Biological function and mechanism of MALAT-1 in renal cell carcinoma proliferation and apoptosis: role of the MALAT-1-Livin protein interaction

The functions of long non-coding RNA (lncRNA)-MALAT-1 in the pathogenesis of renal cell carcinoma

Renal cell carcinoma (RCC), a prevalent form of renal malignancy, is distinguished by its proclivity for robust tumor proliferation and metastatic dissemination. Long non-coding RNAs (lncRNAs) have emerged as pivotal modulators of gene expression, exerting substantial influence over diverse biological processes, encompassing the intricate landscape of cancer development. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1), an exemplar among lncRNAs, has been discovered to assume functional responsibilities within the context of RCC. The conspicuous expression of MALAT-1 in RCC cells has been closely linked to the advancement of tumors and an unfavorable prognosis. Experimental evidence has demonstrated the pronounced ability of MALAT-1 to stimulate RCC cell proliferation, migration, and invasion, thereby underscoring its active participation in facilitating the metastatic cascade. Furthermore, MALAT-1 has been implicated in orchestrating angiogenesis, an indispensable process for tumor expansion and metastatic dissemination, through its regulatory influence on pro-angiogenic factor expression. MALAT-1 has also been linked to the evasion of immune surveillance in RCC, as it can regulate the expression of immune checkpoint molecules and modulate the tumor microenvironment. Hence, the potential utility of MALAT-1 as a diagnostic and prognostic biomarker in RCC emerges, warranting further investigation and validation of its clinical significance. This comprehensive review provides an overview of the diverse functional roles exhibited by MALAT-1 in RCC.

The Role of Long Noncoding RNA (lncRNAs) Biomarkers in Renal Cell Carcinoma

Renal cell carcinoma is one of the common cancers whose incidence and mortality are continuously growing worldwide. Initially, this type of tumour is usually asymptomatic. Due to the lack of reliable diagnostic markers, one-third of ccRCC patients already have distant metastases at the time of diagnosis. This underlines the importance of establishing biomarkers that would enable the prediction of the disease's course and the risk of metastasis. LncRNA, which modulates genes at the epigenetic, transcriptional, and post-transcriptional levels, appears promising. The actions of lncRNA involve sponging and sequestering target miRNAs, thus affecting numerous biological processes. Studies have confirmed the involvement of RNAs in various diseases, including RCC. In this review, we focused on MALAT1 (a marker of serious pathological changes and a factor in the promotion of tumorigenesis), RCAT1 (tumour promoter in RCC), DUXAP9 (a plausible marker of localized ccRCC), TCL6 (exerting tumour-suppressive effects in renal cancer), LINC00342 (acting as an oncogene), AGAP2 Antisense1 (plausible predictor of RCC progression), DLEU2 (factor promoting tumours growth via the regulation of epithelial-mesenchymal transition), NNT-AS1 (sponge of miR-22 contributing to tumour progression), LINC00460 (favouring ccRCC development and progression) and Lnc-LSG1 (a factor that may stimulate ccRCC metastasis).

Exploration of the role of Cuproptosis genes and their related long non-coding RNA in clear cell renal cell carcinoma: a comprehensive bioinformatics study

Clear cell renal cell carcinoma is a common malignant tumor of the urinary system. The mechanism of its occurrence and development is unknown, and there is currently few effective comprehensive predictive markers for prognosis and treatment response. With the discovery of a new cell death process - cuproptosis drew the attention of researchers. We constructed a model for the prediction of clinical prognosis and immunotherapy response through integrative analysis of gene expression datasets from KIRC samples in The Cancer Genome Atlas (TCGA) database. During the course of the study, we found that cuproptosis genes are significantly differentially expressed between clear cell renal cell carcinoma samples and normal samples. Based on this, we put forward the prognostic model for cuproptosis gene related-long non-coding RNA. And through various statistic and external independent cohorts, we proved that the model is accurate and stable, worthy of clinical application and further exploration and validation.

