Silence of lncRNA ANRIL represses cell growth and promotes apoptosis in retinoblastoma cells through regulating miR-99a and c-Myc

Toxicity of superparamagnetic iron oxide nanoparticles on retinoblastoma mitochondria

PURPOSE

Retinoblastoma (RB) is one of the most important cancers in children with a higher rate of prevalence in developing countries. Despite different approaches to the treatment of RB, it seems necessary to discover a new approach to its treatment. Today, mitochondria are recognised as an important target in the treatment of cancer. Superparamagnetic iron oxide nanoparticles (SPIONs) have been studied by researchers due to their important biological effects.

METHODS

In this study, the effects of SPIONs on mitochondria isolated from Y79 retinoblastoma cells were investigated.

RESULTS

The results showed that SPIONs were able to increase the reactive oxygen species (ROS) level and subsequently damage the mitochondrial membrane and release cytochrome c a as one of the important pro-apoptotic proteins of RB mitochondria. Furthermore, the results indicated a decrease in cell viability and an increase in caspase-3 activity in Y79 retinoblastoma cells.

CONCLUSIONS

These events can lead to the killing of cancerous mitochondria. Our results suggest that SPIONs can cause mitochondrial dysfunction and death in RB mitochondria.

LncRNA EIF1AX-AS1 promotes endometrial cancer cell apoptosis by affecting EIF1AX mRNA stabilization

Long non-coding RNAs (lncRNAs) have been found to play an important role in the occurrence and development of endometrial carcinoma (EC). Here, using RNA sequencing analysis, we systemically screened and identified the lncRNA EIF1AX-AS1, which is aberrantly down-regulated in clinical EC tissues and closely correlated with tumor type. EIF1AX-AS1 markedly inhibited EC cell proliferation and promoted apoptosis in vitro and in vivo. Mechanistically, EIF1AX-AS1 interacts with EIF1AX mRNA and poly C binding protein 1 (PCBP1), which promote eukaryotic translation initiation factor 1A, X-linked (EIF1AX) mRNA degradation. Intriguingly, interaction with IRES-related proteins Y-box binding protein 1 (YBX-1), EIF1AX promotes c-Myc translation through the internal ribosome enter site pathway. c-Myc promotes EIF1AX transcription and thus forms a feed-forward loop to regulate EC cell proliferation. Taken together, these data reveal new insights into the biology driving EC proliferation and highlights the potential of lncRNAs as biomarkers for prognosis and future therapeutic targets for cancer.

Long non-coding RNA PROX1-AS1 knockdown upregulates microRNA-519d-3p to promote chemosensitivity of retinoblastoma cells via targeting SOX2

OBJECTIVE

Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) participate in tumor progression, while the role of PROX1-antisense RNA1 (PROX1-AS1) sponging miR-519d-3p in retinoblastoma (RB) remains largely unknown. We aim to explore the effect of the PROX1-AS1/miR-519d-3p/sex determining region Y-box 2 (SOX2) in chemosensitivity of RB cells.

METHODS

Expression of PROX1-AS1, miR-519d-3p and SOX2 in RB tissues and cells was determined. The drug-resistant cell lines were established and respectively intervened with PROX1-AS1 or miR-519d-3p expression to explore their roles in drug resistance and malignant behaviors of the drug-resistant cells. The binding relationships between PROX1-AS1 and miR-519d-3p, and between miR-519d-3p and SOX2 were evaluated.

RESULTS

PROX1-AS1 and SOX2 were upregulated while miR-519d-3p was downregulated in RB tissues and cells, especially in drug-resistant cells. The PROX1-AS1 inhibition or miR-519d-3p elevation suppressed the drug resistance, proliferation, migration and invasion, and promoted apoptosis of the drug-resistant RB cells. Moreover, PROX1-AS1 sponged miR-519d-3p and miR-519d-3p targeted SOX2.

CONCLUSION

PROX1-AS1 knockdown upregulates miR-519d-3p to promote chemosensitivity of RB cells via targeting SOX2.

Long non-coding RNA RP11-490M8.1 inhibits lipopolysaccharide-induced pyroptosis of human umbilical vein endothelial cells via the TLR4/NF-κB pathway

BACKGROUND AND AIMS

Pyroptosis is a relatively newly discovered form of programmed cell death that plays an important role in the development of atherosclerosis. Many studies have reported that lncRNAs participated in the regulation of atherosclerosis development. However, the regulatory mechanism of lncRNAs in pyroptosis must be studied further.

