Overexpression of secretagogin inhibits cell apoptosis and induces chemoresistance in small cell lung cancer under the regulation of miR-494

Secretagogin (SCGN) has recently been identified to play a crucial role in cell apoptosis, receptor signaling and differentiation. However, its clinical significance and functional roles in SCLC chemoresistance remain unknown. Here we examined the expression of SCGN in clinical samples from SCLC patients and evaluated its relation with clinical prognosis. Then up and down-regulation of SCGN were carried out in SCLC cell lines to assess its influence on chemoresistance. Furthermore, luciferase reporter assay was used to evaluate whether SCGN is a novel direct target of miR-494. Our results revealed that elevated expression of SCGN was correlated with the poorer prognosis of SCLC patients and the more significant correlation with chemosensitivity. We also found that knockdown of SCGN expression in H69AR and H446AR cells increased chemosensitivity via increasing cell apoptosis and cell cycle arrest of G0/G1 phase, while over-expression of SCGN reduced chemosensitivity in sensitive H69 and H446 cells. SCGN as a novel target of miR-494 by luciferase reporter assay, up-regulation of miR-494 can sensitize H69AR cells to chemotherapeutic drugs. These results suggest SCGN is involved in the chemoresistance of SCLC under the regulation of miR-494 and may be a potential biomarker for predicting therapeutic response in treatment SCLC.     

Anti-miR21 oligonucleotide enhances chemosensitivity of T98G cell line to doxorubicin by inducing apoptosis

Various signal transduction pathways seem to be involved in chemoresistance mechanism of glioblastomas (GBMs). miR-21 is an important oncogenic miRNA which modulates drug resistance of tumor cells. We analyzed the expression of 5 miRNAs, previously found to be dysregulated in high grade gliomas, in 9 pediatric (pGBM) and in 5 adult (aGBM) GBMs. miR-21 was over-expressed, with a significant difference between pGBMs and aGBMs represented by a 4 times lower degree of expression in the pediatric compared to the adult series (p = 0.001). Doxorubicin (Dox) seems to be an effective anti-glioma agent with high antitumor activity also against glioblastoma stem cells. We therefore evaluated the chemosensitivity to Dox in 3 GBM cell lines (A172, U87MG and T98G). Dox had a cytotoxic effect after 48 h of treatment in A172 and U87MG, while T98G cells were resistant. TUNEL assay verified that Dox induced apoptosis in A172 and U87MG but not in T98G. miR-21 showed a low basal expression in treated cells and was over-expressed in untreated cells. To validate the possible association of miR-21 with drug resistance of T98G cells, we transfected anti-miR-21 inhibitor into the cells. The expression level of miR-21 was significantly lower in T98G transfected cells (than in the parental control cells). Transfected cells showed a high apoptotic rate compared to control after Dox treatment by TUNEL assay, suggesting that combined Dox and miR-21 inhibitor therapy can sensitize GBM resistant cells to anthracyclines by enhancing apoptosis.     

Interaction between CD44 and hyaluronate induces chemoresistance in non-small cell lung cancer cell

CD44s is a principle hyaluronate (HA) receptor and has been reported to play an important role in cancer cell invasion and metastasis. The aim of our study is to determine if the interaction between HA and CD44s influences in vitro chemosensitivity of non-small cell lung cancer (NSCLC). NSCLC cell line, H322 cells, transfected with the CD44s gene (H322/CD44s) cultured on HA coated plates were more resistant to cisplatin (CDDP) than that on bovine serum albumin. Multidrug resistance protein2 (MRP2) expression was induced in H322/CD44s cells cultured on HA. MRP2 inhibitor, MK571, not only suppressed MRP2 expression but also reversed CDDP resistance. These results suggest that the interaction between CD44s and HA play a pivotal role in acquired resistance to CDDP in NSCLC and MRP2 could be involved in this potential mechanism.     

miR-21调控程序性细胞死亡4基因的表达对宫颈癌细胞增殖和侵袭能力的影响

目的:探讨miR-21调控程序性细胞死亡4基因的表达对宫颈癌细胞增殖和侵袭能力的影响及其 机制。方法:qPCR检测miR-21和PDCD4在宫颈癌组织中的表达情况;双荧光素酶实验检测miR-21和PDCD4之间的调控作用;细胞集落实验检测抑制miR-21对宫颈癌细胞增殖能力的影响情况,Transwell侵袭实验检测对宫颈癌细胞侵袭能力的影响情况。结果:与癌旁正常组织相比,miR-21在宫颈癌组织中的表达上调,PDCD4在宫颈癌组织中表达下调;双荧光素酶实验检测miR-21和PDCD4之间的调控关系,miR-21可直接调控PDCD4蛋白的表达及活性情况;抑制miR-21的表达后可以抑制宫颈癌细胞的增殖能力;抑制miR-21的表达水平后,宫颈癌细胞的侵袭能力得到一定程度的抑制。结论:miR-21可以调控PDCD4的表达影响宫颈癌细胞的增殖和侵袭能力。     

