miR-503 regulates metastatic function through Rho guanine nucleotide exchanger factor 19 in hepatocellular carcinoma

ARHGEF19 promotes the growth of breast cancer in vitro and in vivo by the MAPK pathway

OBJECTIVE

To assess the expression of ARHGEF19 in human breast cancer, investigate its role in breast cancer, and clarify the mechanism.

METHODS

Bioinformatics analysis, immunoblot, quantitative PCR, and immunohistochemical (IHC) assays were performed to assess ARHGEF19 expression in breast cancer. CCK-8 and Edu assays were conducted to reveal its role in breast cancer cell proliferation. Flow cytometry (FCM) assays and immunoblot were performed to confirm its effects on breast cancer apoptosis. Immunoblot was also performed to clarify the mechanism. Finally, tumor growth assays were aimed to confirm the role of ARHGEF19 in mice.

RESULTS

We observed that ARHGEF19 was highly expressed in human breast cancer. ARHGEF19 promoted breast cancer cell growth in vitro, and suppressed apoptosis. In addition, we found that ARHGEF19 could activate the MAPK pathway in breast cancer cells. Our findings further confirmed that ARHGEF19 contributed to breast cancer growth in mice.

CONCLUSION

We observed that ARHGEF19 promoted the growth of breast cancer in vitro and in vivo via MAPK pathway, and presume it could serve as a breast cancer therapeutic target.

Hepigenetics: A Review of Epigenetic Modulators and Potential Therapies in Hepatocellular Carcinoma

Hepatocellular carcinoma is the fifth most common cancer worldwide and the second most lethal, following lung cancer. Currently applied therapeutic practices rely on surgical resection, chemotherapy and radiotherapy, or a combination thereof. These treatment options are associated with extreme adversities, and risk/benefit ratios do not always work in patients' favor. Anomalies of the epigenome lie at the epicenter of aberrant molecular mechanisms by which the disease develops and progresses. Modulation of these anomalous events poses a promising prospect for alternative treatment options, with an abundance of felicitous results reported in recent years. Herein, the most recent epigenetic modulators in hepatocellular carcinoma are recapitulated on.

The microRNA-424/503 cluster: A master regulator of tumorigenesis and tumor progression with paradoxical roles in cancer

MicroRNAs (miRNAs) are a group of non-coding RNAs that play a crucial role in post-transcriptional gene regulation and act as indispensable mediators in several critical biological processes, including tumorigenesis, tissue homeostasis, and regeneration. MiR-424 and miR-503 are intragenic miRNAs that are clustered on human chromosome Xq26.3. Previous studies have reported that both miRNAs are dysregulated and play crucial but paradoxical roles in tumor initiation and progression, involving different target genes and molecular pathways. Moreover, these two miRNAs are concomitantly expressed in several cancer cells, indicating a coordinating function as a cluster. In this review, the roles and regulatory mechanisms of miR-424, miR-503, and miR-424/503 cluster are summarized in different types of cancers.

Inhibition of Phosphatidylinositol 3-Kinase γ by IPI-549 Attenuates Abdominal Aortic Aneurysm Formation in Mice

OBJECTIVE

The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signalling pathway plays a pivotal role in abdominal aortic aneurysm (AAA). However, systemic inhibition of this pathway causes serious side effects, thus limiting the clinical use of pan-PI3K inhibitors. In this study, it was hypothesised that the γ subunit of PI3K plays an important role in the PI3K/AKT signalling pathway during AAA, and that specifically targeting PI3Kγ may prevent this process.

METHODS

Aortic specimens were collected from AAA patients and organ donors. Furthermore, a classical AAA model in male C57BL/6 mice was created via an intra-aortic porcine pancreatic elastase (PPE) infusion and aortas were collected. A specific PI3Kγ inhibitor, IPI-549, was administered to mice orally. The protein expression level of PI3Kγ was examined by immunohistochemistry and western blotting. The aortic leukocytes were examined by immunohistochemistry and flow cytometry.

