miR-874 suppresses the proliferation and metastasis of osteosarcoma by targeting E2F3

The Landscape of microRNAs in Bone Tumor: A Comprehensive Review in Recent Studies

Cancer, the second greatest cause of mortality worldwide, frequently causes bone metastases in patients with advanced-stage carcinomas such as prostate, breast, and lung cancer. The existence of these metastases contributes to the occurrence of skeletal-related events (SREs), which are defined by excessive pain, pathological fractures, hypercalcemia, and spinal cord compression. These injurious incidents leave uncomfortably in each of the cancer patient's life quality. Primary bone cancers, including osteosarcoma (OS), chondrosarcoma (CS), and Ewing's sarcoma (ES), have unclear origins. MicroRNA (miRNA) expression patterns have been changed in primary bone cancers such as OS, CS, and ES, indicating a role in tumor development, invasion, metastasis, and treatment response. These miRNAs are persistent in circulation and exhibit distinct patterns in many forms of bone tumors, making them potential biomarkers for early detection and treatment of such diseases. Given their crucial regulatory functions in various biological processes and conditions, including cancer, this study aims to look at miRNAs' activities and possible contributions to bone malignancies, focusing on OS, CS, and ES. In conclusion, miRNAs are valuable tools for diagnosing, monitoring, and predicting OS, CS, and ES outcomes. Further research is required to fully comprehend the intricate involvement of miRNAs in these bone cancers and to develop effective miRNA-based treatments.

Signal Pathways and microRNAs in Osteosarcoma Growth and the Dual Role of Mesenchymal Stem Cells in Oncogenesis

The major challenges in Osteosarcoma (OS) therapy are its heterogeneity and drug resistance. The development of new therapeutic approaches to overcome the major growth mechanisms of OS is urgently needed. The search for specific molecular targets and promising innovative approaches in OS therapy, including drug delivery methods, is an urgent problem. Modern regenerative medicine focuses on harnessing the potential of mesenchymal stem cells (MSCs) because they have low immunogenicity. MSCs are important cells that have received considerable attention in cancer research. Currently, new cell-based methods for using MSCs in medicine are being actively investigated and tested, especially as carriers for chemotherapeutics, nanoparticles, and photosensitizers. However, despite the inexhaustible regenerative potential and known anticancer properties of MSCs, they may trigger the development and progression of bone tumors. A better understanding of the complex cellular and molecular mechanisms of OS pathogenesis is essential to identify novel molecular effectors involved in oncogenesis. The current review focuses on signaling pathways and miRNAs involved in the development of OS and describes the role of MSCs in oncogenesis and their potential for antitumor cell-based therapy.

MicroRNA-874 targets phosphomevalonate kinase and inhibits cancer cell growth via the mevalonate pathway

The microRNA (miR) miR-874, a potential tumour suppressor, causes cell death via target gene suppression in various cancer types. Mevalonate pathway inhibition also causes cell death in breast cancer. However, the relationship between the mevalonate pathway and miR-874-induced apoptosis or its association with the tumour suppressor p53 has not been elucidated. We identified phosphomevalonate kinase (PMVK), a key mevalonate pathway enzyme, and sterol regulatory element-binding factor 2 (SREBF2), the master cholesterol biosynthesis regulator, as direct miR‑874 targets. Next-generation sequencing analysis revealed a significant miR-874-mediated downregulation of PMVK and SREBF2 gene expression and p53 pathway enrichment. Luciferase reporter assays showed that miR-874 directly regulated PMVK and SREBF2. miR-874-induced apoptosis was p53 dependent, and single-cell RNA sequencing analysis demonstrated that miR-874 transfection resulted in apoptosis and p53 pathway activation. Downregulation of PMVK expression also caused cell cycle arrest and p53 pathway activation, which was rescued by geranylgeranyl pyrophosphate (GGPP) supplementation. Analysis of The Cancer Genome Atlas (TCGA) database indicated a negative correlation between miR-874 and PMVK expression and between miR-874 and SREBF2 expression. These findings suggest that miR-874 suppresses the mevalonate pathway by targeting SREBF2 and PMVK, resulting in GGPP depletion, which activates the p53 pathway and promotes cycle arrest or apoptosis.

