Knockdown of long non-coding RNA KCNQ1OT1 depressed chemoresistance to paclitaxel in lung adenocarcinoma

A review on the role of KCNQ1OT1 lncRNA in human disorders

KCNQ1OT1 is an lncRNA located within KCNQ1 gene on chromosome 11p15.5. This lncRNAs participates in the pathogenesis of a diversity of cancers as well as non-cancerous conditions. In most types of cancers, KCNQ1OT1 is regarded as an oncogene. In a wide array of cancers, high level of KCNQ1OT1 is associated with lower overall survival time. This lncRNA has been found to adsorb a variety of miRNAs, namely miR-15a, miR-211-5p, hsa-miR-107, miR-145, miR-34a, miR-204-5p, miR-129-5p, miR-372-3p, miR-491-5p, miR-153, miR-185-5p, miR-124-3p, miR-211-5p, miR-149, miR-148a-3p, miR-140-5p, miR-125b-5p, miR-9, miR-329-3p, miR-760, miR-296-5p, miR-3666 and miR-129-5p, thus regulating the downstream targets of these miRNAs. In this manuscript, our attention is on this lncRNA and its biomolecular roles in human cancers and other disorders. KCNQ1OT1 plays significant roles in the tumorigenesis and may function as a prospective target for cancer therapy.

Biological role of long non-coding RNA KCNQ1OT1 in cancer progression

Long non-coding RNAs (lncRNAs) are a type of RNAs that are more than 200 nucleotides without protein-coding potential. In recent years, more and more attention has been paid to the role of lncRNAs in cancer pathogenesis. LncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) is located on chromosome 11p15.5 with a total length of 91 kb and is highly expressed in various malignancies, which is closely related to tumor growth, lymph node metastasis, survival cycle and recurrence rate. In addition, KCNQ1OT1 is involved in the regulation of PI3K/AKT and Wnt/β-catenin signaling pathways. In this review, the mechanism and related progress of KCNQ1OT1 in different cancers were reviewed. It was found that KCNQ1OT1 can stabilize mRNA expression through sponging miRNA, which not only induced tumor cell proliferation, migration, invasion, drug resistance, epithelial-mesenchymal transition (EMT) and inhibited cell apoptosis in vitro, but also promoted tumor growth and metastasis in vivo. Therefore, as a new biomarker and therapeutic target, KCNQ1OT1 has broad prospects for the diagnosis and treatment of different cancers.

Ion Channels as Potential Tools for the Diagnosis, Prognosis, and Treatment of HPV-Associated Cancers

The human papilloma virus (HPV) group comprises approximately 200 genetic types that have a special affinity for epithelial tissues and can vary from producing benign symptoms to developing into complicated pathologies, such as cancer. The HPV replicative cycle affects various cellular and molecular processes, including DNA insertions and methylation and relevant pathways related to pRb and p53, as well as ion channel expression or function. Ion channels are responsible for the flow of ions across cell membranes and play very important roles in human physiology, including the regulation of ion homeostasis, electrical excitability, and cell signaling. However, when ion channel function or expression is altered, the channels can trigger a wide range of channelopathies, including cancer. In consequence, the up- or down-regulation of ion channels in cancer makes them attractive molecular markers for the diagnosis, prognosis, and treatment of the disease. Interestingly, the activity or expression of several ion channels is dysregulated in HPV-associated cancers. Here, we review the status of ion channels and their regulation in HPV-associated cancers and discuss the potential molecular mechanisms involved. Understanding the dynamics of ion channels in these cancers should help to improve early diagnosis, prognosis, and treatment in the benefit of HPV-associated cancer patients.

Noncoding RNAs in cataract formation: star molecules emerge in an endless stream

For decades, research on the pathological mechanism of cataracts has usually focused on the abnormal protein changes caused by a series of risk factors. However, an entire class of molecules, termed non-coding RNA (ncRNA), was discovered in recent years and proven to be heavily involved in cataract formation. Recent studies have recognized the key regulatory roles of ncRNAs in cataracts by shaping cellular activities such as proliferation, apoptosis, migration and epithelial-mesenchymal transition (EMT). This review summarizes our current insight into the biogenesis, properties and functions of ncRNAs and then discusses the development of research on ncRNAs in cataracts. Considering the significant role of ncRNA in cataract formation, research on novel associated regulatory mechanisms is urgently needed, and the development of therapeutic alternatives for the treatment of cataracts seems promising.

LncRNA KCNQ1OT1 contributes to hydrogen peroxide-induced apoptosis, inflammation, and oxidative stress of cardiomyocytes via miR-130a-3p/ZNF791 axis

It has been reported that long noncoding RNA (lncRNA) KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) played an important role in myocardial infarction (MI). However, the regulatory network behind KCNQ1OT1 in MI is largely unknown. Quantitative real time polymerase chain reaction (qRT-PCR) was applied to detect the enrichment of KCNQ1OT1, microRNA-130a-3p (miR-130a-3p) and zinc finger 791 (ZNF791). The viability and apoptosis of AC16 cells were measured by (4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. Enzyme-linked immunosorbent assay (ELISA) was conducted to assess the inflammation and oxidative stress status of AC16 cells. The targeted relationship between miR-130a-3p and KCNQ1OT1 or ZNF791 was predicted by StarBase bioinformatic database, and dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were carried out to verify these predictions. Hydrogen peroxide (H₂ O₂ ) stimulation caused a significant upregulation in the expression of KCNQ1OT1, while the level of miR-130a-3p showed an opposite phenomenon. KCNQ1OT1 was a crucial downstream component in H₂ O₂ -mediated toxic effects, and KCNQ1OT1 accelerated H₂ O₂ -induced toxic effects in AC16 cells. KCNQ1OT1 could sponge miR-130a-3p and down-regulate its expression. MiR-130a-3p exerted opposite effects to KCNQ1OT1, and the depletion of miR-130a-3p attenuated the protective effects of KCNQ1OT1 intervention on AC16 cells exposed to H₂ O₂ . MiR-130a-3p could bind to ZNF791, and ZNF791 served as the target of miR-130a-3p to promote H₂ O₂ -induced injury of AC16 cells. ZNF791 was modulated by KCNQ1OT1/miR-130a-3p signaling in H₂ O₂ -treated AC16 cells. In all, lncRNA KCNQ1OT1 deteriorated H₂ O₂ -mediated injury in cardiomyocytes through upregulating ZNF791 via serving as a molecular sponge for miR-130a-3p.

Noncoding RNAs and their therapeutics in paclitaxel chemotherapy: Mechanisms of initiation, progression, and drug sensitivity

The identification of agents that can reverse drug resistance in cancer chemotherapy, and enhance the overall efficacy is of great interest. Paclitaxel (PTX) belongs to taxane family that exerts an antitumor effect by stabilizing microtubules and inhibiting cell cycle progression. However, PTX resistance often develops in tumors due to the overexpression of drug transporters and tumor-promoting pathways. Noncoding RNAs (ncRNAs) are modulators of many processes in cancer cells, such as apoptosis, migration, differentiation, and angiogenesis. In the present study, we summarize the effects of ncRNAs on PTX chemotherapy. MicroRNAs (miRNAs) can have opposite effects on PTX resistance (stimulation or inhibition) via influencing YES1, SK2, MRP1, and STAT3. Moreover, miRNAs modulate the growth and migration rates of tumor cells in regulating PTX efficacy. PIWI-interacting RNAs, small interfering RNAs, and short-hairpin RNAs are other members of ncRNAs regulating PTX sensitivity of cancer cells. Long noncoding RNAs (LncRNAs) are similar to miRNAs and can modulate PTX resistance/sensitivity by their influence on miRNAs and drug efflux transport. The cytotoxicity of PTX against tumor cells can also be affected by circular RNAs (circRNAs) and limitation is that oncogenic circRNAs have been emphasized and experiments should also focus on onco-suppressor circRNAs.

lncRNA KCNQ1OT1 Promotes EMT, Angiogenesis, and Stemness of Pituitary Adenoma by Upregulation of RAB11A

