MiR-16-1 Targeted Silences Far Upstream Element Binding Protein 1 to Advance the Chemosensitivity to Adriamycin in Gastric Cancer

Chemotherapy can prevent metastasis and recurrence of gastric cancer (GC), and is a well supplement for operation. But, chemotherapy resistance has severely restricted the application of chemotherapy. This study aimed to investigate the regulatory roles and molecular mechanism of miR-16-1 to the chemosensitivity to adriamycin in GC. In this study, the expression of miR-16-1 and FUBP1 was down-regulated and up-regulated respectively in adriamycin-resistant GC tissues and cell lines, and represented a negative relationship between them. MiR-16-1 could silence FUBP1 directly and specifically, FUBP1 was a target gene of miR-16-1. Silence of FUBP1 inhibited the half maximal inhibitory concentration (IC50) of SGC7901/AR cell line to adriamycin, chemosensitivity enhanced significantly. Moreover, FUBP1 silence in SGC7901/AR cell line also inhibited proliferation and invasion, and advanced cell apoptosis. To sum up, the expression of miR-16-1 was positively related with the chemosensitivity of GC to adriamycin, and miR-16-1 could targeted silence FUBP1 to advance the chemosensitivity to adriamycin in GC, which might be a novel potential therapeutic target for GC.     

CircBAGE2 (hsa_circ_0061259) regulates CCND1 and PDCD10 expression by functioning as an miR-103a-3p'sponge'to alter the proliferation and apoptosis of prostate cancer cells

Objective The aim of the article is to explore the function of circBAGE2 (hsa_circ_0061259) in prostate cancer (PCa) cells. Methods Sequencing results of circBAGE2 were verified by quantitative RT PCR (qRT-PCR) and Sanger sequencing. Agarose gel electrophoresis was used to detect the resistance of GAPDH, BAGE2, and circBAGE2 to RNase R and their expression as cDNA and gDNAin 22RV1 cells. The biological functions of circBAGE2 were investigated by CCK8 assay and flow cytometry in 22RV1 cells transfected with siRNAs. Multiple databases were used to predict the target binding sites between circRNAs, miRNAs, and mRNAs. Western blotting was used to detect the expression of CCND1 and PDCD10. Results CircBAGE2 was significantly upregulated in PCa samples and PCa cells compared to that in matched normal tissues and normal cells, and CircBAGE2 knockdown inhibits cell proliferation and promotes apoptosis. Downregulation of circBAGE2 compromised the expression of CCND1 and PDCD10. The 3' UTRs of CCND1 and PDCD10 were matched by miR-103a-3p, which shared binding sites with circBAGE2. Conclusion CircBAGE2 contributes to PCa progression by upregulating CCND1 and PDCD10 expression through its role as a 'sponge' of miR-103a-3p. CircBAGE2 may be a potential therapeutic target for PCa.     

miR-361-5p通过靶向CCND1逆转胃癌SGC-7901细胞奥沙利铂耐药性

目的:探讨miR-361-5p对胃癌SGC-7901细胞奥沙利铂(oxaliplatin,OXA)耐药性的影响及其作用机制.方法:采用qPCR法检测miR-361-5p在胃癌细胞MKN-45、MGC80-3、SGC-7901和OXA耐药细胞SGC-7901/OXA中的表达水平.利用脂质体转染技术分别将miR-361-5...     

MicroRNA 495 Inhibits Proliferation and Metastasis and Promotes Apoptosis by Targeting Twist1 in Gastric Cancer Cells

Recently, microRNAs (miRNAs) have been reported to participate in multiple biological processes. However, the effects of miR-495 on gastric cancer (GC) remain unclear. The purpose of this study was to explore the functions of miR-495 in GC cell proliferation, metastasis, and apoptosis. SGC-7901 and BGC-823 cell lines were transfected with miR-495 mimic, miR-495 inhibitor, and negative controls (mimic control and inhibitor control). The expressions of miR-495, cell viability, migration, apoptosis, and apoptosis-related factors were examined by qRT-PCR, trypan blue staining, Transwell, flow cytometry, and Western blot, respectively. Simultaneously, key factor expression levels of EMT were detected by qRT-PCR and Western blot. The direct target of miR-495 was confirmed by dual-luciferase assay. Additionally, sh-Twist1, pc-Twist1, and corresponding controls were transfected into SGC-7901 and BGC-823 cells, and the protein levels of EMTassociated factors were detected by Western blot. miR-495 was downregulated in GC cells. miR-495 expression level was effectively overexpressed or suppressed in SGC-7901 and BGC-823 cells. Overexpression of miR-495 significantly decreased cell viability and migration, increased apoptosis, and inhibited the EMT process. Suppression of miR-495 showed contrary results. Twist1 was clarified as a target gene of miR-495, and Twist1 silencing obviously reduced the promoting effect of miR-495 suppression on these biological processes. Twist1 silencing significantly blocked the EMT process in both SGC-7901 and BGC-823 cells. miR-495 inhibited proliferation and metastasis and promoted apoptosis by targeting Twist1 in GC cells. These data indicated that miR-495 might be a novel antitumor factor of GC and provide a new method for the treatment of GC.     

