LncRNA-PCAT-1 promotes non-small cell lung cancer progression by regulating miR-149-5p/LRIG2 axis

From carcinogenesis to therapeutic avenues: lncRNAs and mTOR crosstalk in lung cancer

Long non-coding RNAs (lncRNAs) have been demonstrated to have a crucial function in the modulation of the activity of genes, impacting a variety of homeostatic processes involving growth, survival, movement, and genomic consistency. Certain lncRNAs' aberrant expression has been linked to carcinogenesis, tumor growth, and therapeutic resistance. They are beneficial for the management of malignancies since they can function as cancer-causing or cancer-suppressing genes and behave as screening or prognosis indicators. The modulation of the tumor microenvironment, metabolic modification, and spread have all been linked to lncRNAs in lung cancer. Recent research has indicated that lncRNAs may interact with various mTOR signalling systems to control expression in lung cancer. Furthermore, the route can affect how lncRNAs are expressed. Emphasizing the function of lncRNAs as crucial participants in the mTOR pathway, the current review intends to examine the interactions between the mTOR cascade and the advancement of lung cancer. The article will shed light on the roles and processes of a few lncRNAs associated with the development of lung cancer, as well as their therapeutic prospects.

Long non-coding RNAs: an overview on miRNA sponging and its co-regulation in lung cancer

Lung cancer is the most devastating cause of death among all cancers worldwide, and non-small cell lung cancer (NSCLC) accounts for 80% of all the lung cancer cases. Beyond common genetic research and epigenomic studies, the extraordinary investigations of non-coding RNAs have provided insights into the molecular basis of cancer. Existing evidence from various cancer models highlights that the regulation of non-coding RNAs is crucial and that their deregulation may be a common reason for the development and progression of cancer, and competition of cancer therapeutics. Non-coding RNAs, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), are increasingly recognized as potential cancer biomarkers for early detection and application of therapeutic strategies. The miRNAs have gained importance as master regulators of target mRNAs by negatively regulating their expression. The lncRNAs function as both tumor suppressors and oncogenes, and also compete with miRNAs that influence the translational inhibition processes. This review addresses the role of lncRNAs in lung cancer development, highlights their mechanisms of action, and provides an overview of the impact of lncRNAs on lung cancer survival and progression via miRNA sponging. The improved understanding of lung cancer mechanisms has opened opportunities to analyze molecular markers and their potential therapeutics.

Tumor-Suppressive and Oncogenic Roles of microRNA-149-5p in Human Cancers

Malignant tumors are always a critical threat to human health, with complex pathogenesis, numerous causative factors, and poor prognosis. The features of cancers, such as gene mutations, epigenetic alterations, and the activation and inhibition of signaling pathways in the organism, play important roles in tumorigenesis and prognosis. MicroRNA (miRNA) enables the control of various molecular mechanisms and plays a variety of roles in human cancers, such as radiation sensitivity and tumor immunity, through the regulation of target genes. MiR-149-5p participates in the process and is closely related to lipogenesis, the migration of vascular endothelial cells, and the expression of stem-cell-related proteins. In recent years, its role in cancer has dramatically increased. In this review, we summarize the regular physiological roles of miRNAs, specifically miR-149-5p, in the organism and discuss the tumor-suppressive or oncogenic roles of miR-149-5p in different human cancers with respect to signaling pathways involved in regulation. Possible clinical applications of miR-149-5p in future targeted therapies and prognosis improvement in oncology are suggested.

Circ_0041732 regulates tumor properties of triple-negative breast cancer cells by the miR-149-5p/FGF5 pathway

BACKGROUND

Triple-negative breast cancer (TNBC) is a subtype of breast cancers with a high recurrence and mortality. The important factors promoting the TNBC process have not been fully identified. In this research, the role of a TNBC-related circular RNA (circRNA), circ_0041732, was revealed in TNBC cell tumor properties.

