LncRNA CASC11 promotes TGF-β1, increases cancer cell stemness and predicts postoperative survival in small cell lung cancer

High CASC expression predicts poor prognosis of lung cancer: A systematic review with meta-analysis

BACKGROUND

The long non-coding RNA cancer susceptibility candidate (CASC) has abnormal expression in lung cancer tissues and may correlate with lung cancer prognosis. This study aimed to comprehensively evaluate the association between CASC expression and the cancer prognosis.

METHODS

PubMed, Embase, Web of Science, Google Scholar, Cochrane Library, and China National Knowledge Infrastructure databases were searched until April 1, 2023, to obtain the relevant literature. Studies that met the predefined eligibility criteria were included, and their quality was independently assessed by 2 investigators according to the Newcastle-Ottawa Scale (NOS) score. Detailed information was obtained, such as first author, year of publication, and number of patients. Hazard ratio (HR) with a 95% confidence interval (CI) was extracted and grouped to assess the relationship between CASC expression and cancer prognosis. The dichotomous data was merged and shown as the odds ratio (OR) with a 95% CI was extracted to assess the relationship between CASC expression and clinicopathological parameters.

RESULTS

A total of 12 studies with 746 patients with lung cancer were included in the meta-analysis. The expression levels of lncRNA CASC2 and CASC7 were decreased, while those of CASC9, 11, 15, and 19 were induced in lung cancer tissues compared with paracancerous tissues. In the population with low CASC expression (CASC2 and CASC7), high CASC expression indicated a good lung cancer prognosis (HR = 0.469; 95% CI, 0.271-0.668). Conversely, in the population with high CASC expression (CASC9, 11, 15, and 19), high CASC expression predicted a poor lung cancer outcome (HR = 1.910; 95% CI, 1.628-2.192). High CASC expression also predicted worse disease-free survival (DFS) (HR = 2.803; 95% CI, 1.804-6.319). Combined OR with 95% CI revealed an insignificant positive association between high CASC expression and advanced TNM stage (OR = 1.061; 95% CI, 0.775-1.454), LNM (OR = 0.962; 95% CI, 0.724-1.277), tumor size (OR = 0.942; 95% CI, 0.667-1.330), and histological grade (OR = 1.022; 95% CI, 0.689-1.517).

CONCLUSION

The CASC expression levels negatively correlate with lung cancer prognosis. Therefore, CASC expression may serve as a prognostic marker and a potential therapeutic target for lung cancer.

Comprehensive landscape and future perspective of long noncoding RNAs in non-small cell lung cancer: it takes a village

Long noncoding RNAs (lncRNAs) are a distinct subtype of RNA that lack protein-coding capacity but exert significant influence on various cellular processes. In non-small cell lung cancer (NSCLC), dysregulated lncRNAs act as either oncogenes or tumor suppressors, contributing to tumorigenesis and tumor progression. LncRNAs directly modulate gene expression, act as competitive endogenous RNAs by interacting with microRNAs or proteins, and associate with RNA binding proteins. Moreover, lncRNAs can reshape the tumor immune microenvironment and influence cellular metabolism, cancer cell stemness, and angiogenesis by engaging various signaling pathways. Notably, lncRNAs have shown great potential as diagnostic or prognostic biomarkers in liquid biopsies and therapeutic strategies for NSCLC. This comprehensive review elucidates the significant roles and diverse mechanisms of lncRNAs in NSCLC. Furthermore, we provide insights into the clinical relevance, current research progress, limitations, innovative research approaches, and future perspectives for targeting lncRNAs in NSCLC. By summarizing the existing knowledge and advancements, we aim to enhance the understanding of the pivotal roles played by lncRNAs in NSCLC and stimulate further research in this field. Ultimately, unraveling the complex network of lncRNA-mediated regulatory mechanisms in NSCLC could potentially lead to the development of novel diagnostic tools and therapeutic strategies.

Higher cytotoxic activities of CD8+ T cells and natural killer cells from peripheral blood of early diagnosed lung cancer patients

INTRODUCTION

Cytotoxic (CD8+) and natural killer (NK) cells play critical roles in anti-tumor immunity. Dysfunction in these cells is considered as one of the extrinsic mechanisms for tumor relapse.

AIM

We aimed in this study to assess cytotoxic activities of CD8 + T and NK cells in the peripheral blood from lung cancer patients before and after induction of chemotherapy.

SUBJECTS AND METHODS

Healthy (n = 5) volunteers and lung cancer patients (n = 15:5 before, 5 during, and 5 after induction of chemotherapy) were recruited. Flow cytometry was used to analyze the numbers of CD8 + T cells, NK and CD56+T cells and their intracellular expression of granzyme B (GzB) in fresh peripheral blood mononuclear cells (PBMCs) and after 72 h of their culture in vitro and stimulation with 5 µg/ml Concanavalin A (Con A) and 50ng/ml IL-2). In addition, the plasma levels of inflammatory cytokines were measured using luminex.

RESULTS

After culture, significant increases in the number of GzB expressing cells gated on CD3+, CD4+, CD8 + and NKCD8 + T cells in the PBMCs from lung cancer patients before induction of chemotherapy as compared to control individuals as well as patients during and after induction of chemotherapy. Serum levels of IL-1 and CXCL8 in patients before induction of chemotherapy showed 37- and 40-fold increases, respectively, as compared to control individuals. Both GzB expression and cytokines levels in patients during and after chemotherapy were similar.