miR-21通过靶向PDCD4调控三阴性乳腺癌细胞的迁移和侵袭

目的： 研究miR-21在三阴性乳腺癌细胞MDA-MB-231中的表达，以及其是否通过调控PDCD4影响MDA-MB-231细胞的迁移和侵袭。方法： 采用实时定量PCR（qPCR）法检测MDA-MB-231细胞和正常乳腺细胞MCF-10A中miR-21和PDCD4 mRNA的表达。将MDA-MB-231细胞随机分为5组：空白对照组，转染miR-21模拟物组，模拟物对照组，转染miR-21抑制物组和抑制物对照组。采用Western blot法检测MDA-MB-231细胞PDCD4蛋白的表达；采用荧光素酶报告基因试剂盒检测转染不同载体后荧光强度的变化来判断miR-21的靶标；采用Transwell实验检测各组细胞的迁移和侵袭数目。结果： miR-21和PDCD4 mRNA在MDAMB-231细胞中的表达水平分别明显高于和低于MCF-10A细胞（P均 < 0.01）。过表达或抑制miR-21可调节PDCD4的表达水平。荧光素酶报告基因试剂盒检测结果显示miR-21可直接靶向调控PDCD4的表达。Transwell实验结果表明过表达miR-21表达能增强MDA-MB-231细胞的迁移和侵袭能力。结论： 在MDA-MB-231细胞中，miR-21通过靶向调控PDCD4表达影响细胞的迁移和侵袭。miR-21可能成为抑制三阴性乳腺癌迁移和侵袭的靶点。     

miR-21通过靶向PDCD4调控三阴性乳腺癌细胞的迁移和侵袭

目的： 研究miR-21在三阴性乳腺癌细胞MDA-MB-231中的表达,以及其是否通过调控PDCD4影响MDA-MB-231细胞的迁移和侵袭。方法： 采用实时定量PCR（qPCR）法检测MDA-MB-231细胞和正常乳腺细胞MCF-10A中miR-21和PDCD4 mRNA的表达。将MDA-MB-231细胞随机分为5组：空白对照组,转染miR-21模拟物组,模拟物对照组,转染miR-21抑制物组和抑制物对照组。采用Western blot法检测MDA-MB-231细胞PDCD4蛋白的表达;采用荧光素酶报告基因试剂盒检测转染不同载体后荧光强度的变化来判断miR-21的靶标;采用Transwell实验检测各组细胞的迁移和侵袭数目。结果： miR-21和PDCD4 mRNA在MDAMB-231细胞中的表达水平分别明显高于和低于MCF-10A细胞（P均 < 0.01）。过表达或抑制miR-21可调节PDCD4的表达水平。荧光素酶报告基因试剂盒检测结果显示miR-21可直接靶向调控PDCD4的表达。Transwell实验结果表明过表达miR-21表达能增强MDA-MB-231细胞的迁移和侵袭能力。结论： 在MDA-MB-231细胞中,miR-21通过靶向调控PDCD4表达影响细胞的迁移和侵袭。miR-21可能成为抑制三阴性乳腺癌迁移和侵袭的靶点。     

microRNA-21 modulates cell proliferation and sensitivity to doxorubicin in bladder cancer cells

Transitional cell carcinomas (TCCs) of the urinary bladder are common malignancies with a high recurrence rate. Since microRNA-21 (miR-21) may contribute to tumorigenesis and chemoresistance in many cancer types, we aimed to investigate its efficacy in TCCs. The expression of miR-21 and its target PTEN was determined by real-time qRT-PCR and western blotting, respectively in tumor tissues as well as adjacent non-tumor mucosa. The effect of miR-21 on cell proliferation and chemosensitivity to doxorubicin were measured using the MTT method. Cell apoptosis induced by doxorubicin was investigated using flow cytometry in the T24 cell line. BCL-2, AKT and pAKT were detected by western blotting for analysis of potential mechanisms. miR-21 was significantly up-regulated in tumor tissues while PTEN was expressed in lower levels compared to non-tumor tissues. A negative correlation between expression of miR-21 and PTEN was established in vivo. Cell proliferation and chemoresistance to doxorubicin were promoted by overexpression of miR-21 in T24 cells. BCL-2 up-regulation could be achieved by miR-21 overexpression, which prevented T24 cells from apoptosis induced by doxorubicin. Furthermore, the miR-21 induced BCL-2 up-regulation could be cancelled by the PI3K inhibitor LY294002. These data verified the oncogenic role of miR-21 in TCCs and may usher in new therapeutic strategies in treating this disease.     

