MicroRNA-494 suppresses cell proliferation and induces senescence in A549 lung cancer cells

The role of microRNAs in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy with poor prognosis. Despite improvements in its diagnosis and therapy, the prognosis for ICC patients remains poor. An improved understanding of ICC pathogenesis and consequential identification of novel therapeutic targets would improve the prognosis of ICC patients. MicroRNAs (miRNAs) are a class of highly conserved, endogenous, small non‐coding RNA molecules of 18–23 nucleotides in length, which regulate gene expression through complementary base‐pairing with target messenger RNAs and subsequent gene silencing. Several studies have shown deregulated expression of miRNAs in ICC cell lines and tissues, in which these miRNAs play important roles in ICC apoptosis, cell proliferation, invasion, migration and metastasis. In this review, we illustrate the potential role of miRNA in the pathogenesis of ICC and explore the possibilities of using miRNAs as prognostic and diagnostic markers, as well as therapeutic targets in ICC.

MicroRNA‑187 is an independent prognostic factor in lung cancer and promotes lung cancer cell invasion via targeting of PTRF

MicroRNAs (miRNAs) are involved in the progression of different types of cancers giving new hope for cancer treatment. The role and regulatory mechanism of microRNA‑187 (miR‑187) are largely unknown. In the present study, 74 patients with non‑small cell lung cancer (NSCLC) were selected. Tumor tissues and matched normal tissues were collected for determining the expression level of miR‑187. Cell research was performed to detect the function of miR‑187. The expression level was measured and miR‑187 was found to be overexpressed in the NSCLC cell lines and tissues. Overexpression of miR‑187 promoted cell proliferation in the A549 and H1650 cell lines. Moreover, overexpression of miR‑187 also promoted cell migration and invasion. Polymerase I and transcript release factor (PTRF) was identified as a target of miR‑187. Overexpression of miR‑187 suppressed the expression of PTRF. Knockdown of PTRF promoted lung cancer cell invasion, and overexpression of PTRF had a negative effect on lung cancer cell invasion. The PTRF messenger RNA (mRNA) levels in cancer tissues were significantly lower than those in their adjacent normal lung tissues as determined by real‑time PCR (RT‑PCR). The expression of the PTRF protein was significantly weaker than that in the adjacent normal lung tissues using immunohistochemical staining. The findings revealed that miR‑187 promotes cell growth and invasion by targeting PTRF and miR‑187 may be a new prognostic factor for NSCLC.

miR-19a/b modulates lung cancer cells metastasis through suppression of MXD1 expression

Increasing evidence has shown that microRNA (miRNA) is extensively involved in the pathophysiology of lung cancer. Microarray data demonstrated the increasing levels of miR-19a in the peripheral blood from patients suffering from lung cancer, which is closely associated with poor prognosis of lung cancer. However, the underlying molecular mechanism of miR-19a remains to be determined. The results of the present study showed a higher expression of miR-19a compared with normal bronchial epithelial cells. Furthermore, lentivirus vectors were constructed to establish cell lines that overexpressed and knocked out miR-19a in order to study the role of miR-19a on the metastasis and proliferation of lung cancer cells. Investigation into the underlying mechanism of miR-19a, revealed that MXD1 may be the key gene targeting miR-19a, participating in the process of proliferation and metastasis of lung cancer cells.

miR-494-3p Induces Cellular Senescence and Enhances Radiosensitivity in Human Oral Squamous Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is the most common malignancy of head and neck. Although radiotherapy is used for OSCC treatment, the occurrence of radioresistant cancer cells limits its efficiency. MicroRNAs (miRNAs) are non-coding RNAs with lengths of 18–25 base pairs and known to be involved in carcinogenesis. We previously demonstrated that by targeting B lymphoma Mo-MLV insertion region 1 homolog (Bmi1), miR-494-3p functions as a putative tumor suppressor miRNA in OSCC. In this study, we further discovered that miR-494-3p could enhance the radiosensitivity of SAS OSCC cells and induce cellular senescence. The overexpression of miR-494-3p in SAS cells increased the population of senescence-associated β-galactosidase positive cells, the expression of p16^INK4a and retinoblastoma 1 (RB1), as well as downregulated Bmi1. The knockdown of Bmi1 by lentiviral-mediated delivery of specific short hairpin RNAs (shRNAs) also enhanced the radiosensitivity of SAS cells and the activation of the senescence pathway. Furthermore, the inverse correlation between Bmi1 and miR-494-3p expression was observed among OSCC tissues. Results suggest that miR-494-3p could increase the radiosensitivity of OSCC cells through the induction of cellular senescence caused by the downregulation of Bmi1.

miR-494 inhibits ovarian cancer cell proliferation and promotes apoptosis by targeting FGFR2

MicroRNAs (miRs) have been reported to be key regulators in numerous types of cancer. The aim of the present study was to investigate the role of miR-494 in ovarian cancer. Expression of miR-494 was analyzed in ovarian cancer tissues and cell lines by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). miR-494 mimic or negative control was transiently transfected into A2780 and SKOV3 cell lines. A cell counting kit-8 assay was performed to assess the effects of miR-494 on cell proliferation, and flow cytometry was used to evaluate the apoptotic rate. The target gene of miR-494 was detected by luciferase assay. Expression of fibroblast growth factor receptor 2 (FGFR2) was identified using RT-qPCR and western blotting. In the present study, decreased expression of miR-494 was observed in ovarian cancer samples and cell lines. Overexpression of miR-494 inhibited ovarian cancer cell proliferation by inducing apoptosis. Additional investigation indicated that FGFR2 was a direct target of miR-494. Taken together, the results of the present study suggested that miR-494 suppressed ovarian cancer cell proliferation by inducing apoptosis via targeting FGFR2.

By downregulating TIAM1 expression, microRNA-329 suppresses gastric cancer invasion and growth

Gastric cancer (GC) is one of the most common malignant tumors worldwide. Emerging evidence has shown that abnormal microRNAs (miRNAs) expression is involved in tumorigenesis. MiR-329 was previously reported to act as a tumor suppressor or oncogene in some types of cancer. However, its function in gastric cancer (GC) is unclear. Here, we found that miR-329 was down-regulated in GC compared with adjacent controls. Enforced expression of miR-329 inhibited proliferation, migration and invasion of gastric cancer cells in vitro. We identified T lymphoma invasion and metastasis 1 (TIAM1) gene as potential target of miR-329. MiR-329 levels inversely correlated with TIAM1 expression in GC. Importantly, TIAM1 rescued the miR-329-mediated inhibition of cell invasion and proliferation. Finally, reintroduction of miR-329 significantly inhibited tumor formation of GC in the xenograft mice. Our findings suggest that miR-329 is a tumor suppressor and potential therapeutic target of GC

GALNT7, a target of miR-494, participates in the oncogenesis of nasopharyngeal carcinoma

GalNAc-transferase-7 (GALNT7) is essential for the regulation of cell proliferation and has been implicated in tumorigenesis. However, the role of GALNT7 in the development and progression of nasopharyngeal carcinoma (NPC) remains unclear. Our previous study showed that GALNT7 was a putative target of miR-494, which was confirmed by luciferase reporter assay. In the present study, we demonstrated that in vitro knockdown of GALNT7 significantly inhibited the proliferation, colony formation, migration, and invasion of NPC-derived cells. In vivo tumorigenicity assay showed that miR-494 and GALNT7-small interfering RNA (siRNA) reduced tumor growth in nude mice. Taken together, our results provided new evidence for an oncogenic role of GALNT7 in NPC.