RESULTS

PI3Kγ protein levels were elevated in the aortas of AAA patients and PPE infused mice. Three color immunofluorescence staining revealed the predominant area of PI3Kγ by T cells and macrophages in aneurysmal aortas. IPI-549 treatment significantly prevented AAA formation in mice. Aortic macrophages, T cells and neo-angiogenesis were significantly reduced in mice treated with IPI-549 compared with vehicle treated PPE infused mice. Flow cytometry analysis also revealed that CD45⁺ leukocytes and CD45⁺ F4/80⁺ macrophages in IPI-549 treated mouse aortas decreased dramatically. Additionally, IPI-549 treatment inhibited the phosphorylation of AKT in experimental aneurysmal lesions.

CONCLUSION

Specific inhibition of PI3Kγ limits AAA formation. Targeting PI3Kγ prevents inflammatory cell infiltration through inhibition of AKT phosphorylation in AAA.

MicroRNA Regulation of the Small Rho GTPase Regulators-Complexities and Opportunities in Targeting Cancer Metastasis

The small Rho GTPases regulate important cellular processes that affect cancer metastasis, such as cell survival and proliferation, actin dynamics, adhesion, migration, invasion and transcriptional activation. The Rho GTPases function as molecular switches cycling between an active GTP-bound and inactive guanosine diphosphate (GDP)-bound conformation. It is known that Rho GTPase activities are mainly regulated by guanine nucleotide exchange factors (RhoGEFs), GTPase-activating proteins (RhoGAPs), GDP dissociation inhibitors (RhoGDIs) and guanine nucleotide exchange modifiers (GEMs). These Rho GTPase regulators are often dysregulated in cancer; however, the underlying mechanisms are not well understood. MicroRNAs (miRNAs), a large family of small non-coding RNAs that negatively regulate protein-coding gene expression, have been shown to play important roles in cancer metastasis. Recent studies showed that miRNAs are capable of directly targeting RhoGAPs, RhoGEFs, and RhoGDIs, and regulate the activities of Rho GTPases. This not only provides new evidence for the critical role of miRNA dysregulation in cancer metastasis, it also reveals novel mechanisms for Rho GTPase regulation. This review summarizes recent exciting findings showing that miRNAs play important roles in regulating Rho GTPase regulators (RhoGEFs, RhoGAPs, RhoGDIs), thus affecting Rho GTPase activities and cancer metastasis. The potential opportunities and challenges for targeting miRNAs and Rho GTPase regulators in treating cancer metastasis are also discussed. A comprehensive list of the currently validated miRNA-targeting of small Rho GTPase regulators is presented as a reference resource.

MicroRNAs Involved in Metastasis of Hepatocellular Carcinoma: Target Candidates, Functionality and Efficacy in Animal Models and Prognostic Relevance

Hepatocellular carcinoma (HCC) is responsible for the second-leading cancer-related death toll worldwide. Although sorafenib and levantinib as frontline therapy and regorafenib, cabazantinib and ramicurimab have now been approved for second-line therapy, the therapeutic benefit is in the range of only a few months with respect to prolongation of survival. Aggressiveness of HCC is mediated by metastasis. Intrahepatic metastases and distant metastasis to the lungs, lymph nodes, bones, omentum, adrenal gland and brain have been observed. Therefore, the identification of metastasis-related new targets and treatment modalities is of paramount importance. In this review, we focus on metastasis-related microRNAs (miRs) as therapeutic targets for HCC. We describe miRs which mediate or repress HCC metastasis in mouse xenograft models. We discuss 18 metastasis-promoting miRs and 35 metastasis-inhibiting miRs according to the criteria as outlined. Six of the metastasis-promoting miRs (miR-29a, -219-5p, -331-3p, 425-5p, -487a and -1247-3p) are associated with unfavourable clinical prognosis. Another set of six down-regulated miRs (miR-101, -129-3p, -137, -149, -503, and -630) correlate with a worse clinical prognosis. We discuss the corresponding metastasis-related targets as well as their potential as therapeutic modalities for treatment of HCC-related metastasis. A subset of up-regulated miRs -29a, -219-5p and -425-5p and down-regulated miRs -129-3p and -630 were evaluated in orthotopic metastasis-related models which are suitable to mimic HCC-related metastasis. Those miRNAs may represent prioritized targets emerging from our survey.

MiR-503 suppresses cell proliferation and invasion of gastric cancer by targeting HMGA2 and inactivating WNT signaling pathway

Background

Abnormal expression of microRNAs (miRNAs) is related to human carcinogenesis. Although previous studies have shown that miR-503 expression in gastric cancer (GC) is downregulated, however, the underlying molecular mechanism for miR-503 involved in gastric cancer development is still largely unknown.