Long non-coding RNA and RNA-binding protein interactions in cancer: Experimental and machine learning approaches

Understanding the complex and specific roles played by non-coding RNAs (ncRNAs), which comprise the bulk of the genome, is important for understanding virtually every hallmark of cancer. This large group of molecules plays pivotal roles in key regulatory mechanisms in various cellular processes. Regulatory mechanisms, mediated by long non-coding RNA (lncRNA) and RNA-binding protein (RBP) interactions, are well documented in several types of cancer. Their effects are enabled through networks affecting lncRNA and RBP stability, RNA metabolism including N⁶-methyladenosine (m⁶A) and alternative splicing, subcellular localization, and numerous other mechanisms involved in cancer. In this review, we discuss the reciprocal interplay between lncRNAs and RBPs and their involvement in epigenetic regulation via histone modifications, as well as their key role in resistance to cancer therapy. Other aspects of RBPs including their structural domains, provide a deeper knowledge on how lncRNAs and RBPs interact and exert their biological functions. In addition, current state-of-the-art knowledge, facilitated by machine and deep learning approaches, unravels such interactions in better details to further enhance our understanding of the field, and the potential to harness RNA-based therapeutics as an alternative treatment modality for cancer are discussed.

Long noncoding RNA-LINC00478 promotes the progression of clear cell renal cell carcinoma through PBX3

Long noncoding RNAs play an important regulatory role in the development and progression of tumors. Our study found that LINC00478 was upregulated in clear cell renal cell carcinoma (ccRCC), so we made an in-depth exploration into its mechanism. In Caki-2 cells, we established the oe-LINC00478 cell line overexpressing LINC00478, and established underexpressing sh-LINC00478 cell line by short hairpin RNA silencing. The abilities of oe-LINC00478 cell invasion and metastasis were significantly enhanced, and the cell proliferative potential was also improved. The cellular expressions of PBX3, CDCA8, and CDK2 were upregulated, while in the sh-LINC00478 cells, the proliferative potential and metastatic and invasive abilities were weakened. Similarly, we established the PBX3-overexpressing oe-PBX3 cell line and the PBX3-underexpressing sh-PBX3 cell line, finding that the PBX3 overexpression enhanced the metastatic and invasive abilities of Caki-2 cells. When we overexpressed LINC00478 in PBX3-knockout Caki-2-PBX3^{- / -} cells, no significant changes were noted in the metastatic or invasive ability. Through RNA pull-down and RNA-binding protein immunoprecipitation assays, we found that LINC00478 could facilitate the transcription-translation processes of PBX3 by binding to it, thus further promoting the expression of downstream cyclins to exert its action. In animal experimentation, the oe-LINC00478 and sh-LINC00478 Caki-2 cells were separately seeded, revealing that the tumor volume was significantly larger in the oe-LINC00478 group than in the sh-LINC00478 group. This study finds that by promoting the PBX3 transcription, LINC00478 can further regulate the expressions of downstream cyclins, thereby facilitating the metastasis and invasion of ccRCC.

Construction of a Prognostic Model for KIRC and Identification of Drugs Sensitive to Therapies - A Comprehensive Biological Analysis Based on m6A-Related LncRNAs

As one of the common malignancies in the urinary system, kidney cancer has been receiving explorations with respect to its pathogenesis, treatment and prognosis due to its high morbidity, high mortality and low drug efficiency. Such epigenetic modifications for RNA molecules as N6-methyladenosine (m6A) usher in another perspective for the research on tumor mechanisms, and an increasing number of biological processes and prognostic markers have been revealed. In this study, the transcriptome data, clinical data and mutation spectrum data of KIRC in the TCGA database were adopted to construct an m6A-related lncRNA prognostic model. Besides, the predictive ability of this model for clinical prognosis was evaluated, and some compounds sensitive to therapies for KIRC were screened. The findings of this study demonstrate that this effective and stable model has certain clinical application value.

LncRNAs in the Regulation of Genes and Signaling Pathways through miRNA-Mediated and Other Mechanisms in Clear Cell Renal Cell Carcinoma

The fundamental novelty in the pathogenesis of renal cell carcinoma (RCC) was discovered as a result of the recent identification of the role of long non-coding RNAs (lncRNAs). Here, we discuss several mechanisms for the dysregulation of the expression of protein-coding genes initiated by lncRNAs in the most common and aggressive type of kidney cancer-clear cell RCC (ccRCC). A model of competitive endogenous RNA (ceRNA) is considered, in which lncRNA acts on genes through the lncRNA/miRNA/mRNA axis. For the most studied oncogenic lncRNAs, such as HOTAIR, MALAT1, and TUG1, several regulatory axes were identified in ccRCC, demonstrating a number of sites for various miRNAs. Interestingly, the LINC00973/miR-7109/Siglec-15 axis represents a novel agent that can suppress the immune response in patients with ccRCC, serving as a valuable target in addition to the PD1/PD-L1 pathway. Other mechanisms of action of lncRNAs in ccRCC, involving direct binding with proteins, mRNAs, and genes/DNA, are also considered. Our review briefly highlights methods by which various mechanisms of action of lncRNAs were verified. We pay special attention to protein targets and signaling pathways with which lncRNAs are associated in ccRCC. Thus, these new data on the different mechanisms of lncRNA functioning provide a novel basis for understanding the pathogenesis of ccRCC and the identification of new prognostic markers and targets for therapy.

