The microRNA-217 functions as a tumor suppressor and is frequently downregulated in human osteosarcoma

ObjectiveDysregulation of miRNA is always associated with cancer development and progression. Aberrant expression of miR-217 has been found in some types of cancer. However, its expression and function in osteosarcoma remain unclear. The aim of this study was to explore the effects of miR-217 in osteosarcoma tumorigenesis and development.MethodsThe expression level of miR-217 was quantified by real-time RT-PCR in human osteosarcoma cell lines and tissues. MTT, flow cytometric, transwell invasion and migration assays, and tumorigenicity in vivo were adopted to observe the effects of miR-217 on MG-63 cell phenotypes.ResultsMiR-217 was significantly downregulated in osteosarcoma cell lines and clinical specimens. Decreased miR-217 expression was significantly associated with large tumor size, positive distant metastasis, and advanced clinical stage. Low miR-217 expression in osteosarcoma was an independent predictor of poor survival. Overexpression of miR-217 can inhibit the proliferation, invasion, migration and promoted apoptosis of MG-63 cells in vitro and in vivo.ConclusionsThese findings indicate that miR-217 may act as a tumor suppressor in osteosarcoma and would serve as a novel therapeutic agent for miRNA-based therapy.     

Retracted Article: SNHG3 promotes proliferation and invasion by regulating the miR-101/ZEB1 axis in breast cancer

Background: Dysregulated lncRNA expression contributes to the pathogenesis of human tumors via the lncRNAs functioning as oncogenes or tumor suppressors. Small nucleolar RNA host gene 3 (SNHG3) was demonstrated to be upregulated in breast cancer cells. However, the detailed roles and molecular mechanism of SNHG3 in breast cancer are largely unknown. Methods: The expression of SNHG3, miR-101, and zinc finger E-box-binding protein 1 (ZEB1) in breast cancer tissues and cells was detected using qRT-PCR. The effects of SNHG3 on cell proliferation and invasion were evaluated using MTT, EdU, and cell invasion assays. The protein levels of Ki-67, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase MMP-2, and MMP-9 were analyzed using western blot analysis. A luciferase reporter assay and RNA immunoprecipitation (RIP) were performed to explore the interaction between SNHG3, ZEB1 and miR-101. A subcellular fractionation assay was used to detect the subcellular location of SNHG3. Xenograft tumor experiments were conducted to verify the role and mechanism of SNHG3 in breast cancer in vivo. Results: SNHG3 expression was upregulated in breast cancer tissues and correlated with poor prognosis. SNHG3 knockdown suppressed breast cancer cell proliferation and invasion, which was further demonstrated by high levels of proliferation marker proteins Ki-67/PCNA and metastasis-related proteins MMP-2/MMP-9. Additionally, SNHG3 was located in the cytoplasm of breast cancer cells. SNHG3 functioned as a molecular sponge for miR-101 in breast cancer cells. miR-101 was downregulated in breast cancer tissues and negatively correlated with SNHG3 expression. Moreover, ZEB1, a target of miR-101, was positively regulated by SNHG3 in breast cancer cells. ZEB1 mRNA expression was upregulated in breast cancer tissues and positively correlated with SNHG3 expression. Mechanistically, SNHG3 knockdown suppressed cell proliferation and invasion by upregulation of miR-101 and downregulation of ZEB1 expression in breast cancer cells in vitro and in vivo. Conclusion: SNHG3 promoted proliferation and invasion by regulating the miR-101/ZEB1 axis in breast cancer.

