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Objective • It has been well documented that microRNAs (miRNAs) play essential roles in cancer initiation and development. In this study, we aimed to provide a better understanding of the mechanism of cell proliferation in glioblastoma (GBM). Methods • Levels of miR-601 expression were detected in GBM tissues and cells. The effects of miR-601 dysregulation on GBM cell proliferation by mean transit time (brain tissue blood flow) (MTT) assays, colony formation, anchorage-independent growth assay, bromodeoxyuridine (BrdU) labeling and immunofluorescence assay. Bioinformatics analysis, luciferase reporter system and Western blot assays were used to predict and confirm the target gene miR-601. Results • MiR-601 levels were identified as significantly up-regulated in GBM primary tumors and cell lines. Ectopic expression of miR-601 suppressed cell proliferation of GBM. Moreover, miR-601 showed its function by suppressing potential target TINP1 and TINP1 suppression reversed the effects of miR-601-in in U87MG GBM cells. Conclusion • Taken together, our results indicate that miR-601 promotes proliferation of GBM via inhibition of TINP1. [ABSTRACT FROM AUTHOR]

Purpose: Prostate cancer chemoresistance is a major contributor to the poor survival of patients. MicroRNAs (miRNAs) play an important role in regulating cancer resistance. Here we aim to explore the role and mechanism of miR-199a in regulating prostate cancer resistance. Methods: MiR-199a expressions in human prostate cancer tissues and cell lines were investigated with real-time PCR (RTPCR). MiR-199a was ectopically overexpressed in PC3 cells, and resistance to paclitaxel (PTX) was evaluated consequently. The interaction between miR-199a and the oncogene Yamaguchi sarcoma viral homolog 1 (YES1) was assessed after miR-199a overexpression. YES1 was ectopically overexpressed, followed by evaluation of PTX resistance. The efficacy of miR-199a as a therapeutic agent was also investigated in vivo. Results: Downregulation of miR-199a was characteristic of prostate cancer, particularly recurrent cancers. MiR-199a was suppressed in PTX-resistant cell line. Overexpression of miR-199a inhibited PTX resistance. YES1 was a target of miR-199a, and overexpression of YES1 reversed the effect of miR-199a in suppressing PTX resistance. In vivo, miR-199a increased tumor PTX sensitivity. Conclusions: The downregulation of miR-199a contributes to PTX resistance in prostate cancer. YES1 mediates the regulation of miR-199a in prostate cancer PTX resistance. This miR-199a replacement therapy has potential to overcome PTX resistance. [ABSTRACT FROM AUTHOR]

Background: Cisplatin-based chemotherapy is frequently used to treat advanced gastric cancer (GC). However, the resistance often occurs with the mechanisms being not well understood. Recently, emerging evidence indicates that tumor-associated macrophages (TAMs) play an important role in chemoresistance of cancer. As the important mediators in intercellular communications, exosomes secreted by host cells mediate the exchange of genetic materials and proteins to be involved in tumor aggressiveness. The aim of the study was to investigate whether exosomes derived from TAMs mediate cisplatin resistance in gastric cancer. Methods: M2 polarized macrophages were obtained from mouse bone marrow or human PBMCs stimulated with IL-4 and IL-13. Exosomes isolated from M2 macrophages culture medium were characterized, and miRNA expression profiles of M2 derived exosomes (M2-exos) were analyzed using miRNA microarray. In vitro cell coculture was further conducted to investigate M2-exos mediated crosstalk between TAMs and tumor cells. Moreover, the in vivo experiments were performed using a subcutaneous transplantation tumor model in athymic nude mice. Results: In this study, we showed that M2 polarized macrophages promoted cisplatin (DDP) resistance in gastric cancer cells and exosomes derived from M2 macrophages (M2-exos) are involved in mediating the resistance to DDP. Using miRNA profiles assay, we identify significantly higher levels of microRNA-21 (miR21) isomiRNAs in exosomes and cell lysate isolated from M2 polarized macrophage. Functional studies revealed that exosomal miR-21 can be directly transferred from macrophages to the gastric cancer cells, where it suppresses cell apoptosis and enhances activation of PI3K/AKT signaling pathway by down-regulation of PTEN. Conclusions: Our findings suggest that exosomal transfer of tumor-associated macrophages derived miR-21 confer DDP resistance in gastric cancer, and targeting exosome communication may be a promising new therapeutic strategy for gastric cancer patients. [ABSTRACT FROM AUTHOR]

