Overexpression Of miR-23a Research Articles

MiR-20b/106a modulate Ngn2 gene expression during neural differentiation of human umbilical cord mesenchymal stem cells.

The aim of this study was to perform neural differentiation of mesenchymal stem cells derived from Wharton's jelly of human umbilical cord (HUMSCs) and explore the role of miR-20b and miR-106a, which may regulate Neurogenin-2 (Ngn2) expression during the neural differentiation. HUMSCs were cultured and induced in vitro. The cells were stained for nestin and microtubule-associated protein 2 (MAP2) by immunofluorescence. The interactional binding sites between the 3'-untranslated region (3'-UTR) of Ngn2 mRNA and miR-20b or miR-106a were predicted by bioinformatics and identified by a dual-luciferase assay. The expressions of Ngn2, miR-20b, and miR-106a were determined by real-time PCR and western blot before and after the neural differentiation. After infection of miR-20b or miR-106a, the expressions of Ngn2, MAP2, and β III-tubulin (TUBB3) were measured. HUMSCs showed a uniform pattern with a typical short spindle-shaped morphology. Fourteen days after neural differentiation, HUMSCs showed neuronal traits of pyramidal appearance. TargetScan and miRanda showed that miR-20b and miR-106a were well complementary with Ngn2 3'-UTR. Identified by the dual-luciferase assay, we found that miR-20b and miR-106a inhibit Ngn2 expression by binding to its 3'-UTR. Furthermore, the expression of Ngn2 mRNA was almost reciprocal to that of miR-20b and miR-106a by real-time PCR during the neural differentiation of HUMSCs. Overexpression of miR-20b and miR-106a downregulated the expressions of Ngn2, MAP2, and TUBB3. miR-20b and miR-106a may directly or indirectly regulate neuronal genes expression to modulate the neural differentiation of HUMSCs.

MiR-19a protects cardiomyocytes from hypoxia/reoxygenation-induced apoptosis via PTEN/PI3K/p-Akt pathway.

miRNAs have been implicated in processing of cardiac hypoxia/reoxygenation (H/R)-induced injury. Recent studies demonstrated that miR-19a might provide a potential cardioprotective effect on myocardial disease. However, the effect of miR-19a in regulating myocardial ischemic injury has not been previously addressed. The present study was to investigate the effect of miR-19a on myocardial ischemic injury and identified the potential molecular mechanisms involved. Using the H/R model of rat cardiomyocytes H9C2 in vitro, we found that miR-19a was in low expression in H9C2 cells after H/R treatment and H/R dramatically decreased cardiomyocyte viability, and increased lactate dehydrogenase (LDH) release and cardiomyocyte apoptosis, which were attenuated by co-transfection with miR-19a mimic. Dual-luciferase reporter assay and Western blotting assay revealed that PTEN was a direct target gene of miR-19a, and miR-19a suppressed the expression of PTEN via binding to its 3′-UTR. We further identified that overexpression of miR-19a inhibited the expression of PTEN at the mRNA and protein levels. Moreover, PTEN was highly expressed in H/R H9C2 cells and the apoptosis induced by H/R was associated with the increase in PTEN expression. Importantly, miR-19a mimic significantly increased p-Akt levels under H/R. In conclusion, our findings indicate that miR-19a could protect against H/R-induced cardiomyocyte apoptosis by inhibiting PTEN /PI3K/p-Akt signaling pathway.

The mechanism of miR-23a in regulating myocardial cell apoptosis through targeting FoxO3.

Myocardial cell apoptosis represents important pathologic basis of ischemia-reperfusion injury (I/R). MiR-23a is related to myocardial hypertrophy and cardiac remodeling by regulating myocardial cell growth and apoptosis. This study intended to observe the regulating effect of miR-23a in myocardial cell and related target, and investigate its clinical significance to I/R injury. The rats were divided into sham group and myocardial I/R group. Myocardial cell cycle and miR-23a expression were tested. H2O2 was applied to treat H9c2 rat myocardial cell to simulate oxidative stress during I/R. The cells were divided into blank group, NC group, miR-23a mimic group, H2O2 group, and miR-23a + H2O2 group. ROS content and cell apoptosis were detected by flow cytometry. MiR-23a, FoxO3a, and BIM gene expression were determined by qRT-PCR. FoxO3a and BIM protein levels were measured by Western blot. Compared with sham group, myocardial apoptosis increased, while miR-23a expression was significantly downregulated in I/R group. H2O2 treatment markedly increased ROS levels in H9c2 cells and elevated apoptosis. The overexpression of mMiR-23a effectively reduced cell apoptosis induced by H2O2 treatment. H2O2 treatment significantly decreased miR-23a expression, while markedly elevated the levels of FoxO3a and BIM. The overexpression of miR-23a apparently impeded the induction of FoxO3a and BIM by H2O2. The downregulation of miR-23a plays a negative role in oxidative stress and cell apoptosis induced by I/R. The overexpression of miR-23a is of significance to alleviate cell apoptosis through inhibiting FoxO3a and downstream target BIM expression.

