Mir-664 promotes osteosarcoma cells proliferation via downregulating of FOXO4

Immunohistochemical Investigation into Protein Expression Patterns of FOXO4, IRF8 and LEF1 in Canine Osteosarcoma

Osteosarcoma (OSA) is the most common type of primary bone malignancy in people and dogs. Our previous molecular comparisons of canine OSA against healthy bone resulted in the identification of differentially expressed protein-expressing genes (forkhead box protein O4 (FOXO4), interferon regulatory factor 8 (IRF8), and lymphoid enhancer binding factor 1 (LEF1)). Immunohistochemistry (IHC) and H-scoring provided semi-quantitative assessment of nuclear and cytoplasmic staining alongside qualitative data to contextualise staining (n = 26 patients). FOXO4 was expressed predominantly in the cytoplasm with significantly lower nuclear H-scores. IRF8 H-scores ranged from 0 to 3 throughout the cohort in the nucleus and cytoplasm. LEF1 was expressed in all patients with significantly lower cytoplasmic staining compared to nuclear. No sex or anatomical location differences were observed. While reduced levels of FOXO4 might indicate malignancy, the weak or absent protein expression limits its primary use as diagnostic tumour marker. IRF8 and LEF1 have more potential for prognostic and diagnostic uses and facilitate further understanding of their roles within their respective molecular pathways, including Wnt/beta-catenin/LEF1 signalling and differential regulation of tumour suppressor genes. Deeper understanding of the mechanisms involved in OSA are essential contributions towards the development of novel diagnostic, prognostic, and treatment options in human and veterinary medicine contexts.

Forkhead box O proteins: steering the course of stem cell fate

Stem cells are pivotal players in the intricate dance of embryonic development, tissue maintenance, and regeneration. Their behavior is delicately balanced between maintaining their pluripotency and differentiating as needed. Disruptions in this balance can lead to a spectrum of diseases, underscoring the importance of unraveling the complex molecular mechanisms that govern stem cell fate. Forkhead box O (FOXO) proteins, a family of transcription factors, are at the heart of this intricate regulation, influencing a myriad of cellular processes such as survival, metabolism, and DNA repair. Their multifaceted role in steering the destiny of stem cells is evident, as they wield influence over self-renewal, quiescence, and lineage-specific differentiation in both embryonic and adult stem cells. This review delves into the structural and regulatory intricacies of FOXO transcription factors, shedding light on their pivotal roles in shaping the fate of stem cells. By providing insights into the specific functions of FOXO in determining stem cell fate, this review aims to pave the way for targeted interventions that could modulate stem cell behavior and potentially revolutionize the treatment and prevention of diseases.

MicroRNAs as master regulators of FOXO transcription factors in cancer management

MicroRNAs are critical regulators of the plethora of genes, including FOXO "forkhead" dependent transcription factors, which are bonafide tumour suppressors. The FOXO family members modulate a hub of cellular processes like apoptosis, cell cycle arrest, differentiation, ROS detoxification, and longevity. Aberrant expression of FOXOs in human cancers has been observed due to their down-regulation by diverse microRNAs, which are predominantly involved in tumour initiation, chemo-resistance and tumour progression. Chemo-resistance is a major obstacle in cancer treatment. Over 90% of casualties in cancer patients are reportedly associated with chemo-resistance. Here, we have primarily discussed the structure, functions of FOXO and also their post-translational modifications which influence the activities of these FOXO family members. Further, we have addressed the role of microRNAs in carcinogenesis by regulating the FOXOs at post-transcriptional level. Therefore, microRNAs-FOXO axis can be exploited as a novel cancer therapy. The administration of microRNA-based cancer therapy is likely to be beneficial to curb chemo-resistance in cancers.