This study is aimed at investigating the effect and mechanism of long noncoding RNA (lncRNA) KCNQ1OT1 on pituitary adenoma (PA). The KCNQ1OT1 expression in invasive and noninvasive PA tissues was detected by real-time fluorescence quantitative polymerase chain reaction (qPCR). The effects of KCNQ1OT1 on the proliferation of PA cells, namely, GH3 and HP75, were detected by CCK-8 experiment. The Transwell assay detected the effect of KCNQ1OT1 on the invasion of GH3 and HP75 cells. The effect of KCNQ1OT1 on the clonal formation ability was detected by clonal formation experiment. The double luciferase reporter assay and the miRNA pull down assay verified the binding of KCNQ1OT1 to miR-140-5p. Meanwhile, the regulatory effect of miR-140-5p on RAB11A was verified. qPCR results showed that KCNQ1OT1 was significantly increased in invasive PA compared with noninvasive PA tissues. Knockdown KCNQ1OT1 inhibited PA cell stemness, angiogenesis, and EMT. In addition, knockdown KCNQ1OT1 inhibited the proliferation, invasion, and clonal formation of PA. miR-140-5p is the target gene of KCNQ1OT1. miR-140-5p targets RAB11A directly. RAB11A can mediate the biological effects of KCNQ1OT1. Meanwhile, lncRNA KCNQ1OT1 can promote the EMT and cellular stemness of PA. Its mechanism of action is realized by inhibiting miR-140-5p. This result can provide a molecular basis for the further study of PA.

KCNQ1OT1 polymorphism rs35622507 and methylation status of KCNQ1OT1 promoter influence the drug resistance to L-OHP

Background: LncRNA potassium voltage-gated channel subfamily Q member 1 opposite strand/antisense transcript 1 (KCNQ1OT1) has been reported to promote resistance to chemotherapy in colon cancer by inhibiting the expression of miR-34a. And the methylation of KCNQ1OT1 was also reported in the pathogenesis of various diseases. In this study, we aimed to study the combined effect of allele variation of KCNQ1OT1 polymorphism rs35622507 and methylation status of KCNQ1OT1 promoter in the treatment of colon cancer.

Methods: The expression levels of KCNQ1OT1, miR-34a, and ATG4B mRNA were assessed by qRT-PCR. ATG4B protein expression was analyzed by Western blot analysis. TUNEL and MTT assay were performed to examine the cell apoptosis and viability. Luciferase assays revealed the relationship between KCNQ1OT1, miR-34a and ATG4B.

Results: Carrier of allele 10 and methylated promoter in KCNQ1OT1 was associated with decreased KCNQ1OT1/ATG4B expression, increased miR-34a expression and enhanced apoptosis in colon cancer tissue samples. And subsequent luciferase assay showed that miR-34a could bind to KCNQ1OT1 and ATG4B at specific binding sites. The knockdown of KCNQ1OT1 significantly suppressed the KCNQ1OT1/ATG4B expression, improved the miR-34a expression and reduced the viability of HCT116 and SW480 cells. The over-expression of ATG4B notably restored the cell viability loss and apoptosis increase induced by the knockdown of KCNQ1OT1. Moreover, oxaliplatin (L-OHP) treatment elevated the apoptosis of HCT116 and SW480 cells.

Conclusions: The drug resistance in the treatment of colon cancer is most reduced in patients carrying allele 10 and methylated in KCNQ1OT1 promoter. This function is accomplished by the signaling pathway of KCNQ1OT1/miR-34a/ATG4B.

Long non-coding RNAs as the critical regulators of epithelial mesenchymal transition in colorectal tumor cells: an overview

Colorectal cancer (CRC) is the second most common cause of cancer mortality and a major health challenge worldwide. Despite advances in therapeutic and diagnostic methods, there is still a poor prognosis in CRC patients. Tumor recurrence and metastasis are the main causes of high mortality rate in these patients, which are due to late diagnosis in advanced tumor stages. Epithelial-mesenchymal transition (EMT) is known to be the most important cause of CRC metastasis, during which tumor cells obtain metastasis ability by losing epithelial features and gaining mesenchymal features. Long non-coding RNAs (lncRNAs) are pivotal regulators of EMT process. Regarding the higher stability of lncRNAs compared with coding RNAs in body fluids, they can be used as non-invasive diagnostic markers for EMT process. In the present review, we summarized all of the lncRNAs involved in regulation of EMT process during CRC progression and metastasis. It was observed that lncRNAs mainly induced the EMT process in CRC cells by regulation of EMT-related transcription factors, Poly comb repressive complex (PRC), and also signaling pathways such as WNT, NOTCH, MAPK, and Hippo.

The pleiotropic roles of circular and long noncoding RNAs in cutaneous melanoma

Cutaneous melanoma (CM) is a very aggressive disease, often characterized by unresponsiveness to conventional therapies and high mortality rates worldwide. The identification of the activating BRAFV600 mutations in approximately 50% of CM patients has recently fueled the development of novel small-molecule inhibitors that specifically target BRAFV600 -mutant CM. In addition, a major progress in CM treatment has been made by monoclonal antibodies that regulate the immune checkpoint inhibitors. However, although target-based therapies and immunotherapeutic strategies have yielded promising results, CM treatment remains a major challenge. In the last decade, accumulating evidence points to the aberrant expression of different types of noncoding RNAs (ncRNAs) in CM. While studies on microRNAs have grown exponentially leading to significant insights on CM biology, the role of circular RNAs (circRNAs) and long noncoding RNAs (lncRNAs) in this tumor is less understood, and much remains to be discovered. Here, we summarize and critically review the available evidence on the molecular functions of circRNAs and lncRNAs in BRAFV600 -mutant CM and CM immunogenicity, providing recent updates on their functional role in targeted therapy and immunotherapy resistance. In addition, we also include an evaluation of several algorithms and databases for prediction and validation of circRNA and lncRNA functional interactions.

A Review on CRISPR-Mediated Epigenome Editing: A Future Directive for Therapeutic Management of Cancer

Abstract:

Recent studies have shed light on the role of epigenetic marks in certain diseases like cancer, type II diabetes mellitus (T2DM), obesity, and cardiovascular dysfunction, to name a few. Epigenetic marks like DNA methylation and histone acetylation are randomly altered in the disease state. It has been seen that methylation of DNA and histones can result in down-regulation of gene expression, whereas histone acetylation, ubiquitination, and phosphorylation are linked to enhanced expression of genes. How can we precisely target such epigenetic aberrations to prevent the advent of diseases? The answer lies in the amalgamation of the efficient genome editing technique, CRISPR, with certain effector molecules that can alter the status of epigenetic marks as well as employ certain transcriptional activators or repressors. In this review, we have discussed the rationale of epigenetic editing as a therapeutic strategy and how CRISPR-Cas9 technology coupled with epigenetic effector tags can efficiently edit epigenetic targets. In the later part, we have discussed how certain epigenetic effectors are tagged with dCas9 to elicit epigenetic changes in cancer. Increased interest in exploring the epigenetic background of cancer and non-communicable diseases like type II diabetes mellitus and obesity accompanied with technological breakthroughs has made it possible to perform large-scale epigenome studies.

KCNQ1OT1: An Oncogenic Long Noncoding RNA

Long noncoding RNAs (lncRNAs) are transcripts greater than 200 nucleotides that do not code for proteins but regulate gene expression. Recent studies indicate that lncRNAs are involved in the modulation of biological functions in human disease. KCNQ1 Opposite Strand/Antisense Transcript 1 (KCNQ1OT1) encodes a lncRNA from the opposite strand of KCNQ1 in the CDKN1C/KCNQ1OT1 cluster that is reported to play a vital role in the development and progression of cancer. KCNQ1OT1 regulates cancer cell proliferation, cell cycle, migration and invasion, metastasis, glucose metabolism, and immune evasion. The aberrant expression of KCNQ1OT1 in cancer patients is associated with poor prognosis and decreased survival. This review summarizes recent literature related to the biological functions and molecular mechanisms of KCNQ1OT1 in various human cancers, including colorectal, bladder, breast, oral, melanoma, osteosarcoma, lung, glioma, ovarian, liver, acute myeloid leukemia, prostate, and gastric. We also discuss the role of KCNQ1OT1 as a promising diagnostic biomarker and a novel therapeutic target in human cancers.

