MicroRNAs (miRNAs) in cancer invasion and metastasis: therapeutic approaches based on metastasis-related miRNAs

MicroRNA-19a regulates milk fat metabolism by targeting SYT1 in bovine mammary epithelial cells

MicroRNAs (miRNAs) are important post-transcriptional factors involved in the regulation of gene expression and play crucial roles in biological processes related to milk fat metabolism. Our previous study revealed that miR-19a expression was significantly higher in the mammary epithelial cells of high-milk fat cows than in those of low-milk fat cows. However, the precise molecular mechanisms underlying these differences remain unclear. In this study, we found a high expression of miR-19a in the mammary tissues of dairy cows. The regulatory effects of miR-19a on bovine mammary epithelial cells (BMECs) were analyzed using cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays, which demonstrated that miR-19a significantly inhibited BMEC proliferation. Transfection of the miR-19a mimic into BMECs significantly upregulated the expression of milk fat marker genes LPL, SCAP, and SREBP1, promoting triglyceride (TG) synthesis and lipid droplet formation, whereas the miR-19a inhibitor exhibited the opposite function. TargetScan and miRWalk predictions revealed that synaptotagmin 1 (SYT1) is a target gene of miR-19a. A dual luciferase reporter gene assay, RT-qPCR, and western blot analyses revealed that miR-19a directly targets the 3'-untranslated region (UTR) of SYT1 and negatively regulates SYT1 expression. Functional validation revealed that overexpression of SYT1 in BMECs significantly downregulated the expression of LPL, SCAP, and SREBP1, and inhibited TG synthesis and lipid droplet formation. Conversely, the knockdown of SYT1 had the opposite effect. Altogether, miR-19a plays a crucial role in regulating the proliferation and differentiation of BMECs and regulates biological processes related to TG synthesis and lipid droplet formation by suppressing SYT1 expression. These findings provide a strong foundation for further research on the functional mechanisms underlying milk fat metabolism in dairy cows.

microRNA-382 as a tumor suppressor? Roles in tumorigenesis and clinical significance

MicroRNAs (miRNAs) are small single-stranded RNAs belonging to a class of non-coding RNAs with an average length of 18-22 nucleotides. Although not able to encode any protein, miRNAs are vastly studied and found to play role in various human physiologic as well as pathological conditions. A huge number of miRNAs have been identified in human cells whose expression is straightly regulated with crucial biological functions, while this number is constantly increasing. miRNAs are particularly studied in cancers, where they either can act with oncogenic function (oncomiRs) or tumor-suppressors role (referred as tumor-suppressor/oncorepressor miRNAs). miR-382 is a well-studied miRNA, which is revealed to play regulatory roles in physiological processes like osteogenic differentiation, hematopoietic stem cell differentiation and normal hematopoiesis, and liver progenitor cell differentiation. Notably, miR-382 deregulation is reported in pathologic conditions, such as renal fibrosis, muscular dystrophies, Rett syndrome, epidural fibrosis, atrial fibrillation, amelogenesis imperfecta, oxidative stress, human immunodeficiency virus (HIV) replication, and various types of cancers. The majority of oncogenesis studies have claimed miR-382 downregulation in cancers and suppressor impact on malignant phenotype of cancer cells in vitro and in vivo, while a few studies suggest opposite findings. Given the putative role of this miRNA in regulation of oncogenesis, assessment of miR-382 expression is suggested in a several clinical investigations as a prognostic/diagnostic biomarker for cancer patients. In this review, we have an overview to recent studies evaluated the role of miR-382 in oncogenesis as well as its clinical potential.

Aberrant promoter hypermethylation of miR-335 and miR-145 is involved in breast cancer PD-L1 overexpression

PD-L1 is one of the most important immune checkpoint molecules in breast cancer that plays an important role in suppressing the immune system when confronted with tumor cells and is regulated by various microRNAs. Among them, microRNA-335-3p and microRNA-145-5p, regulated by DNA methylation, have tumor suppressor activities. We studied the role of miR-335 and -145 on PD-L1 suppression in breast cancer. The expression of miR-355 and miR-145 was significantly downregulated in BC tissues and cell lines compared to their controls, and their downregulation was negatively correlated with PD-L1 overexpression. In-silico and luciferase reporter systems confirmed that miR-335 and -145 target PD-L1. In BC tissues and cell lines, cancer-specific methylation was found in CpG-rich areas upstream of miR-335 and-145, and up-regulation of PD-L1 expression was connected with hypermethylation (r = 0.4089, P = 0.0147, and r = 0.3373, P = 0.0475, respectively). The higher levels of miR-355 and -145 in BC cells induced apoptosis, arrested the cell cycle, and reduced proliferation significantly. In summary, we found that miR-335 and -145 are novel tumor suppressors inactivated in BC, and these miRs may serve as potential therapeutic targets for breast cancer treatment.

A Single Variant in Pri-miRNA-155 Associated with Susceptibility to Hereditary Breast Cancer Promotes Aggressiveness in Breast Cancer Cells

Variants in genes encoding for microRNAs have been associated with their deregulation in breast cancer (BC). Sequencing of microRNAs deregulated in BC was performed using DNA from Chilean patients with a strong family history and negative for mutations in BRCA1/BRCA2. Seventeen variants were identified, three of which were selected for a case-control association study: rs376491654 (miR-335), rs755634302 (miR-497), and rs190708267 (miR-155). For rs190708267 C>T, the heterozygous T allele was detected in four BC cases and absent in controls, while homozygous TT cases were not detected. Variants were modelled in silico, cloned in a plasmid, expressed in BC cell lines, and functional in vitro assays were performed. Overexpression of the miR-155-T allele increased mature miR-155-5p levels in both BC cell lines, suggesting that its presence alters pre-miR-155 processing. Moreover, BC cells overexpressing the miR-155-T allele showed increased proliferation, migration, and resistance to cisplatin-induced death compared to miR-155-C overexpressing cells. Of note, the 3′UTR of APC, GSK3β, and PPP1CA genes, all into the canonical Wnt signaling pathway, were identified as direct targets. APC and GSK3β mRNA levels decreased while PP1 levels increased. These results suggest a pathogenic role of the variant rs190708267 (miR-155) in BRCA 1/2 negative BC, conferring susceptibility and promoting traits of aggressiveness.

Knockdown of miR-372-3p Inhibits the Development of Diabetic Cardiomyopathy by Accelerating Angiogenesis via Activating the PI3K/AKT/mTOR/HIF-1α Signaling Pathway and Suppressing Oxidative Stress

Background

DCM is the most common and malignant complication of diabetes. It is characterized by myocardial dilatation, hypertrophy, fibrosis, ventricular remodeling, and contractile dysfunction. Although many studies have demonstrated the function of miRNAs in the progression of DCM, but the specific role of miR-372-3p in DCM remains unknown.

Methods

C57/BL6J mice were used to construct mouse models of DCM by intraperitoneal injection of STZ (50 mg/kg/d) for 5 consecutive days. Then the mice were randomly divided into model group (intramyocardial injection of empty lentivirus) and miR-372-3p KD group (intramyocardial injection of miR-372-3p KD lentivirus at 10⁹/mouse). Besides, the control group (injection of 0.9% normal saline) was also set up. LY294002, a PI3K inhibitor, was employed in the current study. Western blotting, immunofluorescence staining, quantitative ultrasound method, Masson's trichrome staining, and bioinformatics analysis were performed.

Results

It was found that miR-372-3p KD significantly improved left ventricular dysfunction and cardiac hypertrophy in DCM mice. Furthermore, it also improved myocardial interstitial fibrosis and remodeling in DCM mice. Immunofluorescence staining and RT-qPCR revealed that miR-372-3p KD might accelerate cardiac remodeling by increasing angiogenesis in DCM mice. Western blotting results revealed that miR-372-3p was an upstream target of the PI3K/AKT-mTOR and HIF-1α signals, as well as NOX2, NOX4, which were responsible for angiogenesis in DCM mice. Besides, the in vitro experiment showed that LY294002 markedly diminished the increased expression levels of p-PI3K, AKT, p-mTOR, p-P70S6K, HIF-1α, NOX2, and NOX4 in the model group and the miR-372-3p KD group, suggesting that PI3K signaling pathway and oxidative stress are involved in miR-372-3p KD-induced angiogenesis in HG-stimulated C166 cells.