Role of Forkhead Box O Proteins in Hepatocellular Carcinoma Biology and Progression (Review)

Hepatocellular carcinoma (HCC), the most common type of malignant tumor of the digestive system, is associated with high morbidity and mortality. The main treatment for HCC is surgical resection. Advanced disease, recurrence, and metastasis are the main factors affecting prognosis. Chemotherapy and radiotherapy are not sufficiently efficacious for the treatment of primary and metastatic HCC; therefore, optimizing targeted therapy is essential for improving outcomes. Forkhead box O (FOXO) proteins are widely expressed in cells and function to integrate a variety of growth factors, oxidative stress signals, and other stimulatory signals, thereby inducing the specific expression of downstream signal factors and regulation of the cell cycle, senescence, apoptosis, oxidative stress, HCC development, and chemotherapy sensitivity. Accordingly, FOXO proteins are considered multifunctional targets of cancer treatment. The current review discusses the roles of FOXO proteins, particularly FOXO1, FOXO3, FOXO4, and FOXO6, in HCC and establishes a theoretical basis for the potential targeted therapy of HCC.

FOXO4 Transactivation Domain Interaction with Forkhead DNA Binding Domain and Effect on Selective DNA Recognition for Transcription Initiation

Forkhead box O4 (FOXO4) is a human transcription factor (TF) that participates in cell homeostasis. While the structure and DNA binding properties of the conserved forkhead domain (FHD) have been thoroughly investigated, how the transactivation domain (TAD) regulates the DNA binding properties of the protein remains elusive. Here, we investigated the role of TAD in modulating the DNA binding properties of FOXO4 using solution NMR. We found that TAD and FHD form an intramolecular complex mainly governed by hydrophobic interaction. Remarkably, TAD and DNA share the same surface of FHD for binding. While FHD did not differentiate binding to target and non-target DNA, the FHD-TAD complex showed different behaviors depending on the DNA sequence. In the presence of TAD, free and DNA-bound FHD exhibited a slow exchange with target DNA and a fast exchange with non-target DNA. The interaction of the two domains affected the kinetic function of FHD depending on the type of DNA. Based on these findings, we suggest a transcription initiation model by which TAD modulates FOXO4 recognition of its target promoter DNA sequences. This study describes the function of TAD in FOXO4 and provides a new kinetic perspective on target sequence selection by TFs.

Current perspective on the regulation of FOXO4 and its role in disease progression

Forkhead box O4 (FOXO4) is a member of the FOXO family that regulates a number of genes involved in metabolism, cell cycle, apoptosis, and cellular homeostasis via transcriptional activity. It also mediates cell responses to oxidative stress and treatment with antitumor agents. The expression of FOXO4 is repressed by microRNAs in multiple cancer cells, while FOXO4 function is regulated by post-translational modifications and interaction with other proteins. The deregulation of FOXO4 is closely linked to the progression of several types of cancer, senescence, and other diseases. In this review, we present recent findings on the regulation of FOXO4 in physiological and pathological conditions and provide an overview of the complex role of FOXO4 in disease development and response to therapy.

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.

MicroRNA-664 suppresses the growth of cervical cancer cells via targeting c-Kit

Background

Cervical cancer is the second most common malignant cancer in women worldwide. Evidence indicated that miR-664 was significantly downregulated in cervical cancer. However, the mechanisms by which miR-664 regulates the tumorigenesis of cervical cancer remain unclear. Thus, this study aimed to investigate the role of miR-664 in cervical cancer.

Methods

Quantitative reverse transcription polymerase chain reaction was used to detect the level of miR-664 in tumor tissues and cell line. The dual luciferase reporter system assay and Western blotting were used to explore the interaction of miR-664 and c-Kit in cervical cancer.

Results

The expression of miR-664 in patients with cervical cancer was dramatically decreased compared with that in adjacent tissues. MiR-664 mimics significantly inhibited proliferation in SiHa cells via inducing apoptosis. In addition, miR-664 mimics induced apoptosis in SiHa cells via increasing the expressions of Bax and active caspase 3 and decreasing the level of Bcl-2. Moreover, dual-luciferase assay showed that c-Kit was the directly binding target of miR-664 in SiHa cells; overexpression of miR-664 downregulated the expression of c-Kit. Meanwhile, upregulation of miR-664 significantly decreased the levels of c-Myc and Cyclin D in cells. Furthermore, miR-664 markedly inhibited tumor growth of cervical cancer in xenograft.

Conclusion

Our data indicated that miR-664 exerted antitumor effects on SiHa cells by directly targeting c-Kit in vitro and in vivo. Therefore, miR-664 might be a potential therapeutic target for the treatment of patients with cervical cancer.