METHODS

The expression levels of circ_0041732, microRNA-149-5p (miR-149-5p) and fibroblast growth factor 5 (FGF5) were detected by quantitative real-time polymerase chain reaction. The protein expression was determined by Western blot analysis or immunohistochemistry assay. Cell proliferation was detected by cell counting kit-8 and cell colony formation assays. Cell apoptosis was analyzed by flow cytometry and caspase-3 activity assays. Cell migration and invasion were evaluated by wound-healing and transwell invasion assays. Cell angiogenic capacity was investigated by a tube formation assay. The targeting relationship between miR-149-5p and circ_0041732 or FGF5 was identified by dual-luciferase reporter and RNA immunoprecipitation assays. The impacts of circ_0041732 knockdown on tumor formation were determined by an in vivo assay.

RESULTS

Circ_0041732 and FGF5 expression were significantly upregulated, whereas miR-149-5p was downregulated in TNBC tissues and cells compared with normal breast tissues and cells, respectively. Circ_0041732 silencing inhibited TNBC cell proliferation, migration, invasion, and tube formation, but induced apoptosis. Additionally, circ_0041732 regulated TNBC cell tumor properties by binding to miR-149-5p. MiR-149-5p also modulated TNBC cell tumor properties by targeting FGF5. Furthermore, circ_0041732 knockdown hindered tumor formation in vivo.

CONCLUSION

Circ_0041732 silencing suppressed TNBC cell tumor properties by decreasing FGF5 expression through miR-149-5p. This finding demonstrated that circ_0041732 had the potential as a therapeutic target for TNBC.

Urinary exosomal long noncoding RNAs serve as biomarkers for early detection of non-small cell lung cancer

Objective: Increasing the efficiency of early diagnosis using noninvasive biomarkers is crucial for enhancing the survival rate of lung cancer patients. We explore the differential expression of non-small cell lung cancer (NSCLC)-related long noncoding RNAs (lncRNAs) in urinary exosomes in NSCLC patients and normal controls to diagnose lung cancer.

Methods: A differential expression analysis between NSCLC patients and healthy controls was performed using microarrays. Gene ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to predict potential functions of lncRNAs in NSCLC. quantitative real-time PCR (QT-PCR) was used to verify microarray results.

Results: A total of 640 lncRNAs (70 up- and 570 down-regulated) were differentially expressed in NSCLC patients in comparison to healthy controls. Six lncRNAs were detected by QT-PCR. GO term and KEGG pathway analyses showed that differential lncRNAs were enriched in cellular component organization or biogenesis, as well as other biological processes and signaling pathways, such as the PI3K-AKT, FOXO, p53, and fatty acid biosynthesis.

Conclusions: The differential lncRNAs in urinary exosomes are potential diagnostic biomarkers of NSCLC. The lncRNAs enriched in specific pathways may be associated with tumor cell proliferation, tumor cell apoptosis, and the cell cycle involved in the pathogenesis of NSCLC.

MiR-149-5p: An Important miRNA Regulated by Competing Endogenous RNAs in Diverse Human Cancers

MicroRNAs (miRNAs) consist of a large family of small, non-coding RNAs with the ability to result in gene silencing post-transcriptionally. With recent advances in research technology over the past several years, the physiological and pathological potentials of miRNAs have been gradually uncovered. MiR-149-5p, a conserved miRNA, was found to regulate physiological processes, such as inflammatory response, adipogenesis and cell proliferation. Notably, increasing studies indicate miR-149-5p may act as an important regulator in solid tumors, especially cancers in reproductive system and digestive system. It has been acknowledged that miR-149-5p can function as an oncogene or tumor suppressor in different cancers, which is achieved by controlling a variety of genes expression and adjusting downstream signaling pathway. Moreover, the levels of miR-149-5p are influenced by several newly discovered long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). However, there is blank about systematic function and mechanism of miR-149-5p in human cancers. In this review, we firstly summarize the present comprehension of miR-149-5p at the molecular level, its vital role in tumor initiation and progression, as well as its potential roles in monitoring diverse reproductive and digestive malignancies.