In the present study, we investigated the expression and functional roles of SNHG3 in breast cancer cells, as well as the underlying mechanism of SNHG3 involved in the progression of breast cancer in vitro and in vivo.     

miR-135b reverses chemoresistance of non-small cell lung cancer cells by downregulation of FZD1

BackgroundNon-small cell lung cancer (NSCLC) chemoresistance usually limits the clinical efficacy of chemotherapeutic approaches. However, few reports have revealed the regulation of miR-135b and Frizzled-1 (FZD1) involved in NSCLC chemoresistance.MethodsTo identify the mechanism of miR-135b and FZD1 in NSCLC chemoresistance and to observe their biological functions, we detected the expression levels of miR-135b and FZD1 by conducting quantitative real-time polymerase chain reaction (RT-qPCR) and modified the expressions of miR-135b and FZD1 by transiently transfecting cells with miR-135b mimics or FZD1-siRNA. The 3′-untranslated region (3′-UTR) of FZD1 combined with miR-135b was verified through dual-luciferase reporter assay.ResultsCompared with that in A549 parental cell lines, the miR-135b expression in drug-resistant lung cancer cell lines (A549/DDP) was decreased and their FZD1 expression was increased. The increased miR-135b expression and silenced FZD1 expression enhanced the sensitivity of resistant cells to cisplatin treatment. The high expression of miR-135b in A549/DDP cells remarkably decreased the mRNA levels of FZD1. FZD1 was further identified as the functional downstream target of miR-135b by directly targeting the 3′-UTR of FZD1.ConclusionThe amplification of miR-135b suppressed NSCLC chemoresistance by directly mediating the FZD1 downregulation.     

Interference of lysine-specific demethylase 1 inhibits cellular invasion and proliferation in vivo in gastric cancer MKN-28 cells

BackgroundLysine-specific demethylase 1(LSD1), the first identified histone demethylase, plays an important role in the epigenetic regulation of gene activation and repression. Up-regulated LSD1expression has been reported in several malignant tumors.Our aim, therefore, was to better understand the mechanisms underlying the upregulation of LSD1 in gastric cancer.MethodsWe used lentiviral shRNA to knockdown LSD1 in the gastric cancer MKN-28 cell line. Cell proliferation was measured by MTT assay while cell apoptosis was assessed by Annexin V-FITC/PI double staining flow cytometry. The invasive potential of gastric cancer cells was determined by matrigel invasion assay. Protein expression was detected by Western blot. In vivo, the effect of knocking down LSD1 on tumor growth and protein expression in gastric cancer cells in nude mice was investigated.ResultsLSD1 knockdown in MKN-28 cell lines resulted in increasing the activity of cisplatin in vitro and the inhibition of cancer cell proliferation and invasion, and induced cell apoptosis. The expression of TGF-β1, VEGF, Bcl-2, β-catenin, p-ERK and p-Smad 2/3 proteins was inhibited in LSD1 knockdown cells. Moreover, in an in vivo model of gastric cancer, LSD1 knockdown suppressed tumor growth and protein expression.ConclusionLSD1 knockdown affected the fuction of gastric cancer MKN-28 cell line. LSD1 may be a latent target in the diagnosis and therapy of gastric cancer.     

miR-425 suppresses EMT and the development of TNBC (triple-negative breast cancer) by targeting the TGF-β 1/SMAD 3 signaling pathway

Background: EMT has a crucial effect on the progression and metastasis of tumors. This work will elucidate the role of miR-425 in EMT and the development of TNBC. Methods: The differential miRNA expression among non-tumor, para-tumor (adjacent tissue of tumor) and tumor tissues was analyzed. The luciferase activities of TGF-β1 3′UTR treated with miR-425 were determined. Then human breast cancer cell lines were treated with mimics or inhibitors of miR-425, and then the cell proliferation and migration, and invasion ability were assessed. The expression of TGF-β1 and markers of epithelial cells and mesenchymal cells were analyzed. The influences of miR-425 on the development of TNBC through inducing EMT by targeting the TGF-β1/SMAD3 signaling pathway in TNBC cell lines were investigated. Furthermore, xenograft mice were used to explore the potential roles of miR-425 on EMT and the development of TNBC in vivo. Results: Compared with non-tumor tissues, 9 miRNAs were upregulated and 3 miRNAs were down-regulated in tumor tissues. The relative expression of miR-425 in tumor tissues was obviously much lower than that in para-tumor and non-tumor tissues. MiR-425 suppressed TGF-β1 expression, and further inhibited expression of mesenchymal cell markers, while it exerted effects on cell proliferation and migration of TNBC cell lines. Moreover, the agomir of miR-425 could protect against the development process in a murine TNBC xenograft model. Conclusions: Our results demonstrated that miR-425 targets TGF-β1, and was a crucial suppressor on EMT and the development of TNBC through inhibiting the TGF-β1/SMAD3 signaling pathway. This suggests that aiming at the TGF-β1/SMAD3 signaling pathway by enhancing relative miR-425 expression, is a feasible therapy strategy for TNBC.

