Strategies to use microRNAs as therapeutic targets

miRNA contributes to neuropathic pains

Neuropathic pain (NP) is a kind of chronic pain caused by direct injury to the peripheral or central nervous system (CNS). microRNAs (miRNAs) are small noncoding RNAs that mostly interact with the 3 untranslated region of messenger RNAs (mRNAs) to regulate the expression of multiple genes. NP is characterized by changes in the expression of receptors and mediators, and there is evidence that miRNAs may contribute to some of these alterations. In this review, we aimed to fully comprehend the connection between NP and miRNA; and also, to establish a link between neurology, biology, and dentistry. Studies have shown that targeting miRNAs may be an effective therapeutic strategy for the treatment of chronic pain and potential target for the prevention of NP.

Pituitary Tumorigenesis-Implications for Management

Pituitary neuroendocrine tumors (PitNETs), the third most common intracranial tumor, are mostly benign. However, some of them may display a more aggressive behavior, invading into the surrounding structures. While they may rarely metastasize, they may resist different treatment modalities. Several major advances in molecular biology in the past few years led to the discovery of the possible mechanisms involved in pituitary tumorigenesis with a possible therapeutic implication. The mutations in the different proteins involved in the Gsa/protein kinase A/c AMP signaling pathway are well-known and are responsible for many PitNETS, such as somatotropinomas and, in the context of syndromes, as the McCune-Albright syndrome, Carney complex, familiar isolated pituitary adenoma (FIPA), and X-linked acrogigantism (XLAG). The other pathways involved are the MAPK/ERK, PI3K/Akt, Wnt, and the most recently studied HIPPO pathways. Moreover, the mutations in several other tumor suppressor genes, such as menin and CDKN1B, are responsible for the MEN1 and MEN4 syndromes and succinate dehydrogenase (SDHx) in the context of the 3PAs syndrome. Furthermore, the pituitary stem cells and miRNAs hold an essential role in pituitary tumorigenesis and may represent new molecular targets for their diagnosis and treatment. This review aims to summarize the different cell signaling pathways and genes involved in pituitary tumorigenesis in an attempt to clarify their implications for diagnosis and management.

Dysregulation of miR-204-5p/APLN axis affects malignant progression and cell stemness of esophageal cancer

OBJECTIVE

This study attempted to investigate the mechanism of miR-204-5p and its downstream gene in regulating bio-functions of esophageal cancer (EC).

METHODS

Bioinformatics analysis was performed to select the mature miRNAs, mRNAs, and clinical data of EC. The miRNA-mRNA regulatory axis was predicted through bioinformatics and used Dual-luciferase analysis to verify the interaction between miR-204-5p and APLN. qRT-PCR was applied to analyze expression of miR-204-5p and APLN mRNA. Western blot was utilized to detect APLN protein expression. Functional assays like CCK-8, wound healing, Transwell, and stem cell sphere formation assays were launched to confirm proliferative, migratory, invasive and stemness of cells in different treatment groups.

RESULTS

MiR-204-5p was lowly expressed while its target gene APLN was highly expressed in tumor tissues. Besides, miR-204-5p overexpression hindered proliferation, invasion, migration, and stemness of EC cells. Additionally, dual-luciferase assay verified the interaction of miR-204-5p and APLN. MiR-204-5p could downregulate APLN level and its overexpression reduced the effect of APLN on EC cell functions.

CONCLUSION

Dysregulation of miR-204-5p/APLN axis was linked with malignant progression of EC. MiR-204-5p/APLN may be an underlying candidate for the design of anticarcinogens.

MicroRNAs in Dopamine Agonist-Resistant Prolactinoma

Dopamine agonists (DAs) are preferred for the treatment of prolactinomas and are usually very effective. Nonetheless, 20-30% of bromocriptine- and approximately 10% of cabergoline-treated individuals exhibit resistance to DAs. In addition, the mechanism underlying this phenomenon remains elusive. In this study, we summarize the major findings regarding the role of microRNAs (miRNAs) in the pathogenesis of DA-resistant prolactinoma (DARP). Currently available evidence suggests that miRNAs are usually dysregulated in DARP and that, although controversial, the dysregulated miRNAs target the transforming growth factor (TGF)-β, dopamine 2 receptor (D2R), or estradiol (E2)/estrogen receptor (ER) signaling pathways to mediate the therapeutic effect of DAs. These findings provide new incentives for research on innovative strategies for predicting patients' responsiveness to dopamine therapies and for developing treatment approaches. Unfortunately, recent studies tended to focus exclusively on the differential miRNA expression profiles between DARP and dopamine-sensitive prolactinoma, and no definitive consensus has been reached regarding the role of these miRNAs in the modulation mechanism. Therefore, current and future efforts should be directed toward the exploration of the mechanism underlying the dysregulation of miRNAs as well as of the target proteins that are affected by the dysregulated miRNAs. Furthermore, the modulation of the expression of dysregulated miRNAs, which target the D2R, TGF-β, or E2/ER signaling pathways, might be a promising alternative to treat patients with DARP and improve their prognosis.

MicroRNA-296-5p inhibits cell proliferation by targeting HMGA1 in colorectal cancer

An increasing body of evidence indicates the involvement of microRNAs (miRNAs/miRs) in the initiation and progression of colorectal cancer (CRC). miR-296-5p was recently identified as a tumor suppressor in a variety of human cancer types; however, its function in CRC remains largely unknown. The present study demonstrated that the expression of miR-296-5p was significantly downregulated in CRC tissues and cell lines. The overexpression of miR-296-5p markedly inhibited proliferation, and induced cell cycle arrest and apoptosis in CRC cells. Bioinformatics analysis suggested that high mobility group AT-hook 1 (HMGA1) may be a target of miR-296-5p in CRC cells. Further experiments showed that miR-296-5p bound the 3'-untranslated region of HMGA1 and decreased its expression in CRC cells. HMGA1 was overexpressed in CRC tissues and was inversely correlated with the expression of miR-296-5p. The restoration of HMGA1 significantly reversed the inhibitory effect of miR-296-5p on the proliferation of CRC cells. Overall, the findings of the present study indicate that miR-296-5p suppressed the progression of CRC, at least partially via targeting HMGA1. Thus, miR-296-5p is a potential target for novel therapies in CRC.

