LncRNA LINC00520 aggravates cell proliferation and migration in lung adenocarcinoma via a positive feedback loop

Non-coding RNA-directed therapeutics in lung cancer: Delivery technologies and clinical applications

Lung cancer is one of the most aggressive and deadliest health threats. There has been an increasing interest in non-coding RNA (ncRNA) recently, especially in the areas of carcinogenesis and tumour progression. However, ncRNA-directed therapies are still encountering obstacles on their way to the clinic. In the present article, we provide an overview on the potential of targeting ncRNA in the treatment of lung cancer. Then, we discuss the delivery challenges and recent approaches enabling the delivery of ncRNA-directed therapies to the lung cancer cells, where we illuminate some advanced technologies including chemically-modified oligonucleotides, nuclear targeting, and three-dimensional in vitro models. Furthermore, advanced non-viral delivery systems recruiting nanoparticles, biomimetic delivery systems, and extracellular vesicles are also highlighted. Lastly, the challenges limiting the clinical trials on the therapeutic targeting of ncRNAs in lung cancer and future directions to tackle them are explored.

Circular RNA Circ_0005962 Contributes to Lung Adenocarcinoma Cell Proliferation and Stem Cell Formation Through Sponging of miR-3611 and Modulating CYP24A1 Expression

Recently, several studies have revealed that circular RNAs (circRNAs) play significant roles in various tumors, including lung adenocarcinoma (LUAD). Furthermore, it has been reported that circ_0005962 was upregulated in LUAD cells. Accordingly, this research is designed to investigate the mechanism of circ_0005962 on LUAD development. Circ_0005962, microRNA-3611 (miR-3611), and Cytochrome P450 family 24 subfamily A member 1 (CYP24A1) level were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation ability, cell cycle progression, and sphere formation ability were detected using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), Colony formation, flow cytometry, and sphere formation assay. Protein levels of proliferating cell nuclear antigen (PCNA), Ki67, NANOG, CD133, OCT4, and CYP24A1 were determined using Western blot assay. Using bioinformatics software (Starbase3.0 and TargetScan), the binding between miR-3611 and circ_0005962 or CYP24A1 was predicted and proved using RNA Immunoprecipitation (RIP) and RNA pull-down assays. A xenograft tumor model in vivo was used to analyze the biological role of circ_0005962 on LUAD cell growth. Increased circ_0005962 and CYP24A1, and reduced miR-3611 were observed in LUAD tissues and cell lines. Functional assays testified that circ_0005962 depletion might hinder LUAD cell proliferation and sphere formation capability, but induced cell apoptosis in vitro. Molecular mechanism experiments exhibited that circ_0005962 served as a miR-3611 sponge and mediated CYP24A1 content by absorbing miR-3611. Additionally, silencing of circ_0005962 inhibited tumor growth in xenograft modes. Together, circ_0005962 was overexpressed in LUAD, and its deficiency repressed LUAD progression via targeting the miR-3611/ CYP24A1 axis, providing a novel mechanism for understanding the development of LUAD.

A novel prognostic signature for lung adenocarcinoma based on cuproptosis-related lncRNAs: A Review

Lung adenocarcinoma (LUAD) is a highly heterogeneous disease with complex pathogenesis, high mortality, and poor prognosis. Cuproptosis is a new type of programmed cell death triggered by copper accumulation that may play an important role in cancer. LncRNAs are becoming valuable prognostic factors in cancer patients. The effect of cuproptosis-related lncRNAs (CRlncRNAs) on LUAD has not been clarified. Based on the Cancer Genome Atlas database, CRlncRNAs were screened by co-expression analysis of cuproptosis- related genes and lncRNAs. Using CRlncRNAs, Cox and LASSO regression analyses constructed a risk prognostic model. The predictive efficacy of the model was assessed and validated using survival analysis, receiver operating characteristic curve, univariate and multifactor Cox regression analysis, and principal component analysis. A nomogram was constructed and calibration curves were applied to enhance the predictive efficacy of the model. Tumor Mutational Burden analysis and chemotherapeutic drug sensitivity prediction were performed to assess the clinical feasibility of the risk model. The novel prognostic signature consisted of 5 potentially high-risk CRlncRNAs, MAP3K20-AS1, CRIM1-DT, AC006213.3, AC008035.1, and NR2F2-AS1, and 5 potentially protective CRlncRNAs, AC090948.1, AL356481.1, AC011477.2, AL031600.2, and AC026355.2, which had accurate and robust predictive power for LUAD patients. Collectively, the novel prognostic signature constructed based on CRlncRNAs can effectively assess and predict the prognosis of patients and provide a new perspective for the diagnosis and treatment of LUAD.