GCRFLDA: scoring lncRNA-disease associations using graph convolution matrix completion with conditional random field

Long noncoding RNAs (lncRNAs) play important roles in various biological regulatory processes, and are closely related to the occurrence and development of diseases. Identifying lncRNA-disease associations is valuable for revealing the molecular mechanism of diseases and exploring treatment strategies. Thus, it is necessary to computationally predict lncRNA-disease associations as a complementary method for biological experiments. In this study, we proposed a novel prediction method GCRFLDA based on the graph convolutional matrix completion. GCRFLDA first constructed a graph using the available lncRNA-disease association information. Then, it constructed an encoder consisting of conditional random field and attention mechanism to learn efficient embeddings of nodes, and a decoder layer to score lncRNA-disease associations. In GCRFLDA, the Gaussian interaction profile kernels similarity and cosine similarity were fused as side information of lncRNA and disease nodes. Experimental results on four benchmark datasets show that GCRFLDA is superior to other existing methods. Moreover, we conducted case studies on four diseases and observed that 70 of 80 predicted associated lncRNAs were confirmed by the literature.

CircHIF1A regulated by FUS accelerates triple-negative breast cancer progression by modulating NFIB expression and translocation

Emerging evidence has demonstrated that circular RNAs (circRNAs) play critical roles in the development and progression of human cancer. However, the biological functions and underlying mechanisms of circRNAs in triple-negative breast cancer (TNBC) remain to be investigated. In our present study, we found that the novel circRNA circHIF1A was significantly overexpressed in breast cancer tissues and that it was associated with metastasis, poor prognosis, and the TNBC subtype. Gain- and loss-of-function experiments were conducted to investigate the biological roles of circHIF1A in TNBC. Overexpression of circHIF1A significantly promoted TNBC growth and metastasis in vitro and in vivo, while knockdown of circHIF1A exerted the opposite effects. Mechanistically, circHIF1A modulated the expression and translocation of NFIB through posttranscriptional and posttranslational modifications, resulting in the activation of the AKT/STAT3 signaling pathway and inhibition of P21. The RNA binding protein FUS could regulate the biogenesis of circHIF1A by interacting with the flanking intron, and FUS was transcriptionally regulated by NFIB, thus forming the circHIF1A/NFIB/FUS positive feedback loop. Moreover, circHIF1A could be packaged into exosomes and was upregulated in the plasma of breast cancer patients. Our findings indicated that circHIF1A played a critical role in the growth and metastasis of TNBC via a positive feedback loop and that circHIF1A could be a promising biomarker for breast cancer diagnosis and a potential therapeutic target for TNBC treatment.

Overexpression of circ_CELSR1 facilitates paclitaxel resistance of ovarian cancer by regulating miR-149-5p/SIK2 axis

Circular RNAs (circRNAs) have emerged as vital regulators in the chemoresistance of diverse human tumors, including ovarian cancer. In the present study, we attempted to explore the function of circ_CELSR1 in paclitaxel resistance of ovarian cancer. Quantitative real-time PCR (qRT-PCR) was conducted for the expression of circ_CELSR1, miR-149-5p and salt inducible kinase 2 (SIK2). Cell Counting Kit-8 (CCK-8) assay was performed to evaluate the half-maximal inhibitory concentration (IC50) of paclitaxel and cell viability. Colony formation assay was adopted for cell colony formation. Flow cytometry analysis was conducted to analyze cell cycle process and apoptosis. Western blot assay was utilized to determine the protein levels. RNA immunoprecipitation (RIP) and dual-luciferase reporter assays were conducted to verify the association between miR-149-5p and circ_CELSR1 or SIK2. Murine xenograft model assay was carried out to determine the effect of circ_CELSR1 in paclitaxel resistance in vivo. Circ_CELSR1 was upregulated in paclitaxel-resistant ovarian cancer tissues and cells. Circ_CELSR1 knockdown enhanced paclitaxel sensitivity and cell apoptosis and repressed cell viability, colony formation and cell cycle process in paclitaxel-resistant ovarian cancer cells. For mechanism analysis, circ_CELSR1 could positively modulate SIK2 expression via sponging miR-149-5p. MiR-149-5p inhibition effectively restored the impacts of circ_CELSR1 knockdown on paclitaxel resistance and cell progression in paclitaxel-resistant ovarian cancer cells. MiR-149-5p overexpression suppressed paclitaxel resistance and cell progression in paclitaxel-resistant ovarian cancer cells by interacting with SIK2. In addition, circ_CELSR1 silencing impeded paclitaxel resistance of ovarian cancer in vivo. Circ_CELSR1 improved the resistance of ovarian cancer to paclitaxel by regulating miR-149-5p/SIK2 axis.