Methods

The relative expression of miR-503 in GC tissues and adjacent normal tissues was examined using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) analyses. In vitro, cell proliferation and invasion were evaluated by using CCK8, cell colony and transwell invasion assays. In vivo, xenograft tumor model was constructed to assess miR-503 expression whether affects tumor growth or not. Luciferase reporter assay, qRT-PCR and western blot assay were used to demonstrate HMGA2 is a target of miR-503.

Results

We demonstrated that miR-503 expression was significantly downregulated in GC tissues and cell lines compared to adjacent normal tissues and normal gastric mucosa cell lines, respectively. Lower miR-503 expression associated with tumor size, lymph node metastasis, and predicted a poor overall survival (OS) time in GC patients. Subsequently, in vitro, gain-function and loss-function assays confirmed that miR-503 overexpression significantly suppressed GC cell proliferation, colony formation and cell invasion, while decreased miR-503 expression had an adverse effect in GC cells. Furthermore, we found that miR-503 specifically targeted the 3′-UTR regions of HMGA2 mRNA and suppressed its protein expression. Overexpression of HMGA2 could reverse the miR-503 mediated inhibition of GC cell proliferation and invasion. In vivo, miR-503 overexpression dramatically reduced tumor growth. Moreover, we demonstrated that miR-503 suppressed WNT/β-catenin signaling by elevating GSK-3β and p-β-catenin expression, but decreased p-GSK-3β and β-catenin expression in GC cells.

Conclusion

These results provide that miR-503 expression acts as a predictor for GC prognosis and may have a potential application in GC therapy.

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

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

Emerging Roles of Ephexins in Physiology and Disease

Dbl (B-cell lymphoma)-related guanine nucleotide exchange factors (GEFs), the largest family of GEFs, are directly responsible for the activation of Rho family GTPases and essential for a number of cellular events such as proliferation, differentiation and movement. The members of the Ephexin (Eph-interacting exchange protein) family, a subgroup of Dbl GEFs, initially were named for their interaction with Eph receptors and sequence homology with Ephexin1. Although the first Ephexin was identified about two decades ago, their functions in physiological and pathological contexts and regulatory mechanisms remained elusive until recently. Ephexins are now considered as GEFs that can activate Rho GTPases such as RhoA, Rac, Cdc42, and RhoG. Moreover, Ephexins have been shown to have pivotal roles in neural development, tumorigenesis, and efferocytosis. In this review, we discuss the known and proposed functions of Ephexins in physiological and pathological contexts, as well as their regulatory mechanisms.

Long noncoding RNA miR503HG, a prognostic indicator, inhibits tumor metastasis by regulating the HNRNPA2B1/NF-κB pathway in hepatocellular carcinoma

Long noncoding RNAs (lncRNAs) have been associated with hepatocellular carcinoma (HCC), but the underlying molecular mechanisms of their specific association with hepatocarcinogenesis have not been fully explored.

Methods: miR503HG was identified by microarray and validated by real-time PCR. Survival analysis was evaluated using the Kaplan-Meier method and assessed using the log-rank test. In vitro and in vivo assays were preformed to explore the biological effects of miR503HG in HCC cells. The interaction of miR503HG with HNRNPA2B1 was identified by RNA pull-down and RNA immunoprecipitation. Expression of HNRNPA2B1 was examined by western blotting, immunofluorescence and immunohistochemical analyses, while HNRNPA2B1 ubiquitination was detected by immunoprecipitation.

Results: We have identified 713 differentially expressed lncRNAs in 12 pairs of HCC tissues compared with corresponding noncancerous liver tissues. One of these lncRNAs, miR503HG, the host gene of miR503, is markedly decreased in HCC. Expression level of miR503HG is significantly associated with the time to recurrence and overall survival and is an independent risk factor for recurrence and survival. Enhanced expression of miR503HG could noticeably inhibit HCC invasion and metastasis in vitro and in vivo. Further investigation suggested that miR503HG could specifically interact with the heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1). miR503HG promoted HNRNPA2B1 degradation via the ubiquitin-proteasome pathway, which reduced the stability of p52 and p65 mRNA, and simultaneously suppressed the NF-κB signaling pathway in HCC cells. In addition, miR503HG can function synergistically with miR503 to inhibit HCC migration.