microRNA-1298 inhibits the malignant behaviors of breast cancer cells via targeting ADAM9

MicroRNAs (miRNAs) regulate the progression of human malignancy by targeting oncogenes or tumor suppressors, which are 12 promising targets for cancer treatment. Increasing evidence has suggested the aberrant expression and tumor-suppressive function of miR-1298 in cancers, however, the regulatory mechanism of miR-1298 in breast cancer (BC) remains unclear. Here, our findings showed that miR-1298 was down-regulated in BC tissues and cell lines. Lower level of miR-1298 was significantly correlated with the advanced progression of BC patients. Experimental study showed that overexpression of miR-1298 inhibited the proliferation, induced apoptosis and cell cycle arrest in BC cells. The in vivo xenograft mice model showed that highly expressed miR-1298 significantly reduced the tumor growth and metastasis. Further mechanism analysis revealed that miR-1298 bound the 3′-untranslated region (UTR) of a disintegrin and metalloproteinase 9 domain (ADAM9) and suppressed the expression of ADAM9 in BC cells. ADAM9 was overexpressed in BC tissues and inversely correlated with miR-1298. Down-regulation of ADAM9 induced apoptosis and cell cycle arrest of BC cells. Moreover, ectopic expression of ADAM9 by transiently transfecting with vector encoding the full coding sequence of ADAM9 attenuated the inhibitory effects of miR-1298 on the proliferation and cell cycle progression of BC cells. Collectively, our results illustrated that miR-1298 played a suppressive role in regulating the phenotype of BC cells through directly repressing ADAM9, suggesting the potential application of miR-1298 in the therapy of BC.

Downregulation of lncRNA H19 sensitizes melanoma cells to cisplatin by regulating the miR-18b/IGF1 axis

Long noncoding RNAs (LncRNAs) lncRNA H19 has been shown to be involved in the chemotherapy resistance of cancer cells. However, the role of lncRNA H19 in chemotherapy resistance of melanoma cells remains unknown. Here, we determined lncRNA H19, miR-18b, and insulin-like growth factor 1 (IGF1) expression by utilizing quantitative real-time PCR. Cell proliferation ability and chemosensitivity were assessed by colony formation assay and MTT assay. Flow cytometry assay was applied to detect cell apoptosis. We discovered that lncRNA H19 was upregulated, but miR-18b was downregulated in melanoma tissues and cisplatin (DDP)-resistant melanoma cells. The overall survival for the group with lower lncRNA H19 was significantly better than the group with higher H19. IGF1 mRNA level was higher in melanoma tissues than that in normal tissues. miR-18b expression level A negative correlation was observed between the expression levels of miR-18b, lncRNA H19, and IGF1 mRNA. Functionally, knockdown of lncRNA H19 sensitized resistant A375/DDP and M8/DDP cells to DDP. Silencing lncRNA H19 inhibited colony formation ability and promoted apoptosis of DDP-resistant melanoma cells, which was abrogated by miR-18b inhibition and IGF1 upregulation. Mechanistically, lncRNA H19 directly interacted with miR-18b to regulate its expression. IGF1 was identified as a target of miR-18b. These findings highlight the fact that lncRNA H19 could influence DDP-resistance by modulating the miR-18b/IGF axis in melanoma cells, suggesting a new potential therapeutic target for melanoma patient treatment.

microRNA-1296 Inhibits Glioma Cell Growth by Targeting ABL2

Aberrant expression of microRNAs (miRNAs) has been reported to play a role in tumorigenesis. Dysfunction of miR-1296 was found in a variety of cancers, however, the function of miR-1296 in the progression of glioma remains largely understood. Here, our results showed that miR-1296 was significantly down-regulated in glioma tissues and cell lines. Decreased expression of miR-1296 was associated with the tumor size, WHO grade and karnofsky performance scale (KPS) of glioma patients. Low expression of miR-1296 was significantly correlated with the shorter 5-year overall survival of glioma patients. Overexpression of miR-1296 inhibited the proliferation, colony formation, migration and induced apoptosis of glioma cells. MiR-1296 was found to bind the 3’-untranslated region (UTR) of ABL proto-oncogene 2 (ABL2) and subsequently repressed both the mRNA and protein expression of ABL2. ABL2 was overexpressed in glioma tissues and inversely correlated with that of miR-1296. Ectopic expressed ABL2 could reverse the inhibitory effects of miR-1296 on glioma cell proliferation. Our results illustrated the novel tumor-suppressive function of miR-1296 in glioma via repressing ABL2, suggesting a potential application of miR-1296 in the treatment of glioma.

MicroRNA-936 Targets JAG1 and Inhibits the Proliferation of Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Investigating the underlying molecular mechanism is essential for the treatment and prognosis of HCC. Emerging evidence suggests that microRNAs (miRNAs) play pivotal roles in cancer progression. Down-regulation of miR-936 has been found in several cancers, which serves as a tumor suppressor to inhibit the development of cancers. However, the clinical significance and functional roles of miR-936 in HCC have not been determined. To explore this, the expression of miR-936 in HCC tissues and cells was detected by RT-qPCR. Cell Counting Kit-8 (CCK-8) assay, cell migration and cell cycle analysis were performed to evaluate the effects of miR-936 on the growth of HCC cells. The targets of miR-936 were predicted using the miRDB database and confirmed by luciferase reporter experiments. The protein expression of targets was determined by western blot. The results showed that miR-936 was significantly decreased in HCC tissues and cell lines. Low expression of miR-936 was associated with the advance progression and poor survival of HCC patients (P = 0.0036). Functional study revealed that overexpression of miR-936 inhibited the proliferation, migration (decreased to ∼0.26 fold) and induced cell cycle arrested in G₁ phase (from 35.3% to 44.7%) of HCC cells. Additionally, miR-936 targeted the 3′-untranslated region (UTR) of jagged-1 (JAG1) and reduced the expression of JAG1 (decreased to ∼0.35 fold). JAG1 was found to be up-regulated in HCC tissues and was inversely correlated with the expression of miR-936 (Pearson r = −0.4633; P = 0.0007). The anti-cancer effects of miR-936 on the proliferation of HCC cells were partially reversed by the rescue of JAG1. Therefore, these results suggested that miR-936 might be a potential target for HCC treatment.

