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Long non-coding RNAs (lncRNAs) have been to regulate tumor progression and therapy resistance through various molecular mechanisms. In this study, we investigated the role of lncRNAs in nasopharyngeal carcinoma (NPC) and the underlying mechanism. Using lncRNA arrays to analyze the lncRNA profiles of the NPC and para-tumor tissues, we detected the novel lnc-MRPL39-2:1, which was validated by in situ hybridization and by the 5' and 3' rapid amplification of the cDNA ends. Further, its role in NPC cell growth and metastasis was verified in vitro and in vivo . The researchers conducted the RNA pull-down assays, mass spectrometry (MS), dual-luciferase reporter assays, RNA immunoprecipitation (RIP) assays, and the MS2-RIP assays were then used to identify the lnc-MRPL39-2:1-interacting proteins and miRNAs. We found that lnc-MRPL39-2:1, which was highly expressed in in NPC tissues, was related to a poor prognosis in NPC patients. Furthermore, lnc-MRPL39-2:1 was shown to induce the growth and invasion of NPC by interacting directly with the Hu-antigen R (HuR) to upregulate β-catenin expression both in vivo and in vitro . Lnc-MRPL39-2:1 expression was also suppressed by microRNA (miR)-329. Thus, these findings indicate that lnc-MRPL39-2:1 is essential in NPC tumorigenesis and metastasis and highlight its potential as a prognostic marker and therapeutic target for NPC., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: Distant metastasis and recurrence remain the main obstacle to nasopharyngeal carcinoma (NPC) treatment. However, the molecular mechanisms underlying NPC growth and metastasis are poorly understood., Methods: LHX2 expression was examined in NPC cell lines and NPC tissues using quantitative reverse transcription-polymerase chain reaction, western blotting and Immunohistochemistry assay. NPC cells overexpressing or silencing LHX2 were used to perform CCK-8 assay, colony-formation assay, EdU assay, wound-healing and invasion assays in vitro. Xenograft tumour models and lung metastasis models were involved for the in vivo assays. The Gene Set Enrichment Analysis (GSEA), ELISA assay, western blot, chromatin immunoprecipitation (ChIP) assay and Luciferase reporter assay were applied for the downstream target mechanism investigation., Results: LIM-homeodomain transcription factor 2 (LHX2) was upregulated in NPC tissues and cell lines. Elevated LHX2 was closely associated with poor survival in NPC patients. Ectopic LHX2 overexpression dramatically promoted the growth, migration and invasion of NPC cells both in vitro and in vivo. Mechanistically, LHX2 transcriptionally increased the fibroblast growth factor 1 (FGF1) expression, which in turn activated the phosphorylation of STAT3 (signal transducer and activator of transcription 3), ERK1/2 (extracellular regulated protein kinases 1/2) and AKT signalling pathways in an autocrine and paracrine manner, thereby promoting the growth and metastasis of NPC. Inhibition of FGF1 with siRNA or FGFR inhibitor blocked LHX2-induced nasopharyngeal carcinoma cell growth, migration and invasion., Conclusions: Our study identifies the LHX2-FGF1-FGFR axis plays a key role in NPC progression and provides a potential target for NPC therapy., (© 2022. The Author(s).)

Cancer stem cells (CSCs) are a source of tumour recurrence in patients with nasopharyngeal carcinoma (NPC); however, the function of microRNA-124 (miR-124) in NPC CSCs has not been clearly defined. In this study, we investigated the role of miR-124 in NPC CSCs. qRT-PCR was performed to measure miR-124 expression in NPC tissues and cell lines and the effects of miR-124 on stem-like properties and radiosensitivity of NPC cells measured. Luciferase reporter assays and rescue experiments were used to investigate the interaction of miR-124 with the 3'UTR of junctional adhesion molecule A (JAMA). Finally, we examined the effects of miR-124 in an animal model and clinical samples. Down-regulation of miR-124 was detected in cancer tissues and was inversely associated with tumour stage and lymph node metastasis. Overexpression of miR-124 inhibited stemness properties and enhanced radiosensitivity of NPC cells in vitro and in vivo via targeting JAMA. Up-regulation of miR-124 was correlated with superior overall survival of patients with NPC. Our study demonstrates that miR-124 can inhibit stem-like properties and enhance radiosensitivity by directly targeting JAMA in NPC. These findings provide novel insights into the molecular mechanisms underlying therapy failure in NPC., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Radiotherapy is essential to treat breast cancer and microRNA (miRNA) miR-200c is considered as a radiosensitizer of breast cancer. However, the molecular mechanisms by which miR-200c regulates radiosensitivity remain largely unknown. In the present study, we showed that induction of miR-200c led to widespread alteration in long noncoding RNA (lncRNA) expression in breast cancer cells. We identified lncRNA LINC02582 as a target of miR-200c. Inhibition of LINC02582 expression increased radiosensitvity, while overexpression of LINC02582 promoted radioresistance. Mechanistically, LINC02582 interacts with deubiquitinating enzyme ubiquitin specific peptidase 7 (USP7) to deubiquitinate and stabilize checkpoint kinase 1 (CHK1), a critical effector kinase in DNA damage response, thus promoting radioresistance. Furthermore, we detected an inverse correlation between the expression of miR-200c vs. LINC02582 and CHK1 in breast cancer samples. These findings identified LINC02582 as a downstream target of miR-200c linking miR-200c to CHK1, in which miR-200c increases radiosensitivity by downregulation of CHK1.

