circ-TFRC downregulation suppresses ovarian cancer progression via miR-615-3p/IGF2 axis regulation.

BACKGROUND: Ovarian cancer (OC) is a malignancy among female globally. Circular RNAs (circRNAs) are a family of circular endogenous RNAs generated from selective splicing, which take part in many traits. Former investigation suggested that circ-TFRC was abnormally expressed in breast cancer (BC). Further, the role of circ-TFRC to the progress of OC remains unclear. So, the aim of this study was to reveal the regulatory mechanism of circ-TFRC. METHODS: Our team made the luciferase reporter assay to validate circ-TFRC downstream target. Transwell migration assay, 5-ethynyl-20-deoxyuridine, and cell counting kit-8 were applied to investigate both proliferation and migration. In vivo tumorigenesis and metastasis assays were performed to investigate the circ-TFRC role in OC. RESULTS: The outputs elucidated that circ-TFRC expression incremented in OC cells and tissues. circ-TFRC downregulation inhibited OC cell proliferation as well as migration in in vivo and in vitro experiments. The luciferase results validated that miR-615-3p and IGF2 were circ-TFRC downstream targets. IGF2 overexpression or miR-615-3p inhibition reversed OC cell migration after circ-TFRC silencing. Also, IGF2 overexpression reversed OC cell migration and proliferation post miR-615-3p upregulation. CONCLUSION: Results demonstrate that circ-TFRC downregulation inhibits OC progression and metastasis via IGF2 expression regulation and miR-615-3psponging.

Circular RNA circ-MTHFD1L induces HR repair to promote gemcitabine resistance via the miR-615-3p/RPN6 axis in pancreatic ductal adenocarcinoma.

BACKGROUND: Chemoresistance of pancreatic cancer is the main reason for the poor treatment effect of pancreatic cancer patients. Exploring chemotherapy resistance-related genes has been a difficult and hot topic of oncology. Numerous studies implicate the key roles of circular RNAs (circRNAs) in the development of pancreatic cancer. However, the regulation of circRNAs in the process of pancreatic ductal adenocarcinoma (PDAC) chemotherapy resistance is not yet fully clear. METHODS: Based on the cross-analysis of the Gene Expression Omnibus (GEO) database and the data of our center, we explored a new molecule, hsa_circ_0078297 (circ-MTHFD1L), related to chemotherapy resistance. QRT-PCR was used to detect the expression of circRNAs, miRNAs, and mRNAs in human PDAC tissues and their matched normal tissues. The interaction between circ-MTHFD1L and miR-615-3p/RPN6 signal axis was confirmed by a series of experiments such as Dual-luciferase reporter assay, fluorescence in situ hybridization (FISH) RNA immunoprecipitation (RIP) assays. RESULTS: Circ-MTHFD1L was significantly increased in PDAC tissues and cells. And in PDAC patients, the higher the expression level of circ-MTHFD1L, the worse the prognosis. Mechanism analysis showed that circ-MTHFD1L, as an endogenous miR-615-3p sponge, upregulates the expression of RPN6, thereby promoting DNA damage repair and exerting its effect on enhancing gemcitabine chemotherapy resistance. More importantly, we also found that Silencing circ-MTHFD1L combined with olaparib can increase the sensitivity of pancreatic cancer to gemcitabine. CONCLUSION: Circ-MTHFD1L maintains PDAC gemcitabine resistance through the miR-615-3p/RPN6 signal axis. Circ-MTHFD1L may be a molecular marker for the effective treatment of PDAC.

HOTTIP downregulation reduces neuronal damage and microglial activation in Parkinson's disease cell and mouse models.