MiR-124-5p Inhibits the Progression of Gastric Cancer by Targeting MIEN1

Objective:

To observe the effect of miR-124-5p on progression of gastric cancer (GC) and explore the targeting mechanism.

Methods:

After collecting the specimens, we used real-time fluorescence quantitative PCR to detect the miR-124-5p level of GC tissue and corresponding adjacent tissue. Then MTT test and scratch wound-healing assay were hired to evaluate the influence of miR-124-5p in GC cell (SGC-803 and SGC7901) migration and proliferation ability. The binding of miR-124-5p to migration and invasion enhancer 1 (MIEN1) was detected through dual luciferase reporter gene experiment and western blot was utilized to assay the protein level of MIEN1.

Results:

Compared with adjacent tissues, miR-124-5p level in GC tissues was lower significantly. MiR-124-5p mimic inhibited the metastasis and proliferation ability of SGC7901 cells and miR-124-5p inhibitor promoted the migration and proliferation ability of SGC803 cells. In addition, miR-124-5p targeted MIEN1 and negatively modulated the MIEN1 expression in SGC-803 and SGC7901 cells. Silencing MIEN1 negatively regulated the metastasis and proliferation ability of SGC7901 cells.

Conclusion:

MiR-124-5p inhibited the GC cell proliferation and metastasis phenotypes through MIEN1, which probably becomes a novel molecular target for clinical GC treatment.

MicroRNA‑744‑5p is downregulated in colorectal cancer and targets SEPT2 to suppress the malignant phenotype

MicroRNA (miR)‑744‑5p serves a pivotal role in the progression of multiple cancers; however, the function of miR‑744‑5p in colorectal cancer (CRC) remains largely unknown. In the present study, the effects of miR‑744‑5p on the progression of CRC were analyzed and the mechanisms involved were investigated. It was revealed that miR‑744‑5p was frequently downregulated in CRC tissues and cell lines. Overexpression of miR‑744‑5p significantly inhibited the proliferation, colony formation, and promoted the apoptosis of CRC cells. Bioinformatics analysis revealed that Septin 2 (SEPT2) was a potential target of miR‑744‑5p. miR‑744‑5p bound the 3'‑untranslated region (UTR) of SEPT2 and reduced the level of SEPT2 in CRC cells. A negative correlation between the expression of miR‑744‑5p and SEPT2 was observed in CRC tissues. Overexpression of SEPT2 counteracted the suppressive effect of miR‑744‑5p on the proliferation and apoptosis of CRC cells. Collectively, these data demonstrated the functional mechanism of miR‑744‑5p by targeting SEPT2, which suggested miR‑744‑5p as a potential target for the treatment of patients with CRC.

MiR-138-5p Inhibits the Proliferation of Gastric Cancer Cells by Targeting DEK

Background

Increasing evidence suggests that microRNAs (miRNAs) play critical roles in cancer progression. Therefore, investigating the function of miRNAs that are aberrantly expressed in gastric cancer (GC) and characterizing the involved underlying mechanism are essential for the treatment of gastric cancer. MiR-138-5p was found to be down-regulated in multiple cancers, which acted as a tumor suppressor in cancer progression; however, whether and how miR-138-5p regulates the malignant behaviors of GC has not been fully understood.

Methods

The level of miR-138-5p in GC tissues and cell lines was detected by RT-qPCR. The effects of miR-138-5p on the growth of GC cells were evaluated by the in vitro Cell Counting Kit-8 (CCK-8) assay, cell apoptosis, cell cycle analysis, wound-healing assay, and in vivo xenograft mice model. The targets of miR-138-5p were predicted using the miRDB online tool, confirmed by luciferase report assay and Western blot.

Results

MiR-138-5p was frequently decreased in GC tissues and cell lines. Decreased expression of miR-138-5p was significantly associated with the lymph node metastasis of GC patients. Overexpression of miR-138-5p suppressed GC cell proliferation, migration, increased cell apoptosis as well as inhibited the tumor growth in vivo. DEK oncogene was predicted as a potential target of miR-138-5p. MiR-138-5p bound the 3'-UTR of DEK and inhibited the level of DEK in GC cells. Restoration of DEK abrogated miR-138-5p overexpression-mediated suppression of GC cell proliferation and cell cycle arrest.

Conclusion

Our results demonstrated the anti-cancer role of miR-138-5p in GC by targeting DEK, which suggested miR-138-5p as a potential therapeutic target for the treatment of patient with GC.

MicroRNA-574-3p inhibits the malignant behavior of liver cancer cells by targeting ADAM28

Liver cancer is one of the most common and aggressive tumors, and usually leads to a poor clinical outcome. Increasing evidence has demonstrated the important functions of microRNAs (miRs) in tumor progression. miR-574-3p has been reported as a tumor suppressor and potential therapeutic target in various types of cancer. However, the underlying mechanism of the effects of miR-574-3p in liver cancer remains unknown. In the present study, reverse transcription-quantitative PCR was performed to detect miR-574-3p expression in liver cancer tissues, and the influence of miR-574-3p on cell growth was evaluated using the Cell Counting Kit-8 assay, and cell migration and flow cytometry analyses. The present study revealed that miR-574-3p expression was downregulated in liver cancer tissues and cell lines. miR-574-3p overexpression, achieved by transfecting miR-574-3p mimics into liver cancer cells, reduced cell proliferation and migration, and promoted cell apoptosis. Mechanistically, ADAM metallopeptidase domain 28 (ADAM28) was identified as a miR-574-3p target via binding to the 3'-untranslated region of the ADAM28 mRNA. Gain-of-function of miR-574-3p downregulated the expression levels of ADAM28 in liver cancer cells. Additionally, overexpression of ADAM28 significantly attenuated the suppressive effect of miR-574-3p on the growth of liver cancer cells. The present results provide novel insights into the function of the miR-574-3p/ADAM28 signaling pathway in liver cancer.