Purpose: Circular RNAs (circRNAs) participate in chemo-resistance among different cancers, containing breast cancer (BC). Herein, this project aimed to investigate the role of circ_0011385 on cisplatin (DDP) resistance in BC cells. Methods: circ_0011385 and microRNA (miR)-615-5p content in DDP-resistant BC cells and their parent cells (MCF-7) was calculated by RT-qPCR. CCK-8 assessed inhibition rate, and further to calculate half inhibitory concentration (IC50). Clone formation and flow cytometry experiments detected clone numbers and apoptosis rate. Dual-luciferase reporter system validated targeting between circ_0011385 and miR-615-5p. Results: circ_0011385 was upregulated, whereas miR-615-5p was decreased in MCF-7/DDP cells. Silencing circ_0011385 or miR-615-5p overexpression enhanced BC cell sensitivity to DDP, repress proliferation, and expedite apoptosis rate. Circ_0011385 directly targeted miR-615-5p. CONCLUSION: Silencing circ_0011385 increases DDP sensitivity by targeting and up-regulating miR-615-5p expression in MCF-7/DDP. [ABSTRACT FROM AUTHOR]

The aberrant proliferation of nucleus pulposus (NP) cells has been reported to be implicated in the pathogenesis of intervertebral disc degeneration (IDD). Previous studies have demonstrated that microRNAs (miRNAs), which are a group of small noncoding RNAs, are critical regulators of cell proliferation in various pathologies. However, the role of miRNA‑96 (miR‑96) in the proliferation of NP cells remains to be determined. In the present study, reverse transcription‑quantitative polymerase chain reaction was used to investigate the expression of miR‑96 in NP tissues from patients with IDD and healthy tissues from patients with traumatic lumbar fracture as the control. A dual‑luciferase reporter assay was used to investigate whether AT‑rich interaction domain 2 (ARID2) may be a direct target gene for miR‑96. Furthermore, isolated NP cells from patients with IDD were transfected with miR‑96 mimics and ARID2‑targeting small interfering RNAs; cell proliferation, and the protein expression of Akt, phosphorylated Akt and ARID2 were examined, whereas the effects of an Akt inhibitor on NP cell proliferation were also evaluated. The present results demonstrated that miR‑96 expression was significantly upregulated in IDD samples, and the level of miR‑96 expression was positively associated with disc degeneration grade, which was evaluated by a modified Pfirrmann grading system. In addition, the current study identified ARID2 as a direct gene target of miR‑96. Furthermore, it was demonstrated that ARID2 mRNA expression was inversely correlated with the expression of miR‑96 in NP tissues. In addition, miR‑96 overexpression promoted NP cell proliferation and induced Akt phosphorylation, which led to increased cyclin D1 translation. Notably, overexpression of ARID2 or treatment with an Akt inhibitor decreased the effect of miR‑96 on NP cell proliferation. In conclusion, the results of the present study indicate that miR‑96 may promote the proliferation of human degenerated NP cells by targeting ARID2 via activation of the Akt pathway, and potentially serves as a therapeutic target for IDD. [ABSTRACT FROM AUTHOR]

Mechanical stimuli are required for the maintenance of skeletal integrity and bone mass. An increasing amount of evidence indicates that multiple regulators (e.g., hormone, cytoskeleton proteins and signaling pathways) are involved in the mechanical stimuli modulating the activities of osteogenic cells and the process of bone formation. Significantly, recent studies have showed that several microRNAs (miRNAs) were sensitive to various mechanical stimuli and played a crucial role in osteogenic differentiation and bone formation. However, the functional roles and further mechanisms of mechanosensitive miRNAs in bone formation are not yet completely understood. This review highlights the roles of mechanosensitive miRNAs in osteogenic differentiation and bone formation and underlines their potential therapeutic application for bone loss induced by the altering of mechanical stimuli. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRs) have important roles in the parthenogenesis of malignancies. While it has been suggested that deregulation of miR-101 is involved in bladder cancer, the underlying mechanisms have remained largely elusive. The present study aimed to investigate the roles of miR-101 in the regulation of bladder cancer cell proliferation and invasion. Reverse-transcription quantitative polymerase chain reaction analysis revealed that the expression of miR-101 was significantly reduced in the HT-1376, BIU87, T24 and 5637 several human bladder cancer cell lines compared to that in the SV-HUC-1 normal bladder epithelial cell line. Furthermore, a Targetscan search and a luciferase assay were used to identify c-FOS as a novel target of miR-101, and western blot analysis indicated that the protein expression of c-FOS was shown to be negatively regulated by miR-101 in bladder cancer T24 cells; however, c-FOS mRNA expression was not affected. In addition, plasmid-mediated overexpression of miR-101 and small hairpin RNA-mediated inhibition of c-FOS significantly inhibited the proliferation and invasive capacity of T24 cells, as indicated by an MTT and a Transwell assay, respectively. However, plasmid-mediated overexpression of c-FOS reversed the inhibitory effects of miR-101 overexpression on T24-cell proliferation and invasion. In conclusion, the present study demonstrated that miR-101 inhibits the proliferation and invasion of bladder cancer cells, at least partly via targeting c-FOS, suggesting that miR-101/c-FOS signaling may represent a potential therapeutic target for bladder cancer. [ABSTRACT FROM AUTHOR]

