MicroRNA-873 (miRNA-873) inhibits glioblastoma tumorigenesis and metastasis by suppressing the expression of IGF2BP1

LncRNA UCA1 facilitated cell growth and invasion through the miR-206/CLOCK axis in glioma

Background

Glioma is a lethal malignant brain tumor, which affects the brain functions and is life-threatening. LncRNA UCA1 was identified as a pivotal regulator for tumorigenesis of glioma. MiR-206 was discovered to promote tumorigenesis and is critical in the regulation of cell proliferation in glioma. This study will discuss the expression of UCA1 regarding miR-206 and CLOCK, and their integrative effects in the proliferation and cell cycle of glioma cells.

Methods

qRT-PCR was conducted to measure the mRNA expressions of IgG and Ago2 in cells co-transfected with UCA1, and miR-216 in U251. Bioinformation was analyzed for the prediction of association between UCA1 and miR-206. Transwell migrations assays and invasion assays were utilized to observe the cell invasive ability. Western blot and immunofluorescence imaging were used to examine the protein expressions. In vivo comparisons and observations were also performed to investigate the role of UCA1 in glioma growth.

Results

LncRNA UCA1 was up-regulated in glioma cell lines and tissues. It elevated cell invasion via the inducing of epithelial-mesenchymal transition. We found that UCA1 can modulate miR-206 expression and serve as an endogenous sponge of miR-206. The EMT-inducer CLOCK was validated as a messenger RNA target of miR-206. At last, we demonstrated that UCA1 exerted the biology function through regulating miR-206 and CLOCK in vivo.

Conclusions

Overall, the results demonstrated that UCA1/miR-206/CLOCK axis participated in the progressing of glioma and could act as a promising therapeutic target.

Insulin-like growth factor 2 mRNA-binding protein 1 promotes cell proliferation via activation of AKT and is directly targeted by microRNA-494 in pancreatic cancer

BACKGROUND

Studies have shown that insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) plays critical roles in the genesis and development of human cancers.

AIM

To investigate the clinical significance and role of IGF2BP1 in pancreatic cancer.

METHODS

Expression levels of IGF2BP1 and microRNA-494 (miR-494) were mined based on Gene Expression Omnibus datasets and validated in both clinical samples and cell lines by quantitative real-time polymerase chain reaction and Western blot. The relationship between IGF2BP1 expression and clinicopathological factors of pancreatic cancer patients was analyzed. The effect and mechanism of IGF2BP1 on pancreatic cancer cell proliferation were investigated in vitro and in vivo. Analyses were performed to explore underlying mechanisms of IGF2BP1 upregulation in pancreatic cancer and assays were carried out to verify the post-transcriptional regulation of IGF2BP1 by miR-494.

RESULTS

We found that IGF2BP1 was upregulated and associated with a poor prognosis in pancreatic cancer patients. We showed that downregulation of IGF2BP1 inhibited pancreatic cancer cell growth in vitro and in vivo via the AKT signaling pathway. Mechanistically, we showed that the frequent upregulation of IGF2BP1 was attributed to the downregulation of miR-494 expression in pancreatic cancer. Furthermore, we discovered that reexpression of miR-494 could partially abrogate the oncogenic role of IGF2BP1.

CONCLUSION

Our results revealed that upregulated IGF2BP1 promotes the proliferation of pancreatic cancer cells via the AKT signaling pathway and confirmed that the activation of IGF2BP1 is partly due to the silencing of miR-494.

Loss of miR-873 contributes to gemcitabine resistance in triple-negative breast cancer via targeting ZEB1

Gemcitabine-based chemotherapy is commonly applied for the treatment of breast cancer in a clinical setting. However, acquired resistance to chemotherapy primarily results in treatment failure and eventually culminates in patient mortality. Aberrant expression of microRNAs (miRNAs) has been demonstrated to be implicated in the development of chemoresistance; however, the role of miR-873 in the chemoresistance of breast cancer and its underlying mechanism have not been completely elucidated. Herein, using cell viability assays, the present study demonstrated that overexpression of miR-873 sensitized triple-negative breast cancer (TNBC) cells (MDA-MB-231 and BT549) towards gemcitabine treatment, while inhibition of miR-873 promoted resistance of TNBC cells to gemcitabine exposure. The 3' untranslated region of zinc finger E-box binding homeobox 1 (ZEB1) was predicted as a candidate target of miR-873, and the regulatory association between ZEB1 and miR-873 was validated with a dual luciferase assay. Reverse transcription-quantitative polymerase chain reaction and western blot analysis confirmed that miR-873 mimics reduced ZEB1 at mRNA and protein levels in MDA-MB-231 and BT549 cells. As ZEB1 was previously reported to interact with Yes associated protein (YAP) to promote cancer progression. The present study observed that miR-873 overexpression decreased the expression of YAP target genes AXL receptor tyrosine kinase, connective tissue growth factor and cysteine rich angiogenic inducer 61 at mRNA and protein levels. Additionally, elevation of the ZEB1 level and reduction of the miR-873 level were detected in gemcitabine-resistant MDA-MB-231 (MDA-MB-231GEMr) cells, which were accompanied with stronger proliferative ability, compared with parental cells. Overexpression of miR-873 or ZEB1 knockdown reversed chemoresistance of MDA-MB-231GEMr cells by inducing a notable cell growth arrest upon gemcitabine exposure. In conclusion, the data obtained by the present study demonstrated that the decrease of miR-873 promoted the development of gemcitabine resistance in TNBC via elevation of ZEB1 expression, which indicated that miR-873 may be a promising predictor for gemcitabine sensitivity in patients with TNBC.