Upregulation of miR‑95-3p inhibits growth of osteosarcoma by targeting HDGF

Osteosarcoma is the most common bone malignancy and miR-95-3p plays an important role in multiple cancers. The purpose of this study was to explore the effect and potential mechanism of miR-95-3p on the growth of osteosarcoma. In vitro, the osteosarcoma cell lines, SAOS-2 and U2OS cells, were transfected with miR-95-agomir to assess the role of miR-95-3p in proliferation and apoptosis of osteosarcoma cells. We determined that overexpression of miR-95-3p significantly attenuated cell proliferation but enhanced apoptosis in SAOS-2 and U2OS cells. We also found that overexpression of miR-95-3p in osteosarcoma cells downregulated the expression of hepatoma-derived growth factor (HDGF). Next, knockdown of HDGF by siRNA targeting HDGF clearly inhibited cell proliferation and induced apoptosis in U2OS cells. In vivo, a tumor formation assay in BALB/c nude mice was conducted by injecting the pre-miR-95 or control vector lentivirus-infected U2OS cells to determine the effect of miR-95-3p on the growth of osteosarcoma. Results showed miR-95-3p overexpression inhibited the osteosarcoma growth and downregulated the HDGF expression in xenografted tumor. For mechanism study, we co-transfected HDGF/pcDNA3.1 plasmid and miR-95-agomir to U2OS cells, and we demonstrated that overexpression of HDGF could attenuate the effects of miR-95-3p on U2OS cell proliferation, apoptosis and migration. These findings indicated that miR-95-3p might act as a potential tumor suppressor in osteosarcoma by targeting HDGF. Thus, miR-95-3p may become a potential therapeutic in treatment of osteosarcoma.

Upregulation of microRNA-7 contributes to inhibition of the growth and metastasis of osteosarcoma cells through the inhibition of IGF1R

We aim to uncover the methylation of microRNA-7 (miR-7) promoter in osteosarcoma (OS) and the inner mechanism of miR-7 on the progression of OS cells. Expression and methylation state of miR-7 in OS tissues and cells were detected. With the aim to unearth the ability of miR-7 in OS, the proliferation, cell cycle progression, apoptosis, invasion, migration of OS cells, and the tumor growth in nude mice were determined. Meanwhile, IGF1R expression was detected and the association between miR-7 and IGF1R was confirmed. The proliferating cell nuclear antigen (PCNA) expression was tested by immunohistochemical staining, and the lung metastasis was observed by H&E staining. miR-7 expression was decreased and methylation state of miR-7 was increased in OS tissues and cells. Upregulated miR-7 inhibited proliferation, cell cycle progression, invasion,and migration, while inducing apoptosis of OS cells and the tumor growth as well as PCNA expression in nude mice. Expression of IGF1R was downregulated in OS cells with overexpression of miR-7. Experiments verified the binding site between miR-7 and IGF1R. Our study demonstrates that abnormal methylation of miR-7 contributes to decreased miR-7 in OS. In addition, miR-7 represses the initiation and progression of OS cells through the inhibition of IGF1R.

Overexpression of miR-664 is associated with poor overall survival and accelerates cell proliferation, migration and invasion in hepatocellular carcinoma

Introduction

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. This study aimed to investigate the expression patterns of microRNA-664 (miR-664) in HCC tissues and cells, and assess its clinical significance and functional role in HCC.

Patients and methods

One hundred and thirty-four paired HCC and non-cancerous tissues were collected from patients who underwent surgery in Qianfoshan Hospital affiliated to Shandong University (Shandong, China) between 2009 and 2012. Expression of miR-664 was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Prognostic value of miR-664 in HCC was evaluated using Kaplan–Meier survival analysis and Cox regression analysis. Cell proliferation was analyzed using the CCK-8 assay, and cell migration and invasion of HCC cells was evaluated by the Transwell assay.