Overexpression of miR-19a inhibits colorectal cancer angiogenesis by suppressing KRAS expression

The microRNA miR-19a is closely related to tumor formation and development and is a key oncogene. Previous studies have demonstrated that miR-19a is upregulated in multiple cancer types, including colorectal cancer (CRC). However, most of these experiments were performed invitro, and consequently, the mechanisms underlying the effects of miR-19a on CRC are still unclear. Therefore, in the present study, we investigated the role of miR-19a in the development of solid CRC tumors. We generated KRAS 3'UTR-Mut by deleting the predicted binding site for miR-19a in KRAS, and observed that the expression of a reporter gene containing the KRAS 3'UTR in HCT116 cells was suppressed by miR-19a, while that of a reporter gene with mutant KRAS 3'UTR was unaffected by miR-19a. We observed that high miR-19a levels reduced KRAS expression. In the tube formation assay, overexpression of miR-19a exhibited anti-angiogenesis effects, which were rescued by KRAS expression. We established a nude mouse xenograft model to investigate the specific role of miR-19a in solid tumors. The results revealed that the sizes of xenograft tumors and density of blood vessels developed from HCT116 cells expressing miR-19a were smaller/lower compared with those of the control. KRAS and VEGFA levels were also reduced. In conclusion, our results revealed that miR-19a overexpression supressed KRAS expression and angiogenesis in CRC, indicating possibilities of using miR-19a in future therapeutic applications.

MiR-19a and miR-424 target TGFBR3 to promote epithelial-to-mesenchymal transition and migration of tongue squamous cell carcinoma cells

ABSTRACTPrevious studies indicate that TGFBR3 (transforming growth factor type III receptor, also known as betaglycan), a novel suppressor of progression in certain cancers, is down-regulated in tongue squamous cell carcinoma (TSCC). However, the role of this factor as an upstream regulator in TSCC cells remains to be elucidated. The present study was designed to elucidate whether TGFBR3 gene expression is regulated by two microRNA molecules, miR-19a and miR-424. The study also aimed to determine if these microRNAs promote migration of CAL-27 human oral squamous cells. Immunohistochemistry (IHC) and western blot analyses demonstrated that TGFBR3 protein levels were dramatically down-regulated in clinical TSCC specimens. Conversely, bioinformatics analyses and qRT-PCR results confirmed that both miR-19a and miR-424 were markedly up-regulated in clinical TSCC specimens. In this study, we observed that transfection of a TGFBR3-containing plasmid dramatically inhibited epithelial-to-mesenchymal transition (EMT) and migration in CAL-27 cells. Co-immunoprecipitation analyses also revealed that TGFBR3 forms a complex with the β-arrestin 2 scaffolding protein and IκBα. Furthermore, overexpression of TGFBR3 decreased p-p65 expression and increased IκBα expression; these effects were subsequently abolished following knockdown of β-arrestin 2. Moreover, over-expression of miR-19a and miR-424 promoted migration and EMT in CAL-27 cells. We also observed that the promotion of EMT by miR-19a and miR-424 was mediated by the inhibition of TGFBR3. Our study provides evidence that miR-19a and miR-424 play important roles in the development of TSCC. These results expand our understanding of TGFBR3 gene expression and regulatory mechanisms pertaining to miRNAs.