Comprehensive analysis of lncRNAs as biomarkers for diagnosis, prognosis, and treatment response in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common histological type of renal carcinoma and has a high recurrence rate and poor outcome. Accurate patient risk stratification based on genetic markers can help to identify the high-risk patient for early and further treatments and would promote patient survival. Long non-coding RNAs (lncRNAs) have attracted widespread attention as biomarkers for early diagnosis, treatment, and prognosis because of their high specificity and sensitivity. Here, we performed a systematic search in NCBI PubMed and found 44 lncRNAs as oncogenes, 18 lncRNAs as tumor suppressors, 199 lncRNAs as diagnostic biomarkers, 62 lncRNAs as prognostic biomarkers, and 3 lncRNAs as predictive biomarkers for ccRCC. We also comprehensively discuss the biological functions and molecular regulatory mechanisms of lncRNAs in ccRCC. Overall, the present study is a systemic analysis to assess the expression and clinical value of lncRNAs in ccRCC, and lncRNAs hold promise to be diagnostic, prognostic, and predictive biomarkers.

Mechanism of tumor‑derived extracellular vesicles in regulating renal cell carcinoma progression by the delivery of MALAT1

Renal cell carcinoma (RCC) is a major healthcare burden globally. Tumor-derived extracellular vesicles (EVs) contribute to the formation of a pro-metastatic microenvironment. In the present study, we explored the role and mechanism of RCC cell 786-O-derived EVs (786-O-EVs) in RCC. First, 786-O-EVs were extracted and identified, and EV internalization of RCC cells was observed. RCC cell malignant behaviors and long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) expression patterns were detected before and after 786-O-EV treatment. MALAT1 was intervened to evaluate RCC cell behaviors. The downstream mechanism involving MALAT1 was predicted. In addition, the relationship among MALAT1, transcription factor CP2 like 1 (TFCP2L1) and ETS proto-oncogene 1, transcription factor (ETS1) was analyzed. TFCP2L1 expression patterns were measured after 786-O-EV exposure. Tumor xenograft formation assay and lung metastasis model were adopted to verify the role of 786-O-EVs in vivo in RCC. It was found that 786-O-EVs could be internalized by RCC cells. 786-O-EVs promoted RCC cell malignant behaviors, accompanied by elevated MALAT1 expression levels. The 786-O-EVs with MALAT1 knockdown attenuated the promotive effect of sole 786-O-EVs on RCC cells. MALAT1 located ETS1 in the TFCP2L1 promoter and negatively regulated TFCP2L1, and ETS1 protein could specifically bind to MALAT1. 786-O-EVs enhanced the binding of ETS1 and the TFCP2L1 promoter and decreased TFCP2L1 expression. In vivo, 786-O-EVs promoted tumor growth and RCC lung metastasis, which was suppressed following inhibition of MALAT1. Our findings indicated that 786-O-EVs promoted RCC invasion and metastasis by transporting MALAT1 to promote the binding of transcription factor ETS1 and TFCP2L1 promoter.

MALAT1 recruited the E3 ubiquitin ligase FBXW7 to induce CRY2 ubiquitin-mediated degradation and participated in trophoblast migration and invasion

This study aimed to investigate the mechanism by which MALAT1 regulates CRY2 expression and participates in trophoblast migration and invasion. Three patients with unexplained recurrent spontaneous abortion, four patients with missed abortion, and four women who underwent artificial miscarriages were enrolled in this study. Quantitative reverse-transcription polymerase chain reaction and western blot analysis were used to detect RNA and protein expression, respectively. Trophoblast migration and invasion were detected by wound-healing and transwell invasion assays. RNA pull-down and Co-IP assays were used to indicate the interaction between MALAT1 and FBXW7 or the interaction between FBXW7 and CRY2. The results showed significantly decreased MALAT1 expression in the villous specimens from the RSA patients relative to that in the villous specimens from the missed abortion patients and the normal villous specimens. MALAT1 promoted trophoblast cell migration and invasion by negatively regulating CRY2 protein expression. MALAT1 recruited FBXW7 to impair CRY2 protein stability. In conclusion, MALAT1 downregulation in trophoblasts might be related to miscarriage. MALAT1 may recruit the E3 ubiquitin ligase FBXW7 to induce CRY2 ubiquitin-mediated degradation and participate in trophoblast migration and invasion.

