MicroRNA-376c suppresses non-small-cell lung cancer cell growth and invasion by targeting LRH-1-mediated Wnt signaling pathway

MicroRNA-433-3p enhances chemosensitivity of glioma to cisplatin by downregulating NR5A2

OBJECTIVE

We attempted to investigate influence of microRNA-433-3p on malignant progression of glioma and identify its molecular mechanism, thus laying groundwork for glioma management.

METHODS

Expression data along with clinical data of glioma were accessed from the TCGA database for differential and survival analyses to look for the target differentially expressed genes. Quantitative reverse transcriptase PCR (qRT-PCR) and western blot were utilized to assess NR5A2 mRNA and protein expression in different glioma cell lines, respectively. MTT, Transwell assay, and flow cytometry were carried out to assay the impact of NR5A2 on behaviors of glioma cells in vitro. Bioinformatics analysis was used to identify the upstream microRNA of NR5A2 in glioma, while dual-luciferase and western blot assays were used to detect binding of microRNA and NR5A2. Chemosensitivity of glioma cells was evaluated by cisplatin cytotoxicity test.

RESULTS

NR5A2 was upregulated in both glioma tissues and cell lines. Dual-luciferase assay result showed binding site of microRNA-433-3p on NR5A2 mRNA 3'UTR, and microRNA-433-3p reduced NR5A2 expression. Cell assays revealed that silencing NR5A2 could hamper proliferation, invasion, and migration and enhance chemosensitivity to cisplatin while promoting glioma cell apoptosis and blocking glioma cells in G0/G1 phase. Rescue experiments also indicated that microRNA-433-3p suppressed glioma malignant progression via inhibiting NR5A2.

CONCLUSION

MicroRNA-433-3p which is significantly poorly expressed in glioma targets NR5A2 to suppress glioma malignant progression and enhance chemosensitivity to cisplatin.

APE1 controls DICER1 expression in NSCLC through miR-33a and miR-130b

Increasing evidence suggests different, not completely understood roles of microRNA biogenesis in the development and progression of lung cancer. The overexpression of the DNA repair protein apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) is an important cause of poor chemotherapeutic response in lung cancer and its involvement in onco-miRNAs biogenesis has been recently described. Whether APE1 regulates miRNAs acting as prognostic biomarkers of lung cancer has not been investigated, yet. In this study, we analyzed miRNAs differential expression upon APE1 depletion in the A549 lung cancer cell line using high-throughput methods. We defined a signature of 13 miRNAs that strongly correlate with APE1 expression in human lung cancer: miR-1246, miR-4488, miR-24, miR-183, miR-660, miR-130b, miR-543, miR-200c, miR-376c, miR-218, miR-146a, miR-92b and miR-33a. Functional enrichment analysis of this signature revealed its biological relevance in cancer cell proliferation and survival. We validated DICER1 as a direct functional target of the APE1-regulated miRNA-33a-5p and miR-130b-3p. Importantly, IHC analyses of different human tumors confirmed a negative correlation existing between APE1 and Dicer1 protein levels. DICER1 downregulation represents a prognostic marker of cancer development but the mechanisms at the basis of this phenomenon are still completely unknown. Our findings, suggesting that APE1 modulates DICER1 expression via miR-33a and miR-130b, reveal new mechanistic insights on DICER1 regulation, which are of relevance in lung cancer chemoresistance and cancer invasiveness.

Targeting Nuclear Receptors in Lung Cancer—Novel Therapeutic Prospects

Lung cancer, the second most commonly diagnosed cancer, is the major cause of fatalities worldwide for both men and women, with an estimated 2.2 million new incidences and 1.8 million deaths, according to GLOBOCAN 2020. Although various risk factors for lung cancer pathogenesis have been reported, controlling smoking alone has a significant value as a preventive measure. In spite of decades of extensive research, mechanistic cues and targets need to be profoundly explored to develop potential diagnostics, treatments, and reliable therapies for this disease. Nuclear receptors (NRs) function as transcription factors that control diverse biological processes such as cell growth, differentiation, development, and metabolism. The aberrant expression of NRs has been involved in a variety of disorders, including cancer. Deregulation of distinct NRs in lung cancer has been associated with numerous events, including mutations, epigenetic modifications, and different signaling cascades. Substantial efforts have been made to develop several small molecules as agonists or antagonists directed to target specific NRs for inhibiting tumor cell growth, migration, and invasion and inducing apoptosis in lung cancer, which makes NRs promising candidates for reliable lung cancer therapeutics. The current work focuses on the importance of various NRs in the development and progression of lung cancer and highlights the different small molecules (e.g., agonist or antagonist) that influence NR expression, with the goal of establishing them as viable therapeutics to combat lung cancer.