HOXA transcript at the distal tip (HOTTIP), a newly identified long noncoding RNA, has been shown to exhibit anti-inflammatory effects and inhibit oxygen-glucose deprivation-induced neuronal apoptosis. However, its role in Parkinson's disease (PD) remains unclear. 1-Methyl-4-phenylpyridium (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were used to establish PD models in SH-SY5Y and BV2 cells and in C57BL/6 male mice, respectively. In vitro, after HOTTIP knockdown by sh-HOTTIP transfection, HOTTIP and FOXO1 overexpression promoted SH-SY5Y apoptosis, BV2 microglial activation, proinflammatory cytokine expression, and nuclear factor kappa-B and NACHT, LRR and PYD domains-containing protein 3 inflammasome activation. Overexpression of miR-615-3p inhibited MPP+-induced neuronal apoptosis and microglial inflammation and ameliorated HOTTIP- and FOXO1-mediated nerve injury and inflammation. In vivo, HOTTIP knockdown alleviated motor dysfunction in PD mice and reduced neuronal apoptosis and microglial activation in the substantia nigra. These findings suggest that inhibition of HOTTIP mitigates neuronal apoptosis and microglial activation in PD models by modulating miR-615-3p/FOXO1. This study was approved by the Ethics Review Committee of the Affiliated Hospital of Qingdao University, China (approval No. UDX-2018-042) in June 2018.

Upregulation of LINC01503 promotes cervical cancer progression by targeting the miR-615-3p/CCND1 axis.

Mounting evidence indicates that long non-coding RNAs influence the progression of cervical cancer, but the precise function of LINC01503 in the pathogenesis of the disease remains unknown. Here, we found higher levels of LINC01503 in cervical cancer tissues. High LINC01503 expression was associated with enhanced progression of cervical cancer as indicated by advanced FIGO stage, increased metastasis of tumor cells to lymph nodes, and invasion into deeper cervical tissues. LINC01503 inhibition markedly suppressed the invasion and proliferative ability of tumor cells. Mechanistically, LINC01503 was demonstrated to negatively modulate the expression of miR-615-3p in cervical cancer. CCND1 was found to be a target of miR-615-3p. Rescue experiments indicated that LINC01503 inhibition suppressed the invasion and proliferative ability of the tumor cells, a phenomenon that was reversed following miR-615-3p inhibition or CCND1 overexpression. Collectively, these data indicate that LINC01503 enhances the progression of cervical cancer cells via interaction with miR-615-3p/CCND1 axis.

The Influence of rs1859168 Polymorphism on Serum Expression of HOTTIP and Its Target miR-615-3p in Egyptian Patients with Breast Cancer.

BACKGROUND: Polymorphisms of long noncoding RNAs are lately documented as hazardous factors for the development of numerous tumors. Furthermore, the evaluation of noncoding RNAs has emerged as a novel detector of breast cancer patients. We aimed to genotype the HOXA transcript at the distal tip (HOTTIP) rs1859168 and assess its relationship with the levels of the serum HOTTIP and its target miR-615-3p in patients with breast cancer (BC). METHODS: One hundred and fifty-one patients with BC, 139 patients with fibroadenoma (FA), and 143 healthy participants were incorporated into the current study. The genotyping of rs1859168 and the measurements of the HOTTIP and miR-615-3p levels were assessed using quantitative real-time PCR. RESULTS: We revealed a significant association between each of the CC genotypes, C allele, dominant and recessive models, and the increased risk of BC (p = 0.013, p < 0.001, p < 0.001, and p < 0.001, respectively) relative to the healthy controls. Similarly, the CC genotype, C allele, and recessive model were observed to be related to the increased incidence of BC with respect to FA (p < 0.001 for all). A significant upregulation of HOTTIP and a marked decrease of miR-615-3p were verified in patients with BC compared to each of the healthy individuals, patients with FA, and the non-BC group (healthy subjects + FA) (p < 0.001 for all). A significant negative correlation was demonstrated between the expression of HOTTIP and miR-615-3p in the serum of patients with BC. The HOTTIP expression was upregulated, while that of miR-615-3p was downregulated in patients with BC who carried the CC genotype with respect to those who carried the AA or AC genotypes (p < 0.05 for all). CONCLUSIONS: The genetic variants of rs1859168 are linked to an increased susceptibility to BC. Moreover, HOTTIP and miR-615-3p may be used as novel indicators and targets for the treatment of patients with BC.

Long noncoding RNA Nespas inhibits apoptosis of epileptiform hippocampal neurons by inhibiting the PI3K/Akt/mTOR pathway.