Molecular mechanism, regulation, and therapeutic targeting of the STAT3 signaling pathway in esophageal cancer (Review)

Esophageal cancer (EC) is the seventh most common cancer globally, and the overall 5‑year survival rate is only 20%. Signal transducer and activator of transcription 3 (STAT3) is aberrantly activated in EC, and its activation is associated with a poor prognosis. STAT3 can be activated by canonical pathways such as the JAK/STAT3 pathway as well as non‑canonical pathways including the Wnt/STAT3 and COX2/PGE2/STAT3 pathways. Activated STAT3, present as phosphorylated STAT3 (p‑STAT3), can be transported into the nucleus to regulate downstream genes, including VEGF, cyclin D1, Bcl‑xL, and matrix metalloproteinases (MMPs), to promote cancer cell proliferation and induce resistance to therapy. Non‑coding RNAs, including microRNAs (miRNAs/miRs), circular RNAs (circRNAs), and long non‑coding RNAs (lncRNAs), play a vital role in regulating the STAT3 signaling pathway in EC. Several miRNAs promote or suppress the function of STAT3 in EC, while lncRNAs and circRNAs primarily promote the effects of STAT3 and the progression of cancer. Additionally, various drugs and natural compounds can target STAT3 to suppress the malignant behavior of EC cells, providing novel insights into potential EC therapies.

miR-874: An Important Regulator in Human Diseases

miR-874 is located at 5q31.2, which is frequently deleted in cancer. miR-874 is downregulated in 22 types of cancers and aberrantly expressed in 18 types of non-cancer diseases. The dysfunction of miR-874 is not only closely related to the diagnosis and prognosis of tumor patients but also plays an important role in the efficacy of tumor chemotherapy drugs. miR-874 participates in the ceRNA network of long non-coding RNAs or circular RNAs, which is closely related to the occurrence and development of cancer and other non-cancer diseases. In addition, miR-874 is also involved in the regulation of multiple signaling pathways, including the Wnt/β-catenin signaling pathway, Hippo signaling pathway, PI3K/AKT signaling pathway, JAK/STAT signaling pathway, and Hedgehog signaling pathway. This review summarizes the molecular functions of miR-874 in the biological processes of tumor cell survival, apoptosis, differentiation, and tumorigenesis, and reveal the value of miR-874 as a cancer biomarker in tumor diagnosis and prognosis. Future work is necessary to explore the potential clinical application of miR-874 in chemotherapy resistance.

miR-874-3p mitigates cisplatin resistance through modulating NF-κB/inhibitor of apoptosis protein signaling pathway in epithelial ovarian cancer cells

The resistance to cisplatin, the most common platinum chemotherapy drug, may confine the efficacy of treatment in epithelial ovarian cancer patients. Aberrant expression of inhibitor of apoptosis proteins set the stage for resistance to cisplatin in EOC; besides, chemosensitivity in EOC can be chalked up to dysregulation of specific miRNAs. Herein, we investigated whether there is a potential correlation between miR-874-3p and the X-chromosome-linked inhibitor of apoptosis, a member of the IAP protein family in cisplatin-resistant EOC cells. The lower expression of miR-874-3p was found in SKOV3-DDP cells; it was also in association with cisplatin-resistance in EOC cells. XIAP was found to contribute to developing platinum resistance and is an authentic target for miR-874-3p in SKOV3-DDP cells. Consistently, restoration of miR-874-3p expression reversed cisplatin resistance in such cells by modulating XIAP and NF-κB/Survivin signaling pathway. Besides, siRNA knock down of XIAP in SKOV3-DDP cells had an anti-migratory effect like those with miR-874 overexpression. Importantly, the enforced expression of XIAP rescued SKOV3-DDP cells from the cytotoxic effects of miR-874-3p. Finally, miR-874-3p sensitized EOC cells to cisplatin-induced apoptosis, at least in part, through targeting XIAP. The cytotoxic effects of miR-874-3p can be attributed to the targeting XIAP in cisplatin-resistant EOC cells. We believe that the combination of cisplatin with miR-874-3p may make a potential strategy to reverse cisplatin resistance.

Inhibition of hsa_circ_0003489 shifts balance from autophagy to apoptosis and sensitizes multiple myeloma cells to bortezomib via miR-874-3p/HDAC1 axis

BACKGROUND

Circular RNAs (circRNAs) crucially regulate tumor progression. In this study, we examined the functional roles and mechanisms of hsa_circ_0003489 in multiple myeloma (MM).

METHODS

Upon altering the expressions of hsa_circ_0003489, miR-874-3p, and/or histone deacetylase 1 (HDAC1) in MM1.R cells and treating them with bortezomib (BTZ), cell viability was examined by CCK-8 assay; cell proliferation by Ki-67 immunofluorescence; apoptosis by TUNEL staining, flow cytometry, and western blot; and autophagy by electron microscopy and western blot. The interaction between hsa_circ_0003489 and miR-874-3p as well as that between miR-874-3p and HDAC1 was examined by expressional analysis, dual luciferase reporter assay, and RNA immunoprecipitation. The in vivo impacts of hsa_circ_0003489 on MM growth and sensitivity to BTZ were examined using an MM xenograft mouse model.