Conclusions

MiR-372-3p KD inhibits the development of DCM via activating the PI3K/AKT/mTOR/HIF-1α signaling pathway or suppressing oxidative stress. This offers an applicable biomarker for DCM treatment.

miRNA-mRNA associations with inosine monophosphate specific deposition in the muscle of Jingyuan chicken

1. Inosine monophosphate (IMP), is an essential component for meat flavour and microRNAs (miRNAs) play a vital role in its post-transcriptional regulation. However, the mechanism of how miRNA expression affects muscle-specific IMP deposition is unclear.2. The following study performed transcriptome sequencing and bioinformatics analysis of breast and leg muscle, which have significantly different IMP content in Jingyuan chicken. The differential miRNA-mRNAs were screened out and correlation analysis with IMP content was performed.3. A total of 39 differentially expressed miRNAs (DE miRNAs) and 666 differentially expressed mRNAs (DE mRNAs) were identified between breast muscles and leg muscles. Using miRNA-mRNA integrated analysis, 29 miRNA-target gene pairs were obtained, composed of 13 DE miRNAs and 28 DE mRNAs. Next, purine metabolism, glycolysis/gluconeogenesis, pyruvate metabolism and the biosynthesis of amino acid pathways as necessary for muscle IMP-specific deposition were identified. The differentially expressed gene PKM2, which was significantly enriched in all four pathways, is involved in IMP anabolism in the form of energy metabolism and enzyme activity regulation. The correlation analysis suggested that the gga-miR-107-3p-KLHDC2 negative interaction may be a key regulator in IMP deposition.4. This study explores the functional mechanism of IMP-specific deposition in Jingyuan chicken muscles at the miRNA and mRNA levels and highlights multiple candidate miRNAs and mRNAs for molecular-assisted breeding.

FTX Regulated miR-153-3p/FOXR2 to Promote Cisplatin Resistance in Ovarian Cancer

Purpose

The present study was aimed at exploring the role of FTX in cisplatin (DDP) resistance in ovarian cancer (OC).

Methods

QPCR was applied to evaluate mRNA expression in OC tissue and cells. CCK-8 assay was conducted to evaluate cell proliferation. Transwell chamber assay was performed to evaluate invasion of SKOV3/DDP cells. The protein expression was evaluated via western blot assay. Flow cytometry was performed to evaluate the apoptosis of SKOV3/DDP cells.

Results

The expression of FTX in DDP-resistant cells was observably higher in contrast to DDP-sensitive cells and normal ovarian cells. FTX was higher expressed in DDP-resistant tissues by comparison with DDP-sensitive tissues. Knockdown of FTX obviously suppressed the proliferation ability invasion ability of SKOV3/DDP cells. Knockdown of FTX obviously enhanced apoptosis of SKOV3/DDP cells. miR-153-3p was proved to be directly regulated by FTX via the luciferase reporter assays. By comparison with normal cells, miR-153-3p was lower expressed in OC cells. miR-153-3p was lower expressed in SKOV3/DDP cells in contrast to SKOV3 cells. More interestingly, FTX reversed the inhibiting influence of miR-153-3p on cisplatin resistance of OC cells. Moreover, miR-153-3p was proved to directly regulate FOXR2. Knockdown of miR-153-3p attenuated the inhibitory influence of knockdown FOXR2 on cisplatin resistance of OC cells.

Conclusion

FTX regulated miR-153-3p/FOXR2 to promote cisplatin resistance via inhibiting the apoptosis and promoting the viability and invasion in OC.

MicroRNA-744-5p suppresses tumorigenesis and metastasis of osteosarcoma through the p38 mitogen-activated protein kinases pathway by targeting transforming growth factor-beta 1

Osteosarcoma (OS) is the most common malignant bone tumor in children and adolescents. Accumulating evidence has revealed that microRNAs (miRNAs) play a crucial role in the progression of OS. In this study, we found that miR-744-5p was the least expressed miRNA in patients with OS by analyzing GSE65071 from the GENE EXPRESSION OMNIBUS (GEO) database. Through real-time quantitative PCR (qRT-PCR), western blotting, colony formation assay, 5-Ethynyl-2-Deoxyuridine (EdU) incorporation assay, transwell migration, and invasion assays, we demonstrated its ability to inhibit the proliferation, migration, and invasion of OS cells in vitro. According to the luciferase reporter assay, transforming growth factor-β1 (TGFB1) was negatively regulated by miR-744-5p and reversed the effects of miR-744-5p on OS. Subcutaneous tumor-forming animal models and tail vein injection lung metastatic models were used in animal experiments, and it was found that miR-744-5p negatively regulated tumor growth and metastasis in vivo. Furthermore, rescue assays verified that miR-744-5p regulates TGFB1 expression in OS. Further experiments revealed that the p38 MAPK signaling pathway is involved in the miR-744-5p/TGFB1 axis. Generally, this study suggests that miR-744-5p is a negative regulator of TGFB1 and suppresses OS progression and metastasis via the p38 MAPK signaling pathway.

MicroRNAs and drug resistance in colorectal cancer with special focus on 5-fluorouracil

Colorectal cancer is globally one of the most common cancers in all age groups. The current chemotherapy combinations for colorectal cancer treatment include 5-fluorouracil-based regimens; however, drug resistance remains one of the main reasons for chemotherapy failure and disease recurrence. Many studies have determined colorectal cancer chemoresistance mechanisms such as drug efflux, cell cycle arrest, DNA damage repair, apoptosis, autophagy, vital enzymes, epigenetic, epithelial-mesenchymal transition, stem cells, and immune system suppression. Several microRNAs affect drug resistance by regulating the drug resistance-related target genes in colorectal cancer. These drug resistance-related miRNAs may be used as promising biomarkers for predicting drug response or as potential therapeutic targets for treating patients with colorectal cancer. This work reviews and discuss the role of selected microRNAs in 5-fluorouracil resistance and their molecular mechanisms in colorectal cancer.

MALAT1 promotes malignant pleural mesothelioma by sponging miR-141-3p

The aim of this study was to clarify the role of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in proliferation, migration, and invasion of malignant pleural mesothelioma (MPM) cells. The quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to detect the expression of MALAT1 in MPM cell lines. The effects of MALAT1 and miR-141-3p on the proliferation, migration, and invasion of MPM cells were studied through a series of in vitro cellular experiments. The flow cytometry was utilized to detect the cell apoptosis. The dual‐luciferase reporter assay was employed to explore the binding relationship among MALAT1, miR-141-3p, and YES-associated protein 1 (YAP1). MALAT1 was overexpressed in MPM cell lines, while its knockdown significantly inhibited the cell proliferation, migration, and invasion, and increased the number of MPM cells in the G0/G1 phase. In addition, MALAT1 could directly bind to miR-141-3p and inhibit its expression. YAP1 has been identified as a downstream target of miR-141-3p, and its expression level was inhibited by miR-141-3p. MALAT1 can be used as a competitive endogenous RNA (ceRNA) to regulate the YAP1-Hippo signaling pathway through miR-141-3p, promote the proliferation, migration, and invasion of MPM cells, and provide a new target for the therapy of MPM.

Nanoparticle-complexed antimiRs for inhibiting tumor growth and metastasis in prostate carcinoma and melanoma

Background

MiRNAs act as negative regulators of gene expression through target mRNA degradation or inhibition of its translation. In cancer, several miRNAs are upregulated and play crucial roles in tumorigenesis, making the inhibition of these oncomiRs an interesting therapeutic approach. This can be achieved by directly complementary single-stranded anti-miRNA oligonucleotides (antimiRs). A major bottleneck in antimiR therapy, however, is their efficient delivery. The nanoparticle formation with polyethylenimine (PEI) may be particularly promising, based on the PEI’s ability to electrostatically interact with oligonucleotides. This leads to their protection and supports delivery. In the present study, we explore for the first time PEI for antimiR formulation and delivery. We use the branched low molecular weight PEI F25-LMW for the complexation of different antimiRs, and analyse tumor- and metastasis-inhibitory effects of PEI/antimiR complexes in different tumor models.

Results

In prostate carcinoma, transfection of antimiRs against miR-375 and miR-141 leads to tumor cell inhibition in 2D- and 3D-models. More importantly, an in vivo tumor therapy study in prostate carcinoma xenografts reveals anti-tumor effects of the PEI/antimiR complexes. In advanced melanoma and metastasis, we identify by a microRNA screen miR-150 as a particularly relevant oncomiR candidate, and validate this result in vitro and in vivo. Again, the systemic application of PEI/antimiR complexes inhibiting this miRNA, or the previously described antimiR-638, leads to profound tumor growth inhibition. These effects are associated with the upregulation of direct miRNA target genes. In a melanoma metastasis mouse model, anti-metastatic effects of PEI/antimiR treatment are observed as well.

Conclusions

We thus describe PEI-based complexes as efficient platform for antimiR therapy, as determined in two different tumor entities using in vivo models of tumor growth or metastasis. Our study also highlights the therapeutic relevance of miR-375, miR-141, miR-150 and miR-638 as target miRNAs for antimiR-mediated inhibition.

MiR-370-5p inhibits the progression of breast cancer via targeting LUC7L3

Breast cancer is one of the most common malignancies and one of the leading causes of cancer-induced mortality among women. Over the past decades, the occurrence of breast cancer has been a significant increase. As documented in numerous researches, microRNAs (miRNAs) play vital roles in a wide range of biological processes associated with the occurrence and development of breast cancer. Nevertheless, the role of miR-370-5p in breast cancer remains obscure, and the possible molecular regulatory mechanism needs to be further explored. In this study, our results delineated that miR-370-5p was downregulated in breast cancer tissues and cell lines. Besides, miR-370-5p overexpression suppressed cell proliferation and invasion in breast cancer. MiR-370-5p downregulation exerted an opposite result. In addition, LUC7L3 was identified as a target gene for miR-370-5p. Similar with the results induced by miR-370-5p overexpression, LUC7L3 knockdown attenuated the proliferation and invasion ability of breast cancer cells. Moreover, the alternation of LUC7L3 expression reversed the regulatory effects of miR-370-5p on cell phenotypes in breast cancer. Overall, miR-370-5p may exert antitumor effect on breast cancer. Hence, miR-370-5p may serve as a novel therapeutic marker for the treatment of patients with breast cancer.

