Long non-coding RNA LINC00858 exerts a tumor-promoting role in colon cancer via HNF4α and WNK2 regulation

LINC00858 facilitates formation of hepatic metastases from colorectal cancer via regulating the miR-132-3p/IGF2BP1 axis

Hepatic metastasis is a major cause of colorectal cancer (CRC)-related deaths. Presently, the role of long non-coding RNAs (lncRNAs) in hepatic metastases from CRC is elusive. We dissected possible interplay between LINC00858/miR-132-3p/IGF2BP1 via bioinformatics approaches. Subsequently we analyzed mRNA expression of LINC00858, miR-132-3p and IGF2BP1 through qRT-PCR. Western blot was used to detect protein expression of IGF2BP1. RNA immunoprecipitation chip and dual-luciferase assay validated interaction between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Cell viability, invasion, and migration were examined via CCK-8, colony formation, transwell and wound healing assays. Effect of LINC00858 on CRC hepatic metastases was validated via in vivo assay. Upregulated LINC00858 and IGF2BP1, and downregulated miR-132-3p were predicted in tumor tissues of patients with hepatic metastases from CRC. There were targeting relationships between LINC00858 and miR-132-3p, as well as miR-132-3p and IGF2BP1. Besides, LINC00858 facilitated progression of CRC cells. Rescue assay suggested that silencing LINC00858 suppressed CRC cell progression, while further silencing miR-132-3p or overexpressing IGF2BP1 reversed such effects. LINC00858 could facilitate CRC tumor growth and hepatic metastases. LINC00858 induced CRC hepatic metastases via regulating miR-132-3p/ IGF2BP1, and this study may deliver a new diagnostic marker for the disease.

Nanotherapeutic approaches for delivery of long non-coding RNAs: an updated review with emphasis on cancer

The long noncoding RNAs (lncRNAs) comprise a wide range of RNA species whose length exceeds 200 nucleotides, which regulate the expression of genes and cellular functions in a wide range of organisms. Several diseases, including malignancy, have been associated with lncRNA dysregulation. Due to their functions in cancer development and progression, lncRNAs have emerged as promising biomarkers and therapeutic targets in cancer diagnosis and treatment. Several studies have investigated the anti-cancer properties of lncRNAs; however, only a few lncRNAs have been found to exhibit tumor suppressor properties. Furthermore, their length and poor stability make them difficult to synthesize. Thus, to overcome the instability of lncRNAs, poor specificity, and their off-target effects, researchers have constructed nanocarriers that encapsulate lncRNAs. Recently, translational medicine research has focused on delivering lncRNAs into tumor cells, including cancer cells, through nano-drug delivery systems in vivo. The developed nanocarriers can protect, target, and release lncRNAs under controlled conditions without appreciable adverse effects. To deliver lncRNAs to cancer cells, various nanocarriers, such as exosomes, microbubbles, polymer nanoparticles, 1,2-dioleyl-3-trimethylammoniumpropane chloride nanocarriers, and virus-like particles, have been successfully developed. Despite this, every nanocarrier has its own advantages and disadvantages when it comes to delivering nucleic acids effectively and safely. This article examines the current status of nanocarriers for lncRNA delivery in cancer therapy, focusing on their potential to enhance cancer treatment.

Delineating the role of nuclear receptors in colorectal cancer, a focused review

Colorectal cancer (CRC) stands as one of the most prevalent form of cancer globally, causing a significant number of deaths, surpassing 0.9 million in the year 2020. According to GLOBOCAN 2020, CRC ranks third in incidence and second in mortality in both males and females. Despite extensive studies over the years, there is still a need to establish novel therapeutic targets to enhance the patients' survival rate in CRC. Nuclear receptors (NRs) are ligand-activated transcription factors (TFs) that regulate numerous essential biological processes such as differentiation, development, physiology, reproduction, and cellular metabolism. Dysregulation and anomalous expression of different NRs has led to multiple alterations, such as impaired signaling cascades, mutations, and epigenetic changes, leading to various diseases, including cancer. It has been observed that differential expression of various NRs might lead to the initiation and progression of CRC, and are correlated with poor survival outcomes in CRC patients. Despite numerous studies on the mechanism and role of NRs in this cancer, it remains of significant scientific interest primarily due to the diverse functions that various NRs exhibit in regulating key hallmarks of this cancer. Thus, modulating the expression of NRs with their agonists and antagonists, based on their expression levels, holds an immense prospect in the diagnosis, prognosis, and therapeutical modalities of CRC. In this review, we primarily focus on the role and mechanism of NRs in the pathogenesis of CRC and emphasized the significance of targeting these NRs using a variety of agents, which may represent a novel and effective strategy for the prevention and treatment of this cancer.

Current advancements and future perspectives of long noncoding RNAs in lipid metabolism and signaling

BACKGROUND

The investigation of lncRNAs has provided a novel perspective for elucidating mechanisms underlying diverse physiological and pathological processes. Compelling evidence has revealed an intrinsic link between lncRNAs and lipid metabolism, demonstrating that lncRNAs-induced disruption of lipid metabolism and signaling contribute to the development of multiple cancers and some other diseases, including obesity, fatty liver disease, and cardiovascular disease.

AIMOF REVIEW

The current review summarizes the recent advances in basic research about lipid metabolism and lipid signaling-related lncRNAs. Meanwhile, the potential and challenges of targeting lncRNA for the therapy of cancers and other lipid metabolism-related diseases are also discussed.

