Long non-coding RNA FLVCR1-AS1 contributes to the proliferation and invasion of lung cancer by sponging miR-573 to upregulate the expression of E2F transcription factor 3

Long noncoding RNA LINC00858 aggravates the progression of esophageal squamous cell carcinoma via regulating the miR-425-5p/ABL2 axis

Esophageal squamous cell carcinoma (ESCC) is one of the most fatal cancers with high morbidity and mortality, which severely affects people's lives. Long intergenic non-protein coding RNA 858 (LINC00858) was confirmed to promote the progression of colorectal cancer and lung cancer. However, the role of lncRNA LINC00858 is still unknown in ESCC. Herein, the main purpose of research was to explore LINC00858 function and its impact on ESCC cell biological behaviors. RT-qPCR was used to test the expression of LINC00858, miR-425-5p and ABL proto-oncogene 2 (ABL2) in ESCC cells. Functional experiments such as EdU assay, CCK-8 assay, transwell assay and Western blot assay were conducted to investigate the biological behaviors of ESCC cells. Luciferase reporter assay and RIP assay were implemented to determine the binding situation among RNAs. LINC00858 expression was abnormally high in ESCC cells and down-regulation of LINC00858 could restrain the proliferation, invasion, migration and EMT process of ESCC cells. Furthermore, miR-425-5p was proved to be sponged by LINC00858 and was down-regulated in ESCC cells. Besides, we discovered that miR-425-5p could target ABL2. Moreover, knockdown of ABL2 reversed the promoting function of miR-425-5p inhibitor on ESCC progression. LINC00858 aggravated ESCC progression via regulating the miR-425-5p/ABL2 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.

FLVCR1-AS1 and FBXL19-AS1: Two Putative lncRNA Candidates in Multiple Human Cancers

(1) Background: Mounting evidence supports the idea that one of the most critical agents in controlling gene expression could be long non-coding RNAs (lncRNAs). Upregulation of lncRNA is observed in the different processes related to pathologies, such as tumor occurrence and development. Among the crescent number of lncRNAs discovered, FLVCR1-AS1 and FBXL19-AS1 have been identified as oncogenes in many cancer progression and prognosis types, including cholangiocarcinoma, gastric cancer, glioma and glioblastoma, hepatocellular carcinoma, lung cancer, ovarian cancer, breast cancer, colorectal cancer, and osteosarcoma. Therefore, abnormal FBXL19-AS1 and FLVCR1-AS1 expression affect a variety of cellular activities, including metastasis, aggressiveness, and proliferation; (2) Methods: This study was searched via PubMed and Google Scholar databases until May 2022; (3) Results: FLVCR1-AS1 and FBXL19-AS1 participate in tumorigenesis and have an active role in impacting several signaling pathways that regulate cell proliferation, migration, invasion, metastasis, and EMT; (4) Conclusions: Our review focuses on the possible molecular mechanisms in a variety of cancers regulated by FLVCR1-AS1 and FBXL19-AS1. It is not surprising that there has been significant interest in the possibility that these lncRNAs might be used as biomarkers for diagnosis or as a target to improve a broader range of cancers in the future.

LINC00665 up-regulates SIN3A expression to modulate the progression of colorectal cancer via sponging miR-138-5p

Background

Colorectal cancer (CRC) is a malignant tumor affecting people worldwide. Long noncoding RNAs (lncRNAs) is a crucial factor modulating various cancer progression, including CRC. Long intergenic non-protein coding RNA 665 (LINC00665) has been proven as an oncogene in several cancers, but its function in CRC is still unclear.

Methods

QRT-PCR was performed for RNA quantification. Functional assays were designed and carried to test cell phenotype while mechanism experiments were adopted for detecting the interaction of LINC00665, microRNA-138-5p (miR-138-5p) and SIN3 transcription regulator family member A (SIN3A). In vivo experiments were conducted to test LINC00665 function on modulating CRC tumor progression.

Results

LINC00665 displayed high expression in CRC tissues and cells, and promoted tumor progression in vivo. MiR-138-5p displayed abnormally low expression in CRC, and was verified to be sponged by LINC00665. Furthermore, SIN3A, as the downstream mRNA of miR-138-5p, exerted promoting impacts on CRC cells. Rescue experiments certified that overexpressed SIN3A or silenced miR-138-5p could offset the repressed function of LINC00665 knockdown on CRC progression.

Conclusions

LINC00665 could sponge miR-138-5p to up-regulate SIN3A expression, thus accelerating CRC progression.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02176-4.

Positive feedback between lncRNA FLVCR1-AS1 and KLF10 may inhibit pancreatic cancer progression via the PTEN/AKT pathway

BACKGROUND

FLVCR1-AS1 is a key regulator of cancer progression. However, the biological functions and underlying molecular mechanisms of pancreatic cancer (PC) remain unknown.