Hypoxia Activates SOX5/Wnt/β-Catenin Signaling by Suppressing MiR-338-3p in Gastric Cancer

MicroRNAs are known to be important in a variety of cancer types. The specific expression and roles of miR-338-3p in the context of gastric cancer, however, remains largely unknown. In this study, we found that miR-338-3p was expressed significantly lower in established/primary human gastric cancer cells than that in human gastric epithelial cells; miR-338-3p is also decreased in human gastric cancer tissues and was positively associated with the worse prognosis of patients with gastric cancer. Enforced expression of miR-338-3p could inhibit cell growth, survival, and proliferation, while inducing cell apoptosis. In addition, miR-338-3p negatively regulated SOX5 expression through directly binding to the 3′-untranslated region of SOX5, and an inverse correlation was found between miR-338-3p and SOX5 messenger RNA expression in gastric cancer tissues. Furthermore, miR-338-3p-induced inactivation of Wnt/β-catenin signaling was greatly abrogated by SOX5 upregulation. Finally, we found that hypoxic conditions were linked with reduced miR-338-3p expression in the context of gastric cancer. In conclusion, miR-338-3p acts as a tumor suppressor in gastric cancer, possibly by directly targeting SOX5 and blocking Wnt/β-catenin signaling. These findings might provide novel therapeutic targets for gastric cancer.

Therapeutically Significant MicroRNAs in Primary and Metastatic Brain Malignancies

Simple Summary

The overall survival of brain cancer patients remains grim, with conventional therapies such as chemotherapy and radiotherapy only providing marginal benefits to patient survival. Cancers are complex, with multiple pathways being dysregulated simultaneously. Non-coding RNAs such as microRNA (miRNAs) are gaining importance due to their potential in regulating a variety of targets implicated in the pathology of cancers. This could be leveraged for the development of targeted and personalized therapies for cancers. Since miRNAs can upregulate and/or downregulate proteins, this review aims to understand the role of these miRNAs in primary and metastatic brain cancers. Here, we discuss the regulatory mechanisms of ten miRNAs that are highly dysregulated in glioblastoma and metastatic brain tumors. This will enable researchers to develop miRNA-based targeted cancer therapies and identify potential prognostic biomarkers.

Abstract

Brain cancer is one among the rare cancers with high mortality rate that affects both children and adults. The most aggressive form of primary brain tumor is glioblastoma. Secondary brain tumors most commonly metastasize from primary cancers of lung, breast, or melanoma. The five-year survival of primary and secondary brain tumors is 34% and 2.4%, respectively. Owing to poor prognosis, tumor heterogeneity, increased tumor relapse, and resistance to therapies, brain cancers have high mortality and poor survival rates compared to other cancers. Early diagnosis, effective targeted treatments, and improved prognosis have the potential to increase the survival rate of patients with primary and secondary brain malignancies. MicroRNAs (miRNAs) are short noncoding RNAs of approximately 18–22 nucleotides that play a significant role in the regulation of multiple genes. With growing interest in the development of miRNA-based therapeutics, it is crucial to understand the differential role of these miRNAs in the given cancer scenario. This review focuses on the differential expression of ten miRNAs (miR-145, miR-31, miR-451, miR-19a, miR-143, miR-125b, miR-328, miR-210, miR-146a, and miR-126) in glioblastoma and brain metastasis. These miRNAs are highly dysregulated in both primary and metastatic brain tumors, which necessitates a better understanding of their role in these cancers. In the context of the tumor microenvironment and the expression of different genes, these miRNAs possess both oncogenic and/or tumor-suppressive roles within the same cancer.

MiR-27a-3p Targeting GSK3β Promotes Triple-Negative Breast Cancer Proliferation and Migration Through Wnt/β-Catenin Pathway

BACKGROUND

Dysregulation of microRNAs (miRNAs) was found to play crucial roles in varieties of cancers, which affect tumor proliferation and migration. MiR-27a-3p has been identified as a tumor-related miRNA in liver cancer, lung cancer, and colorectal cancer. However, the function of miR-27a-3p in triple-negative breast cancer (TNBC) and its possible molecular mechanisms have still not been elucidated.

METHODS

QRT-PCR technique was used to detect the expression of miR-27a-3p in TNBC and normal breast cell lines or the effects of miR-27a-3p knockdown and overexpression in TNBC cell lines. Proliferation and migration were measured by CCK-8 method, colony formation, wound healing, and Transwell assays, respectively. Furthermore, we used a dual-luciferase reporter gene assay and Western blot analysis to identify GSK3β as a target of miR-27a-3p.

RESULTS

In this study, we found that miR-27a-3p expression was significantly elevated in TNBC cell lines. Database analysis suggested that TNBC patients with a high expression of miR-27a-3p have poorer overall survival possibilities. Overexpression of miR-27a-3p promotes TNBC cells proliferation, colony formation, and cell migration in vitro. Nevertheless, dual-luciferase reporter result showed that miR-27a-3p directly targeted the 3'-UTR regions of GSK3β mRNA and negatively regulated its expression. Lastly, we demonstrated that miR-27a-3p inactivates Wnt/β-catenin signaling pathway via targeting GSK3β.

CONCLUSION

These results indicate that expression of miR-27a-3p was highly expressed in TNBC and promoted tumor progression through attenuating GSK3β and may have a potential molecular-targeted strategy for TNBC therapy.

miR-602 Mediates the RASSF1A/JNK Pathway, Thereby Promoting Postoperative Recurrence in Nude Mice with Liver Cancer

Purpose

At present, there are few studies on the mechanisms underlying postoperative recurrence of liver cancer, and the mechanism of action of miR-602 in postoperative recurrence of liver tumors is not clear. Our goals were to investigate the effects of miR-602 on the expression of the Ras-associated domain family 1A (RASSF1A) gene and the regulation of primary and recurrent hepatic tumors to clarify the molecular mechanisms of miR-602 in postoperative hepatocellular carcinoma.

Methods

We constructed a mouse liver orthotopic tumor model and a mouse liver recurrent tumor model. We measured the expression levels of the RASSF1A gene and then analyzed the effects of miR-602 on the regulation of RASSF1A. We transiently transfected the miR-602 gene into cells that stably overexpressed RASSF1A and examined relevant indicators to elucidate the mechanisms by which miR-602 regulates the RASSF1A/c-Jun N-terminal kinase (JNK) pathway in recurrence and dormancy in liver cancer.

Results

RASSF1A expression was inversely related to that of JNK, activating transcription factor 2 (ATF-2), and c-Jun in SMMC7721 cells stably transfected with the RASSF1A gene and in recurrent mouse tumor tissues. After transient transfection of cells with miR-602 mimic or miR-602 inhibitor, the expression of miR-602 was inversely related to that of RASSF1A.

Conclusion

MiR-602 might inhibit the JNK signaling pathway by inhibiting the expression of RASSF1A, thereby promoting recurrence of liver cancer after surgery. The low expression levels of miR-602 in liver cancer tissues were closely related to postoperative recurrence; they could be used as a marker to judge the prognosis of patients with liver cancer.

miR-623 suppresses cell proliferation, migration and invasion through direct inhibition of XRCC5 in breast cancer

Background/Aims: MicroRNAs (miRNAs) are short, non-coding RNA molecules that control gene expression trough negative translational regulation. MiR-623 is a tumor suppressor, and it’s function and mechanism in breast cancer has not been reported.

Results: Exogenous overexpression of miR-623 suppressed cell proliferation, migration and invasion, meanwhile, but promoted cell apoptosis. MiR-623 knockdown displayed opposite results. Overexpression of miR-623 resulted in the downregulation of CDK4/6 as well as the inhibition of the phosphatidylinositol-3-kinase (PI3K)/Akt and Wnt/β-Catenin signaling pathways. MiR-623 knockdown displayed opposite results. Results of the reporter assay revealed that the luciferase activity was decreased in XRCC5-wt cells, suggesting that miR-623 could directly combine with 3’ UTR of XRCC5. MiR-623 significantly suppressed XRCC5 expression, which is critical for miR-623-induced proliferation and migration block in breast cancer cells.

Conclusion: miR-623 suppressed cell proliferation, migration and invasion through downregulation of cyclin dependent kinases and inhibition of the phosphatidylinositol-3-kinase (PI3K)/Akt and Wnt/β-Catenin pathways by targeting XRCC5.

