LncRNA MCM3AP-AS1 promotes chemoresistance in triple-negative breast cancer through the miR-524-5p/RBM39 axis

Triple-negative breast cancer (TNBC) is the most lethal subtype of BC, with unfavorable treatment outcomes. Evidence suggests the engagement of lncRNA MCM3AP-AS1 in BC development. This study investigated the action of MCM3AP-AS1 in chemoresistance of TNBC cells. Drug-resistant TNBC cell lines SUM159PTR and MDA-MB-231R were constructed by exposure to increasing concentrations of doxorubicin/docetaxel (DOX/DXL). MCM3AP-AS1 and miR-524-5p expression levels were determined by RT-qPCR. RNA binding motif 39 (RBM39) level was measured using Western blot. Cell viability and apoptosis were assessed by CCK-8 assay and flow cytometry. The targeted binding of miR-524-5p with MCM3AP-AS1 or RBM39 was predicted by ECORI database and validated by dual-luciferase assays. The gain-and-loss of function assays were conducted in cells to investigate the interactions among MCM3AP-AS1, miR-524-5p, and RBM39. TNBC xenograft mouse models were established through subcutaneous injection of MCM3AP-AS1-silencing MDA-MB-231R cells and intraperitoneally administrated with DOX/DXL to verify the role of MCM3AP-AS1 in vivo. MCM3AP-AS1 was upregulated in drug-resistant TNBC cells, and MCM3AP-AS1 silencing could sensitize drug-resistant TNBC cells to chemotherapeutic drugs by promoting apoptosis. MCM3AP-AS1 targeted miR-524-5p. After DOX/DXL treatment, miR-524-5p inhibition partially reversed the effect of MCM3AP-AS1 silencing on inhibiting chemoresistance and promoting apoptosis of drug-resistant TNBC cells. miR-524-5p targeted RBM39. Silencing MCM3AP-AS1 promoted apoptosis via the miR-524-5p/RBM39 axis, thereby enhancing chemosensitivity of drug-resistant TNBC cells. MCM3AP-AS1 knockdown upregulated miR-524-5p, downregulated RBM39, and restrained tumor development in vivo. MCM3AP-AS1 silencing potentiates apoptosis of drug-resistant TNBC cells by upregulating miR-524-5p and downregulating RBM39, thereby suppressing chemoresistance in TNBC.

BUB1, BUB1B, CCNA2, and CDCA8, along with miR-524-5p, as clinically relevant biomarkers for the diagnosis and treatment of endometrial carcinoma

BACKGROUND

Endometrial carcinoma (EC) is a malignant tumor of the female reproductive tract that has been associated with increased morbidity and mortality. This study aimed to identify biomarkers and potential therapeutic targets for EC.

METHODS

A publicly available transcriptome data set comprising 587 EC cases was subjected to a comprehensive bioinformatics analysis to identify candidate genes responsible for EC occurrence and development. Next, we used clinical samples and cell experiments for validation.

RESULTS

A total of 1,617 differentially expressed genes (DEGs) were identified. Analysis of patient survival outcomes revealed that BUB1, BUB1B, CCNA2, and CDCA8 were correlated with prognosis in patients with EC. Moreover, assessment of clinical samples confirmed that BUB1, BUB1B, CCNA2 and CDCA8 were strongly expressed in EC tissues. Additionally, bioinformatics and luciferase reporter assays confirmed that miR-524-5p can target and regulate these four genes. Overexpression of miR-524-5p significantly inhibited EC Ishikawa cells viability, migration and invasion. Inhibition of miR-524-5p showed the opposite results.

CONCLUSIONS

Expression of miR-524-5p reduced the migration and invasion of Ishikawa EC cells, and decreased BUB1, BUB1B, CCNA2, and CDCA8 expression. miR-524-5p, as well as BUB1, BUB1B, CCNA2, and CDCA8, may be clinically relevant biomarkers for the diagnosis and treatment of EC.