Background: MicroRNAs (miR, miRNAs) play pivotal roles in numerous physiological and pathophysiological contexts. We investigated whether miR-362-5p act as an oncogene in chronic myeloid leukaemia (CML) and aimed to understand its potential underlying mechanisms. Methods: We compared the miR-362-5p expression levels between CML and non-CML cell lines, and between fresh blood samples from CML patients and normal healthy controls using quantitative real-time PCR (qPCR). Cell counting kit-8 (CCK-8) and Annexin V-FITCH/PI analyses were used to measure the effects of miR-362-5p on proliferation and apoptosis, and Transwell assays were used to evaluate migration and invasion. A xenograft model was used to examine in vivo tumourigenicity. The potential target of miR-362-5p was confirmed by a luciferase reporter assay, qPCR and western blotting. Involvement of the JNK1/2 and P38 pathways was investigated by western blotting. Results: miR-362-5p was up-regulated in CML cell lines and fresh blood samples from CML patients, and was associated with Growth arrest and DNA damage-inducible (GADD)45α down-regulation. Inhibition of miR-362-5p simultaneously repressed tumour growth and up-regulated GADD45α expression in a xenograft model. Consistently, the knockdown of GADD45α expression partially neutralized the effects of miR-362-5p inhibition. Furthermore study suggested that GADD45α mediated downstream the effects of miR-362-5p, which might indirectly regulates the activation of the JNK1/2 and P38 signalling pathways. Conclusion: miR-362-5p acts as an oncomiR that down-regulates GADD45α, which consequently activates the JNK1/2 and P38 signalling. This finding provides novel insights into CML leukaemogenesis and may help identify new diagnostic and therapeutic targets. [ABSTRACT FROM AUTHOR]

A body of evidence has indicated that microRNAs (miRNAs) may have significant roles in cancer. Aberrant expression of miRNAs has frequently been observed in various human malignancies, including osteosarcoma (OS). However, the roles of miRNAs in OS remain poorly understood. In the present study, high-throughput deep sequencing was performed to screen for deregulated miRNAs in OS. Screening identified 310 miRNAs which were significantly overexpressed and 41 miRNAs which were significantly downregulated (>2-fold) in OS samples, compared with adjacent non-tumor bone tissues. Among these miRNAs, miR-33a-5p was notably downregulated. TaqMan reverse transcription- polymerase chain reaction analysis further verified that miR-33a-5p expression was significantly reduced in a large cohort of human OS samples. Enhancing miR-33a-5p expression via transfection with miR-33a-5p precursor significantly inhibited OS cell growth, suggesting potential antitumor properties of miR-33a-5p. The results of the present study provide novel insights into the miRNAs involved in OS, and suggest that miR-33a-5p may function as a tumor suppressor in OS. Therefore, miR-33a-5p may be able to serve as a diagnostic and therapeutic target for OS treatment. [ABSTRACT FROM AUTHOR]

Ascl2, a basic helix-loop-helix transcription factor, is a downstream target of WNT signaling that controls the fate of intestinal cryptic stem cells and colon cancer progenitor cells. However, its involvement in colon cancer and downstream molecular events is largely undefined; in particular, the mechanism by which Ascl2 regulates the plasticity of epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) programs in colon cancer cells remains unknown. In this study, we systematically demonstrate that Ascl2 loss of function in colon cancer cells promotes MET by derepressing the expression of microRNA (miR)-200s (i.e. miR-200b, miR- 200a, miR-429, miR-200c, and miR-141) and further activating their expression through a transcriptional mechanism that involves direct binding to the most proximal E-box (E-box2) in the miR-200b-a-429 promoter. Activation of miR-200s due to Ascl2 deficiency led to the inhibition of ZEB1/2 expression and the alteration of epithelial and mesenchymal features. Transfection of miR-200b, miR-200a, and miR-429 inhibitors into Ascl2- deficient colon cancer cells promoted the epithelial-mesenchymal transition in a reversible manner. Transfection of miR-200a or miR-429 inhibitors into Ascl2-deficient colon cancer cells increased cellular proliferation and migration. Ascl2mRNAlevels and the miR-200a, miR-200b, miR-200c, miR-141, or miR- 429 levels in the colon cancerous samples were inversely correlated. These results provide the first evidence of a link between Ascl2 and miR-200s in the regulation of EMT-MET plasticity in colon cancer. [ABSTRACT FROM AUTHOR]