Depletion of lncRNA MALAT1 inhibited sunitinib resistance through regulating miR-362-3p-mediated G3BP1 in renal cell carcinoma

Long non-coding RNA metastasis associated with lung adenocarcinoma transcript 1 (MALAT1) contributes to chemotherapy resistance in some cancers, but the role of MALAT1 in sunitinib (SU) chemoresistance of carcinoma (RCC) is still unknown. In this study, MALAT1 expression in SU-resistance tumor tissues and cells was tested by qRT-PCR. Then, CCK-8, Annexin V-FITC/PI, transwell, and Western blotting assays were used to evaluate cell viability and IC50, apoptosis, cell invasion, and resistance of SU-resistance RCC cells after transfected with small interfering RNA against MALAT1. Further, RNA pull-down and luciferase reporter assay were applied to investigate the underlying mechanism of MALAT1 in SU resistance. The results showed that MALAT1 expression was dramatically upregulated in SU-resistance RCC tissues and cell lines. Knockdown of MALAT1 inhibited proliferation, invasion, and SU chemoresistance, but induced apoptosis in RCC cells. The results of RNA pull-down and luciferase reporter assay indicated that MALAT1 could interact with miR-362-3p and miR-362-3p interact with RasGAP SH3-domain-Binding Protein 1 (G3BP1). Moreover, G3BP1 also played a role in SU chemoresistance of RCC cells, and MALAT1 could perform as a miR-362-3p sponge to modulate G3BP1 expression. Rescue experiments suggested that downregulation of miR-362-3p and overexpression of G3BP1 can reverse the SU chemosensitivity of MALAT1 knockdown in RCC cells. In conclusion, depletion of LncRNA MALAT1 inhibited SU chemoresistance through modulating G3BP1 via sponging miR-362-3p in RCC cells, suggesting that targeting MALAT1 may be a potential therapeutic strategy for SU-resistance RCC.

Metastasis Associated Lung Adenocarcinoma Transcript 1: An update on expression pattern and functions in carcinogenesis

The Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is among long non-coding RNAs (lncRNAs) which has disapproved the old term of "junk DNA" which was used for majority of human genome which are not transcribed to proteins. An extensive portion of literature points to the fundamental role of this lncRNA in tumorigenesis process of diverse cancers ranging from solid tumors to leukemia. Being firstly identified in lung cancer, it has prognostic and diagnostic values in several cancer types. Consistent with the proposed oncogenic roles for this lncRNA, most of studies have shown up-regulation of MALAT1 in malignant tissues compared with non-malignant/normal tissues of the same source. However, few studies have shown down-regulation of MALAT1 in breast cancer, endometrial cancer, colorectal cancer and glioma. In the current study, we have conducted a comprehensive literature search and provided an up-date on the role of MALAT1 in cancer biology. Our investigation underscores a potential role as a diagnostic/prognostic marker and a putative therapeutic target for MALAT1.

Long noncoding RNAs in cancer: From discovery to therapeutic targets

Long noncoding RNAs (lncRNAs) have recently gained considerable attention as key players in biological regulation; however, the mechanisms by which lncRNAs govern various disease processes remain mysterious and are just beginning to be understood. The ease of next-generation sequencing technologies has led to an explosion of genomic information, especially for the lncRNA class of noncoding RNAs. LncRNAs exhibit the characteristics of mRNAs, such as polyadenylation, 5' methyl capping, RNA polymerase II-dependent transcription, and splicing. These transcripts comprise more than 200 nucleotides (nt) and are not translated into proteins. Directed interrogation of annotated lncRNAs from RNA-Seq datasets has revealed dramatic differences in their expression, largely driven by alterations in transcription, the cell cycle, and RNA metabolism. The fact that lncRNAs are expressed cell- and tissue-specifically makes them excellent biomarkers for ongoing biological events. Notably, lncRNAs are differentially expressed in several cancers and show a distinct association with clinical outcomes. Novel methods and strategies are being developed to study lncRNA function and will provide researchers with the tools and opportunities to develop lncRNA-based therapeutics for cancer.

