Inhibition of LncRNA FOXD3-AS1 suppresses the aggressive biological behaviors of thyroid cancer via elevating miR-296-5p and inactivating TGF-β1/Smads signaling pathway

LINC00092 Enhances LPP Expression to Repress Thyroid Cancer Development via Sponging miR-542-3p

LINC00092 is poorly expressed in Thyroid cancer (TC), while its role in TC tumorigenesis is still elusive. This study aimed to reveal the role and regulatory mechanism of LINC00092 in TC.RNA immunoprecipitation and dual luciferase reporter assays were employed to ascertain the relationships among lipoma preferred partner (LPP), miR-542-3p, and LINC00092. qRT-PCR analysis was performed to detect their expression levels in TC. LPP protein productions were evaluated via western blotting. CCK-8, transwell, and colony formation assays were done to estimate TC cells' biological functions. A murine xenograft model was built to observe tumor formation in vivo.LINC00092 overexpression decreased the expression levels of miR-542-3p, and LPP was targeted by miR-542-3p. In TC cells and tissues, the elevation of miR-542-3p, and low amounts of LINC00092 and LPP can be observed. Both LINC00092 and SPAG6 were considered as the antineoplastic factors in TC since their overexpression dramatically repressed TC cells' invasive and proliferative potentials, while miR-542-3p exerted the opposite functions in TC. The ectopic expression of LINC00092 also suppressed tumor growth in vivo. In addition, it revealed that miR-542-3p upregulation reversed LINC00092 overexpression-mediated effects on TC cells. At the same time, the enhanced influences of TC cells caused by miR-542-3p upregulation could be attenuated by the enforced LPP.This study innovatively reveals that LINC00092 acts as an antineoplastic lncRNA to restrain the development of TC via regulating miR-542-3p/LPP. The findings of this study may provide a prospective drug target on LINC00092/miR-542-3p/LPP axis for the treatment of TC.

LncRNA ARAP1-AS1 targets miR-516b-5p/PDE5A axis to facilitate the progression of thyroid cancer

Thyroid cancer (TC) remains a prevalent public health concern. To further study the molecular mechanism of TC development, we explored the regulatory mechanism and function of lncRNA ARAP1-AS1 in TC progression. The verification of ARAP1-AS1, PDE5A and miR-516b-5p expression levels among the TC cell lines and tissues was fulfilled via RT-qPCR and western blot analyses. Cell Counting Kit-8 and colony formation experiments were executed to assess ARAP1-AS1's biological function in vitro. Western blotting was conducted to assess apoptosis through the expressions of apoptotic markers. A tumor xenograft experiment was conducted to evaluate whether ARAP1-AS1 affected TC tumor development in vivo . The interactions of miR-516b-5p with ARAP1-AS1 and PDE5A were explored through a dual-luciferase reporter and RNA Binding Protein Immunoprecipitation assays, as well as through Pearson's correlation analysis. ARAP1-AS1 and PDE5A were evidently upregulated in the TC cell lines and tissues whereas miR-516b-5p was poorly expressed. ARAP1-AS1 silencing in TC cells hampered cell proliferation, reduced their viability and boosted apoptosis. Moreover, it inhibited tumor growth in vivo . ARAP1-AS1 had been revealed to be correlated negatively to miR-516b-5p. Finally, we demonstrated that the miR-516b-5p inhibitor was capable of reversing ARAP1-AS1-knockdown's repressive effects on TC cell development by means of regulating PDE5A expression. ARAP1-AS1 partially facilitated TC cell development and survival through the modulation of miR-516b-5p/PDE5A axis. This contributes a novel biomarker and new perspectives for TC treatment.

Roles of TGF‑β signalling pathway‑related lncRNAs in cancer (Review)

Long non-coding RNAs (lncRNAs) are a class of RNAs that are >200 nucleotides in length that do not have the ability to be translated into protein but are associated with numerous diseases, including cancer. The involvement of lncRNAs in the signalling of certain signalling pathways can promote tumour progression; these pathways include the transforming growth factor (TGF)-β signalling pathway, which is related to tumour development. The expression of lncRNAs in various tumour tissues is specific, and their interaction with the TGF-β signalling pathway indicates that they may serve as new tumour markers and therapeutic targets. The present review summarized the role of TGF-β pathway-associated lncRNAs in regulating tumorigenesis in different types of cancer and their effects on the TGF-β signalling pathway.

Prognostic and predictive value of a lncRNA signature in patients with stage II colon cancer

The current staging method is inadequate to identify high-risk recurrence patients with stage II colon cancer (CC). Using a systematic and comprehensive-biomarker discovery and validation method, we aimed to construct a lncRNA-based signature to improve the prognostic prediction of stage II CC. We identified 1,377 differently expressed lncRNAs by analyzing 16 paired stage II CC tumor tissue and adjacent normal mucosal tissue from the TCGA dataset. Subsequently, using a univariable and step multivariable Cox regression model, we trained an 11-lncRNA signature in the training cohort (n = 141), which could divide patients into high-risk and low-risk groups (AUC at 3 years = 0.801, 95% CI: 0.724-0.877; AUC at 5 years = 0.801, 95% CI: 0.718-0.885). Significantly, patients in the high-risk group had poorer recurrence-free survival (RFS) compared with the low-risk group (log-rank test, P < 0.001 in the training cohort). This lncRNA-based signature was further confirmed in the validation cohort (P < 0.001). Multivariate Cox regression and stratified survival analyses showed that the prognostic value of this signature was independent of other clinicopathological risk factors (CEA, T stage, and chemotherapy). Time-dependent receiver operating characteristic (ROC) analysis demonstrated that this signature had better prognostic ability than any other clinical risk factors or single lncRNAs (all P < 0.05). A nomogram was constructed for clinical use, which integrated both the lncRNA-based signature and clinical risk factors (CEA and T stage) and performed well in the calibration plots. Altogether, our lncRNA-based signature was an independent prognostic factor and possessed a stronger predictive power compared with the currently used clinicopathological risk factors when predicting the recurrence of patients with stage II CC. Collectively, this lncRNA-based signature might facilitate individualized treatment decisions and postoperative counseling, ultimately contributing to improved survival.

