Long noncoding RNA TCF7 promotes invasiveness and self-renewal of human non-small cell lung cancer cells

Molecular mechanisms of long noncoding RNAs associated with cervical cancer radiosensitivity

Despite advances in cervical cancer screening and human papilloma virus (HPV) vaccines, cervical cancer remains a global health burden. The standard treatment of cervical cancer includes surgery, radiation therapy, and chemotherapy. Radiotherapy (RT) is the primary treatment for advanced-stage disease. However, due to radioresistance, most patients in the advanced stage have an adverse outcome. Recent studies have shown that long noncoding RNAs (lncRNAs) participate in the regulation of cancer radiosensitivity by regulating DNA damage repair, apoptosis, cancer stem cells (CSCs), and epithelial-mesenchymal transition (EMT). In this review, we summarize the molecular mechanisms of long noncoding RNAs in cervical cancer and radiosensitivity, hoping to provide a theoretical basis and a new molecular target for the cervical cancer RT in the clinic.

LncRNA TCF7 contributes to high glucose-induced damage in human podocytes by up-regulating SEMA3A via sponging miR-16-5p

AIMS/INTRODUCTION

Long non-coding RNAs (lncRNAs) exert essential functions in the pathogenesis of diabetic nephropathy (DN). LncRNA T-cell factor 7 (TCF7) and semaphorin-3A (SEMA3A) have been found to be involved in the progression of diabetic nephropathy. However, whether the effect of TCF7 on the pathogenesis of diabetic nephropathy is mediated by SEMA3A remains unclear.

MATERIALS AND METHODS

TCF7, miR-16-5p, and SEMA3A were quantified by a qRT-PCR or immunoblotting method. A CCK-8 assay gauged the cell viability. Measurement of cell apoptosis was done using flow cytometry. RNA immunoprecipitation (RIP), dual-luciferase reporter, and RNA pull-down assays were utilized to assay the targeted interactions among the variables.

RESULTS

The TCF7 and SEMA3A levels were elevated in serum from patients with diabetic nephropathy. TCF7 silencing or SEMA3A depletion ameliorated high glucose (HG)-induced podocyte injury. Moreover, TCF7 silencing protected against HG-induced podocyte injury by down-regulating SEMA3A. TCF7 targeted miR-16-5p, and miR-16-5p targeted SEMA3A. Furthermore, TCF7 affected the expression of SEMA3A by competing specifically for shared miR-16-5p.

CONCLUSIONS

These findings suggested that TCF7 silencing attenuated high glucose-induced podocyte damage partially through the miR-16-5p/SEMA3A regulation cascade.

A kinase inhibitor screen reveals MEK1/2 as a novel therapeutic target to antagonize IGF1R-mediated antiestrogen resistance in ERα-positive luminal breast cancer

Antiestrogen resistance of breast cancer has been related to enhanced growth factor receptor expression and activation. We have previously shown that ectopic expression and subsequent activation of the insulin-like growth factor-1 receptor (IGF1R) or the epidermal growth factor receptor (EGFR) in MCF7 or T47D breast cancer cells results in antiestrogen resistance. In order to identify novel therapeutic targets to prevent this antiestrogen resistance, we performed kinase inhibitor screens with 273 different inhibitors in MCF7 cells overexpressing IGF1R or EGFR. Kinase inhibitors that antagonized antiestrogen resistance but are not directly involved in IGF1R or EGFR signaling were prioritized for further analyses. Various ALK (anaplastic lymphoma receptor tyrosine kinase) inhibitors inhibited cell proliferation in IGF1R expressing cells under normal and antiestrogen resistance conditions by preventing IGF1R activation and subsequent downstream signaling; the ALK inhibitors did not affect EGFR signaling. On the other hand, MEK (mitogen-activated protein kinase kinase)1/2 inhibitors, including PD0325901, selumetinib, trametinib and TAK733, selectively antagonized IGF1R signaling-mediated antiestrogen resistance but did not affect cell proliferation under normal growth conditions. RNAseq analysis revealed that MEK inhibitors PD0325901 and selumetinib drastically altered cell cycle progression and cell migration networks under IGF1R signaling-mediated antiestrogen resistance. In a group of 219 patients with metastasized ER+ breast cancer, strong pMEK staining showed a significant correlation with no clinical benefit of first-line tamoxifen treatment. We propose a critical role for MEK activation in IGF1R signaling-mediated antiestrogen resistance and anticipate that dual-targeted therapy with a MEK inhibitor and antiestrogen could improve treatment outcome.