LncRNA NONHSAT113026 represses renal cell carcinoma tumorigenesis through interacting with NF-κB/p50 and SLUG

Renal cell carcinoma (RCC) is one of the most lethal urological malignancies, yet its pathogenesis remains unclear. Here, we reported a long non-coding RNA (lncRNA), NONHSAT 113026 (NOAT113026), which may play an important role in the pathogenesis of RCC. The expression level of NOAT113026 was estimated by qPCR from 76 pairs of RCC and non-tumor (NT) samples. The correlation between NOAT113026 and clinical data of RCC patients was analyzed. NOAT113026 was overexpressed in 786-O and ACHN cell lines by lentivirus-mediated technology and the oncological behavioral changes of RCC cells were observed along with tumorigenicity in experimental nude mice. Compared to the adjacent tissues, NOAT113026 was noticeably downregulated in RCC. Survival analysis showed that the lower the expression level of NOAT113026 was, the shorter the disease-free survival and overall survival in RCC would be. Overexpression of NOAT113026 can decrease the ability of cell migration, invasion, proliferation, and colony formation by regulating NF-κB/p50 and SLUG through a mechanism that involves lncRNA-mRNA interactions. In conclusion, our data suggest that NOAT113026 could be a carcinostatic RNA in RCC, which may serve as a potential prognostic factor and a promising therapeutic target for malignant RCC.

Long non-coding RNA XIST regulates miR-106b-5p/P21 axis to suppress tumor progression in renal cell carcinoma

Long non-coding RNAs (lncRNAs) have been demonstrated to exert important roles in cancer development and progression. The biological function of lncRNA X-inactive specific transcript (XIST) in the development of renal cell carcinoma (RCC) and the underlying mechanisms are still largely unknown. In this study, we found that XIST was down-regulated in RCC tissues and cells. Overexpression of XIST significantly suppressed cell proliferation and induced cell G0/G1 arrest in vitro and inhibited tumor growth in vivo. We further found that XIST could directly interact with miR-106b-5p and increase the expression of P21. Thus, XIST positively regulated the expression of P21 through sponging miR-106b-5p, and played a tumor suppressor role in RCC. Moreover, we found that curcumin could regulate XIST/miR-106b-5p/P21 axis in RCC cells. Our study exhibits the role of XIST as a miRNA sponge in RCC and supports the potential application of XIST in RCC therapy.

High LINC01605 expression predicts poor prognosis and promotes tumor progression via up-regulation of MMP9 in bladder cancer

The advent of high-throughput sequencing methods has facilitated identification of novel long non-coding RNAs (lncRNAs), which have been demonstrated to play an important role in multiple tumors. Moreover, with the assistance of bioinformatics analysis, LINC01605 has been found to be up-regulated in bladder cancer (BC) tissues compared with normal tissues. Hence, the present study was to explore its specific biological role and related mechanism in BC. The relative expression level of LINC01605 was measured in a cohort of BC tissues with matched normal tissues as well as human BC cell lines by quantitative real-time PCR (qRT-PCR). Survival analysis was performed to explore the relationship between LINC01605 expression and the prognosis of BC patients. The biological function of LINC01605 was studied in vitroand in vivo, by means of CCK-8 assay, colony formation assay, transwell assay, and tumor xenografts mice model. LINC01605 was found to be frequently highly expressed in both human BC cells and tissues. Survival analysis indicated that high LINC01605 expression was associated with higher histological grade and clinical stages. In addition, down-regulated LINC01605 in BC cells could significantly inhibit the abilities of proliferation, migration, and invasion in vitro and knockdown of LINC01605 in subcutaneous xenograft tumor model could impede tumorigenesis in vivo. Mechanistically, LINC01605 could activate epithelial–mesenchymal transition (EMT) signaling pathway and promote the expression of matrix metallopeptidase (MMP) 9 (MMP9). In summary, our results shed light on that LINC01605, as a new prognostic biomarker, could promote the proliferation, migration, and invasion of BC cells via activating EMT signaling pathway and up-regulating MMP9 expression.