Long non-coding RNA nuclear enriched abundant transcript 1 (NEAT1) modulates inhibitor of DNA binding 1 (ID1) to facilitate papillary thyroid carcinoma development by sponging microRNA-524-5p

Long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) exerts a pro-oncogenic role in several cancers, whereas its underlying regulatory mechanism in papillary thyroid carcinoma (PTC) progression remains unknown. This research mainly explored the roles of NEAT1 in PTC development. Quantitative real-time polymerase-chain reaction (qRT-PCR) was applied to measure NEAT1, miR-524-5p, and inhibitor of DNA binding 1 (ID1) expression in PTC tissues and cells. Western blot was conducted for detecting the protein levels. MTT, transwell, and flow cytometry assays were applied to assess cell proliferation, metastasis, and apoptosis in PTC cells in vitro. The PTC xenograft tumor model was used for investigating the role of NEAT1 in vivo. Dual-luciferase reporter assay was utilized for confirming the interaction between miR-524-5p and NEAT1 or ID1. In PTC tissues and cells, NEAT1 was significantly up-regulated. NEAT1 silencing blocked cell proliferation, metastasis, and facilitated apoptosis in vitro and impeded xenograft tumor growth in vivo. Bioinformatics prediction revealed the existence of binding sites between NEAT1 and miR-524-5p. Besides, ID1 was confirmed as a direct target to miR-524-5p, and the enhancement of ID1 reversed the regulation of miR-524-5p upregulation on cell progression. In addition, NEAT1 promoted PTC development by regulating ID1 expression via sponging miR-524-5p in PTC. In summary, we demonstrate that NEAT1 advanced the process of PTC by miR-524-5p/ID1 axis, which may enhance our comprehension of PTC pathogenesis.

Exosome-transmitted circVMP1 facilitates the progression and cisplatin resistance of non-small cell lung cancer by targeting miR-524-5p-METTL3/SOX2 axis

Background

Circular RNAs (circRNAs) play important regulatory roles in multiple human malignancies, including non-small cell lung cancer (NSCLC). Here, we explored the role of circRNA vacuole membrane protein 1 (circVMP1) in NSCLC progression and cisplatin (DDP) resistance.

Methods

The DDP resistance, proliferation, sphere formation ability, migration, invasion, and apoptosis of NSCLC cells were analyzed by Cell Counting Kit-8 (CCK8) assay, 5-ethynyl-2′-deoxyuridine (EdU) assay, sphere formation assay, wound healing assay, Transwell assay, and flow cytometry. Methylated RIP-qPCR (MeRIP-qPCR) was conducted to analyze the m⁶A modification level of SRY-box transcription factor 2 (SOX2). Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA-pull down assay were performed to confirm the intermolecular interaction. Exosomes were identified by transmission electron microscopy (TEM) and characterized by nanoparticle tracking analysis (NTA).

Results

CircVMP1 expression was markedly elevated in DDP-resistant NSCLC cell lines compared with their parental cell lines. CircVMP1 absence restrained the proliferation, sphere formation, migration, invasion, and DDP resistance and promoted the apoptosis of DDP-resistant NSCLC cells. CircVMP1 acted as microRNA-524-5p (miR-524-5p) sponge to up-regulate the expression of methyltransferase 3, N6-adenosine-methyltransferase complex catalytic subunit (METTL3) and SOX2. CircVMP1 silencing restrained the malignant behaviors and DDP resistance of A549/DDP and H1299/DDP cells by targeting miR-524-5p. Exosomal circVMP1 disseminated the malignant properties and DDP resistance to DDP-sensitive cells. Exosomal circVMP1 elevated the DDP resistance of xenograft tumors in vivo. Exosomal circVMP1 was up-regulated in the serum samples of DDP-resistant NSCLC patients compared with DDP-sensitive patients.

Conclusion

Exosome-mediated transmission of circVMP1 promoted NSCLC progression and DDP resistance by targeting miR-524-5p-METTL3/SOX2 axis.

Highlights

CircVMP1 level is up-regulated in DDP-resistant NSCLC cell lines compared with DDP-sensitive cell lines.

CircVMP1 absence restrains the malignant behaviors and DDP resistance of A549/DDP and H1299/DDP cells.

CircVMP1-miR-524-5p/METTL3/SOX2 axis is identified for the first time.

CircVMP1 plays an oncogenic role by targeting miR-524-5p-METTL3/SOX2 axis in A549/DDP and H1299/DDP cells.

Exosomal circVMP1 transmits the malignant properties and DDP resistance to DDP-sensitive cells.

Ginsenoside Rh2 inhibits thyroid cancer cell migration and proliferation via activation of miR-524-5p

INTRODUCTION

Thyroid cancer is an important disease that threatens the health of humans. Ginsenoside Rh2 is known as an anticancer molecule; however, its function in thyroid cancer cells has not been reported. In the present study, we identified that Rh2 treatment of the thyroid cancer cell line K1 inhibited cell migration and proliferation.