RESULTS

Knocking down hsa_circ_0003489 significantly inhibited the viability, cell proliferation, and autophagy, while promoting the apoptosis of MM cells in vitro and MM xenograft in vivo. Suppressing hsa_circ_0003489 also further boosted the cytotoxic effects of BTZ in MM cells and reversed its promoting effect on autophagy. Mechanically, hsa_circ_0003489 acted as a sponge of miR-874-3p and positively regulated the expression of miR-874-3p target, HDAC1. MiR-874-3p and HDAC1 essentially mediated the effects of hsa_circ_0003489 on cell viability, proliferation, apoptosis, and autophagy.

CONCLUSION

The hsa_circ_0003489/miR-874-3p/HDAC1 axis critically regulates the balance between apoptosis and autophagy. Silencing hsa_circ_0003489 sensitizes MM cells to BTZ by inhibiting autophagy and thus may boost the therapeutic effects of BTZ.

Exosomal-lncRNA DLEU1 Accelerates the Proliferation, Migration, and Invasion of Endometrial Carcinoma Cells by Regulating microRNA-E2F3

Purpose

Long non-coding RNAs (lncRNAs) may act as oncogenes in several cancers, including endometrial carcinoma (EC). The purpose of the current study is to investigate the regulatory mechanism of exosomal-lncRNA deleted in lymphocytic leukemia1 (DLEU1) on EC.

Methods

The expression levels of lncRNA DLEU1, microRNA-381-3p and E2F Transcription Factor 3 (E2F3) in EC tissues or cells were detected using quantitative reverse transcription–polymerase chain reaction (qRT-PCR). We then analysed the proliferation, migration, and invasion of EC cells by performing the MTT assay, wound healing assay, and transwell invasion assay, respectively. Identification of exosomes was detected using Western blot assay. The uptake of exosomes was detected by a confocal microscope. The effects of exosomes on EC cells were investigated by construction of cell co-culture system. The interactions among DLEU1, miR-381-3p and E2F3 were confirmed using the dual-luciferase reporter (DLR) assay.

Results

LncRNA DLEU1 expression was highly up-regulated in EC tissues and cells. Knockdown of DLEU1 inhibited the proliferation, migration, and invasion of EC cells. Exosomes could be uptaken by the ambient EC cells. MiR-381-3p was a target of DLEU1 and was negatively modulated by DLEU1. Overexpression of miR-381-3p suppressed the proliferation, migration, and invasion of EC cells. Additionally, E2F3 was the target gene of miR-381-3p and was negatively modulated by miR-381-3p. Upregulation of miR-381-3p and down-regulation of E2F3 reversed the promoting effect of exosomal DLEU1 on EC cells.

Conclusion

Exosomal DLEU1 accelerates the development of EC by regulating the miR-381-3p/E2F3 axis, thus DLEU1 may act as a possible therapeutic target for treating EC.

MiR-874 Inhibits Cell Proliferation, Migration, and Invasion of Glioma Cells and Correlates with Prognosis of Glioma Patients

Previous studies showed that miR-874 expression was abnormally expressed in many tumors. However, the potential role of miR-874 in glioma remains a mystery. This study aimed to investigate its expression, clinical significance, and cellular function in glioma. A total of 105 glioma patients were enrolled in the present study. The RT-qPCR analysis was used to detect the expression of miR-874 in glioma tissues and cells. The χ² test was used to analyze the association between miR-874 expression and clinical characteristics of patients. Kaplan-Meier method and multivariate Cox regression assays were used to analyze the prognostic value of miR-874 in glioma. Cell counting kit-8 and Transwell assays were used to explore the alterations in a series of cancer-related phenotypes affected by miR-874, including cell proliferation, migration, and invasion capacities. The expression of miR-874 was significantly downregulated in human glioma tissue specimens and cell lines. Furthermore, the expression of miR-874 was associated with tumor size, KPS, and WHO grade. The decreased expression of miR-874 was associated with shorter overall survival. Then functional assays indicated that upregulation of miR-874 suppressed proliferation, migration, and invasion of glioma cells in vitro. The present study indicated that miR-874 inhibited cell proliferation, migration, and invasion of glioma cells and might be a novel prognostic biomarker and potential therapeutic target for glioma.

