LncRNA MALAT1 exhibits positive effects on nucleus pulposus cell biology in vivo and in vitro by sponging miR-503

2020 ◽  
Author(s):  
Hongyu Zheng ◽  
Tingting Wang ◽  
Xiangmin Li ◽  
Wei He ◽  
Zhiqiang Gong ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Disc Degeneration ◽  
Cell Biology ◽  
Mapk Pathway ◽  
Critical Role ◽  
Mapk Signaling ◽  
Positive Effects ◽  
Lncrna Malat1

Abstract Background: Intervertebral disc degeneration (IDD) is characterized by the loss of nucleus pulposus cells (NPCs) and phenotypic abnormalities. Accumulating evidence suggests that long noncoding RNAs (lncRNAs) are involved in the pathogenesis of IDD. In this study, we aimed to investigate the functional effects of lncRNA MALAT1 on NPCs in IDD and the possible mechanism governing these effects. Results: We validated the decreased expression of MALAT1 in the IDD tissues, which was associated with decreased Collagen II and Aggrecan expression. In vitro, overexpressed MALAT1 could attenuate the effect of IL-1β on NPC proliferation, apoptosis, and Aggrecan degradation. In vivo, MALAT1 overexpression attenuated the severity of disc degeneration in IDD model rats. Our molecular study further demonstrated that MALAT1 could sponge miR-503, modulate the expression of miR-503, and activate downstream MAPK signaling pathways. The effects of MALAT1 on NPCs were partially reversed/aggregated by miR-503 mimics/inhibitor treatment. Conclusion: Our data suggested that the MALAT1-miR-503-MAPK pathway plays a critical role in NPCs, which may be a potential strategy for alleviating IDD.

LncRNA MALAT1 exhibits positive effects on nucleus pulposus cells biology in vivo and in vitro by sponging miR-503 media the P38MAPKs/AP-1 pathway

2019 ◽  
Author(s):  
Hongyu Zheng ◽  
Tingting Wang ◽  
Xiangmin Li ◽  
Wei He ◽  
Zhiqiang Gong ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Disc Degeneration ◽  
Mapk Pathway ◽  
Critical Role ◽  
Molecular Study ◽  
Mapk Signaling ◽  
Nucleus Pulposus Cells ◽  
Positive Effects

Abstract Background: Intervertebral disc degeneration (IDD) is characterized by the loss of nucleus pulposus cells (NPCs) and phenotypic abnormalities. Accumulated evidence suggests that long non-coding RNAs (lncRNAs) are involved in the pathogenesis of IDD. In this study, we aimed to investigate the functional effects of lncMALAT1 on NPCs in IDD and the possible mechanism. Results: We validated the decreased expression of MALAT1 in the IDD tissues, associating with increased collagen II and aggrecan expression. In vitro, overexpressed MALAT1 could attenuate the effect of IL-1β on NPCs proliferation, apoptosis, and aggrecan degradation. In vivo, MALAT1 overexpression attenuated the severity of disc degeneration in IDD model rats. Our molecular study further demonstrated that MALAT1 could sponge miR-503, modulate the expression of miR-503, and the activation of downstream MAPK signaling pathways. The effects of MALAT1 on NPCs were partially reversed/ aggregated by miR-503 mimics/inhibitor treatment. Conclusion: Our data suggested that MALAT1-miR-503-MAPK pathway plays a critical role in NPCs, which may be a potential strategy for improving IDD.

scholarly journals LncRNA MALAT1 exhibits positive effects on nucleus pulposus cell biology in vivo and in vitro by sponging miR-503

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Hongyu Zheng ◽  
Tingting Wang ◽  
Xiangmin Li ◽  
Wei He ◽  
Zhiqiang Gong ◽  
...  
Keyword(s):  
Nucleus Pulposus ◽  
Cell Biology ◽  
Nucleus Pulposus Cell ◽  
Positive Effects ◽  
Lncrna Malat1

scholarly journals CGRP Regulates Nucleus Pulposus Cell Apoptosis and Inflammation via the MAPK/NF-κB Signaling Pathways during Intervertebral Disc Degeneration