Nutrigenetics and Nutrimiromics of the Circadian System: The Time for Human Health

Even though the rhythmic oscillations of life have long been known, the precise molecular mechanisms of the biological clock are only recently being explored. Circadian rhythms are found in virtually all organisms and affect our lives. Thus, it is not surprising that the correct running of this clock is essential for cellular functions and health. The circadian system is composed of an intricate network of genes interwined in an intrincated transcriptional/translational feedback loop. The precise oscillation of this clock is controlled by the circadian genes that, in turn, regulate the circadian oscillations of many cellular pathways. Consequently, variations in these genes have been associated with human diseases and metabolic disorders. From a nutrigenetics point of view, some of these variations modify the individual response to the diet and interact with nutrients to modulate such response. This circadian feedback loop is also epigenetically modulated. Among the epigenetic mechanisms that control circadian rhythms, microRNAs are the least studied ones. In this paper, we review the variants of circadian-related genes associated to human disease and nutritional response and discuss the current knowledge about circadian microRNAs. Accumulated evidence on the genetics and epigenetics of the circadian system points to important implications of chronotherapy in the clinical practice, not only in terms of pharmacotherapy, but also for dietary interventions. However, interventional studies (especially nutritional trials) that include chronotherapy are scarce. Given the importance of chronobiology in human health such studies are warranted in the near future.

The oncogenic triangle of HMGA2, LIN28B and IGF2BP1 antagonizes tumor-suppressive actions of the let-7 family

The tumor-suppressive let-7 microRNA family targets various oncogene-encoding mRNAs. We identify the let-7 targets HMGA2, LIN28B and IGF2BP1 to form a let-7 antagonizing self-promoting oncogenic triangle. Surprisingly, 3′-end processing of IGF2BP1 mRNAs is unaltered in aggressive cancers and tumor-derived cells although IGF2BP1 synthesis was proposed to escape let-7 attack by APA-dependent (alternative polyadenylation) 3′ UTR shortening. However, the expression of the triangle factors is inversely correlated with let-7 levels and promoted by LIN28B impairing let-7 biogenesis. Moreover, IGF2BP1 enhances the expression of all triangle factors by recruiting the respective mRNAs in mRNPs lacking AGO proteins and let-7 miRNAs. This indicates that the downregulation of let-7, largely facilitated by LIN28B upregulation, and the protection of let-7 target mRNAs by IGF2BP1-directed shielding in mRNPs synergize in enhancing the expression of triangle factors. The oncogenic potential of this triangle was confirmed in ovarian cancer (OC)-derived ES-2 cells transduced with let-7 targeting decoys. In these, the depletion of HMGA2 only diminishes tumor cell growth under permissive conditions. The depletion of LIN28B and more prominently IGF2BP1 severely impairs tumor cell viability, self-renewal and 2D as well as 3D migration. In conclusion, this suggests the targeting of the HMGA2-LIN28B-IGF2BP1 triangle as a promising strategy in cancer treatment.

MicroRNAs-491-5p suppresses cell proliferation and invasion by inhibiting IGF2BP1 in non-small cell lung cancer

MicroRNAs-491-5p (miR-491-5p) has been found to involve in tumor initiation and development in several tumors. However, the biological function and underlying molecular mechanism of miR-491-5p in non-small lung cancer (NSCLC) remain unclear. This study was therefore to investigate biological role of and underlying molecular mechanisms of in NSCLC. It was found that miR-491-5p expression was significantly downregulated in NSCLC tissues when compared with corresponding adjacent normal tissues (P<0.01), and the value was negatively related to advanced and tumor-node-metastasis (TNM) stage and lymph node metastasis (both P<0.01). We also demonstrate that restoration of miR-491-5p suppressed NSCLC cell proliferation by arresting NSCLC cells in the G1/G0 phase and accelerating apoptosis. miR-491-5p also inhibited cell migration and invasion in NSCLC cells. Mechanically, IGF2BP1 was identified as direct targets of miR-491-5p. And IGF2BP1 expression was significantly upregulated, and correlated negative with miR-491-5p expression in NSCLC tissues. In vivo assay showed thatmiR-491-5p suppressed tumor growth in nude model by repressing IGF2BP1 expression. Collectively, miR-491-5p functioned as a tumor suppressor in NSCLC by targeting IGF2BP1. Restoration of miR-491-5p expression may represent a promising therapeutic approach for targeting malignant NSCLC.

MicroRNA-541 promotes the proliferation of vascular smooth muscle cells by targeting IRF7

MiRNAs play crucial roles in abnormal proliferation and invasion of VSMCs. However, the roles and mechanisms of miRNAs in VSMCs are not fully understood. In our study, we demonstrated that PDGF-BB and serum induced proliferation of VSMCs led to the upregulation of miR-541. We also showed that overexpression of miR-541 promoted VSMC proliferation and invasion. In addition, Interferon regulatory factor 7 (IRF7) was found to be a potential target of miR-541 and upregulation of IRF7 could inhibit VSMC proliferation. Restored expression of miR-541 promoted IRF7-inhibited VSMCs proliferation. In conclusion, these findings suggest that inhibitors targeting miR-541 or its specific downstream molecules may be therapeutic strategy for VSMC growth-related diseases.

miR-211 suppresses hepatocellular carcinoma by downregulating SATB2

Dysregulation of microRNAs (miRs) is involved in carcinogenesis. Deregulation of miR-211 has recently been observed in many tumors, but its function in hepatocellular carcinoma (HCC) is still unknown. Here we found that miR-211 was decreased in HCC cancer tissues compared with adjacent normal tissues. We also found that overexpression of miR-211 repressed proliferation and invasion in HepG2 and SMMC7721 cells. Luciferase reporter assays and western blot indicated that special AT-rich sequence-binding protein-2 (SATB2), is a direct target of miR-211. The expression of SATB2 was upregulated in HCC cancer tissues and cell lines and miR-211 levels inversely correlated with SATB2 levels in HCC. Importantly, SATB2 rescued the miR-211-mediated inhibition of cell invasion and proliferation. Finally, reintroduction of miR-211 repressed tumor formation of HCC in xenograft mice. This study provides insights into molecular mechanisms that miR-211 contributed to HCC.

MIR494 reduces renal cancer cell survival coinciding with increased lipid droplets and mitochondrial changes

Background

miRNAs can regulate cellular survival in various cancer cell types. Recent evidence implicates the formation of lipid droplets as a hallmark event during apoptotic cell death response. It is presently unknown whether MIR494, located at 14q32 which is deleted in renal cancers, reduces cell survival in renal cancer cells and if this process is accompanied by changes in the number of lipid droplets.