肿瘤干细胞标志物CD133-2、CD24和CD44S在头颈部鳞状细胞癌组织中的表达及其临床意义

 目的　探讨肿瘤干细胞标志物CD133-2、CD24、CD44S在头颈部鳞状细胞癌（HNSCC）组织中的表达情况及其临床意义。方法　采用免疫组织化学SP法,分别检测83例HNSCC患者癌组织、46例癌旁正常鳞状上皮组织中CD133-2、CD24、CD44S的表达,分析表达情况及与临床病理特征的关系。结果　CD133-2在癌组织、癌旁正常鳞状上皮组织中表达率分别为9.64 %（8／83）、21.74 %（10／46）,CD24分别为90.36 %（75／83）、45.65 %（21／46）,差异均有统计学意义（χ2值分别为15.040、5.818,均P＜0.05）;CD44S在癌组织、癌旁正常组织中均表达,但其染色评分差异有统计学意义（Z＝-4.262,P＜0.05）。在癌组织中,CD133-2的表达与组织的分化程度呈负相关（χ2＝7.246,P＜0.05）,CD24和CD44S的表达均与组织的分化程度呈正相关（χ2值分别为9.005、44.765,均P＜0.05）,CD44S的表达与T分期呈负相关（χ2＝4.650,P＜0.05）。结论　CD24、CD44S在HNSCC中的表达随着肿瘤细胞的分化程度增高而增高,能否作为HNSCC的肿瘤干细胞标志物尚需进一步研究;CD133-2表达随肿瘤细胞的分化程度增高而呈下调趋势,可以作为肿瘤干细胞的标志物,并可能与肿瘤的进展、临床预后相关。     

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)。     

miR-21与舌鳞癌SCC9细胞干细胞样特性及顺铂敏感性的实验研究

目的 观察舌鳞癌SCC9细胞干细胞样特性、顺铂敏感性以及miR-21表达对其影响。方法 选取人舌鳞癌SCC9细胞分别通过贴壁、悬浮培养法培养获得SCC9a和SCC9f细胞;体外转染法将miR-21 mimics、miR-21 inhibitor分别转染至SCC9f细胞,设为SCC9m和SCC9i细胞。实时荧光定量PCR（QPCR）法检测干细胞相关转录因子（Oct3／4、Sox2、Nanog）及miR-21表达水平,ALDEFLOR kit检测ALDH阳性细胞的比例。MTT法、Annexin V／PI双染法分别检测顺铂对舌鳞癌细胞增殖及凋亡的影响。结果 SCC9f细胞中Oct3／4、Sox2和Nanog表达以及ALDH阳性比例高于SCC9a细胞（P＜0.05）。顺铂对SCC9f细胞的增殖抑制率、凋亡率均低于SCC9a细胞。miR-21表达在SCC9f细胞中高于SCC9a细胞（P＜0.05）,而在SCC9m、SCC9i细胞中表达分别较SCC9f细胞明显升高与降低（均P＜0.05）。Oct3／4、Sox2和Nanog在SCC9m细胞中表达高于SCC9f细胞,其中Oct3／4上调差异具有统计学意义（P＜0.001）;而Oct3／4、Sox2和Nanog在SCC9i细胞中表达均较SCC9f细胞呈显著下调（P＜0.05）。SCC9a、SCC9m和SCC9i细胞中ALDH阳性率分别与SCC9f细胞中ALDH阳性率比较,差异均有统计学意义（P＜0.05）。SCC9m、SCC9i细胞的凋亡率分别较SCC9f减低与增高（均P＜0.05）。结论 舌鳞癌SCC9细胞采用悬浮培养法培养获得的SCC9f细胞具有干细胞特性,对顺铂更为耐受;抑制miR-21表达可增强SCC9细胞对顺铂的敏感性,可能与miR-21调节其肿瘤干细胞相关转录因子表达有关。     

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.     

Downregulation of MicroRNA-147 Inhibits Cell Proliferation and Increases the Chemosensitivity of Gastric Cancer Cells to 5-Fluorouracil by Directly Targeting PTEN

Gastric cancer is the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. This study aimed to investigate the expression patterns, biological roles, and underlying mechanisms of microRNA-147 (miR-147) in gastric cancer. The present study demonstrated that miR-147 was significantly upregulated in gastric cancer tissues and cell lines. Downregulation of miR-147 decreased cell proliferation and enhanced the chemosensitivity of gastric cancer cells to 5-fluorouracil (5-FU) through the cell apoptosis pathway. In addition, phosphatase and tensin homolog (PTEN) was mechanically identified as the direct target of miR-147 in gastric cancer. PTEN knockdown reversed the effects of miR-147 downregulation on the proliferation, chemosensitivity, and 5-FU-induced apoptosis of gastric cancer cells. Moreover, miR-147 regulated the PI3K/AKT signaling pathway in gastric cancer by targeting PTEN. In conclusion, miR-147 suppressed the proliferation and enhanced the chemosensitivity of gastric cancer cells to 5-FU by promoting cell apoptosis through directly targeting PTEN and regulating the PI3K/AKT signaling pathway. This study provides important insight into the molecular mechanism that underlies the chemoresistance of gastric cancer cells. The results of this study could aid the development of a novel therapeutic strategy for gastric cancer.     