Upregulation of microRNA-181a-5p increases the sensitivity of HS578T breast cancer cells to cisplatin by inducing vitamin D receptor-mediated cell autophagy

Breast cancer (BC) is the leading cause of death in females worldwide. Although cisplatin is a strong-effect and broad-spectrum chemotherapy drug, resistance to cisplatin remains a significant factor effecting clinical efficacy. The underlying mechanism of cancer cell resistance to cisplatin is not fully understood. MicroRNAs (miRs/miRNAs), as a regulator, are involved in regulating chemosensitivity to numerous chemotherapeutic drugs. The present study aimed to investigate the function of miR-181a-5p as a potential tumor suppressor in improving the efficiency of cisplatin in BC. The IC₅₀ of cisplatin and miR-181a-5p expression were determined in five BC cell lines, and HS578T was selected as an appropriate cell line for subsequent experiments. The sensitivity of HS578T cells to cisplatin was assessed using cell proliferation, migration and apoptosis assays. Western blotting was performed to detect the expression of vitamin D receptor (VDR) and autophagy in HS578T cells. It was found that the increase in autophagy resulted in increased apoptosis and sensitivity to cisplatin in HS578T cells. miR-181a-5p transfection also inhibited the proliferation and migration ability of HS578T cells and induced apoptosis. Meanwhile, HS578T cells have increased sensitivity to cisplatin. VDR, as a target gene and autophagy regulator of miR-181a-5p, was negatively regulated by miR-181a-5p. Upon the decrease in VDR expression, the autophagy in HS578T cells was increased. These results indicate that the increase in autophagy enhanced the chemosensitivity of cisplatin by inducing apoptosis of HS578T cells and by inhibiting proliferation and migration. The present study showed that miR-181a-5p increased the chemical sensitivity of HS578T cells to cisplatin by inhibiting VDR to promote autophagy. The use of miR-181a-5p/autophagy/VDR-based treatment strategies may be a potential method to overcome cisplatin resistance in BC.     

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-488 acts as a tumor suppressor gene in gastric cancer

MicroRNAs (miRNAs) are small, non-coding RNAs that modulate development, cell proliferation, and apoptosis. The deregulated expression of microRNAs is found in carcinogenesis including gastric cancer (GC). In this study, we showed that the expression levels of miR-488 were downregulated in GC tissues compared to in non-tumor tissues. In addition, the expression of miR-488 was also lower in GC cell lines in contrast with the gastric epithelial cell line (GES). In addition, the expression level of miR-488 was negatively correlated with the TNM stage in GC patients, and lower miR-488 expression was found in tumors with advanced TNM stage. The ectopic expression of miR-488 suppressed the GC cell proliferation, cell cycle, colony information, and migration. PAX6 was identified as a direct target gene of miR-488 in HGC-27. Moreover, we found that the expression level of PAX6 was upregulated in the GC tissues compared with the non-tumor tissues. The PAX6 expression level was correlated with the cancer TNM stage, and higher PAX6 expression was found in tumors with advanced TNM stage. Furthermore, there was an inverse correlation between PAX6 and miR-488 expression levels in GC tissues. Therefore, these studies demonstrated that miR-488 might act as a tumor suppressor miRNA in the development of GC.     

