Involvement of NEAT1/miR-133a axis in promoting cervical cancer progression via targeting SOX4

NEAT1 is an important tumor oncogenic gene in various tumors. Nevertheless, its involvement remains poorly studied in cervical cancer. Our study explored the functional mechanism of NEAT1 in cervical cancer. NEAT1 level in several cervical cancer cells was quantified and we found NEAT1 was greatly upregulated in vitro. NEAT1 knockdown inhibited cervical cancer development through repressing cell proliferation, colony formation, capacity of migration, and invasion and also inducing the apoptosis. For another, microRNA (miR)-133a was downregulated in cervical cancer cells and NEAT1 negatively modulated miR-133a expression. Subsequently, we validated that miR-133a functioned as a potential target of NEAT1. Meanwhile, SOX4 is abnormally expressed in various cancers. SOX4 was able to act as a downstream target of miR-133a and silencing of SOX4 can restrain cervical cancer progression. In addition, in vivo assays were conducted to prove the role of NEAT1/miR-133a/SOX4 axis in cervical cancer. These findings implied that NEAT1 served as a competing endogenous RNA to sponge miR-133a and regulate SOX4 in cervical cancer pathogenesis. To sum up, it was implied that NEAT1/miR-133a/SOX4 axis was involved in cervical cancer development.     

Long noncoding RNA NEAT1-modulated miR-506 regulates gastric cancer development through targeting STAT3

Accumulating evidence has indicated that long noncoding RNA NEAT1 exerts critical roles in cancers. So far, the detailed biological role and mechanisms of NEAT1, which are responsible for human gastric cancer (GC), are still largely unknown. Here, we observed that NEAT1 and STAT3 expressions were significantly upregulated in human GC cells including BGC823, SGC-7901, AGS, MGC803, and MKN28 cells compared with normal gastric epithelial cells GES-1, while miR-506 was downregulated. We inhibited NEAT1 and observed that NEAT1 inhibition was able to repress the growth, migration, and invasion of GC cells. Conversely, overexpression of NEAT1 exhibited an increased ability of GC progression in BGC823 and SGC-7901 cells. Bioinformatics analysis, dual luciferase reporter assays, RIP assays, and RNA pull-down tests validated the negative binding correlation between NEAT1 and miR-506. In addition, it was found that miR-506 can modulate the expression of NEAT1 in vitro. STAT3 was predicted as a messenger RNA (mRNA) target of miR-506, and miR-506 mimics can suppress STAT3 mRNA expression. Subsequently, it was observed that downregulation of NEAT1 can restrain GC development by decreasing STAT3, which can be reversed by miR-506 inhibitors. Therefore, it was hypothesized in our study that NEAT1 can be recognized as a competing endogenous RNA to modulate STAT3 by sponging miR-506 in GC. In conclusion, we implied that NEAT1 can serve as an important biomarker in GC diagnosis and treatment.     

Unusual semi‐extractability as a hallmark of nuclear body‐associated architectural noncoding RNAs

NEAT1_2 long noncoding RNA (lncRNA) is the molecular scaffold of paraspeckle nuclear bodies. Here, we report an improved RNA extraction method: extensive needle shearing or heating of cell lysate in RNA extraction reagent improved NEAT1_2 extraction by 20‐fold (a property we term “semi‐extractability”), whereas using a conventional method NEAT1_2 was trapped in the protein phase. The improved extraction method enabled us to estimate that approximately 50 NEAT1_2 molecules are present in a single paraspeckle. Another architectural lncRNA, IGS16, also exhibited similar semi‐extractability. A comparison of RNA‐seq data from needle‐sheared and control samples revealed the existence of multiple semi‐extractable RNAs, many of which were localized in subnuclear granule‐like structures. The semi‐extractability of NEAT1_2 correlated with its association with paraspeckle proteins and required the prion‐like domain of the RNA‐binding protein FUS. This observation suggests that tenacious RNA–protein and protein–protein interactions, which drive nuclear body formation, are responsible for semi‐extractability. Our findings provide a foundation for the discovery of the architectural RNAs that constitute nuclear bodies.     