MicroRNA‑145‑5p inhibits osteosarcoma cell proliferation by targeting E2F transcription factor 3

Osteosarcoma is a common type of bone tumor that primarily occurs in children and young adults. MicroRNA (miRNA/miR) dysregulation is associated with the progression of osteosarcoma; therefore, the aim of the present study was to investigate the biological functions and molecular mechanisms of miR-145-5p in osteosarcoma. The expression of miR-145-5p in osteosarcoma tissues and cell lines was quantified using reverse transcription-quantitative PCR (RT-qPCR). The effect of miR-145-5p on the proliferation of osteosarcoma cells was detected using Cell Counting Kit-8 and colony formation assays, as well as cell cycle distribution analysis. The effect of miR-145-5p on tumor growth was further investigated in vivo using a subcutaneous tumor model in nude mice. The interaction between miR-145-5p and E2F transcription factor 3 (E2F3) was determined using bioinformatics analysis, a luciferase assay, RT-qPCR and western blotting. The results revealed that miR-145-5p expression was decreased in osteosarcoma cell lines and tissues compared with the corresponding normal controls. Increased miR-145-5p expression inhibited the proliferation and colony formation ability of osteosarcoma cells, and induced G₁ phase arrest. Furthermore, mice injected with tumor cells overexpressing miR-145-5p exhibited smaller tumors than those in the control group. Further investigation revealed that miR-145-5p binds to and decreases the expression of E2F3. In addition, the mRNA levels of E2F3 were negatively associated with miR-145-5p in osteosarcoma tissues, and increasing E2F3 expression abrogated the inhibitory effects of miR-145-5p on osteosarcoma cells. Collectively, the results obtained in the present study suggest that miR-145-5p may suppress the progression of osteosarcoma, and may serve as a useful biomarker for the diagnosis of osteosarcoma, as well as a therapeutic target.

Knockdown of lncRNA HOXA-AS2 Inhibits Viability, Migration and Invasion of Osteosarcoma Cells by miR-124-3p/E2F3

Background

Osteosarcoma (OS) is one of the most frequent bone malignancies. Long noncoding RNAs (lncRNAs) have been revealed to participate in many cancers, including OS. This study aimed to explore the biological function of lncRNA homeobox A cluster antisense RNA2 (HOXA-AS2) and its potential mechanism in OS progression.

Methods

Twenty-seven OS patients were recruited for this study. U2OS and MG-63 cells were cultured for in vitro analyses. The levels of HOXA-AS2, microRNA-124-3p (miR-124-3p) and E2F transcription factor 3 (E2F3) were measured by quantitative real-time polymerase chain reaction or Western blot. OS progression was investigated by cell viability, migration and invasion using cell counting kit-8 or trans-well assay. The interaction among HOXA-AS2, miR-124-3p and E2F3 was explored by bioinformatics analysis, luciferase reporter assay, RNA immunoprecipitation and biotinylated RNA pull-down. Xenograft model was established by injecting U2OS cells into nude mice.

Results

HOXA-AS2 expression was increased in OS tissues and cells and associated with poor survival of patients. Knockdown of HOXA-AS2 inhibited cell viability, migration and invasion in OS cells. miR-124-3p could bind with HOXA-AS2 and its deficiency reversed the suppressive role of HOXA-AS2 knockdown. Moreover, E2F3 acted as a target of miR-124-3p and positively regulated by HOXA-AS2. Silence of E2F3 suppressed OS progression, which was abolished by miR-124-3p exhaustion. Interference of HOXA-AS2 attenuated U2OS xenograft tumor growth via upregulating miR-124-3p and downregulating E2F3.

Conclusion

HOXA-AS2 silence impeded OS progression possibly by functioning as a decoy of miR-124-3p to target E2F3, indicating novel evidence of HOXA-AS2 as a promising therapeutic target of OS.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

Insights into the roles of miRNAs; miR-193 as one of small molecular silencer in osteosarcoma therapy

Today, cancer is one of the most common causes of death. Osteosarcoma (OS) is a tumor in long bones and its prevalence is high in teenagers and young people. Among the methods that used to treat cancer, one can name chemotherapy, surgery, and radiotherapy. Since these methods have some disadvantages and they are not absolutely successful, the use of microRNAs (miRNAs) is very useful in diagnosis and treatment of OS. MiRNAs are small non-coding RNA molecules, containing 18-25 nucleotides, which are involved in the regulation of gene expression via binding to messenger RNA (mRNA). These RNAs are divided into two classes of suppressors and oncogenes. During OS, there is aberrant expression of several miRNAs. Among these miRNAs are downregulation of miR-193 that has been associated with cancer occurrence. The aim of the current manuscript is to have overview on the treatment approaches of OS with special focus on miR-193.

Genetic testing for high-grade osteosarcoma: a guide for future tailored treatments?

INTRODUCTION

Genetic characterization of osteosarcoma has evolved during the last decade, thanks to the integrated application of conventional and new candidate-driven and genome-wide technologies. Areas covered: This review provides an overview of the state of art in genetic testing applied to osteosarcoma, with particular regard to novel candidate genetic biomarkers that can be analyzed in tumor tissue and blood samples, which might be used to predict toxicity and prognosis, detect disease relapse, and improve patients' selection criteria for tailoring treatment. Expert commentary: Genetic testing based on modern technologies is expected to indicate new osteosarcoma-related prognostic markers and driver genes, which may highlight novel therapeutic targets and patients stratification biomarkers. The definition of tailored or targeted treatment approaches may improve outcome of patients with localized tumors and, even more, of those with metastatic disease, for whom progress in cure probability is highly warranted.