MicroRNA-664 Targets Insulin Receptor Substrate 1 to Suppress Cell Proliferation and Invasion in Breast Cancer

A large number of microRNAs (miRNAs) have been previously demonstrated to be dysregulated in breast cancer (BC), and alterations in miRNA expression may affect the initiation and progression of BC. This study showed that miR-664 expression was obviously reduced in BC tissues and cell lines. Resumption of the expression of miR-664 attenuated the proliferation and invasion of BC cells. The molecular mechanisms underlying the inhibitory effects of BC cell proliferation and invasion by miR-664 were also studied. Insulin receptor substrate 1 (IRS1) was identified as a novel and direct target of miR-664. In addition, siRNAmediated silencing of IRS1 expression mimicked the suppressive effects of miR-664 overexpression in BC cells. Rescue experiments demonstrated that recovered IRS1 expression partially antagonized the inhibition of proliferation and invasion of BC cells caused by miR-664 overexpression. Thus, miR-664 may serve as a tumor suppressor in BC by directly targeting IRS1. Moreover, miR-664 downregulation in BC may contribute to the occurrence and development of BC, suggesting that miR-664 may be a novel therapeutic target for patients with BC.     

miR-106b-5p靶向调控细胞周期蛋白D1抑制结直肠癌细胞增殖、迁移与侵袭

目的:探讨miR-106b-5p对结直肠癌(colorectal cancer,CRC)细胞增殖、迁移与侵袭的影响以及其作用机制.方法:实时荧光定量PCR检测miR-106b-5p在CRC组织与相应的癌旁组织、永生化的肠上皮细胞以及肠癌细胞中的表达量;CCK8实验检测DLD1细胞增殖能力;细胞划痕实验检测DLD1细胞的...     

Down-regulation of c-Met and Bcl2 by microRNA-206, activates apoptosis,and inhibits tumor cell proliferation,migration and colony formation

Hsa-miRNA-206 (miR-206), highly expressed in skeletal muscle, has recently been discovered to have anticancer properties in different tissues. However, the role of miR-206 on lung cancer is still ambiguous. In this study, we investigated the role of miR-206 on the development of lung cancer. The results indicated that miR-206 expression was suppressed in lung cancer tissues and very low levels were found in non-small cell lung cancer (NSCLS) cell liness. Transient transfection of miR-206 into cultured A549 and SK-MES-1 cells led to significant decrease in cell growth, migration, invasion and colony formation, and promoted cell apoptosis. Using bioinformatics, we identified putative miR-206 binding sites within the 3′-untranslated region (3′-UTR) of the human c-Met and Bcl2 mRNA. The expression of c-Met and Bcl2 proteins were shown to be down-regulated after treated with miR-206 by subsequent Western blot and qRT-PCR analysis. Conversely, up-regulation of c-Met and Bcl2 were confirmed in tissue samples of human lung cancer, with its level inversely correlated with miR-206 expression. In addition, miR-206 also decreased the gene expression of MMP-9, CCND1 and CCND2 while increased the gene expression of p57 (Kip2) in A549 and SK-MES-1 cells. Taken together, our results demonstrated that miR-206 suppressed c-Met and Bcl2 expression in NSCLS and could function as a potent tumor suppressor in c-Met/Bcl2-over expressing tumors. Inhibition of miR-206 function could contribute to aberrant cell proliferation, migration, invasion and apoptosis, leading to NSCLS development.     

微小RNA-30a:肿瘤治疗的潜在靶点

微小RNA(miRNA)是长约20~25个核苷酸的内源性非编码RNA,主要通过抑制mRNA翻译和诱导mRNA降解而调节靶基因的表达,人类大约30%的基因受miRNAs调节。研究发现,大量miRNAs在肿瘤中表达失调,常常引起多种重要过程的紊乱,包括细胞增殖、侵袭与转移、凋亡以及耐药等。在肿瘤的发生过程中,不同的miRNA可能起着类似抑癌基因或者癌基因的作用,参与调节肿瘤细胞发生、发展等过程。miR-30a是miRNA的成员之一,通过调节靶基因的表达,参与调控肿瘤细胞增殖、转移和凋亡等过程。不同肿瘤血清中miR-30a的表达水平对肿瘤的早期诊断、治疗以及预后判断有着重要作用。此外,miR-30a的表达失调还与抗肿瘤药物耐药性的产生密切相关,推测其有望成为肿瘤治疗的一个潜在新靶标。本文就近年来miR-30a在肿瘤中作用的最新研究进展作一综述。     

MiR-101 inhibits cell growth and tumorigenesis of Helicobacter pylori related gastric cancer by repression of SOCS2