MATERIAL AND METHODS

We determined the Rh2 function in thyroid cancer cell lines. By RT-PCR, expression of miR-524-5p and related genes were determined. The cell phenotype including cell migration and proliferation were detected after serials treatment. The relevant protein level were checked by Western blot.

RESULTS

Interestingly, we observed that miR-524-5p, a type of miRNA, had lower expression in the thyroid cancer cell lines TPC-1, K1, and NPA than in the normal thyroid cell line Nthyri3-1. Additionally, Rh2 treatment induced miR-524-5p expression. Further examination using overexpression of miR-524-5p identified that the miR-524-5p mimic inhibited cell migration and proliferation of the K1 line. Similar to Rh2-treated cells, the miR-524-5p mimic-expressing cells had increased E-cadherin and reduced vimentin levels compared to the control cells. Next, we examined the relationship between Rh2 and miR-524-5p with respect to thyroid cell migration and proliferation. Treatment with Rh2 and miR-524-5p inhibitor suppressed Rh2 action on K1 thyroid cell migration and proliferation, and the rates were similar to those in control cells, suggesting that Rh2 might induce miR-524-5p expression to inhibit thyroid cancer cell migration and proliferation.

CONCLUSIONS

Our analyses identified Rh2 and miR-524-5p action on thyroid cancer cell migration and proliferation as well as the linkage between Rh2 and miR-524-5p in thyroid cancer cell development.

YAP/miR-524-5p axis negatively regulates TXNIP expression to promote chondrosarcoma cell growth

Chondrosarcoma (CHS) is the second most common bone malignant tumor and currently has limited treatment options. We have recently demonstrated that thioredoxin interacting protein (TXNIP) plays a crucial role in the oncogenesis of bone sarcoma, yet its implication in CHS is underdetermined. In the present study, we first found that knockdown of TXNIP promotes the proliferation of CHS cell largely through increasing their glycolytic metabolism, which is well-known as Warburg effect for providing energy. Consistent with our previous report that YAP is fundamental for CHS cell growth, herein we revealed that YAP functioned as an upstream molecule of TXNIP, and that YAP negatively regulated TXNIP mRNA and protein expression both in vitro and in vivo. Mechanistically, although knockdown of YAP upregulated both the nuclear and cytoplasmic TXNIP expression, we did not observe any obvious interaction between YAP and TXNIP; instead, miRNA-524-5p was demonstrated to be required for YAP-regulated TXNIP expression and thus controlling CHS cell growth. Together, our study reveals that TXNIP is a tumor suppressor in terms of CHS, and that the YAP/miRNA-524-5p/TXNIP signaling axis may provide a novel clue for CHS targeted therapy.

Long noncoding RNA NEAT1 inhibits the acetylation of PTEN through the miR-524-5p /HDAC1 axis to promote the proliferation and invasion of laryngeal cancer cells

Long noncoding RNA nuclear paraspeckle assembly transcript 1 (lncRNA NEAT1) is abnormally expressed in numerous tumors and functions as an oncogene, but the role of NEAT1 in laryngocarcinoma is largely unknown. Our study validated that NEAT1 expression was markedly upregulated in laryngocarcinoma tissues and cells. Downregulation of NEAT1 dramatically suppressed cell proliferation and invasion through inhibiting miR-524-5p expression. Additionally, NEAT1 overexpression promoted cell growth and metastasis, while overexpression of miR-524-5p could reverse the effect. NEAT1 increased the expression of histone deacetylase 1 gene (HDAC1) via sponging miR-524-5p. Mechanistically, overexpression of HDAC1 recovered the cancer-inhibiting effects of miR-524-5p mimic or NEAT1 silence by deacetylation of tensin homolog deleted on chromosome ten (PTEN) and inhibiting AKT signal pathway. Moreover, in vivo experiments indicated that silence of NEAT1 signally suppressed tumor growth. Taken together, knockdown of NEAT1 suppressed laryngocarcinoma cell growth and metastasis by miR-524-5p/HDAC1/PTEN/AKT signal pathway, which provided a potential therapeutic target for laryngocarcinoma.

