Long noncoding RNA GAS5 inhibits malignant proliferation and chemotherapy resistance to doxorubicin in bladder transitional cell carcinoma

Long non-coding RNA (lncRNA) PVT1 in drug resistance of cancers: Focus on pathological mechanisms

According to estimates, cancer will be the leading cause of death globally in 2022, accounting for 9.6 million deaths. At present, the three main therapeutic modalities utilized to treat cancer are radiation therapy, chemotherapy, and surgery. However, during treatment, tumor cells resistant to chemotherapy may arise. Drug resistance remains a major oppose since it often leads to therapeutic failure. Furthermore, the term "acquired drug resistance" describes the situation where tumor cells already display drug resistance before undergoing chemotherapy. However, little is still known about the basic mechanisms underlying chemotherapy-induced drug resistance. The development of new technologies and bioinformatics has led to the discovery of additional genes associated with drug resistance. Long noncoding RNA plasmacytoma variant translocation 1 (PVT1) has been linked to an increased risk of cancer, according to a growing body of research. Apart from biological functions associated with cell division, development, pluripotency, and cell cycle, lncRNA PVT1 contributes significantly to the regulation of various aspects of genome function, such as transcription, splicing, and epigenetics. The article will address the mechanism by which lncRNA PVT1 influences drug resistance in cancer cells.

Insights into the involvement of long non-coding RNAs in doxorubicin resistance of cancer

Doxorubicin is one of the most classical chemotherapeutic drugs for the treatment of cancer. However, resistance to the cytotoxic effects of doxorubicin in tumor cells remains a major obstacle. Aberrant expression of long non-coding RNAs (lncRNAs) has been associated with tumorigenesis and development via regulation of chromatin remodeling, transcription, and post-transcriptional processing. Emerging studies have also revealed that dysregulation of lncRNAs mediates the development of drug resistance through multiple molecules and pathways. In this review, we focus on the role and mechanism of lncRNAs in the progress of doxorubicin resistance in various cancers, which mainly include cellular drug transport, cell cycle disorder, anti-apoptosis, epithelial-mesenchymal transition, cancer stem cells, autophagy, tumor microenvironment, metabolic reprogramming and signaling pathways. This review is aimed to provide potential therapeutic targets for future cancer therapy, especially for the reversal of chemoresistance.

Molecular landscape of LncRNAs in bladder cancer: From drug resistance to novel LncRNA-based therapeutic strategies

Bladder cancer (BC) is a common and serious type of cancer that ranks among the top ten most prevalent malignancies worldwide. Due to the high occurrence rate of BC, the aggressive nature of cancer cells, and their resistance to medication, managing this disease has become a growing challenge in clinical care. Long noncoding RNAs (lncRNAs) are a group of RNA transcripts that do not code for proteins and are more than 200 nucleotides in length. They play a significant role in controlling cellular pathways and molecular interactions during the onset, development and progression of different types of cancers. Recent advancements in high-throughput gene sequencing technology have led to the identification of various differentially expressed lncRNAs in BC, which indicate abnormal expression. In this review, we summarize that these lncRNAs have been found to impact several functions related to the development of BC, including proliferation, cell growth, migration, metastasis, apoptosis, epithelial-mesenchymal transition, and chemo- and radio-resistance. Additionally, lncRNAs may improve prognosis prediction for BC patients, indicating a future use for them as prognostic and diagnostic biomarkers for BC patients. This review highlights that genetic tools and anti-tumor agents, such as CRISPR/Cas systems, siRNA, shRNA, antisense oligonucleotides, and vectors, have been created for use in preclinical cancer models. This has led to a growing interest in using lncRNAs based on positive research findings.

Noncoding RNAs as a potential biomarker for the prognosis of bladder cancer: a systematic review and meta-analysis

OBJECTIVE

The relationship between noncoding RNAs and the prognosis of bladder cancer (BC) is still controversial. The purpose of this study is to evaluate the relationship between noncoding RNAs and prognosis by meta-analysis.

METHODS

Comprehensive retrieval of PubMed, Embase, the Cochrane Library, the Web of Science, CNKI, and WanFang databases is related to the correlation between noncoding RNAs and the prognosis of BC. Data were extracted, and the literature quality was evaluated. STATA16.0 served for the meta-analysis.

RESULTS

1. CircRNAs: High circ-ZFR expression led to poor overall survival (OS) of BC. 2. LncRNAs: Low lnc-GAS5 expression predicted poor OS of BC, high lnc-TUG1 expression predicted poor OS of BC. 3. MiRNAs: High miR-21 expression predicted poor OS of BC, high miR-222 expression led to poor OS of BC, high miR-155 expression predicted poor progression-free survival (PFS) of BC, high miR-143 expression caused poor PFS of BC, low miR-214 expression could result in poor recurrence-free survival (RFS) of BC.

CONCLUSIONS

High circ-ZFR, lnc-TUG1, miR-222, and miR-21 expressions were correlated with poor OS of BC; high miR-155 and miR-143 expression predicted poor PFS of BC; low lnc-GAS5 expression predicted poor OS of BC; low miR-214 expression predicted poor RFS of BC.

The Diagnostic and Therapeutic Role of snoRNA and lincRNA in Bladder Cancer

Bladder cancer is one of the most common malignancies of the urinary tract and can be divided into non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). Although the means of diagnosis and treatment have continually improved in recent years, the recurrence rate of bladder cancer remains high, and patients with MIBC typically have an unfavourable prognosis and a low quality of life. Emerging evidence demonstrates that long noncoding RNAs play a crucial role in the carcinogenesis and progression of bladder cancer. Long intergenic noncoding RNAs (lincRNAs) are a subgroup of long noncoding RNAs (lncRNAs) that do not overlap protein-coding genes. The potential role of lincRNAs in the regulation of gene expression has been explored in depth in recent years. Small nucleolar RNAs (snoRNAs) are a class of noncoding RNAs (ncRNAs) that mainly exist in the nucleolus, are approximately 60-300 nucleotides in length, and are hosted inside the introns of genes. Small nucleolar RNA host genes (SNHGs) have been associated with the origin and development of bladder cancer. In this review, we aim to comprehensively summarize the biological functions of these molecules in bladder cancer.

Long Non-Coding RNA and Chemoresistance in Bladder Cancer - A Mini Review

Bladder cancer is the 10th most common cancer worldwide. It is a heterogeneous disease, comprising several tumor subtypes with differences in histology, genomic aberrations, prognosis and sensitivity to anti-cancer treatments. Although the treatment of bladder cancer is based tumor classifications and gradings, patients have different clinical response. In recent years, long non-coding RNAs (lncRNAs) were associated with bladder cancer chemoresistance. Thus, lncRNAs seem to be promising targets in treatment of bladder cancer. This review highlights the recent findings concerning lncRNAs and their relevance to the chemoresistance of bladder cancer. This may provide a basis for exploiting more robust therapeutic approaches in the future.

Synergistic effect of metformin and doxorubicin on the metastatic potential of T24 cells

BACKGROUND

The motor ability of cancer cells to cross the basement membrane contributes to their implantation in a new location. Metastasis is a significant factor that worsens the prognosis of cancer patients. Thus, reducing cell invasiveness is an important aspect of anticancer therapy, also in bladder cancer treatment.

MATERIAL

The study material was the T24 cell line of human urinary bladder cancer. The migratory potential of the cells and the effect of the treatment with individually doses and synergistic combination of doxorubicin and metformin in the 500:1 ratio for 24 h were analyzed.

RESULTS

The results obtained show a compound-initiated decrease in the motor abilities of bladder cancer cells compared to controls. A decrease in the rate of colony formation was observed, as well as inhibition of migration through inserts. The visualized reorganization of the vimentin and actin networks confirms the drug-initiated limitation of the metastatic potential of T24 cells.