METHODS

FLVCR1-AS1 expression levels in 77 PC tissues and matched non-tumor tissues were analyzed by qRT-PCR. Moreover, the role of FLVCR1-AS1 in PC cell proliferation, cell cycle, and migration was verified via functional in vitro and in vivo experiments. Further, the potential competitive endogenous RNA (ceRNA) network between FLVCR1-AS1 and KLF10, as well as FLVCR1-AS1 transcription levels, were investigated.

RESULTS

FLVCR1-AS1 expression was low in both PC tissues and PC cell lines, and FLVCR1-AS1 downregulation was associated with a worse prognosis in patients with PC. Functional experiments demonstrated that FLVCR1-AS1 overexpression significantly suppressed PC cell proliferation, cell cycle, and migration both in vitro and in vivo. Mechanistic investigations revealed that FLVCR1-AS1 acts as a ceRNA to sequester miR-513c-5p or miR-514b-5p from the sponging KLF10 mRNA, thereby relieving their suppressive effects on KLF10 expression. Additionally, FLVCR1-AS1 was shown to be a direct transcriptional target of KLF10.

CONCLUSIONS

Our research suggests that FLVCR1-AS1 plays a tumor-suppressive role in PC by inhibiting proliferation, cell cycle, and migration through a positive feedback loop with KLF10, thereby providing a novel therapeutic strategy for PC treatment.

Knockdown of Long Non-coding RNA LINC00200 Inhibits Gastric Cancer Progression by Regulating miR-143-3p/SERPINE1 Axis

BACKGROUND

An increasing number of studies have found that long non-coding RNAs (lncRNAs) play an important role in carcinogenesis and tumor progression, whereas their molecular mechanisms of function remain largely unknown.

AIMS

This study was aimed to explore the biological function and underlying mechanism of a new lncRNA LINC00200 in gastric cancer (GC).

METHODS

qRT-PCR analysis was conducted to examine the LINC00200 expression level in both GC tissues and cell lines. Functional assays were carried out to detect the effect of LINC00200 on GC cell proliferation, invasion and migration. The interaction between LINC00200 and miR-143-3p was confirmed by luciferase reporter assays. Rescue assays were performed to confirm the influence of LINC00200-miR-143-3p-SERPINE1 axis on GC development.

RESULTS

LINC00200 was found to be upregulated in GC tissues and cell lines. Moreover, knockdown of LINC00200 suppressed GC cell proliferation, invasion and migration in vitro and inhibited tumorigenesis in mouse xenografts. Finally, mechanism research indicated that LINC00200 functioned as a ceRNA to sponge for miR-143-3p, thus leading to the disinhibition of its target gene SERPINE1.

CONCLUSIONS

LINC00200 is significantly overexpressed in GC and accelerates GC progression through regulating miR-143-3p/SERPINE1 axis. Our results may provide a potential diagnostic biomarker and therapeutic target for the management of GC patients.

MiR-573 suppresses cell proliferation, migration and invasion via regulation of E2F3 in pancreatic cancer

Background: Pancreatic cancer is among the most lethal malignancies worldwide. In this study, we aimed to determine whether miR-573 could suppress pancreatic cancer cell proliferation, migration, and invasion by targeting E2F3. Materials and Methods: MiR-573 expression in pancreatic cancer tissues and cell lines was measured using real-time PCR. Target genes of miR-573 were screened using bioinformatics tools and confirmed using dual-luciferase reporter assay and real-time PCR. Pancreatic cancer cells were transfected using an miR-573 mimic or siRNA E2F3. Furthermore, cell proliferation, migration, and invasion were assessed using CCK-8, Edu staining, colony-forming assay, wound healing assay, and transwell assay in vitro. The in vivo effects of miR-573 were verified using tumor xenografts. Differential expression and prognostic analyses of miR-573 and E2F3 were visualized using the Kaplan‑Meier plotter and GEPIA. Results: We found that the expression of miR-573 was significantly reduced in pancreatic cancer tissues and cell lines. Overexpression of miR-573 obviously suppressed the proliferation, migration, and invasion of pancreatic cancer cells. The Dual-luciferase assay showed that miR-573 could specifically target E2F3. Furthermore, E2F3 was up-regulated in pancreatic cancer tissues and cell lines and E2F3 down-regulation inhibited the proliferation, migration, and invasion of pancreatic cancer cells. The ectopic expression of miR-573 inhibited xenograft tumor growth in vivo. Results from the Kaplan-Meier analysis and GEPIA showed that patients with a high level of miR-573 had a significantly reduced risk of death while those with a high level of E2F3 displayed significant correlation with the tumor stage and suffered worse prognosis. Conclusions: MiR-573 could suppress the proliferation, migration, and invasion of pancreatic cancer cells by targeting E2F3, thereby establishing miR-573 as a novel regulator of E2F3 and indicating its critical role in tumorigenesis, especially in pancreatic cancer.