Hypoxia-regulated lncRNA CRPAT4 promotes cell migration via regulating AVL9 in clear cell renal cell carcinomas

Introduction

Long noncoding RNAs (lncRNAs) are proven to be key regulators in cancer biology. Our screening effort for clear cell renal cell carcinoma (ccRCC) prognosis-associated lncRNAs identified a novel lncRNA, ccRCC prognosis-associated transcript 4 (CRPAT4), as one of the top candidates that was previously uncharacterized. The aim of this study was to verify the clinical significance of CRPAT4 in ccRCC patients and to explore its biological role as well as the underlying mechanisms, in ccRCC cell lines.

Materials and methods

Quantitative real-time polymerase chain reaction (PCR) was performed to demonstrate that CRPAT4 was differentially expressed between ccRCC and the normal controls and that high CRPAT4 expression significantly associated with advanced Fuhrman nuclear grades.

Results

Kaplan–Meier survival analysis with The Cancer Genome Atlas KIRC RNA sequencing data indicated that high CRPAT4 expression was significantly associated with poor overall survival and progression-free survival. Functional studies indicated that CRPAT4 was an HIF-1α regulated gene, and CRPAT4 knockdown significantly inhibited cell migration and proliferation in the absence of HIF-1α. In addition, a mechanistic study revealed that CRPAT4 could regulate the expression of the migration-associated protein AVL9.

Conclusion

Collectively, our study first identified CRPAT4 as a hypoxia-regulated lncRNA, acting as an oncogene in ccRCC progression via regulating AVL9 protein, thus expanding our knowledge on the hypoxia pathway in ccRCC biology from a noncoding perspective. Moreover, CRPAT4 has the potential to be a prognostic marker in ccRCC patients.

Integrated analysis of differentially expressed profiles and construction of a competing endogenous long non-coding RNA network in renal cell carcinoma

Background

Long non-coding RNAs (lncRNAs) play crucial roles in the initiation and progression of renal cell carcinoma (RCC) by competing in binding to miRNAs, and related competitive endogenous RNA (ceRNA) networks have been constructed in several cancers. However, the coexpression network has been poorly explored in RCC.

Methods

We collected RCC RNA expression profile data and relevant clinical features from The Cancer Genome Atlas (TCGA). A cluster analysis was explored to show different lncRNA expression patterns. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses and gene set enrichment analysis (GSEA) were performed to analyze the functions of the intersecting mRNAs. Targetscan and miRanda bioinformatics algorithms were used to predict potential relationships among RNAs. Univariate Cox proportional hazards regression was conducted to determine the RNA expression levels and survival times.

Results

Bioinformatics analysis revealed that the expression profiles of hundreds of aberrantly expressed lncRNAs, miRNAs, and mRNAs were significantly changed between different stages of tumors and non-tumor groups. By combining the data predicted by databases with intersection RNAs, a ceRNA network consisting of 106 lncRNAs, 26 miRNAs and 69 mRNAs was established. Additionally, a protein interaction network revealed the main hub nodes (VEGFA, NTRK2, DLG2, E2F2, MYB and RUNX1). Furthermore, 63 lncRNAs, four miRNAs and 31 mRNAs were significantly associated with overall survival.

Conclusion

Our results identified cancer-specific lncRNAs and constructed a ceRNA network for RCC. A survival analysis related to the RNAs revealed candidate biomarkers for further study in RCC.

Long Noncoding RNA Small Nucleolar RNA Host Gene 1 (SNHG1) Promotes Renal Cell Carcinoma Progression and Metastasis by Negatively Regulating miR-137

Background

Data on the expression of RCC tissues from the GEO database and patient survival data from TCGA were used to explore the prognostic significance of long noncoding RNA SNHG1. SNHG1 has been reported to participate in the development of several cancers, but, the underlying mechanism of SNHG1 in renal cell carcinoma (RCC) has not been reported. The purpose of our study was to investigate the potential function of SNHG1 in RCC.

Material/Methods

The expression of SNHG1 in 40 cases of RCC and adjacent normal tissues and 5 cell lines was detected by qRT-PCR. Cell proliferation, Transwell assay, and Western blotting assay were carried out to investigate the biological function of SNHG1. A rescue experiment was performed to verify that miR-137 can partly impede the effect of SNHG1 on renal cancer cells.

Results

SNHG1 was identified to be overexpressed in RCC tissues and RCC cell lines. High levels of SNHG1 were correlated with poor prognosis of RCC patients. Knockdown of SNHG1 suppressed the proliferation, invasion, and EMT capacity in RCC. Moreover, miR-137 abrogated the effect of SNHG1 on RCC.