CONCLUSION

According to our knowledge, we are the first to show, that combination of doxorubicin and metformin also worth considering in the treatment of bladder cancer. We showed that simultaneous administration of these cytostatic enhances the antiproliferative effect of drugs, but also limits cells' migratory potential.

Contribution of Non-Coding RNAs to Anticancer Effects of Dietary Polyphenols: Chlorogenic Acid, Curcumin, Epigallocatechin-3-Gallate, Genistein, Quercetin and Resveratrol

Growing evidence has been accumulated to show the anticancer effects of daily consumption of polyphenols. These dietary polyphenols include chlorogenic acid, curcumin, epigallocatechin-3-O-gallate, genistein, quercetin, and resveratrol. These polyphenols have similar chemical and biological properties in that they can act as antioxidants and exert the anticancer effects via cell signaling pathways involving their reactive oxygen species (ROS)-scavenging activity. These polyphenols may also act as pro-oxidants under certain conditions, especially at high concentrations. Epigenetic modifications, including dysregulation of noncoding RNAs (ncRNAs) such as microRNAs, long noncoding RNAs, and circular RNAs are now known to be involved in the anticancer effects of polyphenols. These polyphenols can modulate the expression/activity of the component molecules in ROS-scavenger-triggered anticancer pathways (RSTAPs) by increasing the expression of tumor-suppressive ncRNAs and decreasing the expression of oncogenic ncRNAs in general. Multiple ncRNAs are similarly modulated by multiple polyphenols. Many of the targets of ncRNAs affected by these polyphenols are components of RSTAPs. Therefore, ncRNA modulation may enhance the anticancer effects of polyphenols via RSTAPs in an additive or synergistic manner, although other mechanisms may be operating as well.

GAS5 alleviates cisplatin drug resistance in oral squamous cell carcinoma by sponging miR-196a

Objective

The long non-coding RNA Growth-arrest-specific transcript 5 (GAS5) has been extensively linked with the ability of cancer cells to resist chemotherapeutic interventions. This prospective study aimed to investigate the role of GAS5 in oral squamous cell carcinoma (OSCC), which has been poorly characterized to date.

Methods

GAS5 and miR-196a expression levels were detected by quantitative real-time PCR analysis. Cisplatin (DDP) sensitivity and apoptosis levels were determined using Cell Counting Kit 8 and flow cytometry, respectively. Luciferase reporter and RNA immunoprecipitation assays were performed to confirm target miRNAs of GAS5.

Results

We found that GAS5 was expressed at low levels in DDP-resistant OSCC cell lines and tissues, and that GAS5 levels were intricately linked to the survival rates of OSCC patients. GAS5 overexpression led to the recovery of DDP sensitivity in CAL27/DDP cells. Additionally, in both DDP-resistant and -sensitive lines, GAS5 showed a cytoplasmic distribution and downregulated miR-196a in OSCC tissues. Exogenous transfection of miR-196a alleviated the effects of GAS5 on DDP sensitivity, confirming this as the mechanism of chemoresistance.

Conclusions

These findings may provide new targets for the treatment of chemotherapy-resistant OSCC.

Emerging roles of long noncoding RNAs in chemoresistance of pancreatic cancer

Pancreatic cancer is one of the most common causes of cancer death in the world due to the lack of early symptoms, metastasis occurrence and chemoresistance. Therefore, early diagnosis by detection of biomarkers, blockade of metastasis, and overcoming chemoresistance are the effective strategies to improve the survival of pancreatic cancer patients. Accumulating evidence has revealed that long noncoding RNA (lncRNA) and circular RNAs (circRNAs) play essential roles in modulating chemosensitivity in pancreatic cancer. In this review article, we will summarize the role of lncRNAs in drug resistance of pancreatic cancer cells, including HOTTIP, HOTAIR, PVT1, linc-ROR, GAS5, UCA1, DYNC2H1-4, MEG3, TUG1, HOST2, HCP5, SLC7A11-AS1 and CASC2. We also highlight the function of circRNAs, such as circHIPK3 and circ_0000284, in regulation of drug sensitivity of pancreatic cancer cells. Moreover, we describe a number of compounds, including curcumin, genistein, resveratrol, quercetin, and salinomycin, which may modulate the expression of lncRNAs and enhance chemosensitivity in pancreatic cancers. Therefore, targeting specific lncRNAs and cicrRNAs could contribute to reverse chemoresistance of pancreatic cancer cells. We hope this review might stimulate the studies of lncRNAs and cicrRNAs, and develop the new therapeutic strategy via modulating these noncoding RNAs to promote chemosensitivity of pancreatic cancer cells.

Research Progress of Long Non-Coding RNA GAS5 in Malignant Tumors

With completing the whole genome sequencing project, awareness of lncRNA further deepened. The growth arrest-specific transcript 5 (GAS5) was initially identified in growth-inhibiting cells. GAS5 is a lncRNA (long non-coding RNA), and it plays a crucial role in various human cancers. There are small ORFs (open reading frames) in the exons of the GAS5 gene sequence, but they do not encode functional proteins. In addition, GAS5 is also the host gene of several small nucleolar RNAs (snoRNA). These snoRNAs are believed to play a suppressive role during tumor progression by methylating ribosomal RNA (rRNA). As a result, GAS5 expression levels in tumor tissues are significantly reduced, leading to increased malignancy, poor prognosis, and drug resistance. Recent studies have demonstrated that GAS5 can interact with miRNAs by base-pairing and other functional proteins to inhibit their biological functions, impacting signaling pathways and changing the level of intracellular autophagy, oxidative stress, and immune cell function in vivo. In addition, GAS5 participates in regulating proliferation, invasion, and apoptosis through the above molecular mechanisms. This article reviews the recent discoveries on GAS5, including its expression levels in different tumors, its biological behavior, and its molecular regulation mechanism in human cancers. The value of GAS5 as a molecular marker in the prevention and treatment of cancers is also discussed.

LncRNA polymorphisms and urologic cancer risk

Urologic cancers involve nearly one-quarter of all cancers and include the prostate, bladder, and kidney cancers. Long non-coding RNAs (LncRNAs) are expressed in a tissue-specific manner and affect cell proliferation, apoptosis, and differentiation. LncRNAs expression is misregulated in urologic cancers, as their aberrant expression may make them capable of being utilized in the diagnosis, prognosis, and treatment of cancers. LncRNAs polymorphisms can affect their structure, expression, and function by interfering with the associated target mRNAs. As a result, lncRNA polymorphisms may be linked to the mechanism driving cancer susceptibility. Therefore, SNPs in lncRNAs may be a beneficial biomarker for early diagnosis and prognosis of cancers, as they affect lncRNA role in tumorigenesis and cancer progression. Moreover, the genetic heredity of lncRNA SNPs affects the personal therapeutic response to drugs. In this study, the lncRNAs polymorphism is summarized in relation to urologic cancers. It is proposed that lncRNA-related polymorphisms, as an individual or combined genotypes, can predict urologic cancer risk, even clinical and prognostic outcomes. However, large-scale population-based prospective studies and comprehensive meta-analyses should be conducted to validate and use these lncRNAs SNPs as the indicators of urologic cancers. Future research should examine the function of these SNPs to explain their associations with urologic cancers.

LncRNA GAS5 rs145204276 Polymorphism Reduces Renal Cell Carcinoma Susceptibility in Southern Chinese Population

Objective

Methods

Results

Conclusions

Emerging strategies for the improvement of chemotherapy in bladder cancer: Current knowledge and future perspectives

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The response of chemotherapy and prognosis in bladder cancer is unsatisfied.