Methods: miR-623 was either overexpressed in breast cancer cell lines through exogenous transfection or knocked down by specific siRNA. Cell proliferation, migration and invasion were examined using CCK-8, colony formation and transwell assay. The direct target of miR-623 was verified using luciferase reporter gene assay.

miR-1224-5p inhibits the proliferation and invasion of ovarian cancer via targeting SND1

Emerging evidences have indicated that abnormal expression of microRNAs (miRNAs) contributed to carcinogenesis of ovarian cancer. However, the molecular mechanism of many aberrant expressed miRNAs was not known. Here, we discovered that miR-1224-5p was a downregulated miRNA in ovarian cancer via bioinformatic analysis and RT-qPCR. It was found that upregulation of miR-1224-5p inhibited cell proliferation and invasion ability of ovarian cancer cells. SND1, a well-characterized oncogene, was predicted as a target gene of miR-1224-5p. The western blotting, dual luciferase reporter assay, RNA-binding protein immunoprecipitation assay, and RT-qPCR demonstrated SND1 as a target gene of miR-1224-5p in ovarian cancer. MiR-1224-5p inhibited the expression of mesenchymal markers and increased the expression of epithelial markers in ovarian cancer cells via targeting SND1, indicating miR-1224-5p was involved in epithelial mesenchymal transition. The rescue assay manifested that miR-1224-5p-regulated cell proliferation and invasion mainly rely on downregulation of SND1 in ovarian cancer cells. In conclusion, our study revealed a direct regulatory association between miR-1224-5p and SND1 and their involvement in ovarian carcinogenesis.

MicroRNA-877 is downregulated in cervical cancer and directly targets MACC1 to inhibit cell proliferation and invasion

Previously, a number of microRNAs (miRNAs) have been reported to be dysregulated in cervical cancer, and dysregulated miRNAs may play crucial roles in the development and progression of cervical cancer. Hence, investigating the detailed roles of miRNAs that are aberrantly expressed in cervical cancer and the underlying molecular mechanisms is essential for early diagnosis and effective therapeutic approaches. miRNA-877 (miR-877) was found to be downregulated in hepatocellular carcinoma and renal cell carcinoma, and function as a tumor-suppressive miRNA. However, how miR-877 exerts an effect in cervical cancer progression and its underlying molecular mechanisms remains to be elucidated. In the current study, reverse transcription-quantitative PCR was performed to determine miR-877 expression in cervical cancer tissues and cell lines. The effects of miR-877 overexpression on cervical cancer cell proliferation and invasion were evaluated using MTT and Transwell cell invasion assays. In the present study, miR-877 was significantly downregulated in cervical cancer tissues and cell lines, and the decreased expression levels of miR-877 were significantly associated with increased International Federation of Gynecology and Obstetric stage as well as increased lymph node metastasis in patients with cervical cancer. Upregulation of miR-877 using miR-877 mimics resulted in the decreased proliferation and invasion of cervical cancer cells. Metastasis-associated in colon cancer-1 (MACC1) was assessed using bioinformatics analyses to determine whether it could be a potential target gene of miR-877, and the results were confirmed using a luciferase reporter assay. Furthermore, MACC1 was markedly upregulated in cervical cancer tissues, and its level was negatively correlated with the miR-877 level. Overexpression of miR-877 resulted in decreased expression levels of MACC1 in cervical cancer cells at both the mRNA and protein levels. In addition, the functional effects of MACC1 knockdown were similar to those induced by upregulated miR-877 in cervical cancer cells. MACC1 restored miR-877 overexpression-mediated suppression of cervical cancer cell proliferation and invasion. In conclusion, miR-877 may play an antitumor role in cervical cancer by directly targeting MACC1, which suggests that this miRNA may be a promising therapeutic target for the treatment of patients with such an aggressive gynecological cancer.

Extracellular vesicles from osteosarcoma cell lines contain miRNAs associated with cell adhesion and apoptosis

Osteosarcoma is the most common primary bone tumor during childhood and adolescence. Several reports have presented data on serum biomarkers for osteosarcoma, but few reports have analyzed circulating microRNAs (miRNAs). In this study, we used next generation miRNA sequencing to examine miRNAs isolated from microvesicle-depleted extracellular vesicles (EVs) derived from six different human osteosarcoma or osteoblastic cell lines with different degrees of metastatic potential (i.e., SAOS2, MG63, HOS, 143B, U2OS and hFOB1.19). EVs from each cell line contain on average ~300 miRNAs, and ~70 of these miRNAs are present at very high levels (i.e., >1000 reads per million). The most prominent miRNAs are miR-21-5p, miR-143-3p, miR-148a-3p and 181a-5p, which are enriched between 3 and 100 fold and relatively abundant in EVs derived from metastatic SAOS2 cells compared to non-metastatic MG63 cells. Gene ontology analysis of predicted targets reveals that miRNAs present in EVs may regulate the metastatic potential of osteosarcoma cell lines by potentially inhibiting a network of genes (e.g., MAPK1, NRAS, FRS2, PRCKE, BCL2 and QKI) involved in apoptosis and/or cell adhesion. Our data indicate that osteosarcoma cell lines may selectively package miRNAs as molecular cargo of EVs that could function as paracrine agents to modulate the tumor micro-environment.

MicroRNA-625 inhibits the progression of non‑small cell lung cancer by directly targeting HOXB5 and deactivating the Wnt/β-catenin pathway

Numerous microRNAs (miRs) are dysregulated in non‑small cell lung cancer (NSCLC), serving pivotal roles in its formation and progression. miR‑625 is dysregulated in several types of human cancer, but its involvement in the formation and development of NSCLC remains poorly understood. In the present study, we aimed to investigate miR‑625 expression in NSCLC and its role in regulating NSCLC cell behavior. miR‑625 expression in NSCLC tissues and cell lines was detected using reverse transcription‑quantitative polymerase chain reaction. The effects of miR‑625 overexpression on NSCLC cell proliferation, apoptosis, migration and invasion in vitro were assessed using an MTT assay, flow cytometry, and cell migration and invasion assays, respectively. The effects of miR‑625 upregulation on NSCLC growth were evaluated in an in vivo xenograft model. The molecular mechanisms underlying the tumor‑suppressing roles of miR‑625 in NSCLC were explored in detail. miR‑625 expression was determined to be downregulated in NSCLC tissues and cell lines. This decreased expression was associated with advanced clinical features and poor overall survival of patients with NSCLC. Exogenous miR‑625 expression suppressed NSCLC cell proliferation, migration and invasion, and induced apoptosis in vitro. miR‑625 upregulation hindered NSCLC tumor growth in vivo. Homeobox B5 (HOXB5) was proposed to be the direct target gene of miR‑625 in NSCLC cells. The tumor‑suppressing effects of HOXB5 silencing were similar to those of miR‑625 overexpression in NSCLC cells. In rescue experiments, HOXB5 overexpression partially reversed the inhibitory effects of miR‑625 in NSCLC cells. miR‑625 upregulation directly targeted HOXB5 to deactivate the Wnt/β‑catenin signaling pathway in NSCLC cells in vitro and in vivo. miR‑625 was determined to be associated with HOXB5 suppression and Wnt/β‑catenin pathway deactivation, which in turn inhibited the aggressive behavior of NSCLC cells in vitro and in vivo.

Host and MTB genome encoded miRNA markers for diagnosis of tuberculosis

MicroRNAs (miRNAs) are a class of noncoding RNA molecules which are involved in various cellular and physiological processes. Previously, studies have identified several miRNAs that are potential diagnostic biomarkers for various infectious diseases including tuberculosis. We have performed small RNA sequencing using the Ion Torrent PGM platform in extra pulmonary tuberculosis (EPTB) subject's serum samples to identify circulating miRNAs during mycobacterium tuberculosis (MTB) infection. Our analysis identified 20 circulating miRNAs upregulated and 5 miRNAs downregulated during MTB infection in patient's serum. In addition, we have identified 6 MTB genome encoded miRNAs upregulated in EPTB patient's serum samples. Taqman based qRT-PCR analysis of host-genome encoded (hsa-miR-146a-5p and hsa-miR-125b-5p) and MTB genome encoded (MTB-miR5) miRNAs showed increased expression in a cohort of 52 healthy, pulmonary tuberculosis (PTB) and extra pulmonary tuberculosis (EPTB) patients serum samples. Our study identified for the first time a panel of host and MTB genome specific differentially expressed circulating miRNAs in serum samples of an Indian patient cohort with tuberculosis infection with a potential as a non-invasive diagnostic biomarker for tuberculosis infection.

miR‑802 inhibits the aggressive behaviors of non‑small cell lung cancer cells by directly targeting FGFR1

Emerging reports have revealed that several microRNAs (miRNAs) are abnormally expressed in non‑small cell lung cancer (NSCLC). miRNAs have been identified as oncogenes or tumor suppressors, and regulate various biological processes including oncogenesis and development. miR‑802 is dysregulated in multiple types of human cancer, and exerts tumor‑suppressive or promoting roles. However, the expression levels and functional roles of miR‑802 in NSCLC remain largely unknown. In the present study, miR‑802 expression was demonstrated to be decreased in NSCLC tissues and cell lines. A low miR‑802 expression was significantly correlated with the tumor stage, lymph node metastasis and brain metastasis in NSCLC patients. Restoring miR‑802 expression inhibited NSCLC cell proliferation and colony formation, induced cell apoptosis, decreased cell migration and invasion in vitro, and hindered in vivo tumor growth. Mechanistically, fibroblast growth factor receptor 1 (FGFR1) was confirmed as the target gene of miR‑802 in NSCLC cells. In addition, FGFR1 silencing mimicked the tumor‑suppressing roles of miR‑802 upregulation in NSCLC cells. Furthermore, rescue experiments revealed that FGFR1 reintroduction rescued the miR‑802‑induced inhibition of the malignant phenotypes in NSCLC cells. Notably, miR‑802 was able to deactivate the phosphoinositide 3‑kinase (PI3K)/AKT serine/threonine kinase (Akt)/mammalian target of rapamycin (mTOR) pathway in NSCLC cells in vitro and in vivo. Overall, these results demonstrated that miR‑802 could downregulate FGFR1 expression, thereby deactivating the PI3K/Akt/mTOR pathway and inhibiting the malignant development of NSCLC. Thus, miR‑802 may be a therapeutic candidate for patients with NSCLC.