MicroRNA-874 targeting SUFU involves in osteoblast proliferation and differentiation in osteoporosis rats through the Hedgehog signaling pathway

Osteoporosis is widely viewed as a major public health concern, but the exact magnitude of the problem is uncertain. MicroRNAs play a key role in maintaining bone development and metabolism. This study aims to investigate the effects that microRNA-874 (miR-874) has on osteoblast proliferation and differentiation in osteoporosis rats by targeting SUFU through the Hedgehog signaling pathway. Twenty Wistar female rats were selected for following experiment, and another 20 rats were served as the normal group. Their osteogenic tissues were obtained and the positive expression of SUFU in tissues was determined. Rat osteoblasts were isolated and. The targeting relationship between SUFU and miR-874 was verified and the expression of miR-874, SUFU, Sonic Hedgehog (Shh), Ptch, Smoothened (Smo), bone morphogenetic protein (BMP2), Runx2, proliferating cell nuclear antigen (PCNA) and Bcl-2 associated X protein (Bax) were identified. Besides, cell viability apoptosis, and differentiation were confirmed respectively. Moreover, calcium nodules were observed. Overexpression of SUFU and Bax but lower expression of miR-874, Shh, Ptch, Smo, BMP2, Runx2, and PCNA were found in osteoporosis mice. Besides, elevated expression of miR-874, Shh, Ptch, Smo, BMP2, Runx2 and PCNA, as well as increased cell viability, ALP activity and calcium nodules but decreased expression of SUFU and Bax, and reduced cell apoptosis were confirmed when treated with miR-874 mimic. And it is reciprocal when miR-874 was inhibited. Our study demonstrated that through targeted inhibition of SUFU and activation of Hedgehog signaling pathway, miR-874 could promote the proliferation and differentiation of osteoblasts in osteoporosis rats.

MiR-874 alleviates renal injury and inflammatory response in diabetic nephropathy through targeting toll-like receptor-4

Diabetic nephropathy (DN) is a kind of diabetic complication with capillary damage, and its pathogenesis remains obscure. Recently, microRNAs have been identified as diagnostic biomarkers in various diseases including DN. Toll-like receptor 4 (TLR4) contributes to inflammation, and it has been implicated in diabetes pathophysiology. This study was designed to investigate the role of miR-874 and TLR4 in a streptozotocin (STZ)-induced DN rat model and glucose-induced mouse podocyte model. In the current study, we reported that miR-874 was markedly downregulated in DN rats and glucose-induced mouse podocytes compared with the corresponding control groups with the activation of TLR4. In addition, we observed that overexpression of miR-874 was able to alleviate renal injury in DN rats. The cell counting kit (CCK-8) assay and 5-Ethynyl-2'-deoxyuridine (EdU) assay demonstrated that glucose simulation significantly inhibited podocyte proliferation and induced cell apoptosis, which can be reversed by miR-874 mimics significantly. Notably, miR-874 overexpression dramatically attenuated the inflammatory response, indicated by the decreased levels of interleukin-6, L-1β, and tumor necrosis factor α (TNF-α). Finally, the binding correlation between miR-874 and TLR4 was confirmed by carrying out dual-luciferase reporter assay in our study. It was found that overexpression of miR-874 depressed TLR4 levels in podocytes. These findings implied for the first time that the overexpression of miR-874 repressed glucose-triggered podocyte injury through targeting TLR4 and suggested that miR-874/TLR4 axis might represent a pathological mechanism of DN.

MicroRNA‑874 prohibits the proliferation and invasion of retinoblastoma cells by directly targeting metadherin

MicroRNAs (miRNAs/miRs) serve important roles in regulating gene expression by directly binding to the 3'‑untranslated regions of target genes. Multiple miRNAs are dysregulated in retinoblastoma (RB) and their dysregulation is closely related to RB malignancy. Therefore, exploring the detailed roles of miRNAs in RB is valuable to facilitate the development of effective therapeutic targets for patients with this disease. miRNA‑874‑3p (miR‑874) has been recently reported to be downregulated in several types of human cancer and serves an essential role in cancer progression. However, the expression pattern and detailed roles of miR‑874 in RB, as well as the underlying molecular mechanisms in RB, have not been clearly elucidated. Therefore, this study detected miR‑874 expression in RB tissues and cell lines. The biological roles of miR‑874 in RB were determined and the underlying mechanisms of its actions in RB cells were also examined. This study revealed that miR‑874 expression was aberrantly underexpressed in RB tissues and cell lines. However, returning miR‑874 expression restricted the proliferative and invasive abilities of RB cells. In terms of the underlying mechanism, metadherin (MTDH) was validated as a direct target gene of miR‑874 in RB cells. MTDH inhibition could imitate the inhibitory roles of miR‑874 overexpression in RB cells. Furthermore, forced MTDH expression partially reversed the suppressive effects of miR‑874 on RB cells. In conclusion, this study revealed that miR‑874 may inhibit RB progression by directly targeting MTDH. Restoration of miR‑874 expression may be a novel strategy for preventing the rapid growth and metastasis of RB cells.