Competing endogenous RNAs in lung cancer

Competing endogenous RNAs (ceRNAs) containing microRNA response elements can competitively interact with microRNA via miRNA response elements, which can combine non-coding RNAs with protein-coding RNAs through complex ceRNA networks. CeRNAs include non-coding RNAs (long non-coding RNAs, circular RNAs, and transcribed pseudogenes) and protein-coding RNAs (mRNAs). Molecular interactions in ceRNA networks can coordinate many biological processes; however, they may also lead to ceRNA network imbalance and thus contribute to cancer occurrence when disturbed. Recent studies indicate that many dysregulated RNAs derived from lung cancer may function as ceRNAs to regulate multitudinous biological functions for lung cancer, including tumor cell proliferation, apoptosis, growth, invasion, migration, and metastasis. This study therefore reviewed the research progress in the field of non-coding and protein-coding RNAs as ceRNAs in lung cancer, and highlighted validated ceRNAs involved in biological lung cancer functions. Furthermore, the roles of ceRNAs as novel prognostic and diagnostic biomarkers were also discussed. Interpreting the involvement of ceRNAs networks in lung cancer will provide new insight into cancer pathogenesis and treatment strategies.

HAND2-AS1: A functional cancer-related long non-coding RNA

Long non-coding RNAs (lncRNAs) regulate gene expression and carcinogenesis. The lncRNA heart and neural crest derivatives expressed transcript 2 antisense RNA 1 (HAND2‑AS1) suppresses tumor growth, and its expression level was lower in tumor tissues than in adjacent normal tissues of most types of human cancers, including non-small cell lung cancer, ovarian cancer, breast cancer, gastric cancer, colorectal cancer, cervical cancer, endometrial cancer, prostate cancer, and esophagus squamous cell carcinoma. However, one study reported that the HAND2‑AS1 expression was upregulated in hepatocellular carcinoma tissues comparing with non-tumor tissues and it promoted tumor development. The aberrant expression of HAND2-AS1 was strongly linked to tumor progression and prognosis. Moreover, HAND2-AS1 was involved in tumor cell proliferation, differentiation, apoptosis, and cellular glucose metabolism. This review summarizes data on the expression profile, functions, underlying mechanism, and clinical value of HAND2-AS1 in cancer. The expression profile of HAND2-AS1 in 33 tumors was evaluated by bioinformatics analysis of The Cancer Genome Atlas.

Circular RNA circ_0079593 enhances malignant melanoma progression by the regulation of the miR-573/ABHD2 axis

BACKGROUND

Malignant melanoma is the most fatal type of skin tumor. Circular RNAs (circRNAs) have been implicated in the malignant progression of melanoma.

OBJECTIVE

The main purpose of this paper was to identify the precise parts of circ_0079593 in the malignant progression of melanoma.

METHODS

The levels of circ_0079593, miR-573 and abhydrolase domain containing 2 (ABHD2) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Cell proliferation, colony formation, cell cycle progression, apoptosis, migration, and invasion were evaluated using the Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, and transwell assays, respectively. Targeted correlations among circ_0079593, miR-573 and ABHD2 were confirmed by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. Animal studies were performed to assess the role of circ_0079593 in vivo.

RESULTS

Our data showed that circ_0079593 level was up-regulated in melanoma tissues and cells. The knockdown of circ_0079593 suppressed cell proliferation, cell cycle progression, migration, invasion, and enhanced apoptosis in vitro and inhibited tumor growth in vivo. Mechanistically, circ_0079593 directly targeted miR-573, and circ_0079593 controlled ABHD2 expression by miR-573. MiR-573 mediated the regulation of circ_0079593 on melanoma cell progression in vitro. Moreover, ABHD2 was a functional target of miR-573 in regulating melanoma cell progression in vitro.

CONCLUSION

Our findings identified that the knockdown of circ_0079593 suppressed melanoma progression at least partially through targeting the miR-573/ABHD2 axis, providing evidence for developing circ_0079593 as a promising therapeutic target for melanoma treatment.

lncRNA FLVCR1‑AS1 drives colorectal cancer progression via modulation of the miR‑381/RAP2A axis

