PIM2 Pro-Survival Functions Are Mediated By RSK2 in AML

Abstract Acute myeloid leukemia (AML) with FLT3 internal tandem duplication (FLT3-ITD) is a poor prognosis hematologic malignancy accounting for 30% of AML cases. Constitutive FLT3-ITD activation drives STAT5 signaling resulting in enhanced PIM kinases expression. PIM serine/threonine kinases (including PIM1,-2,-3) are involved in cell cycle and apoptosis regulation and thus represent emerging therapeutic targets. We previously reported an increased PIM2 protein expression in primary AML cells compared to normal CD34+ immature hematopoietic cells. Here, we aimed to study PIM kinases as potential therapeutic target in FLT3-ITD AML. In two distinct FLT3-ITD+ human AML cell lines (MV4-11 and MOLM-14) doxycycline (Dox)-induced shRNA-mediated PIM2 knockdown enhanced apoptosis, attested by an increase in early apoptotic (annexin V positive, DAPI negative) and late apoptotic (both annexin V, DAPI positive) cells. Cell death upon PIM2 knockdown was confirmed by an inhibition of colony formation in methylcellulose. Mechanisms of apoptosis induction involved release of second mitochondria-derived activator of caspases (SMAC) as well as increased p53 and Bax expression and Bax nuclear translocation, leading to loss of mitochondrial membrane potential. To gain further mechanistic insights, we performed global gene expression profiling in the MOLM-14 cell line lentivirally transduced with Dox-inducible PIM2 shRNA. Consistent with our functional analysis, cell-cycle regulatory genes (including c-MYC, CHK1 or PLK1) and pro-survival genes (including RSK2 or BCL2) were down-regulated, while pro-apoptotic genes (most notably TP53 and BAX) were up-regulated. Here we focused on RSK2, a member of the mitogen-activated protein kinase (MAPK) signaling pathway that has not been previously reported to be a target of PIM2. In the MOLM-14 cell line, PIM2 knockdown reduced RSK2 mRNA and protein levels. RSK2 knockdown using a Dox-inducible RSK2 shRNA induced apoptosis similarly to that observed following PIM2 knockdown in this cell line. In parallel with PIM2 knockdown, RSK2 down-regulation enhanced p53 expression and activity, as measured by increased expression of its transcriptional target p21, as well as Bax expression. In summary, our results suggest that RSK2 is a PIM2 transcriptional target that contributes to PIM-2-dependent cell survival mediated by a novel RSK2-p53-Bax signaling pathway. RSK2 therefore warrants further study as a potential pharmacologic target in AML (particularly in cases resistant to PIM inhibition) as well as other PIM-addicted malignancies. Disclosures No relevant conflicts of interest to declare.

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Simultaneous Inhibition of Mcl-1 and XIAP To Induce Apoptosis in AML Cells.

Blood ◽

10.1182/blood.v106.11.1520.1520 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1520-1520

Author(s):

Bing Z. Carter ◽

Duncan Mak ◽

Wendy Schober ◽

Erich Koller ◽

Nicholas M. Dean ◽

...

Keyword(s):