circTP63 functions as a ceRNA to promote lung squamous cell carcinoma progression by upregulating FOXM1

Circular RNAs (circRNAs) are identified as vital regulators in a variety of cancers. However, the role of circRNA in lung squamous cell carcinoma (LUSC) remains largely unknown. Herein, we explore the expression profiles of circRNA and mRNA in 5 paired samples of LUSC. By analyzing the co-expression network of differentially expressed circRNAs and dysregulated mRNAs, we identify that a cell cycle-related circRNA, circTP63, is upregulated in LUSC tissues and its upregulation is correlated with larger tumor size and higher TNM stage in LUSC patients. Elevated circTP63 promotes cell proliferation both in vitro and in vivo. Mechanistically, circTP63 shares miRNA response elements with FOXM1. circTP63 competitively binds to miR-873-3p and prevents miR-873-3p to decrease the level of FOXM1, which upregulates CENPA and CENPB, and finally facilitates cell cycle progression.

Circular RNAs are known to regulate cancer. Here, the authors show that the circular RNA circTP63 promotes lung squamous cell carcinoma by competing with endogenous RNA to upregulate FOXM1.

MicroRNA-873 inhibits the proliferation and invasion of endometrial cancer cells by directly targeting hepatoma-derived growth factor

An accumulation of evidence has demonstrated that abnormal microRNA (miRNA or miR) expression is associated with different types of cancer, including endometrial cancer (EC). The dysregulation of miRNAs may serve important roles in the development and progression of EC by regulating multiple aggressive biological behaviors, including cell proliferation, apoptosis, metastasis and angiogenesis. An in-depth understanding of the miRNAs associated with EC initiation and progression may be crucial for identifying successful therapeutic techniques. miR-873 has been demonstrated to be dysregulated in different types of cancer. However, the expression status and regulatory roles of miR-873 are yet to be elucidated in EC. In the present study, reverse transcription-quantitative PCR was carried out to detect miR-873 expression in EC tissues and cell lines. Cell Counting Kit-8 and in vitro invasion assays were utilized to determine the influence of miR-873 on the proliferation and invasion of EC cells. miR-873 expression was revealed to be downregulated in EC tissues and cell lines. Decreased miR-873 expression was significantly associated with International Federation of Gynecology and Obstetrics stage and lymph node metastasis of patients with EC. Functional assays revealed that resumed miR-873 expression suppressed the proliferation and invasion of EC cells. Additionally, hepatoma-derived growth factor (HDGF) was indicated to be a direct target gene of miR-873 in EC cells. HDGF was highly expressed in EC tissues and inversely correlated with miR-873 expression. HDGF silencing also imitated the tumor-suppressor activity of miR-873 overexpression in EC cells. A series of rescue experiments identified that recovered HDGF expression hindered the anti-proliferative and anti-invasive roles of miR-873 upregulation in EC cells. In conclusion, the present study indicated that miR-873 serves an important role as a tumor suppressor in EC development by directly targeting HDGF. The results may provide a novel insight into clinical treatments, which can be used to prevent EC aggression.

LncRNA THOR promotes tongue squamous cell carcinomas by stabilizing IGF2BP1 downstream targets

THOR, a highly conserved lncRNA, is potentially involved in various cancer development. However, its involvement in tongue squamous cell carcinoma (TSCC) remains unclear. The present study aims to explore the biological function and molecular mechanism of THOR in TSCC progression. The expressions of THOR and IGF2BP1 in TSCC tissues and adjacent non-cancerous tongue tissues (ANT) were examined through qRT-PCR. THOR levels were manipulated in TSCC cells to explore its function in cancer progression in vitro and in vivo, which were subsequently evaluated by CCK8, colony formation assay, flow cytometry, xenograft tumor assays. In situ hybridization, RIP and Western blot assay were performed to explore the underlying molecular mechanisms. We discovered that THOR and IGF2BP1 were dramatically upregulated in TSCC tissues. The expression of THOR is positively correlated with IGF2BP1 mRNA level. THOR mediated IGF2 expression via interacting with IGF2BP1, and affected the downstream MEK-ERK signaling pathway to regulate TSCC cells proliferation. THOR/IGF2BP1/IGF2-MEK-ERK axis regulated the proliferation of TSCC cells, implying that THOR would be a promising therapeutic target for TSCC patients.

