IGF1 3'UTR functions as a ceRNA in promoting angiogenesis by sponging miR-29 family in osteosarcoma

Interactive role of miR-29, miR-93, miR-205, and VEGF in salivary adenoid cystic carcinoma

OBJECTIVES

Salivary adenoid cystic carcinoma (SACC) is one of the most common salivary gland tumors in which patients encounter local recurrence and lung metastases. Understanding prognostic biomarkers in SACC is essential for future development in prognosis and treatment. This study aimed to assess the expression level of vascular endothelial growth factor (VEGF) and its potential regulatory microRNAs in SACC for prognostic determination. MATERIAL AND METHODS: The expression of VEGF in SACC samples was assessed using immunohistochemistry. Potential regulatory microRNAs were evaluated using quantitative reverse transcription-polymerase chain reaction. Associations between VEGF and microRNAs expression and clinicopathological parameters were investigated.

RESULTS

VEGF expression levels positively correlated with histologic grade (p = .004) and treatment modality (p = .04). Decreased expression of miR-29a (p = .01) and increased expression of miR-93-5p and miR-205 (both p < .0001) were observed in SACC compared to normal salivary gland tissue. MiR-93-5p showed a positive association (p = .02) with VEGF overexpression.

CONCLUSIONS

Our results showed the downregulation of miR-29 and overexpression of miR-93 and miR-205 in the SACC group, and the correlation between miR-93 and VEGF suggests these biomarkers as potential prognostic markers in the future.

Non-coding RNAs as potential biomarkers in osteosarcoma

Osteosarcoma (OS) is a primary solid malignant tumor that occurs most frequently in the metaphysis of long bones. More likely to happen to children and adolescents. OS has high mortality and disability rate. However, the etiology and pathogenesis of OS have not been fully understood till now. Due to the lack of effective biomarkers, OS cannot be precisely detected in the early stage. With the application of next-generation and high-throughput sequencing, more and more abnormally expressed non-coding RNAs(ncRNAs) have been identified in OS. Growing evidences have suggested the ncRNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), have played an important role in the tumorigenesis and progression of OS. Thus, they can be served as novel biomarkers for diagnosis, treatment and prognosis. This review summarized the application of ncRNA as biomarkers in OS in detail, and discussed the limitation and future improvement of the potential biomarkers.

Gain of Chromosome 1q Perturbs a Competitive Endogenous RNA Network to Promote Melanoma Metastasis

Somatic copy-number alterations (CNA) promote cancer, but the underlying driver genes may not be comprehensively identified if only the functions of the encoded proteins are considered. mRNAs can act as competitive endogenous RNAs (ceRNA), which sponge miRNAs to posttranscriptionally regulate gene expression in a protein coding-independent manner. We investigated the contribution of ceRNAs to the oncogenic effects of CNAs. Chromosome 1q gains promoted melanoma progression and metastasis at least in part through overexpression of three mRNAs with ceRNA activity: CEP170, NUCKS1, and ZC3H11A. These ceRNAs enhanced melanoma metastasis by sequestering tumor suppressor miRNAs. Orthogonal genetic assays with miRNA inhibitors and target site blockers, along with rescue experiments, demonstrated that miRNA sequestration is critical for the oncogenic effects of CEP170, NUCKS1, and ZC3H11A mRNAs. Furthermore, chromosome 1q ceRNA-mediated miRNA sequestration alleviated the repression of several prometastatic target genes. This regulatory RNA network was evident in other cancer types, suggesting chromosome 1q ceRNA deregulation as a common driver of cancer progression. Taken together, this work demonstrates that ceRNAs mediate the oncogenicity of somatic CNAs.