Results

Expression of miR-664 was significantly upregulated in HCC tissues and cells when compared with the normal controls (all P<0.05). MiR-664 expression was associated with lymph node metastasis, TNM stage and differentiation (all P<0.05) in the HCC patients. High miR-664 expression predicted poor overall survival (log-rank P=0.004) and acted as an independent prognostic factor (HR =1.945, 95% CI=1.078–3.508, P=0.027). According to cell experiments, the upregulation of miR-664 could promote, whereas the downregulation of miR-664 could inhibit proliferation, migration and invasion of HCC cells (all P<0.05). SIVA1 was predicted as a direct target gene of miR-664 in HCC.

Conclusion

All data indicated that overexpression of miR-664 is associated with poor prognosis of HCC patients, and may enhance tumor progression of HCC by targeting SIVA1. MiR-664 may be a candidate therapeutic target for HCC treatment.

MicroRNA-664 targets paired box protein 6 to inhibit the oncogenicity of pancreatic ductal adenocarcinoma

The abnormal expression of microRNAs (miRNAs or miRs) with oncogenic or tumor‑suppressive roles in pancreatic ductal adenocarcinoma (PDAC) has been widely reported in recent years, and these dysregulated miRNAs are implicated in the formation and progression of PDAC. Therefore, an investigation into the functional roles of miRNAs in PDAC may facilitate the identification of effective therapeutic targets. miRNA‑664 (miR‑664) has been found to be aberrantly expressed and to play crucial roles in several human cancer types. However, the expression pattern and functional roles of miR‑664 in the malignant capacity of PDAC have yet to be elucidated. In this study, the results revealed that miR‑664 was clearly downregulated in PDAC tissues and cell lines. The low miR‑664 expression was strongly associated with pathological T stage and lymph node metastasis of the patients with PDAC. Patients with PDAC with a low miR‑664 expression had a poorer overall survival and a worse disease‑free survival than those patients with a high miR‑664 level. Functional experiments suggested that exogenous miR‑664 expression suppressed the growth and metastasis of PDAC cells in vitro, whereas miR‑664 downregulation exerted the opposite effects. In addition, miR‑664 suppressed the tumor growth of PDAC cells in vivo. Mechanistically, paired box protein 6 (PAX6) was identified as a direct target gene of miR‑664 in PDAC cells. Furthermore, PAX6 was upregulated in PDAC tissues, and its upregulation inversely correlated with miR‑664 levels. Moreover, the silencing of PAX6 mimicked the effects of miR‑664 upregulation in PDAC cells, and the recovered expression of PAX6 eliminated the effects of miR‑664 on PDAC cells. Notably, miR‑664 could inhibit the activation of PI3K/Akt pathway in PDAC cells in vitro and in vivo. Cumulatively, these results indicate an important role of the miR‑664/PAX6 pathway in suppressing the aggressiveness of PDAC cells, suggesting that miR‑664 may be an attractive therapeutic target for the treatment of patients with this fatal disease.

Forkhead box O4 transcription factor in human neoplasms: Cannot afford to lose the novel suppressor

Forkhead box O4 (FOXO4), a member of FOXO family, has been highlighted as an essential transcriptional regulator in many diverse carcinomas. Accumulated studies have demonstrated that FOXO4 is downregulated and associated with tumorigenesis, invasiveness, and metastasis of most human cancer. FOXO4 alteration is also closely linked to the prognosis of various types of cancer. The aim of this review is to comprehensively present the clinical and pathological significance of FOXO4 in human cancer. Additionally, the potential clinical applications of future FOXO4 research are discussed. Collectively, the information reviewed here should increase the potential of FOXO4 as a therapeutic target for cancer.

MicroRNA-664-5p promotes myoblast proliferation and inhibits myoblast differentiation by targeting serum response factor and Wnt1