KEY SCIENTIFIC CONCEPT OF REVIEW

Compared with the substantial number of lncRNA loci, we still know little about the role of lncRNAs in metabolism. A more comprehensive understanding of the function and mechanism of lncRNAs may provide a new standpoint for the study of lipid metabolism and signaling. Developing lncRNA-based therapeutic approaches is an effective strategy for lipid metabolism-related diseases.

Cancer-associated fibroblast-released extracellular vesicles carrying miR-199a-5p induces the progression of​ gastric cancer through regulation of FKBP5-mediated AKT1/mTORC1 signaling pathway

Accumulating evidence has unfolded the significance of extracellular vesicles (EVs) in diseases and cancers. Here, we attempted to discuss the role of cancer-associated fibroblasts (CAFs)-derived EVs containing miR-199a-5p in gastric tumorigenesis. Upregulated miR-199a-5p was first identified in cancer cells. Then, we selected CAFs for isolation of EVs which were co-cultured with AGS cells. We observed successful delivery of miR-199a-5p via CAF-derived EVs. Besides, miR-199a-5p promoted malignant properties of AGS cells. Moreover, miR-199a-5p downregulated FKBP5, leading to upregulated phosphorylation level of AKT1, which promoted the malignant phenotypes of AGS cells by activating mammalian target of rapamycin complex 1(mTORC1). Exosomal miR-199a-5p from CAFs promoted gastric tumorigenesis in vivo. Our findings point toward the critical role of CAFs-derived EVs carrying miR-199a-5p in gastric cancer progression.

An update regarding the role of WNK kinases in cancer

Mammalian WNK kinases (WNKs) are serine/threonine kinases that contain four members, WNK1-4. They function to maintain ion homeostasis and regulate blood pressure in mammals. Recent studies have revealed that the dysregulation of WNKs contributes to tumor growth, metastasis, and angiogenesis through complex mechanisms, especially through phosphorylating kinase substrates SPS1-related proline/alanine-rich kinase (SPAK) and oxidative stress-responsive kinase 1 (OSR1). Here, we review and discuss the relationships between WNKs and several key factors/biological processes in cancer, including ion channels, cation chloride cotransporters, sodium bicarbonate cotransporters, signaling pathways, angiogenesis, autophagy, and non-coding RNAs. In addition, the potential drugs for targeting WNK-SPAK/OSR1 signaling have also been discussed. This review summarizes and discusses knowledge of the roles of WNKs in cancer, which provides a comprehensive reference for future studies.

microRNA-324-3p suppresses the aggressive ovarian cancer by targeting WNK2/RAS pathway

Ovarian cancer (OC) has the highest mortality rate among gynecological cancers, which progresses owing to dysregulated microRNAs (miRNAs) expression. Our study attempts to reveal the mechanism by which decreased miR-324-3p expression suppresses OC proliferation. Quantitative real-time PCR, western blotting, in situ hybridization, and immunohistochemistry were performed to estimate miR-324-3p and WNK2 expression levels in OC cells and tissues. Cell Counting Kit-8, colony formation, EdU, and transwell assays were performed to analyze the influence of miR-324-3p and WNK2 on the proliferation and invasion ability of OC cells. Subsequently, xenograft models were established to examine the effects of WNK2 on OC cell proliferation in vivo, and databases and luciferase reporter assays were used to test the relationship between miR-324-3p and WNK2 expression. Then, we showed that miR-324-3p expression is decreased in OC cells and tissues, indicating its inhibitory effect on OC cell proliferation. Quantitative real-time PCR and luciferase reporter assays demonstrated that miR-324-3p inhibited WNK2 expression by directly binding to its 3’ untranslated region. WNK2, an upregulated kinase, promotes the proliferation and invasion of OC cells by activating the RAS pathway. Moreover, WNK2 can partly reverse the inhibitory effects of miR-324-3p on OC cell proliferation. Hence, we demonstrate that miR-324-3p suppressed ovarian cancer progression by targeting the WNK2/RAS pathway. Our study provides theoretical evidence for the clinical application potential of miR-324-3p.

LINC00858 promotes colon cancer progression through activation of STAT3/5 signaling by recruiting transcription factor RAD21 to upregulate PCNP

The purpose of our investigation is to explore the putative molecular mechanisms underpinning LINC00858 involvement in colon cancer. The expression of LINC00858 in TCGA data was identified using the GEPIA website. Colon cancer cancerous tissues were clinically collected. The expression of LINC00858, RAD21, and PCNP in colon tissues or cells was determined using RT-qPCR. The interactions among LINC00858, RAD21, and PCNP promoter region were determined by means of RNA pull down, RIP, and ChIP assays. Cell proliferative, apoptotic, invasive, and migrated capabilities were evaluated. Western blot was conducted to determine RAD21, PCNP, phosphorylated (p)-STAT3, STAT3, p-STAT5 and STAT5 and apoptosis related proteins. A nude mouse model of colon cancer was constructed and tumorigenesis of colon cancer cells was observed. LINC00858 was upregulated in cancerous tissues and cells. LINC00858 recruited the transcription factor RAD21. Overexpression of LINC00858 promoted the binding of RAD21 and PCNP promoter region, which increased the expression of PCNP. Silencing of RAD21 or PCNP reversed the promoting effect of LINC00858 on the disease initiation and development. PCNP silencing inhibited proliferative ability and promoted apoptotic ability of cancerous cells via STAT3/5 inhibition, which was reversed by colivelin-activated STAT3. In vivo experiments further verified that LINC00858 enhanced the tumorigenicity of colon cancer cells in vivo by regulating the RAD21/PCNP/STAT3/5 axis. It indicated the promoting role of LINC00858 in colon cancer progression though activating PCNP-mediated STAT3/5 pathway by recruiting RAD21.