Methods

769-P renal carcinoma cells were utilized for this study. Control or MIR494 mimic was expressed in these cells following which cell viability (via crystal violet) and apoptotic cell numbers (via Annexin V/PI staining) were assessed. By western blotting, MIR494 cellular responses were validated using MIR494 antagomir and Argonaute 2 siRNA. Transmission electron microscopy (TEM) was performed in MIR494-transfected 769-P cells to identify ultrastructural changes. LipidTOX green neutral lipid staining and cholesterol measurements were conducted to assess accumulation of lipids droplets and total cholesterol levels, respectively, in MIR494 expressing 769-P cells. Indirect immunofluorescence and western analyses were also performed to examine changes in mitochondria organization. Co-transfection of MIR494 mimic with siRNA targeting LC3B and ATG7 was conducted to assess their contribution to formation of lipid droplets in MIR494-expressing cells.

Results

MIR494 expression reduces viability of 769-P renal cancer cells; this was accompanied by increased cleaved PARP (an apoptotic marker) and LC3B protein. Further, expression of MIR494 increased LC3B mRNA levels and LC3B promoter activity (2.01-fold; 50 % increase). Interestingly, expression of MIR494 markedly increased multilamellar bodies and lipid droplets (by TEM and validated by LipidTOX immunostaining) while reducing total cholesterol levels. Via immunocytochemistry, we observed increased LC3B-associated endogenous punctae upon MIR494 expression. In contrast to ATG7 siRNA, knockdown of LC3B reduced the numbers of lipid droplets in MIR494-expressing cells. Our results also identified that MIR494 expression altered the organization of mitochondria which was accompanied by co-localization with LC3B punctae, decreased PINK1 protein, and altered Drp1 intracellular distribution.

Conclusion

Collectively, our findings indicate that MIR494 reduces cell survival in 769-P renal cancer cells which is accompanied by increased lipid droplet formation (which occurs in a LC3B-dependent manner) and mitochondrial changes.

Therapeutic Potential of miR-494 in Thrombosis and Other Diseases: A Review

Functional nucleic acids, such as microRNAs (miRNAs), have been implicated in the pathophysiology of many diseases. The miRNA expression profiles of various cancers including haematological malignancies are well defined, but the role of miRNAs in haemostasis and the regulation of coagulation is poorly understood. We identified that miR-494 is oestrogen responsive and directly targets the anticoagulant protein, Protein S, as a mechanism for acquiring Protein S deficiency under high oestrogenic conditions such as during pregnancy and oral contraceptive use. Furthermore, previous studies have also characterised miR-494 to be involved in many biological processes. This paper reviews the current knowledge in the role of miRNAs in regulating haemostatic proteins and the known biological functions of miR-494, highlighting miR-494 as an emerging therapeutic target, with an overview of the strategy we have employed in identifying functional nucleic acids such as miRNAs that target haemostatic factors and the therapeutic potential of miR-494-directed therapy for the treatment of thrombotic disorders.

MicroRNA-613 inhibited ovarian cancer cell proliferation and invasion by regulating KRAS

MicroRNAs (miRNAs) play several important roles in carcinogenesis, and the dysregulation of miRNAs is associated with cancer progression. Little is known about the role of miR-613 in ovarian cancer. In the present study, we demonstrate that miR-613 expression is downregulated in human ovarian cancer cell lines and tissues. Additionally, miR-613 overexpression suppressed ovarian cancer cell proliferation, colony formation, and invasion. Furthermore, KRAS was identified as a target of miR-613. Reintroducing KRAS rescued the inhibitory effects exerted by miR-613 on ovarian cancer cell proliferation and invasion. Taken together, our findings suggest that miR-613 functions as a candidate tumor suppressor miRNA in ovarian cancer by directly targeting KRAS. To the best of our knowledge, this is the first study to show that miR-613 affects the proliferation and invasion of ovarian cancer.

miR-372 suppresses tumour proliferation and invasion by targeting IGF2BP1 in renal cell carcinoma

OBJECTIVES

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that regulate proteins and mRNAs for degradation or translational suppression. Up to now, the role of miR-372 in renal cell carcinoma has remained unknown; in this study, we have aimed to reveal its functional importance in this tumour.

MATERIALS AND METHODS

qRT-PCR was performed to measure expression levels of miR-372 in renal cell carcinoma cell lines and tissues. CCK-8 and an invasion assay were performed to measure its functional role. Luciferase assays, qRT-PCR and western blotting were performed to discover miR-372's target gene.

RESULTS

We demonstrated that miRNA-372 was down-regulated in renal cell carcinoma cell lines and tissue specimens; its over-expression inhibited cell proliferation and invasion. Moreover, we showed that miRNA-372 repressed insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) expression by directly interacting with its putative binding site at the 3'-UTR. Furthermore, ectopic expression of IGF2BP1 significantly reversed suppression of cell proliferation and invasion caused by miR-372 over-expression.

CONCLUSIONS

Our data indicated that miR-372 seemed to function as a tumour suppressor in renal cell carcinoma progression by inhibiting the IGF2BP1 expression.

miR-873 induces lung adenocarcinoma cell proliferation and migration by targeting SRCIN1

microRNAs (miRNAs) are endogenously expressed, conserved and small noncoding RNA that regulate gene expression by the post-transcriptional level. In this study, we aim to examine the role of miR-873 in lung adenocarcinoma. We found that the expression of miR-873 was upregulated in four lung adenocarcinoma cell lines and tissues. In addition, the expression levels of SRCIN1 were inversely correlated with the expression levels of miR-873 in lung adenocarcinoma tissues. Furthermore, SRCIN1 was confirmed asthe direct target of miR-873 by luciferase reporter assay and Western blotting. Overexpression of miR-873 promoted the proliferation and migration of lung adenocarcinoma cells, while SRCIN1 upregulation inhibited their proliferation and migration. Restoration of SRCIN1 could significantly reverse the proliferation and migration promotion imposed by miR-873. In summary, this study reveals for the first time that miR-873 increase the lung adenocarcinoma cell proliferation and migration through directly inhibiting SRCIN1 expression.

MicroRNA-150 functions as a tumor suppressor in osteosarcoma by targeting IGF2BP1

Osteosarcoma (OS) is the most common primary malignant bone tumor with high morbidity in young adults and adolescents. Increasing evidence has demonstrated that aberrant microRNA (miRNA) expression is involved in OS occurrence and development. miR-150 has been recently widely studied in many cancers, but not including OS. This study is aimed to investigate the expression and biological role of miR-150 in OS. Here, we found that miR-150 expression was consistently downregulated in OS tissues and cell lines compared with the matched adjacent normal tissues and human normal osteoblast cells (NHOst), and its expression was significantly correlated with lymph node metastasis and tumor-node-metastasis (TNM) stage. Functional study showed that restoration of miR-150 expression in OS cells could inhibit cell proliferation, migration, and invasion and induced apoptosis in vitro as well as suppressed tumor growth of OS in vivo. Mechanistically, IGF2 mRNA-binding protein 1(IGF2BP1) was confirmed to act as a direct target of miR-150, and the IGF2BP1 mRNA expression was inversely correlated with the level of miR-150 in OS tissues. In addition, downregulation of endogenous IGF2BP1 exhibited similar effects of overexpression of miR-150. Taken together, these findings suggest that miR-150 functions as a tumor suppressor in OS partially by targeting IGF2BP1.

microRNA-762 promotes breast cancer cell proliferation and invasion by targeting IRF7 expression

OBJECTIVES

miRNAs play crucial roles in human tumourigenesis. This study was performed to measure expression and function of miR-762 in breast cancer.