METHODS

In a previous study, microarray analysis was used to detect the lncRNA expression profile in three human advanced atherosclerotic plaques and three normal arterial intimae. In the present research, in vitro assays were performed to investigate the role of lncRNA RP11-490M8.1 on pyroptosis. The relative gene mRNA and lncRNA expression levels were tested by quantitative real-time PCR, and protein levels were evaluated by western blot analysis. The RNA hybrid structure was analyzed using the DINAMelt server.

RESULTS

The lncRNA RP11-490M8.1 was significantly downregulated in atherosclerotic plaques and serum. Lipopolysaccharide (LPS) markedly reduced the expression of lncRNA RP11-490M8.1 and induced pyroptosis by increasingthe mRNA and protein levels of NLRP3, caspase-1, ASC, IL-1β, and IL-18 in HUVECs. The promotion effects ofLPS on pyroptosis were markedly suppressed by overexpression of lncRNA RP11-490M8.1. In addition, LPS increased the mRNA and protein levels ofTLR4 and NF-κB, which was also markedly offsetby overexpression of lncRNA RP11-490M8.1.

CONCLUSIONS

These findings indicated that lncRNA RP11-490M8.1 inhibited LPS-induced pyroptosis via the TLR4/NF-κB pathway. Thus, lncRNA RP11-490M8.1 may provide a therapeutic target to ameliorate atherosclerosis.

LncRNA CCAT1 sponges miR-218-5p to promote EMT, cellular migration and invasion of retinoblastoma by targeting MTF2

Retinoblastoma (RB) is the primary neoplasms of the retina that is most common in pediatrics age. Long non-coding RNAs (lncRNAs) has been noticed for strong relation to the occurrence and progress of retinoblastoma. Previously, we have demonstrated that lncRNA colon cancer-associated transcript 1 (CCAT1) in two RB cell lines SO-RB50 and Y79 was obviously overexpressed, and notably, lncRNA CCAT1 attenuated miR-218-5p expressionand induced proliferation, cell migration and invasion. But, how lncRNA CCAT1 acts in RB development and the potential molecular mechanisms remain to be determined. In this study, the expression levels of lncRNA CCAT1 and miR-218-5p were evaluated in RB tissues by Q-PCR, which established the results in the cell lines. Further, lncRNA CCAT1 was shown to promote epithelial-to-mesenchymal transition (EMT), cellular migration and invasion of RB cells by functional analysis of downregulation and overexpression of lncRNA CCAT1 with specific siRNA and pcDNA transfection. By performing bioinformatics and dual luciferase reporter assay, we verified the direct interaction between lncRNA CCAT1 and miR-218-5p. Besides, bioinformatics analysis indicated that metal regulatory transcription factor 2 (MTF2) might be a potent novel target for miR-218-5p, which was further validated with luciferase reporter assay, Q-PCR and also Western blot analysis. Functional analysis and rescue analysis showed that lncRNA CCAT1 via competitive binding to miR-218-5p to modulate MTF2 expression thus accelerate EMT, cell migration and invasion of RB. In conclusion, here we identified the lncRNA CCAT1/miR-218-5p/MTF2 axis in RB cell lines. Our investigations on the function of lncRNA CCAT1 and the roles of the related molecules hint a novel potential target fo RB therapy.

Long Noncoding RNA TRPM2-AS Promotes the Growth, Migration, and Invasion of Retinoblastoma via miR-497/WEE1 Axis

Long noncoding RNAs (lncRNAs) exhibit vital roles in many types of cancer, including retinoblastoma (RB), the most common primary intraocular malignancy tumor of infancy. A novel lncRNA TRPM2-AS has been demonstrated to be related to multiple cancers; however, its role in RB remains unclear. Here, we aimed to investigate the function of TRPM2-AS in RB. In this study, TRPM2-AS expression in 35 human RB tissues and RB cell lines was detected by real-time PCR. And, the relationship between its expression and clinicopathological characteristics of RB patients was analyzed. RB cells’ proliferation, migration, invasion, apoptosis, and cell cycle were explored after silencing TRPM2-AS. The mechanism of TRPM2-AS in RB was focused on miR-497/WEE1 axis. Additionally, the role and mechanism of TRPM2-AS were confirmed in a xenograft mouse model. We found TRPM2-AS expression was enhanced in RB tissues and cells. And, higher TRPM2-AS expression was related to advanced clinical stage and optic nerve invasion in patients. Downregulation of TRPM2-AS significantly inhibited proliferation, migration, and invasion, elevated apoptosis, attenuated G2/M phase arrest in RB cells, and suppressed tumor growth in vivo. TRPM2-AS acted as a ceRNA for miR-497 to positively regulate WEE1 expression. miR-497 inhibitor or WEE1 overexpression dramatically reversed the effects of TRPM2-AS downregulating on the malignant phenotypes of RB cells. Therefore, TRPM2-AS is an oncogenic lncRNA in RB, and it functions largely through the miR-497/WEE1 pathway. Despite the limited sample size, this study indicates that TRPM2-AS may be a candidate target in RB therapies.