Long Non-Coding RNAs in Lung Cancer: The Role in Tumor Microenvironment

The development of various therapeutic interventions, particularly immune checkpoint inhibitor therapy, have effectively induced tumor remission for patients with advanced lung cancer. However, few cancer patients can obtain significant and long-lasting therapeutic effects for the limitation of immunological nonresponse and resistance. For this case, it’s urgent to identify new biomarkers and develop therapeutic targets for future immunotherapy. Over the past decades, tumor microenvironment (TME)-related long non-coding RNAs (lncRNAs) have gradually become well known to us. A large number of existing studies have indicated that TME-related lncRNAs are one of the major factors to realize precise diagnosis and treatment of lung cancer. Herein, this paper discusses the roles of lncRNAs in TME, and the potential application of lncRNAs as biomarkers or therapeutic targets for immunotherapy in lung cancer.

LncRNA TCF7 Promotes Epithelial Ovarian Cancer Viability, Mobility and Stemness via Regulating ITGB8

This study aimed to investigate the carcinogenic role of long non-coding RNA T-cell factor 7 (lnc-TCF7) in epithelial ovarian cancer (EOC). Lnc-TCF7 overexpression and shRNA plasmids were transfected into SKOV3 and OVCAR3 cells, followed by measurement of cell proliferation, migration, invasion, apoptosis, stemness, and mRNA profile (via microarray). Besides, lnc-TCF7 expression was measured in tumor and adjacent tissues from 76 EOC patients. Lnc-TCF7 was upregulated in EOC cell lines; its overexpression increased cell proliferation, migration, invasion, but decreased apoptosis and promoted CD44, CD133 expressions, CD44+CD133+ cell proportion, spheres formation efficiency and drug resistance to cisplatin in SKOV3 and OVCAR3 cells. Besides, lnc-TCF7 ShRNA exhibited opposite effects comparing with its overexpression. Microarray analysis revealed 267 mRNAs were modulated by lnc-TCF7 dysregulation, among which ITGB8 was the most dysregulated one, which was validated by subsequent western blot and RT-qPCR. Furthermore, ITGB8 overexpression not only induced proliferation, migration, invasion and stemness, but also attenuated the effect of lnc-TCF7 ShRNA on these functions in SKOV3 and OVCAR3 cells. In addition, lnc-TCF7 was upregulated in tumor tissues and correlated with higher pathological grade, tumor size, International Federation of Gynecology and Obstetrics (FIGO) stage and worse overall survival in EOC patients. Conclusively, lnc-TCF7 regulates multiple oncogenic pathways, promotes proliferation, migration, invasion, stemness via upregulating ITGB8. It also correlates with advanced tumor features and poor prognosis in EOC, implying its potential as a target for EOC treatment.

LncRNAs in tumor microenvironment: The potential target for cancer treatment with natural compounds and chemical drugs

It was thought that originally long non-coding RNAs (lncRNAs) were a kind of RNAs without any encoding function. Recently, a variety of studies have shown that lncRNAs play important roles in many life activities. The abnormal expression of lncRNAs in tumor microenvironment (TME) usually promotes the proliferation, migration, and drug resistance of tumor cells through direct or indirect effects, which also usually predicts the poor prognosis. The regulation of lncRNAs expression in TME could significantly inhibit tumor progress. However, the interaction between lncRNAs and TME has not been fully defined at present. Therefore, this paper provided the systemic summary of their interaction and natural products and chemicals targeting lncRNAs in cancer treatment. Currently, the strategies of cancer treatment still have their limits. Understanding the relationship between TME and lncRNAs can help us to realize breakthrough strategy for tumor treatment.

Natural products: Potential targets of TME related long non-coding RNAs in lung cancer

BACKGROUND

Lung cancer is a significant health concern worldwide due to high mortality and morbidity, despite the advances in diagnosis, treatment, and management. Recent experimental evidence from different models suggested long non-coding RNAs (lncRNAs) as major modulators of cancer stem cells (CSCs) in the tumor microenvironment (TME) to support metastasis and drug resistance in lung cancer. Evidence-based studies demonstrated that natural products interfere with TME functions.

PURPOSE OF STUDY

To establish lncRNAs of TME as novel targets of natural compounds for lung cancer management.

STUDY DESIGN

Current study used a combination of TME and lung CSCs, lncRNAs and enrichment and stemness maintenance, natural products and stem cell management, natural products and lncRNAs, natural products and targeted delivery as keywords to retrieve the literature from Scopus, Web of Science, PubMed, and Google Scholar. This study critically reviewed the current literature and presented cancer stem cells' ability in reprogramming lung TME.

RESULTS

This review found that TME related oncogenic and tumor suppressor lncRNAs and their signaling pathways control the maintenance of stemness in lung TME. This review explored natural phenolic compounds and found that curcumin, genistein, quercetin epigallocatechin gallate and ginsenoside Rh2 are efficient in managing lung CSCs. They modulate lncRNAs and their upstream mediators by targeting signaling and epigenetic pathways. This review also identified relevant nanotechnology-based phytochemical delivery approaches for targeting lung cancer.