LncRNA KCNQ1OT1 activated by c-Myc promotes cell proliferation via interacting with FUS to stabilize MAP3K1 in acute promyelocytic leukemia

Uncontrolled proliferation is the hallmark of cancer cells. Previous studies mainly focused on the role of protein-coding genes in cancer cell proliferation. Emerging evidence showed that long non-coding RNAs (lncRNAs) also play critical roles in cancer cell proliferation and growth. LncRNA KCNQ1OT1 is found to contribute to carcinogenesis, but its role in acute promyelocytic leukemia (APL) is unclear. In this study, by analyzing data from Gene Expression Omnibus, The Cancer Genome Atlas database and our clinical samples, we found that KCNQ1OT1 was selectively highly expressed in APL. Functional assays demonstrated that knockdown of KCNQ1OT1 reduced APL cell proliferation and increased apoptosis. Further evidence showed that KCNQ1OT1 was mainly located in the cytoplasm of APL patient-derived NB4 cells and APL patient bone marrow samples. Mechanistically, KCNQ1OT1 bound to RNA binding protein FUS, and silencing either KCNQ1OT1 or FUS reduced the expression level and stability of MAP3K1 mRNA. Whereas KCNQ1OT1 and FUS did not affect each other. Importantly, knockdown of MAP3K1 impaired APL cell proliferation. Finally, c-Myc transactivated KCNQ1OT1 in APL cells through binding to its promoter while knockdown of c-Myc decreased KCNQ1OT1 expression. Our results not only revealed that c-Myc transactivated KCNQ1OT1 and upregulated KCNQ1OT1 promoted APL cell proliferation, but also demonstrated that KCNQ1OT1 bound to FUS to synergistically stabilize MAP3K1 mRNA, thus facilitating APL cell proliferation. This study established a previously unidentified role of KCNQ1OT1 in the development of APL, and KCNQ1OT1 may serve as a potential therapeutic target for APL.

Silencing of long non-coding RNA KCNQ1OT1 alleviates LPS-induced lung injury by regulating the miR-370-3p/FOXM1 axis in childhood pneumonia

Purpose

Long non-coding RNAs (lncRNAs) play important roles in the development of pneumonia. We aimed to explore the role of the lncRNA KCNQ1OT1 in pneumonia and its underlying mechanisms.

Methods

The expression of KCNQ1OT1, FOXM1, and miR-370-3p was detected in the serum of 24 children with pneumonia and in 24 healthy controls. Normal human embryonic lung-derived diploid fibroblasts (WI-38 cells) were stimulated with LPS (10 μg/mL) to simulate the cellular model of pneumonia, and cell viability, apoptosis, and inflammation were analysed. Dual luciferase reporter and/or RNA binding protein immunoprecipitation assays were performed to test the relationship between miR-370-3p and KCNQ1OT1/FOXM1. Mice were intratracheally administered LPS (5 mg/kg) to induce an in vivo model of pneumonia, and pathological injury and inflammation were analysed.

Results

The expression of KCNQ1OT1 and FOXM1 was up-regulated, and miR-370-3p was down-regulated in the serum of children with pneumonia, LPS-treated WI-38 cells, and in lung tissues of LPS-treated mice. Silencing of KCNQ1OT1 or overexpression of miR-370-3p suppressed cell apoptosis and inflammation and facilitated cell viability in LPS-treated WI-38 cells. KCNQ1OT1 directly targets miR-370-3p and negatively regulates its expression. FOXM1 was targeted by miR-370-3p and negatively modulated by miR-370-3p. In addition, silencing of KCNQ1OT1 mitigated LPS-induced lung injury and inflammation in mice. The protective effects of KCNQ1OT1 silencing in LPS-treated WI-38 cells and mice were reversed by silencing of miR-370-3p or overexpression of FOXM1.

Conclusion

Silencing of KCNQ1OT1 alleviates LPS-induced lung injury by regulating the miR-370-3p/FOXM1 axis in pneumonia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01609-0.

Long non-coding RNA KCNQ1OT1 promotes the progression of gastric cancer via the miR-145-5p/ARF6 axis

BACKGROUND

Long non-coding RNA KCNQ1 opposite strand/antisense transcript one gene (KCNQ1OT1) has been reported to be involved in the progression of many types of human cancer, whereas its role in gastric cancer (GC) remains unknown. The present study aimed to investigate the role of KCNQ1OT1 in GC.

METHODS

In total, 25 GC tissues and adjacent normal tissues were collected. The expression of KCNQ1OT1, miR-145-5p and ARF6 in GC tissues and cell lines was detected by quantitative reverse transcriptase-polymerase chain reaction or western blotting. Bioinformatics analysis and a dual luciferase reporter assay were performed to determine the relationship between KCNQ1OT1 and miR-145-5p or miR-145-5p and ARF6. Gain- and loss-of function of KCNQ1OT1 and miR-145-5p were achieved to confirm their roles in GC cells. Cell counting kit-8, colony formation and flow cytometry assays were used to evaluate cell viability, proliferation and apoptosis. A xenograft tumor model was established with BGC803 tumor cells transfected with sh-KCNQ1OT1 or empty vector to determine the role of LINC01089 in vivo.

RESULTS

The expression levels of KCNQ1OT1 were markedly elevated in GC tissues and cells. Knockdown of KCNQ1OT1 inhibited GC tumor growth, reduced GC cell viability and colony formation, and induced GC cell apoptosis. The expression levels of miR-145-5p were significantly decreased in GC cells and correlated with the expression of KCNQ1OT1 in GC tumors. Moreover, KCNQ1OT1 directly binds with miR-145-5p, which is targeting ARF6. Knockdown of KCNQ1OT1 increased the expression levels of miR-145-5p. Inhibition of miR-145-5p increased the expression levels of KCNQ1OT1 and also attenuated the effects of knockdown of KCNQ1OT1 on the viability, proliferation and apoptosis of GC cells. In addition, overexpression of miR-145-5p reduced GC cell viability and colony formation and induced GC cell apoptosis, whereas overexpression of ARF6 attenuated the effects of overexpression of miR-145-5p on GC cell viability, colony formation and apoptosis.

CONCLUSIONS

KCNQ1OT1 can promote GC progression through the miR-145-5p/ARF6 axis. KCNQ1OT1 may serve as a therapeutic target and a diagnostic biomarker of GC.

The function of LncRNAs and their role in the prediction, diagnosis, and prognosis of lung cancer

Lung cancer remains a major threat to human health. Low dose CT scan (LDCT) has become the main method of early screening for lung cancer due to the low sensitivity of chest X-ray. However, LDCT not only has a high false positive rate, but also entails risks of overdiagnosis and cumulative radiation exposure. In addition, cumulative radiation by LDCT screening and subsequent follow-up can increase the risk of lung cancer. Many studies have shown that long noncoding RNAs (lncRNAs) remain stable in blood, and profiling of blood has the advantages of being noninvasive, readily accessible and inexpensive. Serum or plasma assay of lncRNAs in blood can be used as a novel detection method to assist LDCT while improving the accuracy of early lung cancer screening. LncRNAs can participate in the regulation of various biological processes. A large number of researches have reported that lncRNAs are key regulators involved in the progression of human cancers through multiple action models. Especially, some lncRNAs can affect various hallmarks of lung cancer. In addition to their diagnostic value, lncRNAs also possess promising potential in other clinical applications toward lung cancer. LncRNAs can be used as predictive markers for chemosensitivity, radiosensitivity, and sensitivity to epidermal growth factor receptor (EGFR)-targeted therapy, and as well markers of prognosis. Different lncRNAs have been implicated to regulate chemosensitivity, radiosensitivity, and sensitivity to EGFR-targeted therapy through diverse mechanisms. Although many challenges need to be addressed in the future, lncRNAs have bright prospects as an adjunct to radiographic methods in the clinical management of lung cancer.

Long Non-coding RNAs in Cisplatin Resistance in Osteosarcoma

OPINION STATEMENT

Osteosarcoma (OS), the most common primary malignant bone tumor, is a vastly aggressive disease in children and adolescents. Although dramatic progress in therapeutic strategies have achieved over the past several decades, the outcome remains poor for most patients with metastatic or recurrent OS. Nowadays, conventional treatment for OS patients is surgery combined with multidrug chemotherapy including doxorubicin, methotrexate, and cisplatin (CDDP). In this sense, cisplatin (CDDP) is one of the most drugs used in the treatment of OS but drug resistance to CDDP appears as a serious problem in the use of this drug in the treatment of OS. Thus, we consider that the understanding the molecular mechanisms and the genes involved that lead to CDDP resistance is essential to developing more effective treatments against OS. In this review, we present an outline of the key role of the long non-coding RNAs (lncRNAs) in CDDP resistance in OS. This overview is expected to contribute to understand the mechanisms of CDDP resistance in OS and the relationship of the expression regulation of several lncRNAs.

