LncRNA MNX1-AS1 Contributes to Laryngeal Squamous Cell Carcinoma Growth and Migration by Regulating mir-744-5p/bcl9/β-Catenin Axis

The role of miRNAs in laryngeal cancer pathogenesis and therapeutic resistance - A focus on signaling pathways interplay

Laryngeal cancer (LC)is the malignancy of the larynx (voice box). The majority of LC are squamous cell carcinomas. Many risk factors were reported to be associated with LC as tobacco use, obesity, alcohol intake, human papillomavirus (HPV) infection, and asbestos exposure. Besides, epigenetics as non-coding nucleic acids also have a great role in LC. miRNAs are short nucleic acid molecules that can modulate multiple cellular processes by regulating the expression of their genes. Therefore, LC progression, apoptosis evasions, initiation, EMT, and angiogenesis are associated with dysregulated miRNA expressions. miRNAs also could have some vital signaling pathways such as mTOR/P-gp, Wnt/-catenin signaling, JAK/STAT, KRAS, and EGF. Besides, miRNAs also have a role in the modulation of LC response to different therapeutic modalities. In this review, we have provided a comprehensive and updated overview highlighting the microRNAs biogenesis, general biological functions, regulatory mechanisms, and signaling dysfunction in LC carcinogenesis, in addition to their clinical potential for LC diagnosis, prognosis, and chemotherapeutics response implications.

Diagnostic and Prognostic Value of microRNAs in Patients with Laryngeal Cancer: A Systematic Review

Laryngeal squamous cell cancer (LSCC) is one of the most common malignant tumors of the head and neck region, with a poor survival rate (5-year overall survival 50-80%) as a consequence of an advanced-stage diagnosis and high recurrence rate. Tobacco smoking and alcohol abuse are the main risk factors of LSCC development. An early diagnosis of LSCC, a prompt detection of recurrence and a more precise monitoring of the efficacy of different treatment modalities are currently needed to reduce the mortality. Therefore, the identification of effective diagnostic and prognostic biomarkers for LSCC is crucial to guide disease management and improve clinical outcomes. In the past years, a dysregulated expression of small non-coding RNAs, including microRNAs (miRNAs), has been reported in many human cancers, including LSCC, and many miRNAs have been explored for their diagnostic and prognostic potential and proposed as biomarkers. We searched electronic databases for original papers that were focused on miRNAs and LSCC, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. According to the outcome, 566 articles were initially screened, of which 177 studies were selected and included in the analysis. In this systematic review, we provide an overview of the current literature on the function and the potential diagnostic and prognostic role of tissue and circulating miRNAs in LSCC.

LncRNA CARMN inhibits cervical cancer cell growth via the miR-92a-3p/BTG2/Wnt/β-catenin axis

Long noncoding RNA (lncRNA) cardiac mesoderm enhancer-associated noncoding RNA (CARMN) is a newly discovered tumor-suppressor lncRNA in cancers. However, its role in cervical cancer (CC) remains elusive. This study was conducted to analyze the molecular mechanism of CARMN in CC cell growth and provide a novel theoretical basis for CC treatment. RT-qPCR and clinical analysis revealed that CARMN and B-cell translocation gene 2 (BTG2) were downregulated, whereas miR-92a-3p was upregulated in CC tissues and cells and their expressions were correlated with clinicopathological characteristics and prognosis. MTT assay, flow cytometry, and Transwell assays revealed that CARMN overexpression reduced proliferation, migration, and invasion and increased apoptosis rate in CC cells. Mechanically, CARMN repressed miR-92a-3p to promote BTG2 transcription. Functional rescue assays revealed that miR-92a-3p overexpression or BTG2 downregulation reversed the inhibitory role of CARMN overexpression in CC cell growth. Western blot analysis elicited that Wnt3a and β-catenin were elevated in CC cells and CARMN blocked the Wnt/β-catenin signaling pathway via the miR-92a-3p/BTG2 axis. Overall, our findings demonstrated that CARMN repressed miR-92a-3p to upregulate BTG2 transcription and then blocked the Wnt/β-catenin signaling pathway, thereby suppressing CC cell growth.