CONCLUSION

Polyclonal stimulation of PBMCs can restore the cytolytic activities of cytotoxic CD8 and NK cells from lung cancer patients even after chemotherapy.

A review on the role of CASC11 in cancers

The long non-coding RNA (lncRNA) cancer susceptibility 11 (CASC11) is a newly identified lncRNA located on chromosome 8q24.21. The expression of lncRNA CASC11 has been found to be elevated in different cancer types and the prognosis of the tumor is inversely correlated with the high CASC11 expression. Moreover, lncRNA CASC11 has an oncogenic function in cancers. The biological characteristics of the tumors, such as proliferation, migration, invasion, autophagy, and apoptosis can be controlled by this lncRNA. In addition to interacting with miRNAs, proteins, transcription factors, and other molecules, the lncRNA CASC11 modulates signaling pathways including Wnt/β-catenin and epithelial-mesenchymal transition. In this review, we have summarized studies on the role of lncRNA CASC11 in the carcinogenesis from cell lines, in vivo, and clinical perspectives.

The uprise of RNA biology in neuroendocrine neoplasms: altered splicing and RNA species unveil translational opportunities

Neuroendocrine neoplasms (NENs) comprise a highly heterogeneous group of tumors arising from the diffuse neuroendocrine system. NENs mainly originate in gastrointestinal, pancreatic, and pulmonary tissues, and despite being rare, show rising incidence. The molecular mechanisms underlying NEN development are still poorly understood, although recent studies are unveiling their genomic, epigenomic and transcriptomic landscapes. RNA was originally considered as an intermediary between DNA and protein. Today, compelling evidence underscores the regulatory relevance of RNA processing, while new RNA molecules emerge with key functional roles in core cell processes. Indeed, correct functioning of the interrelated complementary processes comprising RNA biology, its processing, transport, and surveillance, is essential to ensure adequate cell homeostasis, and its misfunction is related to cancer at multiple levels. This review is focused on the dysregulation of RNA biology in NENs. In particular, we survey alterations in the splicing process and available information implicating the main RNA species and processes in NENs pathology, including their role as biomarkers, and their functionality and targetability. Understanding how NENs precisely (mis)behave requires a profound knowledge at every layer of their heterogeneity, to help improve NEN management. RNA biology provides a wide spectrum of previously unexplored processes and molecules that open new avenues for NEN detection, classification and treatment. The current molecular biology era is rapidly evolving to facilitate a detailed comprehension of cancer biology and is enabling the arrival of personalized, predictive and precision medicine to rare tumors like NENs.

The role of stem cells in small-cell lung cancer: evidence from chemoresistance to immunotherapy

Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer, accounting for approximately 15% among all lung cancers. Despite the ability of chemotherapy, the first-line treatment for SCLC, to rapidly shrink tumors, nearly all patients experience recurrence and metastasis within a few months. Cancer stem cells (CSCs) are a small population of tumor cells responsible for tumorigenesis, metastasis, and recurrence after treatment, which play a crucial role in chemoresistance by promoting DNA repair and expression of drug resistance-associated proteins. Thus, targeting CSCs has been successful in certain malignancies. Tumor therapy has entered the era of immunotherapy and numerous preclinical trials have demonstrated the effectiveness of immunotherapeutic approaches targeting CSCs, such as tumor vaccines and chimeric antigen receptor (CAR) T cell, and the feasibility of combining them with chemotherapy. Therefore, a deeper understanding of the interaction between CSCs and immune system is essential to facilitate the advances of new immunotherapies approaches targeting CSCs as well as combination with standard drugs such as chemotherapy. This narrative review summarizes the mechanisms of chemoresistance of CSCs in SCLC and the latest advances in targeted therapies. Thereafter, we discuss the effects of CSCs on tumor immune microenvironment in SCLC and corresponding immunotherapeutic approaches. Eventually, we propose that the combination of immunotherapy targeting CSCs with standard drugs is a promising direction for SCLC therapies.

Non-coding genome in small cell lung cancer between theoretical view and clinical applications

Small cell lung cancer (SCLC) is a highly aggressive cancer of the neuroendocrine system, characterized by poor differentiation, rapid growth, and poor overall survival (OS) of patients. Despite the recent advances in the treatment of SCLC recently, the 2-year survival rate of patients with the cancer is only 14-15%, occasioned by the acquired resistance to drugs and serious off-target effects. In humans, the coding region is only 2% of the total genome, and 20% of that is associated with human diseases. Beyond the coding genome are RNAs, promoters, enhancers, and other intricate elements. The non-coding regulatory regions, mainly the non-coding RNAs (ncRNAs), regulate numerous biological activities including cell proliferation, metastasis, and drug resistance. As such, they are potential diagnostic or prognostic biomarkers, and also potential therapeutic targets for SCLC. Therefore, understanding how non-coding elements regulate SCLC development and progression holds significant clinical implications. Herein, we summarized the recent discoveries on the relationship between the non-coding elements including long non-coding RNAs (lncRNA), microRNAs (miRNAs), circular RNA (circRNA), enhancers as well as promotors, and the pathogenesis of SCLC and their potential clinical applications.