MATERIALS AND METHODS

Expression of miR-762 in breast tissues and cell lines (SK-BR-3, DA-MB-435s, MCF-7 and MDA-MB-231, HBL-100) was measured by using real-time RT-PCR. We restored expression of miR-762 in MCF-7 cells to measure its functional roles. Luciferase assays were performed to reveal the target gene of miR-762.

RESULTS

Expression of miR-762 was high in both breast cancer cell lines and specimens, and its overexpression increased breast cancer cell proliferation and invasion. Interferon regulatory factor 7 (IRF7) is a direct target of miR-762 and overexpression of miR-762 reduced expression of IRF7. Moreover, IRF7 was repressed, its levels inversely correlated to miR-762 expression. IRF7 rescued miR-762-induced cell invasion and proliferation.

CONCLUSIONS

These results demonstrate that miR-762 tumour effect was achieved by targeting IRF7 in human breast cancer specimens.

MicroRNA expression and its implications for diagnosis and therapy of tongue squamous cell carcinoma

Tongue squamous cell carcinoma (TSCC) is the most common type of oral squamous cell carcinomas and is well known for its high rate of lymph nodal metastasis. Despite the identification of many molecular mechanisms in TSCC, the number of deaths associated with TSCC increased during the past 5 years. MicroRNAs (miRNAs) are a family of small non-coding RNA molecules, which regulate gene expression by either translational inhibition or mRNA degradation. miRNAs have been proven to be key regulators of various biological and pathological processes including cell proliferation, development and tumourigenesis. Increasing evidence has demonstrated that the deregulated miRNAs are implicated in the diagnosis and treatment of TSCC. In this review, we summarized the expressions and roles of miRNAs in TSCC and comment on the potential roles of miRNAs in diagnosis, prognosis and treatment of this malignancy.

MicroRNA-495 suppresses human renal cell carcinoma malignancy by targeting SATB1

Deregulated expression of miRNAs is related to progression and initiation of human cancers. Although miR-495 has identified in various tumors, its expression and function in renal cell carcinoma (RCC) is still unknown. In this study, we found that the expression of miR-495 was downregulated in RCC cell lines and tissues. Ectopic expression of miR-495 induced G0/G1 phase arrest and suppressed cell proliferation and migration in RCC cell lines. We further validated SATB1 was a direct target of miR-495 in RCC. In addition, re-expression of SATB1 reversed the miR-495-induced inhibition of cell proliferation and migration. These data suggest that miR-495 functions as a tumor suppressor and may be a promising therapeutic target in RCC in the future.

MicroRNA-411 inhibited matrix metalloproteinase 13 expression in human chondrocytes

Osteoarthritis (OA) is the most common joint degenerative disease affecting the joint structure, leading to loss of joint function and tissue destruction. Recent studies have demonstrated that miRNAs are involved in many pathological conditions, including OA. The study was to investigate the role of miR-411 in the pathogenesis of OA. The expression of miR-411 was downregulated in OA cartilage compared with in normal cartilage. Conversely, the expression of MMP-13 was upregulated in OA cartilage compared with in normal cartilage. IL-1β treatment repressed miR-411 expression in chondrocytes. Moreover, we identified MMP-13 as a direct target gene of miR-411 in chondrocytes and overexpression of miR-411 inhibited the MMP-13 expression. Furthermore, overexpression of miR-411 increased the expression of type II collagen and type IV collagen expression in chondrocytes. MiR-411 is a crucial regulator of MMP-13 in chondrocytes and may response to the development of OA.

miR-506 inhibits the proliferation and invasion by targeting IGF2BP1 in glioblastoma

Increasing evidence has indicated that microRNAs (miRNAs) play an essential role in cancers. Deregulation of miR-506 was reported in several cancers. However, the expression and function of miR-506 in glioblastoma remain unclear. Our data showed that the level of miR-506 was downregulated in glioblastoma tissues and cell lines. Overexpression of miR-506 repressed cell growth, blocked G1/S transition, and suppressed cell invasion in glioblastoma cell. Moreover, IGF2BP1 was a direct target of miR-506 in glioblastoma cells. Knockdown of IGF2BP1 recapitulated the anti-proliferative and anti-invasive effects of miR-506, whereas IGF2BP1 overexpression antagonized the tumor-suppressive function of miR-506. Our data showed that miRNA-506 played a tumor suppressor gene role in human glioblastoma by regulating IGF2BP1 gene and might be a new therapeutic target of human glioblastoma.

Extremely Low-Frequency Electromagnetic Fields Affect the miRNA-Mediated Regulation of Signaling Pathways in the GC-2 Cell Line

Extremely low-frequency electromagnetic fields (ELF-EMFs) can affect male reproductive function, but the underlying mechanism of this effect remains unknown. miRNA-mediated regulation has been implicated as an important epigenetic mechanism for regulatory pathways. Herein, we profiled miRNA expression in response to ELF-EMFs in vitro. Mouse spermatocyte-derived GC–2 cells were intermittently exposed to a 50 Hz ELF-EMF for 72 h (5 min on/10 min off) at magnetic field intensities of 1 mT, 2 mT and 3 mT. Cell viability was assessed using the CCK–8 assay. Apoptosis and the cell cycle were analyzed with flow cytometry. miRNA expression was profiled using Affymetrix Mouse Genechip miRNA 3.0 arrays. Our data showed that the growth, apoptosis or cell cycle arrest of GC–2 cells exposed to the 50 Hz ELF-EMF did not significantly change. However, we identified a total of 55 miRNAs whose expression significantly changed compared with the sham group, including 19 differentially expressed miRNAs (7 miRNAs were upregulated, and 12 were downregulated) in the 1 mT exposure group and 36 (9 miRNAs were upregulated, and 27 were downregulated) in the 3 mT exposure group. The changes in the expression of 15 selected miRNAs measured by real-time PCR were consistent with the microarray results. A network analysis was used to predict core miRNAs and target genes, including miR-30e-5p, miR-210-5p, miR-196b-5p, miR-504-3p, miR-669c-5p and miR-455-3p. We found that these miRNAs were differentially expressed in response to different magnetic field intensities of ELF-EMFs. GO term and KEGG pathway annotation based on the miRNA expression profiling results showed that miRNAs may regulate circadian rhythms, cytokine-cytokine receptor interactions and the p53 signaling pathway. These results suggested that miRNAs could serve as potential biomarkers, and the miRNA-mediated regulation of signaling pathways might play significant roles in the biological effects of ELF-EMFs.

