The m6A reader YTHDC1-mediated lncRNA CTBP1-AS2 m6A modification accelerates cholangiocarcinoma progression

Background

Cholangiocarcinoma (CCA) is a serious malignancy originating from the bile ducts and the second most common primary liver cancer. Long non-coding RNA (lncRNA) is a functional lncRNA that plays an important role in human cancers. However, the role and underlying mechanisms of CTBP1-AS2 in CCA remain unknown.

Purpose

In this study, we investigated the functional role and mechanism of long-stranded non-coding RNA (lncRNA) C-terminal binding protein 1 antisense RNA 2 (CTBP1-AS2) in CCA progression.

Result

In the present study, the bioinformatics analysis revealed that YTHDC1 and CTBP1-AS2 were significantly upregulated, and it was confirmed in cholangiocarcinoma tissues from CCA patients. Meanwhile, we demonstrated that knockdown of YTHDC1 or lncRNA CTBP1-AS2 inhibited CCA cell proliferation, migration and invasion, blocked the cell cycle in G2/M phase and promoted apoptosis of CCA cells. In addition, lncRNA CTBP1-AS2-mediated N6-methyladenosine (m6A) methylation levels were significantly elevated in cholangiocarcinoma tissues, whereas knockdown of YTHDC1 resulted in a significant down-regulation of m6A methylation levels by lncRNA CTBP1-AS2.

Conclusion

Our results suggest that YTHDC1 affects cholangiocarcinoma progression by modifying the lncRNA CTBP1-AS2 m6A, and CTBP1-AS2 may be a promising therapeutic target for CCA.

CTBP1-AS2 promoted non-small cell lung cancer progression via sponging the miR-623/MMP3 axis

Mounting evidence indicates that lncRNAs (long noncoding RNAs) are involved in the initiation and development of tumors, including non-small cell lung cancer (NSCLC). However, the involvement of C-terminal binding protein-antisense RNA 2 (CTBP1-AS2) in NSCLC remains to be studied. RT-qPCR was carried out to detect CTBP1-AS2 and miR-623 expression in NSCLC cells and tissues. CCK-8 and flow cytometry were performed to measure cell proliferation and cell cycle progression. Luciferase reporter analysis was performed to study the potential target of CTBP1-AS2. We found that CTBP1-AS2 expression was upregulated in NSCLC cells (SPC-A1, A549, H23, and H1299) compared to 16HBE cells. We demonstrated that the CTBP1-AS2 level was higher in NSCLC specimens than in paired non-tumor specimens. Elevated expression of CTBP1-AS2 increased cell growth and induced cell cycle progression and epithelial-mesenchymal transition (EMT). We also found that ectopic expression of CTBP1-AS2 inhibited miR-623 expression. MMP3 was a direct target of miR-623, and luciferase reporter assays suggested that miR-623 overexpression suppressed the luciferase expression driven by the MMP3 wild-type reporter but not the mutant reporter. Overexpression of miR-623 suppressed MMP3 expression in A549 cells, and overexpression of CTBP1-AS2 increased MMP3 expression in A549 cells. Moreover, the miR-623 level was lower in NSCLC specimens than in paired non-tumor specimens, and CTBP1-AS2 expression was negatively correlated with miR-623 expression in NSCLC samples. Furthermore, overexpression of CTBP1-AS2 enhanced cell growth, cell cycle progression, and EMT progression by modulating MMP3 expression.

Downregulating Long Non-coding RNAs CTBP1-AS2 Inhibits Colorectal Cancer Development by Modulating the miR-93-5p/TGF-β/SMAD2/3 Pathway

Background: Colorectal cancer (CRC), the most commonly diagnosed cancer in the world, has a high mortality rate. In recent decades, long non-coding RNAs (lncRNAs) have been proven to exert an important effect on CRC growth. However, the CTBP1-AS2 expression and function in CRC are largely unknown.