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Immunotherapy, targeted therapy, and ADC improve the efficacy of chemotherapy.

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Emerging targets in cancer cells and TME spawned novel preclinical agents.

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Novel drug delivery, such as nanotechnology, enhances effects of chemotherapeutics.

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The organoid and PDX model are promising to screen and evaluate the target therapy.

Background

Chemotherapy is a first-line treatment for advanced and metastatic bladder cancer, but the unsatisfactory objective response rate to this treatment yields poor 5-year patient survival. Only PD-1/PD-L1-based immune checkpoint inhibitors, FGFR3 inhibitors and antibody-drug conjugates are approved by the FDA to be used in bladder cancer, mainly for platinum-refractory or platinum-ineligible locally advanced or metastatic urothelial carcinoma. Emerging studies indicate that the combination of targeted therapy and chemotherapy shows better efficacy than targeted therapy or chemotherapy alone. Newly identified targets in cancer cells and various functions of the tumour microenvironment have spawned novel agents and regimens, which give impetus to sensitizing chemotherapy in the bladder cancer setting.

Aim of Review

This review aims to present the current evidence for potentiating the efficacy of chemotherapy in bladder cancer. We focus on combining chemotherapy with other treatments as follows: targeted therapy, including immunotherapy and antibody-drug conjugates in clinic; novel targeted drugs and nanoparticles in preclinical models and potential targets that may contribute to chemosensitivity in future clinical practice. The prospect of precision therapy is also discussed in bladder cancer.

Key Scientific Concepts of Review

Combining chemotherapy drugs with immune checkpoint inhibitors, antibody-drug conjugates and VEGF inhibitors potentially elevates the response rate and survival. Novel targets, including cancer stem cells, DNA damage repair, antiapoptosis, drug metabolism and the tumour microenvironment, contribute to chemosensitization. Gene alteration-based drug selection and patient-derived xenograft- and organoid-based drug validation are the future for precision therapy.

Biological functions and clinical significance of long noncoding RNAs in bladder cancer

Bladder cancer (BCa) is one of the 10 most common cancers with high morbidity and mortality worldwide. Long noncoding RNAs (lncRNAs), a large class of noncoding RNA transcripts, consist of more than 200 nucleotides and play a significant role in the regulation of molecular interactions and cellular pathways during the occurrence and development of various cancers. In recent years, with the rapid advancement of high-throughput gene sequencing technology, several differentially expressed lncRNAs have been discovered in BCa, and their functions have been proven to have an impact on BCa development, such as cell growth and proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and drug-resistance. Furthermore, evidence suggests that lncRNAs are significantly associated with BCa patients' clinicopathological characteristics, especially tumor grade, TNM stage, and clinical progression stage. In addition, lncRNAs have the potential to more accurately predict BCa patient prognosis, suggesting their potential as diagnostic and prognostic biomarkers for BCa patients in the future. In this review, we briefly summarize and discuss recent research progress on BCa-associated lncRNAs, while focusing on their biological functions and mechanisms, clinical significance, and targeted therapy in BCa oncogenesis and malignant progression.

MALAT-1 is Associated with the Doxorubicin Resistance in U-2OS Osteosarcoma Cells

Purpose

Our study aimed to investigate the relationship between MALAT-1 (metastasis-associated lung adenocarcinoma transcript 1) expression and the chemotherapy drug resistance in osteosarcoma.

Methods

The U-2OS osteosarcoma cell line was selected for the experiment. The cells were treated with methotrexate, doxorubicin, cisplatin, and ifosfamide, respectively. RT-PCR was applied to detect the MALAT-1 expression in cells. The doxorubicin-resistant cell line was constructed. The cells were divided into doxorubicin-sensitivity group (DS/shCtrl), doxorubicin-resistance group (DR/shCtrl) and shMALAT1-doxorubicin-resistance group (DR/shMALAT1). The colony formation assay and 5-ethynyl-2ʹ-deoxyuridine (EdU) assay were used to detect cell proliferation. PI staining was used to detect the cell cycle. Transwell assay and wound healing assay were used to observe the migration and invasion ability. Annexin V-FITC assay was used to detect cell apoptosis. Western blot was used to detect the protein expression and potential mechanism. The impacts of MALAT-1 expression were verified in vivo.

Results

The MALAT-1 was upregulated in the doxorubicin-resistant U-2OS osteosarcoma cells. Downregulating MALAT-1 in the doxorubicin-resistant cells inhibited the proliferation, migration, and invasiveness, increased the ratio of cells in the G0/G1 phase, promoted apoptosis. In the doxorubicin-resistant U-2OS cells, the extracellular regulated protein kinases (ERK) phosphorylation was declined, which could be reversed by downregulating MALAT-1. In vivo assay indicated that the growth of doxorubicin-resistant solid osteosarcoma could be suppressed by downregulating MALAT-1.

Conclusion

Our study provides evidence that doxorubicin may upregulate MALAT-1 in osteosarcoma. Downregulating MALAT-1 in the doxorubicin resistance U-2OS cells could reverse the resistance and may improve chemotherapeutic efficiency. Some conclusions in previous literature may be one-sided.

Long non-coding RNAs as the critical regulators of doxorubicin resistance in tumor cells

Resistance against conventional chemotherapeutic agents is one of the main reasons for tumor relapse and poor clinical outcomes in cancer patients. Various mechanisms are associated with drug resistance, including drug efflux, cell cycle, DNA repair and apoptosis. Doxorubicin (DOX) is a widely used first-line anti-cancer drug that functions as a DNA topoisomerase II inhibitor. However, DOX resistance has emerged as a large hurdle in efficient tumor therapy. Furthermore, despite its wide clinical application, DOX is a double-edged sword: it can damage normal tissues and affect the quality of patients’ lives during and after treatment. It is essential to clarify the molecular basis of DOX resistance to support the development of novel therapeutic modalities with fewer and/or lower-impact side effects in cancer patients. Long non-coding RNAs (lncRNAs) have critical roles in the drug resistance of various tumors. In this review, we summarize the state of knowledge on all the lncRNAs associated with DOX resistance. The majority are involved in promoting DOX resistance. This review paves the way to introducing an lncRNA panel marker for the prediction of the DOX response and clinical outcomes for cancer patients.

Circulating Long Non-Coding RNA GAS5: A Non-Invasive Molecular Marker for Prognosis, Response to Treatment and Survival in Non-Small Cell Lung Cancer

Circulating long non-coding RNAs (lncRNA) are dysregulated in several diseases, especially cancers, e.g. non-small-cell lung cancer (NSCLC). Of specific notice in this regard is growth arrest-specific 5 gene (lncRNA GAS5), which is principally recognised as a tumor suppressor gene in numerous cancers. Functionally, GAS5 is involved in arresting cellular growth and induction of apoptosis. We analysed plasma GAS5 expression by qRT-PCR in 100 patients with NSCLC before and after tumour resection surgery. We reported a downregulation of GAS5 expression in NSCLC tissue and plasma, which showed elevation after surgery. Downregulation of GAS5 was associated with poor prognosis of NSCLC patients.

Long Noncoding RNA Small Nucleolar Host Gene: A Potential Therapeutic Target in Urological Cancers

The incidence of urological cancer has been gradually increasing in the last few decades. However, current diagnostic tools and treatment strategies continue to have limitations. Substantial evidence shows that long noncoding RNAs (lncRNAs) play essential roles in carcinogenesis and the progression, treatment response and prognosis of multiple human cancers, including urological cancers, gastrointestinal tumours, reproductive cancers and respiratory neoplasms. LncRNA small nucleolar RNA host genes (SNHGs), a subgroup of lncRNAs, have been found to be dysregulated in tumour cell biology. In this review, we summarize the impacts of lncRNA SNHGs in urological malignancies and the underlying mechanisms.