Cell Cycle ◽

Cell Death ◽

Signaling Pathway ◽

Antisense Oligonucleotide ◽

Annexin V ◽

Mapk Signaling ◽

Caspase Inhibitor ◽

Caspase Activation ◽

Simultaneous Inhibition ◽

Apoptotic Cascade

Abstract The apoptotic cascade is regulated by both upstream Bcl-2 and the distal IAP family proteins. Mcl-1, a member of antiapoptotic Bcl-2 family proteins is highly expressed in various cancer cells. It was reported that its expression is elevated at the time of leukemic relapse (Blood1998;19:991–1000). XIAP, the most potent cellular caspase inhibitor, inhibits both the initiator caspase-9 and the effector caspase-3 and suppresses apoptosis. Our previous study showed that decrease of XIAP by its antisense oligonucleotide enhances Ara-C-induced apoptosis (Leukemia2003;17:2081–2089). In this study, we investigated the regulation of Mcl-1 expression, its potential as a therapeutic target, and apoptosis induction by simultaneous inhibition of Mcl-1 and XIAP in AML cells. We found that like survivin, Mcl-1 protein level is decreased by MEK inhibition in HL-60 and OCI-AML2 cells suggesting that Mcl-1 expression is regulated through the MAPK signaling pathway. However, in contrast to survivin levels, no significant differences in Mcl-1 expression in G0/G1, S, and G2M cells were observed in FACS-sorted HL-60 cells. Downregulation of Mcl-1 by its antisense oligonucleotide (Mcl-1-AS, 20408, ISIS Pharmaceuticals) induced cell death accompanied by decrease in mitochondrial membrane potential (MMP), caspase activation and annexin V positivity in HL-60 cells, while control oligonucleotide was not toxic. By itself, MEK inhibitor primarily induced G1/G0 cell cycle block and no apoptosis. When combined with Mcl-1-AS, MEK inhibition further decreased Mcl-1 protein levels and significantly increased Mcl-1-AS induced cell death (from 25.8±1.3% to 40±3.8%, p=0.02). Inhibition of XIAP by its antisense oligonucleotide (XIAP-AS, 102369, ISIS Pharmaceuticals) did not induce significant loss of MMP at 24 hrs and slightly increased annexin V positive cells at 48 hrs (14.5%±2.9% dead cells vs. 6.2%±0.72% in XIAP-NS treated cells). However, when combined with Mcl-1 inhibition, significant increases in loss of MMP at 24 hrs and annexin V positive cells at 48 hrs (p=0.003), more than inhibition of each protein alone, was observed indicating that activating the upstream and downstream apoptotic cascade will amplify the caspase activation loop and more efficiently induce cell death. Our study suggests that Mcl-1 is regulated by the MAPK signaling pathway. Its expression is cell cycle independent. Mcl-1 is essential for HL-60 cell survival and simultaneously downregulation of the upstream anti-apoptotic protein Mcl-1 and the downstream caspase inhibitor XIAP significantly enhances leukemia cell apoptosis.

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RIG-I acts as a tumor suppressor in melanoma via regulating the activation of MKK/p38MAPK signaling pathway

10.21203/rs.3.rs-758070/v1 ◽

2021 ◽

Author(s):

Rui Guo ◽

Shun-Yuan Lu ◽

Jin-Xia Ma ◽

Qian-Lan Wang ◽

Lu Zhang ◽

...

Keyword(s):

Cell Cycle ◽

Tumor Suppressor ◽

Cell Line ◽

Signaling Pathway ◽

P38 Mapk ◽

Melanoma Cell ◽

Melanoma Cell Line ◽

Mapk Signaling ◽

Phase Cell ◽

Brdu Incorporation

Abstract Background Studies have indicated that RIG-I may act as a tumor suppressor and participate in the tumorigenesis of some malignant diseases. However, RIG-I induces distinct cellular responses via different downstream signaling pathways depending on the cell type. The aim of this study was to investigate the biological function and underlying molecular mechanism of RIG-I in the tumorigenesis of melanoma. Methods We conducted RIG-I knockout and RIG-I overexpressing B16-F10 melanoma cell line, and further analyzed the RIG-I mediated change of tumor biology behaviors in spontaneous and poly I:C induced RIG-I activation status. Cell proliferation, cell cycle, apoptosis and migration were detected by CCK-8 assay, BrdU incorporation, Annexin V-PI staining assay and transwell assay, respectively. In vivo tumorigenicity was evaluated by tumor xenograft growth in nude mice and subsequently Ki67 staining and TUNEL assay. Furthermore, Western blot was utilized to explore the underlying mechanism of RIG-I in melanoma cells. Results Our data showed that RIG-I promotes the apoptosis and inhibits the proliferation by G1 phase cell-cycle arrest in B16-F10 melanoma cell line. Mechanically, RIG-I could induce the phosphorylation level of p38 MAPK and MAPK kinase MKK3/MKK4. Conclusion The current study demonstrated that RIG-I suppressed the development of melanoma via regulating the activity of MKK/p38 MAPK signaling pathway, which will be useful in the research of novel therapeutic targets for this malignant disease.