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Kaiqiang Sun ◽  
Jian Zhu ◽  
Chen Yan ◽  
Fudong Li ◽  
Fanqi Kong ◽  
...  
Keyword(s):  
Intervertebral Disc ◽  
Signaling Pathways ◽  
Nucleus Pulposus ◽  
Disc Degeneration ◽  
Intervertebral Disc Degeneration ◽  
Nucleus Pulposus Cell ◽  
Mapk Signaling ◽  
Discogenic Pain

Chronic low back pain (CLBP) has been proved to be the dominating cause of disability in patients with lumbar degenerative diseases. Of the various etiological factors, intervertebral disc degeneration (IVDD) has been the dominating cause. In the past few decades, the role and changes of nerve systems, especially the peripheral sensory fibers and their neurotransmitters, in the induction and progression of IVDD have attracted growing concerns. The expression of many neuropeptides, such as SP, NPY, and CGRP, in the nociceptive pathways is increased during the progression of IVDD and responsible for the discogenic pain. Here, the role of CGRP in the progression of IVDD was firstly investigated both in vitro and in vivo. Firstly, we confirmed that human degenerated intervertebral disc tissue exhibited elevated expression of CGRP and its receptor. Secondly, in vitro experiments suggested that CGRP could inhibit the proliferation and induce apoptosis in human nucleus pulposus (NP) cells, as well as promote inflammation and degenerated phenotypes through activating NF-κB and MAPK signaling pathways. Thirdly, CGRP receptor antagonist, Rimegepant, can ameliorate the adverse effects of CGRP imposed on NP cells, which were confirmed in vitro and in vivo. Our results will bring about a brand-new insight into the roles of neuromodulation in IVDD and related therapeutic attempts.

scholarly journals Targeting Rad51 as a strategy for the treatment of melanoma cells resistant to MAPK pathway inhibition

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Elena Makino ◽  
Lisa Marie Fröhlich ◽  
Tobias Sinnberg ◽  
Corinna Kosnopfel ◽  
Birgit Sauer ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Metastatic Melanoma ◽  
Mapk Pathway ◽  
Critical Role ◽  
Melanoma Cells ◽  
Mapk Signaling ◽  
Transcriptional Level ◽  
Mapk Inhibitor

Abstract Rad51 is an essential factor of the homologous recombination DNA repair pathway and therefore plays an important role in maintaining genomic stability. We show that RAD51 and other homologous recombination repair genes are overexpressed in metastatic melanoma cell lines and in melanoma patient samples, which correlates with reduced survival of melanoma patients. In addition, Rad51 expression in melanoma cells was regulated on a transcriptional level by the MAPK signaling pathway with Elk1 as the main downstream transcriptional effector. Most strikingly, melanoma cells which developed resistance towards MAPK inhibitors could be efficiently targeted by Rad51 inhibitors similar to their sensitive counterparts, leading to DNA damage, G2/M arrest and apoptosis. Furthermore, the treatment of MAPK inhibitor resistant cells with Rad51 inhibitors enhances the susceptibility of these cells for MAPK inhibitor treatment in vitro and in vivo. These data indicate that Rad51 plays a critical role in the survival of metastatic melanoma cells and is a promising target for the therapy of melanoma irrespective of its MAPK inhibitor resistance status.

scholarly journals Critical role of the extracellular signal–regulated kinase–MAPK pathway in osteoblast differentiation and skeletal development

2007 ◽  
Vol 176 (5) ◽  
pp. 709-718 ◽  
Author(s):  
Chunxi Ge ◽  
Guozhi Xiao ◽  
Di Jiang ◽  
Renny T. Franceschi
Keyword(s):  
Transcriptional Activity ◽  
Mapk Pathway ◽  
Skeletal Development ◽  
Critical Role ◽  
Dominant Negative ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal

The extracellular signal–regulated kinase (ERK)–mitogen-activated protein kinase (MAPK) pathway provides a major link between the cell surface and nucleus to control proliferation and differentiation. However, its in vivo role in skeletal development is unknown. A transgenic approach was used to establish a role for this pathway in bone. MAPK stimulation achieved by selective expression of constitutively active MAPK/ERK1 (MEK-SP) in osteoblasts accelerated in vitro differentiation of calvarial cells, as well as in vivo bone development, whereas dominant-negative MEK1 was inhibitory. The involvement of the RUNX2 transcription factor in this response was established in two ways: (a) RUNX2 phosphorylation and transcriptional activity were elevated in calvarial osteoblasts from TgMek-sp mice and reduced in cells from TgMek-dn mice, and (b) crossing TgMek-sp mice with Runx2+/− animals partially rescued the hypomorphic clavicles and undemineralized calvaria associated with Runx2 haploinsufficiency, whereas TgMek-dn; Runx2+/− mice had a more severe skeletal phenotype. This work establishes an important in vivo function for the ERK–MAPK pathway in bone that involves stimulation of RUNX2 phosphorylation and transcriptional activity.