SIGNIFICANCE

The function of CEP170, NUCKS1, and ZC3H11A mRNAs as competitive endogenous RNAs that sequester tumor suppressor microRNAs underlies the oncogenic activity of chromosome 1q gains.

miR-29a-3p mitigates the development of osteosarcoma through modulating IGF1 mediated PI3k/Akt/FOXO3 pathway by activating autophagy

Osteosarcoma (OS), occurring in mesenchymal tissues and with a high degree of malignancy, is most common in children and adolescents. At present, we intend to figure out the expression and functions of miR-29a-3p in OS development. Reverse transcription-polymerase chain reaction (RT-PCR) was adopted to monitor the expression of miR-29a-3p and IGF1 in OS tissues and adjacent non-tumor tissues. Then, the 3- (4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay, colony formation experiment, western blot and Transwell assay were conducted to validate OS cell proliferation, colony formation ability, apoptosis, migration and invasion. Next, the association between miR-29a-3p and IGF1 was corroborated by the dual-luciferase reporter assay and the Pearson correlation analysis. Finally, WB was implemented to test the levels of autophagy-related proteins LC3-I/LC3-II, Beclin-1, p62, and the IGF-1R/PI3k/Akt/FOXO3 axis in OS cells. As a result, miR-29a-3p was down-regulated in OS tissues (versus adjacent non-tumor tissues) and OS cell lines. Overexpressing miR-29a-3p aggravated apoptosis, dampened cell proliferation, colony formation, migration and invasion, and promoted autophagy of OS cells. IGF1 was identified as a target of miR-29a-3p. IGF1 induced oncogenic effects in OS by activating IGF-1R/ PI3k/Akt pathway, and it dampened the tumor-suppressive effect of miR-29a-3p on OS. Taken together, miR-29a-3p repressed the OS evolvement through inducing autophagy and inhibiting IGF1 mediated PI3k/Akt/FOXO3 pathway.

Circular RNA circFOXP1 promotes angiogenesis by regulating microRNA -127-5p/CDKN2AIP signaling pathway in osteosarcoma

Osteosarcoma is known to have a high metastatic potential, which is closely related to angiogenesis. circRNAs are closely associated with osteosarcoma metastasis. This study aims to investigate the role of Circular RNA circFOXP1 in angiogenesis in osteosarcoma. We detected circFOXP1 expression in osteosarcoma, as well as its prognostic value. Tube formation assay and immunohistochemistry staining were conducted to determine the condition of tube formation. RT-qPCR was performed to explore targeted genes. Luciferase reporter assays were carried out to explore the interaction between miR-127-5p, ircFOXP1, and CDKN2AIP, respectively. In vivo studies further confirmed the relationship between circFOXP1 and tumor angiogenesis in osteosarcoma. We found that circFOXP1 expression was increased in osteosarcoma, and could promote angiogenesis in osteosarcoma through upregulating CDKN2AIP expression. Moreover, circFOXP1 could directly bind to miR-127-5p, which further targets CDKN2AIP directly. In conclusion, circFOXP1 promoted angiogenesis by regulating miR-127-5p/CDKN2AIP signaling pathway in osteosarcoma.

TimiRGeN: R/Bioconductor package for time series microRNA-mRNA integration and analysis

Motivation

The analysis of longitudinal datasets and construction of gene regulatory networks (GRNs) provide a valuable means to disentangle the complexity of microRNA (miRNA)–mRNA interactions. However, there are no computational tools that can integrate, conduct functional analysis and generate detailed networks from longitudinal miRNA–mRNA datasets.

Results

We present TimiRGeN, an R package that uses time point-based differential expression results to identify miRNA–mRNA interactions influencing signaling pathways of interest. miRNA–mRNA interactions can be visualized in R or exported to PathVisio or Cytoscape. The output can be used for hypothesis generation and directing in vitro or further in silico work such as GRN construction.

Availability and implementation

TimiRGeN is available for download on Bioconductor (https://bioconductor.org/packages/TimiRGeN) and requires R v4.0.2 or newer and BiocManager v3.12 or newer.

Supplementary information

Supplementary data are available at Bioinformatics online.

Role of microRNAs in the crosstalk between osteosarcoma cells and the tumour microenvironment

Osteosarcoma (OS) is the most common primary bone tumour, with a peak incidence in adolescents, and the five-year survival rate of patients with metastasis or recurrence is much lower than that of patients without metastasis and recurrence. OS is initiated and develops in a complex tumour microenvironment (TME) that contains many different components, such as osteoblasts, osteoclasts, mesenchymal stem cells, fibroblasts, immune cells, extracellular matrix (ECM), extracellular vesicles, and cytokines. The extensive interaction between OS and the TME underlies OS progression. Therefore, rather than targeting OS cells, targeting the key factors in the TME may yield novel therapeutic approaches. MicroRNAs (miRNAs) play multiple roles in the biological behaviours of OS, and recent studies have implied that miRNAs are involved in mediating the communication between OS cells and the surrounding TME. Here, we review the TME landscape and the miRNA dysregulation of OS, describe the role of the altered TME in OS development and highlight the role of miRNA in the crosstalk between OS cells and the TME.