Functional elucidation of miR-494 in the tumorigenesis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma has very high incidence and high mortality worldwide. MiRNA is related to the tumorigenesis and metastasis of a variety of tumors. In the present study, we verify that the expression of miR-494 in NPC tissues and NPC-derived cells was down-regulated, respectively. The proliferation, colony formation, migration, and invasion of NPC-derived cells were suppressed, while the cell apoptosis was promoted, when miR-494 was over-expressed in these cells. GALNT7 and CDK16 were confirmed to be the direct targets of miR-494. These results suggested that miR-494 play an inhibitory role in the tumorigenesis of NPC.

Noncoding RNA control of cellular senescence

Senescent cells accumulate in normal tissues with advancing age and arise by long-term culture of primary cells. Senescence develops following exposure to a range of stress-causing agents and broadly influences the physiology and pathology of tissues, organs, and systems in the body. While many proteins are known to control senescence, numerous noncoding (nc)RNAs are also found to promote or repress the senescent phenotype. Here, we review the regulatory ncRNAs (primarily microRNAs and lncRNAs) identified to-date as key modulators of senescence. We highlight the major senescent pathways (p53/p21 and pRB/p16), as well as the senescence-associated secretory phenotype (SASP) and other senescence-associated events governed by ncRNAs, and discuss the importance of understanding comprehensively the ncRNAs implicated in cell senescence.

MicroRNA-454 functions as an oncogene by regulating PTEN in uveal melanoma

MicroRNAs (miRNAs) regulate gene expression by targeted repression of transcription and translation, and are involved in carcinogenesis. In this study, we demonstrated that the expression of miR-454 was up-regulated in uveal melanoma tissues compared to normal tissues. Ectopic expression of miR-454 resulted in significant promotion of cell proliferation, colony formation, invasion and induction of cell cycle in uveal melanoma cells. Furthermore, we identified PTEN as a direct target of miR-454. Our data revealed that ectopic expression of PTEN restored the effects of miR-454 on cell proliferation and invasion in uveal melanoma cells. These findings support an oncogene role of miR-454 in development of uveal melanoma.

miR-211 promotes non-small cell lung cancer proliferation by targeting SRCIN1

MicroRNAs (miRNAs) are a class of small non-coding RNAs that, when dysregulated, are involved in the initiation and progression of various cancers, including lung cancer, in humans. In the current study, qRT-PCR was performed to measure miR-211 expression in human non-small cell lung cancer (NSCLC) cell lines and tissues. Cell proliferation, cell cycle, colony formation, and invasion were performed to detect the functional role of miR-211 in human NSCLC cell line. We used luciferase reporter assay to find the potential target of miR-211. We found that miR-211 expression was upregulated in human non-small cell lung cancer (NSCLC) cell lines and tissues. The overexpression of miR-211 enhanced NSCLC cell proliferation, colony formation, and invasion. SRC kinase signaling inhibitor 1 (SRCIN1) was identified as a direct target of miR-211. SRCIN1 silencing promoted cell proliferation, and SRCIN1 expression was downregulated in human NSCLC cell lines. Thus, miR-211 may function as an oncogenic miRNA in NSCLC, partly by regulating SRCIN1, and the modulation of miR-211 expression represents a potential strategy for the treatment of NSCLC patients.

PAQR3: a novel tumor suppressor gene

PAQR3, also known as RKTG (Raf kinase trapping to Golgi), is a member of the progestin and adipoQ receptor (PAQR) family. The role of PAQR3 as a tumor suppressor has recently been established in different types of human cancer in which PAQR3 exerts its biological function through negative regulation of the oncogenic Raf/MEK/ERK signaling. Multiple studies have found that PAQR3 downregulation frequently occurs in human cancers and is very often associated with tumor progression and shortened patients' survival. Moreover, restoring the expression of PAQR3 could induce apoptosis and inhibit proliferation and invasiveness of cancer cells. Downregulation of PAQR3 by oncogenic microRNAs has also been reported. In this review, we summarized current knowledge concerning the role of PAQR3 in tumor development. To our knowledge, this is the first review on the role of this novel tumor suppressor.

Overexpression of secretagogin inhibits cell apoptosis and induces chemoresistance in small cell lung cancer under the regulation of miR-494

Secretagogin (SCGN) has recently been identified to play a crucial role in cell apoptosis, receptor signaling and differentiation. However, its clinical significance and functional roles in SCLC chemoresistance remain unknown. Here we examined the expression of SCGN in clinical samples from SCLC patients and evaluated its relation with clinical prognosis. Then up and down-regulation of SCGN were carried out in SCLC cell lines to assess its influence on chemoresistance. Furthermore, luciferase reporter assay was used to evaluate whether SCGN is a novel direct target of miR-494. Our results revealed that elevated expression of SCGN was correlated with the poorer prognosis of SCLC patients and the more significant correlation with chemosensitivity. We also found that knockdown of SCGN expression in H69AR and H446AR cells increased chemosensitivity via increasing cell apoptosis and cell cycle arrest of G0/G1 phase, while over-expression of SCGN reduced chemosensitivity in sensitive H69 and H446 cells. SCGN as a novel target of miR-494 by luciferase reporter assay, up-regulation of miR-494 can sensitize H69AR cells to chemotherapeutic drugs. These results suggest SCGN is involved in the chemoresistance of SCLC under the regulation of miR-494 and may be a potential biomarker for predicting therapeutic response in treatment SCLC.

miR-1275: A single microRNA that targets the three IGF2-mRNA-binding proteins hindering tumor growth in hepatocellular carcinoma

This study aimed to identify a single miRNA or miR (microRNA) which regulates the three insulin-like growth factor-2-mRNA-binding proteins (IGF2BP1, 2 and 3). Bioinformatics predicted miR-1275 to simultaneously target the three IGF2BPs, and screening revealed miR-1275 to be underexpressed in hepatocellular carcinoma (HCC) tissues. Transfection of HuH-7 cells with miR-1275 suppressed IGF2BPs expression and all three IGF2BPs were confirmed as targets of miR-1275. Ectopic expression of miR-1275 and knockdown of IGF2BPs inhibited malignant cell behaviors, and also reduced IGF1R protein and mRNA. Finally IGF1R was validated as a direct target of miR-1275. These findings indicate that the tumor-suppressor miR-1275 can control HCC tumor growth partially through simultaneously regulating the oncogenic IGF2BPs and IGF1R.

miR-494 promotes cell proliferation, migration and invasion, and increased sorafenib resistance in hepatocellular carcinoma by targeting PTEN