A miR-20a/MAPK1/c-Myc regulatory feedback loop regulates breast carcinogenesis and chemoresistance

Chemoresistance often leads to the failure of breast cancer treatment. MicroRNAs (miRNAs) play an important role in the progression and chemoresistance of cancer. However, because of the complexity of the mechanisms of chemoresistance and the specificity of miRNA regulation in different cell types, the function of miR-20a in breast cancer chemoresistance is still unclear. Here, by using miRNA microarray and high-content screening techniques, we found that miR-20a/b were significantly downregulated in breast cancer tissues compared with normal breast tissues, and low miR-20a/b expression was correlated with poor survival in breast cancer patients. Ectopic overexpression of miR-20a sensitized breast cancer cells to a broad spectrum of chemotherapy drugs and suppress their proliferation both in vitro and in vivo. Further study demonstrated that miR-20a directly targeted the 3'untranslated region of MAPK1, and thus downregulated the expression of P-gp and c-Myc by inhibiting the MAPK/ERK signaling pathway, whereas c-Myc can bind to the promoter region of the miR-20a gene to promote the expression of miR-20a. Together, our study identified a novel miR-20a/MAPK1/c-Myc feedback loop that regulates breast cancer growth and chemoresistance. These findings suggest that miR-20a synergizing with anticancer drugs will be a promising treatment strategy, especially for chemoresistant patients.

The Oncogenic Role of Tribbles 1 in Hepatocellular Carcinoma Is Mediated by a Feedback Loop Involving microRNA-23a and p53.

Hepatocellular carcinoma (HCC) is a common malignancy associated with a high risk of recurrence and metastasis and a poor prognosis. Here, we examined the involvement of the pseudokinase Tribbles 1 (TRIB1), a scaffold protein associated with several malignancies, in HCC and investigated the underlying mechanisms. TRIB1 was upregulated in HCC tissues and cell lines in correlation with low levels of p53. TRIB1 gain and loss of function experiments indicated that TRIB1 promoted HCC cell viability concomitant with the downregulation of p53, and induced HCC cell migration, invasion, and epithelial-mesenchymal transition. TRIB1 was identified as a target of microRNA-23a (miR-23a), and miR-23a overexpression downregulated TRIB1 and upregulated p53 in HCC cells. Ectopic expression of TRIB1 upregulated β-catenin and its effectors c-myc and MMP-7 in a p53-dependent manner. TRIB1 silencing inhibited tumor growth and promoted apoptosis in vivo via a mechanism that would involve the modulation of p53 and β-catenin signaling. The present results indicate that TRIB1 promotes HCC tumorigenesis and invasiveness via a feedback loop that involves the modulation of its expression by miR-23a with the likely downregulation of p53, and suggest the involvement of the β-catenin signaling pathway. These findings suggest potential targets for the treatment of HCC and therefore merit further investigation.

MicroRNA-20a promotes proliferation and invasion by directly targeting early growth response 2 in non-small cell lung carcinoma.

MicroRNA-20a (miR-20a) serves a notable role in tumor development and progression; it functions differently in different types of malignant tumor, and its role and mechanism in non-small cell lung carcinoma (NSCLC) remains unclear. In the present study, the effects of miR-20a on the proliferation and invasion of NSCLC cells and the underlying mechanisms behind this were investigated. Reverse transcription-quantitative polymerase chain reaction revealed that the expression level of miR-20a was higher in human NSCLC than in normal tissues. Following this, the effect of miR-20a on the proliferation, apoptosis, migration and invasion of NSCLCA-549 cells was further evaluated. In vitro analysis, including a Cell Counting Kit-8, colony formation and Transwell migration assay, indicated that miR-20a-knockdown inhibited the proliferation, invasion and migration, while promoting the cell apoptosis of the A-549 cells. Early growth response 2 (EGR2) protein and mRNA levels were downregulated or upregulated following the overexpression or knockdown of miR-20a, respectively. Dual-luciferase reporter gene assays implied that EGR2 is a direct target gene of miR-20a. The results of the present study indicated that miR-20a may function as an oncomiR in the development of NSCLC by promoting cell viability and motility. The inhibition of miR-20a could even become a novel therapeutic method for the treatment of NSCLC.

LncRNA XIST acts as a tumor suppressor in prostate cancer through sponging miR-23a to modulate RKIP expression.