LncRNA CCAL Promotes Angiogenesis Through Regulating the MiR-29b/ANGPTL4 Axis in Osteosarcoma

Purpose

The objective of this study was to detect the expression of the long noncoding RNA (lncRNA) colorectal cancer-associated lncRNA (CCAL) in osteosarcoma tissues and to investigate its role in angiogenesis and the potential molecular mechanisms associated with this effect in osteosarcoma.

Materials and Methods

CCAL expression in 40 osteosarcoma tissues and 40 noncancerous tissues was measured by qRT-PCR (quantitative real-time polymerase chain reaction). Tube formation assays were performed to explore the role of CCAL in angiogenesis in osteosarcoma. In addition, the regulatory interaction between CCAL, miR-29b, and ANGPTL4 was investigated via luciferase reporter assay and bioinformatics predictive analysis.

Results

Compared with noncancerous tissues, the expression of CCAL was markedly upregulated in osteosarcoma tissues. Higher CCAL expression levels were closely related to shorter overall survival in patients with osteosarcoma. Additionally, functional analysis indicated that CCAL could facilitate tumour angiogenesis in vitro and in vivo in osteosarcoma. Mechanistically, CCAL upregulated ANGPTL4 expression in osteosarcoma cells, and ANGPTL4 mediated angiogenic induction by CCAL in osteosarcoma. Moreover, CCAL directly targeted miR-29b in osteosarcoma. More importantly, we demonstrated that CCAL upregulated the expression of ANGPTL4 by sponging miR-29b, which promoted angiogenesis in osteosarcoma.

Conclusion

Our results show that CCAL promotes angiogenesis by regulating the miR-29b/ANGPTL4 axis in osteosarcoma.

MicroRNA-mRNA Co-sequencing Identifies Transcriptional and Post-transcriptional Regulatory Networks Underlying Muscle Wasting in Cancer Cachexia

Cancer cachexia is a metabolic syndrome with alterations in gene regulatory networks that consequently lead to skeletal muscle wasting. Integrating microRNAs-mRNAs omics profiles offers an opportunity to understand transcriptional and post-transcriptional regulatory networks underlying muscle wasting. Here, we used RNA sequencing to simultaneously integrate and explore microRNAs and mRNAs expression profiles in the tibialis anterior (TA) muscles of the Lewis Lung Carcinoma (LLC) model of cancer cachexia. We found 1,008 mRNAs and 18 microRNAs differentially expressed in cachectic mice compared with controls. Although our transcriptomic analysis demonstrated a high heterogeneity in mRNA profiles of cachectic mice, we identified a reduced number of differentially expressed genes that were uniformly regulated within cachectic muscles. This set of uniformly regulated genes is associated with the extracellular matrix (ECM), proteolysis, and inflammatory response. We also used transcriptomic data to perform enrichment analysis of transcriptional factor binding sites in promoter sequences, which revealed activation of the atrophy-related transcription factors NF-κB, Stat3, AP-1, and FoxO. Furthermore, the integration of mRNA and microRNA expression profiles identified post-transcriptional regulation by microRNAs of genes involved in ECM organization, cell migration, transcription factors binding, ion transport, and the FoxO signaling pathway. Our integrative analysis of microRNA-mRNA co-profiles comprehensively characterized regulatory relationships of molecular pathways and revealed microRNAs targeting ECM-associated genes in cancer cachexia.