Colorectal cancer (CRC) is one of the most prevalent types of cancer globally. Long non‑coding RNAs (lncRNAs) have been suggested to serve as vital regulators in CRC. lncRNA feline leukemia virus subgroup C receptor 1 antisense RNA 1 (FLVCR1‑AS1) is closely associated with the tumorigenesis of various types of cancer. The aim of the present study was to investigate the molecular mechanisms of lncRNA FLVCR1‑AS1 in CRC progression. The expression levels of FLVCR1‑AS1, microRNA (miR)‑381 and Ras‑related protein 2a (RAP2A) were measured by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). A Kaplan‑Meier analysis was performed to determine the overall survival rate of patients with CRC. Furthermore, cell viability, migration and invasion were assessed using Cell Counting Kit‑8 (CCK‑8) and Transwell assays. The interaction between genes was confirmed using dual‑luciferase reporter and pull‑down assays. The results demonstrated that FLVCR1‑AS1 was upregulated in CRC tissues and cells, and increased FLVCR1‑AS1 expression levels in patients with CRC were associated with poor prognosis. FLVCR1‑AS1 knockdown significantly attenuated the viability, migration and invasion ability of CRC cells. In addition, the results confirmed that FLVCR1‑AS1 directly binds with miR‑381‑3p, and that RAP2A is a direct target of miR‑381‑3p. The overexpression of FLVCR1‑AS1 increased RAP2A expression levels. Functional assays revealed that miR‑381 inhibitor or RAP2A overexpression attenuated the suppressive effects of FLVCR1‑AS1 silencing on CRC cell viability, migration and invasion. Overall, the findings of the current study suggest that FLVCR1‑AS1 promotes CRC progression via the miR‑381/RAP2A pathway. These findings may provide a novel approach for CRC treatment.

miR-573 suppresses pancreatic cancer cell proliferation, migration, and invasion through targeting TSPAN1

PURPOSE

To explore whether miR-573 can suppress pancreatic cancer cell proliferation, migration, and invasion by targeting TSPAN1.

METHODS

The expression of miR-573 and TSPAN1 in pancreatic cancer tissues and cells lines was analyzed using RT-qPCR. The human pancreatic cancer cell line PANC‑1 was transfected with miR-573 mimic, pcDNA3.1-TSPAN1, or genOFFTM st-h-TSPAN1. The effects of miR-573 and TSPAN1 on cell proliferation, colony formation, migration, and invasion were analyzed by CCK‑8, colony formation, transwell migration, and invasion assay, respectively. Target genes of miR-573 were screened using bioinformatics tools and confirmed by dual-luciferase reporter assay and real-time PCR. The effects of miR-573 in vivo were observed using tumor xenografts.

RESULTS

We found that miR-573 is downregulated and TSPAN1 is upregulated in pancreatic cancer tissues and cells lines. Function assays demonstrated that overexpression of miR-573 inhibited cell proliferation, colony formation, migration, and invasion of pancreatic cancer cells, as well as suppressing tumor growth in vivo. Target genes of miR-573 were predicted using bioinformatics tools and confirmed by dual-luciferase reporter assay and RT-qPCR or western blotting. Downregulation of TSPAN1 also inhibited cell proliferation, colony formation, migration, and invasion of pancreatic cancer cells. Furthermore, overexpression of TSPAN1 attenuated miR-573-induced inhibition of pancreatic cancer cell proliferation and migration.

CONCLUSION

Our findings indicated that miR-573 suppresses pancreatic cancer cell proliferation, migration, and invasion through targeting TSPAN1. TSPAN1 targeted by miR-573 might be a potential therapeutic target for clinical treatment of pancreatic cancer.

Circ_0016760 Acts as a Sponge of MicroRNA-4295 to Enhance E2F Transcription Factor 3 Expression and Facilitates Cell Proliferation and Glycolysis in Nonsmall Cell Lung Cancer

Background: Circular RNAs (circRNAs) have been validated as important regulators of nonsmall cell lung cancer (NSCLC), but the role and potential mechanism of circ_0016760 in NSCLC remain largely unclear. Materials and Methods: Quantitative real-time polymerase chain reaction was performed to detect the levels of circ_0016760, microRNA-4295 (miR-4295), and E2F transcription factor 3 (E2F3). The cell proliferation was measured by methyl-thiazolyl diphenyl-tetrazolium bromide assay. The protein levels of proliferating cell nuclear antigen and E2F3 were examined by Western blot. Xenograft mice model was constructed to explore the effect of circ_0016760 on tumor growth in vivo. The relationship among circ_0016760, miR-4295, and E2F3 was evaluated using dual-luciferase reporter assay. Glucose consumption of NSCLC cells was assessed by the glucose assay kit. Results: Circ_0016760 and E2F3 expression levels were upregulated in NSCLC tissues and cells, while miR-4295 was downregulated. Circ_0016760 could bind to miR-4295, and negatively modulate its expression in NSCLC cells. Besides, miR-4295 directly targeted E2F3 and inversely regulated E2F3 expression. More importantly, Circ_0016760 facilitated proliferation and glycolysis of NSCLC cells by increasing E2F3 by sponging miR-4295 as well as promoted the tumor growth in vivo. Conclusion: Circ_0016760 served as a growth-promoting circRNA in NSCLC by facilitating cell proliferation and glycolysis by regulating the miR-4295/E2F3 axis, providing a novel potential target for NSCLC treatment.