The Important Role of N6-methyladenosine RNA Modification in Non-Small Cell Lung Cancer

N6-methyladenosine (m⁶A) is one of the most prevalent epigenetic modifications of eukaryotic RNA. The m⁶A modification is a dynamic and reversible process, regulated by three kinds of regulator, including m⁶A methyltransferases, demethylases and m⁶A-binding proteins, and this modification plays a vital role in many diseases, especially in cancers. Accumulated evidence has proven that this modification has a significant effect on cellular biological functions and cancer progression; however, little is known about the effects of the m⁶A modification in non-small cell lung cancer (NSCLC). In this review, we summarized how various m⁶A regulators modulate m⁶A RNA metabolism and demonstrated the effect of m⁶A modification on the progression and cellular biological functions of NSCLC. We also discussed how m⁶A modification affects the treatment, drug resistance, diagnosis and prognosis of NSCLC patients.

Systematic review and meta-analysis of the prognostic significance of microRNAs related to metastatic and EMT process among prostate cancer patients

The ability of tumor cells to spread from their origin place and form secondary tumor foci is determined by the epithelial-mesenchymal transition process. In epithelial tumors such as prostate cancer (PCa), the loss of intercellular interactions can be observed as a change in expression of polarity proteins. Epithelial cells acquire ability to migrate, what leads to the formation of distal metastases. In recent years, the interest in miRNA molecules as potential future treatment options has increased. In tumor microenvironment, miRNAs have the ability to regulate signal transduction pathways, where they can act as suppressors or oncogenes. MiRNAs are secreted by cancer cells, and the changes in their expression levels are closely related to a cancer progression, including epithelial-mesenchymal transition. These molecules offer new diagnostic and therapeutic possibilities. Therapeutics which make use of synthesized RNA fragments and mimic or block miRNAs affected in PCa, may lead to inhibition of tumor progression and even disease re-emission. Based on appropriate qualification criteria, we conducted a selection process to identify scientific articles describing miRNAs and their relation to epithelial-mesenchymal transition in PCa patients. The studies were published in English on Pubmed, Scopus and the Web of Science before August 08, 2019. Hazard ratios (HRs) and 95% confidence intervals (CI) as well as total Gleason score were used to assess the concordance between miRNAs and presence of metastases. A total of 13 studies were included in our meta-analysis, representing 1608 PCa patients and 15 miRNA molecules. Our study clarifies a relationship between the clinicopathological features of PCa and the aberrant expression of several miRNA as well as the complex mechanism of miRNA molecules involvement in the induction and promotion of the metastatic mechanism in PCa.

Loading MicroRNA-376c in Extracellular Vesicles Inhibits Properties of Non-Small Cell Lung Cancer Cells by Targeting YTHDF1

Objective:

Extracellular vesicles (Evs) secreted from cells have been revealed to mediate signal transduction between cells. Nevertheless, the mechanisms through which molecules transported by EVs function remain to be elucidated. In the present study, the functional relevance of endothelial cells (ECs)-secreted Evs carrying microRNA-376c (miR-376c) in the biological activities of non-small cell lung cancer (NSCLC) cells was investigated, including the related mechanisms.

Methods:

Two cell lines with the highest YTH N6-methyladenosine (m6A) RNA binding protein 1 (YTHDF1) expression were selected for subsequent experiments. Cellular proliferation, migration, invasion and apoptosis were measured by EdU, wound healing, Transwell assays and flow cytometry, respectively. The binding relationship between miR-376c and YTHDF1 was analyzed by dual-luciferase reporter assays. The miR-376c, YTHDF1 and β-catenin expression was evaluated by qPCR assays and western blot assays.