CRISPR-dCas9-Based Artificial Transcription Factors to Improve Efficacy of Cancer Treatment With Drug Repurposing: Proposal for Future Research

Due to the high resistance that cancer has shown to conventional therapies, it is difficult to treat this disease, particularly in advanced stages. In recent decades, treatments have been improved, being more specific according to the characteristics of the tumor, becoming more effective, less toxic, and invasive. Cancer can be treated by the combination of surgery, radiation therapy, and/or drug administration, but therapies based on anticancer drugs are the main cancer treatment. Cancer drug development requires long-time preclinical and clinical studies and is not cost-effective. Drug repurposing is an alternative for cancer therapies development since it is faster, safer, easier, cheaper, and repurposed drugs do not have serious side effects. However, cancer is a complex, heterogeneous, and highly dynamic disease with multiple evolving molecular constituents. This tumor heterogeneity causes several resistance mechanisms in cancer therapies, mainly the target mutation. The CRISPR-dCas9-based artificial transcription factors (ATFs) could be used in cancer therapy due to their possibility to manipulate DNA to modify target genes, activate tumor suppressor genes, silence oncogenes, and tumor resistance mechanisms for targeted therapy. In addition, drug repurposing combined with the use of CRISPR-dCas9-based ATFs could be an alternative cancer treatment to reduce cancer mortality. The aim of this review is to describe the potential of the repurposed drugs combined with CRISPR-dCas9-based ATFs to improve the efficacy of cancer treatment, discussing the possible advantages and disadvantages.

Role of non-coding RNAs in modulating the response of cancer cells to paclitaxel treatment

Paclitaxel is a chemotherapeutic substance that is administered for treatment of an extensive spectrum of human malignancies. In spite of its potent short-term effects against tumor cells, resistance to paclitaxel occurs in a number of patients precluding its long-term application in these patients. Non-coding RNAs have been shown to influence response of cancer cells to this chemotherapeutic agent via different mechanisms. Mechanistically, these transcripts regulate expression of several genes particularly those being involved in the apoptotic processes. Lots of in vivo and in vitro assays have demonstrated the efficacy of oligonucleotide-mediated microRNAs (miRNA)/ long non-coding RNAs (lncRNA) silencing in enhancement of response of cancer cells to paclitaxel. Therefore, targeted therapies against non-coding RNAs have been suggested as applicable modalities for combatting resistance to this agent. In the present review, we provide a summary of studies which assessed the role of miRNAs and lncRNAs in conferring resistance to paclitaxel.

The role of long non-coding RNAs in mediating chemoresistance by modulating autophagy in cancer

Cancer is a complex process in which protein-coding and non-coding genes play essential roles. Long noncoding RNAs (lncRNAs), as a subclass of noncoding genes, are implicated in various cancer processes including growth, proliferation, metastasis, and angiogenesis. Due to presence in body fluids such as blood and urine, lncRNAs have become novel biomarkers in cancer detection, diagnosis, progression, and therapy response. Remarkably, increasing evidence has verified that lncRNAs play essential roles in chemoresistance by targeting different signalling pathways. Autophagy, a highly conserved process in response to environmental stresses such as starvation and hypoxia, plays a paradoxical role in inducing resistance or sensitivity to chemotherapy agents. In this regard, we reviewed chemoresistance, the role of lncRNAs in cancer, and the role of lncRNAs in chemoresistance by modulating autophagy.

PNN and KCNQ1OT1 Can Predict the Efficacy of Adjuvant Fluoropyrimidine-Based Chemotherapy in Colorectal Cancer Patients

The benefit of adjuvant chemotherapy in the early stages of colorectal cancer (CRC) is still disappointing and the prediction of treatment outcome quite difficult. Recently, through a transcriptomic approach, we evidenced a role of PNN and KCNQ1OT1 gene expression in predicting response to fluoropyrimidine-based adjuvant chemotherapy in stage III CRC patients. Thus, the aim of this study was to validate in an independent cohort of stages II–III CRC patients our previous findings. PNN and KCNQ1OT1 mRNA expression levels were evaluated in 74 formalin-fixed paraffin-embedded tumor and matched normal mucosa samples obtained by stages II–III CRC patients treated with fluoropyrimidine-based adjuvant chemotherapy. PININ, the protein encoded by PNN, was immunohistochemically evaluated in 15 tumor and corresponding normal mucosa samples, selected on the basis of a low, medium, or high mRNA expression tumor/mucosa ratio. PNN and KCNQ1OT1 mRNA mean expression levels were significantly higher in tumor compared with normal tissues. Patients with high PNN or KCNQ1OT1 tumor mRNA levels according to ROC-based cutoffs showed a shorter disease-free survival (DFS) compared with patients with low tumor mRNA gene expression. Also, patients with tumor mRNA expression values of both genes below the identified cutoffs had a significantly longer DFS compared with patients with the expression of one or both genes above the cutoffs. In a representative large cohort of stages II–III CRC untreated patients retrieved from GEO datasets, no difference in DFS was observed between patients with high and low PNN or KCNQ1OT1 gene expression levels. These data confirm our previous findings and underscore the relevance of PNN and KCNQ1OT1 expression in predicting DFS in early stages of CRC treated with fluoropyrimidine-based adjuvant chemotherapy. If further validated in a prospective case series, both biomarkers could be used to identify patients who benefit from this treatment and to offer alternative chemotherapy regimens to potential unresponsive patients. In relation to the suggested biological role of PNN and KCNQ1OT1 in CRC, they might also be exploited as potential therapeutic targets.

Upregulation of KCNQ1OT1 promotes resistance to stereotactic body radiotherapy in lung adenocarcinoma by inducing ATG5/ATG12-mediated autophagy via miR-372-3p

Stereotactic body radiotherapy (SBRT) has emerged as a standard treatment for non-small-cell lung cancer. However, its therapeutic advantages are limited with the development of SBRT resistance. The SBRT-resistant cell lines (A549/IR and H1975/IR) were established after exposure with hypofractionated irradiation. The differential lncRNAs were screened by microarray assay, then the expression was detected in LUAD tumor tissues and cell lines by qPCR. The influence on radiation response was assessed via in vitro and in vivo assays, and autophagy levels were evaluated by western blot and transmission electron microscopy. Bioinformatics prediction and rescue experiments were used to identify the pathways underlying SBRT resistance. High expression of KCNQ1OT1 was identified in LUAD SBRT-resistant cells and tissues, positively associated with a large tumor, advanced clinical stage, and a lower response rate to concurrent therapy. KCNQ1OT1 depletion significantly resensitized A549/IR and H1975/IR cells to radiation by inhibiting autophagy, which could be attenuated by miR-372-3p knockdown. Furthermore, autophagy-related 5 (ATG5) and autophagy-related 12 (ATG12) were confirmed as direct targets of miR-372-3p. Restoration of either ATG5 or ATG12 abrogated miR-372-3p-mediated autophagy inhibition and radiosensitivity. Our data describe that KCNQ1OT1 is responsible for SBRT resistance in LUAD through induction of ATG5- and ATG12-dependent autophagy via sponging miR-372-3p, which would be a potential strategy to enhance the antitumor effects of radiotherapy in LUAD.

lncRNA KCNQ1OT1 promotes the proliferation, migration and invasion of retinoblastoma cells by upregulating HIF-1α via sponging miR-153-3p

It is reported that lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) is oncogenic in many cancers. This work aimed at probing into its expression and biological functions in retinoblastoma (RB) as well as its regulatory effects on miR-153-3p and hypoxia-inducible factor-1α (HIF-1α). In our study, RB samples in pair were collected, and quantitative real-time PCR (qRT-PCR) was employed for examining the expression levels of KCNQ1OT1, miR-153-3p and HIF-1α. KCNQ1OT1 short hairpin RNAs were transfected into SO-Rb50 and HXO-RB44 cell to inhibit the expression of KCNQ1OT1. The proliferative activity, colony formation ability and apoptosis were examined through cell counting kit-8 assay, colony formation assays, Transwell assay and flow cytometry, respectively. qRT-PCR and western blot analysis were used for analyzing the changes of miR-153-3p and HIF-1α induced by KCNQ1OT1. The regulatory relationships between miR-153-3p and KCNQ1OT1, miR-153-3p and HIF-1α were examined by dual luciferase reporter gene assay and RNA-binding protein immunoprecipitation assay. The results of our study showed that KCNQ1OT1 expression was markedly enhanced in RB tissue samples, and KCNQ1OT1 knockdown had an inhibitory effect on the proliferation, migration, invasion and viability of RB cells. There were two validated binding sties between KCNQ1OT1 and miR-153-3p, and KCNQ1OT1 negatively regulated the expression of miR-153-3p in RB cells. HIF-1α was a target gene of miR-153-3p, and could be positively regulated by KCNQ1OT1. In conclusion, our study indicates that KCNQ1OT1 can increase the malignancy of RB cells via regulating miR-153-3p/HIF-1α axis.