miR-503 is down-regulated in osteosarcoma and suppressed MG63 proliferation and invasion by targeting VEGFA/Rictor

We analyzed the expression of miR-503 in osteosarcoma tissues (OS) and discussed the clinical significance of our findings. To provide a theoretical basis for clinical applications, prognosis prediction and treatment of osteosarcoma, we studied the biological function of miR-503 and its mechanism in MG63 osteosarcoma cells. Real-time polymerase chain reaction (PCR) was used to detect the expression of miR-503 in 45 OS tissues and 20 osteochondroma tumors, analyzing the relationship between clinical pathology and follow-up data. Cox multivariate analysis revealed the clinical and pathological features of the osteosarcoma index and the influence of miR-503 expression on OS prognosis. To observe the effect on cell proliferation and invasion, MG-63 cells were transfected with miR-503. The TargetScan and PicTar bioinformatics method was used to analyze the probable target gene of miR-503 and, combined with the function of the target genes, resulted in a final validation of related pathways. miR-503 was significantly down-regulated in primary OS samples (26/45, 57.8%). The median miR-503 expression level in osteosarcoma was two-fold lower than that in osteochondroma (median expression 6.4 and 13.09, respectively, P< 0.05). The less-expressed miR-503 was associated with Enneking stage (p= 0.004) and invasion (p= 0.015) of OC. Patients with low miR-503 expression had poorer overall survival time. In the multivariate analysis, miR-503 was a significant prognostic factor (P= 0.010). miR-503 can inhibit proliferation and invasion in the MG63 cell line. Using bioinformatics, VEGFA and Rictor were determined to be the likely downstream target genes of miR-503. VEGFA, Rictor, Akt and Erk1/2 were negatively regulated by the overexpression of miR-503. In conclusion, miR-503 has significant tumor-suppressor biological activity and is thus likely to become a new target for the treatment of osteosarcoma.

Expression analysis of miR-221-3p and its target genes in horses

BACKGROUND

A microRNA (miRNA) is a small non-coding RNA (ncRNA) approximately 20 nucleotides long and it affects gene expression through mRNA cleavage or translational repression. Horses (Equus caballus) have been domesticated and bred to enhance their speed for racing. It has been studied extensively with genetic diversity, origins and evolution.

OBJECTIVES

We examined expression patterns of miR-221-3p and its target gene CDKN1C in various horse tissues.

METHODS

We used bioinformatic tools to examine target gene, seed region and evolutionary conservation of miR-221-3p. The expression patterns of miR-221-3p and its target gene CDKN1C were analyzed by quantitative polymerase chain reaction (qPCR).

RESULTS

Among eight tissues of horse, miR-221-3p was highly expressed in cerebellum and spleen. On the other hand, only medulla was highly expressed in CDKN1C gene.

CONCLUSION

Our study provides expression data of miR-221-3p and CDKN1C gene in horse and suggests the fundamental information for future studies in relation to functional importance.

The potential role of Ets-1 and miR-326 in CD19+B cells in the pathogenesis of patients with systemic lupus erythematosus

OBJECTIVES

The aim of this study was to investigate the B cell-associated transcription factors, Ets-1 and microRNA, miR-326 in systemic lupus erythematosus (SLE) patients, and their correlation with the pathogenesis of SLE.

METHOD

A total of 44 SLE patients and 20 healthy controls were enrolled in this research, all patients fulfilled the American College of Rheumatology classification criteria for SLE. The mRNA expression of Ets-1 and miR-326 in CD19⁺B cells from SLE patients were examined by qRT-PCR. The percentages of CD19⁺CD138⁺plasma cells were analyzed by Flow cytometry.

RESULTS

We found decreased expression of Ets-1 mRNA in SLE patients compared with the healthy controls ([0.228 (0.145, 0.507)] vs [0.583 (0.452, 0.763)], p = 0.001),while increased expression of miR-326 mRNA in CD19⁺B cells SLE patients compared with the healthy controls([1.092 (0.457, 2.855)] vs [0.685 (0.274, 0.819)], p = 0.008). The percentage of CD19⁺CD138⁺plasma cells in SLE patients was higher than that of healthy controls (0.55 ± 0.21% vs 0.36 ± 0.21%, p = 0.002). Moreover, a negative correlation between expression of Ets-1 mRNA and miR-326 mRNA in CD19⁺B cells was detected (r = - 0.334, p = 0.027). A significant association between the occurrences of CD19⁺CD138⁺plasma cells and the levels of Ets-1 mRNA and miR-326 mRNA was observed (r = - 0.417, p = 0.005 and r = 0.482, p = 0.001, respectively).

CONCLUSIONS

Our results suggest that miR-326 might promote B cells differentiation by targeting Ets-1, a negative regulator of B cells differentiation and therefore participate in the pathogenesis of SLE.

Investigation of the clinical significance and molecular mechanism of miR-21-5p in hepatocellular carcinoma: A systematic review based on 24 studies and bioinformatics investigation

To investigate the prospective roles and the clinicopathological application of microRNA-21-5p (miR-21-5p) in hepatocellular carcinoma (HCC), the present review is based on 24 studies and bioinformatics investigation. Firstly, HCC-associated miR-21-5p data were aggregated from literature databases and two public genomic data repositories, including the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). Potential target genes of miR-21-5p in HCC were identified using TCGA and GEO, Natural Language Processing and 14 online software packages. The oncogenic roles of these target genes was probed for understanding using Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis. Hub genes were further investigated by protein-protein interaction network (PPI) analysis. Comprehensive meta-analysis, including 10 microarrays from GEO datasets, 13 literature studies and TCGA-based RNA sequencing data, indicated a reliable diagnostic capacity of miR-21-5p [area under the curve (AUC), 0.887; sensitivity, 0.78% and specificity, 0.79%]. The healthy control group (AUC, 0.926; sensitivity, 0.87% and specificity, 0.82%) demonstrated high diagnostic capacity of miR-21-5p compared with the chronic hepatitis B infection group (AUC, 0.904; sensitivity, 0.75% and specificity, 0.84%). A total of 10 significant enrichment pathways were indicated by KEGG analysis, with cytokine-cytokine receptor interaction exhibiting the highest score. A total of 5 genes, hepatocyte growth factor, forkhead box O1 (FOXO1), thrombospondin 1, estrogen receptor 1 (ESR1) and C-X-C motif chemokine ligand 12 were selected from 39 overlapping genes, according to the PPI network. Target genes were assembled in GO terms associated with ‘response to chemical stimulus’, ‘cell surface’ and ‘growth factor binding’. In particular, low expression of FOXO1 and ESR1 was associated with miR-21-5p expression. In conclusion, upregulated expression of miR-21-5p may be a functional regulator of the metabolism or apoptosis in HCC and a novel tumor marker for the early diagnosis of HCC.

miR-133b, a particular member of myomiRs, coming into playing its unique pathological role in human cancer

MicroRNAs, a family of single-stranded and non-coding RNAs, play a crucial role in regulating gene expression at posttranscriptional level, by which it can mediate various types of physiological and pathological process in normal developmental progress and human disease, including cancer. The microRNA-133b originally defined as canonical muscle-specific microRNAs considering their function to the development and health of mammalian skeletal and cardiac muscles, but new findings coming from our group and others revealed that miR-133b have frequently abnormal expression in various kinds of human cancer and its complex complicated regulatory networks affects the tumorigenicity and development of malignant tumors. Very few existing reviews on miR-133b, until now, are principally about its role in homologous cluster (miR-1, −133 and -206s), however, most of constantly emerging new researches now are focused mainly on one of them, so In this article, to highlight the unique pathological role of miR-133b playing in tumor, we conduct a review to summarize the current understanding about one of the muscle-specific microRNAs, namely miR-133b, acting in human cancer. The review focused on the following four aspects: the overview of miR-133b, the target genes of miR-133b involved in human cancer, the expression of miR-133b and regulatory mechanisms leading to abnormal expression of miR-133b.