CFIm25-regulated lncRNA acv3UTR promotes gastric tumorigenesis via miR-590-5p/YAP1 axis

Accumulating evidences indicate that 3ʹUTR of the coding gene can act as crucial regulators in gastric cancer (GC). However, the detailed mechanisms and responsive targets are not well established. Here, we found that acvr1b gene 3ʹUTR (acv3UTR) was elevated in GC tissue, the expression of which was significantly correlated with advanced pTNM-stage and poor outcome in clinical patients. Forced expression of acv3UTR promoted GC cells growth in vitro and in vivo. Mechanistically, our results suggested that acv3UTR functioned as an oncogenic competing endogenous RNA via sponging miR-590-5p and enhancing YAP1 level. Tumor suppressor miR-590-5p was a molecular module in acv3UTR regulatory axis, the forced expression of which led to impairing of oncogenic potential of acv3UTR. The positive correlation of acv3UTR and YAP1 expression, and the negative correlation of acv3UTR and miR-590-5p expression, were verified in GC patients. Moreover, CFIm25 was identified as a key regulator contributing to acv3UTR aberrant expression in GC binding to UGUA-264 motif. Overall, our finding defines a mechanism for understanding the potential role of acv3UTR transcription in GC tumorigenesis, and indicates a correlation between 3ʹUTR trans-regulatory effect and GC development.

Increased HERV-E clone 4-1 expression contributes to DNA hypomethylation and IL-17 release from CD4+ T cells via miR-302d/MBD2 in systemic lupus erythematosus

Background

Increased human endogenous retroviruses E clone 4–1 (HERV-E clone 4–1) mRNA expression is observed in systemic lupus erythematosus (SLE) patients and associates with the disease activity. In this study, we want to further investigate the mechanism of HERV-E clone 4–1 mRNA upregulation and its roles in SLE progression.

Methods

CD4⁺ T cells were isolated from venous blood of SLE patients or healthy controls and qRT-PCR was used to detect HERV-E clone 4–1 mRNA expression. We then investigated the regulation of Nuclear factor of activated T cells 1 (NFAT1) and Estrogen receptor-α (ER-α) on HERV-E clone 4–1 transcription and the functions of HERV-E clone 4–1 3′ long terminal repeat (LTR) on DNA hypomethylation and IL-17 release.

Results

We found HERV-E clone 4–1 mRNA expression was upregulated in CD4⁺ T cells from SLE patients and positively correlated with SLE disease activity. This is associated with the activation of Ca²⁺/calcineurin (CaN)/NFAT1 and E2/ER-α signaling pathway and DNA hypomethylation of HERV-E clone 4–1 5’LTR. HERV-E clone 4–1 also takes part in disease pathogenesis of SLE through miR-302d/Methyl-CpG binding domain protein 2 (MBD2)/DNA hypomethylation and IL-17 signaling via its 3’LTR.

Conclusions

HERV-E clone 4–1 mRNA upregulation is due to the abnormal inflammation/immune/methylation status of SLE and it could act as a potential biomarker for diagnosis of SLE. HERV-E clone 4–1 also takes part in disease pathogenesis of SLE via its 3’LTR and the signaling pathways it involved in may be potential therapeutic targets of SLE.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0416-5) contains supplementary material, which is available to authorized users.

BMP-2 and miR-29c in osteosarcoma tissues on proliferation and invasion of osteosarcoma cells

Expression of bone morphogenetic protein (BMP)-2 and microRNA (miR)-29c in osteosarcoma tissues and effects on proliferation and invasion of osteosarcoma cells were investigated. A retrospective analysis of 75 patients with osteosarcoma who underwent surgery in Tianjin Baodi Hospital from May 2013 to June 2017 was conducted. A total of 75 osteosarcoma tissues and 51 normal paraneoplastic tissues were collected. RT-PCR was used to compare the expression difference of BMP-2 and miR-29c. miR-29c mimics (experimental group A) and BMP-2 siRNA plasmid (experimental group B) were transfected into human osteosarcoma cells MG-63, respectively. The transfected cells were divided into miRNA negative control (miR-NC) group (cells transfected with miR-negative control), siRNA negative control group (cells transfected with non-silent siRNA) and blank group (cells without any transfection). MTT assay was used to detect cell proliferation in each group at different time periods. Transwell insert was used to detect invasion of cells in vitro. The relative expression of BMP-2 in osteosarcoma tissue was significantly higher than that in paraneoplastic tissue (P<0.05). Τhe relative expression of miR-29c in osteosarcoma tissue was significantly lower than that in paraneoplastic tissue (P<0.05). The cell survival rates in experimental groups A and B were significantly lower than those in the blank, miR-NC negative control and siRNA negative control groups on day 5 (P<0.05). The number of cell transmembranes in experimental groups A and B was significantly lower than those in the blank, miR-NC negative control and siRNA negative control groups (P<0.05). BMP-2 is over-expressed in osteosarcoma tissues, and miR-29c is under-expressed in osteosarcoma tissues. Interfering with the expression of BMP-2 and overexpression of miR-29c can inhibit the proliferation and invasion of osteosarcoma cells, indicating that BMP-2 and miR-29c may be involved in the regulation of proliferation and metastasis of osteosarcoma cells and could be used as new molecular target markers for the diagnosis and treatment of osteosarcoma.