miR-375-3p inhibits the progression of laryngeal squamous cell carcinoma by targeting hepatocyte nuclear factor-1β

Laryngeal squamous cell carcinoma (LSCC) is one of the most frequently diagnosed head and neck cancers worldwide. Increasing evidence suggests that microRNAs (miRNAs/miRs) regulate the progression of tumorigenesis and the malignant behaviors of cancer cells. The aim of this study was to investigate the function and underlying mechanism of miR-375-3p in LSCC. The expression of miR-375-3p in LSCC tissues and cells was detected using reverse transcription-quantitative PCR. The effects of miR-375-3p on the malignant phenotype of LSCC cells was determined using the Cell Counting Kit-8 assay and flow cytometry. The targets of miR-375-3p were predicted using the miRDB database and confirmed by the luciferase reporter assay. The results of the present study demonstrated that miR-375-3p was downregulated in LSCC tissues and cell lines. Furthermore, overexpression of miR-375-3p significantly suppressed the proliferation and cell cycle progression of LSCC cells. Overexpression of miR-375-3p also increased LSCC cell apoptosis. Mechanistical analysis indicated that miR-375-3p bound the 3′-untranslated region of the hepatocyte nuclear factor 1β (HNF1β) and decreased its expression in LSCC cells. Consistent with the role of HNF1β in glucose metabolism, overexpression of miR-375-3p significantly inhibited glucose consumption and lactate production in LSCC cells. Transfection with HNF1β notably reversed the inhibitory effect of miR-375-3p on the proliferation of LSCC cells. Collectively, these results indicate the tumor suppressive role of miR-375-3p in LSCC via HNF1β, suggesting that miR-375-3p may serve as a potential target in the treatment of LSCC.

MiR-645 regulates the proliferation and apoptosis of diffuse large B-cell lymphoma by targeting DACH1

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of malignant non-Hodgkin lymphoma cases. An increasing body of evidence has indicated the critical roles of microRNAs (miRNAs) in regulating the progression of DLBCL. In this study, we found that miR-645 was up-regulated in DLBCL tissues and cell lines. Down-regulation of miR-645 significantly inhibited the proliferation, cell cycle progression and promoted the apoptosis of DLBCL cells. Experimental study identified Dachshund family transcription factor 1 (DACH1) as a target of miR-645. MiR-645 bound the 3'-untranslated region of DACH1 and reduced the expression of DACH1 in DLBCL cells. Decreased expression of DACH1 was inversely correlated with that of miR-645 in DLBCL tissues. The promoting effect of miR-645 on the proliferation of DLBCL cells was attenuated with the overexpression of DACH1. These results demonstrated the novel mechanism of miR-645 in DLBCL, which indicated miR-645 as a potential target for the diagnosis and prognostics of DLBCL.

Correlation of miRNA expression with intensity of neuropathic pain in man

Background

Peripheral nerve injury causes changes in expression of multiple receptors and mediators that participate in pain processing. We investigated the expression of microRNAs (miRNAs) – a class of post-transcriptional regulators involved in many physiological and pathophysiological processes – and their potential role in the development or maintenance of chronic neuropathic pain following lingual nerve injury in human and rat.

Methods

We profiled miRNA expression in Sprague-Dawley rat and human lingual nerve neuromas using TaqMan® low-density array cards. Expression of miRNAs of interest was validated via specific probes and correlated with nerve injury-related behavioural change in rat (time spent drinking) and clinical pain (visual analogue scale (VAS) score). Target prediction was performed using publicly available algorithms; gene enrichment and pathway analysis were conducted with MetaCore. Networks of miRNAs and putative target genes were created with Cytoscape; interaction of miRNAs and target genomes in rat and human was displayed graphically using CircosPlot.

Results

rno-miR-138 was upregulated in lingual nerve of injured rats versus sham controls. rno-miR-138 and rno-miR-667 expression correlated with behavioural change at day 3 post-injury (with negative (rno-miR-138) and positive (rno-miR-667) correlations between expression and time spent drinking). In human, hsa-miR-29a was downregulated in lingual nerve neuromas of patients with higher pain VAS scores (painful group) versus patients with lower pain VAS scores (non-painful). A statistically significant negative correlation was observed between expression of both hsa-miR-29a and hsa-miR-500a, and pain VAS score.

Conclusions

Our results show that following lingual nerve injury, there are highly significant correlations between abundance of specific miRNAs, altered behaviour and pain scores. This study provides the first demonstration of correlations between human miRNA levels and VAS scores for neuropathic pain and suggests a potential contribution of specific miRNAs to the development of chronic pain following lingual nerve injury. Putative targets for candidate miRNAs include genes related to interleukin and chemokine receptors and potassium channels.

MiR-539 inhibits the malignant behavior of breast cancer cells by targeting SP1

The aberrant expression of microRNAs (miRNAs) is involved in the initiation and progression of human cancers. In our study, we found that miR-539 was down-regulated in breast cancer tissues and cell lines. Decreased expression of miR-539 was significantly associated with lymph node metastasis in patients with breast cancer. Overexpression of miR-539 inhibited the proliferation and promoted apoptosis of breast cancer cells. Moreover, highly expressed miR-539 significantly suppressed the epithelial-mesenchymal transition (EMT) and sensitized cells to cisplatin treatment. Mechanistically, miR-539 was found to target the specificity protein 1 (SP1) and down-regulated the expression of SP1 in breast cancer cells. Knockdown of miR-539 consistently increased the expression of SP1. The expression of miR-539 in breast cancer tissues was negatively correlated with the expression of SP1. Restoration of SP1 significantly attenuated the inhibitory effect of miR-539 on the proliferation of breast cancer cells. Taken together, our results indicate that miR-539 has a tumor suppressive role in breast cancer via targeting SP1, suggesting miR-539 as a promising target for the diagnosis of breast cancer.