Downregulated HDAC3 or up-regulated microRNA-296-5p alleviates diabetic retinopathy in a mouse model

Objective

It has been demonstrated the efficacy of histone deacetylase 3 (HDAC3) in diabetes. Nevertheless, the function of HDAC3 in diabetic retinopathy (DR) remained largely obscure. Here, we investigated the HDAC3 effects in DR mice through the microRNA (miR)-296-5p/G protein subunit alpha i2 (GNAI2) axis.

Methods

The mice diabetes model was established. HDAC3, GNAI2 and miR-296-5p levels in retina tissues of DR mice were evaluated. The weight, blood glucose, Evans blue leakage in DR mice, apoptosis of retinal ganglion cells, vascular endothelial growth factor (VEGF) and malondialdehyde (MDA) contents and superoxide dismutase (SOD) activity in DR mice were detected after miR-296-5p elevation or HDAC3 depletion. The relations among HDAC3, miR-296-5p and GNAI2 were validated.

Results

HDAC3 and GNAI2 expressed at a high level while miR-296-5p expressed at a low level in retina tissues of DR mice. Restoring miR-296-5p or depleting HDAC3 reduced Evans blue leakage in DR mice, attenuated apoptosis of retinal ganglion cells, reduced VEGF and MDA, and enhanced SOD activity in serum and retinal tissues of DR mice. HDAC3 repressed miR-296-5p expression by binding to its promoter region, thereby enhancing GNAI2 expression.

Conclusion

Depleting HDAC3 or restoring miR-296-5p suppresses apoptosis of retinal ganglion cells of DR mice via down-regulating GNAI2.

Identification of Paxillin as a Prognostic Factor for Glioblastoma via Integrated Bioinformatics Analysis

Glioblastoma (GBM) is the most prevalent and aggressive type of brain tumor in the central nervous system. Clinical outcomes for patients with GBM are unsatisfactory. Here, we aimed to identify novel, reliable prognostic factors for GBM. Cox and interactive analyses were used to identify hub genes from The Cancer Genome Atlas and the Chinese Glioma Genome Atlas datasets. After validation using various cohorts, survival analysis, meta-analysis, and prognostic analysis were performed. Coexpression and enrichment analyses were performed to elucidate the biological pathways of hub genes involved in GBM. ESTIMATE and CIBERSORT methods were applied to analyze the association of hub genes with the tumor microenvironment (TME). Paxillin (PXN) was identified as a hub gene with a high expression in GBM. PXN expression was negatively correlated with overall survival, progression-free survival, and disease-free survival in patients with GBM. Meta-analysis and Cox analysis revealed that PXN could act as an independent prognostic factor in GBM. In addition, PXN was significantly coexpressed with signal transducer and activator of transcription 3 and transforming growth factor β1 and participated in focal adhesion, extracellular matrix/receptor interactions, and the phosphatidylinositol 3-kinase/AKT signaling pathway. The results of ESTIMATE and CIBERSORT analyses revealed that PXN was implicated in TME alterations, particularly the infiltration of regulatory T cells, activated memory T cells, and activated natural killer cells. PXN may be a reliable prognostic factor for GBM. Further studies are needed to validate these findings.

Cancer stem cell-like cells-derived exosomal CDKN2B-AS1 stabilizes CDKN2B to promote the growth and metastasis of thyroid cancer via TGF-β1/Smad2/3 signaling

As CDKN2B-AS1 is demonstrated to exert promotive effects on thyroid cancer (TC), this research aims to investigate the role of cancer stem cell-like cells (CSCs)-derived exosomal CDKN2B-AS1 in TC and the underlying regulatory mechanism. Specifically, CDKN2B expression and the correlation of CDKN2B with CDKN2B-AS1 in TC were determined via bioinformatics analysis and further verified by qRT-PCR. After transfection or co-culture with CSCs-derived exosomes, viability, migration, and invasion of TPC-1 and SW579 cells were evaluated by CCK-8, wound healing, and transwell assays, respectively. The uptake of exosomes by TC cells was detected by PKH67 labeling. In vivo tumor formation and metastasis models were established. Tumor volume and weight were calculated. Metastasis loci in lung tissues were observed by hematoxylin-eosin staining. The expression levels of CDKN2B-AS1, CDKN2B, and epithelial-mesenchymal transition- and TGF-β1/Smad2/3 signaling-related factors were detected by qRT-PCR or Western blot. Concretely, CDKN2B and CDKN2B-AS1 were highly expressed in TC, and there was a positive correlation between the two. In addition, CDKN2B-AS1 promoted the translation and stability of CDKN2B. Furthermore, CDKN2B-AS1 was highly expressed in CSCs and CSCs-derived exosomes which could be absorbed by TC cells. CDKN2B silencing inhibited viability, migration, invasion, protein levels of CDKN2B, N-cadherin and Vimentin, and TGF-β1/Smad2/3 signaling, while promoting E-cadherin expression in TC cells. CSCs-derived exosomal CDKN2B-AS1 did oppositely and reversed the effects of CDKN2B silencing on TC cells. CDKN2B silencing impeded tumor growth and metastasis in TC mice, while TGF-β1 performed inversely and impaired the effects of CDKN2B silencing. Collectively, CSCs-derived exosomal CDKN2B-AS1 stabilizes CDKN2B to promote growth and metastasis of TC via TGF-β1/Smad2/3 signaling.

Emerging Roles and Mechanisms of lncRNA FOXD3-AS1 in Human Diseases

Numerous long noncoding RNAs (lncRNAs) have been identified as powerful regulators of human diseases. The lncRNA FOXD3-AS1 is a novel lncRNA that was recently shown to exert imperative roles in the initialization and progression of several diseases. Emerging studies have shown aberrant expression of FOXD3-AS1 and close correlation with pathophysiological traits of numerous diseases, particularly cancers. More importantly, FOXD3-AS1 was also found to ubiquitously impact a range of biological functions. This study aims to summarize the expression, associated clinicopathological features, major functions and molecular mechanisms of FOXD3-AS1 in human diseases and to explore its possible clinical applications.