The functions of LncRNA in the heart

Cardiovascular disease is a major cause of death and disability worldwide. Recently, increasing evidence has demonstrated that various lncRNAs play critical roles in the pathogenesis of cardiovascular diseases, including myocardial ischemia and reperfusion (I/R) injury. LncRNAs are transcripts longer than 200 nucleotides. They are considered a class of dynamic noncoding RNAs known to be involved in physiological and pathological conditions with regulatory and structural roles in numerous biological processes, including genomic imprinting, epigenetic regulation, cell proliferation, development, aging and apoptosis. They are emerging as potential key regulators of a variety of cardiovascular diseases. However, the roles of lncRNAs in the heart function remain largely unknown. The purpose of this review was to summarize the functions of lncRNAs in the heart and discuss the challenges and possible strategies of lncRNA research for cardiovascular disease.

Long Non-Coding RNA KCNQ1OT1 Promotes Multidrug Resistance in Chordoma by Functioning as a Molecular Sponge of miR-27b-3p and Subsequently Increasing ATF2 Expression

Background

Chordoma, a rare bone tumor, occurs most commonly at the sacrococcygeal and skull base region. To date, chemotherapy is used to treat patients with advanced-stage chordoma. However, multidrug resistance (MDR) greatly hinders the effect of chemotherapy in chordoma. Here, we studied the correlation between KCNQ1OT1 and chemotherapy resistance.

Methods

RT-PCR assay was used to examine KCNQ1OT1, miR-27b-3p, and ATF2 mRNA expression. CCK8 assay was exercised to detect IC₅₀ values of cisplatin in chordoma cells. ATF2 protein expression was detected by Western blot.

Results

KCNQ1OT1 was increased in chemotherapy-resistant patients and cisplatin-resistant cells, and downregulation of KCNQ1OT1 expression weakened MDR in chordoma. In addition, KCNQ1OT1 promoted MDR in chordoma by sponging miR-27b-3p and subsequently increasing ATF2 expression.

Conclusion

KCNQ1OT1 is proved to be strikingly raised in the chemotherapy-resistant group and to promote MDR in chordoma. Our findings demonstrated the role of the KCNQ1OT1/miR-27b-3p/ATF2 axis in MDR of chordoma, which provides new insight into the molecular mechanism of chordoma MDR, and may determine the effect of therapy after receiving chemotherapy by detecting the expression of KCNQ1OT1 in serum.

Long Noncoding RNA KCNQ1OT1 Confers Gliomas Resistance to Temozolomide and Enhances Cell Growth by Retrieving PIM1 From miR-761

Many studies have found that the dysregulation of long noncoding RNA (lncRNA) contributed to cancer initiation, progression, and recurrence via multiple signaling pathways. However, the underlying mechanisms of lncRNA in temozolomide (TMZ)-resistant gliomas were not well understood, hindering the improvement of TMZ-based therapies. The present study demonstrated that the lncRNA KCNQ1OT1 increased in TMZ-resistant glioma cells compared to the TMZ-sensitive cells. The introduction of KCNQ1OT1 promoted cell viability, clonogenicity, and rhodamine 123 efflux while hampering TMZ-induced apoptosis. Moreover, KCNQ1OT1 directly sponged miR-761, which decreased in TMZ-resistant sublines. The overexpression of miR-761 attenuated cell viability and clonogenicity, while triggering apoptosis and rhodamine 123 accumulation post-TMZ exposure, leading to a response to TMZ. The interaction between miR-761 and 3'-untranslated region of PIM1 attenuated PIM1-mediated signaling cascades. Furthermore, the knockdown of KCNQ1OT1 augmented the TMZ-induced tumor regression in TMZ-resistant U251 mouse models. Briefly, the present study evaluated that KCNQ1OT1 conferred TMZ resistance by releasing PIM1 expression from miR-761, resulting in the upregulation of PIM-mediated MDR1, c-Myc, and Survivin. The present findings demonstrated that the interplay of KCNQ1OT1: miR-761: PIM1 regulated chemoresistance in gliomas and provided a promising therapeutic target for TMZ-resistant glioma patients.

Knockdown of KCNQ1OT1 Inhibits Proliferation, Invasion, and Drug Resistance by Regulating miR-129-5p-Mediated LARP1 in Osteosarcoma

KCNQ1OT1 exerts an important role in various cancers, but its role in osteosarcoma (OS) and the potential mechanism remain to be clarified. In the present research, we aimed to explore the effect of KCNQ1OT1 on osteosarcoma and further explore the special molecular mechanism. The expression of KCNQ1OT1 was analyzed in tumor and adjacent tissues of 30 patients with osteosarcoma by RT-PCR. Cell proliferation and invasion were explored using MTT and transwell assay, respectively. Luciferase reporter analysis and pull-down assay were performed to determine the binding activity of KCNQ1OT1 and miR-129-5p. The result revealed that KCNQ1OT1 was highly expressed in osteosarcoma tissues and cells. KCNQ1OT1-siRNA inhibited the proliferation, invasion, and drug resistance of osteosarcoma cells. The luciferase reporter assay and pull-down assay demonstrated that KCNQ1OT1 directly interact with miR-129-5p. In addition, miR-129-5p binds to LARP1 directly, and LARP1 promoted the proliferation, invasion, and drug resistance of osteosarcoma cells. What is more, KCNQ1OT1 promoted proliferation, invasion, and drug resistance via inhibiting the expression of miR-129-5p and further promoting the expression of miR-129-5p-mediated LARP1. Collectively, it suggests that downregulation of KCNQ1OT1 inhibits proliferation, invasion, and drug resistance by regulating miR-129-5p-mediated LARP1 in osteosarcoma cells.

The functional role of long non-coding RNAs and their underlying mechanisms in drug resistance of non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is the most commonly diagnosed solid cancer and the main origin of cancer-related deaths worldwide. Current strategies to treat advanced NSCLC are based on a combined approach of targeted therapy and chemotherapy. But most patients will eventually get resistance to either chemotherapy or targeted therapy, leading to the poor prognosis. The mechanism of NSCLC drug resistance is inconclusive and is affected by multiple factors. Long non-coding RNAs (LncRNAs) are non-coding RNAs (ncRNAs) longer than 200 nucleotides. Recent studies show that lncRNAs are involved in many cellular physiological activities, including drug resistance of NSCLC. It is of great clinical significance to understand the specific mechanisms and the role of lncRNAs in it.

CONCLUSIONS

Herein, we focus on the functional roles and the underlying mechanisms of lncRNAs in acquired drug resistance of NSCLC. LncRNAs have potential values as novel prognostic biomarkers and even therapeutic targets in the clinical management of NSCLC.

Mechanisms of drug resistance mediated by long non-coding RNAs in non-small-cell lung cancer

Non-small-cell lung cancer (NSCLC) is the most prevalent form of lung cancer and has a poor five-year survival rate of 15%. Chemotherapy and targeted therapies have significantly improved patients' prognosis. Nevertheless, after a successful initial response, some patients relapse when cancer cells become resistant to drug treatments, representing an important clinical limitation. Therefore, investigating the mechanisms of drug resistance is of significant importance. Recently, considerable attention has been given to long non-coding RNAs (lncRNAs), a heterogeneous class of regulatory molecules that play essential roles in tumorigenesis by modulating genes and signalling pathways involved in cell growth, metastasis and drug response. In this article, we review recent research findings on the role of lncRNAs in drug resistance in NSCLC, highlighting their mechanisms of action.

