Downregulation of miR‑429 and inhibition of cell migration and invasion in nasopharyngeal carcinoma

METTL13 promotes nasopharyngeal carcinoma progression through regulating the ZEB1/TPT1 axis

BACKGROUND

Globally, nasopharyngeal carcinoma (NPC) is a prevalent and deadly malignancy. Despite the role of methyltransferase like 13 (METTL13) having been highlighted in a majority of human cancers, its function and mechanism in NPC is indistinct.

METHODS

The expression level of METTL13 in NPC cell lines and normal cells was detected using a quantitative real-time polymerase chain reaction. Gain- and loss-of function experiments were conducted. Cell counting kit-8, 5-ethynyl-2'-deoxyuridine, wound-healing, Transwell and tube formation assays, respectively, appraised the proliferative, migratory, invasive and angiogenic cellular responses. Corresponding protein expression was measured by western blotting. A chromatin immunoprecipitation assay was applied to verify the association between ZEB1 and the TPT1 promoter. Eventually, to substantiate the critical role of METTL13 in NPC, the establishment of an in vivo tumorigenesis model was accomplished.

RESULTS

METTL13 possessed fortified expression in NPC cells. METTL13 silencing markedly suppressed NPC cellular phenotypes in vitro, including proliferative, migratory, invasive and angiogenic events, as well as hindered tumorigenesis in vivo. Additionally, METTL13 positively regulated ZEB1, whereas ZEB1 could bind to TPT1 promoter and transcriptionally regulate TPT1. TPT1 was also found to be upregulated in NPC cells. TPT1 silencing suppressed NPC cellular phenotypes in vitro. TPT1 overexpression partly weakened the anti-tumor effect of METTL13 in NPC.

CONCLUSIONS

In summary, METTL13 up-regulated ZEB1, which facilitated the transcriptional activation of TPT1, ultimately promoting NPC growth and metastasis, providing a potential therapeutic strategy for NPC treatment.

lncRNA MSC-AS1/miRNA-429 Axis Mediates Growth and Metastasis of Nasopharyngeal Carcinoma via JAK1/STAT3 Signaling Pathway

Objective. We attempted to clarify the effect of lncRNA MSC-AS1 on carcinogenic and development of nasopharyngeal carcinoma (NPC) and the related mechanisms. Methods. The levels of MSC-AS1 and miR-429 were estimated in NPC tissues and cells using qRT-PCR. Correlation analysis, dual-luciferase report, and RNA pull down assay assessed the action association of MSC-AS1 and miR-429. MTT, colony formation, cell wound scratch, and transwell assays were used to assess the proliferation, invasion, and migration of C666-1 cells. Metastasis-related protein expressions and activation of the JAK1/STAT3 pathway were confirmed by western blot and immunohistochemistry. Results. The expression of MSC-AS1 presented significant upregulation, and miR-429 expression was markedly downregulated in NPC tissues and cells. The level of MSC-AS1 had negative relation to the miR-429 level. Knockdown of MSC-AS1 suppressed the proliferation, invasion, and migration of C666-1 cells. On the contrary, overexpressing of MSC-AS1 exerts the opposite effects on C666-1 cell growth and migration. miR-429 was determined as functional downstream of MSC-AS1. The suppressive function of MSC-AS1 knockdown was predominately abolished by the miR-429 inhibitor. miR-429 was an antitumor gene inhibiting NPC growth and metastasis through JAK1/STAT3 pathway. In C666-1 cells, the elevated cell growth and migration induced by the miR-429 inhibitor were significantly reversed by si-JAK1 transfection. Conclusions. High expression of MSC-AS1 exerted a carcinogenic effect on NPC cell growth and metastasis by inhibiting miR-429 and activating the JAK1/STAT3 pathway.

Advances in research on microRNAs related to the invasion and metastasis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC), which is associated with latent Epstein-Barr virus infection in most cases, is a unique epithelial malignancy arising from the nasopharyngeal mucosal lining. Accumulating evidence provides insights into the genetic and molecular aberrations that likely drive nasopharyngeal tumor development and progression. We review recent analyses of microRNAs (miRNAs), including Epstein-Barr virus-encoded miRNAs (EBV-encoded miRNAs) and dysregulated cellular miRNAs, that may be related to the metastasis of nasopharyngeal carcinoma. The studies summarized herein have greatly expanded our knowledge of the molecular biology of NPC involving miRNAs, and they may provide new biological targets for clinical diagnosis and reveal the potential of microRNA therapeutics. However, much information remains to be uncovered.