Epilepsy is one of the most common neurological diseases with spontaneous recurrent seizures. Long noncoding RNAs (lncRNAs) are crucial modulators in numerous diseases, including epilepsy. However, the functional role and potential mechanism of lncRNA Nespas in epilepsy remain unknown. Our study clarified that Nespas was underexpressed in epileptiform hippocampal tissues and neurons. Furthermore, Nespas promoted hippocampal neuron viability and proliferation, and inhibited hippocampal neuron apoptosis. Mechanistically, Nespas interacted with microRNA 615-3p (miR-615-3p) in epileptiform hippocampal neurons. 26S proteasome non-ATPase regulatory subunit 11 (Psmd11) was a downstream target of miR-615-3p, and Nespas elevated Psmd11 expression via competitively binding to miR-615-3p in epileptiform hippocampal neurons. In addition, rescue assays suggested that Nespas promoted hippocampal neuron viability and proliferation, and suppressed hippocampal neuron apoptosis by upregulation of Psmd11. Furthermore, Nespas suppressed the PI3K/Akt/mTOR pathway via upregulating Psmd11 in epileptiform hippocampal neurons. This report explored the function and regulatory mechanism of Nespas in epileptiform hippocampal neurons for the first time. Our findings revealed that Nespas suppressed the apoptosis of epileptiform hippocampal neurons by inhibiting the PI3K/Akt/mTOR pathway via upregulation of Psmd11 at a miR-615-3p dependent way, indicating that Nespas may offer a new direction for the treatment of epilepsy.

CircRNA ITCH increases bortezomib sensitivity through regulating the miR-615-3p/PRKCD axis in multiple myeloma.

AIMS: Bortezomib (BTZ) is described as the first-line agent for multiple myeloma (MM) chemotherapy, but the emergence of BTZ resistance usually results in the failure of chemotherapy in MM. Circular RNA (circRNA) itchy E3 ubiquitin protein ligase (circITCH) is a novel identified circRNA that plays a vital role in the development of human cancers. However, the role of circITCH in the development of BTZ resistance in MM remains elusive. MATERIALS AND METHODS: The expression of circITCH, miR-615-3p, and protein kinase C, delta (PRKCD) was detected with quantitative reverse transcription PCR and western blot. The effects of circITCH on the sensitivity of MM cells to BTZ were assessed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay, flow cytometry, and xenograft tumor assay. The interaction of circITCH, microRNA-615-3p, and PRKCD was explored using luciferase reporter assay and RNA immunoprecipitation assay. KEY FINDINGS: circITCH was downregulated in MM bone marrow specimens and cell lines, as well as BTZ-resistant MM cells. Reduced expression of circITCH was indicative of poor prognosis in MM patients. Upregulation of circITCH enhanced the sensitivity of BTZ-resistant MM cells to BTZ in vitro and in vivo. Furthermore, circITCH was identified as a sponge for miR-615-3p, and PRKCD is confirmed as a direct target of miR-615-3p. Besides, circITCH overexpression enhanced the sensitivity of MM cells to BTZ through miR-615-3p/PRKCD axis. SIGNIFICANCE: circITCH overexpression enhanced the sensitivity of MM cells to BTZ through miR-615-3p/PRKCD axis, providing a novel potential target for combating BTZ resistance in patients with MM.

The Potential Tumor Promotional Role of circVAPA in Retinoblastoma via Regulating miR-615-3p and SMARCE1.

BACKGROUND: Growing evidence reveals that circular RNAs (circRNAs) play roles in cancer development. However, the effects and possible mechanisms of circRNAs in retinoblastoma (RB) are far from clear. METHODS: circVAPA expression pattern was identified by RT-qPCR. circVAPA induced effects on RB cells were tested by CCK-8, clone forming, flow cytometry and transwell assays. Bioinformatics assay, rescue experiments and dual-luciferase tests were applied for mechanism exploration. Additionally, mouse models were established for in vivo assays. RESULTS: circVAPA was upregulated in human RB specimen and RB cell lines, and was correlated with poor outcomes of Rb patients. Knockdown of circVAPA could suppress the malignant phenotypes of RB. Mechanistic experiments demonstrated that miR-615-3p could reverse the circVAPA induced effects on RB cells, and the downstream oncogene SMARCE1 was positively regulated by circVAPA via miR-615-3p. Further, in vivo analysis confirmed the findings. CONCLUSION: In summary, circVAPA promoted RB proliferation and metastasis by sponging miR-615-3p, thereby upregulating SMARCE1. CircVAPA was a potential biomarker for Rb therapy.