Conclusion: Our findings support a role for miR503HG in tumor recurrence risk and survival prediction in HCC patients. We demonstrate a novel mechanism by which miR503HG inhibits the NF-κB signaling pathway and exerts its metastatic tumor suppression function through modulating the ubiquitination status of HNRNPA2B1.

microRNA-503 suppresses the migration, proliferation and colony formation of prostate cancer cells by targeting tumor protein D52 like 2

The present study investigated the expression of microRNA-503 (miR-503) and its effect and mechanism of action on prostate cancer. Tumor tissues and tumor-adjacent tissues were collected from 20 patients with prostate cancer. TargetScan was used to predict the miRNA molecule that interacts with tumor protein D52 like 2 (TPD52L2). DU145 cells were transfected with a negative control, miR-503 mimic or miR-503 inhibitor. DU145 cells that had not undergone transfection were used as a control. Levels of miR-503 and TPD52L2 mRNA were determined using reverse transcription-quantitative polymerase chain reaction and the expression of TPD52L2 protein was measured using western blot analysis. The migration ability of DU145 cells was evaluated using a Transwell assay and cell proliferation was examined using an MTT assay. A flat plate colony formation test was conducted to examine the colony formation rate of DU145 cells. The current study demonstrated that TPD52L2 expression is increased while miR-503 expression is decreased in prostate cancer tissues. Overexpression of miR-503 inhibited the transcription and translation of TPD52L2 in DU145 cells and reduced cell migration, proliferation and colony formation. By contrast, inhibition of miR-503 expression increased the expression of TPD52L2 in DU145 cells and increased cell migration, proliferation and colony formation. The present study demonstrated that miR-503 is an oncogene that regulates the migration, proliferation and colony formation of prostate cancer cells by targeting the TPD52L2 gene. Thus, miR-503 has the potential to become a target for the molecular treatment and prognosis of prostate cancer in the future.

MiR-503 modulates epithelial-mesenchymal transition in silica-induced pulmonary fibrosis by targeting PI3K p85 and is sponged by lncRNA MALAT1

Silicosis is a kind of chronic, progressive and incurable lung fibrotic diseases with largely unknown and complex pathogenesis and molecular mechanisms. Mounting evidence suggests that microRNAs (miRNAs, miRs) are involved in the pathogenesis of silicosis. Our previous study based on miRNA microarray had shown that the expression levels of miR-503 were down-regulated in mouse lung tissues of silica-induced pulmonary fibrosis. Here, we validated the decreased expression of miR-503 in the fibrotic mouse lung tissues, human bronchial epithelial cells (HBE) and human lung adenocarcinoma A549 cells which were exposed to silica. In addition, overexpressed miR-503 inhibited silica-induced pulmonary fibrosis by attenuating the severity and the distribution of lesions in vivo and limiting the process of epithelial-mesenchymal transition (EMT) in vitro. Our molecular study further demonstrated that PI3K p85 is one of the target genes of miR-503 and the downstream molecules (Akt, mTOR and Snail) are tightly associated with EMT. Furthermore, the up-regulated lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), acted as a competing endogenous RNA (ceRNA), can directly bound to miR-503, which indicated that lncRNA MALAT1 may modulate the expression of miR-503 thus triggering the activation of downstream fibrotic signaling pathways. Taken together, our data suggested that MALAT1-miR-503-PI3K/Akt/mTOR/Snail pathway plays critical roles in silica-induced pulmonary fibrosis.

Downregulation of miR-503 Promotes ESCC Cell Proliferation, Migration, and Invasion by Targeting Cyclin D1

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers in China, but the underlying molecular mechanism of ESCC is still unclear. Involvement of microRNAs has been demonstrated in cancer initiation and progression. Despite the reported function of miR-503 in several human cancers, its detailed anti-oncogenic role and clinical significance in ESCC remain undefined. In this study, we examined miR-503 expression by qPCR and found the downregulation of miR-503 expression in ESCC tissue relative to adjacent normal tissues. Further investigation in the effect of miR-503 on ESCC cell proliferation, migration, and invasion showed that enhanced expression of miR-503 inhibited ESCC aggressive phenotype and overexpression of CCND1 reversed the effect of miR-503-mediated ESCC cell aggressive phenotype. Our study further identified CCND1 as the target gene of miR-503. Thus, miR-503 functions as a tumor suppressor and has an important role in ESCC by targeting CCND1.