MicroRNA‑873 inhibits the progression of thyroid cancer by directly targeting ZEB1

Recent evidence has revealed that certain microRNAs (miRNAs) are dysregulated in thyroid cancer (TC), which has been associated with the pathogenesis and development of TC. Therefore, improved understanding of the detailed roles of miRNAs that are aberrantly expressed in TC may aid the development of valuable therapeutic methods for the management of patients with this malignancy. In this study, miRNA‑873‑5p (miR‑873) expression in TC tissues and cell lines was detected by reverse‑transcription quantitative polymerase chain reaction (RT‑qPCR). MTT and cell invasion assays were performed to investigate the effects of miR‑873 overexpression on TC cell proliferation and invasion in vitro. Bioinformatics analysis, luciferase reporter assay, RT‑qPCR and western blot analysis were employed to evaluate whether zinc finger E‑box‑binding homeobox 1 (ZEB1) is a direct target of miR‑873 in TC cells. The present study reported that miR‑873 was weakly expressed in human TC tissues and cell lines. Functionally, miR‑873 overexpression suppressed TC cell proliferation and invasion in vitro. Mechanistically, ZEB1 was predicted to be a putative target of miR‑873. In addition, miR‑873 was proposed to directly bind to the 3'‑untranslated region of ZEB1 and decrease its expression in TC cells at the mRNA and protein levels. Furthermore, ZEB1 expression was significantly upregulated in TC tissues and negatively correlated with miR‑873 expression. Furthermore, ZEB1 restoration partially reversed the suppressive effects of miR‑873 overexpression on TC cell proliferation and invasion. These results demonstrated that miR‑873 may serve tumour‑suppressive roles in the progression of TC, and its suppressive effects could be mediated by the inhibition of ZEB1. Therefore, miR‑873 may be a valuable therapeutic target in the management of patients with TC.

MiR-873-5p suppresses cell proliferation and epithelial-mesenchymal transition via directly targeting Jumonji domain-containing protein 8 through the NF-κB pathway in colorectal cancer

Colorectal cancer (CRC) is one of the most common leading causes of cancer-related deaths in the world. Recent studies showed that microRNAs (miRNAs) play important roles in the development of diseases, such as CRC. However, the role of miR-873-5p in CRC remains unclear. In this study, we found that miR-873-5p expression was down-regulated in CRC tissues and cell lines, and the down-regulation of miR-873-5p expression was associated with poor survival in patients with CRC. MiR-873-5p could function as a tumour suppressor in CRC. It could inhibit the growth, proliferation, migration and invasion of CRC cells; influence the cell cycle and enhance apoptosis of CRC cells. Bioinformatics and luciferase reporter analyses demonstrated that Jumonji domain-containing protein 8 (JMJD8) was a target of miR-873-5p that could directly target the 3'UTR of JMJD8 and significantly inhibit its expression in CRC cells. This study also verified that JMJD8 functioned as an oncogene in CRC cells. The over-expression of JMJD8 could partly save the harmful effects induced by miR-873-5p in CRC cells, demonstrating that miR-873-5p suppressed carcinogenesis by targeting JMJD8 in CRC. We also verified that miR-873-5p over-expression could suppress CRC cell growth by inhibiting JMJD8 and its downstream NF-κB pathway in CRC. Hence, miR-873-5p inhibited tumour growth, and it may be a potential biomarker and a promising treatment for CRC.

LINC01420 RNA structure and influence on cell physiology

Background

It was shown that the major part of human genome is transcribed and produces a large number of long noncoding RNAs (lncRNAs). Today there are many evidences that lncRNAs play important role in the regulation of gene expression during different cellular processes. Moreover, lncRNAs are involved in the development of various human diseases. However, the function of the major part of annotated transcripts is currently unknown, whereas different lncRNAs annotations tend to have low overlap. Recent studies revealed that some lncRNAs have small open reading frames (smORFs), that produce the functional microproteins. However, the question whether the function of such genes is determined by microprotein or RNA itself or both remains open. Thus, the study of new lncRNA genes is important to understanding the functional role of such a heterogeneous class of genes.

Results

In the present study, we used reverse transcription PCR and rapid amplification of cDNA ends (RACE) analysis to determine the structure of the LINC01420 transcript. We revealed that LINC01420 has two isoforms that differ in length of the last exon and are localized predominantly in the cytoplasm. We showed that expression of the short isoform is much higher than the long. Besides, MTT and wound-healing assays revealed that LINC01420 inhibited cell migration in human melanoma cell line A375, but does not influence on cell viability.

Conclusion

During our work, D’Lima et al. found smORF in the first exon of the LINC01420 gene. This smORF produces functional microprotein named non-annotated P-body dissociating polypeptide (NoBody). However, our results provide new facts about LINC01420 transcript and its function.

The miR-873/NDFIP1 axis promotes hepatocellular carcinoma growth and metastasis through the AKT/mTOR-mediated Warburg effect

Hepatocellular carcinoma (HCC) progression depends on cellular metabolic reprogramming as both direct and indirect consequence of oncogenic lesions. However, the underlying mechanisms are still understood poorly. Here, we report that miR-873 promotes Warburg effect in HCC cells by increasing glucose uptake, extracellular acidification rate (ECAR), lactate production, and ATP generation, and decreasing oxygen consumption rate (OCR) in HCC cells. Mechanistically, we show that miR-873 activates the key glycolytic proteins AKT/mTOR via targeting NDFIP1 which triggers metabolic shift. We further demonstrate that enhanced glycolysis is essential for the role of miR-873 to drive HCC progression. By using immunohistochemistry analysis, we show a link between the aberrant expression of miR-873, NDFIP1, and phospho-AKT in clinical HCC samples. We also found that miR-873 was up-regulated by HIF1α, a critical glycolysis-related transcription factor. However, BAY 87-2243, a HIF1α specific inhibitor, blocks miR-873 mediated tumor growth and metastasis in nude mice. Collectively, our data uncover a previously unappreciated function of miR-873 in HCC cell metabolism and tumorigenesis, suggesting that targeting miR-873/NDFIP1 axis could be a potential therapeutic strategy for the treatment of HCC patients.