LINC00184 plays an oncogenic role in non-small cell lung cancer via regulation of the miR-524-5p/HMGB2 axis

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. We aimed to investigate the role of LINC00184 in NSCLC. Migration, proliferation and invasion of NSCLC cells were analysed using the wound healing assay, cell counting kit-8 assay and transwell assay, respectively. Apoptosis and cell cycle were assessed using flow cytometry. Online bioinformatics tools were utilized to predict downstream microRNAs (miRNA) or genes related to LINC00184 expression. The RNA pull-down experiment and luciferase reporter assay were performed to verify the predictions thereof. LINC00184, miR-524-5p, and high mobility group 2 protein (HMGB2) expression levels in NSCLC tissues and cell lines were detected using quantitative real-time polymerase chain reaction. An NSCLC mouse model was constructed for in vivo experiments. LINC00184 overexpression was observed in NSCLC tissues and cell lines and was found to be correlated with poor prognosis. LINC00184 knockdown inhibited cell proliferation, migration and invasion, induced cell cycle arrest and accelerated apoptosis in NSCLC cell lines. LINC00184 suppressed tumour growth and proliferation in NSCLC mouse models and directly targeted the miR-524-5p/HMGB2 axis. Moreover, the expression levels of LINC00184 and HMGB2 were negatively correlated with miR-524-5p expression, whereas LINC00184 expression was positively correlated with HMGB2 expression. LINC00184 affected the cell cycle, proliferation, apoptosis, migration and invasion in NSCLC via regulation of the miR-524-5p/HMGB2 axis.

miR-524-5p reduces the progression of the BRAF inhibitor-resistant melanoma

BRAF inhibitors were approved for the treatment of BRAF-mutant melanoma. However, most patients acquire the resistance to BRAF inhibitors after several months of treatment. miR-524-5p is considered as a tumor suppressor in many cancers, including melanoma. In this study, we investigated the biological functions of miR-524-5p in melanoma with acquired resistance to BRAF inhibitor and evaluated the endogenous miR-524-5p expression as a biomarker for melanoma. The results showed that the expression of miR-524-5p was 0.481-fold lower in melanoma tissues (n = 117) than in nevus tissues (n = 40). Overexpression of miR-524-5p significantly reduced proliferative, anchorage-independent growth, migratory and invasive abilities of BRAF inhibitor-resistant melanoma cells. Moreover, the introduction of miR-524-5p led to a reduced development of BRAF inhibitor-resistant melanoma in vivo. Remarkably, the MAPK/ERK signaling pathway was decreased after treatment with miR-524-5p. Furthermore, next-generation sequencing analysis implied that the complement system, leukocyte extravasation, liver X receptor/retinoid-X-receptor activation, and cAMP-mediated signaling may be related to miR-524-5p-induced pathways in the resistant cells. The miR-524-5p level was higher on average in complete response and long-term partial response patients than in progressive disease and short-term partial response patients treated with BRAF inhibitors. Our results proposed that miR-524-5p could be considered as a target for treatment BRAF inhibitor-resistant melanoma and a prognostic marker in the response of patients to BRAF inhibitors for melanoma.

Knockdown of circHIPK3 Facilitates Temozolomide Sensitivity in Glioma by Regulating Cellular Behaviors Through miR-524-5p/KIF2A-Mediated PI3K/AKT Pathway

Background: Temozolomide (TMZ) resistance is a serious hindrance in clinical chemotherapy for glioma. Circular RNA homeodomain interacting protein kinase 3 (circHIPK3) can be involved in regulating the progression of glioma, but the molecular mechanism of circHIPK3 in TMZ-resistant-glioma is completely unclear. Materials and Methods: The levels of circRNA, miRNA, and mRNA were examined using quantitative real-time polymerase chain reaction. 3-(4,5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide assay was used for assessing the half inhibitory concentration (IC₅₀) of TMZ and cell proliferation. Cell apoptosis and metastasis (migration and invasion) were detected by flow cytometry and transwell assay, respectively. Western blot and dual-luciferase reporter assay were performed several times to analyze the expression levels of associated proteins and the targeted relation. Results: The upregulation of circHIPK3 was found in TMZ-resistant glioma tissues and cells. Both circHIPK3 knockdown and kinesin family member 2A (KIF2A) inhibition could facilitate TMZ sensitivity and apoptosis but repress proliferation and metastasis in TMZ-resistant glioma cells. CircHIPK3 targeted microRNA-524-5p (miR-524-5p) and KIF2A functioned as a downstream target of miR-524-5p. Decrease of miR-524-5p relieved the effects of si-circHIPK3 on TMZ-resistant glioma cells by upregulating KIF2A. Downregulation of circHIPK3 refrained the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signal pathway partly through miR-524-5p/KIF2A axis. Conclusions: Knockdown of circHIPK3 promoted TMZ sensitivity in glioma by modulating proliferation, metastasis, and apoptosis through miR-524-5p/KIF2A-mediated PI3K/AKT pathway. CircHIPK3 may be the potential target for the diagnosis and therapy of TMZ-resistant glioma.