Results:

The expression patterns of YTHDF1 were higher in NSCLC cells, whereas miR-376c was reduced versus the normal bronchial epithelial cells. Silencing of YTHDF1 repressed NSCLC cell proliferation, invasion and migration abilities, whereas enhanced apoptosis. miR-376c negatively modulated YTHDF1 expression. Under co-culture conditions, ECs transmitted miR-376c into NSCLC cells through Evs, and inhibited the intracellular YTHDF1 expression and the Wnt/β-catenin pathway activation. Rescue experiments revealed that YTHDF1 overexpression reversed the inhibitory role of miR-376c released by EC-Evs in NSCLC cells.

Conclusion:

EC-delivered Evs inhibit YTHDF1 expression and the Wnt/β-catenin pathway induction via miR-376c overexpression, thus inhibiting the malignant phenotypes of NSCLC cells.

Validation of Altered Umbilical Cord Blood MicroRNA Expression in Neonatal Hypoxic-Ischemic Encephalopathy

Importance

Neonatal hypoxic-ischemic encephalopathy (HIE) remains a significant cause of neurologic disability. Identifying infants suitable for therapeutic hypothermia (TH) within a narrow therapeutic time is difficult. No single robust biochemical marker is available to clinicians.

Objective

To assess the ability of a panel of candidate microRNA (miRNA) to evaluate the development and severity of encephalopathy following perinatal asphyxia (PA).

Design, Setting, and Participants

This validation study included 2 cohorts. For the discovery cohort, full-term infants with PA were enrolled at birth to the Biomarkers in Hypoxic-Ischemic Encephalopathy (BiHiVE1) study (2009-2011) in Cork, Ireland. Encephalopathy grade was defined using early electroencephalogram and Sarnat score (n = 68). The BiHiVE1 cohort also enrolled healthy control infants (n = 22). For the validation cohort, the BiHiVE2 multicenter study (2013-2015), based in Cork, Ireland (7500 live births per annum), and Karolinska Huddinge, Sweden (4400 live births per annum), recruited infants with PA along with healthy control infants to validate findings from BiHiVE1 using identical recruitment criteria (n = 80). The experimental design was formulated prior to recruitment, and analysis was conducted from June 2016 to March 2017.

Main Outcomes and Measures

Alterations in umbilical cord whole-blood miRNA expression.

Results

From 170 neonates, 160 were included in the final analysis. The BiHiVE1 cohort included 87 infants (21 control infants, 39 infants with PA, and 27 infants with HIE), and BiHiVE2 included 73 infants (control [n = 22], PA [n = 26], and HIE [n = 25]). The BiHiVE1 and BiHiVE2 had a median age of 40 weeks (interquartile range [IQR], 39-41 weeks) and 40 weeks (IQR, 39-41 weeks), respectively, and included 56 boys and 31 girls and 45 boys and 28 girls, respectively. In BiHiVE1, 12 candidate miRNAs were identified, and 7 of these miRNAs were chosen for validation in BiHiVE2. The BiHiVE2 cohort showed consistent alteration of 3 miRNAs; miR-374a-5p was decreased in infants diagnosed as having HIE compared with healthy control infants (median relative quantification, 0.38; IQR, 0.17-0.77 vs 0.95; IQR, 0.68-1.19; P = .009), miR-376c-3p was decreased in infants with PA compared with healthy control infants (median, 0.42; IQR, 0.21-0.61 vs 0.90; IQR, 0.70-1.30; P = .004), and mir-181b-5p was decreased in infants eligible for TH (median, 0.27; IQR, 0.14-1.41) vs 1.18; IQR, 0.70-2.05; P = .02).

Conclusions and Relevance

Altered miRNA expression was detected in umbilical cord blood of neonates with PA and HIE. These miRNA could assist diagnostic markers for early detection of HIE and PA at birth.

A network embedding-based multiple information integration method for the MiRNA-disease association prediction

BACKGROUND

MiRNAs play significant roles in many fundamental and important biological processes, and predicting potential miRNA-disease associations makes contributions to understanding the molecular mechanism of human diseases. Existing state-of-the-art methods make use of miRNA-target associations, miRNA-family associations, miRNA functional similarity, disease semantic similarity and known miRNA-disease associations, but the known miRNA-disease associations are not well exploited.