The microRNA-429/DUSP4 axis regulates the sensitivity of colorectal cancer cells to nintedanib

Colorectal cancer (CRC) is recognized as one of the most common malignancies, which ranks third among all cancer-related deaths worldwide. Nintedanib is an orally available tyrosine kinase inhibitor that can treat CRC; however, drug resistance to nintedanib leads to unsatisfactory treatments for patients with CRC. The aim of the present study was to explore whether overexpression of miR-429 elevated the sensitivity of CRC cells to nintedanib by downregulating dual specificity protein phosphatase 4 (DUSP4). The nintedanib-resistant CRC cell model was established via the treatment of cells with nintedanib in a dose-dependent manner. Reverse transcription-quantitative PCR was used to detect the expression levels of miR-429 and DUSP4, and to confirm the transfection efficiency of miR-429 mimic and DUSP4 overexpression plasmid. Cell Counting Kit-8 assay was utilized to measure the inhibition rate of cells. Western blotting was conducted to observe the expression levels of DUSP4 protein, apoptosis-related proteins and proteins related to the JNK signaling pathway. Dual-luciferase reporter assay was performed to evaluate luciferase activity and TUNEL assay was conducted to detect the apoptosis of cells. The results revealed that miR-429 mimic elevated the sensitivity of CRC cells to nintedanib. Moreover, by ENCORI prediction, DUSP4 was identified as a target gene of miR-429, and overexpression of DUSP4 reversed the inducing effect of miR-429 overexpression on the sensitivity of CRC cells to nintedanib. In conclusion, overexpression of miR-429 may elevate the sensitivity of CRC cells to nintedanib through inhibition of the JNK signaling pathway by targeting DUSP4. These findings may aid in the prevention of drug resistance of CRC cells to nintedanib.

MicroRNA-429 inhibits bone metastasis in breast cancer by regulating CrkL and MMP-9

Bone metastasis is common in late-stage breast cancer patients and leads to skeletal-related events that affect the quality of life and decrease survival. Numerous miRNAs have been confirmed to be involved in metastatic breast cancer, such as the miR200 family. Our previous study identified microRNA-429 (miR-429) as a regulatory molecule in breast cancer bone metastasis. However, the effects of miR-429 and its regulatory axis in the metastatic breast cancer bone microenvironment have not been thoroughly investigated. We observed a positive correlation between miR-429 expression in clinical tissues and the bone metastasis-free interval and a negative correlation between miR-429 expression and the degree of bone metastasis. We cultured bone metastatic MDA-MB-231 cells and used conditioned medium (CM) to detect the effect of miR-429 on osteoblast and osteoclast cells in vitro. We constructed an orthotopic bone destruction model and a left ventricle implantation model to examine the effect of miR-429 on the metastatic bone environment in vivo. The transfection experiments showed that the expression levels of V-crk sarcoma virus CT10 oncogene homolog-like (CrkL) and MMP-9 were negatively regulated by miR-429. The in vitro coculture experiments showed that miR-429 promoted osteoblast differentiation and that CrkL promoted osteoclast differentiation. The two animal models showed that miR-429 diminished local bone destruction and distant bone metastasis but CrkL enhanced these effects. Furthermore, CrkL and MMP-9 expression decreased simultaneously in response to increased miR-429 expression. These findings further reveal the possible mechanism and effect of the miR-429/CrkL/MMP-9 regulatory axis in the bone microenvironment in breast cancer bone metastasis.