microRNA-4500 inhibits human glioma cell progression by targeting IGF2BP1

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) overexpression promotes glioma cell progression. The aim of the current study is to silence IGF2BP1 in glioma cells by the microRNA (miRNA) strategy. The bio-informatic analyses identified that microRNA-4500 (miR-4500) putatively targets 3'-UTR (3'-untranslated region) of IGF2BP1. In A172 cells and primary human glioma cells ectopic overexpression of the wild-type miR-4500 (but not the mutant form) downregulated IGF2BP1 and its target genes (Gli1, IGF2 and c-Myc). Functional studies show that ectopic miR-4500 overexpression inhibited glioma cell growth, survival, proliferation, migration and invasion. Conversely, in A172 cells miR-4500 inhibition, by a lentiviral construct, increased expression of IGF2BP1 and its targets, promoting cell survival, proliferation and migration. Furthermore, IGF2BP1 knockout by the CRISPR/Cas9 method inhibited A172 cell progression. Significantly, miR-4500 overexpression or miR-4500 inhibition was ineffective in IGF2BP1 knockout A172 cells. At last, we show that miR-4500 levels are downregulated in human glioma tissues, correlating with IGF2BP1 upregulation. Together, we conclude that miR-4500 inhibits human glioma cell progression by targeting IGF2BP1.

Extracellular vesicle-dependent effect of RNA-binding protein IGF2BP1 on melanoma metastasis

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is a multifunctional RNA-binding protein with an oncofetal pattern of expression shown to be implicated in the development of a variety of malignancies. In this study, we explored the role and mechanisms of IGF2BP1 in melanoma development and progression. In two different in vivo models, we showed that while genetic deletion or shRNA-mediated suppression of IGF2BP1 did not affect primary tumor formation, it drastically suppressed lung metastasis. Here we demonstrated that extracellular vesicles (EVs) secreted by melanoma cells mediate the effects of IGF2BP1 on metastasis: EVs from the IGF2BP1 knockdown melanoma cells failed to promote metastasis whereas EVs isolated from IGF2BP1-overexpressed melanoma cells further accelerated EV-induced metastasis. Moreover, the EVs from IGF2BP1 knockdown melanoma cells inhibited fibronectin deposition and accumulation of CD45⁺ cells in the lungs compared to control EVs, thus blocking the pre-metastatic niche formation potential of EVs. IGF2BP1 knockdown did not affect size, number, or protein/RNA concentration of secreted EVs or their uptake by recipient cells in vitro or in vivo. However, RNA-sequencing and proteomics analysis of the EVs revealed differential expression in a number of mRNA, proteins and miRNAs. This suggested that IGF2BP1 is intimately involved in the regulation of the cargo of EVs, thereby affecting the pro-metastatic function of melanoma-derived EVs. To the best of our knowledge, this is the first study that demonstrates the role of RNA-binding protein IGF2BP1 in EV-mediated promotion of melanoma metastasis and may provide novel avenues for the development of metastatic inhibitors.

MiR-873/PD-L1 axis regulates the stemness of breast cancer cells

Background

Breast cancer stem cells have self-renewal capability and are resistant to conventional chemotherapy. PD-L1 could promote the expression of stemness markers (OCT4 and Nanog) in breast cancer stem cells. However, the mechanisms by which PD-L1 regulates the stemness of breast cancer cells and PD-L1 is regulated in breast cancer cells are still unclear.

Methods

Lentivirus infection was used to construct stable cell lines. The correlation between PD-L1 and stemness markers expression was evaluated in clinical samples. Additionally, luciferase reporter assay combined with RNA-Fluorescence in situ hybridization (RNA-FISH) and RNA-binding protein immunoprecipitation (RIP) assays were used to verify the direct binding of miR-873 on PD-L1. Furthermore, flow cytometry, mammosphere formation combined with nude mouse tumor xenograft model were carried out to examine the effects of miR-873/PD-L1 axis on the stemness of breast cancer cells. Finally, MTT assay was performed to determine the effects of miR-873/PD-L1 axis on drug resistance.

Findings

PD-L1 expression was positively correlated with the expression of stemness markers, and overexpression of PD-L1 contributed to chemoresistance and stemness-like properties in breast cancer cells via activating PI3K/Akt and ERK1/2 pathways. Mechanistically, miR-873 inhibited PD-L1 expression through directly binding to its 3′-untranslated region (UTR), and miR-873 attenuated the stemness and chemoresistance of breast cancer cells which was dependent on PD-L1 and the downstream PI3K/Akt and ERK1/2 signaling. Notably, the promotion of PD-L1 on the stemness and chemoresistance was enhanced by recombinant PD-1 (rPD-1), this effect was attenuated by PD-1/PD-L1 inhibitor.

Interpretation

miR-873/PD-L1 regulatory axis might serve as a therapeutic target to enhance the chemo-sensitivity and eliminate the stemness of breast cancer cells.