RESULTS

In this paper, a network embedding-based multiple information integration method (NEMII) is proposed for the miRNA-disease association prediction. First, known miRNA-disease associations are formulated as a bipartite network, and the network embedding method Structural Deep Network Embedding (SDNE) is adopted to learn embeddings of nodes in the bipartite network. Second, the embedding representations of miRNAs and diseases are combined with biological features about miRNAs and diseases (miRNA-family associations and disease semantic similarities) to represent miRNA-disease pairs. Third, the prediction models are constructed based on the miRNA-disease pairs by using the random forest. In computational experiments, NEMII achieves high-accuracy performances and outperforms other state-of-the-art methods: GRNMF, NTSMDA and PBMDA. The usefulness of NEMII is further validated by case studies. The studies demonstrate the great potential of network embedding method for the miRNA-disease association prediction, and SDNE outperforms other popular network embedding methods: DeepWalk, High-Order Proximity preserved Embedding (HOPE) and Laplacian Eigenmaps (LE).

CONCLUSION

We propose a new method, named NEMII, for predicting miRNA-disease associations, which has great potential to benefit the field of miRNA-disease association prediction.

Negative regulators of Wnt signaling in non-small cell lung cancer: Theoretical basis and therapeutic potency

Significant advances in the treatment of non-small cell lung cancer (NSCLC) have been made over the past decade, and they predominantly involve molecular targets such as epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements. However, despite the initial good response, drug resistance eventually develops. The Wnt signaling pathway has recently been considered important in embryonic development and tumorigenesis in many cancers, particularly NSCLC. Moreover, the aberrant Wnt pathway plays a significant role in NSCLC and is associated with cancer cell proliferation, metastasis, invasion and drug resistance, and the suppression of canonical or noncanonical Wnt signaling through various biological or pharmacological negative regulators has been proven to produce specific anticancer effects. Thus, blocking the Wnt pathway via its negative regulators may overcome the resistance of current treatment methods and lead to new treatment strategies for NSCLC. Therefore, in this review, we summarize recent studies on the role of negative regulators in Wnt signaling in NSCLC and the therapeutic potency of these molecules as agents and targets for NSCLC treatments.

Nr5a2 promotes cancer stem cell properties and tumorigenesis in nonsmall cell lung cancer by regulating Nanog

Lung cancer has the highest mortality rate due to late diagnosis and high incidence of metastasis. Cancer stem cells (CSCs) are a subgroup of cancer cells with self‐renewal capability similar to that of normal stem cells (NSCs). While CSCs may play an important role in cancer progression, mechanisms underlying CSC self‐renewal and the relationship between self‐renewal of the NSCs and CSCs remain elusive. The orphan nuclear receptor Nr5a2 is a transcriptional factor, and a regulator of stemness of embryonic stem cells and induced pluripotent stem cells. However, whether Nr5a2 regulates the self‐renewal of lung CSCs is unknown. Here, we showed the diagnostic and prognostic values of elevated Nr5a2 expression in human lung cancer. We generated the mouse LLC‐SD lung carcinoma CSC cellular model in which Nr5a2 expression was enhanced. Using the LLC‐SD model, through transient and stable siRNA interference of Nr5a2 expression, we provided convincing evidence for a regulatory role of Nr5a2 in the maintenance of lung CSC self‐renewal and stem cell properties in vitro. Further, using the syngeneic and orthotopic lung transplantation model, we elucidated augmented cancer biological properties associated with Nr5a2 promotion of LLC‐SD self‐renewal. More importantly, we revealed that Nr5a2’s regulatory role in promoting LLC‐SD self‐renewal is mediated by transcriptional activation of its direct target Nanog. Taken together, in this study, we have provided convincing evidence in vitro and in vivo demonstrating that Nr5a2 can induce lung CSC properties and promote tumorigenesis and progression through transcriptional up‐regulation of Nanog.