scholarly journals Hydroxychloroquine Synergizes With The PI3K Inhibitor BKM120 to Exhibit Antitumor Efficacy Independent of Autophagy

2021 ◽  
Author(s):  
Xin Peng ◽  
Shaolu Zhang ◽  
Wenhui Jiao ◽  
Zhenxing Zhong ◽  
Yuqi Yang ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Cell Biology ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Single Agent ◽  
Antitumor Efficacy ◽  
Antitumor Effects ◽  
Autophagy Inhibitor

Abstract Background: The critical role of phosphoinositide 3-kinase (PI3K) activation in tumor cell biology has prompted massive efforts to develop PI3K inhibitors (PI3Kis) for cancer therapy. However, recent results from clinical trials have shown only a modest therapeutic efficacy of single-agent PI3Kis in solid tumors. Targeting autophagy has controversial context-dependent effects in cancer treatment. As a FDA-approved lysosomotropic agent, hydroxychloroquine (HCQ) has been well tested as an autophagy inhibitor in preclinical models. Here, we elucidated the novel mechanism of HCQ alone or in combination with PI3Ki BKM120 in the treatment of cancer.Methods: The antitumor effects of HCQ and BKM120 on three different types of tumor cells were assessed by in vitro PrestoBlue assay, colony formation assay and in vivo zebrafish and nude mouse xenograft models. The involved molecular mechanisms were investigated by MDC staining, LC3 puncta formation assay, immunofluorescent assay, flow cytometric analysis of apoptosis and ROS, qRT-PCR, Western blot, comet assay, homologous recombination (HR) assay and immunohistochemical staining. Results: HCQ significantly sensitized cancer cells to BKM120 in vitro and in vivo. Interestingly, the sensitization mediated by HCQ could not be phenocopied by treatment with other autophagy inhibitors (Spautin-1, 3-MA and bafilomycin A1) or knockdown of the essential autophagy genes Atg5/Atg7, suggesting that the sensitizing effect might be mediated independent of autophagy status. Mechanistically, HCQ induced ROS production and activated the transcription factor NRF2. In contrast, BKM120 prevented the elimination of ROS by inactivation of NRF2, leading to accumulation of DNA damage. In addition, HCQ activated ATM to enhance HR repair, a high-fidelity repair for DNA double-strand breaks (DSBs) in cells, while BKM120 inhibited HR repair by blocking the phosphorylation of ATM and the expression of BRCA1/2 and Rad51. Conclusions: Our study revealed that HCQ and BKM120 synergistically increased DSBs in tumor cells and therefore augmented apoptosis, resulting in enhanced antitumor efficacy. Our findings provide a new insight into how HCQ exhibits antitumor efficacy and synergizes with PI3Ki BKM120, and warn that one should consider the “off target” effects of HCQ when used as autophagy inhibitor in the clinical treatment of cancer.

Effect of bypass kinase pathways on acquired CDK4/6 inhibitor resistance.

2018 ◽  
Vol 36 (6_suppl) ◽  
pp. 379-379
Author(s):  
Renee De Leeuw ◽  
Christopher McNair ◽  
Matthew Joseph Schiewer ◽  
Neermala Poudel Neupane ◽  
Michael Augello ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Early Stage ◽  
Mapk Signaling ◽  
Cross Resistance ◽  
Mek Inhibitors ◽  
Mesenchymal Transition ◽  
Inhibitor Resistance ◽  
Tumor Types