MicroRNA-154 functions as a tumor suppressor in non-small cell lung cancer through directly targeting B-cell-specific Moloney murine leukemia virus insertion site 1

Lung cancer remains the leading cause of cancer-associated mortality in China and worldwide. Increasing numbers of studies have demonstrated that microRNAs (miRNAs/miRs) have vital functions in numerous developmental processes and tumorigenesis. The aim of the present study was to investigate miR-154 expression in non-small cell lung cancer (NSCLC), and to explore the roles of miR-154 in the carcinogenesis and progression of this cancer. Reverse transcription-polymerase chain reaction (RT-qPCR) was performed to detect miR-154 expression in NSCLC tissues and cell lines. In addition, cell proliferation assay, migration and invasion assays were adopted to investigate the functional roles of miR-154 in NSCLC. Bioinformatics analysis, luciferase reporter assay, RT-qPCR and western blot analysis were used to explore the potential targets of miR-154 in NSCLC. According to the results, miR-154 was significantly downregulated in NSCLC tissues and cell lines. Restoration of miR-154 expression inhibited proliferation, migration and invasion of NSCLC cells. In addition, B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI-1) was identified as a direct target gene of miR-154 in NSCLC. In conclusion, miR-154 may function as a tumor suppressor in NSCLC, partly by regulating BMI-1, and the modulation of miR-154 expression represents a potential strategy for the treatment of NSCLC patients.

microRNA-26a induces a mitochondrial apoptosis mediated by p53 through targeting to inhibit Mcl1 in human hepatocellular carcinoma

Aim

We have previously found that microRNA-26a (miR-26a) is a potential tumor suppressor in hepatocellular carcinoma (HCC). In this study, we further explored the roles of miR-26a in HCC apoptosis.

Methods

miR-26a expression levels were detected in HCC tissues by real-time PCR. Statistical analysis was performed to explore the correlation between miR-26a expression and apoptotic cells and the antiapoptotic protein levels. In vitro assays were performed to investigate the roles of miR-26a in HCC apoptosis. The immunohistochemical staining analysis, Western blot, and luciferase reporter assay were performed to evaluate the relationship between miR-26a and its potential upstream regulating and downstream target genes. The potential mechanism of the combination treatment of interferon-α1b (IFN-α1b) and 5-fluorouracil (5-FU) was explored by in vitro and in vivo assays.

Results

miR-26a levels were significantly associated with the number of apoptotic cells and inversely correlated with the protein levels of Bcl-2, Bcl-xL, and Mcl1 in HCC tissues. Furthermore, miR-26a was proved to induce the mitochondrial apoptosis in vitro by directly targeting to inhibit Mcl1 in HCC cells. Moreover, p53 was demonstrated to mediate miR-26a-induced apoptosis, by activating its promoter in HCC. Meanwhile, the combination treatment of IFN-α1b and 5-FU could induce the expression of p53, which then upregulated miR-26a and downregulated Mcl1 levels, and finally promoted the apoptosis of HCC cells through a mitochondrial pathway.

Conclusion

These findings highlight the important and related molecular mechanism of miR-26a in the regulation of apoptosis and implicate the potential application of combination of IFN-α1b and 5-FU in HCC treatment.

MircroRNA-139 sensitizes ovarian cancer cell to cisplatin-based chemotherapy through regulation of ATP7A/B

PURPOSE

Ovarian cancer remains a most malignant female cancer nowadays. The acquisition of chemoresistance to common-used cisplatin-based chemotherapy results in a decreased overall patient survival. The present study is aimed to investigate the role and mechanism by which miR-139/ ATPases7A/B axis modulates the chemoresistance of ovarian cancer to cisplatin-based chemotherapy.

METHODS

The expression of miR-139 in cisplatin-sensitive (n = 23) and cisplatin-resistant (n = 14) ovarian cancer tissues and cell lines (CAOV-3 and SNU119) was determined using real-time PCR assays; its effect on ovarian cancer cell chemoresistance to different concentrations of cisplatin was then assessed by measuring the cell viability using MTT assays. Next, miR-139 binding to the 3'UTR of ATP7A/B was confirmed using luciferase reporter gene assays. Finally, the combined effect of miR-139 and ATP7A/B on the chemoresistance of ovarian cancer cell was assessed.

RESULTS

miR-139 expression was down-regulated in cisplatin-resistant ovarian cancer tissues (**P < 0.01) and reduced by cisplatin treatment in ovarian cell lines (*P < 0.05, **P < 0.01); miR-139 could enhance cisplatin-induced suppression on ovarian cancer cell viability, shown as reduced lC50 values; ATP7A and ATP7B protein levesincreased approximately 2 ~ fold-changein cisplatin-resistant cell lines. MiR-139 directly bound to the 3'UTR of ATP7A/B, respectively; miR-139 inhibition increased lC50 values whereas ATP7A/B knockdown reduced lC50 values of CAOV-3 and SNU119 cell lines under cisplatin treatment; the effect of miR-139 inhibition could be partially attenuated by ATP7A/B knockdown.

CONCLUSIONS

MiR-139/ATP7A/B axis can be a reliable biomarker for ovarian cancer diagnosis, and may affect the chemoresistance of ovarian cancer to cisplatin-based chemotherapy; rescuing miR-139 expression thus to inhibit ATP7A/B might contribute to dealing with the chemoresistance of ovarian cancer.

miR-223-3p Inhibits Human Osteosarcoma Metastasis and Progression by Directly Targeting CDH6

Cadherin-6 (CDH6) is aberrantly expressed in cancer and closely associated with tumor progression. However, the functions of CDH6 in human osteosarcoma and the molecular mechanisms underlying CDH6 in osteosarcoma oncogenesis remain poorly understood. In this work, we assessed the role of CDH6 in human osteosarcoma and identified that the expression of CDH6 was closely related with the overall survival and poor prognosis of osteosarcoma patients. MicroRNAs (miRNAs) have been implicated as important epigenetic regulators during the progression of osteosarcoma. Using dual-luciferase reporter assays, we showed that miR-223-3p suppresses CDH6 expression by directly binding to the 3' UTR of CDH6. miR-223-3p overexpression significantly inhibited cell invasion, migration, growth, and proliferation by suppressing the CDH6 expression in vivo and in vitro. Besides, CDH6 overexpression in the miR-223-3p-transfected osteosarcoma cells effectively rescued the inhibition of cell invasion, migration, growth, and proliferation mediated by miR-223-3p. Additionally, Kaplan-Meier analysis suggests that the expression of miR-223-3p predicts favorable clinical outcomes for osteosarcoma patients. Moreover, the expression of miR-223-3p was downregulated in osteosarcoma patients and was negatively associated with the expression of CDH6. Collectively, these data highlight that miR-223-3p/CDH6 axis is an important novel pleiotropic regulator and could early predict the metastatic potential in human osteosarcoma treatments.

Identification of microRNA 885-5p as a novel regulator of tumor metastasis by targeting CPEB2 in colorectal cancer

Colorectal cancer is the third most common cancer in the world and liver is the most frequent site of distant metastasis with poor prognosis. The aim of this study is to investigate microRNAs leading to liver metastasis. We applied microarray analysis and quantitative PCR to identify and validate dysregulated miRNAs in liver metastases when compared to primary CRCs. Functional significance and the underlying molecular mechanism of selected miRNA was demonstrated by a series of in vitro and in vivo assays. Our microarray analysis and subsequent quantitative PCR validation revealed that miR-885-5p was strongly up-regulated in liver metastases and in CRC cell-lines derived from distant metastases. Overexpression of miR-885-5p significantly induced cell migration, cell invasion, formation of stress fibre in vitro and development of liver and lung metastases in vivo. MiR-885-5p induced metastatic potential of CRC by repressing cytoplasmic polyadenylation element binding protein 2 transcription through directly binding to two binding sites on its 3′ untranslated region, and consequently led to up-regulation of TWIST1 and hence epithelial-mesenchymal transition. Our findings demonstrated the overexpression of miR-885-5p in liver metastasis and its roles in inducing CRC metastasis, potentiating development of miR-885-5p inhibitor to treat advanced CRC in the future.

MicroRNA-342 Prohibits Proliferation and Invasion of Melanoma Cells by Directly Targeting Zinc-Finger E-Box-Binding Homeobox 1

As documented in numerous studies, microRNAs (miRNAs) play key roles in various biological processes associated with melanoma occurrence and development. In this study, we found that miRNA-342 (miR-342) was significantly downregulated in melanoma tissues and cell lines. Additionally, the ectopic expression of miR-342 prohibited the cell proliferation and invasion of melanoma. Moreover, zinc-finger E-box-binding homeobox 1 (ZEB1) was identified as a direct target gene of miR-342 in melanoma. Similar with the results induced by miR-342 overexpression, ZEB1 knockdown attenuated cell proliferation and invasion in melanoma. Furthermore, the restoration of ZEB1 expression reversed the suppressive effects of miR-342 on the proliferation and invasion of melanoma cells. These findings suggest that miR-342 may play tumor-suppressing roles in melanoma, at least partially, by directly inhibiting ZEB1 expression. Therefore, miR-342 may be developed as a potential candidate for the treatment of patients with this aggressive type of cancer.