Accumulating evidences have indicated that aberrant expression of long non-coding RNAs (LncRNAs) is tightly associated with cancer development. Previous studies have reported that lncRNA XIST regulates tumor malignancies in several cancers. However, the underlying mechanism of XIST in prostate cancer remains unclear. In the current study, we found that XIST was down-regulated in prostate cancer specimens and cell lines. Low expression of XIST was correlated with poor prognosis and advanced tumor stage in prostate cancer patients. In gain and loss of function assays, we confirmed that XIST suppressed cellular proliferation and metastasis in prostate cancer both in vitro and in vivo. Furthermore, we found that XIST negatively regulates the expression of miR-23a and subsequently promotes RKIP expression at post-transcriptional level. Consequently, we investigated the correlation between XIST and miR-23a, and identified miR-23a as a direct target of XIST. In addition, over-expression of miR-23a efficiently abrogated the up-regulation of RKIP induced by XIST, suggesting that XIST positively regulates the expression of RKIP by competitively binding to miR-23a. Taken together, our study indicated that lncRNA XIST acts as a tumor suppressor in prostate cancer, and this regulatory effect of XIST will shed new light on epigenetic diagnostics and therapeutics in prostate cancer.

Establishment of twist-1 and TGFBR2 as direct targets of microRNA-20a in mesenchymal to epithelial transition of breast cancer cell-line MDA-MB-231

Messenchymal to epithelial transition (MET) is a significant physiological phenomenon involved in embryogenesis and cancer. This study aims at investigating the mechanism of microRNA-20a (miR-20a) mediated regulation of mesenchymal to epithelial transition and identification of its direct target genes in breast cancer cell-line, MDA-MB-231. Reduced migratory and invasive property, altered cellular morphology along with reduced capability for attachment to basement membrane was acquired by over-expression of miR-20a in invasive MDA-MB-231 cell-line initially expressing low level of this micro-RNA, indicating direct correlation between abundance of miR-20a and metastatic property. The switch from mesenchymal to epithelial cells mediated by miR-20a involved post-transcriptional down-regulation of twist1, which in turn controls downstream epithelial markers like E-cadherin, claudin and mesenchymal markers like N-cadherin, fibronectin, the crucial players of mesenchymal to epithelial transition (MET). Furthermore, another key component, TGF-β and one of its receptors (TGFBR2) were found to be down-regulated by miR-20a. Additionally, reporter assay established that post-transcriptional down-regulation of TGFBR2 occurred through direct binding of miR-20a to its 3′UTR, thus abrogating the TGF-β signaling pathway resulting in inhibition of MET. Delineating the underlying molecular mechanism of miR-20a-mediated MET and defining the target genes will help us to introduce a miRNA-mediated effective therapeutic strategy against breast cancer.

MircroRNA-19a promotes vascular inflammation and foam cell formation by targeting HBP-1 in atherogenesis

Atherosclerosis, a serious threat to human cardiovascular health, involves inflammation throughout its various stages of development. MicroRNAs play an important regulatory role in macrophages that respond to inflammation, but the underlying mechanisms are largely unknown. In this work, we study the impact of miR-19a in macrophage-derived foam cell formation during atherogenesis. A microarray-based analysis of serums from patients with coronary heart disease in comparison with healthy controls reveals a significant enrichment of miR-19a in the serums of atherosclerosis patients. A higher level of miR-19a is also observed in atherosclerosis-prone ascending aortic wall tissues than in internal mammary artery amongst patients with coronary heart disease. We identify HMG-Box Transcription Factor 1 (HBP-1) as a target gene of miR-19a. HBP1 is repressor of macrophage migration inhibiting factor (MIF) and overexpression of miR-19a increases MIF expression. By administering a miR-19a antagonist to the caudal vein, we found a decrease in atherosclerotic plaques and lipids load in apoE-null mice fed with high-fat diet. These results support inhibition of miR-19a reduces inflammatory reaction and constitutes a potent therapeutic approach against atherosclerosis.

Oncogene miR-106a promotes proliferation and metastasis of prostate cancer cells by directly targeting PTEN in vivo and in vitro.

Prostate cancer (PCa) is the second leading contributor to male malignancy-associated death in developed countries. The study aimed to evaluate the effects of miR-106a on prostate cancer cells and the underlying molecular mechanism. The cell proliferation was detected using MTT assay and colony formation, and cells migration and invasion were also analyzed. Luciferase reporter assay was carried out to explore the correlation between miR-106a and PTEN. Besides, reverse transcriptase-polymerase chain reaction and western blot were carried out to measure the mRNA and protein levels in prostate tissues and PCa cells. Immunocytochemical staining was performed to detect the PTEN level in PCa tissues. MiR-106a level was dramatically increased in the PCa tissues and PCa cell lines. The overexpression of miR-106a significantly promoted the proliferation, migration and invasion of PCa cells. Besides, we confirmed that PTEN was regulated by miR-106a expression and was a direct target of miR-106a. Most importantly, we further found that miR-106a could promote the PCa cells xenograft growth in the nude mice by targeting PTEN, which was significantly downregulated in PCa tissues and cell lines and was closely related with PCa metastasis. MiR-106a as an oncogene could promote proliferation and metastasis of prostate cancer cells by directly targeting PTEN in vivo and in vitro.