LncRNA KCNQ1OT1 promotes apoptosis and oxidative stress of human lens epithelial cells through epigenetic regulation of WRN

PURPOSE

Long non-coding RNA KCNQ1OT1 is fundamental to age-related cataract (ARC), whereas the underlying mechanism is still unknown. Here, we explored the possible mechanism of KCNQ1OT1 in ARC.

METHODS

The expression of KCNQ1OT1 in ARC patients and H₂O₂-treated human lens epithelial cell line SRA01/04 was detected. Gene and protein expression were examined by quantitative real-time PCR and western blot. Cell viability and apoptosis were detected by CCK-8 assay and flow cytometry. The content of reactive oxygen species (ROS) was assessed by fluorescent probe DCFH-DA. The relationship among KCNQ1OT1, G9a, H3K9me1/2 and WRN was verified by RNA pull down and Chromatin immunoprecipitation.

RESULTS

KCNQ1OT1 was up-regulated in the anterior lens capsule tissues of ARC patients and H₂O₂-treated SRA01/04 cells. KCNQ1OT1 overexpression suppressed cell viability and facilitated apoptosis in H₂O₂-treated SRA01/04 cells. KCNQ1OT1 up-regulation enhanced the levels of ROS and malondialdehyde (MDA), and reduced the levels of superoxide dismutase (SOD) and catalase (CAT) in H₂O₂-treated SRA01/04 cells. WRN up-regulation led to a result opposite to KCNQ1OT1 overexpression. The influence of WRN up-regulation on cell viability, apoptosis and oxidative stress of SRA01/04 cells was rescued by KCNQ1OT1 overexpression. Additionally, KCNQ1OT1 interacted with G9a. Both G9a and H3K9me1/2 interacted with WRN promoter. G9a deficiency significantly enhanced WRN expression and repressed H3K9me1/2 expression in SRA01/04 cells, which was abrogated by KCNQ1OT1 up-regulation.

CONCLUSION

This study demonstrated that KCNQ1OT1 promoted apoptosis and oxidative stress of human LECs through G9a-driven epigenetic regulation of WRN. This work highlights a novel lncRNA involving key regulators of ARC.

Risk Scores Based on Six Survival-Related RNAs in a Competing Endogenous Network Composed of Differentially Expressed RNAs Between Clear Cell Renal Cell Carcinoma Patients Carrying Wild-Type or Mutant Von Hippel-Lindau Serve Well to Predict Malignancy and Prognosis

Clear cell renal cell carcinoma (ccRCC) carrying wild-type Von Hippel–Lindau (VHL) tumor suppressor are more invasive and of high morbidity. Concurrently, competing endogenous RNA (ceRNA) network has been suggested to play an important role in ccRCC malignancy. In order to understand why the patients carrying wild-type VHL gene have high degrees of invasion and morbidity, we applied bioinformatics approaches to identify 861 differentially expressed RNAs (DE-RNAs) between patients carrying wild-type and patients carrying mutant VHL from The Cancer Genome Atlas (TCGA) database, established a ceRNA network including 122 RNAs, and elected six survival-related DE-RNAs including Linc00942, Linc00858, RP13_392I16.1, hsa-miR-182-5p, hsa-miR-183-5p, and PAX3. Examining clinical samples from our hospital revealed that patients carrying wild-type VHL had significantly higher levels of all six RNAs than those carrying mutant VHL. Patients carrying wild-type VHL had significantly higher risk scores, which were calculated based on expression levels of all six RNAs, than those carrying mutant VHL. Patients with higher risk scores had significantly shorter survival times than those with lower risk scores. Therefore, the risk scores serve well to predict malignancy and prognosis.

Disruption of Tumor Suppressors HNF4α/HNF1α Causes Tumorigenesis in Liver

The hepatocyte nuclear factor-4α (HNF4α) and hepatocyte nuclear factor-1α (HNF1α) are transcription factors that influence the development and maintenance of homeostasis in a variety of tissues, including the liver. As such, disruptions in their transcriptional networks can herald a number of pathologies, such as tumorigenesis. Largely considered tumor suppressants in liver cancer, these transcription factors regulate key events of inflammation, epithelial-mesenchymal transition, metabolic reprogramming, and the differentiation status of the cell. High-throughput analysis of cancer cell genomes has identified a number of hotspot mutations in HNF1α and HNF4α in liver cancer. Such results also showcase HNF1α and HNF4α as important therapeutic targets helping us step into the era of personalized medicine. In this review, we update current findings on the roles of HNF1α and HNF4α in liver cancer development and progression. It covers the molecular mechanisms of HNF1α and HNF4α dysregulation and also highlights the potential of HNF4α as a therapeutic target in liver cancer.