CONCLUSION

By critical literature analysis, TME related lncRNAs were identified as potential therapeutic targets, aiming to develop natural product-based therapeutics to treat metastatic and drug-resistant lung cancers.

lncRNA transcription factor 7 is related to deteriorating clinical features and poor prognosis in multiple myeloma, and its knockdown suppresses disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway

Multiple myeloma (MM) remains a challenge to treat, and its precise pathogenic mechanisms have not been fully clarified. The present study aimed to evaluate the relation between long non-coding RNA transcription factor 7 (lnc-TCF7) and clinical features, as well as the prognosis of patients with MM, and to determine the effects of lnc-TCF7-knockdown on the regulation (and regulatory mechanisms) of MM progression. lnc-TCF7 expression was detected in the bone marrow plasma cells of 86 patients with MM and 30 healthy controls. In patients with MM, the clinical data were collected, and event-free survival (EFS) and overall survival (OS) analyses were conducted. In vitro, lnc-TCF7 expression was detected in MM cell lines and normal bone marrow plasma cells. Using Roswell Park Memorial Institute 8226 cells, functional experiments were conducted following lnc-TCF7 short hairpin (sh)RNA transfection, and compensation experiments were performed after lnc-TCF7 shRNA transfection alone and in combination with a microRNA (miR)-203 inhibitor. lnc-TCF7 expression was increased in patients with MM compared with the healthy controls and was positively related to β-2-microglobulin expression and International Staging System stage, while negatively associated with complete response, EFS and OS. In vitro, lnc-TCF7 was upregulated in MM cells compared with normal bone marrow plasma cells, and its knockdown suppressed MM cell proliferation while promoting apoptosis. Compensation experiments showed that miR-203 inhibition promoted MM progression by regulating the Jagged1-Notch1 signaling pathway in lnc-TCF7-knockdown cells. In conclusion, increased lnc-TCF7 expression was related to deteriorating clinical features and prognosis, and lnc-TCF7-knockdown inhibited disease progression by regulating the miR-203-mediated Jagged1-Notch1 signaling pathway activation in MM.

Long non-coding RNA T cell factor 7 is associated with increased disease risk and poor prognosis, and promotes cell proliferation, attenuates cell apoptosis and miR-200c expression in multiple myeloma

The aim of the present study was to investigate the association of long non-coding RNA T cell factor 7 (lncRNA TCF7) with disease risk, prognosis and its cellular function in multiple myeloma (MM). A total of 132 de novo symptomatic patients with MM and 50 controls were enrolled. Plasma cells from patients with MM and controls were separated from bone marrow samples to detect lncRNA TCF7 expression using reverse transcription-quantitative PCR. In addition, treatment responses, event-free survival (EFS) and overall survival (OS) were measured. The effects of lncRNA TCF7 on proliferation, apoptosis and microRNA-200c (miR-200c) expression were assessed by gain- and loss-of-function experiments in RPMI-8226 and U-266 cells. The results demonstrated that lncRNA TCF7 expression was upregulated in patients with MM compared with controls, and the receiver operating characteristic curve revealed that lncRNA TCF7 could distinguish patients with MM from controls with an area under the curve of 0.793 (95% CI, 0.725-0.861). In patients with MM, high lncRNA TCF7 expression was associated with higher β2-microglobulin, more advanced International Staging System stage and increased t (14; 16) mutations. Furthermore, it was demonstrated that lncRNA TCF7 was downregulated in patients with complete response (CR) compared with patients without CR. Furthermore, high lncRNA TCF7 expression predicted worse EFS and OS. lncRNA TCF7 also promoted cell proliferation, whereas it reduced cell apoptosis and miR-200c expression in RPMI-8226 and U-266 cells. In conclusion, the present results suggested that lncRNA TCF7 may be used as a potential biomarker and as a treatment target for MM.

Long non-coding RNA T-cell factor 7 in multiple myeloma: A potential biomarker for deteriorated clinical features and poor prognosis

BACKGROUND

This study aimed to investigate the correlation of long non-coding RNA T-cell factor 7 (lnc-TCF7) with clinical features and prognosis in patients with multiple myeloma (MM).

METHODS

Totally, 216 newly diagnosed symptomatic MM patients and 60 healthy controls (HCs) were enrolled. Bone marrow samples were collected from patients before treatment and from HCs on donation to detect lnc-TCF7 expression in plasma cells by reverse transcription quantitative polymerase chain reaction. Besides, clinical response, progression-free survival (PFS), and overall survival (OS) of patients were assessed.