MicroRNA-20a participates in the aerobic exercise-based prevention of coronary artery disease by targeting PTEN

BackgroundExercise can reduce the coronary artery disease (CAD) incidence. MiRNA-20a has been reported to distinctly expressed after sustain physical activity. However, its expression and regulation pattern in CAD model with or without exercise has not been reported. ObjectiveIn present study, we aim to investigate regulatory mechanism of miR-20a in exercise-associated reduced-CAD incidence and miR-20a-dependent signaling pathways. MethodsEight weeks old male ApoE/LDLR double knock out mice were recruited for this study. CAD model was established in mice fed with or without western diet and cholesterol levels were measured using detection kit as well as fast protein liquid chromatography. Relative mRNA levels were determined using quantitative RT-PCR while the protein levels were analyzed using western blotting. Luciferase assay was used to determine the miRNA binding site on target genes. CCK-8 assay and flow cytometry (FCM) were used for assessing the proliferative and apoptotic rate. ResultsOverall cholesterol level was significantly increased in CAD model group, compared to normal control group. Expression of miR-20 was significantly lower in CAD group where the VEGF and PTEN were upregulated, compared to non-CAD group. Increased miR-20a was induced after exercise in CAD model group, and miR-20a agomir group. Overexpression of miR-20a decreased the expression level of ET-1, TxA2, ANGII, PTEN and increased the eNOS, PGI2, and VEGF, at both transcriptional and translational levels. In vitro examination further confirmed these findings in human umbilical vein endothelial cells (HUVEC). MiR-20a specifically binds to the 3′UTR of PTEN and mediated the cell survival and proliferation through activating the PI3K/Akt signaling pathways. ConclusionMiRNA-20a may have great potential as therapeutic target for CAD, since its participation can induce alteration of functional genes as well as PTEN, which is specifically targeted by miR-20a, and promote the survival and proliferation of vein endothelial cells.

Lentivirus-mediated miR-23a overexpression induces trophoblast cell apoptosis through inhibiting X-linked inhibitor of apoptosis

Preeclampsia (PE) is a pregnancy-specific disorder representing a major cause of maternal and perinatal morbidity and mortality. MicroRNAs (miRNAs) have emerged as critical regulators in PE. However, the precise role of miRNAs in PE remains poorly understood. In this study, we aimed to investigate the potential role of miR-23a and the underlying mechanism in regulating trophoblast cell apoptosis. We found a significant increase of miR-23a expression in placental tissues from PE patients. Lentivirus-mediated miR-23a overexpression significantly induced apoptosis in trophoblast cells in vitro. X-linked inhibitor of apoptosis (XIAP) was identified as a target gene of miR-23a by bioinformatics analysis and dual-luciferase reporter assay. Overexpression of miR-23a significantly inhibited XIAP expression. Knockdown of XIAP also induced trophoblast cell apoptosis. Moreover, restoration of XIAP expression significantly abolished the miR-23 overexpression-induced trophoblast cell apoptosis. Taken together, our study demonstrates that miR-23a induces trophoblast cell apoptosis by inhibiting XIAP, which may contribute to PE. Our findings provide novel insights into understanding the pathogenesis of PE and suggest a potential therapeutic target in PE.

Long Noncoding RNA GAS5 Suppresses Tumorigenesis by Inhibiting miR-23a Expression in Non-Small Cell Lung Cancer.

Previous studies reported that elevated expression of long noncoding RNA (lncRNA) GAS5 led to the arrest of non-small cell lung cancer (NSCLC) cell growth and a promotion of apoptosis both in vitro and in vivo. However, its underlying molecular mechanism in NSCLC is still unclear. In the present study, we noted that GAS5 was downregulated in NSCLC tissues and cells and was negatively correlated with miR-23a expression. Luciferase reporter assay and qRT-PCR analysis demonstrated that GAS5 directly interacted with miR-23a and reversely regulated its expression. miR-23a overexpression markedly promoted NSCLC cell proliferation and invasion, while GAS5 overexpression dramatically inhibited NSCLC cell proliferation and invasion and promoted apoptosis. Functional analysis indicated that miR-23a overexpression significantly abolished GAS5 overexpression-induced inhibition of proliferation and invasion, as well as promotion of apoptosis in NSCLC cells. Moreover, xenograft experiments further revealed that upregulation of GAS5 notably impaired the growth of transplanted tumors by suppressing miR-23a in nude mice. These results suggested that overexpression of lncRNA GAS5 inhibits tumorigenesis of NSCLC by inhibiting miR-23a in vitro and in vivo, providing a potential therapeutic strategy for patients with NSCLC.