The tumorigenic function of LINC00858 in cancer

Long non-coding RNA (lncRNA) plays an important regulatory role in the occurrence and development of human cancer. LINC00858 is a newly discovered lncRNA with a length of 2685 nucleotides. Existing studies have shown that LINC00858 has abnormally high expression levels in malignant tumors such as colorectal cancer, gastric cancer, hepatocellular carcinoma, lung cancer, non-small cell lung cancer, ovarian cancer, osteosarcoma, retinoblastoma, Wilms tumor, bladder cancer, and cervical cancer. By regulating a variety of microRNAs, LINC00858 can affect tumor cell proliferation, invasion, metastasis, and apoptosis. Related research also found that LINC00858 is related to nuclear transcription factor/protein kinase and gene methylation. The aberrant expression of LINC00858 is related to the prognosis and clinicopathological characteristics of a variety of tumors. Overexpressed LINC00858 is closely related to the clinical stage, lymph node metastasis, and distant metastasis of cancer, including colorectal cancer, gastric cancer, non-small cell lung cancer, ovarian cancer, and Wilms tumor. Also, it is summarized that LINC00858 can regulate MAPK and TGF-β signaling pathways. This review shows that LINC00858 as an important oncogene can promote tumorigenesis and cancer development.

Long non-coding RNAs and circular RNAs in tumor angiogenesis: From mechanisms to clinical significance

Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) execute a wide array of functions in physiological and pathological processes, including tumor progression. Angiogenesis, an elaborate multistep process driving new blood vessel formation, accelerates cancer progression by supplying nutrients and energy. Dysregulated lncRNAs and circRNAs can reportedly impact cancer progression by influencing angiogenesis. However, the expanding landscape of lncRNAs and circRNAs in tumor progression-dependent angiogenesis remains largely unknown. This review summarizes the major functions of angiogenic lncRNAs (Angio-LncRs) and angiogenic circRNAs (termed Angio-CircRs) and their cancer mechanisms. Moreover, we highlight the commonalities of lncRNAs and circRNAs in epigenetic, transcriptional, and post-transcriptional regulation as well as illustrate how Angio-LncRs and Angio-CircRs induce cancer onset and progression. We also discuss their potential clinical applications in diagnosis, prognosis, and anti-angiogenic therapies.

Lemur tyrosine kinase-3 (LMTK3) induces chemoresistance to cetuximab in colorectal cancer via the ERK/MAPK pathway

As an oncogenic kinase in multiple cancers, LMTK3 was deeply implicated in cancer pathogenesis. Nevertheless, its biological function in colorectal cancer (CRC) is still unclear. In this study, LMTK3 mRNA expression was assessed by RT-qPCR. LMTK3, phospho-ERK1/2 (p-ERK1/2), ERK1/2, and cleaved caspase-3 protein levels were detected by western blotting. Cetuximab (CTX)-resistant CRC cell models were constructed to investigate the mechanism of LMTK3-regulated CTX resistance in CRC. CTX half-maximal inhibitory concentration (IC₅₀), viability, apoptosis, cell cycle, migration, and invasion of CRC cells were analyzed via Cell Counting Kit-8 (CCK-8), flow cytometry, wound healing, and transwell assays. We found LMTK3 was distinctly upregulated in CRC tissues and cells, particularly in CTX-resistant CRC tissues and cells. LMTK3 inhibition lowered CTX half-maximal inhibitory concentration (IC₅₀) value, inhibited cell viability, induced cell apoptosis, triggered cell-cycle arrest, and impaired cell metastatic capability in CTX-resistant CRC cells. Moreover, we also demonstrated that LMTK3 induced CTX resistance in CRC via the activation of ERK/MAPK signaling in vitro. These results suggested a novel molecular mechanism by which LMTK3 participates in the development of CTX resistance in CRC.

Keep your eyes peeled for long noncoding RNAs: Explaining their boundless role in cancer metastasis, drug resistance, and clinical application

Cancer metastasis and drug resistance are two major obstacles in the treatment of cancer and therefore, the leading cause of cancer-associated mortalities worldwide. Hence, an in-depth understanding of these processes and identification of the underlying key players could help design a better therapeutic regimen to treat cancer. Earlier thought to be merely transcriptional junk and having passive or secondary function, recent advances in the genomic research have unravelled that long noncoding RNAs (lncRNAs) play pivotal roles in diverse physiological as well as pathological processes including cancer metastasis and drug resistance. LncRNAs can regulate various steps of the complex metastatic cascade such as epithelial-mesenchymal transition (EMT), invasion, migration and metastatic colonization, and also affect the sensitivity of cancer cells to various chemotherapeutic drugs. A substantial body of literature for more than a decade of research evince that lncRNAs can regulate gene expression at different levels such as epigenetic, transcriptional, posttranscriptional, translational and posttranslational levels, depending on their subcellular localization and through their ability to interact with DNA, RNA and proteins. In this review, we mainly focus on how lncRNAs affect cancer metastasis by modulating expression of key metastasis-associated genes at various levels of gene regulation. We also discuss how lncRNAs confer cancer cells either sensitivity or resistance to various chemo-therapeutic drugs via different mechanisms. Finally, we highlight the immense potential of lncRNAs as prognostic and diagnostic biomarkers as well as therapeutic targets in cancer.

Long non-coding RNA NEAT1 absorbs let-7 g-5p to induce epithelial-mesenchymal transition of colon cancer cells through upregulating BACH1

OBJECTIVE

Long noncoding RNAs (lncRNAs) are critical regulators in diverse human cancers. However, the role of lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) in colon cancer remains to be further investigated. We aimed to verify the role of NEAT1/let-7 g-5p/BTB and CNC homology 1 (BACH1) axis in colon cancer development.