RESULTS

Lnc-TCF7 expression was increased in patients with MM compared with HCs. Lnc-TCF7 expression was highest in international staging system (ISS) stage III patients, followed by ISS stage II patients, and then ISS stage I patients, while lnc-TCF7 expression was similar in patients with different immunoglobulin subtypes and Durie-Salmon stages. Regarding chromosomal abnormalities, lnc-TCF7 expression positively correlated with t(4; 14) and Del(17p), whereas no correlation of lnc-TCF7 expression with t(14; 16), 1q21 amplification, Del(13q), or hyperdiploid was observed in patients with MM. Furthermore, lnc-TCF7 expression positively correlated with serum creatinine, beta-2-microglobulin, and lactate dehydrogenase in patients. Besides, lnc-TCF7 was negatively associated with complete response but not overall response rate in patients. Additionally, patients with lnc-TCF7 high expression exhibited shorter PFS and OS compared to patients with lnc-TCF7 low expression.

CONCLUSION

Lnc-TCF7 might have clinical value in aiding disease management and prognosis prediction of MM.

Identifying Structural Domains and Conserved Regions in the Long Non-Coding RNA lncTCF7

Long non-coding RNA (lncRNA) biology is a rapidly growing area of study. Thousands of lncRNAs are implicated as key players in cellular pathways and cancer biology. However, the structure–function relationships of these novel biomolecules are not well understood. Recent structural studies suggest that lncRNAs contain modular structural domains, which play a crucial role in their function. Here, we hypothesized that such structural domains exist in lncTCF7, a conserved lncRNA implicated in the development and progression of several cancers. To understand the structure–function relationship of lncTCF7, we characterized its secondary structure using chemical probing methods. Our model revealed structural domains and conserved regions in lncTCF7. One of the modular domains identified here coincides with a known protein-interacting domain. The model reported herein is, to our knowledge, the first structural model of lncTCF7 and thus will serve to direct future studies that will provide fundamental insights into the function of this lncRNA.

Smoking Induced Extracellular Vesicles Release and Their Distinct Properties in Non-Small Cell Lung Cancer

Purpose: Smoking is a strong relative risk factor for lung cancer. Extracellular vesicles (EVs), particularly exosomes, have been implicated in cancers. In this study, we characterized smoking induced extracellular vesicles in smokers with non-small cell lung cancer (NSCLC).

Methods: EVs were isolated from bronchoalveolar lavage (BAL) from smokers and NSCLC patients. EV microRNAs (miRNAs) were analyzed by using a TaqMan microRNA assays. Vesicle mRNAs and long non-coding RNAs (lncRNAs) were measured with quantitative RT-PCR. Tumor associated antigens were examined by Western Blot.

Results: Higher levels of local site EVs are found in the lung of smokers and NSCLC patients. Further, over 90% of lung EVs are round vesicles of approximately 50-200 nm, ie., exosomes. There are 21 EV miRNAs up regulated, while 10 miRNAs under regulated, in smokers when compared to controls (relative fold > 2, p < 0.05). These miRNAs were further observed to be dysregulated in NSCLC patients when compared to smokers. Bioinformatic analysis demonstrated that Proteoglycans, Fatty acid biosynthesis, ErbB, Hippo, TGF-beta, Wnt, Rap1, AMPK and Ras pathways were the most prominent pathways enriched in NSCLC EV miRNA signatures. In addition, messenger RNA transcripts including EGFR, KRAS, ALK, MET, LKB1, BRAF, PIK3CA, RET, and ROS1 were significantly higher expressed in lung EVs in smokers and NSCLC patients compared to controls. Long non-coding RNAs, including MALAT1, HOTAIR, HOTTIP, AGAP2-AS1, ATB, TCF7, FOXD2-AS1, HOXA11-AS, PCAF1, and BCAR4, were over expressed in EVs from smokers and NSCLC patients. Furthermore, protein levels of tumor associated antigens including BAGE, PD-L1, MAGE-3, and AKAP4 were significantly dysregulated in EVs of smokers and NSCLC patients compared to healthy controls.

Conclusions: In conclusion, these data demonstrated an intrinsic relationship of smoking dysregulated EVs and EVs contained RNA, proteins which may involve in the development of NSCLC.