The Role of FOXP3 on Tumor Metastasis and Its Interaction with Traditional Chinese Medicine

Forkhead box protein 3 (FOXP3) is an important transcription factor for regulatory T cells (Tregs) and plays an important role in their immunosuppressive function. In recent years, studies have found that FOXP3 is expressed in many kinds of tumors and plays different roles in tumors' biological behaviors, including tumor proliferation, metastasis, drug resistance, and prognosis. However, the effects of FOXP3 on tumor metastasis and its interaction with traditional Chinese medicine (TCM) remain unclear. Therefore, in this review, we focus on the effects of FOXP3 on tumor metastasis and its relationship with TCM, which can provide evidence for further research and therapy in clinical settings.

N6-methyladenosine-mediated upregulation of LINC00520 accelerates breast cancer progression via regulating miR-577/POSTN axis and downstream ILK/AKT/mTOR signaling pathway

Various lncRNAs have been reported to be closely associated with cancer initiation and progression in breast cancer (BC), including LINC00520. However, the role and underlying mechanisms by which LINC00520 affects BC aggressiveness have not been fully delineated, and this study aimed to explore this issue. Through performing qRT-PCR analysis, we proved that LINC00520 was significantly upregulated in BC tissues and cells, compared with normal tissues and cells. Higher expression of LINC00520 was closely related to higher tumor grade, poor differentiation and shorter survival in BC patients. Next, the loss-of-function experiments evidenced that silencing LINC00520 suppressed BC cell proliferation, migration and epithelial-mesenchymal transition (EMT) in vitro, and inhibited tumorigenesis in vivo. Interestingly, we found that LINC00520 expression was positively regulated by METTL3-mediated N6-methyladenosine(m⁶A) modification in BC. Furthermore, we identified the tumor-suppressor miR-577 as the binding target of LINC00520 in BC. Mechanistically, LINC00520 elevated POSTN level via sponging miR-577, resulting in the activation of the downstream tumor-promoting ILK/Akt/mTOR pathway. Finally, the rescuing experiments evidenced that both POSTN knockdown and ILK/Akt/mTOR pathway inhibitor OSU-T315 abrogated the promoting effects of miR-577 ablation on the malignant phenotypes in BC. Collectively, this study firstly verified that LINC00520 acted as a ceRNA of miR-577 to advance BC aggressiveness in a m⁶A-dependent manner, providing novel biomarkers for BC diagnosis and therapy.

Long non-coding RNAs and exosomal lncRNAs: Potential functions in lung cancer progression, drug resistance and tumor microenvironment remodeling

Among the different kinds of tumors threatening human life, lung cancer is one that is commonly observed in both males and females. The aggressive behavior of lung cancer and interactions occurring in tumor microenvironment enhances the malignancy of this tumor. The lung tumor cells have demonstrated capacity in developing chemo- and radio-resistance. LncRNAs are a category of non-coding RNAs that do not encode proteins, but their aberrant expression is responsible for tumor development, especially lung cancer. In the present review, we focus on both lncRNAs and exosomal lncRNAs in lung cancer, and their ability in regulating proliferation and metastasis. Cell cycle progression and molecular mechanisms related to lung cancer metastasis such as EMT and MMPs are regulated by lncRNAs. LncRNAs interact with miRNAs, STAT, Wnt, EZH2, PTEN and PI3K/Akt signaling pathways to affect progression of lung cancer cells. LncRNAs demonstrate both tumor-suppressor and tumor-promoting functions in lung cancer. They can be considered as biomarkers in lung cancer and especially exosomal lncRNAs present in body fluids are potential tools for minimally invasive diagnosis. Furthermore, we discuss regulation of lncRNAs by anti-cancer drugs and genetic tools as well as the role of these factors in therapy response of lung cancer cells.