Long noncoding RNA HOTTIP promotes the metastatic potential of ovarian cancer through the regulation of the miR-615-3p/SMARCE1 pathway.

Upregulation of lncRNA HOXA transcript at the distal tip (HOTTIP) plays important roles in cancer progression. Nevertheless, its functions in the growth and metastasis of ovarian carcinoma are unknown. In this study, we demonstrated overexpression of HOTTIP in ovarian cancer cell lines and clinical tissues. Further, we showed that higher level of HOTTIP was associated with poor survival of ovarian cancer patients. Notably, HOTTIP silencing restrained proliferation, migration, and invasiveness of ovarian carcinoma cells. On the other hand, upregulation of HOTTIP remarkably exacerbated the aggressive traits of ovarian carcinoma cells. In addition, HOTTIP served as a sponge of miR-615-3p to upregulate SMARCE1 level. Further, upregulation of miR-615-3p or downregulation of SMARCE1 reversed the carcinogenic impacts of HOTTIP in ovarian cancer. HOTTIP and miR-615-3p expression levels in ovarian cancer cells were negatively correlated, whereas HOTTIP and SMARCE1 expression levels were positively correlated. In nude mice, downregulation of HOTTIP reduced cell growth in vivo. In summary, lncRNA HOTTIP promotes the growth and metastatic phenotypes of ovarian cancer via regulating miR-615-3p/SMARCE1 pathway.

Exosomal Transfer of lncRNA H19 Promotes Erlotinib Resistance in Non-Small Cell Lung Cancer via miR-615-3p/ATG7 Axis.

BACKGROUND: Drug resistance restrains the effect of drug therapy in non-small cell lung cancer (NSCLC). However, the mechanism of the acquisition of drug resistance remains largely unknown. This study aims to investigate the effect of exosomal lncRNA H19 on erlotinib resistance in NSCLC and the underlying mechanism. METHODS: HCC827 and A549 cells were continuously grafted into erlotinib-containing culture medium to establish erlotinib-resistant cell lines. The expression of H19 and miR-615-3p was detected by qRT-PCR. The protein levels of MMP2, MMP9, CD9, CD63 and ATG7 were measured by Western blot. Cell viability and proliferation were determined by Cell Counting Kit-8 (CCK-8) and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, respectively. Migration and invasion were assessed by transwell assay. Xenograft tumor models were used to investigate the effect of H19 on erlotinib resistance in vivo. Online software and dual-luciferase reporter assay were used to predicate the downstream targets and confirm the targeted relationships. RESULTS: H19 was upregulated in erlotinib-resistant cells, and knockdown of H19 inhibited cell proliferation, migration and invasion in erlotinib-resistant cells. Extracellular H19 can be packaged into exosomes. Exosomes containing H19 induced erlotinib resistance of sensitive cells, while knockdown of H19 abolished this effect. miR-615-3p was a target of H19 and can bind to ATG7. Exosomal H19 affected erlotinib resistance of erlotinib-resistant NSCLC cells via targeting miR-615-3p to regulate ATG7 expression. In addition, the serum exosomal H19 was upregulated in patients with erlotinib resistance. Furthermore, downregulated H19 decreased the resistance of tumor cells to erlotinib in vivo. CONCLUSION: Our study demonstrated that exosomal H19 facilitated erlotinib resistance in NSCLC via miR-615-3p/ATG7 axis, which might provide a potential target for the diagnosis and treatment of NSCLC.

miR-615 Fine-Tunes Growth and Development and Has a Role in Cancer and in Neural Repair.