Abstract 477: Down-regulated miR-23a contributes to invasion and metastasis of cutaneous melanoma by promoting autophagy

Abstract Background: The occurrence of invasion and metastasis is the major cause of mortality in melanoma. Recent studies suggest that dysregulated miRNAs play critical roles in this procedure, but the underlying mechanism remains elusive. Here, we show that down-regulated miR-23a can promote invasion-metastasis cascade through autophagy in melanoma.Methods: The role of miR-23a in prognosis was assessed in a cohort of melanoma patients (n = 192) with Kaplan-Meier analysis. The effects of miR-23a overexpression were investigated using assays of invasion, migration and in a xenograft model (n = 10 mice per group). Autophagy-related target of miR-23a was confirmed by bioinformatics analysis, luciferase assays and immunoblotting. Molecular studies were performed to determine the downstream cellular and molecular mechanisms. All statistical tests were two-sided.Results: Serum miR-23a level was significantly down-regulated in melanoma patients (P< .001) and was highly correlated with poor clinical outcomes (P = .027, log-rank test). In addition, miR-23a level was remarkably decreased in metastatic melanoma tissues and cell lines (P<.05, P<.01). Moreover, miR-23a overexpression prevented the invasion and migration in vitro and lung and liver metastasis in vivo (both P< .05), by targeting ATG12 and inhibiting autophagy. Mechanically, miR-23a-ATG12 axis attenuated invasion and migration through autophagy-mediated AMPK-RhoA pathway. Finally, the down-regulation of miR-23a in metastatic melanoma was caused by RUNX2 in a transcriptional repression-manner. Conclusion: MiR-23a can act as a crucial epigenetic repressor of melanoma invasion and metastasis in an autophagy-dependent way, which indicates that miR-23a-mediated autophagy inhibition can be exploited to restrain invasion-metastasis cascade in melanoma treatment. Note: This abstract was not presented at the meeting. Citation Format: Weinan Guo, Huina Wang, Yuqi Yang, Sen Guo, Weigang Zhang, Tao Zhao, Lin Liu, Zhe Jian, Ling Liu, Gang Wang, Tianwen Gao, Qiong Shi, Chunying Li. Down-regulated miR-23a contributes to invasion and metastasis of cutaneous melanoma by promoting autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 477. doi:10.1158/1538-7445.AM2017-477

MiR-19a contributes to gefitinib resistance and epithelial mesenchymal transition in non-small cell lung cancer cells by targeting c-Met

Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is used as a first-line treatment for advanced non-small cell lung cancer (NSCLC). However, most NSCLC patients inevitably develop gefitinib resistance, and the mechanisms underlying this resistance are not fully understood. In this study, we show that miR-19a is significantly down-regulated in gefitinib-resistant NSCLC cell lines compared with gefitinib-sensitive cell lines. In addition, the down-regulation of miR-19a suppressed the expression of epithelial markers but induced the expression levels of mesenchymal markers. A mechanistic analysis revealed that miR-19a regulated c-Met expression by directly targeting the c-Met 3′UTR. Overexpression of miR-19a decreased c-Met expression and re-sensitized gefitinib-resistant NSCLC cells in vitro and in vivo. Consistent with the in vitro findings, the miR-19a serum level was significantly decreased in NSCLC patients with acquired gefitinib resistance compared with the level observed prior to the acquisition of resistance in each patient, indicating that miR-19a expression may be a valuable biomarker for the prediction of acquired gefitinib resistance in a clinical setting. Our data demonstrate that the miR-19a/c-Met pathway plays a critical role in acquired resistance to gefitinib and that the manipulation of miR-19a might provide a therapeutic strategy for overcoming acquired gefitinib resistance.

Biological effects and clinical characteristics of microRNA-106a in human colorectal cancer.