Overexpression of LncRNA MNX1-AS1/PPFIA4 Activates AKT/HIF-1α Signal Pathway to Promote Stemness of Colorectal Adenocarcinoma Cells

Purpose. The purpose of this study was to explore the role of the lncRNA MNX1-AS1 and its related downstream signaling pathways in colorectal adenocarcinoma (COAD). Methods. COAD tissues and cells were prepared and treated with sh-MNX1-AS1, pcDNA-MNX1-AS1, sh-PPFIA4, LY29004, and their controls. CCK8 and colony formation assays were undertaken for evaluating cell proliferation. Tumor cell migratory ability was detected by transwell assay. Apoptosis detection was processed by YO-PRO-1/PI Staining. The regulated relationship between lncRNA MNX1-AS1 and PPFIA4 was confirmed by RIP-ChIP assay. Q-PCR was applied to detect genes related to tumor cell stemness, proliferation, migration, and apoptosis in each group. Finally, a xenograft tumor model was constructed to verify the result in vivo. Results. COAD patients with high expression of the lncRNA MNX1-AS1 have poor prognosis. LncRNA MNX1-AS1 promotes the stemness of COAD cells. PPFIA4 mediates lncRNA MNX1-AS1 expression and affects COAD cell stemness. LncRNA MNX1-AS1 accelerates proliferation and migration, while it suppresses apoptosis. LncRNA MNX1-AS1/PPFIA4 accelerates tumor growth in COAD model. LncRNA MNX1-AS1/PPFIA4 activates the downstream AKT/HIF-1α signaling pathway to promote COAD development. LY29004 significantly inhibits the tumorigenic ability of lncRNA MNX1-AS1 and PPFIA4. Conclusion. LncRNA MNX1-AS1/PPFIA4 activates AKT/HIF-1α signal pathway to promote the stemness of COAD cells, which could be a new target for COAD treatment.

LncRNA-Dependent Mechanisms of Transforming Growth Factor-β: From Tissue Fibrosis to Cancer Progression

Transforming growth factor-β (TGF-β) is a crucial pathogenic mediator of inflammatory diseases. In tissue fibrosis, TGF-β regulates the pathogenic activity of infiltrated immunocytes and promotes extracellular matrix production via de novo myofibroblast generation and kidney cell activation. In cancer, TGF-β promotes cancer invasion and metastasis by enhancing the stemness and epithelial mesenchymal transition of cancer cells. However, TGF-β is highly pleiotropic in both tissue fibrosis and cancers, and thus, direct targeting of TGF-β may also block its protective anti-inflammatory and tumor-suppressive effects, resulting in undesirable outcomes. Increasing evidence suggests the involvement of long non-coding RNAs (lncRNAs) in TGF-β-driven tissue fibrosis and cancer progression with a high cell-type and disease specificity, serving as an ideal target for therapeutic development. In this review, the mechanism and translational potential of TGF-β-associated lncRNAs in tissue fibrosis and cancer will be discussed.

Neuron-specific enolase promotes stem cell-like characteristics of small-cell lung cancer by downregulating NBL1 and activating the BMP2/Smad/ID1 pathway

Little is known about the biological functions of neuron-specific enolase (NSE) as a specific biomarker for small-cell lung cancer (SCLC). Herein, we elucidate the effect and mechanism of NSE on SCLC stem cell-like characteristics. Upregulated NSE expression was observed in spheroid cells. The gain-of-function and loss-of-function approaches demonstrated that modulation of NSE positively regulated cell proliferation, drug resistance, spherical clone formation, tumor growth, and stem cell-like characteristics of SCLC cells. Mechanistic studies revealed that NSE might downregulate the expression of neuroblastoma suppressor of tumorigenicity 1 (NBL1) by interacting with NBL1, thereby attenuating the competitive inhibitory effect of NBL1 on BMP2 and enhancing the interaction between BMP2 and BMPR1A; this, in turn, may activate the BMP2/Smad/ID1 pathway and promote SCLC stem cell-like characteristics. Moreover, overexpression of NBL1or knockdown of BMP2 rescued the NSE-induced stem cell-like characteristics. In clinical specimens, NSE expression was positively associated with ALDH1A1 expression and negatively correlated with NBL1 expression. High NSE and ALDH1A1 expressions and low NBL1 expression were correlated with poor prognosis in patients with SCLC. In summary, our study demonstrated that NSE promoted stem cell-like characteristics of SCLC via NBL1 and the activation of the BMP2/Smad/ID1 pathway.

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.

New Insights into the Importance of Long Non-Coding RNAs in Lung Cancer: Future Clinical Approaches

In mammals, a large part of the gene expression products come from the non-coding ribonucleotide sequences of the protein. These short and long sequences are within the range of tens to hundreds of nucleotides, encompassing more than 200 RNA molecules, and their function is known as the molecular structure of long non-coding RNA (lncRNA). LncRNA molecules are unique nucleotides that have a substantial role in epigenetic regulation, transcription, and post-transcriptional modifications in different ways. According to the results of recent studies, lncRNAs have been shown to assume various roles, including tumor suppression or oncogenic functions in common types of cancer such as lung and breast cancer. These non-coding RNAs (ncRNAs) play a pivotal role in activating transcription factors, managing the ribonucleoproteins, the framework for collecting co-proteins, intermittent processing regulations, chromatin status alterations, and maintaining the control within the cell. Cutting-edge technologies have been introduced to disclose several types of lncRNAs within the nucleus and the cytoplasm, which have accomplished important achievements that are applicable in medicine. Due to these efforts, various data centers have been created to facilitate and modify scientific information related to these molecules, including detection, classification, biological evolution, gene status, spatial structure, status, and location of these small molecules. In the present study, we attempt to present the impacts of these ncRNAs on lung cancer with an emphasis on their mechanisms and functions.

