Long non-coding RNA NEAT1 promotes non-small cell lung cancer progression through regulation of miR-377-3p-E2F3 pathway

Extracellular vesicles (EVs), a class of heterogeneous membrane vesicles, are generally divided into exosomes and microvesicles on basis of their origination from the endosomal membrane or the plasma membrane, respectively. EV-mediated bidirectional communication among various cell types supports cancer cell growth and metastasis. EVs derived from different cell types and status have been shown to have distinct RNA profiles, comprising messenger RNAs and non-coding RNAs (ncRNAs). Recently, ncRNAs have attracted great interests in the field of EV-RNA research, and growing numbers of ncRNAs ranging from microRNAs to long ncRNAs have been investigated to reveal their specific functions and underlying mechanisms in the tumor microenvironment and premetastatic niches. Emerging evidence has indicated that EV-RNAs are essential functional cargoes in modulating hallmarks of cancers and in reciprocal crosstalk within tumor cells and between tumor and stromal cells over short and long distance, thereby regulating the initiation, development and progression of cancers. In this review, we discuss current findings regarding EV biogenesis, release and interaction with target cells as well as EV-RNA sorting, and highlight biological roles and molecular mechanisms of EV-ncRNAs in cancer biology.

Long noncoding RNAs (lncRNAs) play crucial roles in carcinogenesis. However, the function and mechanism of lncRNAs in human non–small-cell lung cancer (NSCLC) are still remaining largely unknown. Long intergenic noncoding RNA 00511 (LINC00511) has been found to be upregulated and acts as an oncogene in breast cancer, but little is known about its expression pattern, biological function and underlying mechanism in NSCLC. Herein, we identified LINC00511 as an oncogenic lncRNA by driving tumorigenesis in NSCLC. We found LINC00511 was upregulated and associated with oncogenesis, tumor size, metastasis, and poor prognosis in NSCLC. Moreover, LINC00511 affected cell proliferation, invasiveness, metastasis, and apoptosis in multiple NSCLC cell lines. Mechanistically, LINC00511 bound histone methyltransferase enhancer of zeste homolog 2 ((EZH2, the catalytic subunit of the polycomb repressive complex 2 (PRC2), a highly conserved protein complex that regulates gene expression by methylating lysine 27 on histone H3), and acted as a modular scaffold of EZH2/PRC2 complexes, coordinated their localization, and specified the histone modification pattern on the target genes, including p57, and consequently altered NSCLC cell biology. Thus, LINC00511 is mechanistically, functionally, and clinically oncogenic in NSCLC. Targeting LINC00511 and its pathway may be meaningful for treating patients with NSCLC.

Inflammation is widely distributed in patients with Duchenne muscular dystrophy (DMD), and ultimately leads to progressive deterioration of muscle function with chronic muscle damage, oxidative stress and reduced oxidative capacity. NF-E2-related factor 2 (Nrf2) plays a critical role in defending against inflammation in different tissues via activation of phase II enzymes, heme oxygenase-1 (HO-1), and inhibition of NF-κB signaling pathway. However, the role of Nrf2 in the inflammation of dystrophic muscle remains unknown. To determine whether Nrf2 may counteract inflammation in dystrophic muscle, we treated 4-week-old male mdx mice with Nrf2 activator sulforaphane (SFN) by gavage (2 mg/kg body weight per day) for 4 weeks. The experimental results demonstrated that SFN treatment increased the expression of muscle phase II enzymes HO-1 with Nrf2 dependent manner. Inflammation in mice was reduced by SFN treatment as indicated by decreased infiltration of immune cell and expression of the inflammatory cytokines CD45, pro-inflammatory cytokines tumor necrosis factor-α, interleukin-1β and interleukin-6 in the skeletal muscles of mdx mice. In addition, SFN treatment also decreased the expression of NF-κB (p65) and phosphorylate-IκB kinase(IKK)-α，as well as increased inhibitor of κB (IκB)-α expression in mdx mice with Nrf2 dependent manner. Collectively, these results show that SFN-induced Nrf2 can alleviate muscle inflammation in mdx mice by inhibiting NF-κB signaling pathway.

Background: Long non-coding RNAs (lncRNAs) are extensively intricate in the tumorigenesis and metastasis of various cancer types. Nevertheless, the detailed molecular mechanisms of lncRNA in non-small cell lung cancer (NSCLC) still remain mainly undetermined. Methods: qPCR was performed to verify LINC00301 expression in NSCLC clinical specimens or cell lines. Fluorescence in situ hybridization (FISH) was conducted to identify the localization of LINC00301 in NSCLC cells. Chromatin immunoprecipitation (ChIP) was subjected to validate the binding activity between FOXC1 and LINC00301 promoters. RNA immunoprecipitation (RIP) was performed to explore the binding activity between LINC00301 and EZH2. RNA pull-down followed by dot-blot, protein domain mapping, and RNA electrophoresis mobility shift assay (EMSA) were conducted to identify the detailed binding regions between LINC00301 and EZH2. Alpha assay was conducted to quantitatively assess the interaction between LINC00301 and EZH2. Results: LINC00301 is highly expressed in NSCLC and closely corelated to its prognosis by analyzing the relationship between differentially expressed lncRNAs and prognosis in NSCLC samples. in vitro and in vivo experiments revealed that LINC00301 facilitates cell proliferation, releases NSCLC cell cycle arrest, promotes cell migration and invasion, and suppresses cell apoptosis in NSCLC. In addition, LINC00301 increases regulatory T cell (Treg) while decreases CD8⁺ T cell population in LA-4/SLN-205-derived tumors through targeting TGF-β. The transcription factor FOXC1 mediates LINC00301 expression in NSCLC. Bioinformatics prediction and in vitro experiments indicated that LINC00301 (83–123 nucleotide [nt]) can directly bind to the enhancer of zeste homolog 2 (EZH2) (612–727 amino acid [aa]) to promote H3K27me3 at the ELL protein-associated factor 2 (EAF2) promoter. EAF2 directly binds and stabilizes von Hippel–Lindau protein (pVHL), so downregulated EAF2 augments hypoxia-inducible factor 1 α (HIF1α) expression by regulating pVHL in NSCLC cells. Moreover, we also found that LINC00301 could function as a competing endogenous RNA (ceRNA) against miR-1276 to expedite HIF1α expression in the cytoplasm of NSCLC cells. Conclusions: In summary, our present research revealed the oncogenic roles of LINC00301 in clinical specimens as well as cellular and animal experiments, illustrating the potential roles and mechanisms of the FOXC1/LINC00301/EZH2/EAF2/pVHL/HIF1α and FOXC1/LINC00301/miR-1276/HIF1α pathways, which provides novel insights and potential theraputic targets to NSCLC.