Upregulating the Expression of LncRNA ANRIL Promotes Osteogenesis via the miR-7-5p/IGF-1R Axis in the Inflamed Periodontal Ligament Stem Cells

Background

Long non-coding RNA (lncRNA) antisense non-coding RNA in the INK4 locus (ANRIL) is a base length of about 3.8 kb lncRNA, which plays an important role in several biological functions including cell proliferation, migration, and senescence. This study ascertained the role of lncRNA ANRIL in the senescence and osteogenic differentiation of inflamed periodontal ligament stem cells (iPDLSCs).

Methods

Healthy periodontal ligament stem cells (hPDLSCs) and iPDLSCs were isolated from healthy/inflamed periodontal ligament tissues, respectively. The proliferation abilities were determined by CCK-8, EdU assay, and flow cytometry (FCM). The methods of Western blot assay (WB), quantitative real-time polymerase chain reaction (qRT-PCR), alizarin red staining, alkaline phosphatase (ALP) staining, ALP activity detection, and immunofluorescence staining were described to determine the biological influences of lncRNA ANRIL on iPDLSCs. Senescence-associated (SA)-β-galactosidase (gal) staining, Western blot analysis, and qRT-PCR were performed to determine cell senescence. Dual-luciferase reporter assays were conducted to confirm the binding of lncRNA ANRIL and miR-7-5-p, as well as miR-7-5p and insulin-like growth factor receptor (IGF-1R).

Results

HPDLSCs and iPDLSCs were isolated and cultured successfully. LncRNA ANRIL and IGF-1R were declined, while miR-7-5p was upregulated in iPDLSCs compared with hPDLSCs. Overexpression of ANRIL enhanced the osteogenic protein expressions of OSX, RUNX2, ALP, and knocked down the aging protein expressions of p16, p21, p53. LncRNA ANRIL could promote the committed differentiation of iPDLSCs by sponging miR-7-5p. Upregulating miR-7-5p inhibited the osteogenic differentiation of iPDLSCs. Further analysis identified IGF-1R as a direct target of miR-7-5p. The direct binding of lncRNA ANRIL and miR-7-5p, miR-7-5p and the 3′-UTR of IGF-1R were verified by dual-luciferase reporter assay. Besides, rescue experiments showed that knockdown of miR-7-5p reversed the inhibitory effect of lncRNA ANRIL deficiency on osteogenesis of iPDLSCs.

Conclusion

This study disclosed that lncRNA ANRIL promotes osteogenic differentiation of iPDLSCs by regulating the miR-7-5p/IGF-1R axis.

The Role of Noncoding RNAs in the Regulation of Anoikis and Anchorage-Independent Growth in Cancer

Cancer is a global health concern, and the prognosis of patients with cancer is associated with metastasis. Multistep processes are involved in cancer metastasis. Accumulating evidence has shown that cancer cells acquire the capacity of anoikis resistance and anchorage-independent cell growth, which are critical prerequisite features of metastatic cancer cells. Multiple cellular factors and events, such as apoptosis, survival factors, cell cycle, EMT, stemness, autophagy, and integrins influence the anoikis resistance and anchorage-independent cell growth in cancer. Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), are dysregulated in cancer. They regulate cellular signaling pathways and events, eventually contributing to cancer aggressiveness. This review presents the role of miRNAs and lncRNAs in modulating anoikis resistance and anchorage-independent cell growth. We also discuss the feasibility of ncRNA-based therapy and the natural features of ncRNAs that need to be contemplated for more beneficial therapeutic strategies against cancer.