The role of miRNAs and lncRNAs in conferring resistance to doxorubicin

Doxorubicin is a chemotherapeutic agent that inhibits topoisomerase II, intercalates within DNA base pairs and results in oxidative DNA damage, thus inducing cell apoptosis. Although it is effective in the treatment of a wide range of human cancers, the emergence of resistance to this drug can increase tumour growth and impact patients' survival. Numerous molecular mechanisms and signalling pathways have been identified that induce resistance to doxorubicin via stimulation of cell proliferation, cell cycle switch and preclusion of apoptosis. A number of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have also been identified that alter sensitivity to doxorubicin. Understanding the particular impact of these non-coding RNAs in conferring resistance to doxorubicin has considerable potential to improve selection of chemotherapeutic regimens for cancer patients. Moreover, modulation of expression of these transcripts is a putative strategy for combating resistance. In the current paper, the influence of miRNAs and lncRNAs in the modification of resistance to doxorubicin is discussed.

Knockdown of microRNA-130b improves doxorubicin sensitivity in bladder urothelial carcinoma by negatively regulating cylindromatosis expression

INTRODUCTION

Chemotherapeutic resistance reduces the sensitivity of bladder urothelial carcinoma (BUC) to chemotherapeutic drugs and contributes a barrier leading to treatment failure. The purpose of this research project is to investigate the regulatory effects of miR-130b on chemotherapeutic drug resistance of BUC and its mechanism.

MATERIAL AND METHODS

The relative expression of miRNA-130b and cylindromatosis (CYLD) was examined using real-time quantitative PCR. The cell proliferation and doxorubicin sensitivity were detected with the enhanced CCK-8 assay. The specific combination of miR-130b and CYLD was verified with the luciferase reporter gene assay. Protein expression was detected by Western blot.

RESULTS

Our study found that miR-130b was up-regulated in doxorubicin-insensitive BUC tissues and cell lines, and its high expression was negatively related to doxorubicin sensitivity in BUC. The miR-130b knockdown reduced the IC₅₀ of doxorubicin and improved doxorubicin sensitivity of J82/Dox and T24/Dox cells. For the regulation mechanism analysis of miR-130b, bioinformatics analysis software was used to predict the potential targets of miR-130b, including the CYLD gene. The following luciferase activities assay, quantitative real time-PCR and western blot identified the CYLD gene as a target of miR-130b. Knockdown of CYLD reversed miR-130b's regulatory roles in doxorubicin sensitivity in J82/Dox and T24/Dox cells.

CONCLUSIONS

High expression of miR-130b is negatively related to doxorubicin sensitivity in BUC, and knockdown of miR-130b improves doxorubicin sensitivity in BUC by negatively regulating CYLD expression. Our findings will provide guidance for the clinical chemotherapy of BUC.

Non-coding RNAs underlying chemoresistance in gastric cancer

BACKGROUND

Gastric cancer (GC) is a major health issue in the Western world. Current clinical imperatives for this disease include the identification of more effective biomarkers to detect GC at early stages and enhance the prevention and treatment of metastatic and chemoresistant GC. The advent of non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long-non coding RNAs (lncRNAs), has led to a better understanding of the mechanisms by which GC cells acquire features of therapy resistance. ncRNAs play critical roles in normal physiology, but their dysregulation has been detected in a variety of cancers, including GC. A subset of ncRNAs is GC-specific, implying their potential application as biomarkers and/or therapeutic targets. Hence, evaluating the specific functions of ncRNAs will help to expand novel treatment options for GC.

CONCLUSIONS

In this review, we summarize some of the well-known ncRNAs that play a role in the development and progression of GC. We also review the application of such ncRNAs in clinical diagnostics and trials as potential biomarkers. Obviously, a deeper understanding of the biology and function of ncRNAs underlying chemoresistance can broaden horizons toward the development of personalized therapy against GC.

Non coding RNAs as the critical factors in chemo resistance of bladder tumor cells

BACKGROUND

Bladder cancer (BCa) is the ninth frequent and 13th leading cause of cancer related deaths in the world which is mainly observed among men. There is a declining mortality rates in developed countries. Although, the majority of BCa patients present Non-Muscle-Invasive Bladder Cancer (NMIBC) tumors, only 30% of patients suffer from muscle invasion and distant metastases. Radical cystoprostatectomy, radiation, and chemotherapy have proven to be efficient in metastatic tumors. However, tumor relapse is observed in a noticeable ratio of patients following the chemotherapeutic treatment. Non-coding RNAs (ncRNAs) are important factors during tumor progression and chemo resistance which can be used as diagnostic and prognostic biomarkers of BCa.

MAIN BODY

In present review we summarized all of the lncRNAs and miRNAs associated with chemotherapeutic resistance in bladder tumor cells.

CONCLUSIONS

This review paves the way of introducing a prognostic panel of ncRNAs for the BCa patients which can be useful to select a proper drug based on the lncRNA profiles of patients to reduce the cytotoxic effects of chemotherapy in such patients.

The Non-Coding RNA GAS5 and Its Role in Tumor Therapy-Induced Resistance

The growth arrest-specific transcript 5 (GAS5) is a >200-nt lncRNA molecule that regulates several cellular functions, including proliferation, apoptosis, invasion and metastasis, across different types of human cancers. Here, we reviewed the current literature on the expression of GAS5 in leukemia, cervical, breast, ovarian, prostate, urinary bladder, lung, gastric, colorectal, liver, osteosarcoma and brain cancers, as well as its interaction with various miRNAs and its effect on therapy-related resistance in these malignancies. The general consensus is that GAS5 acts as a tumor suppressor across different tumor types and that its up-regulation results in tumor sensitization to chemotherapy or radiotherapy. GAS5 seems to play a previously unappreciated, but significant role in tumor therapy-induced resistance.

The role of long non-coding RNAs in drug resistance of cancer

Long non-coding RNAs (lncRNAs), a class of long RNAs, are longer than 200 nucleotides in length but lack protein-coding capacity. LncRNAs, as critical genomic regulators, are involved in genomic imprinting regulation, histone modification and gene expression regulation as well as tumor initiation and progression. However, it is also found that lncRNAs are associated with drug resistance in several types of cancer. Drug resistance is an important reason for clinical chemotherapy failure, and the molecular mechanism of tumor resistance is complex, which is a process of multi-cause, multi-gene and multi-signal transduction pathway interaction. Then comprehending the mechanisms of chemoresistance will help find ways to control the tumor progression effectively. Therefore, in this review, we will construct lncRNAs /drug resistance interaction network and shed light on the role of lncRNAs in drug resistance.

lncRNA and Mechanisms of Drug Resistance in Cancers of the Genitourinary System

Available systemic treatment options for cancers of the genitourinary system have experienced great progress in the last decade. However, a large proportion of patients eventually develop resistance to treatment, resulting in disease progression and shorter overall survival. Biomarkers indicating the increasing resistance to cancer therapies are yet to enter clinical routine. Long non-coding RNAs (lncRNA) are non-protein coding RNA transcripts longer than 200 nucleotides that exert multiple types of regulatory functions of all known cellular processes. Increasing evidence supports the role of lncRNAs in cancer development and progression. Additionally, their involvement in the development of drug resistance across various cancer entities, including genitourinary malignancies, are starting to be discovered. Consequently, lncRNAs have been suggested as factors in novel therapeutic strategies to overcome drug resistance in cancer. In this review, the existing evidences on lncRNAs and their involvement in mechanisms of drug resistance in cancers of the genitourinary system, including renal cell carcinoma, bladder cancer, prostate cancer, and testicular cancer, will be highlighted and discussed to facilitate and encourage further research in this field. We summarize a significant number of lncRNAs with proposed pathways in drug resistance and available reported studies.