Oncogenic Forkhead box D3 antisense RNA 1 promotes cell survival and confers temozolomide resistance in glioblastoma cells through the miR-128-3p/WEE1 G2 checkpoint kinase axis

Although temozolomide (TMZ) is recommended for glioblastoma (GBM) treatment, patients treated with TMZ usually develop TMZ resistance. Thus, there is an urgent need to elucidate the mechanism through which GBM cells acquire TMZ resistance. FOXD3-AS1, a recently discovered lncRNA, shows high expression in diverse cancer types. Nonetheless, its role in GBM remains unclear. This study found that FOXD3-AS1 was overexpressed in GBM cells and associated with dismal prognostic outcome in GBM patients. Functional studies revealed that depletion of FOXD3-AS1 inhibited cell growth and induced apoptosis of GBM cells. Results also showed that FOXD3-AS1 participates in the tolerance of GBM cells to TMZ. Specifically, TMZ-resistant cells exhibited higher FOXD3-AS1 expression compared to parental cells. Overexpression of FOXD3-AS1 increased TMZ tolerance in TMZ sensitive cells, whereas depletion of FOXD3-AS1 sensitized TMZ-resistant cells to TMZ treatment. Mechanistically, WEE1 was positively expressed with FOXD3-AS1. Given that both FOXD3-AS1 and WEE1 contain a binding site for miR-128-3p, FOXD3-AS1 could act as a competing endogenous RNA (ceRNA) to promote WEE1 expression by sponging miR-128-3p. Furthermore, we demonstrated that WEE1 was upregulated in TMZ-resistant GBM cells. Overexpression of WEE1 increased TMZ tolerance in TMZ sensitive cells, whereas deletion of FOXD3-AS1 promoted TMZ-resistant cells to be more sensitive to TMZ. Importantly, depletion of WEE1 could reverse TMZ resistant phenotype in FOXD3-AS1-overexpressed GBM cells. Collectively, our findings reveal a critical role of FOXD3-AS1 in the survival of GBM cells and TMZ resistance, which suggests that FOXD3-AS1 is a potential biomarker for the diagnosis and treatment of GBM.

Exosomal lncRNA FOXD3-AS1 upregulates ELAVL1 expression and activates PI3K/Akt pathway to enhance lung cancer cell proliferation, invasion, and 5-fluorouracil resistance

Long non-coding RNA (lncRNA) FOXD3-AS1 expression is upregulated in lung cancer; however, its effect and mechanism on 5-fluorouracil (5-FU) resistance remain unclear. In this study, we determined the effects of FOXD3-AS1-enriched exosomes derived from lung cancer cells on the proliferation, invasion, and 5-FU resistance of lung cancer cells. Online bioinformatics database analysis showed that FOXD3-AS1 was upregulated in lung cancer progression. Real-time quantitative PCR results confirmed that FOXD3-AS1 expression was upregulated in lung cancer tissues and cell lines, and FOXD3-AS1 was greatly enriched in lung cancer cell-derived exosomes. ELAV-like RNA-binding protein 1 (ELAVL1) was identified as an RNA-binding protein of FOXD3-AS1. The lung cancer cell-derived exosomes promoted A549 cell proliferation and invasion and inhibited apoptosis caused by 5-FU, and transfection of si-FOXD3-AS1 or si-ELAVL1 in exosome-incubated A549 cells reversed these effects. Moreover, exosome-incubated A549 cells were co-transfected with si-FOXD3-AS1 and pcDNA-ELAVL1, showing the same cell proliferation, invasion, and 5-FU resistance as those of A549 cells treated with lung cancer cell-derived exosomes alone. Mechanistic studies identified that lung cancer cell-derived exosomes activated the PI3K/Akt pathway, and transfection of si-FOXD3-AS1 or treatment with the PI3K inhibitor LY294002 reversed the activation of the PI3K/Akt axis induced by exosomes. In conclusion, our study revealed that lung cancer cell-derived exosomal FOXD3-AS1 upregulated ELAVL1 expression and activated the PI3K/Akt pathway to promote lung cancer progression. Our findings provide a new strategy for lung cancer treatment.

lncRNA FOXD3-AS1 promotes the progression of non-small cell lung cancer by regulating the miR-135a-5p/CDK6 axis

Long non-coding RNA (lncRNA) is essential to the development and progression of malignant human cancer. Growing evidence suggests that the lncRNA forkhead box D3 antisense 1 (FOXD3-AS1) is a crucial regulatory effector for multiple cancer types and is closely associated with poor prognosis. However, in most cases, the molecular mechanism underlying the role of FOXD3-AS1 in cancer development has not yet been fully elucidated. The present study focused on non-small cell lung cancer (NSCLC) in order to gain insight into how FOXD3-AS1 drives cancer progression. First, FOXD3-AS1 expression in NSCLC tissue samples was detected using reverse transcription-quantitative (RT-qPCR). Moreover, cell proliferation and apoptosis were determined using Cell Counting Kit-8 assays and flow cytometry, respectively. A luciferase reporter assay was then performed to determine whether there was a direct binding association between FOXD3-AS1 and microRNA (miR)-135a-5p. Lastly, a tumor subcutaneous xenograft model was established to examine the role of FOXD3-AS1 in tumor growth. FOXD3-AS1 was significantly overexpressed in NSCLC tissue samples and cell lines compared with normal tissue samples and cells. FOXD3-AS1 silencing expression significantly inhibited A549 and H1229 cell proliferation while inducing apoptosis compared with sh-NC group. The luciferase reporter assay demonstrated the direct binding interaction between FOXD3-AS1 and miR-135a-5p. Moreover, FOXD3-AS1 silencing led to the upregulation of miR-135a-5p in A549 and H1229 cells compared with sh-NC group. It was also demonstrated that miR-135a-5p could bind to the 3′ untranslated region of cyclin-dependent kinase 6 (CDK6) and negatively modulate its transcription. miR-135a-5p knockdown or CDK6 overexpression reversed the inhibition on cell proliferation and apoptosis following FOXD3-AS1 knockdown. Altogether, the present study suggests that FOXD3-AS1 sponges miR-135a-5p to promote cell proliferation and concomitantly inhibit apoptosis by regulating CDK6 expression in NSCLC cells.