MicroRNA‑409 may function as a tumor suppressor in endometrial carcinoma cells by targeting Smad2

MicroRNAs (miRNAs) are frequently dysregulated in human cancer and can act as either potent oncogenes or tumor suppressor genes. The aberrant expression of miRNA‑409 (miR‑409) has been found in certain types of cancer, however, its expression and potential biological role in endometrial cancer remain to be fully elucidated. In the present study, a total of 16 pairs of tissue samples from 16 patients with endometrial cancer were used in the present study, each of which consisted of human endometrial cancer tissue and matched adjacent normal tissue from the same patient. The expression of miR‑409 of the tissue were detected and its associations with Ishikawa and HEC‑1B human endometrial cancer cell lines were studied. The results of the present study demonstrated that miR‑409 was downregulated in human endometrial cancer, and it suppressed the growth of Ishikawa and HEC‑1B human endometrial cancer cell lines. Bioinformatics analysis indicated that small mothers against decapentaplegic 2 (Smad2) was a putative target of miR‑409. In a luciferase reporter system, it was confirmed that Smad2 was a direct target gene of miR‑409. It was also demonstrated that Smad2 was upregulated in human endometrial cancer tissues, and this was inversely correlated with the expression of miR‑409. These findings indicated that miR‑409 targeted the Smad2 transcript and suppressed endometrial cancer cell growth, suggesting that miR‑409 has a tumor suppressive role in the pathogenesis of human endometrial cancer.

Hsa-miR-376c-3p targets Cyclin D1 and induces G1-cell cycle arrest in neuroblastoma cells

High-risk neuroblastoma is the most aggressive form of cancer in children. The estimated survival of children with high-risk neuroblastoma is 40-50% compared with low and intermediate risk neuroblastoma, which is >98 and 90-95%, respectively. In addition, patients with high-risk neuroblastoma often experience relapse following intensive treatments with standard chemotherapeutic drugs. Therefore alternative strategies are required to address this problem. MicroRNAs (miRNAs/miRs) are small, endogenously expressed non-coding RNAs, which when deregulated have been demonstrated to serve significant roles in the tumorigenesis of a number of different types of cancer. Results from a previous deep sequencing study identified 22 downregulated miRNAs from the 14q32 miRNA cluster differentially expressed in neuroblastoma cell lines isolated from 6 patients at diagnosis and at relapse following intensive treatments. miR-376c-3p is one of the 22 miRNAs that was downregulated in the majority of the cell lines isolated from patients post treatment. The present study employed reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to quantify the basic expression of miR-376c-3p in 6 neuroblastoma cell lines. The functional role of miR-376c-3p in the neuroblastoma cell lines was evaluated by alamar blue-cell viability and propidium iodide-flow cytometric assays. In addition, luciferase reporter assays, RT-qPCR and western blotting were performed to identify and quantify the targets of miR-376c-3p in neuroblastoma cell lines. Ectopic expression of miR-376c-3p led to significant inhibition of cell viability and G1-cell cycle arrest in multiple neuroblastoma cell lines by reducing the expression of cyclin D1, an oncogene critical for neuroblastoma pathogenesis. The results of the present study provide novel insights into the functional role of miR-376c-3p and suggest new approaches for the treatment of neuroblastoma.

MicroRNA-374b reduces the proliferation and invasion of colon cancer cells by regulation of LRH-1/Wnt signaling

Deregulation of microRNA (miRNA) has been suggested as a critical event in colon cancer development and progression. Recent studies have suggested that miR-374b is a novel cancer-related miRNA involved in several cancer types. Thus far, very little is known about the role of miR-374b in colon cancer; therefore, the goal of this study was to investigate the potential role of miR-374b in colon cancer. Here, we showed that miR-374b expression was significantly downregulated in colon cancer tissues and cell lines. Overexpression of miR-374b inhibited the proliferation and invasion of colon cancer cells, while miR-374b suppression promoted colon cancer cell proliferation and invasion. Liver receptor homolog-1 (LRH-1) was identified as a target of miR-374b in colon cancer cells. Both the mRNA and protein expression of LRH-1 were regulated by miR-374b. In addition, an inverse correlation between LRH-1 mRNA and miR-374b expression was evidenced in colon cancer specimens. Notably, overexpression of miR-374b also downregulated the Wnt signaling in colon cancer cells. Furthermore, restoration of LRH-1 expression significantly abolished the antitumor effect of miR-374b in colon cancer cells. These findings suggest that miR-374b inhibits colon cancer cell proliferation and invasion through downregulation of LRH-1 expression. Inhibiting LRH-1 by miR-374b may represent a novel therapeutic strategy for the treatment of colon cancer.