MicroRNA-494 (miR-494) acts as an oncomiR and is involved in tumor development, progression and metastasis, and confers resistance to chemotherapeutic drugs by targeting a number of molecules in several human cancers. However, the function and underlying molecular mechanism of miR-494 in hepatocellular carcinoma (HCC) has not been totally elucidated. In the present study, we determined the role played by miR-494 in HCC tissues and HCC cell lines using quantitative RT-PCR (RT-qPCR). The results showed that, miR-494 was significantly upregulated in HCC tissues and HCC cell lines. Additionally, a high miR-494 expression positively correlated with tumor differentiation (P<0.01), TNM stage (P<0.01) and lymph node metastasis (P<0.01). Luciferase reporter assays confirmed that miR-494 binds to the 3'-untranslated region (3'-UTR) of the phosphatase and tensin homolog (PTEN) mRNA and represses its translation. Functional analyses indicated that the upregulation of miR-494 promoted cell viability, migration and invasion, decreased cell apoptosis and cell cycle arrest at G1 stage, and conferred sorafenib resistance to HCC cell lines. Underexpression of PTEN by siRNA significantly attenuated the inhibitory effects of anti-miR-494 on the proliferation, migration and invasion of liver cancer cells. Mechanistic investigations revealed that miR-494 suppressed the expression of PTEN but increased the expression of PI3K and p-Akt, which contribute to the promotion of proliferation, migration and invasion, and increased sorafenib resistance to HCC cell lines. These findings suggested that miR-494 is a potential candidate for HCC therapeutics.

MicroRNA-494 is a master epigenetic regulator of multiple invasion-suppressor microRNAs by targeting ten eleven translocation 1 in invasive human hepatocellular carcinoma tumors

Vascular invasion provides a direct route for tumor metastasis. The degree to which microRNA (miRNA) expression plays a role in tumor vascular invasion is unclear. Here, we report that miR-494 is up-regulated in human hepatocellular carcinoma (HCC) tumors with vascular invasion and can promote HCC cell invasiveness by gene inactivation of multiple invasion-suppressor miRNAs. Our results show that ten eleven translocation (TET) methylcytosine dioxygenase, predominantly TET1 in HCC cells, is a direct target of miR-494. The reduced 5'-hydroxymethylcytosine levels observed in the proximal cytosine-phosphate-guanine (CpG) regions of multiple invasion-suppressor miRNA genes are strongly associated with their transcriptional repression upon miR-494 overexpression, whereas enforced DNA demethylation can abolish the repression. Furthermore, TET1 knockdown shows a similar effect as miR-494 overexpression. Conversely, miR-494 inhibition or enforced TET1 expression is able to restore invasion-suppressor miRNAs and inhibit miR-494-mediated HCC cell invasion.

CONCLUSIONS

miR-494 can trigger gene silencing of multiple invasion-suppressor miRNAs by inhibiting genomic DNA demethylation by direct targeting of TET1, thereby leading to tumor vascular invasion.

Compound 331 selectively induces glioma cell death by upregulating miR-494 and downregulating CDC20

Malignant gliomas are the most common malignant tumors in the central nervous system (CNS). Up to date, the prognosis of glioma is still very poor, effective therapy with less side-effect is very necessary. Herein, we identify a compound named as "331" selectively induced cell death in glioma cells but not in astrocytes. Compound 331 upregulated miR-494 and downregulated CDC20 in glioma cells but not in astrocytes. These results suggest that compound 331 could be a potential drug selectively targeting glioma cells through upregulating miR-494 and downregulating CDC20.

MicroRNA-410 promotes cell proliferation by targeting BRD7 in non-small cell lung cancer

miR-410 acts as an oncogene or tumor suppressor gene in some malignancies. However, its role in NSCLC is still unknown. In this study, we showed that the expression of miR-410 was up-regulated in both human NSCLC tissues and cells. Overexpression of miR-410 promoted cell proliferation, migration, and invasion of NSCLC. In addition, bromodomain-containing protein 7 (BRD7) was a direct target of miR-410. MiR-410-mediated downregulation of BRD7 led to increase Akt phosphorylation. Inhibition of Akt phosphorylation can rescue the effect of miR-410 on NSCLC cell. The expression of BRD7 was downregulated in NSCLC and was inversely expressed with miR-410 in NSCLC. Our data provided new knowledge regarding the role of miR-410 in the lung cancer progression.

MicroRNA expression and its implications for diagnosis and therapy of gallbladder cancer

Gallbladder cancer is the most common biliary tract malignancy with poor prognosis. MicroRNAs (miRNAs) are a class of small, endogenous, non-coding RNAs of 19-23 nucleotides in length, which regulate gene expression at post-transcriptional and translational levels. Several studies have demonstrated aberrant expression of miRNAs in gallbladder cancer tissues. Recent evidences also demonstrated that specific miRNAs are functionally involved in gallbladder cancer development through modulating cell proliferation, apoptosis, migration, invasion and metastasis. In this review, we explore the possibilities of using miRNAs as prognostic, diagnostic markers and therapeutic targets in gallbladder cancer.

Up-Regulation of MiR-300 Promotes Proliferation and Invasion of Osteosarcoma by Targeting BRD7

Increasing reports suggest that deregulated microRNAs (miRNAs) might provide novel therapeutic targets for cancers. However, the expression and function of miR-300 in osteosarcoma is still unknown. In our study, we found that the expression of miR-300 was up-regulated in osteosarcoma tissues and cells compared with paired adjacent non-tumor bone tissues and osteoblastic cells using RT-qPCR. The enforced expression of miR-300 could promote cell proliferation, invasion and epithelial-mesenchymal transition (EMT). Moreover, we identified that bromodomain-containing protein 7 (BRD7), a new tumor suppressor gene, was a direct target of miR-300. Ectopic expression of BRD7 could significantly inhibit miR-300-promoted proliferation, invasion and EMT. Therefore, our results identify an important role for miR-300 in osteosarcoma through regulating BRD7 expression.

The Downregulation of MiR-182 Is Associated with the Growth and Invasion of Osteosarcoma Cells through the Regulation of TIAM1 Expression

Background

Osteosarcoma is the most common primary bone malignancy in children and young adults. Increasing results suggest that discovery of microRNAs (miRNAs) might provide a novel therapeutical target for osteosarcoma.

Methods

MiR-182 expression level in osteosarcoma cell lines and tissues were assayed by qRT-PCR. MiRNA mimics or inhibitor were transfected for up-regulation or down-regulation of miR-182 expression. Cell function was assayed by CCK8, migration assay and invasion assay. The target genes of miR-182 were predicated by bioinformatics algorithm (TargetScan Human).

Results

MiR-182 was down-regulated in osteosarcoma tissues and cell lines. Overexpression of miR-182 inhibited tumor growth, migration and invasion. Subsequent investigation revealed that TIAM1 was a direct and functional target of miR-182 in osteosarcoma cells. Overexpression of miR-182 impaired TIAM1-induced inhibition of proliferation and invasion in osteosarcoma cells.

Conclusions

Down-expression of miR-182 in osteosarcoma promoted tumor growth, migration and invasion by targeting TIAM1. MiR-182 might act as a tumor suppressor gene whose down-regulation contributes to the progression and metastasis of osteosarcoma, providing a potential therapy target for osteosarcoma patients.