MicroRNA‑874 inhibits proliferation and invasion of pancreatic ductal adenocarcinoma cells by directly targeting paired box 6

Studies have demonstrated that a number of microRNAs (miRNAs) are dysregulated in pancreatic ductal adenocarcinoma (PDAC), and alterations in their expression may affect the onset and progression of PDAC. Therefore, the expression patterns, biological functions and associated molecular mechanisms of miRNAs in PDAC should be elucidated for the development of novel therapeutic methods. Previous studies reported significant miRNA‑874 (miR‑874) dysregulation in multiple types of human cancer. However, the expression pattern, possible roles and underlying mechanisms of miR‑874 in PDAC remain to be elucidated. This study evaluated miR‑874 expression in PDAC and examined its biological functions and underlying mechanism of action in PDAC progression. miR‑874 expression was downregulated in PDAC tissues and cell lines. Functional experiments demonstrated that upregulation of miR‑874 inhibited cell proliferation and invasion in PDAC. Additionally, paired box 6 (PAX6) was predicted as a putative target of miR‑874 using bioinformatics analysis. Further experiments demonstrated that PAX6 may be the direct target gene of miR‑874 in PDAC. PAX6 knockdown exhibited similar inhibitory effects to miR‑874 overexpression in PDAC cells. In addition, restored PAX6 expression may reverse the suppressive roles of miR‑874 overexpression in PDAC cells. The results demonstrated that miR‑874 may serve tumor suppressive roles in PDAC by directly targeting PAX6. Therefore, miR‑874 may exhibit potential applications for treatment of patients with PDAC.

MicroRNA‑433 reduces cell proliferation and invasion in non‑small cell lung cancer via directly targeting E2F transcription factor 3

MicroRNAs (miRNA/miRs) have been associated with the initiation and progression of non‑small‑cell lung cancer (NSCLC). Hence, a comprehensive understanding of the association between dysregulated miRNAs and NSCLC may contribute to the identification of novel therapeutic methods for patients with NSCLC. MiRNA‑433 (miR‑433) has been reported to be dysregulated in numerous types of human cancers; however, its expression pattern, biological roles and associated mechanisms in NSCLC require further investigation. The present study aimed to detect miR‑433 expression and determine its roles and underlying molecular mechanisms in NSCLC. In the present study, reverse transcription‑quantitative polymerase chain reaction revealed that miR‑433 was significantly downregulated in NSCLC tissues and cell lines. This decreased miR‑433 expression was strongly associated with the tumor node metastasis stage and lymph node metastasis of patients with NSCLC. Cell Counting kit‑8 and cell invasion assays revealed that the resumption of miR‑433 expression decreased the proliferation and invasion of NSCLC cells. Bioinformatics analysis predicted E2F transcription factor 3 (E2F3) as a potential target of miR‑433. Luciferase reporter assay, RT‑qPCR and western blot analysis further demonstrated that E2F3 was a direct target of miR‑433 in NSCLC. E2F3 downregulation induced by small interfering RNA exhibited inhibitory effects similar to those of miR‑433 overexpression in NSCLC cells, and the restored E2F3 expression counteracted the suppressive effects on NSCLC cells induced by miR‑433 overexpression. Therefore, miR‑433 may inhibit the progression of NSCLC, at least in part, by targeting E2F3. The present study indicated that miR‑433 may be investigated as an innovative candidate target for the therapy of patients with this fatal disease.

DNA methylation mediated silencing of microRNA-874 is a promising diagnosis and prognostic marker in breast cancer

MicroRNA-874 (miR-874) is downregulated in several human cancers and has been suggested to be a tumor suppressor gene. However, the molecular mechanism of miR-874 downregulation in breast cancer has not been well elucidated. Here we aimed to study the aberrant hyper-methylation of CpG sites with the utility of miR-874 downreregulation in breast cancer and evaluate the clinical function of miR-874 as a prognostic marker. The miR-874 expressions in cells and tissues of two breast cancer lines were measured by real-time PCR. The DNA methylation status of the miR-874 promoter region in 19 pairs of breast cancer and adjacent normal samples was analyzed with Sequenom EpiTYPER MassArray. To evaluate whether miR-874 is a potential prognostic marker in breast cancer, we also explored the clinical long-time follow-up records from The Cancer Genome Atlas (TCGA). We found miR-874 expression was downregulated in 47 pairs of breast cancer tissues. Moreover, univariate and multivariate analysis revealed miR-874 expression may be a prognostic biomarker of overall survival in breast cancer patients. Preconditioning with 5-Aza-CdR in two cell lines elevated miR-874 expressions. The data from Sequenom EpiTYPER MassArray showed that DNA methylation of the promoter region of miR-874 was upregulated and accompanied by decreased miR-874 expression, which was further confirmed by TCGA. After comprehensive considerations, we think miR-874, which might be served as a prognostic biomarker, is mediated by DNA methylation.