KCNQ1OT1 contributes to sorafenib resistance and programmed death‑ligand‑1‑mediated immune escape via sponging miR‑506 in hepatocellular carcinoma cells

Drug resistance and immune escape of tumor cells severely compromise the treatment efficiency of hepatocellular carcinoma (HCC). Long non-coding RNA KCNQ1 overlapping transcript 1 (lncRNA KCNQ1OT1) has been shown to be involved in drug resistance in several cancers. The aim of the present study was to investigate the role of KCNQ1OT1 in sorafenib resistance and immune escape of HCC cells. Reverse transcription-quantitative PCR analysis, western blotting and immunohistochemistry were performed to detect the expression of KCNQ1OT1, miR-506 and programmed death-ligand-1 (PD-L1). Cell Counting Kit-8 assay, flow cytometry and Transwell assays were used to evaluate IC₅₀ value, cell apoptosis and metastasis. ELISA was performed to detect the secretion of cytokines. Dual-luciferase reporter assay was conducted to verify the targeting relationships between miR-506 and KCNQ1OT1 or PD-L1. KCNQ1OT1 and PD-L1 were found to be upregulated and miR-506 was downregulated in sorafenib-resistant HCC tissues and cells. Furthermore, KCNQ1OT1 knockdown reduced the IC₅₀ value of sorafenib, suppressed cell metastasis and promoted apoptosis in sorafenib-resistant HCC cells. Moreover, KCNQ1OT1 knockdown changed the tumor microenvironment and T-cell apoptosis in a sorafenib-resistant HCC/T-cell co-culture model. In addition, it was demonstrated that KCNQ1OT1 functioned as a competing endogenous RNA of miR-506 and increased PD-L1 expression in sorafenib-resistant HCC cells. miR-506 inhibition abolished the effects of KCNQ1OT1 knockdown on sorafenib sensitivity, tumor growth, the tumor microenvironment and T-cell apoptosis. In conclusion, KCNQ1OT1 knockdown inhibited sorafenib resistance and PD-L1-mediated immune escape by sponging miR-506 in sorafenib-resistant HCC cells.

Remodeling of Kv7.1 and Kv7.5 Expression in Vascular Tumors

Voltage-dependent potassium (Kv) channels contribute to the excitability of nerves and muscles. In addition, Kv participates in several cell functions, including cell cycle progression and proliferation. Kv channel remodeling has been associated with neoplastic cell growth and cancer. Kv7 channels are expressed in blood vessels, and they participate in the maintenance of vascular tone and are implicated in myocyte proliferation. Although evidence links Kv7 remodeling to different types of cancer, its expression in vascular tumors has never been studied. Endothelium-derived vascular neoplasms range from indolent lesions to highly aggressive and metastasizing cancers. Here, we show that Kv7.1 and Kv7.5 are evenly distributed in tunicas as well as the endothelium of healthy veins and arteries. The layered structure of vessels is lost in vascular tumors. By studying eight vascular tumors with different origins and characteristics, we found that Kv7.1 and Kv7.5 expression was changed in vascular cancers. While both channels were generally downregulated, Kv7.5 expression was clearly correlated with neoplastic malignancy. The vascular tumors did not contract; therefore, the role of Kv7 channels is probably related to proliferation rather than controlling vascular tone. Our results identify vascular Kv7 channels as targets for cancer detection and anticancer therapies.

Role of DNA Methylation in the Resistance to Therapy in Solid Tumors

Despite the recent advances in chemotherapeutic treatments against cancer, some types of highly aggressive and invasive cancer develop drug resistance against conventional therapies, which continues to be a major problem in the fight against cancer. In recent years, studies of alterations of DNA methylome have given us a better understanding of the role of DNA methylation in the development of tumors. DNA methylation (DNAm) is an epigenetic change that promotes the covalent transfer of methyl groups to DNA. This process suppresses gene expression through the modulation of the transcription machinery access to the chromatin or through the recruitment of methyl binding proteins. DNAm is regulated mainly by DNA methyltransferases. Aberrant DNAm contributes to tumor progression, metastasis, and resistance to current anti-tumoral therapies. Aberrant DNAm may occur through hypermethylation in the promoter regions of tumor suppressor genes, which leads to their silencing, while hypomethylation in the promoter regions of oncogenes can activate them. In this review, we discuss the impact of dysregulated methylation in certain genes, which impact signaling pathways associated with apoptosis avoidance, metastasis, and resistance to therapy. The analysis of methylome has revealed patterns of global methylation, which regulate important signaling pathways involved in therapy resistance in different cancer types, such as breast, colon, and lung cancer, among other solid tumors. This analysis has provided gene-expression signatures of methylated region-specific DNA that can be used to predict the treatment outcome in response to anti-cancer therapy. Additionally, changes in cancer methylome have been associated with the acquisition of drug resistance. We also review treatments with demethylating agents that, in combination with standard therapies, seem to be encouraging, as tumors that are in early stages can be successfully treated. On the other hand, tumors that are in advanced stages can be treated with these combination schemes, which could sensitize tumor cells that are resistant to the therapy. We propose that rational strategies, which combine specific demethylating agents with conventional treatment, may improve overall survival in cancer patients.

LncRNA KCNQ1OT1 is a key factor in the reversal effect of curcumin on cisplatin resistance in the colorectal cancer cells

The development of cisplatin resistance is a common cause of cancer recurrence in colorectal cancer (CRC). Though many studies have reported the oncogenic function of long non-coding RNA (LncRNA) KCNQ1OT1 in multiple cancers, few studies explored its role in cisplatin resistance of CRC. Curcumin is a natural phenolic compound extracted from turmeric, which can effectively suppress cisplatin resistance in CRC. This study aims to expound the role of KCNQ1OT1 in cisplatin resistance in CRC cells and whether KCNQ1OT1 participates in the reversal effect of curcumin on cisplatin resistance in CRC. The interplay between KCNQ1OT1 and miR-497 was determined using RNA pull-down assay and dual-luciferase reporter gene assay. The combination of B-cell lymphoma 2 (Bcl-2) and miR-497 was confirmed using dual-luciferase reporter gene assay. Compared with CRC cell line HCT8, the cisplatin-resistant CRC cell line HCT8/DDP exhibited a higher expression level of KCNQ1OT1. Functionally, the silence of KCNQ1OT1 suppressed proliferation and boosted apoptosis in HCT8/DDP cells. Subsequently, we found that KCNQ1OT1 could act as a sponge of miR-497 and remove the suppressive effect of miR-497 on Bcl-2 expression. Curcumin treatment restrained proliferation and facilitated apoptosis in HCT8/DDP cells. While KCNQ1OT1 overexpression removed the effect of curcumin on HCT8/DDP cells via miR-497/ Bcl-2 axis. Finally, the in vivo experiments showed that the inhibitory effect of curcumin on the growth of cisplatin-resistant CRC cells was reserved by the ectopic expression of KCNQ1OT1. In conclusion, KCNQ1OT1 aggravated cisplatin resistance in CRC cells via the miR-497/Bcl-2 axis. Administration of curcumin could effectively downregulate KCNQ1OT1 expression, thus reversing cisplatin resistance in CRC cells.

Emerging role of long non-coding RNAs in cancer chemoresistance: unravelling the multifaceted role and prospective therapeutic targeting

Chemotherapy is one of the important treatment modules in early as well as advanced stages of cancer. However, the major limitation of chemotherapy is the development of chemoresistance in the transformed cells of cancer patients, which leads to cancer recurrence. Long non-coding RNAs (lncRNA) are the transcripts longer than 200 nucleotides in length, which are reported to associate with the initiation, progression, recurrence, and metastasis of different cancers. Several lncRNAs have been implicated in the prevalence of chemoresistant phenotypes and also in the restoration of drug sensitivity in chemoresistant cells. LncRNAs such as HOTAIR, H19, and a lot more are involved in the chemoresistance of cancer cells. Therefore, targeting the lncRNAs may serve as a novel strategy for treating chemoresistant cancer. This review throws light on the role of lncRNA in chemoresistance along with the perspective of the therapeutic targets for the treatment of multiple cancers.