PHLPP2 Downregulation Contributes to Lung Carcinogenesis Following B[a]P/B[a]PDE Exposure

PURPOSE

The carcinogenic capacity of B[a]P/B[a]PDE is supported by epidemiologic studies. However, the molecular mechanisms responsible for B[a]P/B[a]PDE-caused lung cancer have not been well investigated. We evaluated here the role of novel target PHLPP2 in lung inflammation and carcinogenesis upon B[a]P/B[a]PDE exposure.

EXPERIMENTAL DESIGN

We used the Western blotting, RT-PCR, [(35)S]methionine pulse and immunohistochemistry staining to determine PHLPP2 downregulation following B[a]P/B[a]PDE exposure. Both B[a]PDE-induced Beas-2B cell transformation model and B[a]P-caused mouse lung cancer model were used to elucidate the mechanisms leading to PHLPP2 downregulation and lung carcinogenesis. The important findings were also extended to in vivo human studies.

RESULTS

We found that B[a]P/B[a]PDE exposure downregulated PHLPP2 expression in human lung epithelial cells in vitro and in mouse lung tissues in vivo. The ectopic expression of PHLPP2 dramatically inhibited cell transformation upon B[a]PDE exposure. Mechanistic studies showed that miR-205 induction was crucial for inhibition of PHLPP2 protein translation by targeting PHLPP2-3'-UTR. Interestingly, PHLPP2 expression was inversely associated with tumor necrosis factor alpha (TNFα) expression, with low PHLPP2 and high TNFα expression in lung cancer tissues compared with the paired adjacent normal lung tissues. Additional studies revealed that PHLPP2 exhibited its antitumorigenic effect of B[a]P/B[a]PDE through the repression of inflammatory TNFα transcription.

CONCLUSIONS

Our studies not only first time identify PHLPP2 downregulation by lung carcinogen B[a]P/B[a]PDE, but also elucidate a novel molecular mechanisms underlying lung inflammation and carcinogenesis upon B[a]P/B[a]PDE exposure.

MiR-144 Inhibits Uveal Melanoma Cell Proliferation and Invasion by Regulating c-Met Expression

MicroRNAs (miRNAs) are a group endogenous small non-coding RNAs that inhibit protein translation through binding to specific target mRNAs. Recent studies have demonstrated that miRNAs are implicated in the development of cancer. However, the role of miR-144 in uveal melanoma metastasis remains largely unknown. MiR-144 was downregulated in both uveal melanoma cells and tissues. Transfection of miR-144 mimic into uveal melanoma cells led to a decrease in cell growth and invasion. After identification of two putative miR-144 binding sites within the 3' UTR of the human c-Met mRNA, miR-144 was proved to inhibit the luciferase activity inMUM-2B cells with a luciferase reporter construct containing the binding sites. In addition, the expression of c-Met protein was inhibited by miR-144. Furthermore, c-Met-mediated cell proliferation and invasion were inhibited by restoration of miR-144 in uveal melanoma cells. In conclusion, miR-144 acts as a tumor suppressor in uveal melanoma, through inhibiting cell proliferation and migration. miR-144 might serve as a potential therapeutic target in uveal melanoma patients.

Prenatal and neonatal exposure to perfluorooctane sulfonic acid results in aberrant changes in miRNA expression profile and levels in developing rat livers

Perfluorooctane sulfonate (PFOS) is an animal carcinogen. However, the underlying mechanism in cancer initiation is still largely unknown. Recently identified microRNAs (miRNAs) may play an important role in toxicant exposure and in the process of toxicant-induced tumorigenesis. We used PFOS to investigate PFOS-induced changes in miRNA expression in developing rat liver and the potential mechanism of PFOS-induced toxic action. Dams received 3.2 mg/kg PFOS in their feed from gestational day 1 (GD1) to postnatal day 7 (PND 7). Pups then had free access to treated feed until PND 7. We isolated RNAs from liver tissues on PND 1 and 7 and analyzed the expression profiles of 387 known rat miRNAs using microarray technology. PFOS exposure induced significant changes in miRNA expression profiles. Forty-six miRNAs had significant expression alterations on PND 1, nine miRNAs on PND 7. Specifically, expression of four miRNAs was up-regulated on PND 7 but down-regulated on PND1 (p < 0.05). Many aberrantly expressed miRNAs were related to various cancers. We found oncogenic and tumor-suppressing miRNAs, which included miR-19b, miR-21*, miR-17-3p, miR-125a-3p, miR-16, miR-26a, miR-1, miR-200c, and miR-451. In addition, four miRNAs were simultaneous significantly expressed on both PND 1 and 7. Functional Annotation analysis of the predicted transcript targets revealed that PFOS exposure potentially alters pathways associated with different cancers (cancer, melanoma, pancreatic cancer, colorectal cancer, and glioma), biological processes which include positive regulation of apoptosis and cell proliferation. Results showed PFOS exposure altered the expression of a suite of miRNAs. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 712-723, 2015.

MicroRNA-494 inhibition protects nucleus pulposus cells from TNF-α-induced apoptosis by targeting JunD

BACKGROUND

Human nucleus pulposus cell (HNPC) apoptosis plays an important role in the development of intervertebral disc degeneration (IVDD). Our previous research revealed that among all of the dysregulated microRNAs in the degenerated nucleus pulposus tissues of patient with IVDD, miRNA-494 (miR-494) is the most significantly increased. However, the influence of miR-494 HNPC apoptosis has not been confirmed.

OBJECTIVE

This study was designed to evaluate the effect of miR-494 on the HNPC apoptosis induced by TNF-α and to explore the possible mechanism of this process.

METHODS

First, HNPCs were stimulated with TNF-α at different concentrations (0 ng/ml, 10 ng/ml, 50 ng/ml, or 100 ng/ml) for 0 h, 8 h, 16 h, or 24 h. Annexin V-PE/7-AAD assays and real-time quantitative PCR were used to detect the cell apoptosis rates and miR-494 expression. Second, we successfully knocked down endogenous miR-494 in HNPCs via lentiviral antigomiR-494 vector infection and then stimulated with TNF-α (100 ng/ml, 16 h). The rates of apoptosis and miR-494 expression were then detected again. Additionally, a dual-luciferase reporter assay and western blotting were used to determine whether JunD is a target of miR-494. Finally, western blotting was used to analyze the expression of cytochrome C.

RESULTS

We found that the rate of apoptosis increased with concentration, time (p < 0.05) and miR-494 expression (p < 0.05). The rate of apoptosis in the 100 ng/ml, 16 h group appeared to be suitable. After transfection, the apoptosis rate and miR-494 expression were significantly decreased in the antigomiR-494+TNF-α group compared to the controls (p < 0.05). We also revealed that JunD is a target of miR-494. Western blotting analysis demonstrated that treatment with the lentiviral antigomiR-494 vector resulted in increased expression of JunD (p < 0.05) and decreased expression of cytochrome C (p < 0.05).