Silence of FAM83H-AS1 promotes chemosensitivity of gastric cancer through Wnt/β-catenin signaling pathway

Gastric cancer (GC) is a malignant tumor originated from the epithelium of gastric mucosa, its incidence is second only to lung cancer in China. Chemotherapy is one of the most effective methods to treat GC, but some patients are insensitive to chemotherapeutic drugs, leading to chemotherapy failure. In this study, the expression of FAM83H-AS1 was up-regulated in GC tissues and cell lines, and was related to differentiation, invasion depth and chemotherapy insensitivity of GC patients. FAM83H-AS1 was high-expressed in chemoresistant GC tissues and cell line (SGC7901/R), and silence of FAM83H-AS1 sensitized SGC7901/R cells to cisplatin (CDDP) and 5-fluorouracil (5-FU). In addition, silence of FAM83H-AS1 could inactivate Wnt/β-catenin signaling pathway in SGC7901/R cells. The activating of Wnt/β-catenin signaling pathway reversed the promoting effect of FAM83H-AS1 silence on chemotherapy sensitivity, which meant Wnt/β-catenin signaling pathway mediated the regulation of FAM83H-AS1 on chemotherapy sensitivity in SGC7901/R cells. In conclusion, FAM83H-AS1 is related with the CDDP and 5-FU insensitivity of GC patients, silence of FAM83H-AS1 promotes chemosensitivity of GC through Wnt/β-catenin signaling pathway.

Long non-coding RNAs in genitourinary malignancies: a whole new world

Long non-coding RNAs (lncRNAs) are regulators of cellular machinery that are commonly dysregulated in genitourinary malignancies. Accordingly, the investigation of lncRNAs is improving our understanding of genitourinary cancers, from development to progression and dissemination. lncRNAs are involved in major oncogenic events in genitourinary malignancies, including androgen receptor (AR) signalling in prostate cancer, hypoxia-inducible factor (HIF) pathway activation in renal cell carcinoma and invasiveness in bladder cancer, as well as multiple other proliferation and survival mechanisms. In line with their putative oncogenic roles, new lncRNA-based classifications are emerging as potent predictors of prognosis. In clinical practice, detection of oncogenic lncRNAs in serum or urine might enable early cancer detection, and lncRNAs might also be promising therapeutic targets for patients with genitourinary cancer. Furthermore, as predictors of sensitivity to anticancer treatments, lncRNAs could be integrated into future precision medicine strategies. Overall, lncRNAs are promising new candidates for molecular studies and for discovery of innovative biomarkers and are putative therapeutic targets in genitourinary oncology.

LncRNAs act as prognostic biomarkers in bladder carcinoma: A meta-analysis

Background and purpose

Increasing studies have shown that different kinds of lncRNAs play key role in the development of multiple carcinomas. Therefore, we conducted a meta-analysis to investigate an association between the expression level of lncRNAs and the prognosis of bladder cancer (death or other clinical outcomes).

Methods

A systematic literature search was performed by using PubMed. Twenty-four studies were included in the meta-analysis based on the inclusion and exclusion criteria. In total, there are 1652 independent participants.

Results

The result showed that high expression levels of lncRNAs were demonstrated to be associated with poor overall survival (OS) (HR = 2.33, 95%CI: 1.51–2.39, p < 0.01) in bladder carcinoma, but there was no significant correlation between lncRNAs level and recurrence-free survival (RFS) (pooled HR = 1.57, 95%CI 0.69–3.56, p = 0.284), and progression-free survival (PFS) (pooled HR = 1.37, 95%CI 0.79–2.38, p = 0.269). Additionally, increased lncRNAs expression was found to be moderately correlated with tumor stage and progression (II/III/IV vs. I, OR = 3.20, 95%CI: 1.72–5.98, p < 0.001). In addition, elevated lncRNAs expression predicted lymph node metastasis (LNM) significantly (pooled OR = 2.29, 95 % CI 1.33–3.95, p < 0.01). No significant heterogeneity was observed among studies except lymph node metastasis.

Conclusion

In conclusion, high expression levels of lncRNAs were demonstrated to be associated with poor OS and positive LNM, and lncRNAs might be potential prognostic markers in bladder cancer.

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.

Novel Tumor Suppressor lncRNA Growth Arrest-Specific 5 (GAS5) In Human Cancer

Long noncoding RNAs (lncRNAs) play crucial regulatory roles in fundamental biological processes, and deregulations of lncRNAs have been linked to numerous human diseases, especially cancers. Of particular interest in this regard is lncRNA GAS5, which is mainly identified as a tumor suppressor in several cancers. GAS5 was significantly low expressed in multiple cancers and was associated with clinic-pathological characteristics and patient survival, indicating a novel potential diagnostic and prognostic biomarker, and a therapeutic target for cancer. Functionally, GAS5 is involved in cell proliferation, metastasis, invasion, apoptosis, epithelial-mesenchymal transition (EMT), and drug resistance, among others, via multiple molecular mechanisms, such as binding to DNA sequences, forming RNA-DNA triplex complex, triggering or suppressing the expression of genes, binding proteins to form chromatin-modifying complex, which activates or represses gene expression, and acting as miRNA sponge to suppress miRNA expression, leading to regulation of miRNA target genes. This review provides an overview of the current state of knowledge and role of GAS5 in clinical relevance, biological functions and molecular mechanisms underlying the dysregulation of expression and function of GAS5 in cancer. Finally, the potential prospective role as diagnostic and prognostic biomarker and therapeutic target in cancer is discussed.

Long non-coding RNA GAS5 inhibits DDP-resistance and tumor progression of epithelial ovarian cancer via GAS5-E2F4-PARP1-MAPK axis

Background

Epithelial ovarian cancer (EOC) is the malignant tumor of the female reproductive system with the highest fatality rate. Tolerance of chemotherapeutic drugs like cisplatin (DDP) occurring in very early stage is one of the important factors of the poor prognosis of epithelial ovarian cancer. Here we aim to study the dysregulation of a particular long noncoding RNA, lncRNA GAS5, and its role in EOC progression.

Methods

The low expression of lncRNA GAS5 in EOC tissues and OC cell lines was determined by microarray analyses and Real-Time qPCR. Flow cytometer assays were used to detect cell cycle and apoptosis of OC cells. CCK8 assay were performed to investigate the DDP sensitivity of OC cells. Western blot was carried out to detect cell growth markers, apoptotic markers, PARP1, E2F4, MAPK pathway protein expression and other protein expression in OC cell lines. The binding of GAS5 and E2F4 were proved by RNA pull-down and RIP assay. The effect of E2F4 on PARP1 were determined by CHIP-qPCR assay and luciferase reporter assay. The effect of lncRNA GAS5 on OC cells was assessed in vitro and in vivo.

Results

By microarray (3 EOC tissues νs. 3 normal ovary tissues) and RT- qPCR (53 EOC tissues νs. 10 normal ovary tissues) we identified lncRNA GAS5 to be dramatically low expressed in EOC samples and correlated with prognosis. Compared with sensitive cell lines, GAS5 was also low expressed in DDP resistant OC cell lines, and over-expression of GAS5 significantly enhanced the sensitivity of OC cells to DDP in vivo and in vitro. Meanwhile the over-expression of GAS5 also caused OC cells G0/G1 arrest and apoptosis increase. Mechanistically, GAS5 might regulate PARP1 expression by recruiting the transcription factor E2F4 to its promoter, and then affect the MAPK pathway activity. Due to the 5’TOP structure, GAS5 could be regulated by transcription inhibitor rapamycin in OC cells.