Long Non-Coding RNA NONHSAT076754 Promotes Invasion and Metastasis in Epithelial Ovarian Cancer

Although accumulating evidence suggests that long non-coding RNAs (lncRNAs) are critical determinants of ovarian cancer development and progression, reports of metastasis-associated lncRNAs are limited. Here, we focused on NONHSAT076754 and explored its expression level, clinical value, biological behavior and molecular basis in epithelial ovarian cancer (EOC) metastasis. The results showed that NONHSAT076754 expression was increased in EOC tissues and cell lines and that this expression was closely related with FIGO stage, high tumor grade and lymph node metastasis. Furthermore, NONHSAT076754 knockdown markedly inhibited EOC cell migration and invasion in vitro. Consistently, the in vivo data from both the bioluminescence imaging and tumor dissection revealed that depletion of NONHSAT076754 reduced EOC metastasis. Mechanically, the pro-metastatic activities of NONHSAT076754 were partially regulated by PTEN and HTATIP2. Further rescue assays validated that knockdown of HTATIP2 remarkably reversed NONHSAT076754 silencer-induced inhibition of EOC cell metastasis. These data indicate that NONHSAT076754 is a vital regulator of EOC metastasis, laying the foundation for lncRNA-based clinical management of EOC aggressiveness and metastasis.

ILK promotes survival and self-renewal of hypoxic MSCs via the activation of lncTCF7-Wnt pathway induced by IL-6/STAT3 signaling

Mesenchymal stem cells (MSCs) have been applied in treating various diseases including myocardial infarction (MI) and achieved a bit of success; however, the decreased survival rate of MSCs after transplantation greatly limited the efficacy for cell therapy. How to improve the MSC survival rate in stem cell transplantation has undoubtedly become urgent and genetic engineering may be an ideal and feasible way. In this study, we explored the effects on MSCs survival and self-renewal by overexpression of integrin-linked kinase (ILK) in MSCs under hypoxic stimulation and aimed to reveal the molecular mechanisms from the point of paracrine function of MSCs. We first found that overexpression of ILK induced the expression and secretion of IL-6 increased significantly in MSCs under hypoxic stimulation, and the survival and self-renewal of MSCs exposed to hypoxia were enhanced after ILK overexpression. Then the activation of JAK2/STAT3 signaling was detected because of the increased IL-6, and an lncRNA, named lncTCF7, was upregulated remarkably, promoting the activation of Wnt pathway that was required for keeping cell viability and stemness of MSCs. Moreover, we further verified that inhibition of STAT3 signaling by WP1066 and silencing lncTCF7 expression eliminated the protective effects of ILK overexpression on cell survival and self-renewal of MSCs under hypoxic sitmulation. In conclusion, our results uncovered a novel function of ILK to promote MSC survival and self-renewal, suggesting more application potentials of MSC cell therapy on MI.

Long non-coding RNA TCF7 contributes to the growth and migration of airway smooth muscle cells in asthma through targeting TIMMDC1/Akt axis

BACKGROUND

Long noncoding RNAs (lncRNAs) have been revealed to participate in cellular biological processes in multiple diseases, including asthma. Nevertheless, the role of lncRNA TCF7 (lncTCF7) in airway smooth muscle cells (ASMCs) is still covered.

METHODS

The expression of lncTCF7 and TIMMDC1 in ASMCs from 12 asthma patients and 12 healthy controls were detected using qRT-PCR. Then MTT assay, EdU assay and transwell assay were conducted respectively to assess the impact of lncTCF7 on ASMCs viability, proliferation and migration. Besides, western blotting was performed to determine the protein levels of TIMMDC1 and AKT/p-AKT.

RESULTS

We discovered that lncTCF7 and TIMMDC1 were upregulated in asthma groups and lncTCF7 improved ASMCs viability/proliferation and migration. In addition, lncTCF7 regulated TIMMDC1 expression indeed and PDGF-BB treated ASMCs exhibited elevated levels of lncTCF7 and TIMMDC1. Moreover, lncTCF7 suppression diminished both the mRNA and protein levels of TIMMDC1 and markedly reduced p-AKT level which could be enhanced under TIMMDC1 overexpression. Finally, both TIMMDC1 overexpression and AKT activator could restored the inhibitory impacts of lncTCF7 silence on PDGF-BB treated ASMCs.

CONCLUSION

Our study uncovered that lncTCF7 facilitated human ASMCs growth and migration via targeting TIMMDC1 thus activating AKT signaling, providing a novel possible target for asthma therapy.

NEAT1 contributes to the CSC-like traits of A549/CDDP cells via activating Wnt signaling pathway