EMT has a crucial effect on the progression and metastasis of tumors.     

MicroRNA-132 cause apoptosis of glioma cells through blockade of the SREBP-1c metabolic pathway related to SIRT1

BackgroundThe inhibition role of miRNA (microRNA or miR) on cancer signaling pathways has been used to prospective cancer treatment. SIRT1 might promote tumorigenesis in human glioma.MethodsHere, we investigated whether miR-132 regulate the expression of SIRT1 and its downstream SREBP (Sterol regulatory element-binding protein)-lipogenesis-cholesterogenesis metabolic pathway in human glioma cells. Furthermore, we studied the effect on biology function of glioma cell induced by miR-132.ResultsMiR-132 inhibited SIRT1 and SREBP-1c expression and downregulated their targeted genes, including HMGCR and FASN. MiR-132 suppressed the cell growth, tumorigenicity, the invasion of glioma cells and migration as well as promoted their apoptosis. The pathways associated with cancer progression and tumorigenicity, and induce glioma cell apoptosis has been inhibited by miR-132 involving in a caspase-dependent apoptotic mechanism.ConclusionsThe recovery of miR-132 resulted in caspase-dependent apoptotic death in glioma cells. MiR-132 that was newly discovered represents a newly targeting mechanism in treatment for glioma.     

Puerarin induces platinum-resistant epithelial ovarian cancer cell apoptosis by targeting SIRT1

ObjectivePrevious investigations indicated the anticancer activity of puerarin. The current study aimed to evaluate the effect and molecular mechanisms of puerarin in chemotherapy-resistant ovarian cancer cells.MethodsWe examined the effects of puerarin in platinum-resistant epithelial ovarian cancer cells in vitro and in vivo. We also analyzed the molecular mechanism underlying Wnt/β-catenin inhibition and sirtuin 1 (SIRT1) regulation following puerarin treatment.ResultsOur study demonstrated that puerarin effectively inhibited cell growth in vitro and in vivo by increasing apoptosis in ovarian cancer cells. More importantly, puerarin sensitized cisplatin-resistant ovarian cancer cells to chemotherapy. Puerarin treatment decreased SIRT1 expression, which attenuated the nuclear accumulation of β-catenin to inhibit Wnt/β-catenin signaling. In addition, SIRT1 overexpression diminished the effects of puerarin treatment on cisplatin-resistant ovarian cancer cells. Further analysis supported SIRT1/β-catenin expression as a candidate biomarker for the disease progression of epithelial ovarian cancer.ConclusionsPuerarin increased the apoptosis of platinum-resistant ovarian cancer cells. The mechanism is partly related to the downregulation of SIRT1 and subsequent inhibition of Wnt/β-catenin signaling.     