Conclusion

Here we explored the specific mechanisms of EOC cisplatin resistance and tumor progress due to lncRNA-GAS5, presented the GAS5-E2F4-PARP1-MAPK axis and its role in OC drug-sensitivity and progression for the first time, and the results may provide experimental basis for clinical application.

Curcumin Combination Chemotherapy: The Implication and Efficacy in Cancer

Many chemotherapeutic drugs have been used for the treatment of cancer, for instance, doxorubicin, irinotecan, 5-fluorouracil, cisplatin, and paclitaxel. However, the effectiveness of chemotherapy is limited in cancer therapy due to drug resistance, therapeutic selectivity, and undesirable side effects. The combination of therapies with natural compounds is likely to increase the effectiveness of drug treatment as well as reduce the adverse outcomes. Curcumin, a polyphenolic isolated from Curcuma longa, belongs to the rhizome of Zingiberaceae plants. Studies from in vitro and in vivo revealed that curcumin exerts many pharmacological activities with less toxic effects. The biological mechanisms underlying the anticancer activity of co-treatment curcumin and chemotherapy are complex and worth to discuss further. Therefore, this review aimed to address the molecular mechanisms of combined curcumin and chemotherapy in the treatment of cancer. The anticancer activity of combined nanoformulation of curcumin and chemotherapy was also discussed in this study. Taken together, a better understanding of the implication and underlying mechanisms of action of combined curcumin and chemotherapy may provide a useful approach to combat cancer diseases.

A Single Nucleotide Polymorphism in GAS5 lncRNA is Associated with Risk of Bladder Cancer in Iranian Population

Down-regulation of the long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) has a pathogenic role in bladder cancer. Moreover, genomic variants of this lncRNA have been associated with risk of diverse cancers. In the present project, we genotyped two putative functional SNPs (rs2067079 and rs6790) in 122 bladder cancer patients and 150 age- and sex-matched healthy subjects. The rs2067079 was associated risk of bladder cancer in recessive inheritance model (TT vs.CC + CT: OR (95% Confidence interval (CI)) = 2.67 (1.27-5.62), adjusted P value = 0.02). The T G haplotype (rs2067079 and rs6790) increased the risk of bladder cancer in the assessed population (OR (95% CI) = 1.73 (1.18-2.56), adjusted P value = 0.02). Consequently, in the current project we introduced a novel risk locus for bladder cancer in Iranian population.

MicroRNA-101-3p advances cisplatin sensitivity in bladder urothelial carcinoma through targeted silencing EZH2

Objective: Chemotherapy is a major therapeutic method for bladder urothelial carcinoma (BUC), which can effectively improve the prognosis of BUC patients, but the chemoresistance often leads to chemotherapy failure. This study will research the regulatory roles and molecular mechanism of miR-101-3p in BUC chemoresistance.

Materials and Methods: The quantitative real-time PCR was used to detect the expression of miRNA-101-3p and EZH2. The proliferation and chemoresistance were analyzed by CCK8 assay. Luciferase reporter assay was used to verify the combination between miR-101-3p and EZH2. Protein expression was detected by Western blotting. Flow cytometry was used to examine apoptosis rate.

Results: The miR-101-3p expression was down-regulated in cisplatin (CDDP) resistant BUC cell line (T24/CDDP) and tissues, and was positively related to sensitivity of BUC to CDDP. In T24/CDDP cells, the up-regulation of miR-101-3p decreased the half maximal inhibitory concentration (IC50) to CDDP, depressed the expression of MRP1 protein, promote the CDDP-induced cytotoxicity, and advanced CDDP sensitivity. A series of in vitro experiments certified the EZH2 gene was a target gene of miR-101-3p, including luciferase reporter assay, western blotting and so on. Up-regulation of EZH2 largely reversed the regulatory effects of miR-101-3p enhancement on CDDP sensitivity in T24/CDDP cells.

Conclusion: The expression of miR-101-3p is positively related to CDDP sensitivity of BUC, miR-101-3p advances sensitivity of BUC to CDDP through targeted silencing EZH2.

Long non-coding RNA GHET1 contributes to chemotherapeutic resistance to Gemcitabine in bladder cancer

PURPOSE

Bladder cancer (BC) ranks first in the incidence of urogenital tumors in China and second only to prostate cancer in the West. This study will clarify the roles and mechanism of lncRNA GHET1 in chemotherapeutic resistance of BC to Gemcitabine.

METHODS

The expression of GHET1 was examined using real-time quantitative PCR. Cell Counting Kit-8 assay was applied to analyze cell proliferation and Gemcitabine sensitivity. Cell apoptosis was detected using Annexin V-FITC/PI double-stained flow cytometry. The expression of ABCC1 protein was examined using Western blotting.

RESULTS

Firstly, the expression of GHET1 was up-regulated in BC, its high expression was relevant to high grade and muscle invasion of BC patients. Secondly, high expression of GHET1 was related to low Gemcitabine sensitivity of BC patients, and GHET1 was highly expressed in Gemcitabine-resistant BC cell lines. Thirdly, knockdown of GHET1 decreased the IC50 of Gemcitabine in Gemcitabine-resistant BC cell lines and advanced the Gemcitabine-induced cytotoxicity; GHET1 promoted Gemcitabine resistance in BC. Finally, knockdown of GHET1 also inhibited the expression of ABCC1 protein in Gemcitabine-resistant BC cells.

CONCLUSIONS

High expression of GHET1 was related with the low sensitivity to Gemcitabine of BC; GHET1 contributed to chemotherapeutic resistance to Gemcitabine in BC through up-regulating ABCC1 expression. Our findings are helpful to expound the molecular mechanism of chemotherapeutic resistance in BC.

Drug Resistance-Related Competing Interactions of lncRNA and mRNA across 19 Cancer Types

Drug resistance is a common cause of treatment failure in cancer therapy, and molecular mechanisms need further exploration. Competing endogenous RNAs (ceRNAs) can influence drug response by participating in various biological processes, including regulation of cell cycle, signal transduction, and so on. In this study, we systematically explored resistance from the perspective of ceRNA modules. First, we constructed a general ceRNA network, involving 83 long non-coding RNAs (lncRNAs) and 379 mRNAs. Next, we identified the drug resistance-related modules for 138 drugs and 19 cancer types, totaling 758 drug-cancer conditions. Function analysis showed that resistance-related biological processes were enriched in these modules, such as regulation of cell proliferation, DNA damage repair, and so on. Pan-drug and pan-cancer analyses revealed some common and specific modules across multiple drugs or cancers. In addition, we also found that drug pairs with common modules have similar structure, indicating high risk for multidrug resistance (MDR). Finally, we speculated that ceRNA pair GAS5-RPL8 could regulate drug resistance because low expression of GAS5 would enhance microRNA (miRNA)-mediated inhibition of RPL8. In total, we investigated the drug resistance by using ceRNA modules and proposed that ceRNA modules may be new markers for drug resistance that indicated a possible novel mechanism.

The role of long non-coding RNA GAS5 in cancers

Long non-coding RNAs (lncRNAs) have shown potential as a biomarker in the diagnosis and prognosis in multiple cancers. LncRNAs are dysregulated in various cancers, playing either oncogenic or tumor suppressive roles. Emerging evidences have proved that the growth arrest-specific 5 (GAS5) lncRNA can function as a tumor suppressor in several cancers. LncRNA GAS5 is downregulated in many types of cancer, regulating cellular processes such as cell proliferation, apoptosis and invasion. The low level of GAS5 expression often elevates capacity of proliferation and predicts poorer prognosis in some cancers. This review aims to summarize the recent published literature on the biogenesis, regulation mechanism and function of GAS5 in different types of cancers and explore its potential for cancer diagnosis, prognosis and treatment.