MicroRNAs (miRNAs) are small noncoding RNAs that function as epigenetic modulators regulating almost any gene expression. Similarly, other noncoding RNAs, as well as epigenetic modifications, can regulate miRNAs. This reciprocal interaction forms a miRNA-epigenetic feedback loop, the deregulation of which affects physiological processes and contributes to a great diversity of diseases. In the present review, we focus on miR-615, a miRNA highly conserved across eutherian mammals. It is involved not only during embryogenesis in the regulation of growth and development, for instance during osteogenesis and angiogenesis, but also in the regulation of cell growth and the proliferation and migration of cells, acting as a tumor suppressor or tumor promoter. It therefore serves as a biomarker for several types of cancer, and recently has also been found to be involved in reparative processes and neural repair. In addition, we present the pleiad of functions in which miR-615 is involved, as well as their multiple target genes and the multiple regulatory molecules involved in its own expression. We do this by introducing in a comprehensible way the reported knowledge of their actions and interactions and proposing an integral view of its regulatory mechanisms.

miR-615-3p promotes the epithelial-mesenchymal transition and metastasis of breast cancer by targeting PICK1/TGFBRI axis.

BACKGROUND: Increasing evidence indicates that epithelial-mesenchymal transition (EMT) can be regulated by microRNAs (miRNAs). miR-615-3p was shown to be involved in tumor development. However, the role of miR-615-3p in the metastasis of breast cancer remains largely unknown. METHODS: The expression of miR-615-3p in breast cancer cells and tissues was assessed by qRT-PCR and situ hybridization assays. Effects of miR-615-3p on tumor metastasis were evaluated with experiments in vitro and mouse model. EMT markers were detected by western blot and immunofluorescence assays. Molecular mechanism of miR-615-3p in the regulation of breast cancer cell metastasis was analyzed by Western Blot, Co-immunoprecipitation, and Luciferase assay. RESULTS: In the present study, we found that miR-615-3p was significantly elevated in breast cancer cells and tissues, especially in those with metastasis. In breast cancer cell lines, stable overexpression of miR-615-3p was sufficient to promote cell motility in vitro, and pulmonary metastasis in vivo, accompanied by the reduced expression of epithelial markers and the increased levels of mesenchymal markers. Further studies revealed that the reintroduction of miR-615-3p increased the downstream signaling of TGF-ß, the type I receptor (TGFBRI) by targeting the 3'-untranslated regions (3'-UTR) of PICK1. PICK1 inhibits the binding of DICER1 to Smad2/3 and the processing of pre-miR-615-3p to mature miR-615-3p in breast cancer cells, thus exerting a negative feedback loop. CONCLUSIONS: Our data highlight an important role of miR-615-3p in the molecular etiology of breast cancer, and implicate the potential application of miR-615-3p in cancer therapy.

Long non-coding RNA HOTTIP promotes hypoxia-induced glycolysis through targeting miR-615-3p/HMGB3 axis in non-small cell lung cancer cells.

Increased glycolysis under hypoxic stress is a fundamentally important feature of non-small cell lung cancer (NSCLC) cells, but molecular mechanisms of hypoxia on glycolysis remain elusive. Herein, we aimed to explore whether lncRNAs and miRNAs are involved in the glycolytic reprogramming under hypoxic conditions. The levels of HOXA transcript at the distal tip (HOTTIP), miR-615-3p and high mobility group box 3 (HMGB3) mRNA were assessed by qRT-PCR. Western blot was performed to determine the protein expression of hexokinase 2 (HK-2) and HMGB3. Glucose consumption and lactate production were analyzed using a respective assay kit. The targeted correlation between miR-615-3p and HOTTIP or HMGB3 was verified using dual-luciferase reporter and RNA immunoprecipition assays. Our data revealed that HOTTIP was upregulated and miR-615-3p was downregulated in NSCLC tissues and cells. Hypoxia induced glycolysis, increased HOTTIP and HMGB3 mRNA levels and repressed miR-615-3p expression in NSCLC cells. HOTTIP deficiency or miR-615-3p expression restoration repressed hypoxia-induced glycolysis. Moreover, HOTTIP acted as a molecular sponge for miR-615-3p and HMGB3 was a direct target of miR-615-3p. The inhibitory effect of HOTTIP deficiency on glycolysis under hypoxic exposure was reversed by miR-615-3p restoration. Additionally, HOTTIP regulated HMGB3 expression by acting as a molecular sponge of miR-615-3p in NSCLC cells. In conclusion, our study suggested that HOTTIP might promote glycolysis under hypoxic conditions at least partly through regulating miR-615-3p/HMGB3 axis in NSCLC cells. Targeting HOTTIP might be a promising therapeutic strategy for NSCLC treatment.