MicroRNAs (miRNAs) are noncoding RNAs that regulate gene expression at the post-transcriptional level and are involved in the regulation of the formation, maintenance, and function of skeletal muscle. Using miRNA sequencing and bioinformatics analysis, we previously found that the miRNA miR-664-5p is significantly differentially expressed in longissimus dorsi muscles of Rongchang pigs. However, the molecular mechanism by which miR-664-5p regulates myogenesis remains unclear. In this study, using flow cytometry, 5-ethynyl-2'-deoxyuridine staining, and cell count and immunofluorescent assays, we found that cell-transfected miR-664-5p mimics greatly promoted proliferation of C2C12 mouse myoblasts by increasing the proportion of cells in the S- and G₂-phases and up-regulating the expression of cell cycle genes. Moreover, miR-664-5p inhibited myoblast differentiation by down-regulating myogenic gene expression. In contrast, miR-664-5p inhibitor repressed myoblast proliferation and promoted myoblast differentiation. Mechanistically, using dual-luciferase reporter gene experiments, we demonstrated that miR-664-5p directly targets the 3'-UTR of serum response factor (SRF) and Wnt1 mRNAs. We also observed that miR-664-5p inhibits both mRNA and protein levels of SRF and Wnt1 during myoblast proliferation and myogenic differentiation, respectively. Furthermore, the activating effect of miR-664-5p on myoblast proliferation was attenuated by SRF overexpression, and miR-664-5p repressed myogenic differentiation by diminishing the accumulation of nuclear β-catenin. Of note, miR-664-5p's inhibitory effect on myogenic differentiation was abrogated by treatment with Wnt1 protein, the key activator of the Wnt/β-catenin signaling pathway. Collectively, our findings suggest that miR-664-5p controls SRF and canonical Wnt/β-catenin signaling pathways in myogenesis.

Identification of the miRNA-mRNA regulatory network of small cell osteosarcoma based on RNA-seq

Small cell osteosarcoma (SCO) is a rare subtype of osteosarcoma characterized by highly aggressive progression and a poor prognosis. The miRNA and mRNA expression profiles of peripheral blood mononuclear cells (PBMCs) were obtained in 3 patients with SCO and 10 healthy individuals using high-throughput RNA-sequencing. We identified 37 dysregulated miRNAs and 1636 dysregulated mRNAs in patients with SCO compared to the healthy controls. Specifically, the 37 dysregulated miRNAs consisted of 27 up-regulated miRNAs and 10 down-regulated miRNAs; the 1636 dysregulated mRNAs consisted of 555 up-regulated mRNAs and 1081 down-regulated mRNAs. The target-genes of miRNAs were predicted, and 1334 negative correlations between miRNAs and mRNAs were used to construct an miRNA-mRNA regulatory network. Dysregulated genes were significantly enriched in pathways related to cancer, mTOR signaling and cell cycle signaling. Specifically, hsa-miR-26b-5p, hsa-miR-221-3p and hsa-miR-125b-2-3p were significantly dysregulated miRNAs and exhibited a high degree of connectivity with target genes. Overall, the expression of dysregulated genes in tumor tissues and peripheral blood samples of patients with SCO measured by quantitative real-time polymerase chain reaction corroborated with our bioinformatics analyses based on the expression profiles of PBMCs from patients with SCO. Thus, hsa-miR-26b-5p, hsa-miR-221-3p and hsa-miR-125b-2-3p may be involved in SCO tumorigenesis.

MicroRNA-664 Targets Insulin Receptor Substrate 1 to Suppress Cell Proliferation and Invasion in Breast Cancer

A large number of microRNAs (miRNAs) have been previously demonstrated to be dysregulated in breast cancer (BC), and alterations in miRNA expression may affect the initiation and progression of BC. This study showed that miR-664 expression was obviously reduced in BC tissues and cell lines. Resumption of the expression of miR-664 attenuated the proliferation and invasion of BC cells. The molecular mechanisms underlying the inhibitory effects of BC cell proliferation and invasion by miR-664 were also studied. Insulin receptor substrate 1 (IRS1) was identified as a novel and direct target of miR-664. In addition, siRNA-mediated silencing of IRS1 expression mimicked the suppressive effects of miR-664 overexpression in BC cells. Rescue experiments demonstrated that recovered IRS1 expression partially antagonized the inhibition of proliferation and invasion of BC cells caused by miR-664 overexpression. Thus, miR-664 may serve as a tumor suppressor in BC by directly targeting IRS1. Moreover, miR-664 downregulation in BC may contribute to the occurrence and development of BC, suggesting that miR-664 may be a novel therapeutic target for patients with BC.