From biomarkers to therapeutic targets-the promises and perils of long non-coding RNAs in cancer

Biomarker-driven personalized cancer therapy is a field of growing interest, and several molecular tests have been developed to detect biomarkers that predict, e.g., response of cancers to particular therapies. Identification of these molecules and understanding their molecular mechanisms is important for cancer prognosis and the development of therapeutics for late stage diseases. In the past, significant efforts have been placed on the discovery of protein or DNA-based biomarkers while only recently the class of long non-coding RNA (lncRNA) has emerged as a new category of biomarker. The mammalian genome is pervasively transcribed yielding a vast amount of non-protein-coding RNAs including lncRNAs. Hence, these transcripts represent a rich source of information that has the potential to significantly contribute to precision medicine in the future. Importantly, many lncRNAs are differentially expressed in carcinomas and they are emerging as potent regulators of tumor progression and metastasis. Here, we will highlight prime examples of lncRNAs that serve as marker for cancer progression or therapy response and which might represent promising therapeutic targets. Furthermore, we will introduce lncRNA targeting tools and strategies, and we will discuss potential pitfalls in translating these into clinical trials.

Long non-coding RNA BX357664 inhibits cell proliferation and metastasis in human lung cancer

Long non-coding RNAs (lncRNAs) have been investigated in human carcinogenesis. The lncRNA BX357664 has emerged as a novel lncRNA that was initially recognized by a microarray analysis. The present study aimed to identify the expression and functional roles of lncRNA BX357664 in lung cancer. The transcription level of BX357664 was initially revealed to be downregulated in clinical lung cancer tissues and in a series of lung cancer cell lines. Clinical data demonstrated that the high expression of BX357664 was associated with tumor size, distant metastasis and Tumor-Node-Metastasis stage. Following the overexpression of BX357664 in A549 and 95D cells, the potential of cells to form colonies, as well as the proliferation and motility abilities, were revealed to be decreased. Furthermore, the cell cycle was arrested in the G0/G1 phase by BX357664 modulation. Transwell analysis and a wound-healing assay also demonstrated that overexpression of BX357664 in A549 and 95D cells significantly inhibited cell migration and invasion. These data suggested that BX357664 inhibits cell proliferation and metastasis in lung cancer. The results of the present study provided evidence that BX357664 is a novel lncRNA that may aid in the diagnosis and treatment of lung cancer.

Growth arrest specific transcript 5 in tumorigenesis process: An update on the expression pattern and genomic variants

Growth arrest-specific 5 (GAS5) is a long non-coding RNA (lncRNA) with diverse functions in regulation of gene expression. Most studies have reported a role for this lncRNA in induction of cell apoptosis and suppression of tumorigenesis process. Although few studies demonstrated up-regulation of this lncRNA in tumor tissues compared to non-tumor tissues of the same origin, the results of in vitro functional studies mostly support the tumor suppressor role for GAS5. A number of recent studies have also shown associations between genomic variants of this gene and risk of cancer in some populations. The role of this lncRNA in modulation of response to anti-cancer regimens has been verified through both in vitro and clinical studies. Taken together, this lncRNA is a putative biomarker and therapeutic target in human malignancies.

Progress in research of long non-coding RNA GAS5 in human tumors

Growth arrest-special transcript 5 (GAS5) is a long non-coding RNA (lncRNA), located on chromosome 1 of the human genome, and it plays an important regulatory role in biological processes such as cell proliferation, apoptosis, migration, and invasion. Recent studies have shown that GAS5 is down-expressed in most tumor tissues, which is closely related to tumorigenesis, tumor development, and prognosis. A better understanding of the pathogenetic mechanisms and biologic functions of lncRNA GAS5 may offer novel opportunities for diagnosis and therapy of tumors. In this review, we summarize the latest research progress of lncRNA GAS5 in various human carcinomas.

Knockdown of long non-coding RNA SNHG5 inhibits malignant cellular phenotypes of glioma via Wnt/CTNNB1 signaling pathway

Objective: Human brain glioma is the most malignant primary intracranial tumor, which has poor prognosis and high mortality. Long noncoding RNAs are considered to take part in cellular phenotypes and are emerging as diagnostic and prognostic biomarkers of glioma. This study will research the effects of Small Nucleolar RNA Host Gene 5 (SNHG5) gene on malignant cellular phenotypes in glioma and explore the possible mechanisms. Materials and Methods: The expression level of SNHG5 was examined using quantitative Real-time PCR in glioma tissues and cell lines. Loss-of-function experiments of SNHG5 together with Enhanced Cell Counting Kit-8, flow cytometry and cell invasion assay were used to investigate the effects of SNHG5 on malignant cellular phenotypes of glioma cells. Finally, luciferase assay and western blotting were applied to determine the activity of WNT/CTNNB1 signaling pathway. Results: SNHG5 gene was high-expressed in glioma tissues and cell lines. Knockdown of SNHG5 gene depressed cell proliferation and invasiveness as well as promoted the apoptosis of U251 and U87 cells. In addition, online database analysis showed SNHG5 was closely related to Wnt/CTNNB1 signaling pathway. Knockdown of SNHG5 inactivated Wnt/CTNNB1 signaling pathway, and the activating of Wnt/CTNNB1 signaling pathway partly restored the influences of SNHG5 knockdown on malignant cellular phenotypes of U251 and U87 cells. Conclusion: SNHG5 gene was high-expressed in glioma, knockdown of SNHG5 inhibits malignant cellular phenotypes of glioma via Wnt/CTNNB1 signaling pathway.

Long Non-coding RNA CDKN2B Antisense RNA 1 Gene Contributes to Paclitaxel Resistance in Endometrial Carcinoma

Endometrial cancer (EC) is the most common malignancy of the female reproductive tract. In this study, we clarified the clinical significance of CDKN2B antisense RNA 1 (CDKN2B-AS) gene, and its effects on paclitaxel sensitivity in EC. Firstly, CDKN2B-AS gene was highly expressed in EC tissues and cell lines. The high-expression of CDKN2B-AS gene was associated with high pathological grade and low paclitaxel sensitivity of EC tissues. Knockdown of CDKN2B-AS gene sensitized Ishikawa/PA and HEC1A/PA cells to paclitaxel, and promoted paclitaxel-induced cytotoxicity. Secondly, the low-expression of miR-125a-5p was closely associated with low paclitaxel sensitivity of EC cells, and up-regulation of miR-125a-5p could increase paclitaxel sensitivity of Ishikawa/PA and HEC1A/PA cells. MiR-125a-5p also mediated the suppressive effects of knockdown of CDKN2B-AS on paclitaxel resistance in EC cells. Thirdly, B-cell lymphoma-2 (Bcl2) and Multidrug Resistance-Associated Protein 4 (MRP4) genes were target genes of miR-125a-5p, which modulated paclitaxel resistance of Ishikawa/PA and HEC1A/PA cells through targeted silencing Bcl2 and MRP4. In conclusion, high-expression of CDKN2B-AS is associated with a poor response to paclitaxel of EC patients, and knockdown of CDKN2B-AS inhibits paclitaxel resistance through miR-125a-5p-Bcl2/MRP4 pathway in EC patients. Our findings help elucidate the molecular mechanisms of chemoresistance in EC patients.

Loss of GAS5 tumour suppressor lncRNA: an independent molecular cancer biomarker for short-term relapse and progression in bladder cancer patients

Background

Bladder cancer (BlCa) heterogeneity and the lack of personalised prognosis lead to patients’ highly variable treatment outcomes. Here, we have analysed the utility of the GAS5 tumour-suppressor lncRNA in improving BlCa prognosis.