The role of microRNA-572 in the proliferation and chemotherapeutic treatment of prostate cancer

ObjectiveMicroRNAs (miRNAs) regulate prostate tumorigenesis and progression by involving different molecular pathways. In this study, we examined the role of miR-572 in prostate cancer (PCa).MethodsThe proliferation rates of LNCaP and PC-3 PCa cells were studied using MTT assays. Transwell migration and Matrigel invasion assays were performed to evaluate cell migration and invasion, respectively. Protein expression levels were examined using western blotting. Docetaxel-induced apoptosis was evaluated by Caspase-Glo3/7 assays. The putative miR-572 binding site in the phosphatase and tensin homolog (PTEN) 3ʹ untranslated region (3ʹ UTR) was assessed with dual-luciferase reporter assays. Additionally, miR-572 expression levels in human PCa tissues were examined by qRT-PCR assays.ResultsUpregulation of miR-572 promoted proliferation, migration, and invasion of PCa cells. Overexpression of miR-572 decreased sensitivity of PCa cells to docetaxel treatment by reducing docetaxel-induced apoptosis. MiR-572 can regulate migration and invasion in PCa cells. Furthermore, miR-572 could regulate expression of PTEN and p-AKT in PCa cells by directly binding to the PTEN 3ʹ UTR. MiR-572 expression levels were increased in human PCa tissues and associated with PCa stage.ConclusionsmiR-572 displayed essential roles in PCa tumor growth and its expression level may be used to predict docetaxel treatment in these tumors.     

Decreased expression of microRNA-148a predicts poor prognosis in ovarian cancer and associates with tumor growth and metastasis

ObjectiveMicroRNA-148a (MiR-148a) had been reported to take part in some cancer progresses, but its clinical significance in ovarian cancer had been rarely reported. The purpose of this study was to evaluate the prognostic value of miR-148a as well as its roles in ovarian cancer progression.MethodsRelative expression of miR-148a in the plasma specimens of ovarian cancer patients was detected by qRT-PCR. Chi-square test was used to analyze the relationship between miR-148a expression and clinical characteristics. The overall survival was analyzed by Kaplan-Meier method and Cox regression analysis was used to evaluate the prognostic value of miR-148a. In addition, the ovarian cancer cell line SKOV-3 was separately transfected with pcDNA3-microRNA-148a over-expression vector and pcDNA3 empty vector to detect the functional roles of miR-148a in ovarian cancer progression.ResultsDecreased level of plasma miR-148a was observed in ovarian cancer patients compared with healthy controls. The expression level was associated with histopathologic grade, TNM stage and lymph node metastasis (P < 0.05 for all). Besides, patients with high level of miR-148a had a longer survival time than those with low level (40.3 months vs 31.6 months, log rank test, P = 0.002). Cox regression analysis indicated that miR-148a might be a potential biomarker for ovarian cancer prognosis (HR = 1.699, 95%CI = 1.175-2.456, P = 0.005). Moreover, cell experiments confirmed that miR-148a could inhibit proliferation, migration and invasion of ovarian cancer cells.ConclusionMiR-148a may be a potential prognostic factor for ovarian cancer and it can suppress tumor progression.     

Liraglutide suppresses obesity and promotes browning of white fat via miR-27b in vivo and in vitro

ObjectiveTo investigate the effect of liraglutide on the browning of white fat and the suppression of obesity via regulating microRNA (miR)-27b in vivo and in vitro.MethodsSprague-Dawley rats were fed a high-fat (HF) diet and 3T3-L1 pre-adipocytes were differentiated into mature white adipocytes. Rats and mature adipocytes were then treated with different doses of liraglutide. The mRNA and protein levels of browning-associated proteins, including uncoupling protein 1 (UCP1), PR domain containing 16 (PRDM16), CCAAT enhancer binding protein β (CEBPβ), cell death-inducing DFFA-like effector A (CIDEA) and peroxisome proliferator-activated receptor-γ-coactivator 1α (PGC-1α), were detected using quantitative real-time polymerase chain reaction and Western blotting.ResultsLiraglutide decreased body weight and reduced the levels of blood glucose, triglyceride and low-density lipoprotein cholesterol in HF diet-fed rats. Liraglutide increased the levels of UCP1, PRDM16, CEBPβ, CIDEA and PGC-1α in vivo and vitro. The levels of miR-27b were upregulated in HF diet-fed rats, whereas liraglutide reduced the levels of miR-27b. In vitro, overexpression of miR-27b decreased the mRNA and protein levels of UCP1, PRDM16, CEBPβ, CIDEA and PGC-1α. Transfection with the miR-27b mimics attenuated the effect of liraglutide on the browning of white adipocytes.ConclusionLiraglutide induced browning of white adipose through regulation of miR-27b.     