LncRNA PCAT1 Interacts with DKC1 to Regulate Proliferation, Invasion and Apoptosis in NSCLC Cells via the VEGF/AKT/Bcl2/Caspase9 Pathway

Long noncoding RNAs (lncRNAs) are increasingly recognized as indispensable components of the regulatory network in the progression of various cancers, including nonsmall cell lung cancer (NSCLC). The lncRNA prostate cancer associated transcript 1 (PCAT1) has been involved in tumorigenesis of multiple malignant solid tumors, but it is largely unknown that what is the role of lncRNA-PCAT1 and how it functions in the progression of lung cancer. Herein, we observed that lncRNA PCAT1 expression was upregulated in both human NSCLC tissues and cell lines, which was determined by qualitative polymerase chain reaction analysis. Then, gain-and loss-of-function manipulations were performed in A549 cells by transfection with a specific short interfering RNA against PCAT1 or a pcDNA-PCAT1 expression vector. The results showed that PCAT1 not only promoted NSCLC cell proliferation and invasion but also inhibited cell apoptosis. Bioinformatics and expression correlation analyses revealed that there was a potential interaction between PCAT1 and the dyskerin pseudouridine synthase 1 (DKC1) protein, an RNA-binding protein. Then, RNA pull-down assays with biotinylated probes and transcripts both confirmed that PCAT1 directly bounds with DKC1 that could also promote NSCLC cell proliferation and invasion and inhibit cell apoptosis. Moreover, the effects of PCAT1 and DKC1 on NSCLC functions are synergistic. Furthermore, PCAT1 and DKC1 activated the vascular endothelial growth factor (VEGF)/protein kinase B (AKT)/Bcl-2/caspase9 pathway in NSCLC cells, and inhibition of epidermal growth factor receptor, AKT, or Bcl-2 could eliminate the effect of PCAT1/DKC1 co-overexpression on NSCLC cell behaviors. In conclusion, lncRNA PCAT1 interacts with DKC1 to regulate proliferation, invasion, and apoptosis in NSCLC cells via the VEGF/AKT/Bcl-2/caspase9 pathway.

Circ-FOXM1 knockdown suppresses non-small cell lung cancer development by regulating the miR-149-5p/ATG5 axis

Circular RNAs (circRNAs) have been reported to be related to the development of human cancers. However, the function of circ-FOXM1 in non-small cell lung cancer (NSCLC) was largely unknown. Here, we revealed the role and functional mechanism of circ-FOXM1 in NSCLC progression. The relative expression of circ-FOXM1, microRNA-149-5p (miR-149-5p), and autophagy-related 5 (ATG5) was determined by quantitative real-time polymerase chain reaction (RT-qPCR). Cell Counting Kit-8 (CCK-8), flow cytometry, and transwell assay were employed to assess cell viability, apoptosis, and migration, respectively. The relative protein expression was detected by western blot. Furthermore, mouse xenograft was carried out to analyze the effect of circ-FOXM1 on tumor growth in vivo. In addition, the interaction between miR-149-5p and circ-FOXM1 or ATG5 was predicted by Starbase3.0 and confirmed by the dual-luciferase reporter assay and RNA pull-down assay. Circ-FOXM1 and ATG5 levels were upregulated, while the miR-149-5p level was downregulated in NSCLC tissues and cells. Circ-FOXM1 knockdown suppressed NSCLC cell viability, migration, and autophagy, and induced cell apoptosis. Interestingly, circ-FOXM1 targeted miR-149-5p to upregulate the ATG5 level. Moreover, circ-FOXM1 exerted function through repressing miR-149-5p expression, and miR-149-5p exerted function via inhibiting ATG5 expression. Our results suggested that circ-FOXM1 knockdown attenuated the development of NSCLC through modulating the miR-149-5p/ATG5 axis, providing a theoretical basis for the therapy of NSCLC.