Materials and Methods: The CTBP1-AS2 and miR-93-5p expression in CRC and para-cancerous tissues was detected by reverse transcription-PCR. The expression of CTBP1-AS2, miR-93-5p and the transforming growth factor-beta (TGF-β)/small mothers against decapentaplegic 2/3 (SMAD2/3) pathway was selectively regulated to study the correlation between CTBP1-AS2 expression and prognosis of patients with CRC. CRC cell proliferation, apoptosis, and invasion were measured in vivo and in vitro. In addition, bioinformatics was applied to explore the targeting relationship between CTBP1-AS2 and miR-93-5p. The targeting binding sites between CTBP1-AS2 and miR-93-5p, as well as between miR-93-5p and TGF-β, were verified by the dual-luciferase reporter assay and the RNA immunoprecipitation experiment.

Results: Compared with normal para-cancerous tissues, CTBP1-AS2 was considerably overexpressed in CRC tissues and was closely associated with worse survival of patients with CRC. Functionally, gain and loss in experiments illustrated that CTBP1-AS2 accelerated CRC cell proliferation and invasion and inhibited cell apoptosis. Mechanistically, CTBP1-AS2 regulated the malignant phenotype of tumor cells through the TGF-β/SMAD2/3 pathway. Moreover, miR-93-5p, as an endogenous competitive RNA of CTBP1-AS2, attenuated the oncogenic effects mediated by CTBP1-AS2.

Conclusion: CTBP1-AS2 promotes the TGF-β/SMAD2/3 pathway activation by inhibiting miR-93-5p, thereby accelerating CRC development.

SP1-induced upregulation of lncRNA CTBP1-AS2 accelerates the hepatocellular carcinoma tumorigenesis through targeting CEP55 via sponging miR-195-5p

As reported in many research, LncRNA CTBP1 divergent transcript (CTBP1-AS2) remarkably affects the progression of several tumors. However, the precise role and function of CTBP1-AS2 in hepatocellular carcinoma (HCC) remained unknown. We found that CTBP1-AS2 expressions were increased in HCC samples and cells. After treatment with microwave ablation (MWA), CTBP1-AS2 was distinctly up-regulated in residual HCC tissues compared with HCC samples. CTBP1-AS2 was upregulated under the induction of the nuclear transcription factor SP1. As revealed by the clinical assays, high CTBP1-AS2 expression usually related to lymph node metastasis, clinical stage and weaker prognosis specific to HCC patients. Functionally, CTBP1-AS2 knockdown suppressed HCC cells in terms of the proliferation, migration, invasion, chemotherapy resistance as well as EMT progress, but promoted apoptosis. Mechanistically, CTBP1-AS2 was a sponge of miR-195-5p for elevating CEP55 expression, a target of miR-195-5p, and thereby exhibited its oncogenic roles in HCC progression. Overall, an emerging regulatory mechanism of SP1/CTBP1-AS2/miR-195-5p/CEP55 axis was reported in the paper, which possibly served as a new therapeutic HCC treatment target.

LncRNA CTBP1-AS2 Facilitates Gastric Cancer Progression via Regulating the miR-139-3p/MMP11 Axis

Background

This study aimed at probing into the effect of long non-coding RNA (lncRNA) C-terminal binding protein 1 antisense RNA 2 (CTBP1-AS2) on gastric cancer (GC) cell proliferation and apoptosis, and its regulatory function on miR-139-3p and MMP11.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to examine the expressions of CTBP1-AS2, miR-139-3p and MMP11 mRNA in GC cell lines and clinical specimens. Cell counting kit-8 (CCK-8) assay, flow cytometry and EdU assay were conducted to examine the effects of CTBP1-AS2 and miR-139-3p on GC cell proliferation and apoptosis. Western blot was applied for detecting the expressions of Bax, Bcl-2 and MMP11. A lung metastasis mouse model was used to evaluate metastasis of GC cells in vivo. Bioinformatics, dual-luciferase report assay, RIP and RNA pull-down assays were utilized to validate the targeted relationship between CTBP1-AS2 and miR-139-3p as well as the targeting relationship between miR-139-3p and MMP11.

Results

CTBP1-AS2 was highly expressed in GC, and its high expression was strongly associated with increased TNM stage, increased tumor size and low degree of differentiation of the tumor tissues. Meanwhile, CTBP1-AS2 promoted GC cell proliferation, metastasis and suppressed apoptosis, while miR-139-3p could weaken these effects. In addition, CTBP1-AS2 was identified as a molecular sponge for miR-139-3p, and MMP11 was verified as a target gene of CTBP1-AS2. CTBP1-AS2 could increase the expression of MMP11 via repressing miR-139-3p.