Regulation of cell growth and migration by miR-96 and miR-183 in a breast cancer model of epithelial-mesenchymal transition

Breast cancer is the most commonly diagnosed malignancy in women, and has the second highest mortality rate. Over 90% of all cancer-related deaths are due to metastasis, which is the spread of malignant cells from the primary tumor to a secondary site in the body. It is hypothesized that one cause of metastasis involves epithelial-mesenchymal transition (EMT). When epithelial cells undergo EMT and transition into mesenchymal cells, they display increased levels of cell proliferation and invasion, resulting in a more aggressive phenotype. While many factors regulate EMT, microRNAs have been implicated in driving this process. MicroRNAs are short noncoding RNAs that suppress protein production, therefore loss of microRNAs may promote the overexpression of specific target proteins important for EMT. The goal of this study was to investigate the role of miR-96 and miR-183 in EMT in breast cancer. Both miR-96 and miR-183 were found to be downregulated in post-EMT breast cancer cells. When microRNA mimics were transfected into these cells, there was a significant decrease in cell viability and migration, and a shift from a mesenchymal to an epithelial morphology (mesenchymal-epithelial transition or MET). These MET-related changes may be facilitated in part by the regulation of ZEB1 and vimentin, as both of these proteins were downregulated when miR-96 and miR-183 were overexpressed in post-EMT cells. These findings indicate that the loss of miR-96 and miR-183 may help facilitate EMT and contribute to the maintenance of a mesenchymal phenotype. Understanding the role of microRNAs in regulating EMT is significant in order to not only further elucidate the pathways that facilitate metastasis, but also identify potential therapeutic options for preventing or reversing this process.

miR-140-5p targeted FGF9 and inhibited the cell growth of laryngeal squamous cell carcinoma

Increasing evidence has suggested that microRNAs (miRNAs) play critical roles in the initiation and development of cancers. Here, we found that miR-140-5p was significantly downregulated in both laryngeal squamous cell carcinoma (LSCC) tissues and cell lines. Decreased expression of miR-140-5p was significantly associated with the metastasis of LSCC. Overexpression of miR-140-5p inhibited proliferation and induced apoptosis of LSCC cells. Mechanistically, the fibroblast growth factor 9 (FGF9) was identified as the target of miR-140-5p. miR-140-5p bound the 3′-untranslated region (3′-UTR) of FGF9 and suppressed the expression of FGF9 in LSCC cells. Additionally, the level of FGF9 was upregulated in LSCC tissues and negatively correlated with the expression of miR-140-5p. Restoration of FGF9 attenuated the suppressive role of miR-140-5p in regulating the growth of LSCC cells. Collectively, these results indicated that the tumor suppressive function of miR-140-5p in LSCC was partially exercised by modulating the expression of FGF9.

Analysis of whole genome-wide microRNA transcriptome profiling in invasive pituitary adenomas and non-invasive pituitary adenomas

Background

Dysregulation of microRNAs (miRNAs) plays a critical role during the occurrence and progress of pituitary adenomas (PAs). However, the roles of miRNAs in the invasiveness of PA are poorly understood. This study aims to more comprehensively and specific define the relationship between altered miRNA and PA invasion.

Methods

The differential expression of miRNAs (DEMs) between invasive PAs (IPAs) and non-invasive PAs (NPAs) was explored by RNA sequencing and which functions were analyzed by gene ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG). The miRNA-mRNA network was predicted with bioinformatics.

Results

We identified 31 upregulated miRNAs and 24 downregulated miRNAs in IPAs compared with NPAs. GO analysis and KEGG pathway analysis showed the DEMs were mainly associated with cell proliferation and cell cycle pathway. In addition, on the count of predicted miRNA-mRNA network, two hub miRNAs were identified.

Conclusions

Our results demonstrate the miRNA-mRNA network in detail, which suggest that miRNA may be a promising target in diagnosis and therapy for IPAs.

MiR-204-3p Inhibited the Proliferation of Bladder Cancer Cells via Modulating Lactate Dehydrogenase-Mediated Glycolysis

MicroRNAs (miRNAs) are endogenous non-coding RNAs that negatively regulate the expression of downstream targeted mRNAs. Increasing evidence has suggested that miRNAs act as tumor suppressors or oncogenes to interfere the progression of cancers. Here, we showed that miR-204-3p was decreased in bladder cancer tissues and cell lines. Down-regulation of miR-204-3p was significantly associated with a poor prognosis in bladder cancer patients. Overexpression of miR-204-3p inhibited proliferation and induced apoptosis in bladder cancer cells. Furthermore, miR-204-3p was found to bind to the 3′-untranslated region (UTR) of the lactate dehydrogenase (LDHA), which consequently reduced the expression of both mRNA and protein of LDHA. Interestingly, overexpression of miR-204-3p decreased glucose consumption and lactate production of bladder cancer cells. Overexpression of LDHA relieved the growth inhibition and cell apoptosis enhancement by miR-204-3p in bladder cancer cells. These results demonstrated that miR-204-3p negatively modulated the proliferation of bladder cancer cells via targeting LDHA-mediated glycolysis. MiR-204-3p might be a promising candidate for designing anticancer medication.

Silencing Of hsa_circ_0008450 Represses Hepatocellular Carcinoma Progression Through Regulation Of microRNA-214-3p/EZH2 Axis

Purpose

Circular RNA (circRNA) hsa_circ_0008450 has been shown to be up-regulated in hepatocellular carcinoma (HCC). However, the functional role of hsa_circ_0008450 and its molecular mechanism are still unknown.