Conclusions

SNHG1 is significantly upregulated in RCC and renal cancer cell lines. Overexpression of SNHG1 participates in RCC tumorigenesis by regulating miR-137.

Platelet RNA signatures for the detection of cancer

Platelets are equipped with RNA processing machineries, such as pre-mRNA splicing, pre-miRNA processing, and mRNA translation. Since platelets are devoid of a nucleus, most RNA transcripts in platelets are derived from megakaryocytes during thrombocytogenesis. However, platelets can also ingest RNA molecules during circulation and/or interaction with other cell types. Since platelets were first described by Bizzozero in 1881, their well-established role in hemostasis and thrombosis has been intensively studied. However, in the past decades, the list of biological processes in which platelets play an important role keeps expanding. In this review, we discuss how platelet RNA biomarker signatures can be altered in the presence of cancer.

Long Noncoding RNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1) Promotes Renal Cell Carcinoma Progression via Sponging miRNA-429

Background

It is well known that long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is closely correlated with the tumorigenesis of multiple cancers, including renal cell carcinoma (RCC). However, the potential functional mechanism is still elusive.

Material/Methods

In our present research, quantitative real-time polymerase chain reaction (qRT-PCR) was performed for the measurement of MALAT1 and miR-429. CCK-8 assay and Transwell assay were performed for the proliferation, migration, and invasion abilities of RCC cells. Dual-luciferase reporter assay was performed to validate the interaction within MALAT1 and miR-429.

Results

Data found that MALAT1 was overexpressed in RCC clinical samples and cell lines. Moreover, loss-of-functional experiments showed that MALAT1 knockdown suppress the proliferation, migration, and invasion abilities of RCC cells. RT-PCR showed that miR-429 expression was downregulated in RCC cell lines, which was negatively correlated with that of MALAT1. Bioinformatics analysis suggested that miR-429 had complementary binding sequences with MALAT1, which was confirmed by dual-luciferase reporter assay.

Conclusions

In summary, our results concluded that MALAT1 functioned as an oncogene in RCC by sponging miR-429, acting as its competing endogenous RNA (ceRNA).

Long non-coding RNAs: An essential emerging field in kidney pathogenesis

Human Genome Project has made it clear that a majority of the genome is transcribed into the non-coding RNAs including microRNAs as well as long non-coding RNAs (lncRNAs) which both can affect different features of cells. LncRNAs are long heterogenous RNAs that regulate gene expression and a variety of signaling pathways involved in cellular homeostasis and development. Studies over the past decade have shown that lncRNAs have a major role in the kidney pathogenesis. The effective roles of lncRNAs have been recognized in renal ischemia, injury, inflammation, fibrosis, glomerular diseases, renal transplantation, and renal cell carcinoma. The present review outlines the role and function of lncRNAs in kidney pathogenesis as novel essential regulators. Molecular mechanism insights into the functions of lncRNAs in kidney pathophysiological processes may contribute to effective future therapeutics.

Ultraconserved element uc.372 drives hepatic lipid accumulation by suppressing miR-195/miR4668 maturation

Ultraconserved (uc) RNAs, a class of long non-coding RNAs (lncRNAs), are conserved across humans, mice, and rats, but the physiological significance and pathological role of ucRNAs is largely unknown. Here we show that uc.372 is upregulated in the livers of db/db mice, HFD-fed mice, and NAFLD patients. Gain-of-function and loss-of-function studies indicate that uc.372 drives hepatic lipid accumulation in mice by promoting lipogenesis. We further demonstrate that uc.372 binds to pri-miR-195/pri-miR-4668 and suppresses maturation of miR-195/miR-4668 to regulate expression of genes related to lipid synthesis and uptake, including ACC, FAS, SCD1, and CD36. Finally, we identify that uc.372 is located downstream of the insulinoma-associated 2 (INSM2) gene that is transcriptionally activated by upstream transcription factor 1 (USF1). Our findings reveal a novel mechanism by which uc.372 drives hepatic steatosis through inhibition of miR-195/miR-4668 maturation to relieve miR-195/miR-4668-mediated suppression of functional target gene expression.

Ultraconserved RNAs are a class of long non-coding RNAs whose functions are yet to be identified. Here Guo and colleagues show that an ultraconserved RNA uc.372 promotes lipogenesis and lipid accumulation within the hepatocytes by suppressing the maturation of miR-195/miR-4668 that inhibits lipogenic gene expression.