Down-regulated NEDD4L facilitates tumor progression through activating Notch signaling in lung adenocarcinoma

Neural precursor cell expressed developmentally down-regulated 4-like protein (NEDD4L), an E3 ubiquitin ligase, exerts an important role in diverse biological processes including development, tumorigenesis, and tumor progression. Although the role of NEDD4L in the pathogenesis of lung adenocarcinoma (LUAD) has been described, the mechanism by which NEDD4L promotes LUAD progression remains poorly understood. In the study, the correlation between NEDD4L level and clinical outcome in LUAD patients was analysed using the data from The Cancer Genome Atlas (TCGA) database. NEDD4L expression in LUAD cell lines and tissue samples was assessed through quantitative real-time PCR (qRT-PCR). The biological function of NEDD4L on regulating LUAD cell proliferation was tested with Cell Counting Kit-8 (CCK-8) assay in vitro, and mouse xenograft tumor model in vivo. We found that NEDD4L expression was significantly decreased in LUAD tissues and cell lines. Lower expression of NEDD4L exhibited a significantly poorer overall survival. Functionally, NEDD4L knockdown in H1299 cells accelerated cell growth, whereas NEDD4L overexpression in A549 cells repressed cell proliferation. NEDD4L overexpression also inhibited tumor xenograft growth in vivo. Mechanistically, NEDD4L decreased the protein stability of notch receptor 2 (Notch2) through facilitating its ubiquitination and degradation by ubiquitin-proteasome system. Consequently, NEDD4L negatively regulated Notch signaling activation in LUAD cells, and RO4929097 (a Notch inhibitor) treatment effectively repressed the effect of NEDD4L knockdown on LUAD cell proliferation. Taken together, these results demonstrate that down-regulated NEDD4L facilitates LUAD progression by activating Notch signaling, and NEDD4L may be a promising target to treat LUAD.

LINC00520: A Potential Diagnostic and Prognostic Biomarker in Cancer

Long non-coding RNA (lncRNA) is important in the study of cancer mechanisms. LINC00520 is located on human chromosome 14q22.3 and is a highly conserved long non-coding RNA. LINC00520 is widely expressed in various tissues. The expression of LINC00520 is regulated by transcription factors such as Sp1, TFAP4, and STAT3. The high expression of LINC00520 is significantly related to the risk of 11 cancers. LINC00520 can competitively bind 10 miRNAs to promote tumor cell proliferation, invasion, and migration. In addition, LINC00520 is involved in the regulation of P13K/AKT and JAK/STAT signaling pathways. The expression of LINC00520 is significantly related to the clinicopathological characteristics and prognosis of tumor patients and is also related to the sensitivity of HNSCC to radiotherapy. Here, this article summarizes the abnormal expression pattern of LINC00520 in cancer and its potential molecular regulation mechanism and points out that LINC00520 can be used as a potential biomarker for cancer diagnosis, prognosis, and treatment.

LINC00520 up-regulates SOX5 to promote cell proliferation and invasion by miR-4516 in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common human cancers. Long non-coding RNA (lncRNA) has been demonstrated to play an important role in regulating tumor development. The current study aims to explore the specific role of LINC00520 during HCC progression. The present study identified that LINC00520 was upregulated in HCC tissues and indicated poor patient survival. Overexpression of LINC00520 promoted HCC cell proliferation, migration and invasion, while LINC00520 downregulation led to the opposite effects. Besides, LINC00520 knockdown was found to inhibit tumor growth in vivo. Furthermore, LINC00520 acted as a sponge of miR-4516 to regulate SRY-related high mobility group box 5 (SOX5). In addition, the inhibition of miR-4516 partly reversed the inhibitory effect of LINC00520 silencing on HCC cell proliferation, migration and invasion. In conclusion, the inhibition of LINC00520 suppressed HCC cell proliferation, migration and invasion through mediating miR-4516/SOX5 axis. Therefore, our study provides a basis for the development of treatment strategies for HCC.