Patients and methods

We used qRT-PCR and Western blot to examine the expression levels of hsa_circ_0008450, microRNA-214-3p (miR-214-3p), and enhancer of zeste homolog 2 (EZH2) protein. CCK8 assay and wound healing assay were used to detect cell viability and cell migration capability. Cell apoptosis was assessed by flow cytometry. Luciferase reporter assay was used to explore the interaction among hsa_circ_0008450, miR-214-3p, and EZH2.

Results

hsa_circ_0008450 was significantly increased in HCC tissues and cells. Furthermore, knockdown of hsa_circ_0008450 in HCC cells inhibited cell proliferation, invasion, and migration. Mechanically, hsa_circ_0008450 promoted the expression of EZH2 protein through sponging miR-214-3p. Knockdown of circ_0008450 suppressed tumorigenesis of HCC cells in vivo.

Conclusion

Knockdown of hsa_circ_0008450 inhibits HCC progression by regulating miR-214-3p/EZH2 axis. This study suggests that hsa_circ_0008450 may serve as a novel target for the treatment of HCC.

Lineage-dependent role of miR-410-3p as oncomiR in gonadotroph and corticotroph pituitary adenomas or tumor suppressor miR in somatotroph adenomas via MAPK, PTEN/AKT, and STAT3 signaling pathways

PURPOSE

miR-410-3p plays opposite roles in different cancers and may act as an oncomiR or tumor suppressor miR. The purpose of this study was to assess the role of miR-410-3p in somatotroph, gonadotroph, and corticotroph pituitary adenomas.

METHODS

Tissue samples were obtained from 75 patients with pituitary adenoma. miR-410-3p expression was assessed using qRT-PCR performed on RNA isolated from fresh frozen samples. In vitro experiments were performed on cell lines derived from somatotroph (GH3), gonadotroph (RC-4B/C), and corticotroph (AtT-20) pituitary tumors. Cells were transfected with synthetic mimic of miR-410-3p or non-targeting scrambled-miR control. Subsequently, proliferation assays and transwell invasion assays were performed. The expression of cyclin D1, E1, and B1 in cells after transfection was determined using qRT-PCR. The activation of MAPK, PTEN/AKT and STAT3 signaling pathways were assessed using western blot.

RESULTS

We have found that the level of expression of miR-410-3p differs in particular types of pituitary adenomas. miR-410-3p significantly upregulates proliferation and invasiveness of RC-4B/C and AtT-20 cells, while inhibiting GH3 cells. We observed that the levels of cyclin B1 upon transfection with miR-410-3p mimic were increased in RC-4B/C and AtT-20, yet decreased in GH3 cells. We have shown that miR-410-3p promoted the activation of MAPK, PTEN/AKT, and STAT3 signaling pathways in RC-4B/C and AtT-20 cells, but suppressed their activity in GH3 cells.

CONCLUSIONS

miR-410-3p acts as an oncomiR in gonadotroph and corticotroph adenoma cells, while as a tumor suppressor miR in somatotroph adenoma cells.

miR‑185 regulates the growth of osteosarcoma cells via targeting Hexokinase 2

MicroRNAs (miRNAs) have been proposed as potential prognostic and diagnostic biomarkers in numerous types of cancer, including osteosarcoma (OS), which is the most common bone malignancy. The present study revealed that the expression of miR‑185 was downregulated in OS tissues and cells. Overexpression of miR‑185 significantly suppressed the proliferation and migration of OS cells. To further investigate the functional roles of miR‑185 in OS, the downstream targets of miR‑185 were predicted using the microRNA.org database. The results revealed that in cancer cells, hexokinase 2 (HK2), the rate‑limiting enzyme of glycolysis, was a potential target of miR‑185. Molecular analysis indicated that miR‑185 binds to the 3'‑untranslated region of HK2 mRNA. Overexpressed miR‑185 downregulated the mRNA and protein levels of HK2 in OS cells. In addition, an inverse correlation between the expression of miR‑185 and HK2 was reported in OS. Consistent with the downregulation of HK2 induced by miR‑185, overexpression of HK2 in OS cells significantly attenuated the inhibitory effects of miR‑185 on glucose consumption and lactate production, while depletion of miR‑185 promoted the glycolysis of OS cells. Additionally, restoration of HK2 abolished the inhibitory effects of miR‑185 on the proliferation of OS cells. In summary, these results revealed that miR‑185 suppressed the glucose metabolism of OS cells; thus, miR‑185 may be considered as a promising therapeutic target for the treatment of OS.

MiR-505 suppressed the growth of hepatocellular carcinoma cells via targeting IGF-1R

Hepatocellular carcinoma (HCC) is one of the most common cancers globally. An increasing body of evidence has demonstrated the critical function of microRNAs (miRNAs) in the initiation and progression of human cancers. Here, we showed that miR-505 was down-regulated in HCC tissues and cell lines. Reduced expression of miR-505 was significantly correlated with the worse prognosis of HCC patients. Overexpression of miR-505 suppressed the proliferation, colony formation and induced apoptosis of both HepG2 and Huh7 cells. Further mechanism study uncovered that miR-505 bound the 3'-untranslated region (3'-UTR) of the insulin growth factor receptor (IGF-1R) and inhibited the expression of IGF-1R in HCC cells. The down-regulation of IGF-1R by miR-505 further suppressed the phosphorylation of AKT at the amino acid S473. Consistently, the abundance of glucose transporter (GLUT) 1 (GLUT1) was reduced with the overexpression of miR-505. Down-regulation of GLUT1 by miR-505 consequently attenuated the glucose uptake, lactate production and ATP generation of HCC cells. Collectively, our results demonstrated the tumor suppressive function of miR-505 possibly via inhibiting the glycolysis of HCC cells. These findings suggested miR-505 as an interesting target for designing anti-cancer strategy in HCC.