LncRNA OIP5-AS1 promotes the malignancy of pancreatic ductal adenocarcinoma via regulating miR-429/FOXD1/ERK pathway

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC), a subtype of pancreatic cancer, is a malignant tumor with unfavorable prognosis. Despite accumulating researches have made efforts on finding novel therapeutic methods for this disease, the underlying mechanism of long non-coding RNAs (lncRNAs) remains elusive. OIP5 antisense RNA 1 (OIP5-AS1) has been reported to play important role in the occurrence and development of multiple human cancers. This study was aimed at unveiling the regulatory role of OIP5-AS1 in PDAC.

METHODS

RT-qPCR analysis revealed the OIP5-AS1 expression in PDAC tissues and adjacent normal ones. Kaplan-Meier method was applied to analyze the overall survival of patients with high or low level of OIP5-AS1. Gain- or loss-of function assays were performed to assess the effects of OIP5-AS1 knockdown on cell functions, including proliferation, migration and EMT process. Mechanism experiments, such as luciferase reporter and RNA pull-down assays proved the interaction between OIP5-AS1 and miR-429 as well as that between miR-429 and FOXD1.

RESULTS

OIP5-AS1 was up-regulated in PDAC tissues and cell lines, and high level of OIP5-AS1 indicated poor prognosis in PDAC patients. OIP5-AS1 knockdown hindered cell proliferation, migration and epithelial-mesenchymal transition (EMT) process, while overexpression of OIP5-AS1 caused the opposite results. OIP5-AS1 activated ERK pathway through up-regulating forkhead box D1 (FOXD1) expression by sponging miR-429. Furthermore, OIP5-AS1 facilitated cell growth in vivo.

CONCLUSION

OIP5-AS1 exerted oncogenic function in PDAC cells through targeting miR-429/FOXD1/ERK pathway.

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.

Roles of Wnt/β-Catenin Signaling Pathway Regulatory Long Non-Coding RNAs in the Pathogenesis of Non-Small Cell Lung Cancer

Lung cancer is one of the leading causes of cancer-related mortality worldwide. Non-small cell lung cancer (NSCLC) is the most common pathological type of lung cancer. Long non-coding RNAs (lncRNAs) are promising novel diagnostic and prognostic biomarkers, as well as potential therapeutic targets for lung cancer. Long non-coding RNAs (lncRNAs) have been demonstrated to modulate tumor cells proliferation, cell cycle progression, invasion, and metastasis by regulating gene expression at transcriptional, post-transcriptional, and epigenetic levels. The oncogenic aberrant Wnt/β-catenin signaling is prominent in lung cancer, playing a vital role in tumorigenesis, prognosis, and resistance to therapy. Interestingly, compelling studies have demonstrated that lncRNAs exert either oncogenic or tumor suppressor roles by regulating Wnt/β-catenin signaling. In this review, we aim to present the current accumulated knowledge regarding the roles of Wnt/β-catenin signaling-regulated lncRNAs in the pathogenesis of non-small cell lung cancer (NSCLC). Better understanding of the effects of lncRNAs on Wnt/β-catenin signaling might contribute to the improved understanding of the molecular tumor pathogenesis and to the uncovering of novel therapeutic targets in NSCLC.

Knockdown SNHG20 Suppresses Nonsmall Cell Lung Cancer Development by Repressing Proliferation, Migration and Invasion, and Inducing Apoptosis by Regulating miR-2467-3p/E2F3

Background: Lung cancer was one of the most common malignant tumors worldwide. In China, lung cancer has become the leading reason of malignant tumors-related mortality in urban population, whereas nonsmall cell lung cancer (NSCLC) represented at least 80% of all lung cancers with poor 5-year survival rate. Long noncoding RNA (lncRNA) small nucleolar RNA host gene 20 (SNHG20) was reported to be associated with NSCLC, but the regulatory mechanisms of SNHG20 in NSCLC needed further investigation. Methods: The abundances of SNHG20 and E2F transcription factor 3 (E2F3) in NSCLC tissues and cells were measured with real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot assays. 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT) was applied to detect cells proliferation, whereas flow cytometry analysis was used to monitor cell apoptosis. In addition, cells capabilities of migratory and invasion were assessed with transwell assay. The association among miR-2467-3p, SNHG20, and E2F3 was analyzed by dual-luciferase reporter assay. The related protein expression levels were determined by Western blot. Results: SNHG20 and E2F3 was upregulation in NSCLC tissues and cell lines. Mechanical experiment displayed that knockdown of SNHG20 or E2F3 silencing could inhibit proliferation, motility, and improve apoptosis in NSCLC cell lines. Restored expression of E2F3 could effectively reverse reduction of proliferation, motility, and promotion of apoptosis caused by SNHG20 silencing in NSCLC cells. Besides, SNHG20 activated protein kinase B (AKT) signaling pathway and increased E2F3 level in NSCLC cells through targeting miR-2467-3p. Conclusion: SNHG20 contributed to NSCLC development through mediating AKT signaling pathway and sponging miR-2467-3p to elevate E2F3 expression in NSCLC cells.