MicroRNA-381 serves as a prognostic factor and inhibits migration and invasion in non-small cell lung cancer by targeting LRH-1

Accumulating evidence has demonstrated that aberrant miRNAs were involved in carcinogenesis and tumor progression by regulating oncogenes or tumor suppressor expression. Dysregulation of miR-381 has been reported in different tumors. However, the clinical roles and underlying mechanism in non-small cell lung cancer (NSCLC) remains to be elucidated. We found the expression of miR-381 was significantly downregulated in both NSCLC tissues and cell lines. Clinical analysis revealed the reduced miR-381 was obviously associated with advanced TNM stage and lymph node metastasis. Moreover, we disclosed that miR-381 was a novel independent prognostic marker for predicting 5-year survival of NSCLC patients. The ectopic overexpression of miR-381 inhibited cell migration and invasion in vitro and in vivo. Notably, miR-381 could modulate LRH-1 by directly binding to its 3'-UTR. In clinical samples of NSCLC, miR-381 inversely correlated with LRH-1 expression, which performed positive roles in NSCLC migration and invasion. Alteration of LRH-1 expression at least partially abolished the migration and invasion of miR-381 on NSCLC cells. Here, we identified LRH-1 as a functional target of miR-381 in NSCLC. In conclusion, our data indicated that miR-381 inhibited migration and invasion of NSCLC by targeting LRH-1, and may represent a novel potential therapeutic target and prognostic marker for NSCLC.

The crosstalk between microRNAs and the Wnt/β-catenin signaling pathway in cancer

Mounting evidence has indicated microRNA (miR) dysregulation and the Wnt/β-catenin signaling pathway jointly drive carcinogenesis, cancer metastasis, and drug-resistance. The current review will focus on the role of the crosstalk between miRs and the Wnt/β-catenin signaling pathway in cancer development. MiRs were found to activate or inhibit the canonical Wnt pathway at various steps. On the other hand, Wnt activation increases expression of miR by directly binding to its promoter and activating transcription. Moreover, there are mutual feedback loops between some miRs and the Wnt/β-catenin signaling pathway. Clinical trials of miR-based therapeutic agents are investigated for solid and hematological tumors, however, challenges concerning low bioavailability and possible side effects must be overcome before the final clinical application. This review will describe current understanding of miR crosstalk with the Wnt/β-catenin signaling cascade. Better understanding of the regulatory network will provide insight into miR-based therapeutic development.

WNT signaling - lung cancer is no exception

Since the initial discovery of the oncogenic activity of WNT ligands our understanding of the complex roles for WNT signaling pathways in lung cancers has increased substantially. In the current review, the various effects of activation and inhibition of the WNT signaling pathways are summarized in the context of lung carcinogenesis. Recent evidence regarding WNT ligand transport mechanisms, the role of WNT signaling in lung cancer angiogenesis and drug transporter regulation and the importance of microRNA and posttranscriptional regulation of WNT signaling are also reviewed.

MicroRNA-136 inhibits colon cancer cell proliferation and invasion through targeting liver receptor homolog-1/Wnt signaling

An increasing number of studies have reported that microRNAs (miRNAs) are involved in the malignant behavior of colon cancer cells through directly targeting multiple tumor suppressors or oncogenes. The expression and role of miR-136 has been reported in several types of human cancer. However, the role of miR-136 in colon cancer remains unclear. In this study, we aimed to investigate the expression and function of miR-136 in colon cancer and the potential underlying mechanism. Here, we found that miR-136 was decreased in colon cancer cell lines and tissues. Overexpression of miR-136 inhibited the proliferation and invasion in SW480 and HCT116 cell lines while suppression of miR-136 exhibited the opposite effect. Liver receptor homolog-1 (LRH-1) was identified as a direct target gene of miR-136. Notably, miR-136 overexpression suppressed LRH-1 expression as well as Wnt signaling in SW480 and HCT116 cell lines. The miR-136 expression level inversely correlated with LRH-1 mRNA expression in colon cancer specimens. Moreover, overexpression of LRH-1 partially reversed the miR-136-induced antitumor effect in SW480 and HCT116 cell lines. Taken together, these findings suggest that miR-136 functions as a negative regulator in colon cancer progression by targeting LRH-1 and that miR-136 downregulation contributes to high expression of LRH-1 and aberrant activation of Wnt signaling, leaving open the possibility that miR-136 may serve as a potential therapeutic target for colon cancer.