379 Background: Cyclin Dependent Kinase-4/6 (CDK4/6) kinase inhibitors have shown clinical benefit in treatment of solid tumor types, including breast cancer. However, resistance is common, and the underpinning mechanisms of action are not well understood. Given the dependence of CDK4/6 inhibitors on retinoblastoma tumor suppressor (RB) function for activity, this class of agents may be particularly effective in tumor types for which RB loss is infrequent or occurs late in tumor progression. Methods: Here, models of acquired palbociclib resistance were generated in early stage, RB positive cancers, wherein it was shown acquired palbociclib resistance resulted in cross-resistance to other CDK4/6 inhibitors under clinical testing. Results: Cells showing acquired resistance exhibited aggressive in vitro and in vivo phenotypes without genetic loss of RB or RB pathway members, including enhanced proliferative capacity, migratory potential, and characteristics of epithelial to mesenchymal transition. Further analyses through integration of RNA sequencing and phospho-proteomics identified activation of the MAPK signaling pathway as a mediator of CDK4/6 inhibitor resistance, capable of bypassing CDK4/6 activity. However, this altered kinase dependence resulted in sensitization to MEK inhibitors, suggestive of new clinical opportunities in CDK4/6 resistant tumors. Conclusions: In sum, the studies herein not only identify activation of the MAPK pathway as capable of bypassing the CDK4/6 requirement and promoting aggressive tumor characteristics, but nominate MEK inhibitors as potential mechanisms to treat or prevent CDK4/6 inhibitor resistance.

scholarly journals Anti-Tumor Activity of ASTX029, a Dual Mechanism Inhibitor of ERK1/2, in Preclinical AML Models

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 7-8
Author(s):  
Christopher J. Hindley ◽  
Lynsey Fazal ◽  
Joanne M. Munck ◽  
Vanessa Martins ◽  
Alpesh D. Shah ◽  
...  
Keyword(s):  
Cell Lines ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Activating Mutations ◽  
Ic50 Value ◽  
Ras Family ◽  
Dual Mechanism ◽  
Anti Tumor Activity

Oncogenic mutations in genes such as the RAS family (KRAS, NRAS or HRAS) or receptor tyrosine kinases (RTKs) drive tumor growth through aberrant activation of the mitogen activated protein kinase (MAPK) signaling pathway. Acute myeloid leukemia (AML) patients frequently exhibit activating mutations in MAPK pathway members, such as NRAS and KRAS, suggesting that these malignancies may be driven by aberrant activation of the MAPK pathway. Targeting of the MAPK pathway has been clinically validated in solid tumors, with agents targeting BRAF and MEK approved for the treatment of BRAF-mutant melanoma. However, there is currently no approved therapy directly targeting activated RAS family members and resistance to MAPK pathway inhibitors is frequently associated with reactivation of MAPK signaling. ERK1/2 (ERK) is a downstream node in the MAPK pathway and therefore represents an attractive therapeutic target for inhibition of MAPK signaling in these settings. We have recently described in vivo anti-tumor activity in MAPK-activated solid tumor models following treatment with ASTX029, a highly potent ERK inhibitor developed using fragment-based drug design. ASTX029 has a distinctive ERK binding mode which confers dual mechanism inhibition of ERK, inhibiting both the catalytic activity of ERK and its phosphorylation by MEK. Here, we demonstrate that ASTX029 is also active in AML models and potently inhibits in vitro and in vivo MAPK signaling and growth in these models. Using a panel of 15 AML cell lines, we investigated sensitivity to ASTX029 in vitro. We observed that 8 cell lines bearing mutations leading to increased MAPK pathway signaling were sensitive to treatment with ASTX029 with an average IC50 value of 47 nM, in contrast to an average IC50 value of 1800 nM for cell lines without activating mutations. The phosphorylation of RSK, a direct substrate of ERK, was suppressed for up to 24 h following treatment with ASTX029 in vitro. We have previously demonstrated good oral bioavailability for ASTX029 and once daily dosing resulted in significant tumor growth inhibition in AML cell line xenograft models. To confirm target engagement in vivo, we examined MAPK signaling in xenograft tissue and observed inhibition of the phosphorylation of RSK and of ERK itself, consistent with the dual mechanism of action proposed for ASTX029. In summary, the ERK inhibitor, ASTX029, has potent activity against MAPK-activated tumor models, including AML models, and is now being tested in a Phase 1/2 clinical trial in advanced solid tumors (NCT03520075). These data highlight its therapeutic potential for the treatment of AML in patients with mutations leading to MAPK pathway activation and support further investigation in these patient populations. Disclosures Hindley: Astex Pharmaceuticals: Current Employment. Fazal:Astex Pharmaceuticals: Current Employment. Munck:Astex Pharmaceuticals: Current Employment. Martins:Astex Pharmaceuticals: Current Employment. Shah:Astex Pharmaceuticals: Current Employment. Wilsher:Astex Pharmaceuticals: Current Employment. Wallis:Astex Pharmaceuticals: Current Employment. Keer:Astex Pharmaceuticals, Inc.: Current Employment. Lyons:Astex Pharmaceuticals: Current Employment.