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Inhibition of the PERK-Dependent Unfolded Protein Response Signaling Pathway Involved in the Pathogenesis of Alzheimer’s Disease

Current Alzheimer Research ◽

10.2174/1567205016666190228121157 ◽

2019 ◽

Vol 16 (3) ◽

pp. 209-218 ◽

Cited By ~ 4

Author(s):

Wioletta Rozpędek ◽

Dariusz Pytel ◽

Tomasz Popławski ◽

Anna Walczak ◽

Kinga Gradzik ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Cell Cycle ◽

Unfolded Protein Response ◽

Cell Line ◽

Signaling Pathway ◽

Cell Cycle Progression ◽

Annexin V ◽

Cycle Progression ◽

Unfolded Protein ◽

Protein Response

<P>Objectives: There is a body of evidence that neurodegenerative disease entities are directly correlated with the perturbations on the molecular level. Hence, the ER stress-mediated Unfolded Protein Response (UPR) is activated resulting in PERK-dependent phosphorylation of the Eukaryotic initiation factor 2 (eIF2α). Thus, the levels of ATF4 and CHOP proteins are significantly increased, which subsequently switches the pro-adaptive branch of the UPR into the pro-apoptotic directly leading to neuronal loss and initiation of the neurodegenerative process. The aim of the presented study was the evaluation of the biological activity of highly specific, small-molecule inhibitors of the PERKdependent UPR signaling pathway. Methods: The study was conducted on rat astrocytic DI TNC1 cell line. The level of p-eIF2α was measured by Western blot technique, the cytotoxicity of the investigated compound was assessed by the MTT assay and using the FITC-conjugated Annexin V (Annexin V-FITC) to indicate apoptosis and propidium iodide (PI) to indicate necrosis. The effect of tested compound on cell cycle progression was measured by flow cytometry, where the PI-labelled nuclei were analysed for DNA content. Results: As a result one of the investigated compound LDN-0060609 triggers a significant inhibition of the eIF2α phosphorylation in DI TNC1 cell line. Moreover, we showed that compound LDN-0060609 is non-cytotoxic and has no effect on cell cycle progression. Conclusion: In conclusion, LDN-0060609 may constitute a novel, targeted treatment approach against neurodegenerative diseases, including Alzheimer’s disease (AD), where pathogenesis and progression are closely associated with the overactivation of the PERK-dependent UPR signaling pathway.

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Design, Synthesis and In Vitro Anti-Cancer Evaluation of Novel Derivatives of 2-(2-Methyl-1,5-diaryl-1H-pyrrol-3-yl)-2-oxo-N-(pyridin-3- yl)acetamide

Medicinal Chemistry ◽

10.2174/1573406415666190425153717 ◽

2020 ◽

Vol 16 (3) ◽

pp. 340-349

Author(s):

Ebrahim S. Moghadam ◽

Farhad Saravani ◽

Ernest Hamel ◽

Zahra Shahsavari ◽

Mohsen Alipour ◽

...

Keyword(s):

Cell Cycle ◽

Peripheral Neuropathy ◽

Cell Line ◽

Normal Cell ◽

Caspase 3 ◽

Annexin V ◽

Normal Cell Line ◽

Anti Cancer ◽

Mcf 7

Objective: Several anti-tubulin agents were introduced for the cancer treatment so far. Despite successes in the treatment of cancer, these agents cause toxic side effects, including peripheral neuropathy. Comparing anti-tubulin agents, indibulin seemed to cause minimal peripheral neuropathy, but its poor aqueous solubility and other potential clinical problems have led to its remaining in a preclinical stage. Methods: Herein, indibulin analogues were synthesized and evaluated for their in vitro anti-cancer activity using MTT assay (on the MCF-7, T47-D, MDA-MB231 and NIH-3T3 cell lines), annexin V/PI staining assay, cell cycle analysis, anti-tubulin assay and caspase 3/7 activation assay. Results: One of the compounds, 4a, showed good anti-proliferative activity against MCF-7 cells (IC50: 7.5 μM) and low toxicity on a normal cell line (IC50 > 100 μM). All of the tested compounds showed lower cytotoxicity on normal cell line in comparison to reference compound, indibulin. In the annexin V/PI staining assay, induction of apoptosis in the MCF-7 cell line was observed. Cell cycle analysis illustrated an increasing proportion of cells in the sub-G-1 phase, consistent with an increasing proportion of apoptotic cells. No increase in G2/M cells was observed, consistent with the absence of anti-tubulin activity. A caspase 3/7 assay protocol showed that apoptosis induction by more potent compounds was due to activation of caspase 3. Conclusion: Newly synthesized compounds exerted acceptable anticancer activity and further investigation of current scaffold would be beneficial.