Long noncoding RNA KCNQ1OT1 is correlated with human breast cancer cell development through inverse regulation of hsa-miR-107

In this work, we investigated the expression pattern and regulatory function of long noncoding RNA (lncRNA) KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in breast cancer. We found that KCNQ1OT1 was significantly upregulated in breast cancer cell lines. In lentiviral-transduced BT-549 and HCC1599 cells, KCNQ1OT1 knockdown impaired cancer cell functions, including in vitro proliferation and migration, and in vivo transplant growth. The possible sponging target of KCNQ1OT1, human microRNA-107 (hsa-miR-107), was confirmed to be bound by KCNQ1OT1, and was upregulated in breast cancer cells with KCNQ1OT1 downregulation. Further, hsa-miR-107 knockdown in KCNQ1OT1-downregulated cancer cells reversed its impairing effects on cancer cell proliferation and migration in vitro. Thus, loss of KCNQ1OT1 is associated with functional impairment in breast cancer cells, likely through inverse regulation of its sponging target, hsa-miR-107.

Shikonin suppresses NEAT1 and Akt signaling in treating paclitaxel-resistant non-small cell of lung cancer

Background

The development of paclitaxel-resistance led to the tumor relapse and treatment failure of non-small cell lung cancer. Shikonin has been demonstrated to show anti-cancer activity in many cancer types. The present study aimed to investigate the anti-cancer activity of shikonin in paclitaxel-resistant non-small cell lung cancer treatment.

Methods

MTT, clonogenic assay, apoptotic cell death analysis, western blot, qRT-PCR, gene knockdown and overexpression, xenograft experiment, immunohistochemistry were performed.

Results

Shikonin decreased paclitaxel-resistant NSCLC cell viability and inhibited the growth of xenograft tumor. Shikonin induced apoptotic cell death of paclitaxel-resistant NSCLC cell lines and suppressed the level of NEAT1 and Akt signaling of paclitaxel-resistant NSCLC cell lines and xenograft tumors. Either low dose or high dose of shikonin considerably suppressed the cell growth and induced the cell apoptotic death in NEAT1 knockdown A549/PTX cells, and p-Akt expression was decreased.

Conclusions

Shikonin could be a promising candidate for paclitaxel-resistant NSCLC treatment.

Long non-coding RNAs regulate drug resistance in cancer

Chemoresistance, whether intrinsic or acquired, is a major obstacle in the treatment of cancer. The resistance of cancer cells to chemotherapeutic drugs can result from various mechanisms. Over the last decade, it has been reported that 1ong noncoding RNAs (lncRNAs) can mediate carcinogenesis and drug resistance/sensitivity in cancer cells. This article reviews, in detail, recent studies regarding the roles of lncRNAs in mediating drug resistance.

Long non-coding RNAs regulate drug resistance in cancer

Chemoresistance, whether intrinsic or acquired, is a major obstacle in the treatment of cancer. The resistance of cancer cells to chemotherapeutic drugs can result from various mechanisms. Over the last decade, it has been reported that 1ong noncoding RNAs (lncRNAs) can mediate carcinogenesis and drug resistance/sensitivity in cancer cells. This article reviews, in detail, recent studies regarding the roles of lncRNAs in mediating drug resistance.

Integrative Clustering Reveals a Novel Subtype of Soft Tissue Sarcoma With Poor Prognosis

Background

Soft tissue sarcomas (STSs) are heterogeneous at the clinical and molecular level and need to be further sub-clustered for treatment and prognosis.

Materials And Methods

STSs were sub-clustered based on RNAseq and miRNAseq data extracted from The Cancer Genome Atlas (TCGA) through the combined process of similarity network fusion (SNF) and consensus clustering (CC). The expression and clinical characteristics of each sub-cluster were analyzed. The genes differentially expressed (lncRNAs, miRNAs, and mRNAs) between the poor prognosis and good prognosis clusters were used to construct a competing endogenous RNA (ceRNA) network. Functional enrichment analysis was conducted and a hub network was extracted from the constructed ceRNA network.

Results

A total of 247 STSs were classified into three optimal sub-clusters, and patients in cluster 2 (C2) had a significantly lower rate of survival. A ceRNA network with 91 nodes and 167 edges was constructed according to the hypothesis of ceRNA. Functional enrichment analysis revealed that the network was mainly associated with organism development functions. Moreover, LncRNA (KCNQ1OT1)-miRNA (has-miR-29c-3p)-mRNA (JARID2, CDK8, DNMT3A, TET1)-competing endogenous gene pairs were identified as hub networks of the ceRNA network, in which each component showed survival significance.

Conclusion

Integrative clustering analysis revealed that the STSs could be clustered into three sub-clusters. The ceRNA network, especially the subnetwork LncRNA (KCNQ1OT1)-miRNA (has-miR-29c-3p)-mRNA (JARID2, CDK8, DNMT3A, TET1) was a promising therapeutic target for the STS sub-cluster associated with a poor prognosis.

Non-coding RNAs in Lung Cancer Chemoresistance

Background:

Lung cancer is the leading cause of cancer-associated death worldwide with limited treatment options. The major available treatment options are surgery, radiotherapy, chemotherapy and combinations of these treatments. In chemotherapy, tyrosine kinase inhibitors and taxol are the first lines of chemotherapeutics used for the treatment of lung cancer. Often drug resistance in the clinical settings hinders the efficiency of the treatment and intrigues the tumor relapse. Drug-resistance is triggered either by intrinsic factors or due to the prolonged cycles of chemotherapy as an acquired-resistance. There is an emerging role of non-coding RNAs (ncRNAs), including notorious microRNAs (miRNAs), proposed to be actively involved in the regulations of various tumor-suppressor genes and oncogenes.

Result:

The altered gene expression by miRNA is largely mediated either by the degradation or by interfering with the translation of targeted mRNA. Unlike miRNA, other type of ncRNAs, such as long non-coding RNAs (lncRNAs), can target the transcriptional activator or the repressor, RNA polymerase, and even DNA-duplex to regulate the gene expressions. Many studies have confirmed the crucial role of ncRNAs in lung adenocarcinoma progression and importantly, in the acquisition of chemoresistance. Recently, ncRNAs have become early biomarkers and therapeutic targets for lung cancer.

Conclusion:

Targeting ncRNAs could be an effective approach for the development of novel therapeutics against lung cancer and to overcome the chemoresistance.

LncRNA KCNQ1OT1 regulates microRNA-9-LMX1A expression and inhibits gastric cancer cell progression

LMX1A (LIM homeobox transcription factor 1α) is a tumor suppressor protein. Our previous study has shown that microRNA-9 (“miR-9”), being upregulated in human gastric cancer (GC), targets LMX1A to promote GC cell progression. Through searching long non-coding RNA (LncRNA) database, we identified that LncRNA KCNQ1OT1 is the competing endogenous RNA (ceRNA) of miR-9. KCNQ1OT1 putatively targets miR-9. Its level is downregulated in human GC tissues. In AGS cells and primary human GC cells, forced overexpression of KCNQ1OT1, by a lentiviral construct, induced miR-9 downregulation and LMX1A upregulation. Furthermore, KCNQ1OT1 overexpression inhibited GC cell survival, proliferation, migration and invasion, but inducing apoptosis activation. Contrarily, KCNQ1OT1 silencing, by targeted siRNAs, induced miR-9 accumulation and LMX1A downregulation. Consequently, GC cell proliferation, migration and invasion were enhanced. Importantly, KCNQ1OT1 overexpression or silencing was ineffective in LMX1A knockout AGC cells. Taken together, KCNQ1OT1 inhibits GC cell progression via regulating miR-9 and LMX1A expression.

Long Non-Coding RNA in Drug Resistance of Non-Small Cell Lung Cancer: A Mini Review

Lung cancer is one of main causes of cancer mortality and 83% of lung cancer cases are classified as non-small cell lung cancer (NSCLC). Patients with NSCLC usually have a poor prognosis and one of the leading causes is drug resistance. With the progress of drug therapy, the emergence and development of drug resistance affected the prognosis of patients severely. Accumulating evidence reveals that long non-coding RNAs (lncRNAs), as “dark matters” of the human genome, is of great significance to drug resistance in NSCLC. Herein, we review the role of lncRNAs in drug resistance in NSCLC.

