Knockdown of Lncrna PVT1 Enhances Radiosensitivity in Non-Small Cell Lung Cancer by Sponging Mir-195

Background/Aims: Whether the level of long noncoding RNA plasmacytoma variant translocation 1 gene (lncRNA PVT1) expression influences the clinical development and outcome of human cancers has not been thoroughly elucidated to date. Inconsistencies still exist regarding the associations between PVT1 and the clinicopathological features, including patient survival data. Additionally, the regulatory mechanism of PVT1 among human cancers remains unclear. Methods: we conducted a comprehensive inquiry to verify the implication of PVT1 expression in cancer patients by conducting a meta-analysis of 19 selected studies and The Cancer Genome Atlas (TCGA) database to examine the relationship between PVT1 expression and both the prognosis and clinicopathological features of cancer patients using STATA 12.0. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses of the potential mRNA target genes of PVT1 gathered from TANRIC and Multi Experiment Matrix (MEM) were performed. Results: The level of PVT1 expression in tumor tissues was higher than in paired non-cancer tissues and was significantly associated with a poorer prognosis in cancer patients. Additionally, overexpression of PVT1 was significantly correlated with histological differentiation, tumor (T) classification, lymph node (N) classification and TNM stages. Furthermore, a total of 462 validated target genes were identified, and the GO and KEGG analyses demonstrated that the validated targets of PVT1 were significantly enriched in several pathways, including the GnRH signaling pathway, the Cytokine-cytokine receptor interaction pathway, the Inflammatory mediator regulation of TRP channels pathway, and the Neuroactive ligand-receptor interaction pathway. Conclusion: PVT1 may serve as a potential biomarker associated with the progression and prognosis of human cancers.

Section: Discussionmentioning

confidence: 82%

Prognostic Significance of LncRNA PVT1 and Its Potential Target Gene Network in Human Cancers: a Comprehensive Inquiry Based Upon 21 Cancer Types and 9972 Cases

Qin

Lin

et al. 2018

“…Quantitative real-time polymerase chain reaction assay As described previously [4,38], TRIzol reagent was used to extract total cellular RNA, which was then reverse-transcribed. cDNA was then amplified by quantitative real-time polymerase chain reaction (qPCR).…”

Section: Cell Culturementioning

confidence: 99%

Long Non-Coding RNA MALAT1 Protects Human Osteoblasts from Dexamethasone-Induced Injury via Activation of PPM1E-AMPK Signaling

Fan¹,

Zhang²,

Liu³

et al. 2018

Background/Aims: Dexamethasone (Dex) induces injuries to human osteoblasts. In this study, we tested the potential role of the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (Lnc-MALAT1) in this process. Materials: Two established human osteoblastic cell lines (OB-6 and hFOB1.19) and primary human osteoblasts were treated with Dex. Lnc-MALAT1 expression was analyzed by quantitative real-time polymerase chain reaction assay. Cell viability, apoptosis, and death were tested by the MTT assay, histone-DNA assay, and trypan blue staining assay, respectively. AMP-activated protein kinase (AMPK) signaling was evaluated by western blotting and AMPK activity assay. Results: Lnc-MALAT1 expression was downregulated by Dex treatment in the established osteoblastic cell lines (OB-6 and hFOB1.19) and primary human osteoblasts. The level of Lnc-MALAT1 was decreased in the necrotic femoral head tissues of Dex-administered patients. In osteoblastic cells and primary human osteoblasts, forced overexpression of Lnc-MALAT1 using a lentiviral vector (LV-MALAT1) inhibited Dex-induced cell viability reduction, cell death, and apoptosis. Conversely, transfection with Lnc-MALAT1 small interfering RNA aggravated Dex-induced cytotoxicity. Transfection with LV-MALAT1 downregulated Ppm1e (protein phosphatase, Mg^2+/ Mn²⁺-dependent 1e) expression to activate AMPK signaling. Treatment of osteoblasts with AMPKα1 short hairpin RNA or dominant negative mutation (T172A) abolished LV-MALAT1-induced protection against Dex-induced cytotoxicity. Furthermore, LV-MALAT1 induced an increase in nicotinamide adenine dinucleotide phosphate activity and activation of Nrf2 signaling. Dex-induced reactive oxygen species production was significantly attenuated by LV-MALAT1 transfection in osteoblastic cells and primary osteoblasts. Conclusion: Lnc-MALAT1 protects human osteoblasts from Dex-induced injuries, possibly via activation of Ppm1e-AMPK signaling.

“…Recently, several studies have suggested that miRNAs play a role in the radiation resistance of NSCLC by interacting with tumor-related genes [24, 25]. Hence, it is important to characterize tumor-related miRNAs and their tumor-relevant gene targets [26]. Furthermore, by exploring the biological significance of these genes, we can identify novel therapeutic targets for enhancing the efficacy of radiation therapy and improve the survival of these patients.…”

Section: Discussionmentioning

confidence: 99%

MiR-99a Enhances the Radiation Sensitivity of Non-Small Cell Lung Cancer by Targeting mTOR

Yin

Chen

et al. 2018

Background/Aims: Radiation therapy is an important and effective modality for the treatment of non-small cell lung cancer (NSCLC). MicroRNAs (miRNAs) are crucial post-transcriptional regulators that are involved in numerous important biologic processes. However, their potential involvement in radiation sensitivity remains unknown. Materials: We performed integrated analysis of miRNA expression in NSCLC using The Cancer Genome Atlas datasets. miR-99a was found to be significantly upregulated in cancer tissue and regulated cell survival. Cell culture was used to assess the role of miR-99a in radiation sensitivity. We then used flow cytometry to examine the effects of miR-99a on the cell cycle and apoptosis in cells exposed to radiation. To identify gene targets of miR-99a, a bioinformatics approach was adopted, and the findings of this analysis were verified using luciferase reporter assays. Finally, an in vivo study was conducted to examine the effect of miR-99a on tumor volume in an NSCLC mouse model undergoing radiation therapy. Results: miR-99a was significantly upregulated in radiation-sensitive A549 cells compared with radiation-resistant A549 cells. miR-99a overexpression was shown to enhance radiosensitivity, while inhibition of miR-99a resulted in radioresistance of NSCLC cell lines in vitro and in vivo. In addition, by bioinformatics software analysis and luciferase assays, mammalian target of rapamycin (mTOR) was identified as a direct target of miR-99a. Furthermore, AZD2014, an inhibitor of mTOR, enhanced radiosensitivity and apoptosis in NSCLC cell lines, while mTOR overexpression resulted in radioresistance and cell survival from miR-99a-induced cell apoptosis. Moreover, miR-99a overexpression further increased the efficacy of radiation therapy in an NSCLC xenograft mouse model, and miR-99a and mTOR expression was significantly inversely correlated. Conclusions: Altogether, these data suggested miR-99a functions as a tumor suppressor that has a critical role in regulating radiosensitivity of NSCLC by targeting the mTOR signaling pathway.