MicroRNA-520b Suppresses Proliferation, Migration, and Invasion of Spinal Osteosarcoma Cells via Downregulation of Frizzled-8

Spinal osteosarcoma (OS) is a malignant tumor that has a poor outcome. MicroRNA-520b (miR-520b) acts as a cancer suppressor in various types of cancer. Because of the limited amount of literature on OS, we aimed to identify the role of miR-520b in OS. The miR-520b level in clinical spinal OS tissues and adjacent nontumor tissues as well as in cell lines was assessed. The effect of miR-520b on cell proliferation, migration, invasion, and frizzled-8 (FZD8) degradation were all evaluated. Alterations of key proteins involved in the Wnt/β-catenin pathway were assessed by Western blot analysis. In the present study, miR-520b was downregulated in human spinal OS tissues and OS cell lines (p < 0.01 or p < 0.001). Overexpression of miR-520b inhibited cell proliferation (p < 0.01 or p < 0.001), migration (p < 0.01), and invasion (p < 0.01). FZD8 expression was negatively regulated by infection with a lentivirus vector carrying an miR-520b precursor in dose- and time-dependent manners. In OS tissues, miR-520b was inversely correlated with FZD8 expression. FZD8 was upregulated in human spinal OS tissues and cell lines. Finally, miR-520b inactivated the Wnt/β-catenin pathway through downregulation of FZD8. miR-520b inhibited cell proliferation, migration, and invasion through inactivating the Wnt/β-catenin pathway by downregulation of FZD8, providing a novel therapeutic target for spinal OS.

Genome-wide miRNA response to anacardic acid in breast cancer cells

MicroRNAs are biomarkers and potential therapeutic targets for breast cancer. Anacardic acid (AnAc) is a dietary phenolic lipid that inhibits both MCF-7 estrogen receptor α (ERα) positive and MDA-MB-231 triple negative breast cancer (TNBC) cell proliferation with IC50s of 13.5 and 35 μM, respectively. To identify potential mediators of AnAc action in breast cancer, we profiled the genome-wide microRNA transcriptome (microRNAome) in these two cell lines altered by the AnAc 24:1n5 congener. Whole genome expression profiling (RNA-seq) and subsequent network analysis in MetaCore Gene Ontology (GO) algorithm was used to characterize the biological pathways altered by AnAc. In MCF-7 cells, 69 AnAc-responsive miRNAs were identified, e.g., increased let-7a and reduced miR-584. Fewer, i.e., 37 AnAc-responsive miRNAs were identified in MDA-MB-231 cells, e.g., decreased miR-23b and increased miR-1257. Only two miRNAs were increased by AnAc in both cell lines: miR-612 and miR-20b; however, opposite miRNA arm preference was noted: miR-20b-3p and miR-20b-5p were upregulated in MCF-7 and MDA-MB-231, respectively. miR-20b-5p target EFNB2 transcript levels were reduced by AnAc in MDA-MB-231 cells. AnAc reduced miR-378g that targets VIM (vimentin) and VIM mRNA transcript expression was increased in AnAc-treated MCF-7 cells, suggesting a reciprocal relationship. The top three enriched GO terms for AnAc-treated MCF-7 cells were B cell receptor signaling pathway and ribosomal large subunit biogenesis and S-adenosylmethionine metabolic process for AnAc-treated MDA-MB-231 cells. The pathways modulated by these AnAc-regulated miRNAs suggest that key nodal molecules, e.g., Cyclin D1, MYC, c-FOS, PPARγ, and SIN3, are targets of AnAc activity.

Posttranscriptional regulation of FOXO expression: microRNAs and beyond

Forkhead box, class O (FOXO) transcription factors are major regulators of diverse cellular processes, including fuel metabolism, oxidative stress response and redox signalling, cell cycle progression and apoptosis. Their activities are controlled by multiple posttranslational modifications and nuclear-cytoplasmic shuttling. Recently, post-transcriptional regulation of FOXO synthesis has emerged as a new regulatory level of their functions. Accumulating evidence suggests that this post-transcriptional mode of regulation of FOXO activity operates in response to stressful stimuli, including oxidative stress. Here, we give a brief overview on post-transcriptional regulation of FOXO synthesis by microRNAs (miRNAs) and by RNA-binding regulatory proteins, human antigen R (HuR) and quaking (QKI). Aberrant post-transcriptional regulation of FOXOs is frequently connected with various disease states. We therefore discuss characteristic examples of FOXO regulation at the post-transcriptional level under various physiological and pathophysiological conditions, including oxidative stress and cancer. The picture emerging from this summary points to a diversity of interactions between miRNAs/miRNA-induced silencing complexes and RNA-binding regulatory proteins. Better insight into these complexities of post-transcriptional regulatory interactions will add to our understanding of the mechanisms of pathological processes and the role of FOXO proteins.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