METHODS

Expression of NEAT1, let-7 g-5p and BACH1 in colon cancer tissues and cells was determined. The interactions between NEAT1 and let-7 g-5p, and between let-7 g-5p and BACH1 were assessed. The colon cancer cell lines were treated with plasmids or oligonucleotides to alter NEAT1, BACH1 and let-7 g-5p expression. Then, viability, migration, invasion, and apoptosis of colon cells were evaluated, and the cell growth in vivo was observed as well.

RESULTS

NEAT1 and BACH1 were upregulated while let-7 g-5p was downregulated in colon cancer tissues and cells. NEAT1/BACH1 silencing or let-7 g-5p elevation suppressed colon cancer cell growth in vivo and in vitro. The effects of silenced NEAT1 on colon cancer cells and xenografts were reversed by downregulating let-7 g-5p. Down-regulation of BACH1 reversed the effect of NEAT1 overexpression on colon cancer cells. NEAT1 directly bound to let-7 g-5p and let-7 g-5p targeted BACH1.

CONCLUSION

Downregulated NEAT1 elevated let-7 g-5p to suppress EMT of colon cancer cells through inhibiting BACH1. This research may contribute to treatment of colon cancer.

Serine/Arginine Repetitive Matrix 2 Antisense RNA 1 Negatively Regulates miR-370-3p and Promotes Hyperplasia, Migration, and Aggression of the Colon Cancer Cell Line

The purpose of this study is to explore the effect and possible machine-processing of the long non-coding RNA (lncRNA) SRRM2-AS1 in the development and pathogenesis of colorectal cancer. LncRNA plays an important role in tumorigenesis and development. LncRNA can regulate gene transcription and translation, cell proliferation, differentiation and apoptosis by affecting gene expression pathways of various coding proteins. SRRM2-AS1 is a kind of lncRNA. Studies have confirmed that the expression of SRRM2-AS1 is increased in colon adenocarcinoma tissues of colon cancer patients and is closely related to the prognosis of patients. However, the influence and molecular mechanism of SRRM2-AS1 on the malignant biological behavior of colon cancer cells are no yet clear. SRRM2-AS1 may interact with miR-370-3p. Studies have confirmed that overexpression of miR-370-3p can inhibit the proliferation and epithelial-mesenchymal transition of colon cancer cells in vitro. However, it is not yet clear whether SRRM2-AS1 can target miR-370-3p to affect the occurrence and development of tumors. In this study, RT-qPCR was employed to detect levels of SRRM2-AS1 and miRNA-370-3p in carcinoma tissues and corresponding paracarcinoma tissues from 41 patients with colon cancer. SW1116 colon cancer cells were cultured in vitro and separated into 4 groups: (1) si-NC group, (2) si-SRRM2-AS1 group, (3) si-SRRM2-AS1+anti-miRNA-NC group, and (4) si-SRRM2-AS1+anti-miRNA-370-3p group. The CCK-8 assay and colony formation experiment was employed to gauge cell proliferation. The scratch test was used to detect cell migration while the transwell assay was used to detect cell invasion. Finally, Western blot analysis was employed to detect levels of Ki67, E-cadherin, and N-cadherin proteins in colorectal cancer cells. The dual-luciferase reporter gene experiment verified that SRRM2-AS1 regulates miRNA-370-3p. The study found that compared to paracarcinoma tissue, levels of SRRM2-AS1 in colon cancer tissues was increased (P < 0.05). Compared to the si-NC group, the SW1116 cell OD value, number of colonies formed, scratch healing rate, number of invasive cells, and expression levels of Ki67 and N-cadherin protein in the si-SRRM2-AS1 group were all decreased (P < 0.05). However, E-cadherin protein levels were elevated (P < 0.05). SRRM2-AS1 negatively regulates levels of miRNA-370-3p in SW1116 cells. Compared to the si-SRRM2-AS1+anti-miRNA-NC group, SW1116 cell OD value, number of colonies formed, scratch healing rate, number of invasive cells, and Ki67 and N-cadherin protein levels were increased (P < 0.05) in the si-SRRM2-AS1+anti-miRNA-370-3p group. Conversely, E-cadherin protein levels were decreased (P < 0.05). These findings indicate that SRRM2-AS1 is predominately expressed in cancerous colon tissues. Attenuating expression of SRRM2-AS1 may curb the hyperplasia of colon carcinoma cell line SW1116 and promote cell apoptosis by regulating miRNA-370-3p expression.

HLA complex group 11 is involved in colorectal carcinoma cisplatin resistance via the miR-214-5p/SOX4 axis

The aim of the present study was to investigate the roles and potential mechanisms of long non-coding RNA HLA complex group 11 (HCG11) in colorectal carcinoma. Reverse transcription-quantitative PCR was used to detect HCG11 expression in clinical tissues and survival analysis was performed to identify its prognostic value. In order to investigate its specific biological functions in colorectal carcinoma, the transfection technique was used for the knockdown and overexpression of HCG11. Dual-luciferase reporter gene and RNA pull-down assays were used to identify the binding association between HCG11 and microRNA (miR)-214-5p. Western blot analysis was used to detect the mechanism of epithelial-mesenchymal transition (EMT) regulation in tumor cells in the pathway downstream of HCG11. HCG11 level was high in colorectal carcinoma tissues, which was associated with poor patient prognosis; however, chemotherapy may prevent the upregulation of HCG11 in colorectal carcinoma. HCG11-knockdown suppressed the proliferation, migration and chemotherapeutic sensitivity of colorectal carcinoma cells, whereas HCG11-overexpression enhanced chemotherapeutic sensitivity. miR-214-5p was revealed to be a target gene, and upon direct interaction, a negative regulator of HCG11 in colorectal carcinoma cells. Inhibition of miR-214-5p reversed the restriction of HCG11 on the malignant activity of colorectal carcinoma cells, while miR-214-5p mediated the chemotherapy-related intracellular EMT pathway. In conclusion, HCG11 is a vital oncogene of colorectal carcinoma involved in mediating the chemotherapeutic resistance of tumors.