LncRNA CASC11 Promotes Hepatocellular Carcinoma Progression via Upregulation of UBE2T in a m6A-Dependent Manner

Hepatocellular carcinoma (HCC) is one of the most frequent malignancies and the third leading cause of cancer-related deaths worldwide. Besides, it has been revealed that long non-coding RNA (LncRNA) cancer susceptibility candidate 11 (CASC11) is involved in cancer progression. However, the functional role and underlying mechanism of CASC11 in HCC remains largely unknown. In this context, here, it was found that CASC11 was upregulated in HCC tissues and associated with tumor grades, metastasis, and prognosis of HCC patients. Functionally, CASC11 facilitated HCC cell proliferation, migration, and invasion in vitro, and enhanced tumor growth and metastasis in vivo. Mechanistically, CASC11 associated with and stabilized Ubiquitin-conjugating enzyme E2T (UBE2T) mRNA. To be specific, it decreased UBE2T N⁶-methyladenosine (m⁶A) level via recruiting ALKBH5. Moreover, CASC11 inhibited the association between UBE2T mRNA and m⁶A reader protein YTHDF2. Taken together, our findings demonstrate the epigenetic mechanism of CASC11 in the regulation of UBE2T expression and possibly provide a novel therapeutic target for HCC 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.

Downregulation of lncRNA XR_429159.1 Linked to Brain Metastasis in Patients With Limited-Stage Small-Cell Lung Cancer

Purpose: The purpose of this study was to identify aberrant long non-coding RNAs (lncRNAs) and explore the predictive value of lncRNA expression patterns on the risk of brain metastases (BMs) in patients with limited-stage small-cell lung cancer (SCLC). Patients and Methods: We executed an array of lncRNA and mRNA chip assays to examine the expression in peripheral blood mononuclear cells obtained from SCLC patients with BMs and compared the expression patterns against those from patients without BMs to identify lncRNAs associated with BMs. Validation was performed against clinical data to further confirm the relationship between lncRNAs and BM. Kaplan-Meier analysis was applied to estimate the cumulative incidence of BMs, and differences between the groups were analyzed using the log-rank test. Results: The expression of 67 lncRNAs (27 upregulated and 40 downregulated) and 47 mRNAs (20 upregulated and 27 downregulated) was significantly different between the BM and non-BM groups (fold change ≥ 2.0, p-value ≤ 0.05), based on the lncRNA and mRNA chip assays. Four lncRNAs were verified by quantitative real-time polymerase chain reaction (qRT-PCR) to confirm the accuracy of the microarray data, and the results of 11 patient pairs (11 patients with BM and 11 patients without BM) revealed that low LncRNA XR_429159.1 expression was a high-risk factor for BM. Further clinical data showed that the incidence of BM among 25 patients with low-level LncRNA XR_429159.1 expression was 31% at 1 year, compared with 14.3% among the 18 patients with high-level LncRNA XR_429159.1 expression (p = 0.035). Conclusion: Our present study identified the low-level expression of lncRNA XR_429159.1 as a high-risk factor among BM in patients with limited-stage SCLC. LncRNA XR_429159.1 is a critical molecule that regulates SCLC metastasis, involved in the neuroepithelial transforming gene 1 (NET1) pathway, and serum levels of this lncRNA are significantly associated with the risk of BM.

8q24.21 Locus: A Paradigm to Link Non-Coding RNAs, Genome Polymorphisms and Cancer

The majority of the human genome is comprised of non-protein-coding genes, but the relevance of non-coding RNAs in complex diseases has yet to be fully elucidated. One class of non-coding RNAs is long non-coding RNAs or lncRNAs, many of which have been identified to play a range of roles in transcription and translation. While the clinical importance of the majority of lncRNAs have yet to be identified, it is puzzling that a large number of disease-associated genetic variations are seen in lncRNA genes. The 8q24.21 locus is rich in lncRNAs and very few protein-coding genes are located in this region. Interestingly, the 8q24.21 region is also a hot spot for genetic variants associated with an increased risk of cancer. Research focusing on the lncRNAs in this area of the genome has indicated clinical relevance of lncRNAs in different cancers. In this review, we summarise the lncRNAs in the 8q24.21 region with respect to their role in cancer and discuss the potential impact of cancer-associated genetic polymorphisms on the function of lncRNAs in initiation and progression of cancer.