Background MicroRNAs are a class of endogenous single strand non-coding RNAs that are involved in many important physiological and pathological processes. The purpose of this study was to examine the expression levels of miR-497 in human breast cancer and its function in MDAMB- 231 breast cancer cells. Methods Quantitative polymerase chain reaction was used to measure the expression levels of miR- 497 in 40 breast cancer specimens and adjacent normal breast tissues. MTT assays, colony formation assays, wound healing assays, transwell assays and cell cycle assays were used to explore the potential function of miR-497 in MDA-MB-231 breast cancer cells. Dualluciferase reporter assays were performed to analyze the regulation of putative target of miR- 497, and western blot assays were used to validate the dual-luciferase results. Results The expression of miR-497 in breast cancer specimens was lower than adjacent normal tissues (P < 0.05). Overexpression of miR-497 inhibited cellular growth, suppressed cellular migration and invasion, and caused a G1 arrest. Dual-luciferase reporter assays showed that miR-497 binds the 3'-untranslated region (3'-UTR) of cyclin E1, suggesting that cyclin E1 is a direct target of miR-497. Western blot assays confirmed that overexpression of miR-497 reduced cyclin E1 protein levels. Conclusions MiR-497 may act as a tumor suppressor gene in breast cancer. Inhibited cellular growth, suppressed cellular migration and invasion, and G1 cell cycle arrest were observed upon overexpression of miR-497 in cells, possibly by targeting cyclin E1. These results indicate miR-497 could be considered a therapeutic target for the development of treatment for breast cancer. [ABSTRACT FROM AUTHOR]

Intermuscular adipose tissue is located between the muscle fiber bundles in skeletal muscles, and has similar metabolic features to visceral adipose tissue, which has been found to be related to a number of obesity-related diseases. Although various miRNAs are known to play crucial roles in adipose deposition and adipogenesis, the microRNA transcriptome of intermuscular adipose tissue has not, until now, been studied. Here, we sequenced the miRNA transcriptomes of porcine intermuscular adipose tissue by small RNA-sequencing and compared it to a representative subcutaneous adipose tissue. We found that the inflammation- and diabetes-related miRNAs were significantly enriched in the intermuscular rather than in the subcutaneous adipose tissue. A functional enrichment analysis of the genes predicted to be targeted by the enriched miRNAs also indicated that intermuscular adipose tissue was associated mainly with immune and inflammation responses. Our results suggest that the intermuscular adipose tissue should be recognized as a potential metabolic risk factor of obesity. [ABSTRACT FROM AUTHOR]

Breast milk is the primary source of nutrition for newborns, and is rich in immunological components. MicroRNAs (miRNAs) are present in various body fluids and are selectively packaged inside the exosomes, a type of membrane vesicles, secreted by most cell types. These exosomal miRNAs could be actively delivered into recipient cells, and could regulate target gene expression and recipient cell function. Here, we analyzed the lactation-related miRNA expression profiles in porcine milk exosomes across the entire lactation period (newborn to 28 days after birth) by a deep sequencing. We found that immune- related miRNAs are present and enriched in breast milk exosomes (p<10- 16, Χ² test) and are generally resistant to relatively harsh conditions. Notably, these exosomal miRNAs are present in higher numbers in the colostrums than in ature milk. It was higher in the serum of colostrum-only fed piglets compared with the mature milk-only fed piglets. These immune- related miRNA-loaded exosomes in breast milk may be transferred into the infant body via the digestive tract. These observations are a prelude to in-depth investigations of the essential roles of breast milk in the development of the infant's immune system. [ABSTRACT FROM AUTHOR]

Chondrogenic differentiation of mesenchymal stem cells (MSCs) is accurately regulated by essential transcription factors and signaling cascades. However, the precise mechanisms involved in this process still remain to be defined. MicroRNAs (miRNAs) regulate various biological processes by binding target mRNA to attenuate protein synthesis. To investigate the mechanisms for miRNAs-mediated regulation of chondrogenic differentiation, we identified that miR-145 was decreased during transforming growth factor beta 3 (TGF-&bgr;3)-induced chondrogenic differentiation of murine MSCs. Subsequently, dual-luciferase reporter gene assay data demonstrated that miR-145 targets a putative binding site in the 39-UTR of SRYrelated high mobility group-Box gene 9 (Sox9) gene, the key transcription factor for chondrogenesis. In addition, overexpression of miR-145 decreased expression of Sox9 only at protein levels and miR-145 inhibition significantly elevated Sox9 protein levels. Furthermore, over-expression of miR-145 decreased mRNA levels for three chondrogenic marker genes, type II collagen (Col2a1), aggrecan (Agc1), cartilage oligomeric matrix protein (COMP), type IX collagen (Col9a2) and type XI collagen (Col11a1) in C3H10T1/2 cells induced by TGF-b3, whereas anti-miR-145 inhibitor increased the expression of these chondrogenic marker genes. Thus, our studies demonstrated that miR-145 is a key negative regulator of chondrogenic differentiation by directly targeting Sox9 at early stage of chondrogenic differentiation. [ABSTRACT FROM AUTHOR]