CXCL12/CXCR4轴通过诱导miR-125b促进肝癌细胞肿瘤干性和5-氟尿嘧啶抵抗的机制

目的探究趋化因子CXCL12/趋化因子受体CXCR4轴通过诱导miR-125b促进肝癌细胞肿瘤干性和5-氟尿嘧啶(5-FU)抵抗的机制。方法选择人肝细胞癌细胞系Huh7,分为7组:对照组(正常培养的肝细胞癌系),CXCR4转染组(CXCR4模拟转染超表达),CXCR4沉默组(CXCR4低表达或者不表达),miR-125b转染组(miR-125b超表达),CXCL12+125b抑制剂组(CXCL12超表达的+抑制miR-125b的表达),5-FU处理组(10μg/L的5-FU处理细胞),5-FU+miR-125b转染组(10μg/L的5-FU处理+miR-125b超表达的细胞)。聚合酶链式反应分析miR-125b mRNA表达;蛋白质印迹法检测E-钙粘蛋白、波形蛋白、CXCR4蛋白、Caspase-3、Bcl-2和Bax的蛋白表达;Transwell分析各组细胞中的细胞迁移、侵袭测定;MTT检测细胞存活力;细胞计数试剂盒8(CCK-8)评估细胞增殖。结果与对照组相比,CXCR4转染组miR-125b mRNA、波形蛋白、CXCR4的蛋白表达显著升高,E黏着蛋白表达显著降低(P<0.05);与CXCR4转染组相比,CXCR4沉默组miR-125b mRNA、波形蛋白、CXCR4的蛋白表达显著降低,E黏着蛋白表达显著升高(P<0.05)。与对照组相比,miR-125b转染组细胞迁移、侵袭数量、细胞活力均显著增加,细胞凋亡率显著降低(P<0.05);与miR-125b转染组相比,CXCL12+125b抑制剂组,细胞迁移、侵袭数量、细胞活均显著减少,细胞凋亡率显著升高(P<0.05)。与对照组相比,5-FU处理组细胞增殖率、Bcl-2表达显著降低,caspase-3、Bax的蛋白表达显著升高(P<0.05),与5-FU处理组相比,5-FU+miR-125b转染组细胞增殖率、Bcl-2表达显著升高,caspase-3、Bax的蛋白表达显著降低(P<0.05)。结论MiR-125b通过激活CXCL12/CXCR4轴而被上调,miR-125b增强CXCR4的表达,这在触发肿瘤侵袭和进展中形成了正反馈回路。这些结果为miR-125b在肝癌进程和化学抗性的发展中的作用提供了新的线索,为肝癌的治疗提供了潜在的治疗靶点。     

MiR-1 targets PIK3CA and inhibits tumorigenic properties of A549 cells

MicroRNAs are small endogenous RNAs that play important roles in the pathogenesis of human diseases, including malignancy. MicroRNA-1 (miR-1) is downregulated in non-small cell lung cancer (NSCLC); however, the underlying mechanisms by which it suppresses tumorigenesis in NSCLC are largely unknown. We investigated whether phosphoinositide-3-kinase catalytic subunit alpha (PIK3CA) was a novel target of miR-1 in the NSCLC cell line A549, and the mechanism of miR-1 inhibition of the tumorigenic properties of A549 cells is discussed. The influence of miR-1 on A549 cells was studied by transfection with miR-1 mimics or inhibitor. MiR-1 overexpression led to downregulation of PIK3CA protein, but not mRNA by western blot and quantitative real-time PCR, respectively. The dual-luciferase reporter assay confirmed that miR-1 targeted PIK3CA directly. PIK3CA downregulation by miR-1 mimics led to a significant reduction of phosphorylated Akt and survivin protein, the downstream targets of the PI3 K/Akt pathway. Cell proliferation was studied using a cell counting kit. Migration and invasion were evaluated by Transwell and Matrigel assays, respectively. Cell cycle and apoptosis were detected by flow cytometry. The results were that miR-1 upregulation inhibited A549 cell proliferation, migration, and invasion. These findings indicate that miR-1 may play an important role in the pathogenesis of NSCLC by regulating PIK3CA through the PI3 K/Akt pathway. Increasing miR-1 expression may provide a novel approach for NSCLC treatment.     

