 in gastric cancer tissues, and the role of miR-21 in the biological behaviour and the expression of PTEN in gastric cancer cells. Real-time PCR was used to detect miR-21 expression in gastric cancer tissues, the adjacent normal tissues, and the gastric cell lines. The gastric cancer cell line BGC-823 was transfected with pre-miR-21/miR-21 inhibitor to overexpress/downregulate miR-21. The influence of miR-21 on the biological behaviour of gastric cancer cells was evaluated using the CCK-8 kit, FCMs, the scratch healing assay and the transwell test. Western blotting and the Luciferase Reporter Assay were used to evaluate the change of PTEN expression after lowered expression of miR-21 in gastric cancer cell lines. Real-time PCR analysis indicated that miR-21 exhibited higher expression in gastric cancer tissues compared to the adjacent non-tumor tissues. miR-21 expression was significantly associated with the degree of differentiation of the tumour tissues (P=0.004), as well as local invasion and lymph node metastasis (P<0.01). After transfection, pre-miR21 BGC-823 cells grew faster than the negative and control groups (P<0.01). The reduction in miR-21 expression demonstrated a remarkable effect on the biological behaviour of gastric cancer cells (P<0.05); the pre-miR-21-transfected cells healed more quickly compared to the control cells in the scratch healing assay, whereas the transwell test indicated that cell migration in vitro was notably inhibited with the downregulation of miR-21 (P<0.05). The western blot results and Luciferase Reporter Assay demonstrated that PTEN expression was remarkably increased after miR-21 inhibition (P<0.05). microRNA-21 expression was upregulated in gastric carcinoma tissues and was significantly associated with the degree of differentiation of tumour tissues, local invasion and lymph node metastasis. Overexpression of miR-21 promoted BGC-823 cell growth, invasion and cell migration in vitro, whereas downregulation of miR-21 exhibited a stronger inhibitory effect on the biological behaviour of gastric cancer cells; additionally, miR-21 inhibition may upregulate the PTEN expression level, which indicates that PTEN may be a target gene for gastric cancer initiation and development.     

MiR-21 overexpression is associated with acquired resistance of EGFR-TKI in non-small cell lung cancer

Background and purpose

With the increasing use of epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) in patients with advanced non-small cell lung cancer (NSCLC), its acquired resistance has become a major clinical problem. Recent studies revealed that miR-21 was involved into the resistance of cytotoxic agents. The aim of this study was to investigate its role in the acquired resistance of NSCLC to EGFR-TKI.

Methods

EGFR-TKI-sensitive human lung adenocarcinoma cell line PC9 and the acquired resistant cell line, PC9R, were used. Lentiviral vectors were used to infect PC9 or PC9R to regulate the miR-21 expression. The expression of targeted proteins PTEN and PDCD4 was controlled by RNA interference. MicroRNA array, RT-PCR and TaqMan MicroRNA Assays were used to detect miR-21 expression. The MTT and Annexin V assays were used to determine proliferation and apoptosis. Western Blot and immunohistochemistry were used to analyze target protein expression (PTEN, PDCD4, Akt, p-Akt). We also constructed PC9R xenograft tumor model to observe the relationship between miR-21 and EGFR-TKI resistance in vivo and validated it in the clinical serum specimens of NSCLC patients treated with EGFR-TKI.

Result

MiR-21 was overexpressed in the EGFR-TKI resistant cell line PC9R relative to PC9. The level of miR-21 was reversely correlated with the expression of PTEN and PDCD4 and positive correlated with PI3K/Akt pathway. Inhibiting miR-21 with lentivirus vector induces apoptosis in PC9R cell line and inhibiting miR-21with ASO suppressed tumor growth in nude mice treated with EGFR-TKI. Furthermore, serum miR-21 expression in NSCLC patients treated with EGFR-TKI was significantly higher at the time of acquiring resistance than at baseline (p < 0.01).

Conclusion

miR-21 is involved in acquired resistance of EGFR-TKI in NSCLC, which is mediated by down-regulating PTEN and PDCD4 and activating PI3K/Akt pathway.     