MicroRNA‑149‑3p inhibits cell proliferation by targeting AKT2 in oral squamous cell carcinoma

MicroRNAs (miRs) exhibit oncogenic or tumor suppressive functions that contribute to the initiation and development of various types of human cancer. miR-149-3p has been reported to serve multiple roles in the regulation of proliferation, apoptosis and metastasis. However, the effects and detailed mechanism of miR-149-3p in oral squamous cell carcinoma (OSCC) remain unclear. In the present study, miR-149-3p mimic, mimic control, miR-149-3p inhibitor and inhibitor control were transiently transfected into Cal27 and SCC-9 cells. The viability, proliferation and apoptosis of OSCC cells were determined using Cell Counting Kit-8, colony formation and Annexin V assays, respectively. The mRNA expression levels of miR-149-3p and AKT2 were determined by reverse transcription-quantitative PCR. The protein expression levels of AKT2, cleaved caspase-3 and cleaved PARP were examined by western blot analysis. The binding of miR-149-3p to the AKT2 3′-untranslated region was evaluated by a dual luciferase reporter assay. In the present study, overexpression of miR-149-3p reduced the viability and proliferation of OSCC cells. By contrast, increased cell viability and proliferation was observed in miR-149-3p-deficient OSCC cells. Dual luciferase reporter assay indicated that miR-149-3p significantly decreased the luciferase activity of the wild-type AKT2 3′-untranslated region. Moreover, overexpression of miR-149-3p downregulated the mRNA and protein expression levels of AKT2, suggesting that miR-149-3p was a negative modulator of AKT2. Restoration of AKT2 efficiently reversed the miR-149-3p-mediated reduction in the proliferative capacity of OSCC cells. In addition, miR-149-3p enhanced the sensitivity of OSCC cells to the chemotherapeutic drug 5-fluorouracil. Taken together, the current findings revealed an inhibitory effect of miR-149-3p on the proliferation of OSCC cells through the post-transcriptional suppression of AKT2, and indicated a potential chemosensitizing function of miR-149-3p for the treatment of patients with OSCC.

MAFG-AS1 aggravates the progression of pancreatic cancer by sponging miR-3196 to boost NFIX

BACKGROUND

A host of researches have demonstrated the regulation of long non-coding RNAs (lncRNAs) in the progression of pancreatic cancers (PC). In this study, our main task was to analyze the function of MAF bZIP transcription factor G antisense RNA 1 (MAFG-AS1) in PC.

METHODS

RT-qPCR measured gene expression. Functional experiments, including EdU assay, flow cytometry analysis, TUNEL assay and transwell assay, assessed the biological changes of PC cells. RNA pull down assay, luciferase reporter assay and RIP assay verified the interaction between RNAs.

RESULTS

MAFG-AS1 was lowly expressed in normal pancreatic samples but up-regulated in PC tissues and cell lines. Besides, MAFG-AS1 silence suppressed cell proliferation and migration whereas promoted cell apoptosis in PC. Mechanism assays verified that miR-3196 could bind with MAFG-AS1. Moreover, miR-3196 was discovered to be lowly expressed in PC cell lines, and its overexpression inhibited PC cell growth and migration. Importantly, nuclear factor I X (NFIX), overexpressed in PC cell lines, was validated to be positively modulated by MAFG-AS1 through absorbing miR-3196. Moreover, overexpression of NFIX could countervail the restraining effects of MAFG-AS1 knockdown on the growth and migration of PC cells.

CONCLUSION

MAFG-AS1 had an oncogenic function in the progression of PC via regulating miR-3196/NFIX pathway, and decreasing MAFG-AS1 expression could attenuate PC progression.