Long non-coding RNAs (lncRNAs) have been identified to exert crucial roles in tumorigenesis and can serve as novel biomarkers for cancer therapy including lung cancer. Cisplatin is a first-line chemotherapeutic agent in non-small cell lung cancer (NSCLC), but the therapeutic effect is unsatisfactory, partly due to drug resistance. Emerging evidence showed that chemo-resistance is associated with acquisition of cancer stem cell (CSC)-like properties. Cisplatin resistance remains a major obstacle in the treatment of lung cancer, and its mechanism is still not fully elucidated. Meanwhile, CSCs have been involved in tumor metastasis, tumor recurrence and chemotherapy resistance. So far, the mechanism of nuclear enriched abundant transcript 1 (NEAT1) in modulating CSCs in lung cancer remains barely known. Therefore, we aimed to explore the correlation between NEAT1 and cancer stem cells in lung cancer. In our current study, we observed that CSC-like traits were much more enriched in cisplatin-resistant A549/CDDP cells. In addition, NEAT1 was obviously up-regulated in A549/CDDP cells compared with parental A549 cells. Knockdown of NEAT1 decreased the CSC-like properties of A549/CDDP cells through inhibiting tumor cell sphere volume, repressing CSC-like biomarkers levels and restraining CD44 positive cell ratios. Oppositely, overexpression of NEAT1 enhanced the stemness respectively. Moreover, it has been reported that Wnt pathway is implicated in many vital cellular functions including cancer stem cells. Here, it was exhibited that Wnt signal pathway was inactivated by knockdown of NEAT1 whereas activated by NEAT1 overexpression in A549/CDDP cells. Taken these together, it was indicated that NEAT1 could exert a novel biological role in NSCLC chemo-resistance.

The emerging role of lncRNAs in the regulation of cancer stem cells

BACKGROUND

Tumors contain a functional subpopulation of cells that exhibit stem cell properties. These cells, named cancer stem cells (CSCs), play significant roles in the initiation and progression of cancer. Long non-coding RNAs (lncRNAs) can act at the transcriptional, posttranscriptional and translational level. As such, they may be involved in various biological processes such as DNA damage repair, inflammation, metabolism, cell survival, cell signaling, cell growth and differentiation. Accumulating evidence indicates that lncRNAs are key regulators of the CSC subpopulation, thereby contributing to cancer progression. The aim of this review is to overview current knowledge about the functional role and the mechanisms of action of lncRNAs in the initiation, maintenance and regulation of CSCs derived from different neoplasms. These lncRNAs include CTCF7, ROR, DILC, HOTAIR, H19, HOTTIP, ATB, HIF2PUT, SOX2OT, MALAT-1, CUDR, Lnc34a, Linc00617, DYNC2H1-4, PVT1, SOX4 and ARSR Uc.283-plus. Furthermore, we will illustrate how lncRNAs may regulate asymmetric CSC division and contribute to self-renewal, drug resistance and EMT, thus affecting the metastasis and recurrence of different cancers. In addition, we will highlight the implications of targeting lncRNAs to improve the efficacy of conventional drug therapies and to hamper CSC survival and proliferation.

CONCLUSIONS

lncRNAs are valuable tools in the search for new targets to selectively eliminate CSCs and improve clinical outcomes. LncRNAs may serve as excellent therapeutic targets because they are stable, easily detectable and expressed in tissue-specific contexts.

Knockdown of lncRNA GHET1 suppresses cell proliferation, invasion and LATS1/YAP pathway in non small cell lung cancer

BACKGROUND

The aim in this study was to explore the role of long non-coding RNA GHET1 in development of non small cell lung cancer (NSCLC).

METHODS

LncRNA GHET1 expression levels were analyzed by qRT-PCR in tumor tissues and adjacent normal tissues in NSCLC. Measuring the cell proliferation and invasion abilities by CCK8, cell colony formation and transwell invasion assays. Relative protein expression was analyzed by western blot assays.

RESULTS

Expression of lncRNA GHET1 was notably higher in NSCLC tissues compared with adjacent normal tissues by using qRT-PCR analyses. Higher lncRNA GHET1 expression associated with lymph node metastasis, TNM stage and showed poor outcome in NSCLC patients. Knockdown of lncRNA GHET1 suppressed cell proliferation and invasion capacity and Epithelial-Mesenchymal Transition (EMT) phenomenon of NSCLC cells. Moreover, we demonstrated that knockdown of lncRNA GHET1 suppresses LATS1/YAP pathway signaling pathway by downregulating YAP1 expression in NSCLC cells.

CONCLUSIONS

GHET1 predicted a poor outcome and acted as a tumor-promoting gene in NSCLC. Thus, inhibition of GHET1 may be a potential target of NSCLC treatment.