LINC00657 played oncogenic roles in esophageal squamous cell carcinoma by targeting miR-615-3p and JunB.

BACKGROUND: The prognosis of esophageal squamous cell carcinoma (ESCC) is relatively poor due to the absence of efficient treatment. In this manuscript, we have investigated the specific roles and molecular mechanisms of LINC00657 to order to identify novel therapeutic targets for ESCC. METHOD: The LINC00657 expression in ESCC tissues and cell lines were evaluated by quantitative real-time PCR. The expression of LINC00657 in ESCC cells was regulated by lentivirus transfection. Online bioinformatics analysis tools were used to predict the potential targets of LINC00657 and miR-615-3p. TCGA database was used to analyze the prognosis of ESCC patients. Transwell, wound healing assay and MTT were performed to investigate the ESCC cells' biological functions. JunB expression was evaluated by Western blot. RESULT: LINC00657 was moderately increased in ESCC both in vivo and in vitro and up regulated by irradiation. LINC00657 knockdown could inhibit the migration and proliferation of ESCC cells. And downregulation of LINC00657 significantly enhanced the radio-sensitivity. Moreover, LINC00657 could act as a ceRNA to increase the expression of JunB by binding to miR-615-3p. Meanwhile, overexpression of miR-615-3p resulted in anti-tumor effects and led to the down-regulation of JunB. Survival analysis from TCGA indicated that ESCC patients with higher JunB expression had significant poorer prognosis. CONCLUSION: LINC00657 might be involved in regulating ESCC's response to radiation; and it functioned as an oncogene in ESCC by targeting miR-615-3p and JunB, providing novel potential therapeutic targets.

miR-615-3p promotes proliferation and migration and inhibits apoptosis through its potential target CELF2 in gastric cancer.

Gastric cancer incidence is relatively higher in China than that in developed countries; however, molecular mechanisms considering the initiation and progression of gastric cancer are still unclear. For decades, numerous microRNAs have been found to regulate a wide range of biological functions in gastric cancer. However, the oncogenic function of miR-615-3p in gastric cancer has not been reported to date. With the help of gene and microRNA chips in 10 patients, we were able to screen differential expressed genes and microRNAs compared with normal gastric tissues. After that, online bioinformatics analysis tools were used to predict microRNAs' potential targets. As a result, miR-615-3p and its potential target, CELF2, were selected for further experiments. QRT-PCR and western blot results indicated the aberrant high expression of miR-615-3p and low expression of CELF2 in gastric cancer both in vivo and in vitro. Moreover, miR-615-3p expression correlated to T and M stage. Up regulation of miR-615-3p inhibited the apoptosis, promoted proliferation and migration and led to the down-regulation of CELF2. Meanwhile, down-regulation of miR-615-3p resulted in anti-tumor effects. Immunochemistry staining of CELF2 showed its association with T, N and M stage. In addition, overexpression of CELF2 could reverse miR-615-3p's oncogenic functions stated before. These findings indicate that miR-615-3p promotes gastric cancer proliferation and migration by suppressing CELF2 expression for the first time, providing clues for future clinical practices.

MiR-615-3p inhibits the osteogenic differentiation of human lumbar ligamentum flavum cells via suppression of osteogenic regulators GDF5 and FOXO1.