MicroRNAs serve important roles in various diseases, particularly cancer. microRNA-106a (miR-106a) exhibits abnormal expression and oncogenic activity in carcinogenesis. The clinical significance of the abnormal expression of miR-106a in colorectal cancer is poorly understood. In the present study, miR-106a expression from colorectal cancer tissues was quantified using the reverse transcription-quantitative polymerase chain reaction. The overexpression or knockdown of miR-106a was performed by transfection with microRNA mimic or inhibitor in human colorectal carcinoma HCT116 cells. The overexpression of miR-106a promoted viability and inhibited apoptosis in colorectal cancer cells. The association between miR-106a expression and clinicopathological factors was analyzed, and it was identified that miR-106a exhibited significantly increased expression in adenocarcinoma tissues compared with in mucinous carcinoma tissues, and the expression of miR-106a was identified to be associated with the depth of invasion and differentiation. The expression of miR-106a in plasma was also determined and it was identified that increased expression of miR-106a, as a characteristic of patients with colorectal cancer, may be distinguished from that of other patients by digitization of the areas under the receiver operating characteristic curves. These data suggested that miR-106a is a potential biomarker in the diagnosis of colorectal carcinoma. However, the underlying molecular mechanism of miR-106a-promoted viability and inhibition of apoptosis requires further investigation.

MicroRNA-23a and MicroRNA-27a Mimic Exercise by Ameliorating CKD-Induced Muscle Atrophy.

Muscle atrophy is a frequent complication of CKD, and exercise can attenuate the process. This study investigated the role of microRNA-23a (miR-23a) and miR-27a in the regulation of muscle mass in mice with CKD. These miRs are located in a gene cluster that is regulated by the transcription factor NFAT. CKD mice expressed less miR-23a in muscle than controls, and resistance exercise (muscle overload) increased the levels of miR-23a and miR-27a in CKD mice. Injection of an adeno-associated virus encoding the miR-23a/27a/24-2 precursor RNA into the tibialis anterior muscles of normal and CKD mice led to increases in mature miR-23a and miR-27a but not miR-24-2 in the muscles of both cohorts. Overexpression of miR-23a/miR-27a in CKD mice attenuated muscle loss, improved grip strength, increased the phosphorylation of Akt and FoxO1, and decreased the activation of phosphatase and tensin homolog (PTEN) and FoxO1 and the expression of TRIM63/MuRF1 and FBXO32/atrogin-1 proteins. Provision of miR-23a/miR-27a also reduced myostatin expression and downstream SMAD-2/3 signaling, decreased activation of caspase-3 and -7, and increased the expression of markers of muscle regeneration. Lastly, in silico miR target analysis and luciferase reporter assays in primary satellite cells identified PTEN and caspase-7 as targets of miR-23a and FoxO1 as a target of miR-27a in muscle. These findings provide new insights about the roles of the miR-23a/27a-24-2 cluster in CKD-induced muscle atrophy in mice and suggest a mechanism by which exercise helps to maintain muscle mass.

MiR-19 targeting of GSK3β mediates sulforaphane suppression of lung cancer stem cells

Cancer stem cells (CSCs) play a central role in the development of cancer. The canonical Wnt/β-catenin pathway is critical for maintaining stemness of CSCs. Phytochemicals from dietary compounds possess anti-CSCs properties and have been characterized as promising therapeutic agents for the prevention and treatment of many cancers. To date, the involvement and function of miR-19, a key oncogenic miRNA, in regulating Wnt/β-catenin pathway and lung CSCs has not been defined. Meanwhile, the effect of sulforaphane (SFN) on lung CSCs also remains to be elucidated. Here, we reported that lung CSCs up-regulated miR-19a and miR-19b expression. Overexpression of miR-19a/19b enhanced the ability of tumorsphere formation, up-regulated the expression of lung CSCs markers, increased Wnt/β-catenin pathway activation and β-catenin/TCF transcriptional activity in lung CSCs. In contrary, down-regulation of miR-19 suppressed lung CSCs activity and Wnt/β-catenin activation. We further revealed that miR-19 activated Wnt/β-catenin pathway by directly targeting GSK3β, the key negative modulator of this pathway. Moreover, we showed that SFN exhibited inhibitory effect on lung CSCs through suppressing miR-19 and Wnt/β-catenin pathway. Taken together, these data illustrate the role of miR-19 in regulating lung CSCs traits and miR-19/GSK3β/β-catenin axis in SFN intervention of lung CSCs. Findings from this study could provide important new insights into the molecular mechanisms of lung CSCs regulation as well as its target intervention.