LINC00511-dependent inhibition of IL-24 contributes to the oncogenic role of HNF4α in colorectal cancer

Hepatocyte nuclear factor 4 α (HNF4α) is an important transcription factor that acts as a pro-proliferative mediator during tumorigenesis, yet its function in colorectal cancer (CRC) remain unclear. Hence, this study aims to explore roles that HNF4α plays in the CRC development. RNA quantification analysis was conducted to characterize the expression pattern of long intergenic noncoding RNA 00511 (LINC00511)/HNF4α/IL-24 in CRC tissues and cell lines. Using gain- and loss-of-function approaches, effects of HNF4α/LINC00511/IL-24 axis on biological processes such as proliferative, migrating, invading, apoptotic, and tumorigenic functions of CRC cells were evaluated. We further identified the interactions among HNF4α/LINC00511/EZH2/IL-24 using RNA binding protein immunoprecipitation, RNA pull-down along with chromatin immunoprecipitation (ChIP). LINC00511 was an upregulated lncRNA in CRC tissues and cells, which played an oncogenic role by strengthening the malignant phenotypes of CRC cells. LINC00511 downregulated IL-24 expression by interacting with EZH2. HNF4α could enhance LINC00511 transcription in an epigenetic manner, which finally accelerated cancer progression and tumorigenesis through LINC00511-mediated inhibition of IL-24. Those data together demonstrated the contribution of HNF4α to the progression of CRC through mediating the LINC00511/EZH2/IL-24 axis. Hence, our study provides a promising therapeutic target for CRC.NEW & NOTEWORTHY Our findings on the roles of hepatocyte nuclear factor 4 α/long intergenic noncoding RNA 00511/IL-24 axis provide new insights into the CRC and offer potential targets for translational applications.

Carbonyl Reductase 3-Antisense RNA 1 Negatively Regulates microRNA-337-3p Expression: Effects on Proliferation, Migration, and Invasion of Lung Cancer Cells

Lung cancer, a malignant tumor, is associated with high morbidity and mortality worldwide. We studied the influence and mechanism of CBR3-AS1 on lung cancer cell proliferation, migration, and infiltration. The expression of CBR3-AS1 and miRNA-337-3p were higher and lower (P < 0.05), respectively, in lung cancer tissues than in paracancerous tissues. After inhibiting the expression of CBR3-AS1, the OD value of A549 cells, cloning formation numbers, migrating and invasive numbers, N-cadherin protein expression levels were lower. The G0-G1 cell cycle periods was longer. The S cell cycle periods was shorter. The E-cadherin protein expression levels higher (P < 0.05 in all cases). CBR3-AS1 negatively regulated miRNA-337-3p expression in A549 cells (P < 0.05). After inhibiting the expression of CBR3-AS1 and miRNA-337-3p, the OD value of A549 cells was lower, cloning formation numbers, migrating and invasive numbers, N-cadherin protein expression levels were lower. The G0-G1 cell cycle periods was longer. The S cell cycle periods was shorter. The E-cadherin protein expression levels was higher (P < 0.05 in all cases). CBR3-AS1 expression was increased in lung cancer tissues, and interference with CBR3-AS1 expression could inhibit the proliferation, migration, and infiltration of lung cancer A549 cells by negatively regulating miRNA-337-3p.

Identifying critical protein-coding genes and long non-coding RNAs in non-functioning pituitary adenoma recurrence

Non-functioning pituitary adenoma (NFPA) is a very common type of intracranial tumor. Monitoring and predicting the postoperative recurrence of NFPAs is difficult, as these adenomas do not present with serum hormone hypersecretion. Long non-coding RNAs (lncRNAs) and protein-coding genes (PCGs) play critical roles in the development and progression of numerous tumors. However, the complex network of RNA interactions related to the mechanisms underlying the postoperative recurrence of NFPA is still unclear. In the present study, 73 patients with NFPA were investigated using high-throughput sequencing and follow-up investigations. In total, 6 of these patients with recurrence within 1 year after surgery were selected as the fast recurrence group, and 6 patients with recurrence 5 years after surgery were selected as the slow recurrence group. By performing differential expression analysis of the fast recurrence and slow recurrence groups, a set of differentially expressed PCGs and lncRNAs were obtained (t-test, P<0.05). Next, protein-protein interaction coregulatory networks and lncRNA-mRNA coexpression networks were identified. In addition, the hub lncRNA-mRNA modules related to NFPA recurrence were further screened and transcriptome expression markers for NFPA regression were identified (log-rank test, P<0.05). Finally, the ability of the hub and module genes to predict recurrence and progression-free survival in patients with NFPA was evaluated. To confirm the credibility of the bioinformatic analyses, nucleolar protein 6 and LL21NC02-21A1.1 were randomly selected from among the genes with prognostic significance for validation by reverse transcription-quantitative PCR in another set of NFPA samples (n=9). These results may be helpful for evaluating the slow and rapid recurrence of NFPA after surgery and exploring the mechanisms underlying NFPA recurrence. Future effective biomarkers and therapeutic targets may also be revealed.