Long Non-coding RNA KCNQ1OT1 Contributes to Antiepileptic Drug Resistance Through the miR-138-5p/ABCB1 Axis in vitro

Compelling evidence has verified that long non-coding RNAs (lncRNAs) play a critical role on drug resistance in various diseases, especially cancer. However, the role of lncRNAs underlying multidrug resistance in epilepsy remains to be clarified. In the present study, we investigated the potential regulatory mechanism of the lncRNA KCNQ1OT1 in regulating antiepileptic drug (AED) resistance in human brain microvascular endothelial cells (HBMECs). The results revealed that expression of P-glycoprotein (P-gp) and KCNQ1OT1 was significantly elevated in phenytoin-resistant HBMECs (HBMEC/PHT). Meanwhile, the activity of nuclear factor-kappa B (NF-κB) was increased in HBMECs/PHT cells. Microarray analysis indicated that miR-138-5p was downregulated in HBMEC/PHT cells. Interestingly, bioinformatics prediction tools indicated miR-138-5p could directly target the transcripts of KCNQ1OT1 and NF-κB p65, and these results were confirmed by luciferase assays. Moreover, KCNQ1OT1 downregulation or miR-138-5p upregulation in vitro could inhibit P-gp expression and suppress NF-κB signaling pathway activation. Additionally, knockdown of KCNQ1OT1 or overexpression of miR-138-5p could increase the accumulation of rhodamine 123 (Rh123) and AEDs in HBMEC/PHT cells. Collectively, our results suggested that KCNQ1OT1 contributes to AED resistance through the miR-138-5p/NF-κB/ABCB1 axis in HBMEC/PHT cells, and these results provide a promising therapeutic target for the treatment of medically intractable epilepsy.

LncRNA KCNQ1OT1 contributes to oxygen-glucose-deprivation/reoxygenation-induced injury via sponging miR-9 in cultured neurons to regulate MMP8

Our study proposed to investigate the function of potassium voltage-gated channel sub-family Q member 1 opposite strand 1 (KCNQ1OT1) in cerebral ischemia-reperfusion (I/R) injury and the underlying mechanism. We constructed an oxygen-glucose-deprivation/reoxygenation (OGD/R) model using the primary cortical neurons to mimic the cerebral I/R injury in vitro. Small inference RNA (siRNA) was used to silencing KCNQ1OT1. Dual luciferase assay was conducted to verify the interaction between KCNQ1OT1 and miR-9 and interaction between miR-9 and MMP8. CCK8 assay and flow cytometry analysis were applied for determing the viability and apoptosis of neurons, accordingly. QPCR and Western blot were performed to determine the RNA and protein expression. Our outcomes revealed that the expression of KCNQ1OT1 in cultured neurons was notably enhanced after suffered to OGD/R. Knockdown of KCNQ1OT1 weakened OGD/R-induced injury in neurons. Moreover, depletion of KCNQ1OT1 lead to the up-regulation of miR-9 and down-regulation of MMP8. Dual luciferase target validation assays demonstrated that KCNQ1OT1 directly interact with miR-9 and MMP8 is a direct target of miR-9, suggesting that KCNQ1OT1/miR-9/MMP8 might constitute the competing endogenous RNA (ceRNA) mechanism. Knockdown of MMP8 or up-regulation of miR-9 also could weaken OGD/R-induced injury. Furthermore, cells co-transfected with si-KCNQ1OT1, miR-9 mimic and si-MMP8 could significantly abolish the injury on neurons caused by OGD/R. Taken together, our data manifested that KCNQ1OT1 possibly acts as a facilitator in cerebral I/R injury through modulating miR-9/MMP8 axis as a ceRNA.

LncRNA KCNQ1OT1 contributes to the progression and chemoresistance in acute myeloid leukemia by modulating Tspan3 through suppressing miR-193a-3p

AIMS

Acute myeloid leukemia (AML) is an aggressive cancer that invariably produces drug resistance after treatment. The aim is to explore the role of lncRNA potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1 (KCNQ1OT1) and associated novel mechanisms in the progression and chemoresistance of AML.

MAIN METHODS

The expression of KCNQ1OT1, miR-193a-3p, and Tspan3 was measured by qRT-PCR. The values of IC50 for adriamycin (ADR) and the ability of proliferation were analyzed by CCK-8 assay. Cell migration and invasion were assessed by transwell assay. Cell apoptosis was monitored by flow cytometry assay. The expression of Tspan3, MRP1, P-gp and LRP at the protein level was quantified by western blot. The relationship between miR-193a-3p and KCNQ1OT1 or Tspan3 was predicted by bioinformatics tool Diana and verified by dual-luciferase reporter assay, RIP assay or RNA pull-down assay.

KEY FINDINGS

KCNQ1OT1 and Tspan3 were up-regulated, while miR-193a-3p was down-regulated in ADR resistant AML samples and cells. KCNQ1OT1 knockdown reduced ADR resistance, inhibited proliferation, migration and invasion but promoted apoptosis of ADR resistant AML cells, miR-193a-3p inhibition reversed these effects. MiR-193a-3p was a target of KCNQ1OT1 and combined with Tspan3 3' untranslated region (3' UTR). Enrichment of miR-193a-3p decreased ADR resistance, inhibited proliferation, migration and invasion and stimulated apoptosis in ADR resistant AML cells, but Tspan3 overexpression overturned these impacts.

SIGNIFICANCE

KCNQ1OT1 aggravates AML progression and chemoresistance to ADR by inducing Tspan3 expression via adsorbing miR-193a-3p in ADR resistant AML cells, providing a theoretical basis for the treatment of AML with chemoresistance.

Kcnq1ot1/miR-381-3p/ETS2 Axis Regulates Inflammation in Mouse Models of Acute Respiratory Distress Syndrome

Inflammatory mediators play a key role in the pathogenesis of acute respiratory distress syndrome (ARDS). In this study, we aimed to explore the involvement of the Kcnq1 opposite strand/antisense transcript 1 (Kcnq1ot1)/miR-381-3p/E26 transformation-specific proto-oncogene 2 (ETS2) axis in inflammation of lipopolysaccharide (LPS)-induced ARDS. Microarray analysis revealed ETS2 as an upregulated gene in ARDS. Then, a LPS-induced ARDS mouse model was constructed, with a series of gain- or loss-of-function experiments conducted to evaluate the lung function and neutrophil extracellular trap (NET) formation in lung tissue and determine the neutrophil number, myeloperoxidase (MPO) activity, and inflammatory factor levels in bronchoalveolar lavage fluid (BALF). As the results revealed, downregulated expression of ETS2 resulted in improved lung function, decreased NETs, MPO activity, and levels of interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α), as well as increased IL-10 level. Then, the assays of dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP), and RNA pull-down were performed to validate that Kcnq1ot1 promoted ETS2 expression by competitively binding to miR-381-3p. Meanwhile, it was also found that Kcnq1ot1 silencing reversed the promotive effect of EST2 on ARDS. Our results provide evidence that Kcnq1ot1 silencing may reduce the inflammatory response in LPS-induced ARDS via inhibition of miR-381-30-dependent ETS2, thereby presenting new molecular understanding for the development of ARDS.

Recent Progress in Characterizing Long Noncoding RNAs in Cancer Drug Resistance

Drug resistance is an important cause of failure in cancer chemotherapies. A large number of long noncoding RNAs (lncRNAs) have been found to be related to drug resistance in cancers. Therefore, lncRNAs provide potential targets for cancer therapies. The lncRNAs involved in cancer drug resistance are attracting interest from an increasing number of researchers. This review summarizes the latest research on the mechanisms and functions of lncRNAs in cancer drug resistance and envisages their future developments and therapeutic applications. This research suggests that lncRNAs regulate drug resistance through multiple mechanisms. LncRNAs do not affect drug resistance directly; usually, they do so by regulating the expression of some intermediate regulatory factors. In addition, lncRNAs exhibit a diversity of functions in cancer drug resistance. The overexpression of most lncRNAs promotes drug resistance, while a few lncRNAs have inhibitory effects.