Fund

This work was supported by the National Nature Science Foundation of China, No. 81702957, China Postdoctoral Science Foundation, No. 2017M620230, the Postdoctoral Research Funding Scheme of Jiangsu Province (2017), No. 1701197B, and the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions.

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A critical role of PD-L1 in stemness and chemoresistance is proposed.

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A negative miR-873/PD-L1 interaction was identified in breast cancer cells.

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The mechanisms of miR-873/PD-L1 in stemness and chemoresistance were studied.

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The results provide new insights for breast cancer progression and treatment.

The Modulatory Role of MicroRNA-873 in the Progression of KRAS-Driven Cancers

KRAS is one of the most frequently mutated proto-oncogenes in pancreatic ductal adenocarcinoma (PDAC) and aberrantly activated in triple-negative breast cancer (TNBC). A profound role of microRNAs (miRNAs) in the pathogenesis of human cancer is being uncovered, including in cancer therapy. Using in silico prediction algorithms, we identified miR-873 as a potential regulator of KRAS, and we investigated its role in PDAC and TNBC. We found that reduced miR-873 expression is associated with shorter patient survival in both cancers. miR-873 expression is significantly repressed in PDAC and TNBC cell lines and inversely correlated with KRAS levels. We demonstrate that miR-873 directly bound to the 3′ UTR of KRAS mRNA and suppressed its expression. Notably, restoring miR-873 expression induced apoptosis; recapitulated the effects of KRAS inhibition on cell proliferation, colony formation, and invasion; and suppressed the activity of ERK and PI3K/AKT, while overexpression of KRAS rescued the effects mediated by miR-873. Moreover, in vivo delivery of miR-873 nanoparticles inhibited KRAS expression and tumor growth in PDAC and TNBC tumor models. In conclusion, we provide the first evidence that miR-873 acts as a tumor suppressor by targeting KRAS and that miR-873-based gene therapy may be a therapeutic strategy in PDAC and TNBC.

MicroRNA‑409 may function as a tumor suppressor in endometrial carcinoma cells by targeting Smad2

MicroRNAs (miRNAs) are frequently dysregulated in human cancer and can act as either potent oncogenes or tumor suppressor genes. The aberrant expression of miRNA‑409 (miR‑409) has been found in certain types of cancer, however, its expression and potential biological role in endometrial cancer remain to be fully elucidated. In the present study, a total of 16 pairs of tissue samples from 16 patients with endometrial cancer were used in the present study, each of which consisted of human endometrial cancer tissue and matched adjacent normal tissue from the same patient. The expression of miR‑409 of the tissue were detected and its associations with Ishikawa and HEC‑1B human endometrial cancer cell lines were studied. The results of the present study demonstrated that miR‑409 was downregulated in human endometrial cancer, and it suppressed the growth of Ishikawa and HEC‑1B human endometrial cancer cell lines. Bioinformatics analysis indicated that small mothers against decapentaplegic 2 (Smad2) was a putative target of miR‑409. In a luciferase reporter system, it was confirmed that Smad2 was a direct target gene of miR‑409. It was also demonstrated that Smad2 was upregulated in human endometrial cancer tissues, and this was inversely correlated with the expression of miR‑409. These findings indicated that miR‑409 targeted the Smad2 transcript and suppressed endometrial cancer cell growth, suggesting that miR‑409 has a tumor suppressive role in the pathogenesis of human endometrial cancer.

MiR-873 inhibition enhances gefitinib resistance in non-small cell lung cancer cells by targeting glioma-associated oncogene homolog 1

BACKGROUND

The five-year survival rate of non-small cell lung cancer (NSCLC) patients is very low. MiR-873 is involved in the growth, metastasis, and differentiation of tumors. Herein, we determined the target gene and influence of miR-873 in NSCLC.

METHODS

MiRanda and Targetscan websites were used to predict the target gene of miR-873 in NSCLC. Luciferase activity was examined using a dual luciferase reporter gene assay kit. The viability, tube formation, and proliferation of cells were analyzed by cell counting kit-8, angiogenic analysis, and flow cytometry, respectively. The levels of miR-873 and GLI1 were evaluated using quantitative real-time PCR and Western blot assays.

RESULTS

Low levels of GLI1 and high levels of miR-873 were observed in an NSCLC cell line (PC9) highly sensitive to EGFR-tyrosine kinase inhibitors. There was a negative correlation between miR-873 and GLI1 expression in PC9 and PC9/GR cells. The inhibition of miR-873 enhanced GLI1 levels. MiR-873 expression was inhibited by gefitinib. Gefitinib markedly reduced the viability, tube formation, and cell number in PC9 cells. However, suppression of miR-873 enhanced the resistance and knockdown of GLI1 enhanced the sensitivity of PC9 cells to gefitinib.

CONCLUSIONS

GLI1 is a target gene of miR-873 in NSCLC. The inhibition of miR-873 increased gefitinib resistance of NSCLC cells via the upregulation of GLI1. These results indicate that miR-873-GLI1 signaling is involved in gefitinib resistance in NSCLC.