circVAPA promotes the proliferation,migration and invasion of oral cancer cells through the miR-132/HOXA7 axis

ObjectiveTo study the relationship between the circular RNA vesicle-associated membrane protein-associated protein A (circVAPA) and the pathogenesis of oral squamous cell carcinoma.MethodsThe expression of circVAPA was detected by RT-qPCR. In vitro loss-of-function experiments were performed in Cal-27 cells. The malignant phenotype of cells was evaluated by cell counting kit-8, clone formation and transwell assays. Luciferase reporter assays were used to assess the circVAPA/miR-132/homeobox A (HOXA) regulatory axis.ResultscircVAPA expression was significantly increased in oral cancer tissues and cells. The overall survival and progression-free survival of patients with oral cancer who exhibited high circVAPA expression were significantly shorter compared with those with low expression. circVAPA expression was closely related to tumor size, TNM stage and distant metastasis. circVAPA knockdown reduced the proliferation, invasion and migration of Cal-27 cells. MiR-132 was identified as a target of circVAPA in Cal-27 cells. Cotransfection with si-circVAPA and miR-132 inhibitor reversed the inhibitory effect of circVAPA knockdown on cell malignant phenotypes. HOXA7 was further identified as a downstream target of miR-132.ConclusioncircVAPA is highly expressed in oral cancer, and its abnormal expression might affect the proliferation, invasion and migration of oral cancer cells by modulating the miR-132/HOXA7 signaling axis.     

Prognostic value of miR-26a and HMGA1 in urothelial bladder cancer

BackgroundMicroRNA-26a (miR-26a) functions as a tumor suppressor by regulating its direct target gene high mobility group AT-hook 1 (HMGA1). This study was aimed to investigate the associations of differential expression of miR-26a and HMGA1 with tumor progression and prognosis in urothelial bladder cancer (UBC) patients.Materials and methodsOne hundred and twenty-six UBC patients were selected and quantitative real-time PCR was performed to detect the expression of miR-26a and HMGA1 mRNA in the respective tumors.ResultsOur data showed the decreased expression of miR-26a and the increased expression of HMGA1 mRNA in UBC tissues compared with corresponding non-cancerous tissues (both P < 0.001). Then, the expression levels of miR-26a in UBC tissues were negatively correlated with those of HMGA1 mRNA significantly (r = –0.72, P < 0.001). In addition, UBC patients with combined miR-26a downregulation and HMGA1 upregulation (miR-26a-low/HMGA1-high) more frequently had advanced pathological stage (P < 0.001) and high tumor grade (P < 0.001). Moreover, miR-26a-low/HMGA1-high expression was associated with a significantly shortest disease-free survival (P < 0.001) and overall survival (P < 0.001) of all miR-26a/HMGA1 combined expression groups. Furthermore, multivariate analysis indicated that miR-26a/HMGA1 expression was an independent prognostic factor for both disease-free survival and overall survival (both P = 0.001) in UBC patients.ConclusionInteraction between miR-26a and its target gene HMGA1 may contribute to the malignant progression of human UBC. Tumors with miR-26a downregulation in combination with high expression of HMGA1 showed a worse prognosis than the other tumors. Combined detection of their expression might be particularly helpful for surveillance of disease progression and treatment stratification.