LncRNAs in Non-Small-Cell Lung Cancer

Lung cancer is associated with a high mortality, with around 1.8 million deaths worldwide in 2018. Non-small-cell lung cancer (NSCLC) accounts for around 85% of cases and, despite improvement in the management of NSCLC, most patients are diagnosed at advanced stage and the five-year survival remains around 15%. This highlights a need to identify novel ways to treat the disease to reduce the burden of NSCLC. Long non-coding RNAs (lncRNAs) are non-coding RNA molecules longer than 200 nucleotides in length which play important roles in gene expression and signaling pathways. Recently, lncRNAs were implicated in cancer, where their expression is dysregulated resulting in aberrant functions. LncRNAs were shown to function as both tumor suppressors and oncogenes in a variety of cancer types. Although there are a few well characterized lncRNAs in NSCLC, many lncRNAs remain un-characterized and their mechanisms of action largely unknown. LncRNAs have success as therapies in neurodegenerative diseases, and having a detailed understanding of their function in NSCLC may guide novel therapeutic approaches and strategies. This review discusses the role of lncRNAs in NSCLC tumorigenesis, highlighting their mechanisms of action and their clinical potential.

Screening Circular RNAs Related to Acquired Gefitinib Resistance in Non-small Cell Lung Cancer Cell Lines

Background: Gefitinib is a tyrosine kinase inhibitor (TKI) of epidermal growth factor receptor (EGFR) used to treat EGFR mutation-positive patients with non-small cell lung cancer (NSCLC). However, the efficacy of gefitinib is limited by the development of acquired resistance. Studies have shown that circular RNAs (circRNAs) are involved in the acquired resistance to many anticancer agents. However, the expression profiles and functions of circRNAs in gefitinib resistance in NSCLC are poorly understood so far. Methods: In this study, circRNA expression profiling was explored in two gefitinib-resistant NSCLC cell lines (HCC827/GR and PC9/GR) and their parental sensitive cells (HCC827 and PC9) using high-throughput RNA sequencing. Quantitative real-time PCR (qRT-PCR) was used to confirm the expression of selected differentially expressed circRNAs. Bioinformatic tools including gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), network analysis, and Kaplan-Meier plotter database were used to predict the functions and pathways of these differentially expressed circRNAs. Results: We identified 46 and 56 differentially expressed circRNAs in HCC827/GR and PC9/GR cell lines, respectively, compared with those in their parental cell lines. Gene ontology and KEGG pathway analysis identified that the host linear transcripts of these differentially expressed circRNAs were involved in many critical biological pathways and molecular functions. We found that hsa_circ_0000567 was consistently up-regulated, and hsa_circ_0006867 was consistently down-regulated in two resistant cell lines. We further used hsa_circ_0000567 and hsa_circ_0006867 as key circRNAs to construct circRNA-miRNA-mRNA networks. Several target mRNAs of these two circRNAs had been shown to significantly associate with the overall survival of patients with lung cancer. Conclusions: In this study, we generated the comprehensive expression and functional profiles of the differentially expressed circRNAs between gefitinib-resistant and -sensitive NSCLC cells, and showed that dysregulation of circRNAs might play an important role in the development of acquired resistance to gefitinib in NSCLC.

PCAT1: An oncogenic lncRNA in diverse cancers and a putative therapeutic target

The critical roles of long non-coding RNAs (lncRNAs) in the regulation of diverse biological functions has potentiated them as cancer biomarkers. Among these transcripts is the prostate cancer associated transcript 1 (PCAT1) which has been initially shown to exert oncogenic roles in prostate cancer. Further studies revealed its similar roles in various kinds of human malignancies including both solid tumors and hematological malignancies. Animal studies have shown that down-regulation of this lncRNA can attenuate tumor growth in a wide array of cancers including prostate cancer, colorectal cancer, squamous cell carcinoma lung cancer and hepatocellular carcinoma. Studies aimed at identification of diagnostic value of this lncRNA in human cancers reported various values ranging from 0.66 to 0.89 in diverse cancers with the best value reported in multiple myeloma. This lncRNA has a number of putative functional genomic variants such as rs1902432, rs2632159, rs1026411, rs710886, rs16901904 and rs710886 which can modify expression or function of PCAT1 thus altering the risk of human cancers. Based on aberrant expression of PCAT1 in malignancies of diverse origins, this lncRNA can be regarded as a therapeutic target in a vast array of cancers. Thus, modalities for efficient reduction of its expression would be beneficial for several patients.