Long non-coding RNA FOXD3 antisense RNA 1 augments anti-estrogen resistance in breast cancer cells through the microRNA-363/ trefoil factor 1/ phosphatidylinositol 3-kinase/protein kinase B axis

Long non-coding RNA (lncRNA) FOXD3 antisense RNA 1 (FOXD3-AS1) has been reported to participate in multiple processes that contribute toward the development of cancer. The present study aimed to explore the effect of lncRNA FOXD3-AS1 on anti-estrogen resistance in breast cancer (BC) cells. FOXD3-AS1 was found to be highly expressed in BC cell lines. Moreover, FOXD3-AS1 was highly expressed in estrogen receptor-negative (ER^-) cells compared to the ER-positive (ER⁺) cells. FOXD3-AS1 overexpression in T47D and MCF-7 (ER⁺) cells enhanced the resistance of cells to tamoxifen (TMX), whereas FOX3-AS1 downregulation reduced the TMX resistance in MDA-MB-231 (ER^-) cells. Similar results were reproduced in vivo that FOXD3-AS1 inhibition reduced the growth of xenograft tumors formed by MDA-MB-231 cells following TMX treatment whereas FOXD3-AS1 overexpression in T47D cells facilitated tumor growth. The bioinformatic analysis and luciferase assays indicated that FOXD3-AS1 sponged microRNA-363 (miR-363) to restore expression of trefoil factor 1 (TFF1) mRNA. Overexpression of miR-363 reduced T47D cell proliferation induced by FOXD3-AS1, whereas overexpression of TFF1 restored growth of MDA-MB-231 cells reduced after FOXD3-AS1 silencing. The phosphorylation of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) was increased by FOXD3-AS1 but attenuated by miR-363. Inhibition of PI3K/Akt blocked the role of FOXD3-AS1 and reduced the TMX resistance in T47D and MCF-7 cells. Taken together, the present study suggested that FOXD3-AS1 sponges miR-363 to upregulate TFF1 expression, leading to PI3K/Akt signaling activation and anti-estrogen resistance in BC cells.

LncRNA FOXD3-AS1 Promotes the Malignant Progression of Nasopharyngeal Carcinoma Through Enhancing the Transcription of YBX1 by H3K27Ac Modification

BACKGROUND

Long noncoding RNAs (lncRNAs) can affect the progression of various tumors, including nasopharyngeal carcinoma (NPC). Here, lncRNA FOXD3-AS1 is highly expressed in NPC tissues through bioinformatics analysis and related to the malignant progression of NPC.

METHODS

Bioinformatics analysis and real-time reverse transcription quantitative PCR(RT-qPCR) assay were applied to identify the expression of FOXD3-AS1 in NPC tissues and cells. Specific short hairpin RNAs (shRNAs) or overexpression plasmids were used to knockdown or upregulate FOXD3-AS1 in NPC cells. The effect of FOXD3-AS1 on proliferation and metastasis of NPC was confirmed by CCK8, colony formation, transwell assays in vitro and mouse tumor growth and metastasis models in vivo, of which the mechanism was explored by RNA pull down, mass spectrometry (MS), RNA Immunoprecipitation (RIP), chromatin immunoprecipitation (CHIP) and luciferase assays.

RESULTS

FOXD3-AS1 was highly expressed in NPC tissues and cells. Knockdown of FOXD3-AS1 significantly inhibited proliferation, migration, and invasion of NPC cells in vitro and vivo. FOXD3-AS1 could specifically bind to YBX1 and have a positive effect on the expression of YBX1. Bioinformatics analysis showed that the promoter of YBX1 had a high enrichment of H3K27ac, which promote mRNA transcription and protein translation of YBX1. Moreover, overexpression of YBX1 could reverse the proliferation, migration and invasion arrest caused by FOXD3-AS1 knockdown.

CONCLUSION

LncRNA FOXD3-AS1 is highly expressed and promotes malignant phenotype in NPC, which may provide a new molecular mechanism for NPC.

Upregulation of FTX expression is associated with a poor prognosis and contributes to the progression of thyroid cancer

The dysregulated expression of long non-coding RNA FTX transcript X inactive specific transcript regulator (FTX) has been reported to be involved in the tumorigenesis of multiple cancer types. However, to the best our knowledge, its function and clinical value in thyroid cancer remain unclear. The present study aimed to determine the potential role of FTX in the development and progression of thyroid cancer. Reverse transcription-quantitative PCR analysis revealed that the expression levels of FTX were upregulated in thyroid cancer tissues and cell lines compared with those in normal tissues and cell lines, respectively. Survival analysis demonstrated that patients with upregulated FTX expression had a lower survival rate. Functional experiments revealed that the knockdown of FTX inhibited proliferation, cell cycle progression, migration and invasion, and induced apoptosis in thyroid cancer cells, while FTX overexpression accelerated proliferation, migration and invasion, and alleviated apoptosis in thyroid cancer cells. In addition, FTX knockdown significantly inhibited tumor growth in vivo. Furthermore, in thyroid cancer cells, FTX was identified to positively regulate the expression levels of TGF-β1, which is known to play an important regulatory role in tumor metastasis. In conclusion, the findings of the present study suggested that FTX may accelerate thyroid cancer progression via regulation of cellular activities, including cell proliferation, migration, invasion and apoptosis. Thus, FTX may represent a potential biomarker for the diagnosis, treatment and prognosis of thyroid cancer.

Long Noncoding RNA GAS5 Targeting miR-221-3p/Cyclin-Dependent Kinase Inhibitor 2B Axis Regulates Follicular Thyroid Carcinoma Cell Cycle and Proliferation

INTRODUCTION

Follicular thyroid carcinoma (FTC) is more aggressive than the most common papillary thyroid carcinoma (PTC). However, the current research on FTC is less than PTC. Here, we investigated the effects of long noncoding RNA (lncRNA) GAS5 and miR-221-3p in FTC.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to detect GAS5 and miR-221-3p expression in the FTC tissues and cells. Cell proliferation was assessed by CCK8 and EdU assays. Flow cytometry was performed to determine the cell cycle. The dual-luciferase reporter assay was employed to validate the binding relationship of GAS5/miR-221-3p and miR-221-3p/cyclin-dependent kinase inhibitor 2B (CDKN2B). Western blot was conducted to measure the protein level of CDKN2B.