The long non-coding RNA MALAT1 activates Nrf2 signaling to protect human umbilical vein endothelial cells from hydrogen peroxide

The potential effect of the long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) against hydrogen peroxide (H₂O₂)-induced oxidative injury in endothelial cells was tested. We show that forced-expression of MALAT1 using a lentiviral vector ("LV-MALAT1") significantly attenuated H₂O₂-induced death and apoptosis of human umbilical vein endothelial cells (HUVECs). Conversely, knocking down of MALAT1 by targeted siRNA exacerbated H₂O₂-induced HUVEC injury. For the mechanism study, we show that LV-MALAT1 induced Keap1 downregulation, leading to nuclear-factor-E2-related factor 2 (Nrf2) stabilization and activation. Critically, Nrf2 shRNA almost completely abolished LV-MALAT1-mediated HUVEC protection against H₂O₂. Significantly, H₂O₂-induced oxidative stress, lipid peroxidation and DNA damages in HUVECs were attenuated by LV-MALAT1, but were intensified with MALAT1 siRNA. In summary, we identified a novel signaling axis involving MALAT1, Keap1 and Nrf2, which in turn protects HUVECs from oxidative injury.

Downregulation of lncRNA SDPR-AS is associated with poor prognosis in renal cell carcinoma

Renal cell carcinoma (RCC) is a common type of kidney cancer. Normally, surgical treatment can prolong life, but only for patients with early stage tumors. However, it is difficult for early detection strategies to distinguish between benign and malignant kidney tumors. Therefore, potential biomarkers for early diagnosis and prognosis of RCC are needed. Intriguingly, mounting evidence has demonstrated that many long noncoding RNAs (lncRNAs) are strongly linked to cancers. Indeed, promising RCC-associated lncRNA biomarkers have also been identified. However, the functional and prognostic roles of the antisense (AS) serum deprivation response (SDPR) lncRNA (SDPR-AS) in RCC remain largely unknown. The aims of this study were to investigate the expression and prognostic relevance of SDPR-AS in RCC. We uncovered the downregulated expressions of both lncRNA SDPR-AS and its protein-coding gene, SDPR, in RCC tissues compared to the matched normal tissues. Furthermore, SDPR-AS and SDPR expressions were positively correlated. Overexpression and knockdown experiments suggested that SDPR-AS and SDPR were coregulated in RCC cell lines. In addition, overexpression of SDPR-AS suppressed cell migration and invasion, but not cell growth. Furthermore, expression of SDPR-AS was associated with tumor differentiation and lymphatic metastasis. Kaplan–Meier survival and log-rank tests demonstrated the association of elevated expression of SDPR-AS with increased overall survival. In conclusion, our results suggest that the SDPR-AS may serve as a prognostic biomarker and therapeutic target of RCC.

LncRNA CCAT1 inhibits cell apoptosis of renal cell carcinoma through up-regulation of Livin protein

This study was to investigate the involvement of long non-coding RNA (lncRNA) colon cancer-associated transcript-1 (CCAT1) in renal cell carcinoma (RCC) and to further uncover its underlying mechanism. In this study, the expression of CCAT1 and Livin of RCC tissues or cells was determined using qRT-PCR (quantitative real-time PCR) and western blot, respectively. RNA pulldown and RIP (RNA-Binding Protein Immunoprecipitation) assays were performed to examine the sequence interaction between CCAT1 and Livin. The viability and apoptosis of RCC cells was assessed by MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and TUNEL (TdT-mediated dUTP nick end labeling) assays, respectively. Mice of tumor animal models were established to observe the effect of CCAT1 on RCC tumor growth. The relative expression of CCAT1 in RCC tissues and cell lines was obviously higher than that of the control. CCAT1 knockdown could reduce cell viability and increase the apoptosis of RCC cells in vitro. Furthermore, Livin was significantly inhibited by CCAT1 silencing; RNA pulldown and RIP assays showed that CCAT1 was physically associated with Livin protein. Moreover, Livin overexpression not only significantly inhibited RCC cell apoptosis and increased cell viability, but completely reversed the si-CCAT1-mediated repression of cell viability. More importantly, CCAT1 silencing could inhibit the growth of RCC in vivo that was accompanied by the reduction of Livin in RCC tissues. CCAT1 inhibits RCC cell apoptosis and increases cell viability through up-regulation of Livin.