MiR-557 works as a tumor suppressor in human lung cancers by negatively regulating LEF1 expression

MicroRNAs play an important role in regulating post-transcriptional gene expression in the progression of various human cancers. In this study, we investigated the role of microRNA-557 in human lung cancer cells. The molecular mechanism of microRNA-557 was also clarified in the proliferation and invasion of human lung cancer cells. Our results showed microRNA-557 levels were obviously decreased in clinical lung cancer specimens and lung cancer cell lines. Cell viability of A549 and NCI-H460 cells transfected with microRNA-557 mimics was significantly decreased than those transfected with negative control mimics. MicroRNA-557 promoted cell death of A549 and NCI-H460 but did not affect the cell apoptosis of lung cancer cells. Overexpression of microRNA-557 inhibited cell invasion of A549 and NCI-H460 cells. TargetScan analysis showed that microRNA-557 might target 3' untranslated region of lymphocyte enhancement factor 1, and the western blotting results showed that transfection of microRNA-557 mimics significantly decreased the levels of lymphocyte enhancement factor 1 in A549 and H460 cells. MicroRNA-557 might work as a tumor suppressor by negatively regulating the expression of lymphocyte enhancement factor 1 in lung cancer cells.

MiR-376c-3p regulates the proliferation, invasion, migration, cell cycle and apoptosis of human oral squamous cancer cells by suppressing HOXB7

PURPOSE

To test the influence of miR-376c-3p on the proliferation, invasion, migration, cell cycle and apoptosis of human oral squamous cancer cells (OSCC) and the relevant mechanism.

METHODS

We applied qRT-PCR and Western blot to compare the expression level of miR-376c-3p and HOXB7 in SCC-4, SCC-9, SCC-15, SCC-25 OSCC cell lines and 49 paired OSCC and normal oral epithelial tissue specimens were included in our present study. Also we analyzed the relative relationship of expression level between miR-376c-3p and HOXB7 in cancer tissues. Luciferase assay was used to confirm the target relationship between miR-376c-3p and HOXB7. Besides, MTT, Transwell, wound healing, colony formation and flow cytometer experiments were applied to evaluate the proliferation, cell viability, apoptosis, invasion and migration of transfected OSCC.

RESULTS

MiR-376c-3p was down-regulated while HOXB7 was up-regulated in OSCC tissues and cells than the normal ones. MiR-376c-3p directly targeted HOXB7 and reduced the expression of HOXB7. Overexpression of miR-376c-3p attenuated proliferation of SCC-9, SCC-15, SCC-24 and SCC-25 cells. Moreover, miR-376c-3p suppressed proliferation, viability, migration and invasion and induced G1/G0 arrest and cell apoptosis of SCC-25 cells. Besides, overexpression of HOXB7 efficiently abrogates these influences caused by overexpression of miR-376c-3p.

CONCLUSION

MiR-376c-3p suppresses the fission, proliferation, migration and invasion and induces cell apoptosis of OSCC via targeting HOXB7.

Downregulation of microRNA-30d promotes cell proliferation and invasion by targeting LRH-1 in colorectal carcinoma