Long Noncoding RNA TP53TG1 Contributes to Radioresistance of Glioma Cells Via miR-524-5p/RAB5A Axis

Background: Long noncoding RNAs (lncRNAs) have been reported to be important regulators in cancer. In this study, we aimed to discover the functions of lncRNA TP53TG1 in glioma. Methods: The expression of lncRNA TP53TG1, microRNA-524-5p (miR-524-5p) and RAB5A, a member RAS oncogene family (RAB5A), were examined by quantitative real-time polymerase chain reaction. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were applied to analyze the proliferation and apoptosis of glioma cells. Colony formation assay was used to detect the colony formation ability and radioresistance of glioma cells. Western blot assay was performed to detect the expression of autophagy-associated proteins and RAB5A. StarBase software was utilized to predict the combination between miR-524-5p and TP53TG1 or RAB5A, and dual-luciferase reporter assay and RNA immunoprecipitation assay were used to verify the above predictions. Animal experiment using immunodeficient nude mice was conducted to detect the role of TP53TG1 in vivo. Results: Radiation stimulation (6 Gy) upregulated the abundance of TP53TG1. TP53TG1 potentiated radioresistance and progression of glioma by promoting the autophagy. miR-524-5p was verified as a direct downstream regulation of TP53TG1. miR-524-5p depletion attenuated the influence of TP53TG1 interference on the functions of glioma cells. RAB5A was a direct target of miR-524-5p as well. The inhibitory effect of miR-524-5p on the malignancy of glioma cells was overturned by overexpression of RAB5A. RAB5A was regulated by TP53TG1/miR-524-5p signaling in glioma cells. TP53TG1 silencing impeded the progression of glioma in vivo. Conclusion: lncRNA TP53TG1 accelerated the proliferation, colony formation, autophagy, and radioresistance, and restrained the apoptosis of glioma cells through miR-524-5p/RAB5A axis.

microRNA-524-5p inhibits proliferation and induces cell cycle arrest of osteosarcoma cells via targeting CDK6

BACKGROUND

Osteosarcoma (OS) is one of the most commonly diagnosed malignant tumors that mainly affects children and adolescents. The underlying molecular mechanisms that are responsible for the initiation and development of OS are still not clear. Increasing evidence suggested the tumor suppressor role of microRNA-524-5p in a variety of cancers via targeting key pathways involved in tumorigenesis. The aim of this study was to characterize the function of miR-524-5p in OS.

METHODS

A total 50 paired OS tissues and adjacent normal tissues were collected from OS patients. The expression of miR-524-5p in OS tissues and cells was detected by RT-qPCR. The CCK-8 assay, flow cytometry and transwell assay were applied to determine the proliferation and invasion abilities of OS cells. The targets of miR-524-5p were predicted using the miRDB dataset and confirmed by luciferase reporter assay and western blot analysis.

RESULTS

The expression of miR-524-5p was decreased in OS tissues and cell lines. OS patients with lymph node metastasis harbored relative lower level of miR-524-5p. Overexpression of miR-524-5p in OS cells significantly suppressed the proliferation, drove cell cycle arrest and apoptosis. The mechanism investigation revealed that miR-524-5p bound the 3'-untranslated region (UTR) of Cyclin Dependent Kinase 6 (CDK6) and repressed the expression of CDK6 in OS cells. Overexpressed CDK6 was found in OS tissues, which was inversely correlated with that of miR-524-5p. Moreover, forced expression of CDK6 significantly reversed the anti-cancer effects of miR-524-5p on the proliferation, apoptosis and cell cycle arrest of OS cells.

CONCLUSIONS

Our results identified the tumor-suppressive role of miR-524-5p in OS via targeting CDK6, which may lead to the identification of novel therapeutic target for the treatment of OS.