RESULTS

Our results displayed that GAS5 was downregulated, while miR-221-3p was upregulated in FTC tissues and cells. What's more, overexpression of GAS5 or miR-221-3p inhibition induced G0/G1 phase arrest and inhibited cell proliferation of FTC cells. GAS5 acted as a sponge of miR-221-3p, and CDKN2B was a target gene of miR-221-3p. Additionally, GAS5 inhibited cell cycle and proliferation of FTC cells via reducing miR-221-3p expression to enhance CDKN2B expression.

CONCLUSION

GAS5 induced G0/G1 phase arrest and inhibited cell proliferation via targeting miR-221-3p/CDKN2B axis in FTC. Thus, GAS5 may be a potential therapeutic target for the treatment of FTC.

Epigenetic regulation of papillary thyroid carcinoma by long non-coding RNAs

Thyroid cancer is the most common primary endocrine malignancy with papillary thyroid carcinoma (PTC) its most common subtype. The jump in diagnoses over last many years has prompted re-assessment of molecularly targeted therapies and the discovery of novel targets. Long non-coding RNAs (lncRNAs) are increasingly being assessed for their expression in various PTC models. Interestingly, in addition to cell line models, a large proportion of the reported studies have evaluated lncRNA levels in PTC patient samples providing an immediate clinical relevance of their findings. While most lncRNAs either promote or suppress PTC pathogenesis, data on individual lncRNAs is not very clear. As expected, lncRNAs function in PTC through sponging of microRNAs as well as modulation of several signaling pathways. The process of epithelial-mesenchymal transition and the PI3K/Akt and wnt signaling pathways have emerged as the primary targets of lncRNAs in PTC. This comprehensive review discusses all the information that is available on lncRNAs in PTC, ranging from in vitro and in vivo findings to the possible role of lncRNAs as diagnostic and/or prognostic biomarkers.

LINC01315 promotes the aggressive phenotypes of papillary thyroid cancer cells by sponging miR-497-5p

Dysregulation of the long intergenic noncoding RNA 01315 (LINC01315) has recently been demonstrated in cancer. However, the role of LINC01315 in papillary thyroid cancer (PTC) has not been determined. We attempted to determine the function of LINC01315 in PTC. The levels of LINC01315 were higher in thyroid carcinoma tissues and cell lines compared with that in noncancerous tissues or normal cells, respectively. LINC01315 knockdown significantly inhibited the in vitro colony formation and invasion of PTC cells. Upregulation of LINC01315 produced opposite effects. Bioinformatic analysis and luciferase reporter assays indicated direct binding of miR-497-5p to LINC01315. Gain- and loss-of-function assays indicated that miR-497-5p acts as a suppressive miRNA in PTC. Furthermore, LINC01315 facilitated the growth and invasion of PTC cells by sponging miR-497-5p. Our results demonstrated the critical role of the LINC01315-miR-497-5p axis in the growth and invasion of PTC cells.

LncRNA LINC00342 contributes to the growth and metastasis of colorectal cancer via targeting miR-19a-3p/NPEPL1 axis

Background

Long intergenic non-protein coding RNA 00342 (LINC00342) has been identified as a novel oncogene. However, the functional role of LINC00342 in colorectal cancer (CRC) remains unclear.

Methods

The expression of LINC00342 is detected by real-time PCR (RT-PCR) analysis. Cell proliferation, migration and invasion and xenograft model are examined to analyze the biological functions of LINC00342 in vitro and in vivo using colony formation, would healing and transwell analyses. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays are used to identify the target interactions between LINC00342, miR-19a-3p and aminopeptidase like 1 (NPEPL1).

Results

LINC00342 was highly expressed in CRC. Down-regulation of LINC00342 inhibited cell proliferation and metastasis of CRC cells. Moreover, knocking down LINC00342 inhibited the tumor growth in vivo. Mechanistic investigation revealed that LINC00342 might sponge miR-19a-3p to regulate NPEPL1 expression. Further investigation indicated that the ontogenesis facilitated by LINC00342 was inhibited due to the depletion of NPEPL1.

Conclusion

LINC00342 promotes CRC progression by competitively binding miR-19a-3p with NPEPL1.

Circ_0067835 Knockdown Enhances the Radiosensitivity of Colorectal Cancer by miR-296-5p/IGF1R Axis

Background

Colorectal cancer (CRC) is one of the most common malignant cancers globally. Circular RNAs (circRNAs) have been implicated in the development of CRC. In this paper, we set to explore the precise action of circ_0067835 in CRC progression and radioresistance.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to evaluate the expression of circ_0067835, microRNA-296-5p (miR-296-5p) and insulin-like growth factor 1 receptor (IGF1R). Western blot was used to measure the level of IGF1R protein. Cell proliferation, cell cycle distribution and apoptosis were determined by Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry and caspase-3 activity assays, respectively. The direct relationship between miR-296-5p and circ_0067835 or IGF1R was verified by dual-luciferase reporter assays. Additionally, in vivo assays were applied to confirm the role of circ_0067835 in vivo.

Results

Exosomal circ_0067835 was upregulated in the serum of CRC patients after radiotherapy. Exosome-mediated circ_0067835 knockdown repressed cell proliferation, cell cycle progression, and enhanced cell apoptosis and radiosensitivity in vitro. Circ_0067835 sponged miR-296-5p to regulate IGF1R expression in CRC cells. Moreover, the knockdown of circ_0067835 regulated CRC cell behaviors by up-regulating miR-296-5p and down-regulating IGF1R in vitro. Furthermore, circ_0067835 knockdown diminished tumor growth and promoted cell radiosensitivity in vivo.

Conclusion

Circ_0067835 knockdown suppressed CRC progression and enhanced CRC cell radiosensitivity partially by the miR-296-5p/IGF1R axis. The findings established a rationale that targeting circ_0067835 might be a promising point for improving CRC treatment.