Long non‑coding RNA FLVCR1‑AS1 promotes glioma cell proliferation and invasion by negatively regulating miR‑30b‑3p

Glioblastoma (GBM) is the most common and malignant primary brain tumor in adults that originates from glial cells. The prognosis of patients with high‑grade glioma is poor. It is therefore crucial to develop effective therapeutic strategies. Long non‑coding RNAs (lncRNAs) have been reported as potential inducers or suppressors of tumor progression. Previous studies have indicated that the lncRNA Feline Leukemia Virus Subgroup C Cellular Receptor 1 Antisense RNA 1 (FLVCR1‑AS1) is involved in the development and progression of gastric and lung cancer, as well as hepatocellular carcinoma and cholangiocarcinoma; however, the biological effect of FLVCR1‑AS1 in glioma is not completely understood. The aim of the present study was to investigate how FLVCR1‑AS1 modulates cell proliferation and invasion in glioma. FLVCR1‑AS1 expression was significantly upregulated in GBM tissues compared with adjacent normal brain samples, and was higher in GBM cell lines compared with normal human astrocyte cells. Furthermore, the microRNA (miR)‑30b‑3p was revealed to be a putative target of FLVCR1‑AS1, and the suppressive effects of miR‑30b‑3p on cellular proliferation and invasion were reversed following FLVCR1‑AS1‑knockdown. The results from Cell Counting Kit‑8 and Transwell assays confirmed that FLVCR1‑AS1‑knockdown inhibited GBM cell proliferation and invasion ability. In addition, FLVCR1‑AS1 was found to directly interact with miR‑30b‑3p, and a rescue experiment further established that FLVCR1‑AS1 contributed to glioma progression by inhibiting miR‑30b‑3p. The results from the present study demonstrated that FLVCR1‑AS1 may serve an oncogenic role in GBM and promote disease progression by interacting with miR‑30b‑3p. These findings suggested that FLVCR1‑AS1 may be considered as a novel therapeutic target and diagnostic biomarker for GBM.

Downregulation of LINC00665 confers decreased cell proliferation and invasion via the miR-138-5p/E2F3 signaling pathway in NSCLC

Non-small cell lung cancer (NSCLC) is a type of malignant tumor which threatens human health and life. Recently, some researches on long non-coding RNAs (lncRNAs) in NSCLC has elucidated critical regulatory roles in cell proliferation, migration, and invasion, the relative clinical significance and mechanisms of action are still unclear. This study focuses on the important role of a novel lncRNA LINC00665 in the development of NSCLC. Long intergenic non-protein coding RNA 665 gene (LINC00665) was found through microarray analysis and was measured by real-time quantitative PCR (RT-qPCR). The interactions between LINC00665 and miR-138-5p as well as the interactions between miR-138-5p and E2F3 (E2F transcription factor 3) were explored by bioinformatics analysis and dual-luciferase assays. CCK-8, transwell and mouse xenograft assays were performed to investigate the effects of LINC00665 and miR-138-5p on NSCLC proliferation and invasion. As a result, LINC00665 expression was upregulated in NSCLC lung tissues and cells. Downregulated LINC00665 could arrest A549 and H1299 cell proliferation and invasion in vitro, and this finding was recapitulated in vivo. LINC00665 directly regulated the expression of miR-138-5p. Additionally, E2F3 was one of the targets of miR-138-5p; E2F3 without 3'UTR could reverse the inhibitory effects of downregulated LINC00665 on proliferation and invasion in A549 and H1299 cells. In conclusion, dysregulation of LINC00665 plays a vital role in NSCLC progression, indicating that its downregulation may confer decreased cell proliferation and invasion via the miR-138-5p/E2F3 signaling pathway.

Long non-coding RNA LINC00858 exerts a tumor-promoting role in colon cancer via HNF4α and WNK2 regulation

BACKGROUND

Long non-coding RNAs (lncRNAs) are known to be frequently dysregulated in many types of human cancer. As yet, however, their roles in colon carcinogenesis have not been fully elucidated. In the current study, we assessed whether lncRNA LINC00858 may be involved in the progression of colon cancer and, in addition, investigated its downstream targets.