Activation of MYO1G by lncRNA MNX1-AS1 Drives the Progression in Lung Cancer

Lung cancer represents the most prevalent cancer worldwide and causes the death of many patients. Cancer stem cells (CSCs), a subpopulation of cancer cells, have the capacities of self-renewal, unlimited proliferation, and multiple differentiation potential. The purpose of this study was to explore the potential role of long noncoding RNA (lncRNA) MNX1-AS1 on maintaining the stemness of CSC in lung cancer. CSCs were firstly sorted by flow cytometry. After the determination of the target of the present study using Gene Expression Omnibus dataset, MNX1-AS1was found to be highly expressed in lung cancer tissues and cells. Deletion of MNX1-AS1 inhibited proliferation, migration, invasion and sphere-forming abilities of CSC. Furthermore, subcellular fractionation, fluorescence in situ hybridization, RNA immunoprecipitation, and dual-luciferase experiments demonstrated that MNX1-AS1 recruited the transcription factor POU domain class 2 transcription factor 2 (POU2F2) to the nucleus and activated the myosin IG (MYO1G) expression. MYO1G overexpression partially reversed the si-MNX1-AS1-decreased stemness of CSCs. Finally, MNX1-AS1 suppression significantly repressed the growth of xenografts in vivo. Our study highlights the importance of the MNX1-AS1/POU2F2/MYO1G axis in stem cell-like properties of lung cancer cells.

Potentials of lncRNA-miRNA-mRNA networks as biomarkers for laryngeal squamous cell carcinoma

Chemoresistance, radioresistance, and facile spreading of laryngeal squamous cell carcinoma (LSCC) make the practically clinical treatment invalid. Such dismal outcome mainly originates from the lack of effective biomarkers which are highly desirable to understand the pathogenesis of LSCC, and strives to find promising novel biomarkers to improve early screening, effective treatment, and prognosis evaluation in LSCC. Recently, long non-coding RNAs (lncRNAs), a kind of non-coding RNAs longer than 200 nucleotides, can participate in the process of tumorigenesis and progression through many regulatory modalities, such as epigenetic transcriptional regulation and post-transcriptional regulation. Meanwhile, microRNAs (miRNAs, miRs), essentially involved in the post-transcriptional regulation of gene expression, are aberrantly expressed in cancer-related genomic regions or susceptible sites. An increasing number of studies have shown that lncRNAs are important regulators of miRNAs expression in LSCC, and that miRNAs can also target to regulate the expression of lncRNAs, and they can target to regulate downstream messenger RNAs (mRNAs) transcriptionally or post-transcriptionally, thereby affecting various physiopathological processes of LSCC. Complex cross-regulatory networks existing among lncRNAs, miRNAs, and mRNAs can regulate the tumorigenesis and development of LSCC. Such networks may become promising biomarkers and potential therapeutic targets in the research field of LSCC. In this review, we mainly summarize the latest research progress on the regulatory relationships among lncRNAs, miRNAs, and downstream mRNAs, and highlight the potential applications of lncRNA-miRNA-mRNA regulatory networks as biomarkers for the early diagnosis, epithelial-mesenchymal transition (EMT) process, chemoresistance, radioresistance, and prognosis of LSCC, aiming to provide important clues for understanding the pathogenesis of LSCC and developing new diagnostic and therapeutic strategies.

MNX1-AS1, a c-Myc induced lncRNA, promotes the Warburg effect by regulating PKM2 nuclear translocation

BACKGROUND

Altered glycolysis is the most fundamental metabolic change associated with the Warburg effect. Some glycolytic enzymes such as PKM2, the dominant pyruvate kinase in cancer cells, have been shown to engage in non-glycolytic functions that contribute to tumor metabolism. However, the precise mechanisms are not completely understood.

METHODS

The role of MNX1-AS1 in hepatocellular carcinoma progression was assessed both in vitro and in vivo. Northern blotting, RNA pulldown, mass spectrometry, RNA-binding protein immunoprecipitation, ChIP, luciferase reporter assays, RNA FISH and immunofluorescence staining were used to explore the detail molecular mechanism of MNX1-AS1 in hepatocellular carcinoma (HCC).