A Systematic Review of miR-29 in Cancer

MicroRNAs (miRNA) are small non-coding RNAs (∼22 nt in length) that are known as potent master regulators of eukaryotic gene expression. miRNAs have been shown to play a critical role in cancer pathogenesis, and the misregulation of miRNAs is a well-known feature of cancer. In recent years, miR-29 has emerged as a critical miRNA in various cancers, and it has been shown to regulate multiple oncogenic processes, including epigenetics, proteostasis, metabolism, proliferation, apoptosis, metastasis, fibrosis, angiogenesis, and immunomodulation. Although miR-29 has been thoroughly documented as a tumor suppressor in the majority of studies, some controversy remains with conflicting reports of miR-29 as an oncogene. In this review, we provide a systematic overview of miR-29's functional role in various mechanisms of cancer and introspection on the contradictory roles of miR-29.

miR-29 Family Inhibits Resistance to Methotrexate and Promotes Cell Apoptosis by Targeting COL3A1 and MCL1 in Osteosarcoma

Background

MicroRNAs (miRNAs) play a crucial role in regulating diverse biological processes, including drug resistance. We investigated the potential roles of the miR-29 family in methotrexate (MTX) resistance in osteosarcoma.

Material/Methods

Two MTX-resistant osteosarcoma cell lines, MG-63/MTX and U2OS/MTX, were generated by continuous exposure to stepwise increasing concentrations of MTX. miR-29abc, COL3A1, and MCL1 mRNA expression levels were determined using quantitative real-time PCR (qRT-PCR). Protein expression levels of COL3A1 and MCL1 were detected by Western blot. Cell viability, IC50 value, and cell apoptosis were assessed by CCK-8 assay and flow cytometry, respectively. The target relationship between the miR-29 family and COL3A1 or MCL1 was confirmed by luciferase reporter assay.

Results

miR-29a, miR-29b, and miR-29c were significantly downregulated in MG-63/MTX and U2OS/MTX cells and in chemotherapy poor-response osteosarcoma tissues. Overexpression of the miR-29 family sensitized MG-63/MTX and U2OS/MTX cells to MTX and obviously promoted cell apoptosis compared with negative control. COL3A1 and MCL1 were identified to be target genes of the miR-29 family, and transfection with miR-29abc mimics in MG-63/MTX and U2OS/MTX cells decreased COL3A1 and MCL1 mRNA and protein expression. Meanwhile, overexpression of COL3A1 and MCL1 partly neutralized the effects of the miR-29 family on MTX resistance and cell apoptosis.

Conclusions

Taken together, our findings suggested a tumor-suppressor role of the miR-29 family in control of MTX resistance and cell apoptosis through regulating COL3A1 or MCL1. Targeting the miR-29 family might provide new strategies to overcome the high-dosage MTX-induced cytotoxicity in osteosarcoma treatment.

miR-29 promotes osteosarcoma cell proliferation and migration by targeting PTEN

Osteosarcoma (OS) is an aggressive malignant neoplasm that arises from primitively transformed cells of mesenchymal origin, and that exhibits osteoblastic differentiation and produces malignant osteoid. MicroRNAs (miRNAs) have been widely reported to have important regulatory roles in various human tumors, including OS. However, the potential mechanism of miR-29 in OS remains largely unknown. miR-29 was highly expressed in OS and overexpression of miR-29 promoted OS cell proliferation, as well as proliferating cell nuclear antigen (PCNA) expression and migration, whereas lower expression of miR-29 inhibited OS cell proliferation, PCNA expression and migration. In the present study, a dual-luciferase reporter system supporting phosphatase and tensin homolog (PTEN) was a target of miR-29 and its expression was inhibited by miR-29 mimic, but increased by miR-29 inhibitor. Overexpression of PTEN inhibited OS cell proliferation and migration and it could attenuate miR-29 promotion effect on OS progression. Overall, the results revealed that miR-29, as a tumor promoter, is involved in OS progression and metastasis by targeting PTEN, indicating that the miR-29/PTEN pathway is a potential therapeutic target for the treatment of OS.