MicroRNA-33a-3p suppresses cell migration and invasion by directly targeting PBX3 in human hepatocellular carcinoma

MicroRNAs (miRNAs) have been shown to function as either oncogenes or tumor suppressors by negatively regulating target genes involved in tumor initiation and progression. In this study, we demonstrated that down-regulation of miR-33a-3p in human primary hepatocellular cancer (HCC) specimens was significantly associated with metastases and poor survival. Over-expression of miR-33a-3p in HepG2 cells remarkably suppressed not only cell growth, migration and invasion, but also tumor growth and metastases in the chick embryo chorioallantoic membrane (CAM) assay, and down-regulated Pre-B-Cell Leukemia Homeobox 3 (PBX3) expression. Conversely, inhibition of miR-33a-3p in Bel-7402 cells resulted in increased of cell growth, spreading and invasion. Furthermore, rescue experiments by over-expression PBX3 completely eliminated the inhibitory effects of miR-33a-3p on tumor growth and metastasis, both in vitro and in vivo. The luciferase assay showed that 3′-untranslated regions (3′-UTRs) of PBX3 were inhibited significantly by miR-33a-3p, while mutations in the miR-33a-3p pairing residues rescued the luciferase expression. Taken together, our findings suggest that miR-33a-3p suppressed the malignant phenotype while also inhibiting PBX3 expression in hepatocellular cancer, implying that miR-33a-3p may be a promising biomarkers and therapy target for HCC intervention.

Predictive microRNAs for lymph node metastasis in endoscopically resectable submucosal colorectal cancer

Accurate prediction of regional lymph node metastasis (LNM) in endoscopically resected T1-stage colorectal cancers (CRCs) can reduce unnecessary surgeries. To identify miRNA markers that can predict LNM in T1-stage CRCs, the study was conducted in two phases; (I) miRNA classifier construction by miRNA-array and quantitative reverse transcription PCR (qRT-PCR) using 36 T1-stage CRC samples; (II) miRNA classifier validation in an independent set of 20 T1-stage CRC samples. The expression of potential downstream target genes of miRNAs was assessed by immunohistochemistry. In the discovery analysis by miRNA microarray, expression of 66 miRNAs were significantly different between LNM-positive and negative CRCs. After qRT-PCR validation, 11 miRNAs were consistently significant in the combined classifier construction set. Among them, miR-342-3p was the most significant one (P=4.3×10-4). Through logistic regression analysis, we developed a three-miRNA classifier (miR-342-3p, miR-361-3p, and miR-3621) for predicting LNM in T1-stage CRCs, yielding the area under the curve of 0.947 (94% sensitivity, 85% specificity and 89% accuracy). The discriminative ability of this system was consistently reliable in the independent validation set (83% sensitivity, 64% specificity and 70% of accuracy). Of the potential downstream targets of the three-miRNAs, expressions of E2F1, RAP2B, and AKT1 were significantly associated with LNM. In conclusion, this classifier can predict LNM more accurately than conventional pathologic criteria and our study results may be helpful to avoid unnecessary bowel surgery after endoscopic resection in early CRC.

Mechanisms of Drug Resistance in Cancer: The Role of Extracellular Vesicles

Drug resistance remains a major barrier to the successful treatment of cancer. The mechanisms by which therapeutic resistance arises are multifactorial. Recent evidence has shown that extracellular vesicles (EVs) play a role in mediating drug resistance. EVs are small vesicles carrying a variety of macromolecular cargo released by cells into the extracellular space and can be taken up into recipient cells, resulting in transfer of cellular material. EVs can mediate drug resistance by several mechanisms. They can serve as a pathway for sequestration of cytotoxic drugs, reducing the effective concentration at target sites. They can act as decoys carrying membrane proteins and capturing monoclonal antibodies intended to target receptors at the cell surface. EVs from resistant tumor cells can deliver mRNA, miRNA, long noncoding RNA, and protein inducing resistance in sensitive cells. This provides a new model for how resistance that arises can then spread through a heterogeneous tumor. EVs also mediate cross-talk between cancer cells and stromal cells in the tumor microenvironment, leading to tumor progression and acquisition of therapeutic resistance. In this review, we will describe what is known about how EVs can induce drug resistance, and discuss the ways in which EVs could be used as therapeutic targets or diagnostic markers for managing cancer treatment. While further characterization of the vesiculome and the mechanisms of EV function are still required, EVs offer an exciting opportunity in the fight against cancer.

miR-1908 as a novel prognosis marker of glioma via promoting malignant phenotype and modulating SPRY4/RAF1 axis

MicroRNAs (miRNAs) are reported to be involved in the development of glioma. However, study on miRNAs in glioma is limited. The present study aimed to identify miRNAs which can act as potential novel prognostic markers for glioma and analyze its possible mechanism. We show that miR-1908 correlates with shorter survival time of glioma patients via promoting cell proliferation, invasion, anti-apoptosis and regulating SPRY4/RAF1 axis. Analysis of GEO and TCGA database found that miR-1908 was significantly upregulated in glioma tissues, and strongly associated with shorter survival time of glioma patients. Further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that miR-1908 is mainly involved in regulating cell proliferation, invasion and apoptosis. To further confirm the above results, in vitro, glioma U251 cells were transfected with miR-1908 mimics or inhibitor, and upregulated miR-1908 promoted U251 cell proliferation, and enhanced the ability of invasion by Transwell assay. In addition, upregulated miR-1908 also enhanced anti-apoptosis ability of U251 cells through decreasing pro-apoptosis protein Bax expression. Since miRNAs regulate numerous biological processes by targeting broad set of messenger RNAs, validated target genes of miR-1908 in glioma were analyzed by TargetScan and miRTarBase databases. Among them SPRY4 was significantly decreased in glioma tissues and associated with short survival time, which was selected as the key target gene of miR-1908. Moreover, protein-protein interaction (PPI) showed that SPRY4 could interacted with pro-oncogene RAF1 and negatively correlated with RAF1 expression. Consistent with above analysis, in vitro, western blot analysis identified that miR-1908 upregulated significantly decreased SPRY4 expression and increased RAF1 expression. Hence, miR-1908 was correlated with poor prognosis of glioma via promoting cell proliferation, invasion, anti-apoptosis and regulating SPRF4/RAF1 axis. Our results elucidated the tumor promoting role of miR-1908 and established miR-1908 as a potential novel prognostic marker for glioma.

miR-206/133b Cluster: A Weapon against Lung Cancer?

Lung cancer is a deadly disease that ends numerous lives around the world. MicroRNAs (miRNAs) are a group of non-coding RNAs involved in a variety of biological processes, such as cell growth, organ development, and tumorigenesis. The miR-206/133b cluster is located on the human chromosome 6p12.2, which is essential for growth and rebuilding of skeletal muscle. The miR-206/133b cluster has been verified to be dysregulated and plays a crucial role in lung cancer. miR-206 and miR-133b participate in lung tumor cell apoptosis, proliferation, migration, invasion, angiogenesis, drug resistance, and cancer treatment. The mechanisms are sophisticated, involving various target genes and molecular pathways, such as MET, EGFR, and the STAT3/HIF-1α/VEGF signal pathway. Hence, in this review, we summarize the role and potential mechanisms of the miR-206/133b cluster in lung cancer.

MicroRNA-320 suppresses cervical cancer cell viability, migration and invasion via directly targeting FOXM1

Cervical cancer is one of the most common types of gynecological cancer worldwide. MicroRNA-320 (miR-320) has been reported to be downregulated in a number of types of human cancer. However, the expression level and functions of miR-320 in cervical cancer remain unknown. In the present study, miR-320 was identified to be markedly downregulated in cervical cancer tissues and cell lines. For the functional studies, miR-320 mimic or miR-320 inhibitor was introduced into cervical cancer cell lines. The effects of miR-320 on cervical cancer cell viability, migration and invasion were evaluated using MTT, migration and invasion assays, respectively. The results of the present study identified that overexpression of miR-320 suppressed the viability, migration and invasion of cervical cancer cells. In contrast, underexpression of miR-320 improved the viability, migration and invasion of cervical cancer cells. Bioinformatics analysis, dual-luciferase reporter assay and western blot analysis were adopted to investigate the underlying molecular mechanism of the suppressive functions of miR-320 in cervical cancer. The results of the present study demonstrated that miR-320 negatively regulated forkhead box M1 (FOXM1) expression by directly targeting the 3' untranslated region of FOXM1. Furthermore, the functions of FOXM1 short interfering RNA were similar to those induced by miR-320 in cervical cancer, identifying FOXM1 as a functional target of miR-320 in cervical cancer. The results of the present study indicated that miR-320 acted as a tumor suppressor in the viability, migration and invasion of cervical cancer through directly targeting FOXM1, suggesting that miR-320 may be a target for the therapeutic treatment of cervical cancer.

miR-17-92基因簇在肿瘤发生发展中作用的研究进展

肿瘤是威胁全世界人类健康和影响社会经济的重要因素. 近年来, 随着经济的发展, 肿瘤的发病率呈明显上升趋势, 但是其病因尚未完全阐明. 越来越多的证据显示肿瘤的发生和遗传因素有关, 随着病理生理学和遗传学的发展, 许多学者认为生物标志物可以预测癌症甚至指导临床治疗. 微小RNA(microRNA, miRNA)是非编码小分子RNA, 在发育、生理、病理过程以及肿瘤发生等环节中起着重要的调节作用. miR-17-92基因簇是研究较为深入、最有特点的miRNA, 被认为是原癌基因miRNA的代表, 在多种肿瘤的发生发展中起着至关重要的作用. 本文就miR-17-92基因簇在肿瘤发生发展中的作用及功能进行综述.

miR-338-3p inhibits the invasion of renal cell carcinoma by downregulation of ALK5

Background

The current study aims to elucidate the role of miRNA-338-3p (miR-338-3p) in the invasion of renal cell carcinoma (RCC).