LncRNA DHRS4-AS1 Inhibits the Stemness of NSCLC Cells by Sponging miR-224-3p and Upregulating TP53 and TET1

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death. This study aimed to examine the roles of DHRS4-AS1/miR-224-3p signaling in the cancer cell stemness of NSCLC. Real-time PCR showed that DHRS4-AS1 was downregulated in cancerous tissues, and bioinformatics analysis revealed that high DHRS4-AS1 expression indicated a good prognosis for NSCLC patients. Sphere and colony formation assays showed that DHRS4-AS1 overexpression significantly suppressed NSCLC cell colony formation and stem cell-like properties. DHRS4-AS1 also abrogated the expression of OCT4, SOX2, CD34, and CD133, markedly inhibited the expression of epithelial-mesenchymal transition (EMT)-related factors, N-cadherin, ZEB1, and Vimentin, and increased E-cadherin expression in spheres. Furthermore, luciferase reporter assays and real-time PCR analysis demonstrated that DHRS4-AS1 and miR-224-3p were antagonistically repressed in NSCLC cells. RNA immunoprecipitation (RIP) analysis revealed that DHRS4-AS1 interacted with miR-224-3p. DHRS4-AS1 partially reversed the miR-224-3p-decreased TP53 and TET1, resulting in the inhibition of tumor growth in vivo. Finally, TP53 and TET1 were antagonistically regulated by DHRS4-AS1 and miR-224-3p in NSCLC cells. In conclusion, TP53- and TET1-associated DHRS4-AS1/miR-224-3p axis is an essential mechanism by which NSCLC modulates cancer cell stemness.

Critical roles of the lncRNA CASC11 in tumor progression and cancer metastasis: The biomarker and therapeutic target potential

The frequency of human suffering from cancer is increasing annually across the globe. This has fueled numerous investigations aimed at the prevention and cure of various cancers. Long non-coding RNA (lncRNA) are known to play a crucial role in cancer. For instance, cancer susceptibility candidate 11 (CASC11), as one of the long non-coding RNAs, has been reported to be overexpressed in various tumors. This review elucidates the mechanism by which lncRNA CASC11 regulates tumors' biological processes and affirms its value as a therapeutic target for tumors. Through systematic analysis and review of relevant articles in PubMed, we revealed the pathophysiological mechanism of CASC11 on the tumor by regulating the biological processes of tumor such as proliferation, autophagy, apoptosis, thereby promoting tumor metastasis. We also revealed the regulatory pathways of CASC11 in different tumors, for instance by acting on a variety of microRNAs, oncogenic proteins, carcinogens, and transcription factors. Consequently, CASC11 regulates cancer proliferation, apoptosis, and invasion by altering the WNT/β-catenin signaling pathway and epithelial–mesenchymal transition (EMT). Furthermore, CASC11 expression has a high pertinence with clinical prognosis, suggesting that it is a potential marker for malignant tumors or a clinical adjuvant therapy in the future.

Long noncoding RNA CASC11 promotes hepatocarcinogenesis and HCC progression through EIF4A3-mediated E2F1 activation

BACKGROUND

Growing evidences have been revealing that long noncoding RNAs are vital factors in oncogenesis and tumor development. Among them, cancer susceptibility candidate 11 (CASC11) has displayed an impressively essential role in various kinds of cancers including hepatocellular carcinoma (HCC). Nevertheless, its role and potential mechanism in HCC still remain to be fully investigated.

METHODS

CASC11 expression level was evaluated by real-time polymerase chain reaction, western blotting, and in situ hybridization staining in HCC patients, and its prognostic effect was analyzed. The role of CASC11 in HCC tumorigenesis and progression was investigated by cell proliferation assay, transwell assay, extracellular acidification rate, western blotting, flow cytometry, and an in vivo xenograft model. The interactions among CASC11, E2F transcription factor 1 (E2F1), and eukaryotic translation initiation factor 4A3 (EIF4A3) were explored by using quantitative reverse transcriptase polymerase chain reaction, western blotting, RNA-binding protein immunoprecipitation assay, and chromatin immunoprecipitation assays.

RESULTS

Upregulation of CASC11 was confirmed in HCC tissues and associated with poor prognosis. Loss of function assays showed inhibition of CASC11 expression suppressed HCC cells proliferation, mobility, and glucose metabolism and promoted apoptosis. E2F1 expression significantly decreased after inhibition of CASC11. Rescue experiments illustrated that E2F1 overexpression alleviated the suppression of CASC11 inhibition on HCC progression in vitro and in vivo. Mechanistically, CASC11 recruited EIF4A3 to enhance the stability of E2F1 mRNA. CASC11 and E2F1 impacted the activation of the NF-κB signaling and PI3K/AKT/mTOR pathway and further regulated the expression PD-L1 that is an important target of immunotherapy. In addition, we identified YY1 could modulate CASC11 expression by binding to its promoter.

CONCLUSIONS

Our data revealed that CASC11 promoted the progression of HCC by means of EIF4A3-mediated E2F1 upregulation, indicating CASC11 is a promising diagnostic biomarker and therapeutic target for HCC.

Biological functions of long noncoding RNAs and circular RNAs in small-cell lung cancer

We aim to discuss comprehensively the role of long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) in small-cell lung cancer (SCLC) biology and their clinical utility as cancer biomarkers. We searched the scientific literature to select articles related to the role of lncRNAs and circRNAs in SCLC biology or as cancer biomarkers. We identified that a number of lncRNAs and circRNAs can regulate key biological processes involved in SCLC development, including cell proliferation, metastasis and chemoresistance mainly acting as miRNA sponges. Also, the expression of a few lncRNAs and circRNAs predicted survival outcome depicting their utility as prognostic biomarkers. Further investigations on the role of lncRNAs and circRNAs in SCLC tumors may yield novel therapeutic targets for SCLC.