Long non-coding RNA TCF7 predicts the progression and facilitates the growth and metastasis of colorectal cancer

Long non-coding RNA (lnc)TCF7 has been reported to promote the self‑renewal of human cancer stem cells, and enhance the aggressiveness of human non‑small cell lung cancer and hepatocellular carcinoma cells. However, the effect of lncTCF7 on colorectal cancer (CRC) tumorigenesis and progression is currently unclear. In the present study, reverse transcription‑quantitative polymerase chain reaction results demonstrated that lncTCF7 expression was higher in CRC tissues compared with adjacent normal tissues and was significantly associated with tumor size, differentiation degree, tumor‑node‑metastasis grade, lymph node metastasis and invasion depth. In addition, lncTCF7 demonstrated a high sensitivity and specificity for diagnosing CRC, as determined by receiver operating characteristic curve analysis. Furthermore, lncTCF7 silencing in SW‑620 and HT29 CRC cell lines inhibited the proliferation, cell cycle, migration and invasion of cells, as determined by Cell Counting Kit‑8 assays, propidium iodide (PI) staining and flow cytometry, wound healing assays and Transwell invasion assays, respectively; however, Annexin V/PI double staining and flow cytometry indicated that lncTCF7 silencing did not significantly affect the apoptosis of CRC cells. These results indicate that lncTCF7 may predict the progression, and promote the growth and metastasis, of CRC, and may therefore be a novel diagnostic marker and therapeutic target for CRC treatment.

NEAT1 acts as an inducer of cancer stem cell-like phenotypes in NSCLC by inhibiting EGCG-upregulated CTR1

Long non-coding RNAs (lncRNAs) play significant roles in the pathogenesis of various cancers, including lung cancer. In this study, we aimed to investigate the biological function of lncRNA nuclear enriched abundant transcript 1 (NEAT1) in cancer stem cells (CSCs). CSCs have been suggested as the main cause of tumor metastasis, tumor recurrence, and chemotherapy resistance. The copper transporter 1 (CTR1) has been the focus of many recent studies because of its correlation with cisplatin (CDDP) resistance. So far, the mechanism of how NEAT1 regulates CSCs in NSCLC remains unknown. In the current study, lung cancer stem cells were enriched from the parental NSCLC cells. We observed that NEAT1 was up-regulated while copper transporter 1 (CTR1) was down-regulated in the enriched NSCLC cancer stem cells. Knockdown of NEAT1 was able to decrease the CSC-like properties in NSCLC cells, while over-expression of NEAT1 could contribute to the stemness respectively. Meanwhile, appropriate doses of EGCG restrained the stemness triggered by over-expressing NEAT1 via inducing CTR1 expression. Wnt signal pathway and epithelial-to-mesenchymal transition (EMT) process were involved in NEAT1-induced CSCs in NSCLC. These findings may suggest a novel role of NEAT1 for NSCLC treatment.

lncTCF7 is a negative prognostic factor, and knockdown of lncTCF7 inhibits migration, proliferation and tumorigenicity in glioma

Long noncoding RNAs (lncRNAs) have been shown to play critical roles in cancer. lncTCF7 (gene symbol: WSPAR) has been reported to maintain stemness in hepatocellular carcinoma (HCC) stem cells. However, little is known about the role of lncTCF7 in glioma. The aim of this study was to identify the role of lncTCF7 in the pathogenesis of glioma. We analysed the relationship of lncTCF7 expression with clinicopathological characteristics in glioma patients. Our results showed that lncTCF7 expression was increased in glioma tissues compared with that in normal brain tissues (P < 0.001). Moreover, lncTCF7 was significantly associated with WHO grade (I–II vs. III–IV; P = 0.006) and tumour size (<3 cm vs. T ≥ 3 cm; P = 0.025). Meanwhile, patients with high lncTCF7 expression levels exhibited markedly worse overall survival prognoses (P < 0.01). Loss of function assays revealed that knockdown of lncTCF7 significantly inhibited glioma cell migration, proliferation and tumorigenicity in vitro and in vivo. Furthermore, we found that hypoxia induced lncTCF7 expression in an autocrine manner through IL-6 in glioma. In conclusion, lncTCF7 may play a vital role in glioma progression and serves as a potential prognostic biomarker in glioma patients, providing new targets for glioma therapy.

Roles of Long Noncoding RNAs in Recurrence and Metastasis of Radiotherapy-Resistant Cancer Stem Cells

Radiotherapy is a well-established therapeutic regimen applied to treat at least half of all cancer patients worldwide. Radioresistance of cancers or failure to treat certain tumor types with radiation is associated with enhanced local invasion, metastasis and poor prognosis. Elucidation of the biological characteristics underlying radioresistance is therefore critical to ensure the development of effective strategies to resolve this issue, which remains an urgent medical problem. Cancer stem cells (CSCs) comprise a small population of tumor cells that constitute the origin of most cancer cell types. CSCs are virtually resistant to radiotherapy, and consequently contribute to recurrence and disease progression. Metastasis is an increasing problem in resistance to cancer radiotherapy and closely associated with the morbidity and mortality rates of several cancer types. Accumulating evidence has demonstrated that radiation induces epithelial–mesenchymal transition (EMT) accompanied by increased cancer recurrence, metastasis and CSC generation. CSCs are believed to serve as the basis of metastasis. Previous studies indicate that CSCs contribute to the generation of metastasis, either in a direct or indirect manner. Moreover, the heterogeneity of CSCs may be responsible for organ specificity and considerable complexity of metastases. Long noncoding RNAs (lncRNAs) are a class of noncoding molecules over 200 nucleotides in length involved in the initiation and progression of several cancer types. Recently, lncRNAs have attracted considerable attention as novel critical regulators of cancer progression and metastasis. In the current review, we have discussed lncRNA-mediated regulation of CSCs following radiotherapy, their association with tumor metastasis and significance in radioresistance of cancer.