[LncRNA LINC-PINT regulating proliferation and apoptosis of osteosarcoma cells by targeting miR-524-5p]

Objective: To study the effect of long non-coding RNA LINC-PINT on proliferation and apoptosis of osteosarcoma cells. Methods: Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expressions of LINC-PINT and miR-524-5p in normal osteoblast hFOB and human osteosarcoma cell lines HOS, MG63 and SAOS2 cells. The pcDNA plasmid, pcDNA-LINC-PINT plasmid, negative control siRNA (si-NC), si-LINC-PINT, negative control mimics (miR-NC), miR-524-5p mimics (miR-524-5p), pcDNA-LINC-PINT combined with miR-NC, pcDNA-LINC-PINT combined with miR-524-5p were transfected into HOS cells with liposome, respectively. The protein expressions of PCNA and cleaved-caspase-3 in the cells were detected by western blot. Cell proliferation ability was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay. The apoptosis was detected by flow cytometry. The transcriptional activity was detected by double luciferase reporter assay. Results: Compared with normal osteoblast hFOB cell (1.00±0.08 vs 1.00±0.06), the expressions of LINC-PINT were down-regulated (0.18±0.01; 0.33±0.01; 0.42±0.01), while the expressions of miR-524-5p were up-regulated (2.65±0.23; 1.68±0.14; 1.51±0.13) in human osteosarcoma cell lines HOS, MG63 and SAOS2 cells, respectively. Overexpression of LINC-PINT significantly inhibited the proliferation (0.41±0.05 vs. 0.62±0.05 for 48 h; 0.57±0.05 vs. 1.06±0.09 for 72 h, both P<0.05) while promoted the apoptosis (25.28±2.15 vs. 9.01±0.17, P<0.01) of HOS cells. Knockdown of LINC-PINT or overexpression of miR-524-5p can significantly promote the proliferation and inhibit apoptosis of HOS cells. Moreover, miR-524-5p inhibited the fluorescence activity of wild-type LINC-PINT (0.31±0.03) in HOS cells when comparred with miR-NC (1.00±0.03) and was negatively regulated by LINC-PINT. Overexpression of miR-524-5p reversed the proliferation inhibition and apoptosis-promotion effects of LINC-PINT in HOS cells. Conclusions: Long non-coding RNA LINC-PINT can inhibit the proliferation and promote apoptosis of osteosarcoma cells through targeting miR-524-5p, which will provide a new target for the treatment of osteosarcoma.

LncRNA TTN-AS1 Regulates miR-524-5p and RRM2 to Promote Breast Cancer Progression

Background

Recent studies suggest many long non-coding RNAs (lncRNAs) are crucial oncogenes or tumor suppressors. This study intended to investigate the biological function and mechanism of lncRNA TTN antisense RNA 1 (TTN-AS1) in the progression of breast cancer (BC).

Materials and Methods

BC tissue samples were collected. The expression of TTN-AS1 in BC tissues and adjacent tissues was detected by qRT-PCR, and the relationship between pathological indicators and TTN-AS1 expression was analyzed by chi-square test. BC cell lines T47D and BT549 were utilized as cell models. CCK-8 assay and BrdU assay were used to detect the effect of TTN-AS1 on BC cell proliferation. Transwell assay was used to detect the effects of TTN-AS1 on cell migration and invasion. In addition, dual-luciferase reporter gene assay was used to confirm the targeting relationship between miR-524-5p and TTN-AS1. Western blot was used to detect the function of TTN-AS1 on regulating ribonucleotide reductase subunit 2 (RRM2) and survivin. Additionally, subcutaneous xenotransplanted tumor model and tail vein injection model were constructed in vivo.

Results

The expression of TTN-AS1 in BC tissues was significantly higher than that in normal tissues, and its high expression was correlated with adverse pathological indicators. Overexpression of TTN-AS1 significantly promoted the proliferation, migration and invasion of BC cells. TTN-AS1 knockdown suppressed the malignant phenotypes of BC cells. TTN-AS1 overexpression significantly impeded the expression of miR-524-5p, but increased the expression of RRM2.

Conclusion

TTN-AS1 exerts oncogenic function in BC by repressing miR-524-5p and increasing the expression of RRM2.

LncRNA MSC-AS1 aggravates nasopharyngeal carcinoma progression by targeting miR-524-5p/nuclear receptor subfamily 4 group A member 2 (NR4A2)

Background

Nasopharyngeal carcinoma (NPC) is a subtype of head and neck cancer with dismal prognosis and high relapse rate. The role of long non-coding RNAs (lncRNAs) in NPC has become a research hotspot in recent years. This study aimed to interrogate the function and mechanism of lncRNA MSC antisense RNA 1 (MSC-AS1) in NPC.