Long noncoding RNA MACC1-AS1 promotes the stemness of nonsmall cell lung cancer cells through promoting UPF1-mediated destabilization of LATS1/2

The roles of long noncoding RNA (lncRNA) MACC1-AS1 have been revealed in various tumors. This work aims to explore the roles of lncRNA MACC1-AS1 in the stemness of nonsmall cell lung cancer (NSCLC) cells and the underlying mechanism. We showed that overexpression of MACC1-AS1 enhanced the stemness of NSCLC cells, which is evident as the increased expression of cancer stem cell transcription factors, ALDH1 activity, and sphere-formation capacity, while knockdown of MACC1-AS1 decreased it. RNA-sequencing analysis revealed that the Hippo pathway was mostly enriched in NSCLC cell with MACC1-AS1 overexpression. Further mRNA and western blot analysis showed that ectopic expression of MACC1-AS1 regulated the expression LATS1/2, the critical regulator of Hippo pathway. Additionally, it was found that MACC1-AS1 interacted with up-frameshift 1 (UPF1) to modulate mRNA decay of LATS1/2. Overexpression of LAST1/2 attenuated the promoting effects of MACC1-AS1 overexpression on the stemness of NSCLC cells. Therefore, our results demonstrate the effects of the novel MACC1-AS1/UPF1/LATS1/2 axis in NSCLC cell stemness.

LINC00501 Inhibits the Growth and Metastasis of Lung Cancer by Mediating miR-129-5p/HMGB1

Background

The function of LINC00501, a long-non-coding RNA (lncRNA), is unclear at present. According to the Cancer Genome Atlas (TCGA), LINC00501 is highly expressed in lung cancer (LC), but whether it can be adopted as a potential therapy target for LC still needs further research.

Methods

The expression of LINC00501 in LC was analyzed based on the TCGA, and a real-time fluorescent quantitative PCR assay was carried out to quantify LINC00501 in non-small-cell lung cancer (NSCLC). Additionally, bioinformatics analysis, luciferase reporter gene technique, and RNA immunoprecipitation (RIP) were employed to analyze the direct interaction between LINC00501 and miR-129-5p, and CCK-8 and Transwell assays and flow cytometry were employed to analyze the effects of LINC00501 on cell proliferation, invasion, and apoptosis. Furthermore, a Western blot assay was carried out to determine the protein level of HMGB1.

Results

LINC00501 was highly expressed in LC according to the database, and it was found that LINC00501 was upregulated in NSCLC specimens and cells, and the up-regulation indicated an unfavorable prognosis. Besides, knockdown of LINC00501 hindered the proliferation and invasion of NSCLC cells and intensified their apoptosis, and LINC00501 could be adopted as competitive endogenous RNA to regulate HMGB1 and tumorigenesis through miR-129-5p.

Conclusion

LINC00501 is overexpressed in LC and the overexpression indicates poor prognosis of patients. In addition, LINC00501 can inhibit the invasion and migration of LC by mediating miR-129-5p/HMGB1.

Novel long non-coding RNA LINC02323 promotes epithelial-mesenchymal transition and metastasis via sponging miR-1343-3p in lung adenocarcinoma

BACKGROUND

We have previously developed a unique metastasis-associated signature consisting of six long non-coding RNAs (lncRNAs), including a novel lncRNA, namely LINC02323. In the present study, we aimed to investigate the underlying roles of LINC02323 in the migration, invasion and TGF-β-induced epithelial-mesenchymal transition (EMT) of lung adenocarcinoma (LUAD) cells.

METHODS

The distribution of LINC02323 was detected by the nuclear-plasma separation experiment. Cell proliferation was assessd by MTT assay, and cell migration and invation were detected by transwell assays. EMT was detected by RT-qPCR and western blotting. Interaction between miRNA and LINC02323 was predicted by starBase v2.0 and confirmed by the double luciferase reporting system.

RESULTS

LINC02323 was distributed in the cytoplasm and nucleus. The overexpression or deletion of LINC02323 did not affect the proliferation of LUAD cells, while significantly affected the migration and invasion of LUAD cells. TGF-β-induced EMT process was significantly affected by both RNA interference (RNAi) and overexpression of LINC02323. The predicted results showed that there were binding sites between LINC02323 and miR-1343-3p. The expression of LINC02323 was found to be negatively correlated with miR-1343-3p in LUAD by analyzing The Cancer Genome Atlas (TCGA) database. The double luciferase reporting system, RT-qPCR and western blotting experiments confirmed that LINC02323 could bind to miR-1343-3p, which bound to TGF-β receptor 1 (TGFBR1). Inhibition of miR-1343-3p reversed LINC02323 silencing-mediated suppression of migration, invasion and EMT.

CONCLUSIONS

LINC02323 acts as a competing endogenous RNA (ceRNA), which sponged miR-1343-3p to upregulate the TGFBR1 expression and promote the EMT and metastasis in LUAD.