Long non-coding RNA LOC100133669 promotes cell proliferation in oesophageal squamous cell carcinoma

Objectives

LOC100133669 is a lncRNA whose function during tumorigenesis remains unclear now. Thus, we aimed to explore its clinical significance and function in oesophageal squamous cell carcinoma (ESCC).

Materials and Methods

ISH was used to detect LOC100133669 expression in ESCC tissues. The full‐length LOC100133669 was identified by using RACE assay. Subcellular distribution of LOC100133669 was examined by nuclear/cytoplasmic RNA fractionation and qPCR. The role of LOC100133669 in ESCC cell growth was determined by colony formation, MTT and flow cytometry experiments in vitro, as well as xenograft tumour experiment in vivo. RNA pull‐down assay was performed to find LOC100133669‐interacted protein, which was further examined by RIP, IP, Western blot and rescue experiments.

Results

LOC100133669 was upregulated in ESCC tissues compared with adjacent non‐tumour tissues. High LOC100133669 expression was associated with poor prognosis of patients with ESCC. We defined LOC100133669 to be 831 nt in length and mainly localized in the cytoplasm of ESCC cells. Knockdown of LOC100133669 inhibited ESCC cell proliferation and cell cycle progression, while overexpression of LOC100133669 showed the opposite effects. Furthermore, LOC100133669 could bind to Tim50 and upregulated its protein level through inhibiting ubiquitination. Overexpression of Tim50 in part abolished the LOC100133669 depletion–caused inhibitory effect on ESCC cell proliferation.

Conclusions

LOC100133669 plays an oncogenic role in ESCC and may serve as a promising diagnostic marker and therapeutic target for ESCC patients.

M2 Macrophages Promote HCC Cells Invasion and Migration via miR-149-5p/MMP9 Signaling

The roles of M2 macrophages on promoting tumor progression and chemotherapy resistance have been well studied in many cancers, such as pancreatic cancer, kidney cancer and so on, but its linkage to HCC cells still remains unclear. Here we found that M2 macrophages could alter miR-149-5p to increase MMP9 expression in HCC cells and mechanism dissection revealed that miR-149-5p might directly target the 3'UTR of MMP9-mRNA to suppress its translation. The in vivo orthotopic xenografts mouse model with oemiR-149-5p also validated in vitro data. Together, these findings suggest that M2 macrophages may through altering the miR-149-5p to promote HCC progression and targeting the M2 macrophages/miR149-5P/MMP9 signaling may help in the development of the novel therapies to better suppress the HCC progression.

lncRNA PTAR promotes NSCLC cell proliferation, migration and invasion by sponging microRNA‑101

MicroRNA (miR)‑101 copy loss is an early event in the development of human lung cancer, and it occurs in 29% of all lung cancer incidences. In addition, miR‑101 expression in non‑small cell lung cancer (NSCLC) is known to be downregulated. The aim of the present study was to explore the roles and mechanisms of the long non‑coding (lnc)‑RNA pro‑transition associated RNA (PTAR) on NSCLC cell proliferation, migration and invasion in association with miR‑101. Reverse transcription‑quantitative PCR analysis was performed to detect the expression of lncRNA PTAR in 30 paired human NSCLC tissues and the corresponding para‑tumor tissues. PTAR was amplified and cloned into the expression vector pCDNA3.1. Then, PTAR‑overexpression plasmids or small interfering (si)‑RNA‑PTAR was transfected into A549 cells for 48 h, after which cell proliferation and the cell cycle distribution were evaluated. In addition, Transwell chamber and cell scratch‑wound assays were conducted to analyze A549 cell migration and invasion. A luciferase activity assay was evaluated to determine the interaction between PTAR and miR‑101. Furthermore, our results demonstrated that in human NSCLC tissues and cell lines, lncRNA PTAR expression was upregulated compared with normal lung tissues and cell lines, respectively. Additionally, PTAR transfection was observed to promote A549 cell proliferation, migration and invasion; opposing effects were observed with siRNA‑PTAR transfection. The luciferase activity assay revealed that PTAR could act as a sponge to bind miR‑101. Thus, miR‑101 plays a role in NSCLC tumorigenesis and progression. In conclusion, lncRNA PTAR was proposed to promote NSCLC cell growth through sponging and inactivating miR‑101, which may be a possible mechanism underlying miR‑101 copy loss in human NSCLC.