Ossification of the ligamentum flavum (OLF) is a disease of heterotopic ossification in spinal ligaments. The key of the OLF pathogenesis is the differentiation of fibroblasts into osteoblasts. In this study, we explored the role of miR-615-3p in the osteogenic differentiation of human LF cells. The expression of miR-615-3p was detected during the osteogenic differentiation of hFOB1.19 human osteoblasts, human BMSCs, and human LF cells. The qPCR results showed that miR-615-3p was being decreased during the osteogenic differentiation of these cell lineages. Then, both gain- and loss-function experiments, respectively performed by single-strand miR-615-3p mimic and antagomir, revealed that miR-615-3p negatively regulated the osteogenesis of hLF cells, manifested by a lighter staining degree with Alizarin Red and a decreased level of osteogenic marker genes, including alkaline phosphatase (ALP), RUNX2, osterix (ostx), osteocalcin (OCN), and osteopontin (OPN). Subsequently, our data on bioinformatic analysis, 3'-UTR luciferase activity assay, and protein level detection indicated that miR-615-3p directly targeted and suppressed the expression of FOXO1 and GDF5. Furthermore, knockdown of either FOXO1 or GDF5 could inhibit the osteogenic differentiation of hLF cells, which displayed a similar effect with the miR-615-3p mimic. In conclusion, miR-615-3p negatively regulates the osteogenic differentiation of hLF cells through post-transcriptionally suppressing osteogenic regulators GDF5 and FOXO1. It can be regarded as a potential target for human OLF therapy.

Identification of microRNA-615-3p as a novel tumor suppressor in non-small cell lung cancer.

Lung cancer is the most frequent cause of mortality in cancer patients; non-small-cell lung cancer (NSCLC) accounts for ~80% of lung cancer cases. MicroRNAs (miRNAs) have been revealed to perform an important role in cancer development and progression. Based on a custom miRNA microarray analysis of patients with NSCLC, miRNA-615-3p (miR-615-3p) downregulation was identified in NSCLC tissues compared with normal lung tissues, which suggested that miR-615-3p acted as a tumor suppressor in lung cancer. The overexpression of miR-615-3p was then validated using 40 pairs of NSCLC and adjacent normal tissue samples using a TaqMan reverse transcription-quantitative polymerase chain reaction assay. In order to investigate the tumor suppressor function of miR-615-3p, the ectopic expression of miR-615-3p in the NSCLC A549, H1299 and H1650 cell lines was established. The results revealed that overexpressed miR-615-3p markedly inhibited cell proliferation and colony formation in the 3 NSCLC cell lines compared with the cells overexpressing the negative control sequence (NC). Additional investigation revealed that miR-615-3p overexpression significantly induced apoptosis and cell cycle arrest at the G1 phase in the A549, H1299 and H1650 cell lines compared with the cells overexpressing NC. Finally, ectopic expression of miR-615-3p was found to repress the cell migration and invasion of the 3 lung cancer cell lines. The results of the present study demonstrate, for the first time, that miR-615-3p functions as a tumor suppressor in NSCLC, and may be a novel potential molecular therapeutic target for patients with NSCLC.

miR-615-3p expression level in bone marrow is associated with tumor recurrence in hepatocellular carcinoma.

The significance of disseminated tumor cells (DTCs) in bone marrow (BM) on tumor recurrence has not been investigated in patients with hepatocellular carcinoma (HCC). The aim of te present study was to clarify the molecular characteristics of DTCs that affect postoperative recurrence based on microRNA (miRNA) expression profiles in clinical HCC patients undergoing curative resection. DTCs were prospectively collected from the BM of preoperative HCC patients using immunomagnetic beads and subjected to miRNA microarray analysis. Microarray analysis of nine HCC patients (n=5 patients with postoperative HCC recurrence, n=4 patients without HCC recurrence) demonstrated that miR-615-3p is significantly upregulated in the DTCs of patients with recurrence compared to the DTCs from patients without recurrence. In vitro experiments demonstrated that the miR-615-3p expression level is significantly correlated with malignant characteristics in HCC cells. These data suggest that miR-615-3p in DTCs may play an important role in postoperative HCC recurrence, which suggests that miR-615-3p is a potential target molecule for regulating postoperative HCC recurrence.