CONCLUSION

These results indicated that miR-494 is a novel regulator of HNPC apoptosis induced by TNF-α. The knock-out of miR-494 expression protected the HNPCs from apoptosis via the up-regulation of JunD, which was possibly mediated via cytochrome C apoptotic signaling. These findings suggest that the miR-494/JunD signaling pathway might represent a novel therapeutic target for the prevention of IVDD.

miR-454 is down-regulated in osteosarcomas and suppresses cell proliferation and invasion by directly targeting c-Met

OBJECTIVES

Osteosarcoma is the most common primary bone malignancy of children and young adults. Increasing evidence has shown that microRNAs (miRNAs) are associated with cancer development, but, little is known concerning the role of miR-454 in osteosarcoma.

MATERIALS AND METHODS

qRT-PCR was performed to detect expression of miR-454 in osteosarcoma cell lines and tissues. To understand its role in osteosarcoma, we reintroduced expression of miR-454 in the MG-63 cell line by transfection with miR-454 mimics or inhibitors. CCK-8 assay and an invasion assay were used to detect the functional role of miR-454. Luciferase assay and western blot analysis were performed to detect the target gene of miR-454.

RESULTS

miR-454 was found to be down-regulated in osteosarcoma tissues and cell lines. Its over-expression inhibited tumour growth and invasion and its down-regulation promoted cell proliferation and invasion. Subsequent investigation revealed that c-Met was a direct and functional target of miR-454 in osteosarcoma. Overexpression of miR-454 impaired c-Met-induced cell proliferation and invasion. Finally, miR-454 was found to be inversely correlated to c-Met expression in human osteosarcoma tissues.

CONCLUSIONS

Reduced-expression of miR-454 in osteosarcoma cells promoted tumour growth by targeting c-Met, thus miR-454 may be a potential therapy target for this tumour.

MiR-506 suppresses tumor proliferation and invasion by targeting FOXQ1 in nasopharyngeal carcinoma

MiRNAs are small noncoding RNAs that play important roles in various biological processes including tumorigenesis. However, little is known about the expression and function of miR-506 in nasopharyngeal carcinoma (NPC). In this study, we showed that miR-506 was downregulated in nasopharyngeal carcinoma (NPC) cell lines and tissues. Ectopic expression of miR-506 dramatically suppressed cell proliferation, colony formation and invasion. Moreover, we identified the Forkhead box Q1 (FOXQ1) gene as a novel direct target of miR-506. MiR-506 exerts its tumor suppressor function through inhibition of the FOXQ1, which was involved in tumor metastasis and proliferation in various cancers. Furthermore, the expression of FOXQ1 is up-regulated in NPC cell lines and tissues. Taken together, our results indicate that miR-506 functions as a tumor suppressor miRNA in NPC and that its suppressive effects are mediated chiefly by repressing FOXQ1 expression.

miRNA-196b inhibits cell proliferation and induces apoptosis in HepG2 cells by targeting IGF2BP1

Background

Tumor hypoxia is one of the features of tumor microenvironment that contributes to chemoresistance. miRNAs have recently been shown to play important roles in tumorigenesis and drug resistance. Moreover, hypoxia also regulates the expression of a series of miRNAs. However, the interaction between chemoresistance, hypoxia and miRNAs has not been explored yet. The aim of this study is to understand the mechanisms activated/inhibited by miRNAs under hypoxia that induce resistance to chemotherapy-induced apoptosis.

Methods

TaqMan low-density array was used to identify changes in miRNA expression when cells were exposed to etoposide under hypoxia or normoxia. The effects of miR-196b overexpression on apoptosis and cell proliferation were studied in HepG2 cells. miR-196b target mRNAs were identified by proteomic analysis, luciferase activity assay, RT-qPCR and western blot analysis.

Results

Results showed that hypoxia down-regulated miR-196b expression that was induced by etoposide. miR-196b overexpression increased the etoposide-induced apoptosis and reversed the protection of cell death observed under hypoxia. By a proteomic approach combined with bioinformatics analyses, we identified IGF2BP1 as a potential target of miR-196b. Indeed, miR-196b overexpression decreased IGF2BP1 RNA expression and protein level. The IGF2BP1 down-regulation by either miR-196b or IGF2BP1 siRNA led to an increase in apoptosis and a decrease in cell viability and proliferation in normal culture conditions. However, IGF2BP1 silencing did not modify the chemoresistance induced by hypoxia, probably because it is not the only target of miR-196b involved in the regulation of apoptosis.

Conclusions

In conclusion, for the first time, we identified IGF2BP1 as a direct and functional target of miR-196b and showed that miR-196b overexpression reverses the chemoresistance induced by hypoxia. These results emphasize that the chemoresistance induced by hypoxia is a complex mechanism.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0349-6) contains supplementary material, which is available to authorized users.

MicroRNA-153 inhibits osteosarcoma cells proliferation and invasion by targeting TGF-β2

Increasing evidence indicates that microRNAs (miRNAs), a class of small noncoding RNAs, participate in almost every step of cellular processes. MiRNAs are aberrantly expressed in human cancers and contribute to cancer development and progression. Study of miRNAs may provide a new clue for understanding the mechanism of carcinogenesis and a new tool for cancer treatment. In the present study, miR-153 was downregulated in human osteosarcoma tissues and cell lines. Introduction of miR-153 mimics into the MG-63 cells inhibited cell proliferation and invasion. Our results further revealed that transforming growth factor beta 2 (TGF-β2) was negatively regulated by miR-153. Furthermore, overexpression of miR-153 decreased p-SMAD2, p-SMAD3, epidermal growth factor receptor (EGFR) and insulin-like growth factor binding protein-3 (IGFBP-3) expressions, which were the downstream signaling molecules of TGF-β. Furthermore, miRNA-153 suppressed TGF-β-mediated MG-63 proliferation and migration. Therefore, our results suggest that miR-153 may act as a tumor suppressor in osteosarcoma through targeting TGF-β2.

MicroRNA dysregulation in uveal melanoma: a new player enters the game

Uveal melanoma is the second most common form of melanoma and a predominant intraocular malignant tumor in adults. The development of uveal melanoma is a multistep process involving genetic and epigenetic alteration of proto-oncogenes and tumor-suppressor genes. Recent discoveries have shed a new light on the involvement of a class of noncoding RNA known as microRNAs (miRNAs) in uveal melanoma. A lot of miRNAs show differential expressions in uveal melanoma tissues and cell lines. Genes coding for these miRNAs have been characterized as novel oncogene and tumor-suppressor genes based on findings that these miRNAs control malignant phenotypes of uveal melanoma cells. Several studies have confirmed that dysregulation of miRNAs promotes cell-cycle progression, confers resistance to apoptosis, and enhances invasiveness and metastasis. Moreover, several miRNAs have also been shown to correlate with uveal melanoma initiation and progression, and thus may be used as biomarkers for early diagnosis and prognosis. Elucidating the biological aspects of miRNA dysregulation may help us better understand the pathogenesis of uveal melanoma and promote the development of miRNA directed-therapeutics against this disease.