Downregulation of miR-874-3p promotes chemotherapeutic resistance in colorectal cancer via inactivation of the Hippo signaling pathway

Overcoming resistance to chemotherapy is an arduous challenge in the treatment of colorectal cancer (CRC), particularly since the underlying molecular mechanisms remain obscure. In the present study, we reported that miR-874-3p was markedly downregulated in CRC tissues compared with that in adjacent normal colorectal epithelial tissues. Upregulation of miR-874-3p attenuated the chemoresistance of CRC cells to 5-fluorouracil (5-FU) in vitro and in vivo. Conversely, inhibition of miR-874-3p yielded an opposite effect. Furthermore, our results demonstrated that miR-874-3p directly inhibited the expression of transcriptional co-activators YAP and TAZ of the Hippo signaling pathway, resulting in the inactivation of the TEAD transcription. Thus, our findings clarify a novel mechanism by which miR-874-3p restores chemotherapeutic sensitivity of CRC to 5-FU, indicating that offering miR-874-3p mimics in combination with 5-FU may serve as a new therapeutic strategy to circumvent the chemoresistance in CRC.

miR-874-3p is down-regulated in hepatocellular carcinoma and negatively regulates PIN1 expression

PIN1 is a peptidyl-prolyl cis/trans isomerase (PPIase) that regulates multiple signaling pathways to control cell fate and is found to be over-expressed in cancers, including hepatocellular carcinoma (HCC). However, the regulation of PIN1 in HCC remains poorly defined. Micro-RNAs (miRNAs) have been reported to play a pivotal role in oncogenesis by targeting the 3'-untranslated region (UTR) of mRNAs encoded by oncogenes and tumour suppressor genes, thereby suppressing the levels of both oncoproteins and tumour suppressors. In this report, we aimed to identify miRNAs that suppress PIN1 expression and to determine their role in HCC. By searching the TargetScan database, miR-874-3p was identified as a potential negative regulator of PIN1. miR-874-3p was demonstrated to bind the 3'UTR of PIN1 mRNA directly to suppress expression of PIN1. Functionally, over-expression of miR-874-3p in HCC cell line PLC/PRF/5 inhibited cell growth and colony formation in-vitro, and promoted cellular apoptosis. Furthermore, these tumour suppressive functions conferred by miR-874-3p were abrogated by over-expression of PIN1. Similarly, expression of miR-874-3p in PLC/PRF/5 with PIN1 knocked-down did not further suppress cellular proliferation, suggesting that PIN1 was a major target of miR-874-3p. More importantly, miR-874-3p was found to be down-regulated in HCC tissues and its expression was negatively correlated with that of PIN1. Down-regulation of miR-874-3p was also associated with poorly differentiated tumour cells, more advanced staging, and inferior patient outcomes. In addition, over-expression of miR-874-3p suppressed tumour growth in vivo. Taken together, our data suggested that miR-874-3p plays a tumour suppressive role in HCC through down-regulation of PIN1.

MicroRNA-152 Suppresses Human Osteosarcoma Cell Proliferation and Invasion by Targeting E2F Transcription Factor 3

MicroRNA-152 (miR-152) expression has been reported to be downregulated in osteosarcoma (OS). However, the role of miR-152 in OS is not well documented. In the present study, we aimed to explore the function and underlying mechanism of miR-152 in OS. We found that miR-152 was underexpressed in OS tissues and cell lines. Decreased miR-152 was inversely correlated with lymph node metastasis and advanced clinical stage. Overexpression of miR-152 significantly inhibited cell proliferation, colony formation, migration, and invasion of OS cells. Bioinformatics analyses showed that miR-152 directly targeted E2F transcription factor 3 (E2F3), as further confirmed by a dual-luciferase reporter assay. E2F3 expression was upregulated and inversely correlated with miR-152 expression level in human OS tissues. Moreover, the inhibitory effects of miR-152 on OS growth and invasion were attenuated by E2F3 overexpression. Taken together, our findings indicated that miR-152 reduced OS growth and invasion by targeting E2F3 and provided new evidence of miR-152 as a potential therapeutic target for OS.