LncRNA TINCR favors tumorigenesis via STAT3-TINCR-EGFR-feedback loop by recruiting DNMT1 and acting as a competing endogenous RNA in human breast cancer

The long noncoding RNA (lncRNA) TINCR has recently been found to be associated with the progression of human malignancies, but the molecular mechanism of TINCR action remains elusive, particularly in breast cancer. The oncogenic role of TINCR was examined in vitro and in vivo in breast cancer. Next, the interaction between TINCR, DNMT1, and miR-503-5p methylation was explored. Moreover, the mechanism by which TINCR enhances EGFR expression and downstream signaling via an RNA–RNA interaction was comprehensively investigated. Furthermore, upstream transcriptional regulation of TINCR expression by STAT3 was examined by performing chromatin immunoprecipitation. Finally, feedback signaling in the STAT3–TINCR–EGFR downstream cascade was also investigated. TINCR is upregulated in human breast cancer tissues, and TINCR knockdown suppresses tumorigenesis in vitro and in vivo. Mechanistically, TINCR recruits DNMT1 to the miR-503-5p locus promoter, which increases the methylation and suppresses the transcriptional expression of miR-503-5p. Furthermore, TINCR also functions as a competing endogenous RNA to upregulate EGFR expression by sponging miR-503-5p. In addition, TINCR stimulates JAK2–STAT3 signaling downstream from EGFR, and STAT3 reciprocally enhances the transcriptional expression of TINCR. Our findings broaden the current understanding of the diverse manners in which TINCR functions in cancer biology. The newly identified STAT3–TINCR–EGFR-feedback loop could serve as a potential therapeutic target for human cancer.

Long noncoding RNA ZFAS1 silencing alleviates rheumatoid arthritis via blocking miR-296-5p-mediated down-regulation of MMP-15

Rheumatoid arthritis (RA), a chronic inflammatory disease, deprives patients' walking ability and reduces their life quality worldwide. Though recent studies have indicated the role of long noncoding RNA (lncRNA) ZFAS1 in several diseases, however, its role in RA remains uncharacterized. The present study aimed to unravel the the effect of ZFAS1 on RA. Herein, the RA mouse model and the human RA synoviocyte MH7A cell lines stimulated with TNF-α were established. ZFAS1 was next determined to be highly expressed in the mice with RA-like symptoms and TNF-α-stimulated MH7A cells while inhibiting ZFAS1 was demonstrated to promote proliferation and suppress apoptosis of MH7A cells. Furthermore, ZFAS1 knockdown exerted anti-inflammation effect in vitro and in vivo and reduced the arthritis index value. Moreover, RNA immunoprecipitation and dual-luciferase reporter assays identified the binding of ZFAS1 to microRNA (miR)-296-5p as well as the binding of miR-296-5p to matrix metalloproteinase-15 (MMP-15). Of note, ZFAS1 could bind miR-296-5p to up-regulate the expression of MMP-15. Our results from in vitro and in vivo experiments demonstrated silencing ZFAS1 mitigated RA-like symptoms such as inflammation and hyperplasia via miR-296-5p-dependent inhibition of MMP-15. Taken altogether, our study confirmed that ZFAS1 involved in RA progression by competitively binding to miR-296-5p and regulating MMP-15 expression.

LncRNA FOXD3-AS1/miR-135a-5p function in nasopharyngeal carcinoma cells

This research aimed to illustrate the biological function and associated regulatory mechanism of lncRNA FOXD3-AS1 (FOXD3-AS1) in nasopharyngeal carcinoma (NPC). This research initially found that FOXD3-AS1 was obviously upregulated in NPC cell lines by quantitative reverse transcription polymerase chain reaction (qRT-PCR) detection. Next, the direct target of FOXD3-AS1 was predicted by bioinformatics and further verified by dual-luciferase reporter assay. MiroRNA-135a-5p (miR-135a-5p) was identified as the target gene of FOXD3-AS1 and down-expressed in C666-1 cells compared to NP69. In addition, function assays were conducted in C666-1 cells, including methyl tetrazolium assay, flow cytometry, Caspase3 activity detection, and western blot assay. Our results suggested that miR-135a-5p upregulation inhibited NPC cell growth, enhanced cell apoptosis, promoted Caspase3 activity, increased cleaved-Caspase3, and reduced pro-Caspase3 level. Moreover, we found that FOXD3-AS1 knockdown notably inhibited C666-1 cell proliferation, increased cell apoptosis, enhanced Caspase3 activity, enhanced cleaved-Caspase3 expression, and suppressed pro-Caspase3 level in C666-1 cells. However, these findings were reversed in C666-1 cells by miR-135a-5p mimic co-transfection. To sum up, our data showed that FOXD3-AS1 knockdown regulated cell growth and apoptosis in NCP cells via altering miR-135a-5p expression, suggesting that FOXD3-AS1 might be a therapeutic target for NPC diagnosis and treatment.

Identification of key genes in lung adenocarcinoma based on a competing endogenous RNA network

Lung adenocarcinoma (LUAD) is the most commonly diagnosed type of lung cancer and exhibits a high morbidity. The present study aimed to investigate the long non-coding RNA (lncRNA)-associated competing endogenous RNA (ceRNA) mechanisms in LUAD. The receptor activity modifying protein 2-antisense RNA 1 (RAMP2-AS1) was identified using GSE113852 and GSE130779 datasets downloaded from the Gene Expression Omnibus database, and the downregulation of RAMP2-AS1 was the most significant in LUAD. In addition, microRNA (miR)-296-5p was identified to bind to RAMP2-AS1 via bioinformatics analysis. Subsequently, CD44, cyclin D3 (CCND3), neurocalcin δ (NCALD), microtubule actin crosslinking factor 1 (MACF1) and potassium channel tetramerization domain containing 15 were obtained by intersecting the predicted target genes of miR-296-5p and 368 differentially expressed mRNAs in LUAD. According to the Gene Expression Profiling Interactive Analysis and UALCAN databases, these five mRNAs were downregulated in LUAD, and their expression levels were positively correlated with those of RAMP2-AS1. CD44, CCND3, NCALD and MACF1 were selected as key mRNAs in LUAD based on prognostic analyses. Furthermore, functional enrichment analyses were performed and an interaction network was constructed to reveal the functions of the RAMP2-AS1-associated ceRNA in LUAD. The results indicated that the functions were mainly enriched in generic transcription pathways, cyclin D-associated events in G₁ and epithelial stromal transformation. Reverse transcription-quantitative PCR assays revealed that RAMP2-AS1, CD44, CCND3, NCALD and MACF1 expression was lower in tumor tissues than in normal tissues, while miR-296-5p expression was higher in tumor tissues compared with in normal tissues. The association between RAMP2-AS1 and MACF1 was further confirmed using in vitro experiments. Overall, the present results indicated that RAMP2-AS1, miR-296-5p, CD44, CCND3, NCALD and MACF1 may be involved in LUAD progression and may therefore serve as potential biomarkers and provide a theoretical basis for the study of the pathogenesis of LUAD.