Complexities of post-transcriptional regulation and the modeling of ceRNA crosstalk

Control of gene and protein expression is required for cellular homeostasis and is disrupted in disease. Following transcription, mRNA turnover and translation is modulated, most notably by microRNAs (miRNAs). This modulation is controlled by transcriptional and post-transcriptional events that alter the availability of miRNAs for target binding. Recent studies have proposed that some transcripts - termed competitive endogenous RNAs (ceRNAs) - sequester a miRNA and diminish its repressive effects on other transcripts. Such ceRNAs thus mutually alter each other's abundance by competing for binding to a common set of miRNAs. Some question the relevance of ceRNA crosstalk, arguing that an individual transcript, when its abundance lies within a physiological range of gene expression, will fail to compete for miRNA binding due to the high abundance of other miRNA binding sites across the transcriptome. Despite this, some experimental evidence is consistent with the ceRNA hypothesis. In this review, we draw upon existing data to highlight mechanistic and theoretical aspects of ceRNA crosstalk. Our intent is to propose how understanding of ceRNA crosstalk mechanisms can be improved and what evidence is required to demonstrate a ceRNA mechanism. A greater understanding of factors affecting ceRNA crosstalk should shed light on its relevance in physiological states.

Construction and analysis of a ceRNA‑ceRNA network reveals two potential prognostic modules regulated by hsa‑miR‑335‑5p in osteosarcoma

Osteosarcoma is an aggressive cancer of the skeletal system, which is associated with a poor prognosis due to the high recurrence rate. Although previous studies have revealed that competitive endogenous RNAs (ceRNAs) are involved in various biological processes in the physiology and development of osteosarcoma, the roles of ceRNAs in osteosarcoma recurrence remain largely unexplored. The present study constructed a ceRNA-ceRNA network for osteosarcoma by systematically integrating matched expression profiles for microRNAs (miRNAs/miRs) and mRNAs, and identified two ceRNA-mediated modules that were associated with recurrence in patients with osteosarcoma. A multivariate Cox regression analysis demonstrated that the recurrence-free prognosis associated with the expression of the two modules was independent of other clinical factors. In addition, hsa-miR-335-3p was identified as an upstream regulating factor for both modules. In conclusion, the results of the present study suggested that ceRNAs may act as potential therapeutic biomarkers for predicting the recurrence of osteosarcoma, and may help to identify patients with osteosarcoma at a high risk of recurrence, who may benefit from adjuvant therapy.

miRNA-mediated 'tug-of-war' model reveals ceRNA propensity of genes in cancers

Competing endogenous RNA (ceRNA) are transcripts that cross‐regulate each other at the post‐transcriptional level by competing for shared microRNA response elements (MREs). These have been implicated in various biological processes impacting cell‐fate decisions and diseases including cancer. There are several studies that predict possible ceRNA pairs by adopting various machine‐learning and mathematical approaches; however, there is no method that enables us to gauge as well as compare the propensity of the ceRNA of a gene and precisely envisages which among a pair exerts a stronger pull on the shared miRNA pool. In this study, we developed a method that uses the ‘tug of war of genes’ concept to predict and quantify ceRNA potential of a gene for the shared miRNA pool in cancers based on a score represented by SoCeR (score of competing endogenous RNA). The method was executed on the RNA‐Seq transcriptional profiles of genes and miRNA available at TCGA along with CLIP‐supported miRNA‐target sites to predict ceRNA in 32 cancer types which were validated with already reported cases. The proposed method can be used to determine the sequestering capability of the gene of interest as well as in ranking the probable ceRNA candidates of a gene. Finally, we developed standalone applications (SoCeR tool) to aid researchers in easier implementation of the method in analysing different data sets or diseases.