miR-21与肾癌转移的相关性及其对肾癌细胞侵袭能力的影响

  目的   探讨miR-21与肾癌转移的相关性, 及miR-21对肾癌Caki-1细胞侵袭能力的影响。   方法  实时PCR检测原发未转移肾癌和原发伴转移肾癌组织中miR-21的表达。将miR-21的前体pre-miR-21和抑制物anti-miR-21分别转染肾癌Caki-1细胞, 实时PCR验证转染效果, 然后检测转染后细胞的侵袭能力。   结果  与原发未转移肾癌相比, 原发伴转移肾癌组织中miR-21的表达显著上调; pre-miR-21和anti-miR-21转染后能够显著升高和降低Caki-1细胞miR-21的表达量; pre-miR-21组穿透滤膜的细胞数明显增加, 而anti-miR-21组穿透滤膜的细胞数明显减少。   结论  miR-21与肾癌的侵袭转移相关, miR-21能够促进肾癌细胞侵袭, 在肾癌中具有促进转移的作用。      

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。     

Overexpression of microRNA-21 regulating PDCD4 during tumorigenesis of liver fluke-associated cholangiocarcinoma contributes to tumor growth and metastasis

MicroRNA, an endogenous noncoding RNA modulating gene expression, is a key molecule that by its dysregulation plays roles in inflammatory-driven carcinogenesis. This study aimed to investigate the role of oncomiR miR-21 and its target, the programmed cell death 4 (PDCD4) in tumor growth and metastasis of the liver fluke Opisthorchis viverrini-associated cholangiocarcinoma (CCA). The expression levels of miR-21 and PDCD4 were analyzed using the TaqMan miRNA expression assay and immunohistochemistry in liver tissues of both O. viverrini plus N-nitrosodimethylamine (NDMA)-treated hamsters and human CCA samples (n?=?23 cases). The functional assay for miR-21 was performed in CCA cell lines by the anti-miR-21 and pre-miR-21 transfection procedures. The peak of miR-21 levels were reached at 2 (hyperplastic lesions) and 6 (CCA)?months of the O. viverrini plus NDMA-induced group and had a reverse response with its target PDCD4 proteins. In human CCA, miR-21 was overexpressed in tumor tissues when compared with nontumor tissues (P?=?0.0034) and had a negative correlation with PDCD4 protein (P?=?0.026). It was also found that high expression of miR-21 was significantly correlated with shorter survival (P?<?0.05) and lymph node metastasis (P?=?0.037) of CCA patients. Transient transfection of pre-miR-21 reduced the PDCD4 level and resulted in an increase of M213 CCA cell growth and wound-induced migration ability. These results indicated that miR-21 plays a role in the carcinogenesis and metastasis of O. viverrini-associated CCA by suppressing the function of PDCD4. Modulation of aberrantly expressed miR-21 may be a useful strategy to inhibit tumor cell phenotypes or improve response to chemotherapy.     

MicroRNA-21 promotes cell transformation by targeting the programmed cell death 4 gene

MicroRNAs (miRNAs) are small noncoding RNA molecules that negatively control expression of target genes in animals and plants. The microRNA-21 gene (mir-21) has been identified as the only miRNA commonly overexpressed in solid tumors of the lung, breast, stomach, prostate, colon, brain, head and neck, esophagus and pancreas. We initiated a screen to identify miR-21 target genes using a reporter assay and identified a potential miR-21 target in the 3'-UTR of the programmed cell death 4 (PDCD4) gene. We cloned the full-length 3'-UTR of human PDCD4 downstream of a reporter and found that mir-21 downregulated, whereas a modified antisense RNA to miR-21 upregulated reporter activity. Moreover, deletion of the putative miR-21-binding site (miRNA regulatory element, MRE) from the 3'-UTR of PDCD4, or mutations in the MRE abolished the ability of miR-21 to inhibit reporter activity, indicating that this MRE is a critical regulatory region. Western blotting showed that Pdcd4 protein levels were reduced by miR-21 in human and mouse cells, whereas quantitative real-time PCR revealed little difference at the mRNA level, suggesting translational regulation. Finally, overexpression of mir-21 in MCF-7 human breast cancer cells and mouse epidermal JB6 cells promoted soft agar colony formation by downregulating Pdcd4 protein levels. The demonstration that miR-21 promotes cell transformation supports the concept that mir-21 functions as an oncogene by a mechanism that involves translational repression of the tumor suppressor Pdcd4.