RETRACTED ARTICLE: Downregulation of microRNA-217 and microRNA-646 acts as potential predictor biomarkers in progression,metastasis, and unfavorable prognosis of human osteosarcoma

Despite the progress in therapeutic targets, it remains dissatisfactory for most osteosarcoma patients with metastasis or recurrence osteosarcoma. Therefore, it is required to determine the involved mechanisms of osteosarcoma. The aim of this study was to investigate the expression level of MiR-217 and miR-646 and also their association with clinicopathological features in patients with osteosarcoma. Total RNA was purified from patients with osteosarcoma and noncancerous bone tissues, and then quantitative real-time PCR was applied to evaluate the expression level of microRNAs. Our result suggested that miR-217 expression was remarkably deceased in osteosarcoma bone tissue when compared with noncancerous bone tissues (mean?±?SD 5.32?±?1.231, 2.01?±?0.78; P?=?0.024) and miR-646 expression decreased in osteosarcoma bone tissue in comparison with normal tissues (mean?±?SD 4.56?±?1.45, 1.76?±?1.24; P?=?0.041). Our findings indicated that decreased expression of MiR-217 and miR-646 was strongly correlated with high tumor, node, and metastasis (TNM) stage (P?=?0.015, P?=?0.002) and large cancer diameter (P?=?0.041, P?=?0.053). Kaplan-Meier survival and log-rank analysis indicated that shorter overall survival was strongly linked to decreased expression of miR-217 and miR-646 (log-rank test P?=?0.034, P?=?0.026). In terms of miR-217, multivariate Cox proportional hazards model analysis has showed that reduction of miR-217 expression (P?=?0.001), TNM stage (P?=?0.046), and lymph node metastasis (P?=?0.006) were independently linked to a short-time survival of patients. In terms of miR-646, low expression of miR-646 (P?=?0.021), TNM stage (P?=?0.052), and tumor size (P?=?0.043) were independently associated with poor survival of patients as prognostic factors. Our findings suggested that downregulation of MiR-217 and miR-646 was associated with progression of osteosarcoma. MiR-217 and miR-646 may play a key role in suppression of tumor in osteosarcoma and would be applied as a novel therapeutic agent.     

miRNA-21 regulates arsenic-induced anti-leukemia activity in myelogenous cell lines

MicroRNAs (miRNAs) are endogenous small noncoding RNA molecules involved in modulation of cellular sensitivity to anti-cancer drugs. miRNA-21 (miR-21), one of the most prominent miRNAs in the genesis and progression of many human cancers, has been rarely characterized in myelogenous leukemia. Arsenic trioxide (ATO) was successfully used in the treatment of acute promyelocytic leukemia (APL) etc. However, cytotoxicity or insensitivity is a major concern in the successful treatment of leukemia. Here, we used a specific precursor miRNA-21 (pre-miR-21) or anti-miRNA-21 oligonucleotide (AMO-miR-21) to study sensitivity of HL60 and K562 cells to ATO. Cell viability and cell cycle were evaluated by MTT assay and PI assay using flow cytometry, respectively. Levels of miR-21 and its target PDCD4 were quantified by real-time PCR and/or western blot. AMO-miR-21 or ATO alone led to growth inhibition, apoptosis and G1 phase arrest of cell cycle. Apoptotic cells were confirmed morphologically with Hoechst staining. Moreover, there was somewhat synergistic effect of AMO-miR-21 and ATO in growth inhibition and apoptosis promotion. Meanwhile, enforced pre-miR-21 expression increased resistance to ATO, nevertheless not affecting cell growth alone. Dual-luciferase reporter vector containing two tandem PDCD4 3′ UTR validated that PDCD4 was directly up-regulated by miR-21. Therefore, miRNA-21 by targeting PDCD4 may play a functional role in modulating ATO-induced cell death, and strategy using AMO-miR-21 and its combination with ATO may be useful as a myelogenous leukemia therapy.     