The effects of miR-429 on cell migration and invasion by targeting Slug in esophageal squamous cell carcinoma

Increasing evidence indicates that microRNAs may play important roles in tumor development and may take part in different processes in different cancers. miR-429 is known as a cancer suppressor or oncogene that is dysregulated in different malignancies, including esophageal squamous cell carcinoma (ESCC). However, the effect of miR-429 in ESCC has not been fully explored. The purpose of this study was to investigate the functions of miR-429 in ESCC. qRT-PCR assays were performed to detect miR-429 expression in ESCC tissues and cell lines. To assess the effects of miR-429 on ESCC cells, wound healing and transwell assays were used. Luciferase reporter and western blot assays were employed to determine whether Slug is a major target of miR-429.Our results showed that the expression levels of miR-429 in ESCC tissues and cells were lower than in normal esophageal epithelial tissues and cells. Furthermore, overexpression of endogenous miR-429 inhibited the migration and invasion of ESCC cell lines. In addition, Luciferase reporter and western blot assays provided evidence that miR-429 can bind to the 3' untranslated regions of Slug to regulate its expression and that of downstream epithelial-to-mesenchymal transition (EMT) markers. We found that Slug serves as a major target of miR-429. miR-429 plays a vital role in ESCC progression and represents a new therapeutic target for ESCC.

miR-429 suppresses cell proliferation, migration and invasion in nasopharyngeal carcinoma by downregulation of TLN1

Background

miR-429 and TLN1 have been shown to affect the biological behaviours of many carcinomas. However, their effects in nasopharyngeal carcinoma (NPC) are not yet clear. Here, we investigated their regulatory relationships and effects on NPC cells.

Methods

TargetScan was used to predict the regulatory relationships of miR-429 and TLN1 in NPC cells. Then, Western blotting and quantitative real-time PCR (qPCR) were performed to examine TLN1 levels, and qPCR was used to determine miR-429 levels in NPC cell lines with different metastatic characteristics (5-8F, CNE-2, CNE-1, 6-10B and NP69), to investigate whether TLN1 and miR-429 are correlated with the metastatic characteristics of these cells. Next, we upregulated or downregulated miR-429 in 5-8F and 6-10B cells, which have different tumourigenicity and transferability, and examined TLN1 expression by western blotting and qPCR after transfection. QPCR was also performed to confirm successful transfection of miR-429 mimic into 5-8F and 6-10B cells. Dual luciferase reporter gene assay was performed to investigate whether miR-429 regulates TLN1 by binding to its 3′UTR. After transfection, Cell Counting Kit-8 (CCK8) and IncuCyte were used to examine the proliferation of these cells, and wound-healing assay, Transwell migration assay, and invasion assays were performed to investigate the changes in migration and invasion after transfection.

Results

Western blotting and qPCR analyses showed that the protein level of TLN1 was negatively correlated with miR-429 in NPC cell lines (P < 0.05), while the mRNA level showed no relation with miR429 expression (P > 0.05). In addition, cells with high transferability showed high TLN1 expression at the protein level, while miR429 expression showed the opposite trend (P < 0.05), but there were no differences at the mRNA level between the different cell lines. Overexpression of miR429 in 5-8F and 6-10B cells was accompanied by downregulation of TLN1 at the protein level (P < 0.05), while there were no significant differences at the mRNA level (P > 0.05). In addition, transferability, proliferation, and invasion were downregulated by miR429 overexpression (P < 0.05). However, dual-luciferase reporter gene assay indicated that TLN1 was not a direct target of miR-429.

Conclusion

This study showed that miR-429 functions as a tumour suppressor in NPC by downregulation of TLN1, although the relationship is not direct.

MiR-429 improved the hypoxia tolerance of human amniotic cells by targeting HIF-1α

MicroRNA-429(miR-429) plays an important role in mesenchymal stem cells. Hypoxia-inducible factor 1α (HIF-1α) is a nuclear transcription factor that regulates the proliferation, apoptosis and tolerance to hypoxia of mesenchymal stem cells. HIF-1α is also a target gene of miR-429. We investigated whether miR-429 plays a role in hypoxia tolerance with HIF-1α in human amniotic mesenchymal stem cells (hAMSCs). The expression of miR-429 was increased by hypoxia in hAMSCs. miR-429 expression resulted in decreased HIF-1α protein level, but little effect on HIF-1α mRNA. While overexpression of HIF-1α increased the survival rate and exhibited anti-apoptosis effects in hAMSCs under hypoxia, co-expression of miR-429 reduced survival and increased apoptosis. However, miR-429 silencing with HIF-1α overexpression stimulated cell survival and reduced apoptosis. Co-expression of HIF-1α and miR-429 reduced VEGF and Bcl-2 proteins and increased Bax and C-Caspase-3 levels in hAMSCs under hypoxia compared with cells expressing only HIF-1α; cells with HIF-1α overexpression and miR-429 silencing showed the opposite effects. These results indicate that HIF-1α and angomiR-429 reciprocally antagonized each other, while HIF-1α and antagomiR-429 interacted with each other to regulate survival and apoptosis in hAMSCs under hypoxia. miR-429 increased VEGF and Bcl-2 protein levels and decreased Bax and cleaved Caspase-3 protein levels by promoting the synthesis of HIF-1α. These results indicate that miR-429 negatively regulates the survival and anti-apoptosis ability of hAMSCs by mediating HIF-1α expression and improves the ability of hAMSCs to tolerate hypoxia.