METHODS

LINC00858 expression in patient-derived colon cancer tissues and in colon cancer cell lines was determined using RT-qPCR. Also, relationships between LINC00858 expression and various clinicopathological characteristics were analyzed. The subcellular localization of LINC00858 was determined using fluorescence in situ hybridization. Interactions between LINC00858 and its downstream targets were first predicted by bioinformatic analysis and, subsequently, confirmed by RNA pull-down, RNA immunoprecipitation, chromatin immunoprecipitation and dual luciferase reporter assays. After in vitro upregulation of LINC00858 and/or silencing of WNK2 and hepatocyte nuclear factor 4α (HNF4α), the biological behavior of colon cancer cells was assessed using 5-ethynyl-2'-deoxyuridine (EdU) incorporation, Transwell invasion and tube formation assays. In vivo cancer growth was evaluated in nude mice.

RESULTS

We found that LINC00858 was highly expressed in primary colon cancer tissues and colon cancer cell lines, and was mainly located in the nucleus. High LINC00858 expression was found to correlate with a poor differentiation, advanced TNM stages and lymph node metastasis. Exogenous overexpression of LINC00858 promoted cell proliferation, invasion and migration of colon cancer cells, and facilitated angiogenesis and tumor growth. In addition, we found that LINC00858 can bind to and upregulate the nuclear transcription factor HNF4α, leading to WNK2 expression downregulation. This, in turn, resulted in the promotion of colon cancer cell growth.

CONCLUSIONS

From our data we conclude that LINC00858 acts as a tumor-promoting lncRNA in colon cancer by upregulating HNF4α and downregulating WNK2. Our results may provide novel targets for the treatment for colon cancer.

Down-regulation of MBNL1-AS1 contributes to tumorigenesis of NSCLC via sponging miR-135a-5p

Lung cancer remains a big threat to human health. Growing evidence has reported the crucial regulatory effect of lncRNAs on NSCLC progression. Nevertheless, the detailed function of lncRNA MBNL1-AS1 involved in NSCLC development is poorly known. In our research, we confirmed that MBNL1-AS1 was significantly reduced in NSCLC patient tissues and NSCLC cells. Meanwhile, we reported that overexpression of MBNL1-AS1 obviously repressed A549 and H1975 cell proliferation, blocked cell cycle and inhibited the migration and invasion. Moreover, A549 and H1975 cell apoptosis was increased by the overexpression of MBNL1-AS1. Then, we predicted that miR-135a-5p was a potential target of MBNL1-AS1 and its level was correlated with MBNL1-AS1 in NSCLC negatively. Our previous study indicated miR-135a-5p could induce lung cancer progression through regulating LOXL4. Here, we found that MBNL1-AS1 was able to regulate miR-135a-5p expression negatively. The direct binding association between MBNL1-AS1 and miR-135a-5p was proved using dual-luciferase reporter assay and RIP experiment. Subcutaneous xenotransplanted tumor model was set up and it was confirmed increased MBNL1-AS1 remarkably restrained tumorigenic ability of NSCLC through sponging miR-135a-5p in vivo. To sum up, our data revealed the significance of the MBNL1-AS1 and miR-135a-5p in NSCLC. In conclusion, MBNL1-AS1 could be a new therapeutic target to treat NSCLC.

Long noncoding RNA FLVCR1-AS1 aggravates biological behaviors of glioma cells via targeting miR-4731-5p/E2F2 axis

Long noncoding RNAs (lncRNAs) display essential roles in cancer progression. FLVCR1-AS1 is a rarely investigated lncRNAs involved in various human cancers, such as hepatocellular carcinoma and lung cancer. However, its function in glioma has not been clarified. In our study, we found that FLVCR1-AS1 was highly expressed in glioma tissues and cell lines. And upregulation of FLVCR1-AS1 predicted poor prognosis in patients with glioma. Moreover, FLVCR1-AS1 knockdown inhibited proliferation, migration and invasion of glioma cells. Through bioinformatics analysis, we identified that FLVCR1-AS1 was a sponge for miR-4731-5p to upregulate E2F2 expression. Moreover, rescue assays indicated that FLVCR1-AS1 modulated E2F2 expression to participate in glioma progression. Altogether, our research demonstrates that the FLVCR1-AS1/miR-4731-5p/E2F2 axis is a novel signaling in glioma and may be a potential target for tumor therapy.