Comprehensive analysis of lncRNAs N6-methyladenosine modification in colorectal cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) and their N6-methyladenosine (M6A) modifications are involved in cancer occurrence and development.

METHODS

lncRNA M6A modification in colorectal cancer (CRC) was comprehensively analyzed for the first time.

RESULTS

M6A levels of lnRNAs in CRC tissues were higher than those in tumor-adjacent normal tissues. A total of 8,332 M6A peaks were detected in 6,690 lncRNAs in CRC tissues. Approximately 91% of the modified lncRNAs had unique M6A modification peaks. A total of 383 lncRNAs were differentially methylated in CRC, of which 48.24% had a length of 1-1,000 bp. Most of these were located on chromosomes 1, 2, 7, 11, 16 and 19; 42.3% were within a sense-overlapping exon. RNA sequencing identified 163 differentially expressed lncRNAs in CRC. GO and KEGG analyses revealed that genes near differentially-methylated or -expressed lncRNAs were associated with CRC occurrence and development. Methylation was positively correlated with lncRNA expression levels in CRC and tumor-adjacent normal tissues. More unmethylated than M6A methylated lncRNA molecules were detected. A competing endogenous RNA (ceRNA) and lncRNA-mRNA expression-regulation network revealed a regulatory relationship between lncRNAs, microRNAs (miRNAs), and mRNAs.

CONCLUSIONS

The findings may help improve our understanding of lncRNA function in colorectal cancer.

Comprehensive evaluation of differential long non-coding RNA and gene expression in patients with cartilaginous endplate degeneration of cervical vertebra

Long non-coding RNAs (lncRNAs) are emerging as key regulators in gene expression; however, little is currently known regarding their role in cartilaginous endplate (CE) degeneration (CED) of cervical vertebra. The present study aimed to investigate the expression levels of lncRNAs and analyze their potential functions in CED of cervical vertebra in patients with cervical fracture and cervical spondylosis. Human competitive endogenous RNA (ceRNA) array was used to analyze lncRNA and mRNA expression levels in CE samples from patients with cervical fracture and cervical spondylosis, who received anterior cervical discectomy and fusion. Differentially expressed lncRNAs (DELs) or differentially expressed genes (DEGs) were identified and functionally analyzed, using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. An lncRNA-microRNA(miRNA)-mRNA ceRNA regulatory network was constructed based on the DELs and DEGs, and the ceRNA network was visualized using Cytoscape 3.7.2 software. In total, one downregulated mRNA, one upregulated miRNA and five downstream regulated lncRNAs were identified using reverse transcription-quantitative PCR in CED and healthy CE samples. A total of 369 lncRNAs and 246 mRNAs were identified as differentially expressed in CE. The GO and KEGG analyses demonstrated that the majority of GO and KEGG enrichments were associated with CED. Furthermore, a ceRNA network was established, including 168 putative miRNA response elements, 189 upregulated and 37 downregulated lncRNAs and 47 upregulated and 10dow regulated DEGs. The present study analyzed the function of DEGs in the ceRNA network and filtered out the same items as in DEG-function enrichment analysis. These results provide a new perspective for an improved understanding of ceRNA-mediated gene regulation in cervical spondylosis, and provide a novel theoretical basis for further studies on the function of lncRNA in cervical spondylosis. However, further experiments are required to validate the results of the present study.

Epigenetic Mechanisms of LncRNAs Binding to Protein in Carcinogenesis

Simple Summary

The functional analysis of lncRNA, which has recently been investigated in various fields of biological research, is critical to understanding the delicate control of cells and the occurrence of diseases. The interaction between proteins and lncRNA, which has been found to be a major mechanism, has been reported to play an important role in cancer development and progress. This review thus organized the lncRNAs and related proteins involved in the cancer process, from carcinogenesis to metastasis and resistance to chemotherapy, to better understand cancer and to further develop new treatments for it. This will provide a new perspective on clinical cancer diagnosis, prognosis, and treatment.

Abstract

Epigenetic dysregulation is an important feature for cancer initiation and progression. Long non-coding RNAs (lncRNAs) are transcripts that stably present as RNA forms with no translated protein and have lengths larger than 200 nucleotides. LncRNA can epigenetically regulate either oncogenes or tumor suppressor genes. Nowadays, the combined research of lncRNA plus protein analysis is gaining more attention. LncRNA controls gene expression directly by binding to transcription factors of target genes and indirectly by complexing with other proteins to bind to target proteins and cause protein degradation, reduced protein stability, or interference with the binding of other proteins. Various studies have indicated that lncRNA contributes to cancer development by modulating genes epigenetically and studies have been done to determine which proteins are combined with lncRNA and contribute to cancer development. In this review, we look in depth at the epigenetic regulatory function of lncRNAs that are capable of complexing with other proteins in cancer development.