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Andrographolide Inhibits Proliferation of Colon Cancer SW-480 Cells via Downregulating Notch Signaling Pathway.

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520620666200717143109 ◽

2020 ◽

Vol 20 ◽

Author(s):

Imran Khan ◽

Sadaf Mahfooz ◽

Mohd Saeed ◽

Irfan Ahmad ◽

Irfan A. Ansari

Keyword(s):

Cell Cycle ◽

Colon Cancer ◽

Notch Signaling ◽

Signaling Pathway ◽

Mtt Assay ◽

Annexin V ◽

Notch Signaling Pathway ◽

Phase Cell ◽

Ros Generation ◽

Notch 1

Background: Recently Notch signaling pathway has gained attention as a potential therapeutic target for chemotherapeutic intervention. However, the efficacy of previously known Notch inhibitors in colon cancer is still unclear. The purpose of this study was to investigate the effect of andrographolide on aberrantly activated Notch signaling in SW-480 cells in vitro. Methods: The cytostatic potential of andrographolide on SW-480 cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay, morphology assessment and colony formation assay. The apoptotic activity was evaluated by FITC Annexin V assay, 4′,6-diamidino-2-phenylindole (DAPI), Hoechst, Rhodamine 123 and Mito Tracker CMXRos staining. Scratch assay for migratory potential assessment. 7’-Dichlorodihydrofluorescein Diacetate (DCFH-DA) staining was used to evaluate the Reactive Oxygen Species (ROS) generation. Relative mRNA expression of Bax, Bcl2, NOTCH 1 and JAGGED 1 was estimated by Real-Time Quantitative Reverse Transcription PCR (qRT-PCR). Cell cycle phase distribution was evaluated Annexin V-FITC/PI staining. Results: MTT assay demonstrated dose and time dependent cytoxicity of andrographolide on SW-480 cells. It also inhibited the migratory and colony forming potential of SW-480 cells. Furthermore, andrographolide also showed disruption of mitochondrial membrane potential and induced apoptosis through nuclear condensation. Flow cytometric evaluation showed andrographolide enhanced early and late apoptotic cells and induced upregulation of proapoptotic (Bax and Bad) and downregulation of antiapoptotic Bcl2 in treated SW-480 cells. Andrographolide augmented intracellular ROS generation and induced G0/G1 phase cell cycle arrest in colon cancer SW480 cells. Furthermore, andrographolide repressed the Notch signaling by decreasing the expression of NOTCH 1 and JAGGED 1. Conclusion: Our findings suggested that andrographolide constraint the growth of SW-480 cells through the inhibition of Notch signaling pathway.

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Involvement of the p38 MAPK signaling pathway in S-phase cell-cycle arrest induced by Furazolidone in human hepatoma G2 cells

Journal of Applied Toxicology ◽

10.1002/jat.2829 ◽

2012 ◽

Vol 33 (12) ◽

pp. 1500-1505 ◽

Cited By ~ 6

Author(s):

Yu Sun ◽

Shusheng Tang ◽

Xi Jin ◽

Chaoming Zhang ◽

Wenxia Zhao ◽

...