LncRNA Linc-PINT inhibits miR-523-3p to hamper retinoblastoma progression by upregulating Dickkopf-1 (DKK1)

Emerging evidences indicated that long non-coding RNAs (LncRNAs) regulated the pathogenesis of retinoblastoma (RB). However, up until now, the role of LncRNA Linc-PINT in the regulation of RB progression is still largely unknown. The present study identified LncRNA Linc-PINT as a tumor suppressor to hinder RB development by regulating miR-523-3p/Dickkopf-1 (DKK1) axis. Mechanistically, Linc-PINT was low-expressed, while miR-523-3p was high-expressed in RB cells, compared to the normal retinal epithelial cells (ARPE-19). Further gain- and loss-function experiments verified that both upregulation of Linc-PINT and miR-523-3p downregulation slowed down cell growth, invasion and migration, and promoted cell apoptosis in RB cells, but Linc-PINT ablation and miR-523-3p overexpression promoted malignant phenotypes in RB cells. In addition, the dual-luciferase reporter gene system and RNA pull-down assay validated that Linc-PINT positively regulated DKK1 expressions by sponging miR-523-3p, and Linc-PINT inhibited RB progression by regulating miR-523-3p/DKK1 axis. Functionally, we found that both miR-523-3p overexpression and DKK1 silence abrogated the anti-cancer effects of overexpressed Linc-PINT on RB cells. Finally, Linc-PINT inhibited tumorigenicity of RB cells in xenograft mice models. In general, analysis of the data suggested that Linc-PINT inhibited miR-523-3p to upregulate DKK1, resulting in the inhibition of RB, and we demonstrated that Linc-PINT and miR-523-3p could be utilized as potential diagnostic and therapeutic biomarkers for RB in clinic.

Long non-coding RNA MALAT1 aggravates human retinoblastoma by sponging miR-20b-5p to upregulate STAT3

OBJECTIVE

Retinoblastoma (RB) is an uncommon childhood carcinoma of the developing retina. Long non-coding RNA (lncRNA) metastasis associated lung adenocarcinoma transcript 1 (MALAT1), microRNA-20b-5p (miR-20b-5p) and signal transducer and activator of transcription 3 (STAT3) was revealed to partake in RB. But their relationship was still to be investigated, so we intended to discuss the specific interaction of MALAT1, miR-20b-5p and STAT3 in RB.

METHODS

By RNA isolation and quantitation, we measured the MALAT1 expression in RB tissues and cell lines. Then, to determine the influence of MALAT1 on RB cells, RB cells were transfected with siRNA-MALAT1 or pcDNA-MALAT1. The interplay among MALAT1, miR-20b-5p and STAT3 were evaluated through dual luciferase reporter gene assay and RNA pull-down after RB cells treated with siRNA/pcDNA-MALAT1 or/and miR-20b-5p mimic/inhibitor. The influence of their interaction on cells was evaluated by cell counting kit-8, EdU assay and flow cytometry. Finally, the involvement of MALAT1 in tumorigenesis was elucidated in vivo.

RESULTS

Both RB tissues and cells showed highly expressed MALAT1. When MALAT1 was downregulated, RB cell proliferation was hindered and apoptosis was accelerated. MALAT1 sponged miR-20b-5p and upregulated STAT3. Silencing MALAT1 or overexpressing miR-20b-5p inhibited proliferation and promoted apoptosis in RB cells. The tumor growth of nude mice treated with siRNA-MALAT1 was inhibited.

CONCLUSION

MALAT1 could increase proliferation and reduce apoptosis by sponging miR-20b-5p to upregulate STAT3 in RB cells. Therefore, MALAT1 might be a latent target in the RB treatment.

RETRACTED: LncRNA MIR7-3HG executes a positive role in retinoblastoma progression via modulating miR-27a-3p/PEG10 axis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors since upon institutional inspection, the reproducibility of the CCK-8 assay was not sufficient and considered not to be valid and therefore could not support the conclusions of the article.