Loss of E-cadherin promotes migration and invasion of cholangiocarcinoma cells and serves as a potential marker of metastasis

Tumor progression is characterized by loss of cell adhesion and increase of invasion and metastasis. E-cadherin, a cell adhesion molecule, is frequently downregulated and has been proposed as an important mediator in epithelial-mesenchymal transition (EMT) in tumors. In this study, we investigated the expression of E-cadherin and its association with cancer invasion and prognosis in cholangiocarcinoma (CCA). Immunohistochemistry results demonstrated a statistically significant association between the positive metastasis status with low E-cadherin protein expression in human CCA tissues (P?=?0.04). Statistical trends were identified for low E-cadherin level and shorter survival time (P?=?0.08). Targeting the E-cadherin expression in CCA cells with siRNA caused upregulation of vimentin, a mesenchymal marker, and disappearance of the E-cadherin/β-catenin adhesion complex from cell membranes. Moreover, migration and invasion abilities of the cells were increased under this condition. These findings suggest that reduction of E-cadherin contributes to CCA progression by attenuating the strength of cellular adhesion, which affects motility as well as regulating the expression of EMT-related genes during CCA invasion and metastasis. Thus, E-cadherin can act as a central modulator of tumor cell phenotype and is a potential metastasis marker in CCA.     

下调miR-21对PDCD4表达及结肠癌HT-29细胞功能的影响研究

背景与目的：miR-21可能通过抑制PDCD4表达调控结肠癌浸润及转移等恶性行为。本研究通过下调miR-21表达后,检测结肠癌HT-29细胞功能的变化,并观察PDCD4在蛋白及mRNA表达水平的改变,探讨miR-21及PDCD4的表达在结肠癌恶性行为中的关系及机制。方法：构建靶向miR-21的干扰质粒simiR-21,转染HT-29细胞后,以实时定量PCR(qRT-PCR)法检测转染效率,MTT法检测转染后细胞增殖变化,流式细胞术检测转染后细胞调亡变化,Transwell检测迁移及浸润能力改变,蛋白质印迹法(Western blot)及qRT-PCR法检测干扰后PDCD4表达水平变化。结果：经qRT-PCR检测simiR-21在HT-29细胞转染效率为60%～65%,转染效率佳;MTT显示转染后72、96和120 h,HT-29增殖能力减弱(t=1.276,P<0.05;t=3.276,P<0.01;t=4.523,P<0.01);流式细胞术结果显示,与si-negative control及miR-21组对比转染后HT-29调亡率明显增加(t=2.132,P<0.05;t=3.524,P<0.05);Transwell结果显示,simiR-21转染细胞迁移能力降低(t=2.423,P<0.05;t=3.153,P<0.05),侵袭能力降低(t=3.245,P<0.05;t=5.236,P<0.05);Western blot检测结果显示,PDCD4蛋白在simiR-21细胞的表达水平明显上调(t=2.342,P<0.05;t=4.215,P<0.05);qRT-PCR检测结果显示,PDCD4 mRNA在simiR-21细胞的表达水平明显上调(t=2.261,P<0.05;t=3.492,P<0.05)。结论：simiR-21下调miR-21表达后,结肠癌HT-29细胞增殖能力受抑制,并促进其调亡,抑制迁移及浸润能力,PDCD4上调。miR-21可能通过下调PDCD4表达促进肿瘤细胞恶性行为,可作为结肠癌治疗新的靶向候选基因。     

RETRACTED ARTICLE: Downregulation of miR-148b as biomarker for early detection of hepatocellular carcinoma and may serve as a prognostic marker

MicroRNAs (miRNAs) have a large number of various target genes in different cancer types, which may result in many biological functions. Thus, identifying the molecular mechanisms of miRNAs may effect on the complexity of cancer progression via regulation of gene. In the current study, we utilized real-time PCR to quantify the diction of miR-148b in trail hepatocellular carcinoma (HCC) specimen and normal tissues. Furthermore, we evaluated the relationship of miR-148b and clinicopathological features with survival of HCC patients. Therefore, we evaluated the level of miR-148b expression in 101 HCC patients and also in 40 normal control cases. The result suggested lower expression in tumor tissues than normal control tissues (0.96?±?0.14; 1.84?±?0.20, P?<?0.05). Our findings suggest that the declined expression of miR-148b can considerably be linked to tumor node metastasis (TNM) stage (stages III and IV; P?=?0.021) and vein invasion (P?=?0.029). Nevertheless, miR-148b expression was not related to sex (P?=?0.674), age (P?=?0. 523), size of tumor (P?=?0.507), liver cirrhosis, and histologic grade (P?=?0.734). Survival analysis showed that low expression was remarkably related to overall survival (P?=?0.012). Furthermore, multivariate survival test suggested that decline of miR-148b diction was linked to poor survival in HCC patients. Our results suggested that miR-148b is decreased in HCC. Therefore, we concluded that miR-148b may play its role in the prognosis of HCC.