LncRNA FOXD3-AS1 knockdown protects against cerebral ischemia/reperfusion injury via miR-765/BCL2L13 axis

AIMS

Long non-coding RNAs (lncRNAs) FOXD3-AS1 was reported to be increased in cardiomyocyte ischemic injury. However, its role and underlying molecular mechanism in ischemic stroke remain unknown. This study was to investigate the role of FOXD3-AS1 in cerebral ischemia/reperfusion injury.

METHODS

The expression of FOXD3-AS1 and miR-765 were measured with qRT-PCR. The shared putative miR-765 binding sites both in BCL2L13 and FOXD3-AS1 were identified with bioinformatics, luciferase reporter assay and RNA immunoprecipitation. Apoptosis and its related proteins were detected by TUNEL assay, Hoechst 33,258 staining, flow cytometry and western blot. Infarct volume and the neurological status were evaluated with TTC staining and neurologic deficit score, respectively.

RESULTS

The up-regulation of FOXD3-AS1 and down-regulation of miR-765 were found in both mouse brains after cerebral ischemia/reperfusion (I/R) and neuroblastoma cells of neuro-2A (N2a) after oxygen-glucose deprivation/reoxygenation (OGD/R). Moreover, the overexpression of miR-765 reduced N2a cell apoptosis caused by OGD/R. MiR-765 could target BCL2L13 directly. In addition, we found that FOXD3-AS1 bound to miR-765 directly, acting as a ceRNA to modulate the expression of BCL2L13. Overexpression of FOXD3-AS1 antagonized the inhibitory impact of miR-765 on the expression of BCL2L13 and the apoptosis of N2a cells treated with OGD/R, while FOXD3-AS1 knockdown promoted the inhibitory impact of miR-765 on the expression of BCL2L13 and the apoptosis of N2a cells treated with OGD/R. Furthermore, we found that neurological deficits and brain injury induced by I/R in vivo were attenuated by FOXD3-AS1 knockdown.

CONCLUSIONS

We verified a critical signaling pathway of FOXD3-AS1/miR-765/BCL2L13 in regulating cerebral ischemia/reperfusion injury.

Long non-coding RNA DLEUI promotes papillary thyroid carcinoma progression by sponging miR-421 and increasing ROCK1 expression

We investigated the role of long non-coding RNA DLEU1 (deleted in lymphocytic leukemia 1) in the progression of papillary thyroid carcinoma (PTC). DLEU1 levels were higher in PTC cell lines (BHP5-16, TPC-1,8505C, and SW1736) and patient tissues (n=54) than in a human thyroid follicular epithelial cell line (Nthy-ori3-1) or adjacent normal thyroid tissues. High DLEU1 expression correlated positively with lymph node metastasis and advanced clinical stages in PTC patients. Bioinformatics, dual luciferase reporter, and RNA pulldown assays confirmed that DLEU1 directly binds to miR-421. Moreover, bioinformatics and dual luciferase reporter assays showed that miR-421 directly binds to the 3'untranslated region of the rho-related coiled-coil kinase 1 (ROCK1) in TPC-1 cells. PTC patient tissues and cell lines showed high ROCK1 mRNA and protein levels as well as low miR-421 levels. CCK-8, flow cytometry, wound healing, and Transwell invasion assays demonstrated that DLEU1 silencing decreases TPC-1 cell proliferation, survival and progression, but they can be rescued by miR-421 knockdown or ROCK1 overexpression. DLEU1 knockdown in TPC-1 cells decreased in vivo xenograft tumor size and weight compared to controls in nude mice. These findings demonstrate that DLEU1 promotes PTC progression by sponging miR-421 and increasing ROCK1 expression.

EIF5A2 Is Highly Expressed in Anaplastic Thyroid Carcinoma and Is Associated With Tumor Growth by Modulating TGF- Signals

Anaplastic thyroid carcinoma (ATC) is resistant to standard therapies and has no effective treatment. Eukaryotic translation initiation factor 5A2 (EIF5A2) has shown to be upregulated in many malignant tumors and proposed to be a critical gene involved in tumor metastasis. In this study, we aimed to investigate the expression status of EIF5A2 in human ATC tissues and to study the role and mechanisms of EIF5A2 in ATC tumorigenesis in vitro and in vivo. Expression of EIF5A2 protein was analyzed in paraffin-embedded human ATC tissues and adjacent nontumorous tissues (ANCT) (n=24) by immunochemistry. Expressions of EIF5A2 mRNA and protein were analyzed in fresh-matched ATC and ANCT (n=23) and ATC cell lines by real-time polymerase chain reaction (PCR) and Western blotting. The effect of targeting EIF5A2 with short hairpin RNA (shRNA) or EIF5A2 overexpression on the ATC tumorigenesis and TGF-/Smad2/3 signals in vitro and in vivo was investigated. Expression of EIF5A2 was significantly upregulated in ATC tissues and cell lines compared with ANCT and normal follicular epithelial cell line. Functional studies found that targeting EIF5A2 induced SW1736 cell death in vitro and in vivo, followed by significantly downregulated phosphorylation of Smad2/3 (p-Smad2/3) in SW1736 cells at the protein level. Ectopic expression of EIF5A2 could promote 8505C cell growth in vitro and in vivo, followed by significantly upregulated p-Smad3 at the protein level. Recombinant human TGF-1 (hTGF-1) treatment decreased the antiproliferative activity of the EIF5A2 downexpressing 8505C cells through reversing pSmad2/3. Using the specific inhibitor SB431542 to block TGF- pathway or Smad3 siRNA to knock down Smad3 increased the antiproliferative activity of the EIF5A2-overexpressing 8505C cells through inhibiting pSmad2/3. Our findings indicated that EIF5A2 controled cell growth in ATC cells, and EIF5A/TGF-/Smad2/3 signal may be a potential therapeutic target for ATC treatment.