miR-29a regulated ER-positive breast cancer cell growth and invasion and is involved in the insulin signaling pathway

Increasing amounts of evidence show that insulin can activate different insulin signaling pathways to promote breast cancer growth and invasion. miR-29a plays crucial roles in decreasing glucose-stimulated insulin secretion, as well as in regulating breast cancer cell proliferation and EMT. However, the mechanism responsible for the regulatory effects of miR-29a on breast cancer growth and invasion and the relationship between these effects and insulin signaling remains unclear. Herein, we showed that human insulin increased miR-29a expression in ER-positive breast cancer cells and that miR-29a facilitated the ability of insulin to promote breast cancer cell proliferation and migration. We found that miR-29a-induced cell proliferation and metastasis acceleration occurred primarily through ERK phosphorylation. The IGF-1R is the upstream target gene of miR-29a, while CDC42 and p85α are the downstream target genes of miR-29a. These results have provided us with information regarding the molecular mechanisms by which hyperinsulinemia promotes breast cancer occurrence and development and thus leads to a poor prognosis in breast cancer patients and indicate that miR-29a plays an important role in breast cancer development and invasion.

Co-expression analysis revealed PTCH1-3'UTR promoted cell migration and invasion by activating miR-101-3p/SLC39A6 axis in non-small cell lung cancer: implicating the novel function of PTCH1

Metastasis is the most common cause of mortality for non-small cell lung cancer (NSCLC). PTCH1, a receptor of Hedgehog (Hh) pathway, is reported to suppress cell proliferation. Interestingly, our previous study showed PTCH1 silencing promoted cell proliferation but inhibited cell migration and invasion of NSCLC cells. However, the precise mechanisms of PTCH1 regulating NSCLC metastasis remain unclear. PTCH1 has multiple splicing variants, which all share the same 3'UTR sequence, meanwhile, emerging studies have shown competing endogenous RNAs (ceRNAs) play important roles in regulating cancer progression. Therefore, we hypothesized the functions of PTCH1-3'UTR in NSCLC in present study to reveal its role as a ceRNA. Here, we find overexpression of PTCH1-3'UTR promotes cell migration, invasion and adhesion, but does not affect cell proliferation in NSCLC cells. By combining weighted correlation network analysis (WGCNA) analysis and experimental validation, we reported PTCH1-3'UTR acted as a sponge to absorb miR-101-3p and promoted SLC39A6 expression. Moreover, we observed low expression of miR-101-3p and PTCH1 and high SLC39A6 levels were positively correlated with NSCLC progression. Therefore, our results help to understand the function of PTCH1 in NSCLC tumorigenesis and provide novel insights for the prevention of NSCLC metastasis.

Animal models for glucocorticoid-induced postmenopausal osteoporosis: An updated review

Glucocorticoid-induced postmenopausal osteoporosis is a severe osteoporosis, with high risk of major osteoporotic fractures. This severe osteoporosis urges more extensive and deeper basic study, in which suitable animal models are indispensable. However, no relevant review is available introducing this model systematically. Based on the recent studies on GI-PMOP, this brief review introduces the GI-PMOP animal model in terms of its establishment, evaluation of bone mass and discuss its molecular mechanism. Rat, rabbit and sheep with their respective merits were chosen. Both direct and indirect evaluation of bone mass help to understand the bone metabolism under different intervention. The crucial signaling pathways, miRNAs, osteogenic- or adipogenic- related factors and estrogen level may be the predominant contributors to the development of glucocorticoid-induced postmenopausal osteoporosis.

Endogenous microRNA sponges: evidence and controversy

The competitive endogenous RNA (ceRNA) hypothesis proposes that transcripts with shared microRNA (miRNA) binding sites compete for post-transcriptional control. This hypothesis has gained substantial attention as a unifying function for long non-coding RNAs, pseudogene transcripts and circular RNAs, as well as an alternative function for messenger RNAs. Empirical evidence supporting the hypothesis is accumulating but not without attracting scepticism. Recent studies that model transcriptome-wide binding-site abundance suggest that physiological changes in expression of most individual transcripts will not compromise miRNA activity. In this Review, we critically evaluate the evidence for and against the ceRNA hypothesis to assess the impact of endogenous miRNA-sponge interactions.