Involvement of Long Non-Coding RNAs (lncRNAs) in Tumor Angiogenesis

Long non-coding RNAs (lncRNAs) are defined as non-protein coding transcripts with a minimal length of 200 nucleotides. They are involved in various biological processes such as cell differentiation, apoptosis, as well as in pathophysiological processes. Numerous studies considered that frequently deregulated lncRNAs contribute to all hallmarks of cancer including metastasis, drug resistance, and angiogenesis. Angiogenesis, the formation of new blood vessels, is crucial for a tumor to receive sufficient amounts of nutrients and oxygen and therefore, to grow and exceed in its size over the diameter of 2 mm. In this review, the regulatory mechanisms of lncRNAs are described, which influence tumor angiogenesis by directly or indirectly regulating oncogenic pathways, interacting with other transcripts such as microRNAs (miRNAs) or modulating the tumor microenvironment. Further, angiogenic lncRNAs occurring in several cancer types such as liver, gastrointestinal cancer, or brain tumors are summarized. Growing evidence on the influence of lncRNAs on tumor angiogenesis verified these transcripts as potential predictive or diagnostic biomarkers or therapeutic targets of anti-angiogenesis treatment. However, there are many unsolved questions left which are pointed out in this review, hence driving comprehensive research in this area is necessary to enable an effective use of lncRNAs as either therapeutic molecules or diagnostic targets in cancer.

Long non-coding RNA LINC00858 aggravates the oncogenic phenotypes of ovarian cancer cells through miR-134-5p/RAD18 signaling

PURPOSE

Ovarian cancer is a common gynecological cancer. Herein, we focused on the function and probable mechanisms of LINC00858 in ovarian cancer.

METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) was employed for detecting the expression of LINC00858, miR-134-5p and RAD18 E3 ubiquitin protein ligase (RAD18). Cell proliferation, migration, invasion, epithelial-mesenchymal transition (EMT) and apoptosis were detected by cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), transwell, terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) and western bolt experiments, as appropriate. Interplays between LINC00858, miR-134-5p and RAD18 were detected by RNA immunoprecipitation (RIP), RNA pull down and luciferase reporter assays.

RESULTS

LINC00858 were up-regulated in ovarian cancer tissues and cells, and its expression was elevated in advanced samples compared to early ones. Knocking down LINC00858 inhibited cell proliferation, motility and EMT, but accelerated cell apoptosis in ovarian cancer. Moreover, could be sponged by LINC00858 sponged miR-134-5p to enhance RAD18 expression in ovarian cancer. Also, silenced RAD18 could also restrain oncogenic behaviors of ovarian cancer cells. Rescue experiments showed that overexpressing RAD18 reversed the effects caused by knocking down LINC00858 on cellular processes.

CONCLUSION

LINC00858 sequestered miR-134-5p to elevate RAD18 expression, resulting in aggravated development of ovarian cancer. This might provide promising targets for treating patients with ovarian cancer.

Long non-coding RNA LINC00858 inhibits colon cancer cell apoptosis, autophagy, and senescence by activating WNK2 promoter methylation

Accumulating evidence shows the involvement of long non-coding RNAs (lncRNAs) in tumorigenesis of many types of human cancers. However, the role of LINC00858 in colon cancer has not been fully elucidated. Therefore, we investigated the involvement of LINC00858 in the progression of colon cancer and identified its downstream targets. After examining the expression of LINC00858 in colon cancer tissues and cell lines, we then identified the possible interaction between LINC00858 and WNK lysine deficient protein kinase 2 (WNK2) by fluorescence in situ hybridization, RNA immunoprecipitation, chromatin immunoprecipitation, and RNA pull-down assays. Next, the role of the LINC00858/WNK2 axis was explored by evaluating the apoptosis, autophagy, and senescence of colon cancer cells in vitro after ectopic expression and depletion experiments in HCT116 cells. Moreover, a mouse xenograft model of HCT116 cells was established to verify the function of the LINC00858/WNK2 axis in vivo. There was high expression of LINC00858 and low expression of WNK2 in colon cancer tissues and cell lines. Silencing of LINC00858 promoted apoptosis, senescence, and autophagy in colon cancer cells. Additionally, the enrichment of WNK2 was promoted when LINC00858 bound to DNA methyltransferases. Furthermore, in vivo assays demonstrated that silencing of LINC00858 resulted in inhibited tumor growth by upregulating WNK2. In summary, LINC00858 acts as a tumor-promoting lncRNA in colon cancer by downregulating WNK2. Our results may provide novel targets for the treatment for colon cancer.

Overexpression of Long Non-Coding RNA FGF14-AS2 Inhibits Colorectal Cancer Proliferation Via the RERG/Ras/ERK Signaling by Sponging microRNA-1288-3p

Colorectal cancer remains one of most common cancer types with poor prognosis globally. Recent years, numerous studies depicted pivotal roles of lncRNAs in colorectal cancer progression. This study aimed to investigate the role of FGF14-AS2 in colorectal cancer development. FGF14-AS2 was found as a significantly downregulated lncRNA in TCGA dataset. Via RT-qPCR, we confirmed the downregulation of FGF14-AS2 in collected colorectal carcinoma samples. Transfection of plasmid containing full length of FGF14-AS2 repressed cell proliferation and induced elevation of cell apoptosis in colorectal cancer cells. In addition, FGF14-AS2 overexpression inactivated MAPK/ERK signaling in cells. Bioinformatic analysis and subsequent cell-based assays showed that FGF14-AS2 sponging miR-1288-3p, an oncogenic miRNA in colorectal cancer. RERG, the regulator of Ras/ERK pathway, was predicted and verified as target gene of miR-1288. Via downregulation of miR-1288, FGF14-AS2 elevated RERG expression in colorectal cancer cells. Rescue assays indicated that FGF14-AS2 relied on regulation of RERG to control cell proliferation and apoptosis in colorectal cancer. Taken together, the current study demonstrated FGF14-AS2 as a regulator of colorectal cancer development via downregulation of miR-1288-3p and inactivation of Ras/ERK signaling.