Methods

MSC-AS1 level in NPC tissues and cells were detected by RT-qPCR. Function of MSC-AS1 in NPC cells was assessed by CCK-8, EdU, TUNEL, caspase-3 activity, and transwell invasion assay. Interaction of microRNA-524-5p (miR-524-5p) with MSC-AS1 and nuclear receptor subfamily 4 group A member 2 (NR4A2) was determined by RIP and luciferase reporter assays.

Results

MSC-AS1 was upregulated in NPC tissues and cells. Functional assays indicated that MSC-AS1 exacerbated cell proliferation, hindered apoptosis, and facilitated invasion and epithelial-to-mesenchymal transition (EMT) in NPC. Mechanistically, MSC-AS1 sequestered miR-524-5p to upregulate NR4A2 expression in NPC cells. Finally, NR4A2 was conformed as an oncogene in NPC, and overexpressed NR4A2 could restore MSC-AS1 knockdown-mediated inhibition on NPC progression.

Conclusions

Our study firstly showed that lncRNA MSC-AS1 aggravated NPC progression by sponging miR-524-5p to increase NR4A2 expression, indicating MSC-AS1 as a novel target for the lncRNA-targeted therapy in NPC.

MiR-524-5p Suppresses Migration, Invasion, and EMT Progression in Breast Cancer Cells Through Targeting FSTL1

Background: The effects of miR-524-5p on breast cancer (BC) have not been investigated, though studies show that miR-524-5p has an anticancer function. Thus, this study investigated the effects of miR-524-5p on BC cells and its potential molecular mechanism. Materials and Methods: The expression of miR-524-5p from the collected BC samples was determined. Cell counting kit-8 (CCK-8) assay was performed to examine the effect of miR-524-5p on BC cells viability. The target for miR-524-5p was predicted by bioinformatics and further verified by luciferase assay. Wound healing assay and transwell assay were performed to determine cell migration and invasion of BC cells. The expressions of Follistatin-like 1 (FSTL1) and related proteins in epithelial-mesenchymal transition (EMT) were detected by Western blotting and quantitative real-time polymerase chain reaction. Results: MiR-524-5p was low-expressed in BC samples, and upregulation of miR-524-5p suppressed BC cell viability, migration, and invasion. FSTL1 was predicted as a target for miR-524-5p. In addition, overexpressed FSTL1 effectively abolished the effect of miR-524-5p on inhibiting FSTL1 expression, and reversed the inhibitory effects of miR-524-5p on the migration, invasion of BC cells as well as the effect of miR-524-5p on regulating the expressions of matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), E-cadherin, and N-cadherin. Conclusions: Our findings suggest that miR-524-5p targeting FSTL1 adversely affects the progression of migration, invasion, and EMT of BC cells, thus, miR-524-5p is possibly a target for BC treatment.

MicroRNA-524-5p suppresses the progression of papillary thyroid carcinoma cells via targeting on FOXE1 and ITGA3 in cell autophagy and cycling pathways

MicroRNAs are beneficial for cancer therapy as they can simultaneously downregulate multiple targets involved in diverse biological pathways related to tumor development. In papillary thyroid cancer, many microRNAs were identified as differentially expressed factors in tumor tissues. In another way, recent studies revealed cell proliferation, cell cycling, apoptosis, and autophagy are critical pathways controlling papillary thyroid cancer development and progression. As miR‐524‐5p was approved as a cancer suppressor targeting multiple genes in several types of cancer cells, this study aims to characterize the role of miR‐524‐5p in the thyroid cancer cell. The expression of miR‐524‐5p was decreased in the papillary thyroid cancer tissues and cell lines, while forkhead box E1 (FOXE1) and ITGA3 were increased. In the clinical case, expression of miR‐524‐5p, FOXE1, and ITGA3 were significantly correlated with papillary thyroid cancer development and progression. FOXE1 and ITGA3 were approved as direct targets of miR‐524‐5p. miR‐524‐5p could inhibit papillary thyroid cancer cell viability, migration, invasion, and apoptosis through targeting FOXE1 and ITGA3. Cell cycling and autophagy pathways were disturbed by downregulation of FOXE1 and ITGA3, respectively. Collectively, miR‐524‐5p targeting on FOXE1 and ITGA3 prevents thyroid cancer progression through different pathways including cell cycling and autophagy.