Recurrence or metastasis resulting from radioresistance are the main challenges for the treatment of nasopharyngeal carcinoma (NPC). A great deal of evidence supports the role of abnormal expression of miRNAs in radioresistance and malignancy. In some cancers, miR-483-5p is associated with inferior disease-specific survival. Therefore, we investigated the role of miR-483-5p in NPC radiosensitivity and the mechanism by which the miR-483-5p affects the radiosensitivity of NPC cells. In this study, we show that the overexpression of miR-483-5p decreases the radiosensitivity of NPC cells in vitro and in vivo. Mechanistically, miR-483-5p exerts these functions by decreasing radiation-induced apoptosis and DNA damage, and by increasing NPC cell colony formation, via targeting death-associated protein kinase 1 (DAPK1). Finally, our results confirm that the upregulation of miR-483-5p is correlated with advanced clinical stage and inferior overall survival of patients with NPC. These findings provide novel insights into our understanding of the molecular mechanisms underlying therapy failure in NPC. Modulation of miR-483-5p and DAPK1 levels may provide a new approach for increasing the radiosensitivity of these tumors.

MicroRNAs (miRNAs) have been documented as having an important role in the development of cancer. Broccoli is very popular in large groups of the population and has anticancer properties. Junctional adhesion molecule A (JAMA) is preferentially concentrated at tight junctions and influences cell morphology and migration. Epithelial-mesenchymal transition (EMT) is a developmental program associated with cancer progression and metastasis. In this study we aimed to investigate the role of miRNAs from broccoli in human nasopharyngeal cancer (NPC). We demonstrated that a total of 84 conserved miRNAs and 184 putative novel miRNAs were found in broccoli by sequencing technology. Among these, miR156a was expressed the most. In addition, synthetic miR156a mimic inhibited the EMT of NPC cells in vitro. Furthermore, it was confirmed that JAMA was the target of miR156a mimic as validated by 3' UTR luciferase reporter assays and western blotting. Knockdown of JAMA was consistent with the effects of miR156a mimic on the EMT of NPC, and the up-regulation of JAMA could partially restore EMT repressed by miR156a mimic. In conclusion, these results indicate that the miR156a mimic inhibits the EMT of NPC cells by targeting the 3' UTR of JAMA. These miRNA profiles of broccoli provide a fundamental basis for further research. Moreover, the discovery of miR156a may have clinical implications for the treatment of patients with NPC.

Background: MicroRNAs (miRNAs) are a new class of endogenous regulators of a broad range of physiological processes, which act by regulating gene expression post-transcriptionally. The brassica vegetable, broccoli (Brassica oleracea var. italica), is very popular with a wide range of consumers, but environmental stresses such as salinity are a problem worldwide in restricting its growth and yield. Little is known about the role of miRNAs in the response of broccoli to salt stress. In this study, broccoli subjected to salt stress and broccoli grown under control conditions were analyzed by high-throughput sequencing. Differential miRNA expression was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR). The prediction of miRNA targets was undertaken using the Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology (KO) database and Gene Ontology (GO)-enrichment analyses., Results: Two libraries of small (or short) RNAs (sRNAs) were constructed and sequenced by high-throughput Solexa sequencing. A total of 24,511,963 and 21,034,728 clean reads, representing 9,861,236 (40.23%) and 8,574,665 (40.76%) unique reads, were obtained for control and salt-stressed broccoli, respectively. Furthermore, 42 putative known and 39 putative candidate miRNAs that were differentially expressed between control and salt-stressed broccoli were revealed by their read counts and confirmed by the use of stem-loop real-time RT-PCR. Amongst these, the putative conserved miRNAs, miR393 and miR855, and two putative candidate miRNAs, miR3 and miR34, were the most strongly down-regulated when broccoli was salt-stressed, whereas the putative conserved miRNA, miR396a, and the putative candidate miRNA, miR37, were the most up-regulated. Finally, analysis of the predicted gene targets of miRNAs using the GO and KO databases indicated that a range of metabolic and other cellular functions known to be associated with salt stress were up-regulated in broccoli treated with salt., Conclusion: A comprehensive study of broccoli miRNA in relation to salt stress has been performed. We report significant data on the miRNA profile of broccoli that will underpin further studies on stress responses in broccoli and related species. The differential regulation of miRNAs between control and salt-stressed broccoli indicates that miRNAs play an integral role in the regulation of responses to salt stress.