Conclusion

CTBP1-AS2 promotes GC cells and inhibits apoptosis by regulating the miR-139-3p/MMP11 molecular axis.

lncRNA CTBP1-AS2 promotes proliferation and migration of glioma by modulating miR-370-3p-Wnt7a-mediated epithelial-mesenchymal transition

Glioma is one of the most common and aggressive malignant primary brain tumors, with a poor 5-year survival rate. The long noncoding RNA (lncRNA) CTBP1-AS2 has been shown to be correlated with the prognosis of cancer, but the role of CTBP1-AS2 in glioma and its concrete mechanism is fully unknown. The clinical data and tissues of glioma patients were analyzed. Cell viability and migration assays were performed. Western blotting and qRT-PCR were adopted for investigation of target protein expressions. Double luciferase assay was used to investigate the interaction between different elements. The lncRNA CTBP1-AS2 had increased expression profiles in tumor tissues, which is associated with poor prognosis. In detail, CTBP1-AS2 knockdown decreased proliferation and migration phenotypes in both U87-MG and LN229 cells. Moreover, CTBP1-AS2 knockdown suppressed the key epithelial-mesenchymal transition (EMT) markers by downregulating Wnt7a-mediated signaling. Furthermore, miR-370-3p functioned as a link that could be absorbed by CTBP1-AS2, thus regulating Wnt7a expression. Lastly, the CTBP1-AS2-miR-370-3p-Wnt7a axis modulated EMT in glioma cells in vitro and in vivo. This study provides new insights that a novel lncRNA, CTBP1-AS2, regulates EMT of glioma by modulating the miR-370-3p-Wnt7a axis.

LncRNA CTBP1-AS2 alleviates high glucose-induced oxidative stress, ECM accumulation, and inflammation in diabetic nephropathy via miR-155-5p/FOXO1 axis

BACKGROUND

This study aimed to investigate the involvement of lncRNA CTBP1-AS2 in the progression of diabetic nephropathy (DN) by affecting high glucose (HG)-induced human glomerular mesangial cells (HGMCs).

METHODS

HGMCs were selected for the establishment of cell injury induced by HG. The expression of CTBP1-AS2, miR-155-5p and FOXO1 was detected by real-time PCR and western blotting. The target association between miR-155-5p and CTBP1-AS2 or FOXO1 was confirmed by dual-luciferase reporter assays. Cell proliferation and oxidative stress were revealed by CCK-8 colorimetry, and the measurement of reactive oxygen species (ROS) and the activities of antioxidant enzymes. Extracellular matrix (ECM) protein accumulation and the production of inflammatory cytokines were investigated by western blotting and ELISA.

RESULTS

The expression of CTBP1-AS2 was downregulated, and miR-155-5p was highly expressed in peripheral blood of DN patients and HG-treated HGMCs. Further investigation revealed that CTBP1-AS2 overexpression inhibited proliferation, oxidative stress, ECM accumulation and inflammatory response in HG-induced HGMCs. Mechanical analysis revealed that CTBP1-AS2 regulated FOXO1 expression via sponging miR-155-5p. Rescue experiments demonstrated that miR-155-5p overexpression or FOXO1 inhibition reversed the effects of CTBP1-AS2 in HG-stimulated HGMCs.

CONCLUSION

Taken together, this study revealed CTBP1-AS2 attenuated HG-induced HGMC proliferation, oxidative stress, ECM accumulation, and inflammation through miR-155-5p/FOXO1 signaling.

Long non-coding RNA CTBP1-AS2 enhances cervical cancer progression via up-regulation of ZNF217 through sponging miR-3163

Background

Long non-coding RNAs (lncRNAs) play significant roles in tumorigenesis and can contribute to identification of novel therapeutic targets for cancers. This paper was aimed at exploring the role of CTBP1 divergent transcript (CTBP1-AS2) in cervical cancer (CC) progression.

Methods

qRT-PCR and western blot assays were used to detect relevant RNA and protein expressions. In vitro functional assays, including CCK8, EdU, TUNEL and transwell assays were applied to explore the functions of CTBP1-AS2 in CC cell proliferation, apoptosis and migration. In vivo animal study was utilized to investigate the role of CTBP1-AS2 in tumor growth. Luciferase reporter, RNA pull down and RIP assays were performed to determine the specific mechanical relationship between CTBP1-AS2, miR-3163 and ZNF217.