MiR-503 inhibits hepatocellular carcinoma cell growth via inhibition of insulin-like growth factor 1 receptor

MicroRNAs (miRs) have been demonstrated to play key roles in the development and progression of hepatocellular carcinoma (HCC). However, the regulatory mechanism of miR-503 in HCC has not been fully uncovered. In this study, we found that miR-503 was significantly downregulated in HCC tissues compared to nontumorous liver tissues. Moreover, lower miR-503 levels were associated with the malignant progression of HCC, and the expression of miR-503 was also decreased in several common HCC cell lines compared to normal human liver cell line THLE-3. Overexpression of miR-503 inhibited proliferation but induced apoptosis of LM3 and HepG2 cells. Bioinformatical analysis and luciferase reporter assay further identified insulin-like growth factor 1 receptor (IGF-1R) as a novel target of miR-503 in 293T cells. Moreover, overexpression of miR-503 led to a significant decrease in the protein levels of IGF-1R, while knockdown of miR-503 enhanced its protein levels in LM3 and HepG2 cells. Besides, overexpression of IGF-1R reversed the effects of miR-503-mediated HCC cell proliferation and apoptosis, indicating that IGF-1R acts as a downstream effector of miR-503 in HCC cells. Furthermore, IGF-1R was found to be significantly upregulated in HCC tissues compared to nontumorous liver tissues. In addition, the mRNA levels of IGF-1R were inversely correlated to the miR-503 levels in the HCC tissues. Thus, we demonstrate that miR-503 inhibits the proliferation and induces the apoptosis of HCC cells, partly at least, by directly targeting IGF-1R, and suggest that IGF-1R may serve as a promising target for the treatment of HCC.

GATA3-driven expression of miR-503 inhibits prostate cancer progression by repressing ZNF217 expression

Although increasing evidence demonstrated that deregulation of mircoRNA-503 (miRNA-503) contributes to tumorigenesis, little is known about the biological role and intrinsic regulatory mechanisms of miR-503 in prostate cancer (PCa). In present study, we found that miR-503 was significantly downregulated in advanced PCa tissues and cell lines. Downregulation of miR-503 was strongly associated with aggressive clinical-pathological features and poor prognosis in PCa patients. Ectopic expression of miR-503 significantly inhibited tumor cells growth, cell migration and invasion in vitro and in vivo. Mechanistic studies revealed that ZNF217 was a direct target downstream target of miR-503. Knockdown of ZNF217 mimicked the tumor-suppressive effects of miR-503 overexpression on PCa invasion, whereas ZNF217 overexpression attenuated the tumor-suppressive function of miR-503. Subsequently, miR-503 further modulated the activation of ZNF217-downstream epithelial-mesenchymal transition (EMT) genes. Besides, we also found that GATA3 directly increased miR-503 expression and thus decreased ZNF217 expression, indicating the involvement of GATA3/miR-503/ZNF217 signaling in EMT process. Collectively, our results demonstrated that GATA3-driven expression of miR-503 inhibits PCa progression by repressing ZNF217 expression, and also implicated the potential application of miR-503 in PCa therapy.

miRNA-503 Promotes Tumor Progression and Is Associated with Early Recurrence and Poor Prognosis in Human Colorectal Cancer

OBJECTIVES

MicroRNA (miR)-503 is downregulated in several cancers and plays a tumor-suppressive role in carcinogenesis. However, the miR-503 expression pattern, its clinical significance and its molecular mechanism in colorectal cancer (CRC) have not been investigated.

METHODS

We analyzed miR-503 expression in normal mucosa (n = 20), adenoma (n = 27) and CRC (n = 20). We quantified miR-503 expression in an independent cohort (n = 191) and investigated the clinical significance of miR-503 in CRC. CRC cell lines were transfected with anti-miR-503 to assess its function and target gene.