Chidamide suppresses the glycolysis of triple negative breast cancer cells partially by targeting the miR‑33a‑5p‑LDHA axis

Triple negative breast cancer (TNBC) is one of the most aggressive types of breast cancer and has a poor prognosis. Therefore, the development of novel drugs and understanding the molecular mechanisms that may contribute to the initiation and development of TNBC are urgently required. Chidamide, a histone deacetylase inhibitor, has been reported as possessing anti‑cancer properties in several cancers, however, the function of chidamide in TNBC remains to be elucidated. The present study revealed that chidamide inhibited the proliferation, colony formation and migration of TNBC cells. Experiments investigating the underlying mechanism revealed that chidamide upregulated the expression of microRNA (miR)‑33a‑5p in TNBC cells via RT‑qPCR. Luciferase reporter assay demonstrated that miR‑33a‑5p was bound to the 3'‑untranslated region of lactate dehydrogenase A (LDHA) and decreased the expression of LDHA in TNBC cells. In addition, chidamide suppressed the expression of LDHA and significantly decreased the glycolysis of TNBC cells. Collectively, the results of the present study demonstrated that chidamide reprogramed glucose metabolism, partially by targeting the miR‑33a‑5p/LDHA pathway, in TNBC. These findings indicate that chidamide may be a promising novel drug in the treatment of patients with TNBC.

miR-383 Inhibited the Cell Cycle Progression of Gastric Cancer Cells via Targeting Cyclin E2

Increasing evidence has suggested the key roles of miRNAs in the initiation and progression of human cancers. miR-383 was downregulated and played a suppressive role in a variety of cancers; however, the function of miR-383 in gastric cancer remains unclear. In this study, we found that the expression of miR-383 was significantly reduced in gastric cancer tissues and correlated with the advanced progression of these cancer patients. Functional analysis showed that overexpression of miR-383 inhibited the proliferation and upregulated the apoptosis of gastric cancer cells. Furthermore, cyclin E2 was predicted as the target of miR-383 using the bioinformatics database. miR-383 bound the 3'-untranslated region of cyclin E2 and decreased the expression of cyclin E2 in gastric cancer cells. Upregulation of cyclin E2 was observed in gastric cancer tissues compared with the normal controls. Highly expressed cyclin E2 was inversely correlated with the level of miR-383 in gastric cancer tissues. Consistent with the decreased expression of cyclin E2 with miR-383, transfection of miR-383 induced cell cycle arrest at G1 phase in gastric cancer cells. Restoration of cyclin E2 significantly reversed the inhibitory effect of miR-183 on gastric cancer cell proliferation. Collectively, our results characterized the suppressive role of miR-383 in gastric cancer partially through targeting cyclin E2.

miR‑221‑3p promotes the cell growth of non‑small cell lung cancer by targeting p27

Emerging evidence suggests the critical function of microRNAs in regulating the growth of cancer cells. In the present study, it was demonstrated that miR-221-3p was overexpressed in non-small cell lung cancer (NSCLC) tissues and cell lines compared with that noted in the normal controls. Downregulation of miR-221-3p suppressed the proliferation, colony formation and invasion of NSCLC cells. To further understand the molecular mechanisms underlying the potential oncogenic function of miR-221-3p in NSCLC, the downstream targets of miR-221-3p were predicted using bioinformatic databases. The prediction suggested the cell cycle regulator p27 as one of the targets of miR-221-3p. Molecular experiments showed that miR-221-3p was able to bind with the 3′-untranslated region (UTR) of p27 and decreased the expression of p27 in NSCLC cells. Consistent with the suppressive role of p27 in controlling cell cycle progression, overexpression of miR-221-3p decreased the expression of p27 and promoted cell cycle progression from G1 to S phase. Collectively, our findings identified miR-221-3p as a novel regulator of NSCLC cell growth via modulating the expression of p27.

A STUDY OF THE ROLE OF MICRORNA IN PITUITARY ADENOMA

MicroRNAs are a new class of small non-coding RNAs, a length of 18–22 nucleotides that play a decisive role as posttranscriptional regulators of gene expression. Due to the large number of genes, regulated microRNAs, microRNAs are involved in many cellular processes. The study of the impairment of the expression of the target genes of microRNA, often associated with changes in important biological characteristics, provides a significant understanding of the role of microRNAs in oncogenesis. New evidence suggests that aberrant microRNA expression or dysregulation of endogenous microRNAs affects the onset and development of tumors, including adenomas of the pituitary gland. In this review, the significance of some microRNAs in the pathology of the pituitary adenoma will be assessed, as well as data on the study of microRNAs as therapeutic targets and new biomarkers.

Pathogenesis of non-functioning pituitary adenomas

The pathogenesis of non functioning pituitary adenomas (NFPA) is a complex process involving several factors, from molecular to genetic and epigenetic modifications, where tumor suppressor genes, oncogenes, cell cycle derangements have been demonstrated to play an important role. MicroRNAs (miRNAs) have also been identified as possible players in NFPA tumorigenesis and pituitary stem cells have been investigated for their potential role in pituitary tumor initiation. However, a critical role for paracrine signalling has also been highlighted. This review focuses on the current knowledge on the involvement of these factors in NFPA pathogenesis.

MicroRNAs in pituitary tumors

Since the presence of microRNAs was first observed in normal pituitary, the majority of scientific publications addressing their role and the function of microRNAs in the pituitary have been based on pituitary tumor studies. In this review, we briefly describe the involvement of microRNAs in the synthesis of pituitary hormones and we present a comprehensive inventory of microRNA suppressors and inducers of pituitary tumors. Finally, we summarize the functional role of microRNAs in tumorigenesis, progression and aggressiveness of pituitary tumors, mechanisms contributing to the regulation (transcription factors, genomic modifications or epigenetic) or modulation (pharmacological treatment) of microRNAs in these tumors, and the interest of thoroughly studying the expression of miRNAs in body fluids.