KEY POINTS

SIGNIFICANT FINDINGS OF THE STUDY: LINC02323 promotes epithelial-mesenchymal transition and metastasis via sponging miR-1343-3p in lung adenocarcinoma.

WHAT THIS STUDY ADDS

LINC02323 is a key molecule in the process of invasion and metastasis of LUAD and might be used as a potential target in metastatic cancer.

TGF-β induced EMT and stemness characteristics are associated with epigenetic regulation in lung cancer

Transforming growth factor-β (TGF-β) promotes tumor invasion and metastasis by inducing epithelial-mesenchymal transition (EMT). EMT is often related with acquisition of stemness characteristics. The objective of this study was to determine whether EMT and stemness characteristics induced by TGF-β might be associated with epigenetic regulation in lung cancer. A human normal lung epithelial cell line and four lung cancer cell lines were treated with TGF-β. Transcriptome analysis of BEAS-2B and A549 cells incubated with TGF-β were analyzed through next-generation sequencing (NGS). Western blotting was carried out to investigate expression levels of epithelial and mesenchymal markers. Wound healing and Matrigel invasion assay, sphere formation assay, and in vivo mice tumor model were performed to evaluate functional characteristics of EMT and stemness acquisition. To investigate whether activation of EMT and stem cell markers might be involved in epigenetic regulation of lung cancer, experiment using a DNA methyltransferase inhibitor (5-azacytidine, AZA), methylation-specific PCR (MSP) and bisulfite sequencing were performed. NGS revealed changes in expression levels of EMT markers (E-cadherin, N-cadherin, fibronectin, vimentin, slug and snail) and stem cell markers (CD44 and CD87) in both BEAS-2B and A549 cells. Functional analysis revealed increased migration, invasion, sphere formation, and tumor development in mice after TGF-β treatment. Expression of slug and CD87 genes was activated following treatment with AZA and TGF-β. MSP and bisulfite sequencing indicated DNA demethylation of slug and CD87 genes. These results suggest that TGF-β induced EMT and cancer stemness acquisition could be associated with activation of slug and CD87 gene by their promoter demethylation.

Non-coding RNA profile in lung cancer

Lung cancer is the most frequently diagnosed malignancy and the leading source of cancer-associated mortality. This kind of cancer has heterogeneous nature and is divided into two broad classes of small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). In addition to aberrant expression of several signaling pathways and oncogenes, lung cancer is associated with dysregulation of expression of non-coding RNAs including both long non-coding RNAs (lncRNAs) and miRNAs. These aberrantly expressed transcripts are putative therapeutic targets and diagnostic/ prognostic markers. Integrative assessment of expression of lncRNAs, miRNAs and mRNAs has led to construction of competing endogenous RNA networks in which several lncRNAs act as molecular sponges to inhibit regulatory function of miRNAs on mRNAs. Notably, some of these networks seem to have subtype-specific functions in lung cancer. In this review, we summarize recent findings about the importance of these networks in the pathogenesis of lung cancer and provide a list of onco-miRNAs, tumor suppressor miRNAs, oncogenic lncRNAs and tumor suppressor lncRNAs based on their roles in the carcinogenic process in lung cancer.

MiRNAs and LncRNAs: Dual Roles in TGF-β Signaling-Regulated Metastasis in Lung Cancer

Lung cancer is one of the most malignant cancers around the world, with high morbidity and mortality. Metastasis is the leading cause of lung cancer deaths and treatment failure. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs), two groups of small non-coding RNAs (nc-RNAs), are confirmed to be lung cancer oncogenes or suppressors. Transforming growth factor-β (TGF-β) critically regulates lung cancer metastasis. In this review, we summarize the dual roles of miRNAs and lncRNAs in TGF-β signaling-regulated lung cancer epithelial-mesenchymal transition (EMT), invasion, migration, stemness, and metastasis. In addition, lncRNAs, competing endogenous RNAs (ceRNAs), and circular RNAs (circRNAs) can act as miRNA sponges to suppress miRNAs, thereby mediating TGF-β signaling-regulated lung cancer invasion, migration, and metastasis. Through this review, we hope to cast light on the regulatory mechanisms of miRNAs and lncRNAs in TGF-β signaling-regulated lung cancer metastasis and provide new insights for lung cancer treatment.

TGFβ induces stemness through non-canonical AKT-FOXO3a axis in oral squamous cell carcinoma

Background

FOXO3a has been widely regarded as a tumor suppressor. It also plays a paradoxical role in regulating the cancer stem cells (CSCs), responsible for tumor-initiation, chemo-resistance, and recurrence in various solid tumors, including oral squamous cell carcinoma (OSCC). This study aims to uncover the role of FOXO3a and its importance for a non-canonical pathway of TGFβ in regulating the OSCC stemness.

Methods

We identified FOXO3a expression in OSCC tissues and cell lines using immunohistochemistry and western blot. The correlation between FOXO3a and stemness was evaluated. Stable cell lines with differential expression of FOXO3a were constructed using lentiviruses. The effects of FOXO3a on stem-cell like properties in OSCC was further evaluated in vitro and in vivo. We also explored the effect of TGFβ on FOXO3a with respect to its expression and function.