Results

CTBP1-AS2 was significantly overexpressed in CC cell lines. Knockdown of CTBP1-AS2 curbed cell proliferation, migration and invasion, while stimulated cell apoptosis in vitro. CTBP1-AS2 facilitated xenograft tumor growth in vivo. Cytoplasmic CTBP1-AS2 was found to be a miR-3163 sponge in CC cells. MiR-3163 inhibition abolished the anti-tumor effects of CTBP1-AS2 knockdown. Additionally, Zinc finger protein 217 (ZNF217) was identified as a direct target of miR-3163. CTBP1-AS2 acted as a miR-3163 sponge to elevate ZNF217 expression. ZNF217 up-regulation abrogated the tumor suppressing effects of CTBP1-AS2 knockdown.

Conclusion

CTBP1-AS2 regulates CC progression via sponging miR-3163 to up-regulate ZNF217.

LncRNA CTBP1-AS2 regulates miR-216a/ PTEN to suppress ovarian cancer cell proliferation

Background

We analyzed TCGA dataset and observed the downregulation of CTBP1-AS2 in ovarian cancer (OC), while the function of CTBP1-AS2 has only been investigated in diabetes and cardiomyocyte hypertrophy, but not in cancer biology. We therefore analyzed the involvement of CTBP1-AS2 in OC.

Result

We found that CTBP1-AS2 was downregulated in OC and predicted poor survival. CTBP1-AS2 in luciferase activity assay interacted with miR-216a, while overexpression of CTBP1-AS2 and miR-216a had no significant effects on the expression of each other. However, increased expression level of PTEN, a target of miR-216a, was observed after CTBP1-AS2 overexpression. Increased proliferation rate of OC cells was observed after the overexpression of miR-216a. CTBP1-AS2 and PTEN overexpression resulted in the reduced proliferation rate of OC cells and reduced effects of miR-216a overexpression.

Conclusion

CTBP1-AS2 regulates miR-216a/PTEN to suppress OC cell proliferation.

LncRNA CTBP1-AS2 Promotes Cell Proliferation in Hepatocellular Carcinoma by Regulating the miR-623/Cyclin D1 Axis

This study investigated the role of lncRNA CTBP1-AS2 in hepatocellular carcinoma (HCC). The authors found that CTBP1-AS2 was upregulated in HCC by analyzing TCGA dataset. The downregulation of CTBP1-AS2 in HCC was confirmed by measuring the expression level of CTBP1-AS2 in both HCC and nontumor tissues from HCC patients. MiR-623 is predicted to target CTBP1-AS2, while it failed to downregulate its expression. Interestingly, CTBP1-AS2 overexpression led to the upregulation of cyclin D1, a target of miR-623. CCK-8 analysis showed that CTBP1-AS2 and cyclin D1 overexpression promoted the proliferation of HCC cells. MiR-623 overexpression played an opposite role and reduced the effects of CTBP1-AS2 and cyclin D1 overexpression. Therefore, CTBP1-AS2 promotes cell proliferation in HCC by regulating the miR-623/cyclin D1 axis.

LncRNA CTBP1-AS2 is upregulated in osteoarthritis and increases the methylation of miR-130a gene to inhibit chondrocyte proliferation

OBJECTIVES

LncRNA CTBP1-AS2 has been reported to be involved in type 2 diabetes and cardiomyocyte hypertrophy, while its roles in other human diseases are unknown. Our preliminary deep sequencing analysis showed altered expression of CTBP1-AS2 in osteoarthritis (OA). In addition, CTBP1-AS2 was inversely correlated with miR-130a. This study was therefore carried out to investigate the interactions between CTBP1-AS2 and miR-130a in OA.

METHODS

Synovial fluid was collected from 62 OA patients and 62 healthy controls. RT-qPCR was performed to determine the expression levels of CTBP1-AS2 and miR-130a in synovial fluid. Cell transfections were performed to investigate the interactions between CTBP1-AS2 and miR-130a. Methylation-specific PCR (MSP) was performed to assess the effects of CTBP1-AS2 on the methylation of miR-130a. Cell counting Kit-8 (CCK-8) assay was performed to evaluate the roles of CTBP1-AS2 and miR-130a in regulating proliferation of chondrocytes.