MiRNAs and E2F3: a complex network of reciprocal regulations in human cancers

E2F transcription factor 3 (E2F3) is oncogenic in tumorigenesis. Alterations in E2F3 functions correspond with poor prognosis in various cancers, underscoring their status for the clinical cancer phenotype. Latest reports discovered intricate networks between microRNAs (miRNAs) and E2F3 in regulating the balance of these events, including proliferation, apoptosis, metastasis, as well as drug resistance. miRNAs are non-coding small RNAs which negatively regulate gene expressions post-transcriptionally mainly through 3′-UTR binding of target mRNAs. Increasing evidence shows that E2F3 can be activated/inhibited by numerous miRNAs whose dysregulation has been implicated in malignancy. In turn, miRNAs themselves can be transcriptionally regulated by E2F3, thus forming a negative feedback loop. These findings add a new challenging layer of complexity to E2F3 network. Current understanding of the reciprocal link between E2F3 and miRNAs in human cancers were summarized, which could help to develop potential therapeutic strategies.

Aquaporin 3 facilitates tumor growth in pancreatic cancer by modulating mTOR signaling

Aquaporins (AQP) have been demonstrated to be dysregulated in many human cancers and is thought to be involved in pancreatic carcinogenesis and progression. However, the oncogenic roles and underlying mechanism of AQP in pancreatic ductal adenocarcinoma (PDAC) remain largely unknown. In this study, by data mining of TCGA dataset and CCLE database, we identified that AQP3 is the major AQP expressed in PDAC. Then, the microRNA-874, was demonstrated to be a key regulator of AQP3 expression in PDAC cells. Genetic silencing of AQP3 expression had pronounced effects on cell proliferation and apoptosis of the PDAC cell lines BXPC3 and HPAFII. Introduction of microRNA-874 suppressed cell proliferation and promoted cell apoptosis, whereas inhibition of microRNA-874 had the opposite effect. Mechanistically, by a large-scale proteomic analysis, we revealed that AQP3 was significantly associated the activity of mTOR signaling. Moreover, modulation of AQP3 or microRNA-874 altered mTOR activity as demonstrated by the phosphorylation level of mTOR and its downstream target S6. Taken together, our data, as a proof of principle, suggest that AQP3 can promote tumor growth of pancreatic cancer cells by activating the Mtor signaling pathway and provide a potential therapeutic target in the treatment of PDAC.

Knockdown of E2F3 Inhibits Proliferation, Migration, and Invasion and Increases Apoptosis in Glioma Cells

E2F3a, as a member of the E2F family, is essential for cell division associated with the progression of many cancers. However, the biological effect of E2F3a on glioma is not understood as well. To investigate the functional mechanism of E2F3a in glioma, we examined the expression of E2F3a in glioma tissue and cell lines. We found that E2F3a was upregulated in glioma tissue compared with adjacent tissue, and this was associated with a poor survival rate. E2F3a was highly expressed in glioma cell lines compared with normal HEB cell lines. Knockdown of E2F3a significantly inhibited cell proliferation, promoted G0/G1 phase arrest, elevated apoptosis rates, and suppressed cell migration and invasion. However, overexpression of E2F3a markedly promoted cell proliferation, migration, and invasion and inhibited apoptosis. Moreover, in vivo studies showed that knockdown of E2F3a expression dramatically inhibited U373 tumor growth in a nude mouse model. Results of real-time PCR and Western blot showed that the depletion of E2F3a upregulated the expression levels of cell apoptosis-related proteins and downregulated migration-related proteins. Conversely, E2F3a overexpression downregulated the expression levels of cell apoptosis-related proteins and upregulated migration-related proteins. In conclusion, our results highlight the importance of E2F3a in glioma and provide new insights into the diagnostics and therapeutics of gliomas.

What Is New in the miRNA World Regarding Osteosarcoma and Chondrosarcoma?

Despite the availability of multimodal and aggressive therapies, currently patients with skeletal sarcomas, including osteosarcoma and chondrosarcoma, often have a poor prognosis. In recent decades, advances in sequencing technology have revealed the presence of RNAs without coding potential known as non-coding RNAs (ncRNAs), which provides evidence that protein-coding genes account for only a small percentage of the entire genome. This has suggested the influence of ncRNAs during development, apoptosis and cell proliferation. The discovery of microRNAs (miRNAs) in 1993 underscored the importance of these molecules in pathological diseases such as cancer. Increasing interest in this field has allowed researchers to study the role of miRNAs in cancer progression. Regarding skeletal sarcomas, the research surrounding which miRNAs are involved in the tumourigenesis of osteosarcoma and chondrosarcoma has rapidly gained traction, including the identification of which miRNAs act as tumour suppressors and which act as oncogenes. In this review, we will summarize what is new regarding the roles of miRNAs in chondrosarcoma as well as the latest discoveries of identified miRNAs in osteosarcoma.