MicroRNA-342 inhibits cell proliferation and invasion in nasopharyngeal carcinoma by directly targeting ZEB1

Nasopharyngeal carcinoma (NPC) is prevalent in Africa and East Asia, particularly in the southern areas of China. Previous data has demonstrated that microRNAs (miRNAs/miRs) may be involved in the formation and progression of NPC. The deregulation of miR-342 has been identified in multiple types of cancer. However, to the best of our knowledge, there are no data concerning miR-342 in NPC. The present study aimed to measure miR-342 expression in NPC, and to investigate its roles in NPC initiation and progression, in addition to the underlying molecular mechanisms. miR-342 was significantly downregulated in NPC tissues and cell lines. Low miR-342 expression was associated with distant metastasis and tumor node metastasis stage in patients with NPC. The restoration of the expression of miR-342 suppressed cell proliferation and invasion of NPC in vitro. In addition, ZEB1 was identified as a direct target gene of miR-342 in NPC. Downregulation of ZEB1 mimicked the tumor-suppressive roles of miR-342 in NPC. Taken together, the present study identified that miR-342 directly targeted ZEB1 to inhibit NPC cell growth and invasion, which may provide a novel therapeutic target for the treatments of patients with this malignancy.

MiR-429 Regulated by Endothelial Monocyte Activating Polypeptide-II (EMAP-II) Influences Blood-Tumor Barrier Permeability by Inhibiting the Expressions of ZO-1, Occludin and Claudin-5

The blood-tumor barrier (BTB) hinders delivery of chemotherapeutic drugs to tumors in the brain; previous studies have shown that the BTB can be selectively opened by endothelial monocyte activating polypeptide-II (EMAP-II), but the specific mechanism involved remains elusive. In this study, we found that microRNA-429 (miR-429) expression in glioma vascular endothelial cells (GECs) was far lower than in human brain microvascular endothelial cells (ECs). miR-429 had lower expression in GECs and glioma tissues compared to ECs or normal tissues of the brain. Furthermore, miR-429 had lower expression in high grade glioma (HGG) than in low grade glioma (LGG). In in vitro BTB models, we also found that EMAP-II significantly increased BTB permeability, decreased expression of ZO-1, occludin and claudin-5 in GECs, in a time- and dose-dependent manner. EMAP-II greatly increased miR-429 expression in GECs of the BTB models in vitro. Overexpression of miR-429 in GECs significantly decreased the transepithelial electric resistance (TEER) values in BTB models, and led to enhanced horseradish peroxidase (HRP) flux. Overexpression of miR-429 in GECs significantly decreased the expression of tight junction (TJ)-associated proteins (ZO-1, occludin and claudin-5), and decreased the distribution continuity. Silencing of miR-429 in GECs increased the expression of TJ-associated proteins and the distribution continuity. The dual-luciferase reporter assay revealed that ZO-1 and occludin were target genes of miR-429, and we demonstrated that miR-429 overexpression markedly down-regulated protein expression of p70S6K, as well as its phosphorylation levels. The dual-luciferase reporter assay also showed that p70S6K was a target gene of miR-429; miR-429 overexpression down-regulated expression and phosphorylation levels of p70S6K, and also decreased phosphorylation levels of S6 and increased BTB permeability. Conversely, silencing of miR-429 increased the expression and phosphorylation levels of p70S6K, and increased phosphorylation levels of S6, while decreasing BTB permeability. In conclusion, the results indicated that EMAP-II caused an increase in miR-429 expression that directly targeted TJ-associated proteins, which were negatively regulated; on the other hand, miR-429 down-regulated the expression of TJ-associated proteins by targeting p70S6K, also negatively regulated. As a result, the BTB permeability increased.