Methods

Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to detect the expression of miR-338-3p in human RCC cell lines with high metastatic potential (Caki-1) and low metastatic potential (786-O), respectively. The Caki-1 and 786-O cells were transfected with miR-338-3p mimic or inhibitor. Wound healing assay, Transwell assay and western blotting were performed to analyze the invasive ability and expression of activin receptor-like kinase 5 (ALK5) in the RCC cell lines. During the 36-month follow-up, we detected the expressions of miR-338-3p and ALK5 in 22 RCC cases with metastasis and 60 cases achieving a remission.

Results

miR-339-3p was significantly downregulated in the Caki-1 cells as compared with the 786-O cells. The transfection with miR-338-3p inhibitor caused an increased invasive ability of both two cell lines. However, the transfection with miR-338-3p mimic caused a reduction of the invasiveness. In RCC cells, the expression of ALK5 was negatively correlated to miR-338-3p. Upregulation of ALK5 partially counteracted the miR-338-3p-induced invasiveness of RCC cells. We subsequently found the negative correlations between miR-338-3p and metastasis/ALK5 expression could be also observed in human RCC tissues.

Conclusion

Taken together, these results indicate that miR-338-3p acts as a novel tumor suppressor to inhibit the invasion of RCC by regulating ALK5 expression.

MicroRNA‑302a suppresses cell proliferation, migration and invasion in osteosarcoma by targeting ADAM9

Osteosarcoma (OS) is the most frequent malignant primary bone tumor arising from primitive bone‑forming mesenchymal cells in children and adolescents. The dysregulation of microRNAs (miRNAs) has been reported in OS, and these aberrantly expressed miRNAs are involved in the initiation and progression of OS. The aim of the present study was to investigate the expression and functions of miRNA‑302a (miR‑302a) in OS and its underlying mechanism. It was found that the expression of miR‑302a was reduced in OS tissues and cell lines. The low expression of miR‑302a was significantly correlated with tumor‑node‑metastasis stage and metastasis. The ectopic overexpression of miR‑302a inhibited the proliferation, migration and invasion of OS cells. Bioinformatics analysis showed that a disintegrin and metalloproteinase 9 (ADAM9) was a potential target gene of miR‑302a. Subsequently, reverse transcription‑quantitative polymerase chain reaction and western blot analyses revealed that miR‑302a regulated the expression of ADAM9 at the post‑transcriptional level in OS cells. In addition, a luciferase reporter assay demonstrated that miR‑302a directly targeted the 3'untranslated region of ADAM9. In clinical OS tissues, the mRNA expression of ADAM9 was upregulated and inversely correlated with the expression of miR‑302a. In addition, the effects of ADAM9 knockdown on cell proliferation, migration and invasion were similar to those induced by the overexpression of miR‑302a in OS cells. These findings suggested that miR‑302a inhibited OS cell growth and metastasis by targeting ADAM9. miR‑302a may serve as a potential therapeutic target for patients with OS.

MicroRNA-497 upregulation inhibits cell invasion and metastasis in T24 and BIU-87 bladder cancer cells

Previous studies have reported the crucial role of microRNAs (miRNAs) in the biology and tumorigenesis of various types of cancer, including bladder cancer. The present study aimed to investigate the importance of miRNA (miR)‑497 on the pathogenesis of bladder cancer. A total of 50 patients diagnosed with bladder cancer were enrolled in the current study. The expression levels of miR‑497 in the cancerous and the adjacent noncancerous tissues were detected using reverse transcription‑quantitative polymerase chain reaction. The association between miR‑497 expression and various parameters, including age, tumor‑node‑metastasis (TNM) stage and pathological classification was determined. An miR‑497‑overexpressing vector was transfected into the T24 and BIU‑87 bladder cancer cell lines in order to determine the effect of miR‑497 expression on cell migration and invasion using Transwell assays. Additionally, the cell migration and invasion‑associated protein expression levels were also analyzed using western blotting. The findings of the present study revealed that miR‑497 was expressed at low levels in the cancer bladder tissue compared with the adjacent noncancerous tissue, and its expression was associated with the pathological classification, TNM stage and metastasis. Additionally, miR‑497 overexpression significantly reduced the number of migrated and invasive T24 and BIU‑87 cells. The mRNA and protein expression levels of E‑cadherin were increased, whereas levels of vimentin and α‑smooth muscle actin were reduced following miR‑497 overexpression. The present study revealed that miR‑497 overexpression may be a suppressor of the metastasis of bladder cancer, and may have an important role in the diagnosis of bladder cancer.

MicroRNA-362 is downregulated in cervical cancer and inhibits cell proliferation, migration and invasion by directly targeting SIX1

Cervical cancer is the second most common type of cancer in women accounting for 12% of all human cancers in the world. Mounting evidence demonstrates that microRNAs play important roles in the carcinogenesis and progression of cervical cancer. The aim of this study was to investigate the expression, roles and molecular mechanism of microRNA-362 (miR-362) in cervical cancer. According to the results, we found that expression level of miR-362 was significantly reduced in cervical cancer tissues and cell lines. Low miR-362 expression was correlated with FIGO stage, lymph node metastasis and vascular invasion in cervical cancer. Functional assays showed that restoration of miR-362 repressed cell proliferation, migration and invasion in cervical cancer. We also provided direct evidence that sineoculis homeobox homolog 1 (SIX1) was a direct target of miR-362 in cervical cancer, which was confirmed by bioinformatics analysis, luciferase reporter assay, qRT-PCR and western blot analysis. SIX1 was upregulated in cervical cancer and inversely correlated with miR‑362 expression in cervical cancer. In addition, SIX1 knockdown could simulate the roles of miR-362 overexpression on cell proliferation, migration and invasion of cervical cancer. Moreover, rescue experiments indicated that restoration of SIX1 was sufficient to abolish proliferation, migration and invasion induced by miR-362 overexpression in cervical cancer cells. The newly identified miR-362/SIX1 pathway provides insight into cervical cancer progression, and may represent a novel therapeutic target.

miR-544a Promotes Breast Cancer Cell Migration and Invasion Reducing Cadherin 1 Expression

Accumulating evidence has reported the significant role of miRNAs in the underlying biology of tumors, including breast cancer. The purpose for this study was to investigate the potential effects of miR-544a in breast cancer migration and invasion. The human normal breast Hs578Bst cells and the human breast cancer MCF-7 and MDA-MB-231 cells were used to analyze the expression of miR-544a by RT-PCR. The effects of miR-544a on the two kinds of breast cancer cell migration and invasion were analyzed using the Matrigel and Transwell assay, respectively. miR-544a expression on the cell metastasis-related protein expression was also analyzed using Western blotting. Compared to the normal Hs578Bst cells, miR-544a was significantly downregulated in MCF-7 cells but was upregulated in MDA-MB-231 cells (p < 0.01). The overexpressed miR-544a significantly promotes the migrated and invaded MCF-7 cells (p < 0.05), which was opposite to that in MCA-MB-231 cells (p < 0.05). Moreover, the cadherin 1 (CDH1) expression was negatively correlated to miR-544a expression in the two kinds of cells. Our study suggested that the overexpressed miR-544a may be a promoter for breast cancer migration and invasion by targeting CDH1.

MicroRNA-320 regulates the radiosensitivity of cervical cancer cells C33AR by targeting β-catenin

Cervical cancer is the second most common malignancy in women worldwide and always has recurrence owing to radioresistance. MicroRNA (miRNA or miR) has been identified to relate to the sensitivity of cancer radiotherapy. Here, we investigated the potential of miRNA-320 as a biomarker for radiosensitivity by targeting β-catenin in cervical cancer. A radioresistant cervical cancer cell line, C33AR, was established, and the radioresistance of C33AR cells was confirmed by a colony-formation assay. The expression of miRNA-320 was detected by reverse transcription-quantitative polymerase chain reaction, and compared between C33A and C33AR. β-catenin, the target of miRNA-320, was determined at the protein level by western blotting after transfecting the inhibitor of miRNA-320. The expression of miRNA-320 was markedly decreased in C33AR cells, which appeared to be more radioresistant, compared with its parental cell line C33A. Target prediction suggested that miRNA-320 negatively regulated the expression of β-catenin. Knockdown of β-catenin increased C33AR radiosensitivity, which revealed that the inhibition of β-catenin could rescue the miRNA-320-mediated cell radioresistance. On the other hand, overexpressing miRNA-320 increased C33AR radiosensitivity. In conclusion, miRNA-320 regulated the radiosensitivity of C33AR cells by targeting β-catenin. This finding provides evidence that miRNA-320 may be a potential biomarker of radiosensitivity in cervical cancer.