The E3 ligase for metastasis associated 1 protein, TRIM25, is targeted by microRNA-873 in hepatocellular carcinoma

Tumor metastasis accounts for 90% of all cancer-related deaths. Epithelial to mesenchymal transition (EMT) considered to be centrally important in acquired resistance to chemotherapy and in progression of tumors to secondary organs. One of the important mediators of metastatic progression in hepatocellular carcinoma (HCC) is the metastasis associated protein 1 (MTA-1). We have earlier shown that in the context of HCC and normal liver cell lines, MTA-1 protein is actively stabilized in HCC cell lines and actively degraded in normal liver cells. We have also shown that TRIM25 is the E3 ligase that interacts with and degrades MTA-1 protein. The identity of the factor regulating expression of TRIM25 in normal liver cells and HCC is unknown. In the current work we elucidate that microRNA (miR)- 873 targets TRIM25 in HCC cells. Both metagenomic analysis and quantification of miR-873 and TRIM25 in 25 HCC patients revealed an inverse correlation between the two in HCC patients with high miR-873 and low TRIM25 expression, respectively. The expression pattern was mimicked in the normal liver cells THLE-2 and the HCC cell line, HuH6. In vitro luciferase reporter assays confirmed TRIM25 as the target of miR-873. Transient transfection of HuH6 cells with an anti-miR-873 antagomir significantly decreased both transwell motility in these cells. Furthermore, in in vivo xenograft assays treatment with anti-miR-873 antagomir significantly decreased hepatic nodules formation. Cumulatively, our data indicate that suppression of TRIM25 expression by high levels of miR-873 dictates MTA1 protein upregulation in HCC.

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) in cancer

The insulin-like growth factor-2 mRNA-binding protein 1 (IGF2BP1) plays essential roles in embryogenesis and carcinogenesis. IGF2BP1 serves as a post-transcriptional fine-tuner regulating the expression of some essential mRNA targets required for the control of tumor cell proliferation and growth, invasion, and chemo-resistance, associating with a poor overall survival and metastasis in various types of human cancers. Therefore, IGF2BP1 has been traditionally regarded as an oncogene and potential therapeutic target for cancers. Nevertheless, a few studies have also demonstrated its tumor-suppressive role. However, the details about the contradictory functions of IGF2BP1 are unclear. The growing numbers of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have been identified as its direct regulators, during tumor cell proliferation, growth, and invasion in multiple cancers. Thus, the mechanisms of post-transcriptional modulation of gene expression mediated by IGF2BP1, miRNAs, and lncRNAs in determining the fate of the development of tissues and organs, as well as tumorigenesis, need to be elucidated. In this review, we summarized the tissue distribution, expression, and roles of IGF2BP1 in embryogenesis and tumorigenesis, and focused on modulation of the interconnectivity between IGF2BP1 and its targeted mRNAs or non-coding RNAs (ncRNAs). The potential use of inhibitors of IGF2BP1 and its related pathways in cancer therapy was also discussed.

MicroRNA-873 acts as a tumor suppressor in esophageal cancer by inhibiting differentiated embryonic chondrocyte expressed gene 2

Esophageal cancer is one of the most common digestive malignant diseases worldwide and emerging evidences revealed that microRNAs (miRNAs) were implicated in the development and progression of esophageal cancer. However, the expression level and biological function of microRNA-873(miR-873) in esophageal cancer are still largely elusive. In this study, we investigated the expression and biological roles of miR-873 in human esophageal cancer. Our results revealed that miR-873 was significantly underexpressed in esophageal cancer tissues and cell lines when compared with the para-tumor tissue and primary human esophageal epithelial cells. Furthermore, overexpression of miR-873 could remarkably inhibit esophageal cancer cell growth, migration and invasion. Moreover, we validated differentiated embryonic chondrocyte expressed gene 2 (DEC2) as a direct target of miR-873 which could reverse the repressive effects of miR-873 on esophageal cancer cell. In summary, our investigation demonstrated that miR-873 was underexpressed in esophageal cancer and might act as a tumor suppressor gene by directly targeting DEC2.

miR‑873 inhibits colorectal cancer cell proliferation by targeting TRAF5 and TAB1

MicroRNA-873 (miR-873) has been reported to be dysregulated in a variety of malignancies, however, the biological function and underlying molecular mechanism of miR-873 in colorectal cancer (CRC) remain unclear. In the present study we found that the expression levels of miR-873 were markedly decreased in CRC cell lines and tissues from patients. Statistical analysis revealed that miR-873 expression was inversely correlated with the disease stage of CRC. Kaplan-Meier survival analysis revealed that patients with CRC with lower miR-873 expression had shorter overall survival rates. Additionally, downregulation of miR-873 enhanced the proliferation of CRC cells, while upregulation of miR-873 reduced this proliferation. Furthermore, we found that tumor necrosis factor (TNF) receptor-associated factor 5 (TRAF5) and TGF-β activated kinase 1 (MAP3K7) binding protein 1 (TAB1) were direct targets of miR-873 in CRC cells. A luciferase assay revealed that ectopic expression of miR-873 significantly reduced nuclear factor κB (NF-κB) luciferase activity, while ectopic expression of miR-873 inhibitor enhanced luciferase activity, suggesting that downregulation of miR-873 can activate NF-κB signaling. Therefore, our findings established a tumor-suppressive role for miR-873 in the inhibition of CRC progression, which may be employed as a novel prognostic marker and as an effective therapeutic target for CRC.