RESULTS

miR-503 expression increased according to the adenoma-carcinoma sequence. High miR-503 expression was significantly associated with large tumor size, serosal invasion, lymphatic and venous invasion as well as lymph node metastasis. CRC patients with high miR-503 expression had significantly earlier relapse and poorer prognosis than those with low expression. miR-503 was an independent recurrence marker in stage I/II CRC. In vitro, attenuated miR-503 expression resulted in inhibition of proliferation, invasion and migration and acquisition of anoikis of CRC cells. The putative target gene (calcium-sensing receptor) was significantly upregulated after miR-503 attenuation.

CONCLUSIONS

miR-503 acts as an 'onco-miR' in CRC. High miR-503 expression is associated with early recurrence and poor prognosis in CRC.

Increased expression of microRNA-503 and reduced expression of kangai-1 in B-cell non-Hodgkin's lymphoma

The aim of the present study was to determine the expression levels of microRNA-503 (miR-503) and the tumor suppressor gene, kangai-1 (KAI1), in B-cell non-Hodgkin's lymphoma (B-NHL). A total of 45 patients with B-NHL (including 29 cases with stage III/IV disease and 16 cases with stage I/II disease) were enrolled in this study. In addition, 26 patients with reactive lymphoid hyperplasia (RLH) were enrolled as the control patients. Reverse transcription-quantitative polymerase chain reaction was performed in order to measure the expression levels of miR-503 in B-NHL and RLH tissues, and to detect the expression levels of miR-503 and KAI1 in peripheral blood samples. In addition, KAI1 expression levels in B-NHL and RLH tissues were detected using western blotting and immunohistochemical analysis. The expression levels of miR-503 were found to be significantly increased in the tissues and peripheral blood of B-NHL patients when compared with those in RLH patients (P<0.05). However, KAI1 was strongly expressed in RLH tissues and weakly expressed in B-NHL tissues. Furthermore, the expression levels of KAI1 were significantly decreased in the tissues and peripheral blood of B-NHL patients when compared with those in the tissues and peripheral blood of RLH patients (P<0.05). The expression levels of miR-503 in the tissues and peripheral blood of patients with stage III/IV B-NHL were significantly higher compared with those with stage I/II B-NHL (P<0.05). By contrast, the expression levels of KAI1 in stage III/IV B-NHL tissues were significantly higher compared with those in stage I/II B-NHL tissues (P<0.05). In conclusion, miR-503 was highly expressed, whereas KAI1 was poorly expressed, in the tissues and peripheral blood of B-NHL patients. Thus, miR-503 may have an application as a novel therapeutic and diagnostic marker in B-NHL patients.

MicroRNA-503 acts as a tumor suppressor in osteosarcoma by targeting L1CAM

Deregulated microRNAs and their roles in tumorigenesis have attracted much attention in recent years. Although miR-503 was shown to be important in tumorigenesis, its role in osteosarcoma remains unknown. In this study, we focused on the expression and mechanisms of miR-503 in osteosarcoma development. We found that miR-503 was down-regulated in osteosarcoma cell lines and primary tumor samples, and the restoration of miR-503 reduced cell proliferation, migration and invasion. Low level of miR-503 in patients with osteosarcoma was associated with considerably shortened disease-free survival. Furthermore, bioinformatic prediction and experimental validation revealed that the anti-tumor effect of miR-503 was probably exerted through targeting and repressing of L1CAM expression. L1CAM was up-regulated in osteosarcoma cell lines and primary tumor samples and the expression level of L1CAM were negatively correlated with miR-503 levels in osteosarcoma tissues. Collectively, our data identify the important roles of miR-503 in osteosarcoma pathogenesis, indicating its potential application in cancer therapy.

miR-144 suppresses the proliferation and metastasis of hepatocellular carcinoma by targeting E2F3

MicroRNAs (miRNAs) play essential roles in the progression of hepatocellular carcinoma (HCC). miR-144 acts as a tumor suppressor in some malignancies, while its role in HCC is unclear. Here, we found that miR-144 was significantly decreased in HCC tissues and cell lines. Forced overexpression of miR-144 remarkably reduced cell proliferation, increased apoptosis, and suppressed migration and invasion of HCC cells. E2F transcription factor 3 (E2F3) was identified as a target of miR-144 in HCC cells. Moreover, E2F3 overexpression partially attenuated the tumor suppressive effects of miR-144, and the expression of E2F3 was negatively correlated with miR-144 level in HCC tissues. Our data suggest that miR-144 might suppress the growth and motility of HCC cells partially by targeting E2F3.