LEF1-AS1, a long-noncoding RNA, promotes malignancy in glioblastoma

OBJECTIVES

The long-noncoding RNAs (lncRNAs) are identified as new crucial regulators of diverse cellular processes in glioblastoma (GBM) tissues. However, the expression pattern and biological function of lncRNAs remain largely unknown. Here, for the first time, the effects of lncRNA lymphoid enhancer-binding factor 1 antisense RNA 1 (LEF1-AS1) on GBM progression both in vitro and in vivo are investigated.

MATERIALS AND METHODS

Expression profiles of LEF1-AS1 in GBM specimens were investigated by bioinformatics analyses. LEF1-AS1 expression in GBM tissues was detected using a quantitative polymerase chain reaction. LEF1-AS1 expression was inhibited by transfecting the LEF1-AS1-specific small interfering RNAs (siRNAs) and stable cell lines established were inhibited by transfecting si-LEF1-AS1 viruses. The Cell Counting Kit-8, ethynyl deoxyuridine, and colony formation assay were used to examine proliferation function. The flow cytometry detected cell-cycle change and apoptosis. Migration effects were detected by a Transwell assay. The tumor xenografts and immunohistochemistry were performed to evaluate tumor growth in vivo.

RESULTS

In this study, LEF1-AS1 expression was found significantly upregulated in GBM specimens compared with normal tissues. The 5-year overall survival in GBM patients from The Cancer Genome Atlas with high expression of LEF1-AS1 was inferior to that with low expression. It was confirmed that expression of LEF1-AS1 was higher in GBM tissues than normal ones. Knockdown of LEF1-AS1 significantly inhibited the malignancy of GBM cells, including proliferation and invasion, and promoted cell apoptosis. The result of Western blot assays indicated that knockdown of LEF1-AS1-mediated tumor suppression in GBM cells may be via the reduction of ERK and Akt/mTOR signaling activities. Finally, the in vivo experiment also demonstrated that knockdown LEF1-AS1 inhibited the growth-promoting effect of LEF1-AS1 of U87 cells.

CONCLUSION

Our result indicated that lncRNA LEF1-AS1 acts as an oncogene in GBM and may be a pivotal target for this disease.

Long non-coding RNAs associated with non-small cell lung cancer

Lung cancer, with 80–85% being non-small cell lung cancer (NSCLC), is the leading cause of cancer-related death in both men and women. Long non-coding RNAs (lncRNAs), always defined as non-protein-coding RNA molecules longer than 200 nucleotides, are now thought as a new frontier in the study of human malignant diseases including NSCLC. As researches continue, increasing number of roles that lncRNAs play in NSCLC has been found, and more and more evidences show lncRNAs have a close relationship with patients’ response to radiochemotherapy or molecular therapy. The aim of this review is to disclose the roles that lncRNAs play in NSCLC and how lncRANs influence the treatment of NSCLC.

Long Non-Coding RNAs: Key Regulators of Epithelial-Mesenchymal Transition, Tumour Drug Resistance and Cancer Stem Cells

Epithelial mesenchymal transition (EMT), the adoption by epithelial cells of a mesenchymal-like phenotype, is a process co-opted by carcinoma cells in order to initiate invasion and metastasis. In addition, it is becoming clear that is instrumental to both the development of drug resistance by tumour cells and in the generation and maintenance of cancer stem cells. EMT is thus a pivotal process during tumour progression and poses a major barrier to the successful treatment of cancer. Non-coding RNAs (ncRNA) often utilize epigenetic programs to regulate both gene expression and chromatin structure. One type of ncRNA, called long non-coding RNAs (lncRNAs), has become increasingly recognized as being both highly dysregulated in cancer and to play a variety of different roles in tumourigenesis. Indeed, over the last few years, lncRNAs have rapidly emerged as key regulators of EMT in cancer. In this review, we discuss the lncRNAs that have been associated with the EMT process in cancer and the variety of molecular mechanisms and signalling pathways through which they regulate EMT, and finally discuss how these EMT-regulating lncRNAs impact on both anti-cancer drug resistance and the cancer stem cell phenotype.