miR-524-5p of the primate-specific C19MC miRNA cluster targets TP53IPN1- and EMT-associated genes to regulate cellular reprogramming

Background

Introduction of the transcription factors Oct4, Sox2, Klf4, and c-Myc (OSKM) is able to ‘reprogram’ somatic cells to become induced pluripotent stem cells (iPSCs). Several microRNAs (miRNAs) are known to enhance reprogramming efficiency when co-expressed with the OSKM factors. The primate-specific chromosome 19 miRNA cluster (C19MC) is essential in primate reproduction, development, and differentiation. miR-524-5p, a C19MC member, is highly homologous to the reprogramming miR-520d-5p; we also reported that miR-524-5p was expressed in iPSCs but not mesenchymal stem cells (MSCs). This study aimed to elucidate possible contributions of miR-524-5p to the reprogramming process.

Methods

A miR-524-5p precursor was introduced into human fibroblast HFF-1 in the presence of OSKM, and the relative number of embryonic stem cell (ESC)-like colonies that stained positively with alkaline phosphatase (AP) and Nanog were quantified to determine reprogramming efficiency. A miR-524-5p mimic was transfected to MSCs to investigate the effects of miR-524-5p on TP53INP1, ZEB2, and SMAD4 expression by real-time polymerase chain reaction (PCR) and Western blot. Direct gene targeting was confirmed by luciferase activity. A phylogenetic tree of TP53INP1 was constructed by the Clustal method. Contribution of miR-524-5p to cell proliferation and apoptosis was examined by cell counts, BrdU, MTT, and cell death assays, and pluripotency gene expression by real-time PCR.

Results

Co-expressing the miR-524 precursor with OSKM resulted in a two-fold significant increase in the number of AP- and Nanog-positive ESC-like colonies, indicating a role for miR-524-5p in reprogramming. The putative target, TP53INP1, showed an inverse expression relationship with miR-524-5p; direct TP53INP1 targeting was confirmed in luciferase assays. miR-524-5p-induced TP53INP1 downregulation enhanced cell proliferation, suppressed apoptosis, and upregulated the expression of pluripotency genes, all of which are critical early events of the reprogramming process. Interestingly, the TP53INP1 gene may have co-evolved late with the primate-specific miR-524-5p. miR-524-5p also promoted mesenchymal-to-epithelial transition (MET), a required initial event of reprogramming, by directly targeting the epithelial-to-mesenchymal transition (EMT)-related genes, ZEB2 and SMAD4.

Conclusions

Via targeting TP53INP1, ZEB2, and SMAD4, miR-524-5p contributes to the early stage of inducing pluripotency by promoting cell proliferation, inhibiting apoptosis, upregulating expression of pluripotency genes, and enhancing MET. Other C19MC miRNAs may have similar reprogramming functions.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0666-3) contains supplementary material, which is available to authorized users.

MicroRNA-524-5p suppresses the growth and invasive abilities of gastric cancer cells

Previous studies have demonstrated that microRNAs (miRNAs) are associated with tumor development and progression. miRNA-524-5p (miR-524-5p) has been reported to be involved in the development and progression of several types of cancer, but its role in gastric cancer has not been fully elucidated to date. Therefore, the aim of the present study was to investigate the expression levels and function of miR-524-5p in human gastric cancer. The expression levels of miR-524-5p were assessed in gastric cancer specimens and cell lines, including MKN-45, SGC-7901 and MGC-803 cell lines and gastric epithelial mucosa GES-1 cells, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell proliferation and cell apoptosis assays and invasion analysis in gastric cancer cell lines were performed to evaluate the effects of miR-524-5p on gastric cancer cells in vitro. The expression levels of matrix metallopeptidase (MMP)-2 and MMP-9 were determined by RT-qPCR and western blot analysis. The expression of miR-524-5p was significantly decreased in gastric cancer tissues and cell lines. Additionally, the results of the in vitro experiments demonstrated that overexpression of miR-524-5p inhibited cell proliferation and invasion, and promoted cell apoptosis in gastric cancer cells. Human gastric cancer SGC-7901 and MGC-803 cell lines transfected with miR-524-5p exhibited reduced expression levels of MMP-2 and MMP-9. Taken together, the results of the present study indicated that miR-524-5p may function as a novel tumor suppressor gene in gastric cancer, and may serve as a biomarker and therapeutic target for the treatment of gastric cancer.