MicroRNA 140 Promotes Expression of Long Noncoding RNA NEAT1 in Adipogenesis

More than 40% of the U.S. population are clinically obese and suffer from metabolic syndrome with an increased risk of postmenopausal estrogen receptor-positive breast cancer. Adipocytes are the primary component of adipose tissue and are formed through adipogenesis from precursor mesenchymal stem cells. While the major molecular pathways of adipogenesis are understood, little is known about the noncoding RNA signaling networks involved in adipogenesis. Using adipocyte-derived stem cells (ADSCs) isolated from wild-type and microRNA 140 (miR-140) knockout mice, we identify a novel miR-140/long noncoding RNA (lncRNA) NEAT1 signaling network necessary for adipogenesis. miR-140 knockout ADSCs have dramatically decreased adipogenic capabilities associated with downregulation of NEAT1 expression. We identified a miR-140 binding site in NEAT1 and found that mature miR-140 in the nucleus can physically interact with NEAT1, leading to increased NEAT1 expression. We demonstrated that reexpression of NEAT1 in miR-140 knockout ADSCs is sufficient to restore their ability to undergo differentiation. Our results reveal an exciting new noncoding RNA signaling network that regulates adipogenesis and that is a potential new target in the prevention or treatment of obesity.     

Long noncoding RNA HOXD-AS1 induces epithelial-mesenchymal transition in breast cancer by acting as a competing endogenous RNA of miR-421

Breast cancer (BCa) is the most common malignant tumor in females. Long noncoding RNAs (lncRNAs) are deregulated in many types of human cancers, including BCa. The purpose of the present study was to examine the expression profile and biological role of HOXD cluster antisense RNA 1 (HOXD-AS1) in BCa. Our results revealed that HOXD-AS1 was upregulated in BCa tissues and cell lines, and high HOXD-AS1 expression was correlated with aggressive clinicopathological characteristics of BCa patients. Further gain-of-function and loss-of-function analysis showed that HOXD-AS1 overexpression promoted, whereas HOXD-AS1 knockdown inhibited BCa cell proliferation, cell cycle progression, migration, and invasion, indicating that HOXD-AS1 may function as a novel oncogene in BCa. Mechanistically, HOXD-AS1 could activate epithelial-mesenchymal transition (EMT) in BCa cells. We further proved that HOXD-AS1 might serve as a competing endogenous RNA of miR-421 in BCa cells, and miR-421 was downregulated and negatively correlated with HOXD-AS1 expression in BCa tissues. Besides, we confirmed that SOX4, a master regulator of EMT, was a direct target gene of miR-421. Further, rescue experiments suggested that miR-421 overexpression partly abrogated the oncogenic role of HOXD-AS1 in BCa cells. Therefore, we shed light on that HOXD-AS1/miR-421/SOX4 axis may be considered as a novel therapeutic target for the treatment of BCa patients.     

Long non-coding RNA PVT1-5 promotes cell proliferation by regulating miR-126/SLC7A5 axis in lung cancer

Dysregulated long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) play key roles in the development of human cancers. The lncRNA plasmacytoma variant translocation 1 (PVT1) is reported to be an oncogene in a variety of cancers. However, the roles of PVT1-5 and its related miRNAs in lung cancer are poorly understood. In this study, we found that PVT1-5 expression was significantly increased in lung cancer tissues and cell lines. By using biotin-labeled lncRNA-PVT1-5 probe for miRNA in vivo precipitation (miRIP) in lung cancer cells and dual-luciferase reporterassays, we identified that miR-126 was associated with lncRNA-PVT1-5. Furthermore, knockdown of lncRNA-PVT1-5 in cells could down-regulate the expression of SLC7A5, the target of oncogenic miR-126, resulting in the cell proliferation. Conversely, inhibiting the expression of miR-126 markedly increased the expression of SLC7A5 and alleviated cell proliferation inhibition. Thus, our results indicated that lncRNA-PVT1-5 may function as a competing endogenous RNA (ceRNA) for miR-126 to promote cell proliferation by regulating the miR-126/SLC7A5 pathway, suggesting that lncRNA-PVT1-5 plays a crucial role in lung cancer progression and lncRNA-PVT1-5/miR-126/SLC7A5 regulatory network may shed light on tumorigenesis in lung cancer.