Screening circular RNA expression patterns following focal cerebral ischemia in mice

Circular RNAs (circRNAs) have been demonstrated to act as microRNA (miRNA) sponges and they play important roles in regulating gene expression through a circRNA-miRNA-gene pathway. The specific roles of circRNAs in the pathogenesis of cerebral ischemia, however, are still unclear. Thus, the aim of this study is to determine circRNA expression profiles in the ischemic brain after stroke, which was induced by 45 min of transient middle cerebral artery occlusion (MCAO). The results from the circRNA microarrays revealed that 1027 circRNAs were significantly altered 48 hours after reperfusion in the ischemic brain compared with the sham group. Among them, 914 circRNAs were significantly upregulated, and the remaining 113 were significantly downregulated. In addition, the expressions of the three selected circRNAs, mmu_circRNA_40001, mmu_circRNA_013120, and mmu_circRNA_40806, were verified using quantitative real-time polymerase chain reaction (qRT-PCR). After predicting their target genes, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were further used to predict the associated significant cell signaling pathways and functions. The results show that the most enriched pathways are associated with the Rap1 signaling pathway and the Hippo signaling pathway, which regulate cell survival and death. Finally, we constructed an interaction network of circRNA-miRNA-target genes, including 13 miRNAs and their corresponding genes, indicating that changes in circRNA are associated with genes related with brain injury and recovery. In conclusion, circRNAs are complicated in the pathological development of brain injury after stroke, suggesting novel diagnostic and therapeutic targets for stroke therapy.

Increased expression of the microRNA 106b~25 cluster and its host gene MCM7 in corticotroph pituitary adenomas is associated with tumor invasion and Crooke's cell morphology

PURPOSE

MCM7 (minichromosome maintenance complex component 7), a DNA replication licensing factor, is a host gene for the oncogenic miR-106b~25 cluster. It has been recently revealed as a relevant prognostic biomarker in a variety of cancers, including pituitary adenomas. The purpose of this study was to assess whether miR-106b~25 and MCM7 levels correlate with tumor invasiveness in a cohort of ACTH-immunopositive adenomas.

METHODS

Tissue samples were obtained intraoperatively from 25 patients with pituitary adenoma. Tumor invasiveness was assessed according to the Knosp grading scale. MCM7, Ki-67 and TP53 levels were assessed by immunohistochemical staining, while the expression of miR-106b-5p, miR-93-5p, miR-93-3p and miR-25-3p were measured using quantitative real-time PCR performed on RNA isolated from FFPE tissues.

RESULTS

We have found a significant increase in MCM7 and Ki-67 labeling indices in invasive ACTHomas. Moreover, MCM7 was ubiquitously overexpressed in Crooke's cell adenomas. The expression of miR-93-5p was significantly elevated in invasive compared to noninvasive tumors. In addition, all four microRNAs from the miR-106b~25 cluster displayed marked upregulation in Crooke's cell adenomas. Remarkably, MCM7 and miR-106b-5p both strongly correlated with Knosp grade. A combination of MCM7 LI and miR-106b~25 cluster expression was able to accurately differentiate invasive from noninvasive tumors and had a significant discriminatory ability to predict postoperative tumor recurrence/progression.

CONCLUSIONS

miR-106b~25 and its host gene MCM7 are potential novel biomarkers for invasive ACTH-immunopositive pituitary adenomas. Additionally, they are both significantly upregulated in rare Crooke's cell adenomas and might therefore contribute to their aggressive phenotype.

Reduction of miR-21 induces SK-N-SH cell apoptosis and inhibits proliferation via PTEN/PDCD4

MicroRNA (miR/miRNA)-21 is a well-known oncogenic miRNA that is overexpressed in various types of tumors. The tumor-suppressor genes programmed cell death 4 (PDCD4) and phosphatase tensin homologue (PTEN), are targets of miR-21, and are underexpressed in several types of cancer. However, the expression of miR-21 and its target genes in neuroblastoma (NB) remains unclear. In the present study, a miR-21 inhibitor oligonucleotide was transfected into the SK-N-SH cell line, and the expression of miR-21, PTEN and PDCD4 was detected through quantitative polymerase chain reaction analysis. Western blotting was used to examine levels of PTEN, PDCD4 and caspase-3 proteins. The expression of PTEN and PDCD4 in the SK-N-SH cell line transfected with the miR-21 inhibitor was significantly increased compared with untransfected SK-N-SH and negative control-transfected cells. Cell proliferation was inhibited and the apoptotic ratio was significantly increased in miR-21 inhibitor-transfected cells compared with untransfected SK-N-SH and negative control-transfected cells. Western blot analysis revealed a significant increase in caspase-3 expression compared with untransfected SK-N-SH and negative control-transfected cells. The results of the present study indicate that miR-21 may serve an oncogenic role in the cellular processes underlying NB development and thus may be a novel therapeutic target for the treatment of patients with NB.

Overexpression of MicroRNA-216a Suppresses Proliferation, Migration, and Invasion of Glioma Cells by Targeting Leucine-Rich Repeat-Containing G Protein-Coupled Receptor 5

Increasing studies have suggested that microRNAs (miRNAs) are involved in the development of gliomas. MicroRNA-216a has been reported to be a tumor-associated miRNA in many types of cancer, either as an oncogene or as a tumor suppressor. However, little is known about the function of miR-216a in gliomas. The present study was designed to explore the potential role of miR-216a in gliomas. We found that miR-216a was significantly decreased in glioma tissues and cell lines. Overexpression of miR-216a significantly suppressed the proliferation, migration, and invasion of glioma cells. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) was identified as a target gene of miR-216a in glioma cells by bioinformatics analysis, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction, and Western blot analysis. Moreover, miR-216a overexpression inhibited the Wnt/β-catenin signaling pathway. The restoration of LGR5 expression markedly reversed the antitumor effect of miR-216a in glioma cells. Taken together, these findings suggest a tumor suppressor role for miR-216a in gliomas, which inhibits glioma cell proliferation, migration, and invasion by targeting LGR5. Our study suggests that miR-216a may serve as a potential therapeutic target for future glioma treatment.