Findings

Our findings suggest that FOXO3a was widely expressed and negatively correlated with the stemness in OSCC. This regulation can be abolished by TGFβ through phosphorylation, nuclear exclusion, and degradation in the non-Smad pathway. We also observed that non-Smad AKT-FOXO3a axis is essential to regulate stemness of CSCs by TGFβ.

Interpretation

TGFβ induces stemness through non-canonical AKT-FOXO3a axis in OSCC. Our study provides a foundation to understand the mechanism of CSCs and a possible therapeutic target to eliminate CSCs.

LncRNA CASC11 is upregulated in postmenopausal osteoporosis and is correlated with TNF-α

Purpose

In this study, we aimed to investigate the role of lncRNA cancer susceptibility 11 (CASC11) and tumor necrosis factor (TNF-α) in postmenopausal osteoporosis (POP).

Methods and materials

POP patients and healthy controls were included in this study and levels of CASC11 and TNF-α in plasma of those participants were measured by qPCR and Western blot, respectively. ROC curve was used for diagnostic analysis. Patients were followed up for 2 years and the correlations between the levels of CASC11 and TNF-α and disease conditions were analyzed.

Results

We found that CASC11 and TNF-α were both upregulated in plasma of POP patients than in healthy controls. Plasma levels of CASC11 and TNF-α were positively correlated in both POP patients and in healthy controls. Upregulation of CASC11 and TNF-α distinguished POP patients from healthy controls. Treatment and follow-up study showed that high CASC11 levels were significantly correlated with prolonged treatment course and high recurrence rate. Plasma levels of CASC11 and TNF-α decreased after treatment. CASC11 overexpression led to upregulated TNF-α in osteoclasts.

Conclusion

CASC11 is upregulated in POP and is correlated with TNF-α.

The positive feedback loop FOXO3/CASC11/miR-498 promotes the tumorigenesis of non-small cell lung cancer

An increasing number of studies have indicated that long noncoding RNAs (lncRNAs) are involved in the regulation of non-small-cell lung cancer (NSCLC). Nevertheless, there are still numerous undiscovered mechanisms underlying this molecular regulation. Here, the results illustrated that CASC11 is overexpressed in NSCLC tumor tissues and cell lines, which is closely related to the clinical features of NSCLC and poor survival. In functional experiments, CASC11 was shown to promote proliferation and cycle progression and enhance NSCLC tumorigenesis. In mechanical investigations, CASC11 was shown to target the miR-498/FOXO3 axis via a canonical competing endogenous RNA (ceRNA). In return, the transcription factor FOXO3 targets the CASC11 promoter region, thereby accelerating its transcription. Our findings demonstrate a crucial role for CASC11 as an oncogene in promoting NSCLC. These results reveal that CASC11 might be a potential therapeutic target for NSCLC.

Copy number variations primed lncRNAs deregulation contribute to poor prognosis in colorectal cancer

Copy number variations (CNVs) are crucial genetic change elements in malignancies, and lncRNAs deregulation induced by genomic and epigenomic aberrations plays key driving role in tumorigenesis, including colorectal cancer (CRC). However, effects of CNVs associated with lncRNAs in CRC is largely unknown. Here, we perform integrative analysis considering messenger RNA expression levels, DNA methylation and DNA copy numbers from 289 cases of CRC specimens. There are five prognostic subtypes of CRC determined by multi-omics integration, and differentially expressed lncRNAs (DE-lncRNAs) are acquired among five subtypes and normal cases. Finally, CNVs pattern matched with DE-lncRNAs reveals a signature including 10 lncRNAs (LOC101927604, LOC105377267, CASC15, LINC-PINT, CLDN10-AS1, C14orf132, LMF1, LINC00675, CCDC144NL-AS1, LOC284454), conspicuously contributing to poor prognosis in CRC, which can be validated in another independent dataset. Together, our research is interested in copy number changes relevant with lncRNAs, not only expending the spectrum of CNVs, but also perfecting the regulation network of lncRNAs in CRC. The main purpose is to provide novel biomarkers for prognostic managements of CRC patients.

Long noncoding RNA MALAT1 promotes the stemness of esophageal squamous cell carcinoma by enhancing YAP transcriptional activity

The tumor promoting roles of long noncoding RNA (lncRNA) MALAT1 have been revealed in various cancers; however, its roles in esophageal squamous cell carcinoma (ESCC) have not previously been disclosed. In this study, we found that MALAT1 expression was remarkably increased in ESCC cells compared to normal human esophageal epithelial cells. In addition, knockdown of MALAT1 attenuated the stemness of ESCC cells, as evidenced by a decrease in spheroid formation capacity, stemness marker expression and aldehyde dehydrogenase 1 activity. Moreover, MALAT1 knockdown decreased the migration ability of ESCC cells. Notably, knockdown of MALAT1 enhanced the radiosensitivity and chemosensitivity of ESCC cells. We also established that MALAT1 binds directly to Yes-associated protein (YAP), thereby enhancing YAP protein expression and increasing YAP transcriptional activity. Overexpression of YAP partially rescued the effect of MALAT1 knockdown on stemness and radiosensitivity of ESCC cells. Overall, this study has identified that a novel MALAT1-YAP axis promotes the stemness of ESCC cells, and thus could be a potential target for treatment of ESCC.