Keyword(s):

Cell Cycle ◽

Cell Cycle Arrest ◽

Signaling Pathway ◽

P38 Mapk ◽

Mapk Signaling ◽

S Phase ◽

Mapk Signaling Pathway ◽

Phase Cell ◽

Human Hepatoma ◽

Cycle Arrest

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Spirulina Crude Protein Promotes the Migration and Proliferation in IEC-6 Cells by Activating EGFR/MAPK Signaling Pathway

Marine Drugs ◽

10.3390/md17040205 ◽

2019 ◽

Vol 17 (4) ◽

pp. 205

Author(s):

Su-Jin Jeong ◽

Jeong-Wook Choi ◽

Min-Kyeong Lee ◽

Youn-Hee Choi ◽

Taek-Jeong Nam

Keyword(s):

Cell Cycle ◽

Epithelial Cells ◽

Signaling Pathway ◽

Crude Protein ◽

Cell Cycle Progression ◽

Intestinal Epithelial Cells ◽

Mapk Signaling ◽

S Phase ◽

Intestinal Epithelial ◽

Cycle Progression

Spirulina is a type of filamentous blue-green microalgae known to be rich in nutrients and to have pharmacological effects, but the effect of spirulina on the small intestine epithelium is not well understood. Therefore, this study aims to investigate the proliferative effects of spirulina crude protein (SPCP) on a rat intestinal epithelial cells IEC-6 to elucidate the mechanisms underlying its effect. First, the results of wound-healing and cell viability assays demonstrated that SPCP promoted migration and proliferation in a dose-dependent manner. Subsequently, when the mechanisms of migration and proliferation promotion by SPCP were confirmed, we found that the epidermal growth factor receptor (EGFR) and mitogen-activated protein (MAPK) signaling pathways were activated by phosphorylation. Cell cycle progression from G0/G1 to S phase was also promoted by SPCP through upregulation of the expression levels of cyclins and cyclin-dependent kinases (Cdks), which regulate cell cycle progression to the S phase. Meanwhile, the expression of cyclin-dependent kinase inhibitors (CKIs), such as p21 and p27, decreased with SPCP. In conclusion, our results indicate that activation of EGFR and its downstream signaling pathway by SPCP treatment regulates cell cycle progression. Therefore, these results contribute to the research on the molecular mechanism for SPCP promoting the migration and proliferation of rat intestinal epithelial cells.

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Proposed megakaryocytic regulon of p53: the genes engaged to control cell cycle and apoptosis during megakaryocytic differentiation

Physiological Genomics ◽

10.1152/physiolgenomics.00028.2012 ◽

2012 ◽

Vol 44 (12) ◽

pp. 638-650 ◽

Cited By ~ 16

Author(s):

Pani A. Apostolidis ◽

Stephan Lindsey ◽

William M. Miller ◽

Eleftherios T. Papoutsakis

Keyword(s):

Cell Cycle ◽

Dna Synthesis ◽

Cell Line ◽

Target Genes ◽

Control Cell ◽

P53 Expression ◽

Megakaryocytic Differentiation ◽

Knock Down ◽

Cell Cycling ◽

And Control

During endomitosis, megakaryocytes undergo several rounds of DNA synthesis without division leading to polyploidization. In primary megakaryocytes and in the megakaryocytic cell line CHRF, loss or knock-down of p53 enhances cell cycling and inhibits apoptosis, leading to increased polyploidization. To support the hypothesis that p53 suppresses megakaryocytic polyploidization, we show that stable expression of wild-type p53 in K562 cells (a p53-null cell line) attenuates the cells' ability to undergo polyploidization during megakaryocytic differentiation due to diminished DNA synthesis and greater apoptosis. This suggested that p53's effects during megakaryopoiesis are mediated through cell cycle- and apoptosis-related target genes, possibly by arresting DNA synthesis and promoting apoptosis. To identify candidate genes through which p53 mediates these effects, gene expression was compared between p53 knock-down (p53-KD) and control CHRF cells induced to undergo terminal megakaryocytic differentiation using microarray analysis. Among substantially downregulated p53 targets in p53-KD megakaryocytes were cell cycle regulators CDKN1A (p21) and PLK2, proapoptotic FAS, TNFRSF10B, CASP8, NOTCH1, TP53INP1, TP53I3, DRAM1, ZMAT3 and PHLDA3, DNA-damage-related RRM2B and SESN1, and actin component ACTA2, while antiapoptotic CKS1B, BCL2, GTSE1, and p53 family member TP63 were upregulated in p53-KD cells. Additionally, a number of cell cycle-related, proapoptotic, and cytoskeleton-related genes with known functions in megakaryocytes but not known to carry p53-responsive elements were differentially expressed between p53-KD and control CHRF cells. Our data support a model whereby p53 expression during megakaryopoiesis serves to control polyploidization and the transition from endomitosis to apoptosis by impeding cell cycling and promoting apoptosis. Furthermore, we identify a putative p53 regulon that is proposed to orchestrate these effects.