miR-429 Inhibits Differentiation and Promotes Proliferation in Porcine Preadipocytes

MicroRNAs (miRNAs) are crucial regulatory molecules for adipogenesis. They contribute to the controlling of proliferation and differentiation of preadipocytes. Previous studies revealed an important role of miR-429 in cell invasion, migration, and apoptosis. Our previous work has shown that the expression of miR-429 in subcutaneous fat can be observed in newly born (3-day-old) Rongchang piglets rather than their adult counterparts (180-day-old). This expression pattern suggests that miR-429 might be functionally related to postnatal adipogenesis. However, we currently lack a mechanistic understanding of miR-429 within the context of preadipocyte differentiation. In this study, we investigated the function of miR-429 in porcine subcutaneous and intramuscular preadipocyte proliferation and differentiation. In our porcine preadipocyte differentiation model, miR-429 expression decreased remarkably upon adipogenic induction. Overexpression of miR-429 notably down-regulated the expression of adipogenic marker genes: PPARγ, aP2, FAS and impaired the triglyceride accumulation, while the expression of lipolytic gene ATGL was not affected. In addition, we observed that miR-429 significantly promoted the proliferation of porcine preadipocytes. We also found that miR-429 could directly bind to the 3′-UTRs of KLF9 and p27, which have been well documented to promote preadipocyte differentiation and repress cell cycle progression. Taken together, our data support a novel role of miR-429 in regulating porcine preadipocyte differentiation and proliferation, and KLF9 and p27 are potent targets of miR-429 during these processes.

MiR-429 is linked to metastasis and poor prognosis in renal cell carcinoma by affecting epithelial-mesenchymal transition

MicroRNAs (miRNAs) have been proven to be important oncogenes and tumor suppressors in wide range of cancers, including renal cell carcinoma (RCC). In our study, we evaluated miRNA-429 as potential diagnostic/prognostic biomarker in 172 clear cell RCC patients and as a potential regulator of epithelial-mesenchymal transition (EMT) in vitro. We demonstrated that miR-429 is down-regulated in tumor tissue samples (P < 0.0001) and is significantly associated with cancer metastasis (P < 0.0001), shorter disease-free (P = 0.0105), and overall survival (P = 0.0020). In addition, ectopic expression of miR-429 in 786-0 RCC cells followed by TGF-β treatment led to increase in the levels of E-cadherin expression (P < 0.0001) and suppression of cellular migration (P < 0.0001) in comparison to TGF-β-treated controls. Taken together, our findings suggest that miR-429 may serve as promising diagnostic and prognostic biomarker in RCC patients. We further suggest that miR-429 has a capacity to inhibit loss of E-cadherin in RCC cells undergoing EMT and consequently attenuate their motility.

Increased Serum Level of MicroRNA-663 Is Correlated with Poor Prognosis of Patients with Nasopharyngeal Carcinoma

MicroRNAs (miRs) play crucial roles in the carcinogenesis and malignant progression of human cancers including nasopharyngeal carcinoma (NPC). In this study, we aimed to investigate the association of serum miR-663 levels with the clinical factors and prognosis of NPC patients. Real-time PCR was performed to examine the amount of miR-663 in serum in NPC patients and healthy controls. Our data showed that the amount of miR-663 in serum was significantly higher in NPC patients than in healthy controls. Moreover, the serum levels of miR-663 were significantly correlated with the grade, lymph node metastasis, and clinical stage of NPC. Furthermore, higher serum miR-663 levels were closely associated with worse 5-year overall survival (OS) and relapse-free survival (RFS) of patients with NPC, and the serum level of miR-663 was found to be an independent predicator for the prognosis of NPC. In addition, after receiving chemoradiotherapy, the serum levels of miR-663 were significantly reduced in NPC patients. In summary, miR-663 was upregulated in the serum of NPC patients, which was downregulated after chemoradiotherapy, and its increased levels were closely associated with malignant progression and poor prognosis in NPC patients. Therefore, the amount of miR-663 in serum may become a potential predicator for the clinical outcome of NPC patients.