RESULTS

The results showed that CTBP1-AS2 was upregulated in OA and inversely correlated with miR-130a. In chondrocytes of OA patients, overexpression of CTBP1-AS2 led to increased methylation of miR-130a gene and downregulated expression of miR-130a, while overexpression of miR-130a did not affect the expression of CTBP1-AS2. In contrast, no interaction between CTBP1-AS2 and miR-130a was observed in chondrocytes from healthy adults. Analysis of chondrocyte proliferation showed that overexpression of miR-130a led to increased proliferation rate of chondrocytes extracted from OA patients. Overexpression of CTBP1-AS2 led to decreased proliferation rate of chondrocytes and reversed the effects of overexpressing miR-130a.

CONCLUSION

Therefore, CTBP1-AS2 is upregulated in OA and may increase the methylation of miR-130a gene to inhibit chondrocyte proliferation. Key Points • CTBP1-AS2 is overexpressed in OA and may downregulate miR-130a through methylation to suppress the proliferation of chondrocytes. • The interaction between CTBP1-AS2 and miR-130a is indirect and mediated by certain pathological mediators.

LncRNA CTBP1-AS2 sponges miR-216a to upregulate PTEN and suppress endometrial cancer cell invasion and migration

Background

Although lncRNA CTBP1-AS2 has been functionally analyzed only in cardiomyocyte hypertrophy and diabetes, analysis of TCGA dataset revealed its downregulation in endometrial carcinoma (EC), indicating its involvement in EC.

Results

In this study we found that CTBP1-AS2 was downregulated in EC and correlated with poor survival. MiR-216a might form base pairs with CTBP1-AS2 based on RNA-RNA interaction, which was confirmed by luciferase activity assay. Interestingly, upregulation of PTEN was observed after CTBP1-AS2 overexpression. Transwell assay showed that CTBP1-AS2 and PTEN overexpression led to decreased cancer cell invasion and migration and reduced enhancing effects of miR-216a on cell invasion and migration. It was known that miR-216a targeted PTEN.

Conclusion

Therefore, CTBP1-AS2 may sponge miR-216a to upregulate PTEN, thereby suppressing endometrial cancer cell invasion and migration.

Sp1-induced LncRNA CTBP1-AS2 is a novel regulator in cardiomyocyte hypertrophy by interacting with FUS to stabilize TLR4

Cardiomyocyte hypertrophy is a heart response adapting to increasing cardiac load. Prolonged cardiomyocyte hypertrophy indicates a higher risk of heart failure or even cardiac death. Long noncoding RNAs have been largely reported to modulate human diseases. CTPB1-AS2 is a newly discovered lncRNA reported as an oncogene in papillary thyroid cancer, but its function in cardiomyocyte hypertrophy has never been probed. Toll-like receptor 4 (TLR4) is recognized to play important roles in cardiomyocyte hypertrophy. The present study aimed to investigate the role of CTBP1-AS2 in cardiomyocyte hypertrophy. First, we discovered the low expression of CTBP1-AS2 in normal heart tissues in GETx database. Then, we established cardiomyocyte hypertrophy models on mice and cardiomyocytes through transverse aortic constriction surgery and Ang II treatment. We revealed the up-regulation of CTBP1-AS2 and TLR4 in cardiomyocyte hypertrophy models. Also, we confirmed the positive correlation between CTBP1-AS2 and TLR4 expressions in cardiomyocyte hypertrophy tissues. Loss-of-function assays confirmed that inhibiting CTBP1-AS2 attenuated the Ang II-induced cardiomyocyte hypertrophy. Mechanism research showed that CTBP1-AS2 stabilized TLR4 mRNA by recruiting FUS. Rescue assays certified that CTBP1-AS2 regulated cardiomyocyte hypertrophy through TLR4. Finally, we found Sp1 as an upstream activator for CTBP1-AS2 expression. In conclusion, our study uncovered CTBP1-AS2 as a novel regulator of cardiomyocyte hypertrophy through regulating TLR4, providing a new potential treatment target for cardiomyocyte hypertrophy.