Several microRNAs (miRNA) have been implicated in H. pylori related gastric cancer (GC). However, the molecular mechanism of miRNAs in gastric cancer has not been fully understood. In this study, we reported that miR-101 is significantly down-regulated in H. pylori positive tissues and cells and in tumor tissues with important functional consequences. Ectopic expression of miR-101 dramatically suppressed cell proliferation and colony formation by inducing G1-phase cell-cycle arrest. We found that miR-101 strongly reduced the expression of SOCS2 oncogene in GC cells. Similar to the restoring miR-26 expression, SOCS2 down-regulation inhibited cell growth and cell-cycle progression, whereas SOCS2 over-expression rescued the suppressive effect of miR-101. Mechanistic investigations revealed that miR-101 suppressed the expression of c-myc, CDK2, CDK4, CDK6, CCND2, CCND3, and CCNE2, while promoted tumor suppressor p14, p16, p21 and p27 expression. In clinical specimens, SOCS2 was over-expressed in tumors and H. pylori positive tissues and its mRNA levels were inversely correlated with miR-101 expression. Taken together, our results indicated that miR-101 functions as a growth-suppressive miRNA in H. pylori related GC, and that its suppressive effects are mediated mainly by repressing SOCS2 expression.     

miR-623在膀胱癌中的表达及靶向Fascin1抑制膀胱癌细胞迁移和侵袭

目的:探讨miR-623在膀胱癌中的表达及通过靶向Fascin1对膀胱癌细胞迁移和侵袭能力的影响。方法:采用实时荧光定量PCR检测正常膀胱上皮组织、膀胱癌组织、正常永生化膀胱上皮细胞系(SV-HUC-1)和膀胱癌细胞系（T24、UMUC3）中miR-623的表达量;采用脂质体瞬时转染miR-623 mimics,划痕实验和Transwell侵袭实验检测miR-623过表达后膀胱癌细胞迁移、侵袭能力的改变;生物信息学预测miR-623的作用靶蛋白。miR-623过表达后Western blot及双荧光素酶报告基因检测其靶点的表达及结合情况;使用Fascin1特异性siRNA观察膀胱癌细胞迁移和侵袭能力的变化,并同时转染miR-623 inhibitor进行恢复实验。结果:miR-623在膀胱癌中的表达水平显著低于在正常膀胱组织中的表达（P＜0.05）,在膀胱癌细胞系（T24、UMUC3）中的表达水平显著低于正常膀胱细胞系(SV-HUC-1)（P＜0.05）;miR-623过表达显著抑制T24和UMUC3细胞的迁移和侵袭能力。生物信息学预测Fascin1为miR-623的靶基因,在T24和UMUC3细胞中过表达miR-623,能够显著降低Fascin1的蛋白水平;荧光素酶报告基因分析结果证实miR-623作用于Fascin1的3'-UTR。下调Fascin1表达能够抑制膀胱癌T24和UMUC3细胞的迁移和侵袭能力,同时抑制miR-623的表达能够提高细胞的迁移和侵袭能力。结论:miR-623在膀胱癌中表达水平降低,是一个抑癌因子;并可能通过靶向Fascin1调节膀胱癌的侵袭和转移能力。     

Methylation-associated silencing of MicroRNA-335 contributes tumor cell invasion and migration by interacting with RASA1 in gastric cancer

MicroRNAs (miRNAs) are small non-coding RNAs that function as endogenous silencers of target genes, previous studies have shown that miR-335 play an important role in suppressing metastasis and migration in human cancer including gastric cancer (GC). However, the mechanisms which result in aberrant expression of miR-335 in GC are still unknown. Recent studies have shown that the silencing of some miRNAs is associated with DNA hypermethylation. In this study, we find the promoter of miR-335 we embedded in CpG island by accessing to bioinformatics data and the low expression of miR-335 in 5 gastric cell lines can be restored by 5-aza-2’-deoxycytidine (5-Aza-dC) treatment. So we postulated that the miR-335 genes undergo epigenetic inactivation in GC. Subsequently, in GC cells and tissues, we performed quantitative real-time PCR (RTQ-PCR) to assess the expression of miR-335, and methylation-specific PCR (MSP) and bisulfite sequence-PCR (BSP) to evaluate the DNA methylation status in the CpG islands upstream of MiR-335. The result showed that the expression of miR-335 was significantly reduce in gastric cancer cell lines and tumor tissues compared to matched normal gastric tissues, and cell lines, and which is inverse correlation with DNA hypermethylation of miR-335 both in GC cells lines and tissues, but not in normal tissues. In addition, we found that the lower miR-335 expression induced by abnormal methylation may be mainly involved in gastric cell invasion and metastasis in GC tissues. No statistical significance was found about miR-335 expression and methylation level between healthy individuals with and without H. pylori (HP) infection. Finally, we carry out miRNA transfection, RTQ-PCR and western blot assay to find the RAS p21 protein activator (GTPase activating protein) 1 (RASA1) may be the possible target genes which lead to the gastric cell invasion and metastasis, furthermore, the re-expression of endogenous miR-335 by 5-Aza-dC treatment can exert effects similar to exogenous miRNAs transfection. Taken together, our results suggest that miR-335 may be silenced by promoter hypermethylation and play important roles in gastric cell invasion and metastasis through its target genes, such as RASA1. Its methylation level might be a predictive epigenetic marker of GC and remodeling on the expression by demethylation can provided a potential therapeutic strategy.     