Long noncoding RNA SBF2-AS1 act as a ceRNA to modulate cell proliferation via binding with miR-188-5p in acute myeloid leukemia

LncRNA SBF2-AS1 has been reported to be implicated in the deterioration of multiple human cancers. However, the roles and underlying mechanisms of SBF2-AS1 in acute myeloid leukemia (AML) are still unclear. In the present study, the online GEPIA database showed that SBF2-AS1 expression was significantly increased in AML samples. QRT-PCR results showed that SBF2-AS1 expression was upregulated in AML cells. CCK-8 assay revealed that SBF2-AS1 inhibition decreased AML cells proliferation ability in vitro. Flow cytometry assays showed that SBF2-AS1 inhibition induced AML cells apoptosis and arrested AML cells in G0/G1 phase. Mechanistically, miR-188-5p was identified as a direct target of SBF2-AS1. SBF2-AS1 upregulated the expression level of ZFP91 by sponging miR-188-5p. And the effects of SBF2-AS1 suppression on AML cells progression could be abolished by miR-188-5p inhibitors. Moreover, we found that SBF2-AS1 inhibition reduced tumor growth in vivo. Taken together, our findings elucidated that SBF2-AS1 could act as a miRNA sponge in AML progression, and provided a potential therapeutic strategy for AML treatment.

LncRNA FLVCR1-AS1 mediates miR-513/YAP1 signaling to promote cell progression, migration, invasion and EMT process in ovarian cancer

Background

Long noncoding RNAs (lncRNAs) have been reported to be associated with the proliferation of several cancer cells. The aim of this study was to investigate the role of FLVCR1-AS1 in ovarian serous cancer (OSC).

Methods

FLVCR1-AS1 expression was determined in human OSC tissues, serums and cell lines. The role of FLVCR1-AS1 knockdown or overexpression on OSC cell growth, migration, invasion, apoptosis and epithelial to mesenchymal transition (EMT) were evaluated in vitro using CCK8, colony formation assay, wound healing assay, transwell assay and western blot assay. Besides, luciferase reporter assays were performed to identify interactions among FLVCR1-AS1 and its target genes. Moreover, the in vivo effects were investigated using immunocompromised NSG female mice.

Results

In this study, FLVCR1-AS1 expression was upregulated in OSC tissues, serums, and cells. Knockdown FLVCR1-AS1 decreased cell growth, migration, invasion, and EMT, as well as increased apoptosis in OSC cells, whereas, overexpression of FLVCR1-AS1 increased cell proliferation, migration, invasion, and EMT, and decreased apoptosis of OSC cells. Besides, FLVCR1-AS1 directly bound to miR-513 and downregulated its expression. Moreover, FLVCR1-AS1 reversed the effect of miR-513 on the OSC cell growth, which might be associated with the role of YAP1. Furthermore, in terms of mechanism, FLVCR1-AS1 promoted EMT in OSC cells. Finally, mice models further confirmed that knockdown FLVCR1-AS1 distinctly suppressed cell growth and EMT in vivo.

Conclusion

Taken together, FLVCR1-AS1 mediated miR-513/YAP1 signaling to promote cell progression, migration, invasion and EMT process in OSC cells.

lncRNA PDIA3P regulates cell proliferation and invasion in non-small cell lung cancer

Increasing evidence has shown that long non-coding RNAs (lncRNAs) serve a critical role in tumor progression. The lncRNA protein disulfide isomerase family A member 3 pseudogene 1 (PDIA3P) is associated with the progression of oral squamous cell carcinoma and multiple myeloma. However, the roles of lncRNA PDIA3P in non-small cell lung cancer (NSCLC) remain unknown. In the present study, it was demonstrated that lncRNA PDIAP3 expression was significantly increased in patients with NSCLC, particularly in patients with an advanced Tumor-Node-Metastasis stages and lymph-node metastasis. The Gene Expression Profiling Interactive Analysis database revealed that patients with NSCLC with high lncRNA PDIA3P expression had a poorer disease-free survival rate. Furthermore, functional assays suggested that PDIA3P inhibition significantly suppressed the proliferation and invasion of NSCLC cells in vitro and reduced tumor growth in vivo. In addition, lncRNA PDIA3P enhanced the activity of the Wnt/β-catenin pathway in progression of NSCLC. The present study showed that lncRNA PDIA3P promoted NSCLC progression by regulating Wnt/β-catenin signaling, highlighting a potential therapeutic target for treating patients with NSCLC treatment.

Involvement of the long noncoding RNA NEAT1 in carcinogenesis

Altered expression levels of the long noncoding RNA (lncRNA) nuclear‐enriched abundant transcript 1 (NEAT1) have been reported in different types of cancer. More than half of the NEAT1 studies in cancer have been published within the last 2 years. In this review, we discuss very recent developments and insights into NEAT1 contribution to carcinogenesis. Summarizing the literature, it becomes obvious that NEAT1 is a lncRNA highly de‐/upregulated in a variety of cancer entities, in which it primarily acts as a competing endogenous RNA (ceRNA) which sponges tumor‐suppressive microRNA (miRNA). The sponged miRNA lose their ability to degrade, silence, or hamper translation of their downstream—mostly oncogenic—target transcripts, ultimately promoting carcinogenesis. This role of NEAT1 function in tumorigenesis suggests it may be a prognostic biomarker as well as potential therapeutic target, pending the completion of further studies into the underlying mechanisms.