FOXD3-AS1 Knockdown Suppresses Hypoxia-Induced Cardiomyocyte Injury by Increasing Cell Survival and Inhibiting Apoptosis via Upregulating Cardioprotective Molecule miR-150-5p In Vitro

Congenital heart disease (CHD) is the most common type of human innate malformation in fetuses. LncRNAs have been pointed to play critical regulatory roles in various types of cardiac development and diseases including CHD. Our study aimed to explore the effects of lncRNA forkhead box D3 antisense RNA 1 (FOXD3-AS1) on hypoxia-induced injury in AC16 cardiomyocytes and the related molecular mechanism. In vitro cell model of CHD was established by stimulating AC16 cells with hypoxia (1% O₂). Expression of FOXD3-AS1 and miR-150-5p was detected by qRT-PCR. Hypoxia-induced injury was evaluated by detecting cell survival, lactate dehydrogenase (LDH) release, apoptosis, and caspase-3/7 activity using MTT, LDH assay, flow cytometry analysis, and caspase-3/7 activity assay, respectively. The regulatory relationship between FOXD3-AS1 and miR-150-5p was explored by luciferase reporter assay, RNA immunoprecipitation (RIP), and qRT-PCR. Results showed that hypoxia exposure caused an upregulation of FOXD3-AS1 and a downregulation of miR-150-5p in AC16 cells. Knockdown of FOXD3-AS1 attenuated reduction of cell survival and increase of LDH release, apoptosis, caspase-3/7 activity, and Bcl-2 associated X (Bax) expression induced by hypoxia in AC16 cells. Notably, we demonstrated that FOXD3-AS1 directly interacted with miR-150-5p to inhibit its expression. miR-150-5p knockdown reinforced the reduction of survival and induction of apoptosis by hypoxia and attenuated the effects of FOXD3-AS1 silencing on the same parameters in AC16 cells. In conclusion, FOXD3-AS1 knockdown protected AC16 cardiomyocytes from hypoxia-induced injury by increasing cell survival and inhibiting apoptosis through upregulating miR-150-5p.

Long non-coding RNA FOXD3-AS1 regulates the expression and secretion of IL-25 in nasal epithelial cells to inhibit Th2 type immunoreaction in allergic rhinitis

Long non-coding RNA FOXD3-AS1 is associated with allergic rhinitis (AR). This article aims to demystify the role of FOXD3-AS1 in AR. We compared FOXD3-AS1 expression in nasal mucosas between AR patients and healthy control. Next, nasal epithelial cells (NECs) were incubated with lipopolysaccharide or recombinant IL-25, and then the supernatant of the NECs was incubated with CD4⁺ T cells. Th2 cell proportions were assessed by flow cytometry. The levels of gene and cytokines were detected by real-time quantitative PCR or enzyme linked immunosorbent assay. FOXD3-AS1 was downregulated in nasal mucosas of AR patients, whereas Th2 cell proportions and the levels of IL-25, IL-4, and IL-13 were enhanced in peripheral blood of AR patients. FOXD3-AS1 overexpression inhibited the expression and secretion of IL-25 in NECs. The levels of IL-4 and IL-13 and Th2 cell proportions in CD4⁺ T cells were enhanced by recombinant IL-25, which was effectively abolished by the supernatant of FOXD3-AS1-overexpressed NECs treatment. Our study demonstrates that FOXD3-AS1 is downregulated in nasal mucosas of AR patients, and FOXD3-AS1 represses the expression and secretion IL-25 in NECs, thereby inhibiting Th2 type immunoreaction in AR. Thus, our data provide a novel target gene for AR treatment.

Long noncoding RNA SNHG22 increases ZEB1 expression via competitive binding with microRNA-429 to promote the malignant development of papillary thyroid cancer

Long noncoding RNA termed small nucleolar RNA host gene 22 (SNHG22) is a crucial regulator in epithelial ovarian carcinoma. Nevertheless, the regulatory functions of SNHG22 in papillary thyroid cancer (PTC) progression and its mechanisms of action remain poorly defined. Therefore, the present study aimed to investigate the role of SNHG22 in the malignant phenotype of PTC and determine whether SNHG22 regulates PTC progression via a ceRNA mechanism. SNHG22 expression in PTC was detected using reverse transcription-quantitative polymerase chain reaction analysis. The biological actions of SNHG22 silencing in PTC cells were evaluated both in vitro (using Cell Counting Kit-8 assay, flow cytometry analysis, and cell migration and invasion assays) and in vivo (using tumorigenicity assay). Herein, high SNHG22 expression was observed in PTC tissues and cell lines. This high SNHG22 level was closely associated with unfavorable clinicopathological characteristics and worse overall survival in patients with PTC. SNHG22 knockdown effectively suppressed PTC cell proliferation, migration, and invasion in vitro; accelerated cell apoptosis; and hindered tumor growth in vivo. Mechanistic experiments revealed that SNHG22 directly interacts with microRNA-429 (miR-429) as an miRNA sponge and positively modulates ZEB1 expression. Rescue assays found that miR-429 inhibition or ZEB1 upregulation can offset the actions of SNHG22 knockdown in PTC cells. In sum, SNHG22, miR-429, and ZEB1 form an interactive regulatory network with cancer-promoting roles in PTC cells, suggesting that the SNHG22/miR-429/ZEB1 pathway is a novel diagnostic and therapeutic target.