RESULTS

Here we dissect how MNX1-AS1, a long non-coding RNA (lncRNA), reinforces the Warburg effect through facilitating the non-glycolytic actions of PKM2 in the cell nucleus. We found that MNX1-AS1 expression was frequently overexpressed in HCC-derived cell lines and tissues compared to their normal hepatic cell counterparts, a finding consistent with its status as pan-cancer expressed lncRNA. In the context of HCC, we show MNX1-AS1 acts as a scaffold to promote interactions between PKM2 and importin α5. In response to EGFR activation, the resulting ternary complex drives the translocation of PKM2 into the nucleus. In consequence, glycolytic pathway components including key mediators of the Warburg effect (LDHA, GLUT1 and PDK1) are upregulated though the coactivator function of PKM2. Manipulating MNX1-AS1 elicited robust effects on glycolysis associated with marked changes in HCC growth in vitro and in xenograft models, indicative of the significant contribution of MNX1-AS1 to tumorigenic phenotypes. Moreover, while MNX1-AS1 expression is driven by c-Myc, its actions associated with PKM2 were shown to be downstream and independent of c-Myc.

CONCLUSIONS

Given the status of MNX1-AS1 as a pan-cancer upregulated lncRNA, this implicitly highlights the potential of targeting MNX1-AS1 to selectively counter the Warburg effect in a range of tumor types.

LncRNA MNX1-AS1: A novel oncogenic propellant in cancers

To date, recent studies have shown that long non-coding RNAs (lncRNAs) are key players in gene regulation processes involved in cancer pathogenesis. In general, Motor neuron and pancreas homeobox 1-antisense RNA1 (MNX1-AS1) is highly expressed in all cancers as reported so far and exerts oncogenic effects through different mechanisms. In this review, we comprehensively summarize the detailed mechanisms of potential functions of MNX1-AS1 in different cancer types as well as the latest knowledge highlighting the potential of MNX1-AS1 as a therapeutic target for cancer. Aberrant expression of MNX1-AS1 closely correlates with clinicopathological parameters. such as lymphatic metastasis, tumor size, tumor stage, OS and DFS. Thus, MNX1-AS1 can be used as a diagnostic and prognostic biomarker or even a therapeutic prognostic target. This article reviews its function, molecular mechanism and clinical prognosis in various malignancies.

Actinidia chinensis Planch Root extract suppresses the growth and metastasis of hypopharyngeal carcinoma by inhibiting E2F Transcription Factor 1-mediated MNX1 antisense RNA 1

Increasing evidence has shown that traditional Chinese medicines and their bioactive components exert an anti-tumor effect, representing a novel treatment strategy. Actinidia chinensis Planch Root extracts (acRoots) have been reported to repress cancer cell proliferation and metastasis. The effect of acRoots on hypopharyngeal carcinoma progression was explored in this study. Firstly, data from MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and colony formation assays showed that incubation with accRoots reduced cell proliferation of hypopharyngeal carcinoma cells. Moreover, acRoots promoted the cell apoptosis of hypopharyngeal carcinoma. Secondly, cell migration and invasion of hypopharyngeal carcinoma cells were suppressed by acRoots. Thirdly, E2F1 (E2F Transcription Factor 1) and lncRNA MNX1-AS1 (MNX1 antisense RNA 1) were up-regulated in hypopharyngeal carcinoma tissues, and reduced in hypopharyngeal carcinoma cells post acRoots incubation. Overexpression of E2F1 attenuated acRoots-induced decrease in MNX1-AS1 in hypopharyngeal carcinoma cells. Lastly, administration with acRoots retarded in vivo hypopharyngeal carcinoma growth through down-regulation of E2F1-mediated MNX1-AS1. In conclusion, acRoots exerted tumor-suppressive role in hypopharyngeal carcinoma through inhibition of E2F1-mediated MNX1-AS1.