MicroRNA-379 inhibits the proliferation, migration and invasion of human osteosarcoma cells by targetting EIF4G2

Osteosarcoma (OS) is an aggressive malignant mesenchymal neoplasm amongst adolescents. The aim of the present study was to explore the various modes of action that miR-379 has on the proliferation, migration, and invasion of human OS cells. miR-379 achieves this by targetting eukaryotic initiation factor 4GII (EIF4G2). Human OS cell lines U2OS and MG-63 were selected and assigned into blank, miR-379 mimics, miR-379 mimic negative control (NC), miR-379 inhibitors, miR-379 inhibitor NC, EIF4G2 shRNA, control shRNA, and miR-379 inhibitor + EIF4G2 shRNA group. The miR-379 expression and EIF4G2 mRNA expression were detected utilising quantitative real-time PCR (qRT-PCR) and the EIF4G2 protein expression using Western blotting. MTT assay, scratch test, Transwell assay, and flow cytometry were performed to determine the proliferation, migration, invasion, and cell cycle, respectively. In comparison with the miR-379 mimic NC group, the miR-379 mimics group had decreased EIF4G2 expression; the miR-379 inhibitors group indicated an increased EIF4G2 expression. Compared with the control shRNA group, the EIF4G2 expression was lower in the EIF4G2 shRNA group and the miR-379 expression was dropped in the miR-379 inhibitor + EIF4G2 shRNA group. The proliferation, migration, and invasion abilities of OS cells were reduced in the miR-379 mimics and EIF4G2 shRNA groups. The percentage of OS cells at the G₀/G₁ stage was increased, and the percentage at the S-stage was decreased in the miR-379 mimics and EIF4G2 shRNA groups. miR-379 may inhibit the proliferation, migration and invasion of OS cells through the down-regulation of EIF4G2.

Down-regulated miR-26a promotes proliferation, migration, and invasion via negative regulation of MTDH in esophageal squamous cell carcinoma

Numerous studies have reported that the role played by miR-26a in cancer is controversial, but whether miR-26a regulates metadherin (MTDH) expression in esophageal squamous cell carcinoma (ESCC) is unclear. We performed this study to investigate the clinical relevance of miR-26a expression in ESCC. miR-26a was detected by using the in situ hybridization method. To functionally analyze the role of miR-26a in ESCC cell lines in vitro, KYSE-450 and Eca109 cells were employed, whose endogenous miR-26a was artificially down- or up-regulated, respectively, by using lentiviral-based transfection. There was significant association between miR-26a expression and clinical stage (P = 0.049), lymph node metastasis (P = 0.023), tumor volume (P = 0.003), and poor overall prognosis (P = 0.026). miR-26a was able to suppress proliferation and migration of ESCC cells in vitro Moreover, we have confirmed that miR-26a can negatively regulate MTDH in ESCC cells by using luciferase reporter assay. In addition, to investigate the role miR-26a plays in cell proliferation, we nude mice were xenografted with ESCC cells whose miR-26a was stably down- and up-regulated. Together, our results show that miR-26a is capable of suppressing the proliferation and migration of ESCC cells via negative regulation of MTDH. Moreover, miR-26a expression was clinically relevant in cancer progression and poor prognosis, which supports the idea that miR-26a acts as a tumor suppressor in ESCC.-Yang, C., Zheng, S., Liu, T., Liu, Q., Dai, F., Zhou, J., Chen, Y., Sheyhidin, I., Lu, X. Down-regulated miR-26a promotes proliferation, migration, and invasion via negative regulation of MTDH in esophageal squamous cell carcinoma.