A support vector machine and a random forest classifier indicates a 15-miRNA set related to osteosarcoma recurrence

BACKGROUND

Osteosarcoma, which originates in the mesenchymal tissue, is the prevalent primary solid malignancy of the bone. It is of great importance to explore the mechanisms of metastasis and recurrence, which are two primary reasons accounting for the high death rate in osteosarcoma.

DATA AND METHODS

Three miRNA expression profiles related to osteosarcoma were downloaded from GEO DataSets. Differentially expressed miRNAs (DEmiRs) were screened using MetaDE.ES of the MetaDE package. A support vector machine (SVM) classifier was constructed using optimal miRNAs, and its prediction efficiency for recurrence was detected in independent datasets. Finally, a co-expression network was constructed based on the DEmiRs and their target genes.

RESULTS

In total, 78 significantly DEmiRs were screened. The SVM classifier constructed by 15 miRNAs could accurately classify 58 samples in 65 samples (89.2%) in the GSE39040 database, which was validated in another two databases, GSE39052 (84.62%, 22/26) and GSE79181 (91.3%, 21/23). Cox regression showed that four miRNAs, including hsa-miR-10b, hsa-miR-1227, hsa-miR-146b-3p, and hsa-miR-873, significantly correlated with tumor recurrence time. There were 137, 147, 145, and 77 target genes of the above four miRNAs, respectively, which were assigned to 17 gene ontology functionally annotated terms and 14 Kyoto Encyclopedia of Genes and Genomes pathways. Among them, the "Osteoclast differentiation" pathway contained a total of seven target genes and was analyzed further.

CONCLUSION

The 15-miRNAs-based SVM classifier provides a potential useful tool to predict the recurrence of osteosarcoma. Our results suggest the possible mechanisms of osteosarcoma metastasis and recurrence and provide fresh DEmiRs as potential biomarkers or therapeutic targets for osteosarcoma.

MicroRNA-873 inhibits colorectal cancer metastasis by targeting ELK1 and STRN4

MicroRNAs (miRNAs) are a group of small non-coding RNAs that directly bind to the 3ʹ-untranslated-region (3ʹUTR) of mRNA, thereby blocking gene expression post-transcriptionally. Accumulating evidence prove that microRNA-873 (miR-873) functions as a promoter or suppressor in various cancers, while whether it affects the progression of colorectal cancer (CRC) is yet unknown. Here we found that miR-873 was downregulated in human CRC clinical samples, mouse CRC specimens and cell lines with high metastatic potential. We also demonstrated that low miR-873 expression was closely associated with poor prognosis of CRC. Overexpressing miR-873 suppressed proliferation and metastasis of CRC cells both in vitro and in vivo, while inhibiting miR-873 expression promoted the proliferation, migration and invasion in vitro. Moreover, miR-873 exerted its function by perturbing the ERK-CyclinD1 pathway and the epithelial-mesenchymal transition (EMT) process. Furthermore, we revealed that miR-873 acted as a tumor-suppressive microRNA by directly binding to the 3ʹUTRs of ELK1 and STRN4 and suppressed their expression. Our study uncovered an inhibitory role of miR-873 in CRC progression and might provide a promising marker for CRC diagnosis and prognosis.

Prediction of miRNA-disease Associations using an Evolutionary Tuned Latent Semantic Analysis

MicroRNAs, small non-coding elements implied in gene regulation, are very interesting biomarkers for various diseases such as cancers. They represent potential prodigious biotechnologies for early diagnosis and gene therapies. However, experimental verification of microRNA-disease associations are time-consuming and costly, so that computational modeling is a proper solution. Previously, we designed MiRAI, a predictive method based on distributional semantics, to identify new associations between microRNA molecules and human diseases. Our preliminary results showed very good prediction scores compared to other available methods. However, MiRAI performances depend on numerous parameters that cannot be tuned manually. In this study, a parallel evolutionary algorithm is proposed for finding an optimal configuration of our predictive method. The automatically parametrized version of MiRAI achieved excellent performance. It highlighted new miRNA-disease associations, especially the potential implication of mir-188 and mir-795 in various diseases. In addition, our method allowed to detect several putative false associations contained in the reference database.

IGF2BP1 overexpression causes fetal-like hemoglobin expression patterns in cultured human adult erythroblasts

Here we investigated in primary human erythroid tissues a downstream element of the heterochronic let-7 miRNA pathway, the insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), for its potential to affect the hemoglobin profiles in human erythroblasts. Comparison of adult bone marrow to fetal liver lysates demonstrated developmental silencing in IGF2BP1. Erythroid-specific overexpression of IGF2BP1 caused a nearly complete and pancellular reversal of the adult pattern of hemoglobin expression toward a more fetal-like phenotype. The reprogramming of hemoglobin expression was achieved at the transcriptional level by increased gamma-globin combined with decreased beta-globin transcripts resulting in gamma-globin rising to 90% of total beta-like mRNA. Delta-globin mRNA was reduced to barely detectable levels. Alpha-globin levels were not significantly changed. Fetal hemoglobin achieved levels of 68.6 ± 3.9% in the IGF2BP1 overexpression samples compared with 5.0 ± 1.8% in donor matched transduction controls. In part, these changes were mediated by reduced protein expression of the transcription factor BCL11A. mRNA stability and polysome studies suggest IGF2BP1 mediates posttranscriptional loss of BCL11A. These results suggest a mechanism for chronoregulation of fetal and adult hemoglobin expression in humans.