Long noncoding RNA LINC00205 enhances the malignant characteristics of retinoblastoma by acting as a molecular sponge of microRNA-665 and consequently increasing HMGB1 expression

Long intergenic non-protein-coding RNA 00205 (LINC00205) has been found to play crucial roles in hepatocellular carcinoma progression. In this study, we aimed to determine the expression pattern of LINC00205 in retinoblastoma (RB), to identify its functions in RB progression in detail, and to reveal the underlying mechanisms. Herein, we showed that LINC00205 is highly expressed in RB tissues and cell lines. The LINC00205 upregulation correlated with adverse clinicopathological parameters and shorter overall survival in patients with RB. LINC00205 depletion decreased the proliferative, migratory, and invasive abilities; promoted the apoptosis of RB cells in vitro; and impeded the tumor growth of RB cells in vivo. Mechanism investigation revealed that LINC00205 can act as a competing endogenous RNA by sponging microRNA-665 (miR-665) in RB cells, thereby upregulating miR-665's target: high-mobility group box 1 (HMGB1). Finally, rescue experiments confirmed that enhancing the miR-665-HMGB1 axis output attenuated the influence of the LINC00205 knockdown on RB cells. To sum up, the newly identified LINC00205-miR-665-HMGB1 pathway was systematically studied and may be validated as a potential target for RB diagnosis, prognosis, and therapy.

Mbd2 Mediates Retinal Cell Apoptosis by Targeting the lncRNA Mbd2-AL1/miR-188-3p/Traf3 Axis in Ischemia/Reperfusion Injury

Recent studies reported that DNA methylation was involved in retinal cell death. Methyl-CpG binding domain protein 2 (Mbd2) is one of the DNA methylation readers. Its role and mechanism of regulation remain unclear. The ischemia/reperfusion (I/R) model in mice primary culture retinal ganglion cells (RGCs) and Mbd2 knockout (Mbd2-KO) mice was used in the current study. We demonstrated that Mbd2 mediates RGC apoptosis caused by I/R injury. Mechanistically, the data suggested that Mbd2 upregulated Mbd2-associated long noncoding RNA 1 (Mbd2-AL1) via demethylation of its promoter. Furthermore, Mbd2-AL1 sponged microRNA (miR)-188-3p, thus preventing tumor necrosis factor (TNF) receptor-associated factor 3 (Traf3) downregulation and inducing RGC apoptosis. This was further demonstrated by the fact that inhibition of miR-188-3p diminished the anti-apoptosis role of Mbd2-AL1 small interfering RNA (siRNA). Finally, it showed that the apoptosis of retinal cells was attenuated, and the visual function was preserved in Mbd2-KO mice, which were associated with the Mbd2-AL1/miR-188-3p/Traf3 axis. Our present study revealed the role of Mbd2 in RGC apoptosis, which may provide a novel therapeutic strategy for retinal ischemic diseases.

Retracted Article: Long noncoding RNA ANRIL knockdown increases sensitivity of non-small cell lung cancer to cisplatin by regulating the miR-656-3p/SOX4 axis

Long noncoding RNAs (lncRNAs) are implicated in the development of chemoresistance in many cancers. However, the effect and mechanism of lncRNA antisense noncoding RNA in the INK4 locus (ANRIL) on cisplatin (CDDP) resistance in non-small cell lung cancer (NSCLC) remain unclear. The levels of ANRIL, microRNA (miR)-656-3p and sex-determining region Y-related high-mobility group box 4 (SOX4) in NSCLC tissues and cells were detected by quantitative real-time polymerase chain reaction or western blotting. Cell viability, apoptosis, migration and epithelial-to-mesenchymal transition (EMT) were assessed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT assay), flow cytometry, trans-well assays and western blotting, respectively. The xenograft model was established using CDDP-resistant NSCLC cells. The target association between miR-656-3p and ANRIL or SOX4 was validated by luciferase reporter assay and RNA immunoprecipitation. ANRIL expression was increased in CDDP-resistant NSCLC tissues and cells. Knockdown of ANRIL decreased cell viability, migration and EMT but induced apoptosis in CDDP-resistant NSCLC cells. Moreover, silencing of ANRIL reduced xenograft tumor growth in vivo. miR-656-3p was targeted by ANRIL and its exhaustion attenuated the suppressive role of ANRIL knockdown in CDDP resistance in NSCLC cells. SOX4 acted as a target of miR-656-3p and was positively regulated by ANRIL. Collectively, interference of ANRIL repressed CDDP resistance through promoting apoptosis and inhibiting cell viability, migration and EMT by up-regulating miR-656-3p and down-regulating SOX4, indicating a new target to improve the chemotherapeutic efficacy in NSCLC.

Long noncoding RNAs (lncRNAs) are implicated in the development of chemoresistance in many cancers.