Methods

GAS5 was quantified in a screening cohort of 176 patients. Hedegaard et al. (2016) (n = 476) and TCGA provisional (n = 413) were used as validation cohorts. Survival analysis was performed using recurrence and progression for NMIBC, or death for MIBC. Internal validation was performed by bootstrap analysis, and decision curve analysis was used to evaluate the clinical benefit on disease prognosis.

Results

GAS5 levels were significantly downregulated in BlCa and associated with invasive high-grade tumours, and high EORTC-risk NMIBC patients. GAS5 loss was strongly and independently correlated with higher risk for NMIBC early relapse (HR = 2.680, p = 0.011) and progression (HR = 6.362, p = 0.035). Hedegaard et al. and TCGA validation cohorts’ analysis clearly confirmed the association of GAS5 loss with NMIBC worse prognosis. Finally, multivariate models incorporating GAS5 with disease established markers resulted in higher clinical benefit for NMIBC prognosis.

Conclusions

GAS5 loss is associated with adverse outcome of NMIBC and results in improved positive prediction of NMIBC patients at higher risk for short-term relapse and progression, supporting personalised prognosis and treatment decisions.

Long Non-Coding RNA (lncRNA) Growth Arrest Specific 5 (GAS5) Suppresses Esophageal Squamous Cell Carcinoma Cell Proliferation and Migration by Inactivating Phosphatidylinositol 3-kinase (PI3K)/AKT/Mammalian Target of Rapamycin (mTOR) Signaling Pathway

BACKGROUND lncRNA GAS5 acts as a tumor-suppressor gene in various types of malignancies, but its involvement in esophageal cancer has not been well studied. MATERIAL AND METHODS A total of 112 patients with esophageal cancer and 55 volunteers with normal physiological conditions were included in this study. Tumor tissues and adjacent healthy tissues were collected from esophageal cancer patients and blood was extracted from patients and controls. Expression of GAS5 in those tissues was detected by qRT-PCR. All patients were followed up for 5 years and diagnostic and prognostic values of serum GAS5 for esophageal cancer were investigated by ROC curve analysis and survival curve analysis, respectively. Effects of GAS5 expression on cell proliferation and migration were investigated by CCK-8 assay and Transwell cell migration assay, respectively. Effects of GAS5 overexpression on expression of PI3K/AKT/mTOR-related proteins were explored by Western blot analysis. RESULTS GAS5 expression level was lower in tumor tissues than in adjacent healthy tissues. Serum level of GAS5 was lower in cancer patients than in healthy controls, and serum level of GAS5 was decreased with increase in stage of primary tumor (T stage). GAS5 overexpression inhibited tumor cell proliferation and migration, while treatment with PI3K activator reduced the inhibitory effects. GAS5 overexpression decreased the expression level of PI3K and phosphorylation levels of Akt and mTOR in esophageal cancer cells, while PI3K activator treatment showed no significant effects on GAS5 expression. CONCLUSIONS GAS5 was downregulated in esophageal cancer patients compared to healthy controls, and GAS5 overexpression suppressed proliferation and migration of esophageal cancer cells by inactivating the PI3K/AKT/mTOR pathway.

Non-coding RNA NEAT1/miR-214-3p contribute to doxorubicin resistance of urothelial bladder cancer preliminary through the Wnt/β-catenin pathway

BACKGROUND

Urothelial bladder cancer (UBC) is one of the most lethal urological malignancies in the world. Patients with UBC are routinely given chemotherapy which results in a median survival of 12-15 months. Nuclear-enriched abundant transcript 1 (NEAT1) functions as an oncogene and could be used as a therapeutic target for human UBC. However, the involvement of NEAT1 in doxorubicin (DOX) resistance of UBC has been poorly demonstrated.

METHODS

Quantitative Real-time PCR (qRT-PCR) was used to detect the expression levels of NEAT1 and miR-214-3p in UBC tissues and cells. Bioinformatics prediction, RNA pull-down and qRT-PCR were used to assay the regulation manner of NEAT1 and miR-214-3p. Loss/gain function of NEAT1 and miR-214-3p together with western blot, drug resistance assay and flow cytometry were used to explore the influence of NEAT1 in DOX resistance was correlative with miR-214-3p. Finally, luciferase assay system was applied to determine the Wnt/β-catenin signal activity.

RESULTS

NEAT1 was upregulated and miR-214-3p was downregulated in DOX-resistant UBC tissues and cells. NEAT1 knockdown inhibited J82 and T24 cells to DOX chemosensitivity by negatively regulating miR-214-3p expression. NEAT1/miR-214-3p contributed to DOX resistance of UBC preliminary through the Wnt/β-catenin pathway.

CONCLUSION

NEAT1 contributed to DOX resistance of UBC through the Wnt/β-catenin pathway partly by negatively regulating miR-214-3p expression. Our findings will provide a promising ncRNA targeted therapeutic strategy for UBC with DOX resistance.

Long noncoding RNA neuroblastoma-associated transcript 1 gene inhibits malignant cellular phenotypes of bladder cancer through miR-21/SOCS6 axis

Bladder cancer (BC) is one of the most common tumors in the urinary system. Noncoding RNAs are considered to take part in cellular phenotypes and are emerging as diagnostic and prognostic biomarkers of BC. The aim of this study is to investigate the clinical significance of neuroblastoma- associated transcript 1 (NBAT1) gene and its effects on malignant cellular phenotypes in BC. NBAT1 gene was low-expressed in BC tissues and cell lines and its low-expression was related with high pathological grade and metastasis of BC. Upregulation of NBAT1 gene depressed cell viability and invasiveness of KK47 and T24 cells and arrested KK47 and T24 cells at G1 stage. In addition, NBAT1 could target silence the expression of miR-21-5p in RNA-induced silencing complex-dependent manner. KK47 and T24 cells with miR-21-5p knockdown showed reduced cell viability, G1-stage arrest, and depressed invasiveness. MiR-21-5p mediates the regulatory effects of NBAT1 on malignant cellular phenotypes of BC cells. Moreover, SOCS6 gene was a target gene of miR-21-5p, and miR-21-5p modulated malignant cellular phenotypes of KK47 and T24 cells through targeted silencing of SOCS6. In conclusion, low-expression of NBAT1 is associated with the progress and metastasis of BC, and NBAT1 inhibits malignant cellular phenotypes through miR-21-5p/SOCS6 axis in BC. Our findings help to elucidate the tumorigenesis of BC, and future study will provide a novel therapeutic target for BC.

LncRNA as a diagnostic and prognostic biomarker in bladder cancer: a systematic review and meta-analysis

Background

Bladder cancer is one of the most common urinary malignancies, and has a high recurrence rate and poor outcomes. In order to identify novel diagnostic and prognostic biomarkers for bladder cancer, we conducted a meta-analysis to analyze the association between long non-coding RNA (lncRNA) expression and survival in bladder cancer.

Materials and methods

We searched literature from databases using our inclusion and exclusion criteria. STATA 14.0 software was used to analyze the data from collected studies and to construct the forest plots. A different effect size was selected for each meta-analysis.

Results

After selection, 30 articles were found to be eligible. The present meta-analysis contains data from 13 articles about clinicopathological characteristics, six articles about diagnosis, and 16 articles about prognosis. In the present study, we found that many lncRNAs could function as potential diagnostic and prognostic markers in bladder cancer. Among these findings, UCA1 was expected to be a diagnostic biomarker for bladder cancer, while the aberrant expression of HOTAIR and GAS5 was associated with poor disease-free survival/recurrence-free survival/disease-specific survival.

Conclusion

Overall, the present study is the first meta-analysis to assess the association between expression of lncRNAs and clinical value in patients with bladder cancer. LncRNAs hold promise as novel diagnostic and prognostic markers in bladder cancer.