Polymorphisms in Long Noncoding RNA-Prostate Cancer-Associated Transcript 1 Are Associated with Lung Cancer Susceptibility in a Northeastern Chinese Population

Long noncoding RNAs (lncRNAs) are a new class of potential biomarkers and therapeutic targets for cancer. In this study, we chose four single nucleotide polymorphisms (SNPs) in lncRNA-PCAT1 (rs1026411 G>A, rs12543663 A>C, rs710886 T>C, and rs16901904 T>C) to investigate the association between genetic variant in lncRNA-PCAT1 and susceptibility to lung cancer. The study was a hospital-based case–control study including 561 cancer-free controls and 468 lung cancer cases. Genotyping of four SNPs was conducted by using Taqman^® allelic discrimination methods. All statistical analyses were performed by using IBM SPSS Statistics 22 software. We failed to find significant associations between four SNPs and lung cancer risk in all models. However, polymorphisms in rs1026411 and rs710886 were observed to have significant associations with susceptibility to non-small cell lung cancer (AG vs. GG: odds ratio [OR]^a = 0.701, p* = 0.020 and AA+AG vs. GG: OR^a = 0.711 [superscript “a” refers to OR adjusted by age, gender, and smoking], p* = 0.017 [asterisks “*” refers to p adjusted by age, gender, and smoking] for rs1026411; CT vs. TT: OR^a = 0.723, p* = 0.047 and CC+CT vs. TT: OR^a = 0.729, p* = 0.038 for rs710886). Besides, the rs1026411 polymorphism had a similar association with lung adenocarcinoma risk (AG vs. GG: OR^a = 0.663, p* = 0.019 and AA+AG vs. GG: OR^a = 0.685, p* = 0.020). Polymorphisms in rs710886 and rs16901904 were observed to be associated with lung squamous cell carcinoma risk (CC+CT vs. TT: OR^a = 0.638, p* = 0.040 for rs710886; CC vs. TT: OR^a = 2.582, p* = 0.033 and CC vs. TT+CT: OR^a = 2.381, p* = 0.048 for rs16901904). In addition, there were no significant results in gene–environmental interactions in both additive and multiplicative models. Our results suggested that polymorphisms in lncRNA-PCAT1 might be associated with lung cancer susceptibility in a northeastern Chinese population. The results of gene–environmental interactions were not significant in lung cancer.

Long noncoding RNA PCAT1, a novel serum-based biomarker, enhances cell growth by sponging miR-326 in oesophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) play important roles in the development and progression of human cancers. The lncRNA prostate cancer-associated transcript 1 (PCAT1) has been reported to be involved in multiple human cancers, including oesophageal squamous cell carcinoma (ESCC). However, the detailed biological functions, underlying mechanisms and clinical relevance of PCAT1 in ESCC remain unclear. Here, we confirmed that PCAT1 was highly expressed in ESCC tissues and cell lines. Knockdown of PCAT1 inhibited the growth of ESCC cells, whereas overexpression of PCAT1 showed the opposite effect both in vitro and in vivo. Moreover, knockdown of PCAT1 arrested the cell cycle at G2/M phase, reduced the expression of cyclin B1 and CDC2, and caused cells to be more sensitive to paclitaxel. Furthermore, PCAT1 could bind to miR-326, a tumour suppressor in diverse human cancers. Rescue experiments revealed that enforced expression of miR-326 attenuated the promotive effect of PCAT1 on ESCC cell growth. In addition, we discovered that PCAT1 was present in ESCC cell-derived exosomes, was higher in the serum of ESCC patients than those of healthy volunteer donors, and promoted cell growth through exosomes. Thus, our data indicate that PCAT1 promotes ESCC cell proliferation by sponging miR-326 and may serve as a non-invasive biomarker for ESCC.