scholarly journals MEK-inhibitor-mediated rescue of skeletal myopathy caused by activating Hras mutation in a Costello syndrome mouse model

2021 ◽  
Author(s):  
William E. Tidyman ◽  
Alice F. Goodwin ◽  
Yoshiko Maeda ◽  
Ophir D. Klein ◽  
Katherine A. Rauen
Keyword(s):  
Mouse Model ◽  
Mapk Pathway ◽  
Mek Inhibitor ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Costello Syndrome ◽  
Skeletal Myopathy ◽  
Mitogen Activated Protein

Costello syndrome (CS) is a congenital disorder caused by heterozygous activating germline HRAS mutations in the canonical Ras/mitogen-activated protein kinase (Ras/MAPK) pathway. CS is one of the RASopathies, a large group of syndromes due to mutations within various components of the Ras/MAPK pathway. An important part of the phenotype that greatly impacts quality of life is hypotonia. To gain a better understanding of the mechanisms underlying hypotonia in CS, a mouse model with an activating HrasG12V allele was utilized. We identified a skeletal myopathy that was due in part to an inhibition of embryonic myogenesis and myofiber formation, resulting in a reduction of myofiber size and number that led to reduced muscle mass and strength. In addition to hyperactivation of the Ras/MAPK and PI3K/AKT pathways, there was a significant reduction of p38 signaling, as well as global transcriptional alterations consistent with the myopathic phenotype. Inhibition of Ras/MAPK pathway signaling using a MEK inhibitor rescued the HrasG12V myopathy phenotype both in vitro and in vivo, demonstrating that increased MAPK signaling is the main cause of the muscle phenotype in CS.

scholarly journals tRNA-Derived Fragment tRF-Glu-TTC-027 Regulates the Progression of Gastric Carcinoma via MAPK Signaling Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Weiguo Xu ◽  
Bin Zhou ◽  
Juan Wang ◽  
Li Tang ◽  
Qing Hu ◽  
...  
Keyword(s):  
Gastric Carcinoma ◽  
Signaling Pathway ◽  
Cell Lines ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Mapk Signaling Pathway ◽  
Migration And Invasion ◽  
Underlying Mechanisms

Transfer RNA-derived RNA fragments (tRFs) belong to non-coding RNAs (ncRNAs) discovered in most carcinomas. Although some articles have demonstrated the characteristics of tRFs in gastric carcinoma (GC), the underlying mechanisms still need to be elucidated. Meanwhile, it was reported that the MAPK pathway was momentous in GC progression. Thus we focused on investigating whether tRF-Glu-TTC-027 could act as a key role in the progression of GC with the regulation of the MAPK pathway. We collected the data of the tRNA-derived fragments expression profile from six paired clinical GC tissues and corresponding adjacent normal samples in this study. Then we screened tRF-Glu-TTC-027 for analysis by using RT-PCR. We transfected GC cell lines with tRF-Glu-TTC-027 mimics or mimics control. Then the proliferation, migration, and invasion assays were performed to assess the influence of tRF-Glu-TTC-027 on GC cell lines. Fluorescence in situ hybridization assay was conducted to confirm the cell distribution of tRF-Glu-TTC-027. We confirmed the mechanism that tRF-Glu-TTC-027 influenced the MAPK signaling pathway and observed a strong downregulation of tRF-Glu-TTC-027 in clinical GC samples. Overexpression of tRF-Glu-TTC-027 suppressed the malignant activities of GC in vitro and in vivo. MAPK signaling pathway was confirmed to be a target pathway of tRF-Glu-TTC-027 in GC by western blot. This is the first study to show that tRF-Glu-TTC-027 was a new tumor-suppressor and could be a potential object for molecular targeted therapy in GC.

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