miR-147a通过抑制CCND1和CDK4的表达对膀胱癌细胞周期和增殖的影响

目的:探讨miR-147a在膀胱癌组织、细胞中的表达及对膀胱癌细胞增殖和细胞周期的影响,研究miR-147a靶向负性调控CCND1和CDK4的表达对膀胱癌细胞周期和增殖的影响。方法:通过qRT-PCR检测miR-147a在正常膀胱组织和膀胱癌组织及正常膀胱上皮细胞、膀胱癌细胞系中的表达;使用miR-147a mimics转染观察细胞特性变化;CCK-8检测方法观察细胞增殖能力变化;流式细胞术观察细胞周期变化;生物信息学方法分析miR-147a的靶基因,并将靶基因进行GO分类和KEGG分析,找到与增殖和周期相关的基因;通过western blot方法验证miR-147a的靶基因,使用双萤光素酶报告基因系统检测miR-147a对CCND1和CDK4的转录活性影响;使用CCND1和CDK4特异性siRNA观察它们对细胞周期的影响,使用miR-147a inhibitor进行回补实验。结果:同正常组织/细胞相比,miR-147a在膀胱癌组织/膀胱癌细胞系中表达水平显著降低（P＜0.05）,miR-147a能够使膀胱癌细胞发生G1/S期阻滞,细胞增殖能力降低;通过一系列生信分析找到两个与细胞增殖和周期相关的miR-147a的靶基因CCND1和CDK4;通过间接和直接实验验证CCND1和CDK4是miR-147a的靶基因;下调CCND1和CDK4能够使膀胱癌细胞发生G1/S期阻滞,同时抑制miR-147a的表达能够解除G1/S期阻滞。结论:miR-147a作为一个抑癌因子,可作为诊断膀胱癌的生物标志物;miR-147a通过抑制CCND1和CDK4的表达抑制膀胱癌细胞周期G1/S期进程并抑制膀胱癌细胞增殖。     

miRNA-34a is associated with docetaxel resistance in human breast cancer cells

Docetaxel is a chemotherapy drug to treat breast cancer, however as with many chemotherapeutic drugs resistance to docetaxel occurs in 50% of patients, and the underlying molecular mechanisms of drug resistance are not fully understood. Gene regulation through microRNAs (miRNA) has been shown to play an important role in cancer drug resistance. By directly targeting mRNA, miRNAs are able to inhibit genes that are necessary for signalling pathways or drug induced apoptosis rendering cells drug resistant. This study investigated the role of differential miRNA expression in two in vitro breast cancer cell line models (MCF-7, MDA-MB-231) of acquired docetaxel resistance. MiRNA microarray analysis identified 299 and 226 miRNAs altered in MCF-7 and MDA-MB-231 docetaxel-resistant cells, respectively. Docetaxel resistance was associated with increased expression of miR-34a and miR-141 and decreased expression of miR-7, miR-16, miR-30a, miR-125a-5p, miR-126. Computational target prediction revealed eight candidate genes targeted by these miRNAs. Quantitative PCR and western analysis confirmed decreased expression of two genes, BCL-2 and CCND1, in docetaxel-resistant cells, which are both targeted by miR-34a. Modulation of miR-34a expression was correlated with BCL-2 and cyclin D1 protein expression changes and a direct interaction of miR-34a with BCL-2 was shown by luciferase assay. Inhibition of miR-34a enhanced response to docetaxel in MCF-7 docetaxel-resistant cells, whereas overexpression of miR-34a conferred resistance in MCF-7 docetaxel-sensitive cells. This study is the first to show differences in miRNA expression, in particular, increased expression of miR-34a in an acquired model of docetaxel resistance in breast cancer. This serves as a mechanism of acquired docetaxel resistance in these cells, possibly through direct interactions with BCL-2 and CCND1, therefore presenting a potential therapeutic target for the treatment of docetaxel-resistant breast cancer.