The aberrant expression of miR-30d has been reported in several types of human malignancies. However, its biological function in colorectal cancer (CRC) remains largely unknown. In this study, we identified that miR-30d was significantly downregulated in CRC tissues compared to that observed in normal controls as detected by RT-qPCR analysis. Downregulation of miR-30d was significantly associated with aggressive clinicopathological parameters including tumor differentiation, invasive depth, TNM stage, lymph node metastasis, distant metastasis, and poor prognosis. Furthermore, functional analysis revealed that overexpression of miR-30d significantly inhibited cell proliferation, caused cell cycle arrest at the G0/G1 phase, suppressed cell migration and invasion, induced cell apoptosis in vitro, and decreased tumor growth in a xenograft mouse model. Bioinformatic analysis and dual-luciferase reporter assay revealed that liver receptor homologue-1 (LRH-1) is a direct target of miR-30d in CRC cells. Rescue assay showed that LRH-1 overexpression could restore the inhibitory effect of miR-30d on CRC cells. In addition, miR-30d overexpression suppressed the activation of key components of the Wnt/β-catenin signaling pathway, β-catenin, c-Myc and cyclin D1, which contributed to the inhibition of CRC development. Thus, our findings suggest that miR-30d functions as a tumor suppressor against CRC development and miR-30d/LRH-1/Wnt signaling may be novel potential targets for CRC treatment.

MicroRNA-219-5p Represses the Proliferation, Migration, and Invasion of Gastric Cancer Cells by Targeting the LRH-1/Wnt/β-Catenin Signaling Pathway

MicroRNAs (miRNAs) are reportedly involved in gastric cancer development and progression. In particular, miR-219-5p has been reported to be a tumor-associated miRNA in human cancer. However, the role of miR-219-5p in gastric cancer remains unclear. In this study, we investigated for the first time the potential role and underlying mechanism of miR-219-5p in the proliferation, migration, and invasion of human gastric cancer cells. miR-219-5p was found to be markedly decreased in gastric cancer tissues and cell lines compared with adjacent tissues and normal gastric epithelial cells. miR-219-5p mimics or anti-miR-219-5p was transfected into gastric cancer cell lines to overexpress or suppress miR-219-5p expression, respectively. Results showed that miR-219-5p overexpression significantly decreased the proliferation, migration, and invasion of gastric cancer cells. Conversely, miR-219-5p suppression demonstrated a completely opposite effect. Bioinformatics and luciferase reporter assays indicated that miR-219-5p targeted the 3′-untranslated region of the liver receptor homolog-1 (LRH-1), a well-characterized oncogene. Furthermore, miR-219-5p inhibited the mRNA and protein levels of LRH-1. LRH-1 mRNA expression was inversely correlated with miR-219-5p expression in gastric cancer tissues. miR-219-5p overexpression significantly decreased the Wnt/β-catenin signaling pathway in gastric cancer cells. Additionally, LRH-1 restoration can markedly reverse miR-219-5p-mediated tumor suppressive effects. Our study suggests that miR-219-5p regulated the proliferation, migration, and invasion of human gastric cancer cells by suppressing LRH-1. miR-219-5p may be a potential target for gastric cancer therapy.

Aberrant expression of miR-21, miR-376c and miR-145 and their target host genes in Merkel cell polyomavirus-positive non-small cell lung cancer

Merkel Cell Polyoma Virus (MCPyV) infection has been associated with non-small cell lung cancer (NSCLC). Viruses can manipulate cellular miRNAs or have a profound impact on cellular miRNA expression to control host regulatory pathways. In this study, we evaluated the expression profiles of cancer-associated and virally affected host microRNAs miR-21, miR-145, miR-146a, miR-155, miR-302c, miR-367 and miR-376c in a series of NSCLC tissue samples as well as in samples from “healthy” sites, distant from the tumour region that were either positive or negative for MCPyV DNA. miR-21 and miR-376c were significantly upregulated whereas miR-145 was significantly downregulated in the MCPyV+ve samples compared to the MCPyV-ve tumour samples. Overall, miR-21 and miR-376c expression was higher in tumour compared to healthy tissue samples. No association was observed between the miR-155, miR-146a, miR-302c and miR-367 levels and the presence of MCPyV. The expression of miR-21 target genes (Pten, Bcl-2, Daxx, Pkr, Timp3), miR-376c (Grb2, Alk7, Mmp9) and miR-145 (Oct-4, Sox2, Fascin1) and their associated pathways (Braf, Akt-1, Akt-2, Bax, Hif1a, p53) was altered between MCPyV+ve tumor samples and their corresponding controls. These results show a novel association between miR-21, miR-376c and miR-145 and their host target genes with the presence of MCPyV, suggesting a mechanism of virus-specific microRNA signature in NSCLC.