miR-873 suppresses H9C2 cardiomyocyte proliferation by targeting GLI1

MicroRNAs (miRNAs) are a class of endogenous, non-coding small RNAs that regulate the expression of target genes. Previous studies have suggested that miRNAs are key regulators in cardiovascular systems. This study investigated the role of miR-873 in H9C2 cardiomyocytes by targeting glioma-associated oncogene 1 (GLI1). miR-873 was significantly up-regulated in serum samples from congenital heart disease (CHD) patients compared with those from normal individuals. Furthermore, miR-873 over-expression suppressed H9C2 proliferation and induced cell cycle arrest. Bioinformatic algorithms revealed a predicted target site for miR-873 in the 3'-untranslated region (3'UTR) of GLI1, which was verified using a dual-luciferase reporter assay. qPCR and western blot analysis also showed that miR-873 negatively regulated GLI1 mRNA and protein expression in H9C2 cells. Conversely, GLI1 over-expression partially reversed the growth-inhibitory effect of miR-873. To summarize, our data suggest that miR-873 is a novel miRNA that regulates H9C2 cell proliferation via targeting GLI1, and miR-873 may serve as a new potential biomarker diagnosis in CHD in the future.

A Comprehensive Review of Genomics and Noncoding RNA in Gliomas

Glioblastoma (GBM) is the most malignant primary adult brain tumor. In spite of our greater understanding of the biology of GBMs, clinical outcome of GBM patients remains poor, as their median survival with best available treatment is 12 to 18 months. Recent efforts of The Cancer Genome Atlas (TCGA) have subgrouped patients into 4 molecular/transcriptional subgroups: proneural, neural, classical, and mesenchymal. Continuing efforts are underway to provide a comprehensive map of the heterogeneous makeup of GBM to include noncoding transcripts, genetic mutations, and their associations to clinical outcome. In this review, we introduce key molecular events (genetic and epigenetic) that have been deemed most relevant as per studies such as TCGA, with a specific focus on noncoding RNAs such as microRNAs (miRNA) and long noncoding RNAs (lncRNA). One of our main objectives is to illustrate how miRNAs and lncRNAs play a pivotal role in brain tumor biology to define tumor heterogeneity at molecular and cellular levels. Ultimately, we elaborate how radiogenomics-based predictive models can describe miRNA/lncRNA-driven networks to better define heterogeneity of GBM with clinical relevance.

MicroRNAs in glioblastoma multiforme pathogenesis and therapeutics

Glioblastoma multiforme (GBM) is the most common and lethal cancer of the adult brain, remaining incurable with a median survival time of only 15 months. In an effort to identify new targets for GBM diagnostics and therapeutics, recent studies have focused on molecular phenotyping of GBM subtypes. This has resulted in mounting interest in microRNAs (miRNAs) due to their regulatory capacities in both normal development and in pathological conditions such as cancer. miRNAs have a wide range of targets, allowing them to modulate many pathways critical to cancer progression, including proliferation, cell death, metastasis, angiogenesis, and drug resistance. This review explores our current understanding of miRNAs that are differentially modulated and pathologically involved in GBM as well as the current state of miRNA-based therapeutics. As the role of miRNAs in GBM becomes more well understood and novel delivery methods are developed and optimized, miRNA-based therapies could provide a critical step forward in cancer treatment.

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

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

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

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

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

miR-503 inhibits cell proliferation and invasion in glioma by targeting L1CAM

Deregulated microRNAs and their roles in tumorigenesis have attracted much attention in recent years. Although miR-503 has been reported to be aberrant expression in several cancers, its role in glioma remains unknown. In this study, we focused on the expression and mechanisms of miR-503 in glioma development. We found that miR-503 was downregulated in glioma cell lines and tumor tissues, and the restoration of miR-503 reduced cell proliferation invasion. Furthermore, bioinformatics analysis indicated that L1CAM was a putative target of miR-503. In a Luciferase reporter system, we confirmed that L1CAM was a direct target gene of miR-503. These findings indicate that miR-503 suppresses glioma cell growth by negatively regulating the expression of L1CAM. Collectively, our data identify the important roles of miR-503 in glioma pathogenesis, indicating its potential application in cancer therapy.

MicroRNA as potential biomarkers in Glioblastoma

Glioblastoma is the most aggressive and lethal tumour of the central nervous system and as such the identification of reliable prognostic and predictive biomarkers for patient survival and tumour recurrence is paramount. MicroRNA detection has rapidly emerged as potential biomarkers, in patients with glioblastoma. Over the last decade, analysis of miRNA in laboratory based studies have yielded several candidates as potential biomarkers however, the accepted use of these candidates in the clinic is yet to be validated. Here we will examine the use of miRNA signatures to improve glioblastoma stratification into subgroups and summarise recent advances made in miRNA examination as potential biomarkers for glioblastoma progression and recurrence.