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A Gain of Function Mutation in the NSD2 Histone Methyltransferase Drives Glucocorticoid Resistance Via Blocking Receptor Auto-Induction and BIM/Bmf Expression in ALL

Blood ◽

10.1182/blood-2019-126910 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 3758-3758

Author(s):

Jianping Li ◽

Catalina Troche ◽

Julia Hlavka Zhang ◽

Jonathan Shrimp ◽

Jacob S. Roth ◽

...

Keyword(s):

Cell Cycle ◽

Cell Line ◽

Cell Lines ◽

Mutant Allele ◽

Gene Editing ◽

Conflicts Of Interest ◽

Chemotherapeutic Agents ◽

Rna Seq ◽

Mesenchymal Transition ◽

Pediatric All

Despite improvements in chemotherapy that have increased the 5-year survival rates of pediatric ALL to close to 90%, 15-20% of patients may relapse with a very poor prognosis. Pediatric ALL patients, particularly those in relapse can harbor a specific point mutation (E1099K) in NSD2 (nuclear receptor binding SET domain protein 2) gene, also known as MMSET or WHSC1, which encodes a histone methyl transferase specific for H3K36me2. To understand the biology of mutant NSD2, we used CRISPR-Cas9 gene editing to disrupt the NSD2E1099K mutant allele in B-ALL cell lines (RCH-ACV and SEM) and T-ALL cell line (RPMI-8402) or insert the E1099K mutation into the NSD2WT T-ALL cell line (CEM) and B-ALL cell line (697). Cell lines in which the NSD2E1099K mutant allele is present display increased global levels of H3K36me2 and decreased H3K27me3. NSD2E1099Kcells demonstrate enhanced cell growth, colony formation and migration. NSD2E1099K mutant cell lines assayed by RNA-Seq exhibit an aberrant gene signature, mostly representing gene activation, with activation of signaling pathways, genes implicated in the epithelial mesenchymal transition and prominent expression of neural genes not generally found in hematopoietic tissues. Accordingly, NSD2E1099K cell lines showed prominent tropism to the central neural system in xenografts. To understand why this NSD2 mutations are identified prominently in children who relapse early from therapy for ALL, we performed high-throughput screening in our isogenic cell lines with the National Center for Advancing Translation Science (NCATS) Pharmaceutical Collection and other annotated chemical libraries and found that NSD2E1099K cells are resistant to glucocorticoids (GC) but not to other chemotherapeutic agents used to treat ALL such as vincristine, doxorubicin, cyclophosphamide, methotrexate, and 6-mercaptopurine. Accordingly, patient-derived-xenograft ALL cells with NSD2E1099K mutation were resistant to GC treatment. Reversion of NSD2E1099K mutation to NSD2WT restored GC sensitivity to both B- and T-ALL cell lines, which was accompanied by cell cycle arrest in G1 and induced-apoptosis. Furthermore, knock-in of the NSD2E1099K mutation conferred GC resistance to ALL cell lines by triggering cell cycle progression, proliferation and anti-apoptotic processes. Mice with NSD2E1099K xenografts were completely resistant to GC treatment while treatment of mice injected with isogenic NSD2WT cells led to significant tumor reduction and survival benefit. To illustrate these biological phenotypes and understand the molecular mechanism of GC resistance driven by NSD2E1099Kmutation, we investigated the GC-induced transcriptome, GC receptor (GR) binding sites and related epigenetic changes in isogenic ALL cell lines in response to GC treatment. RNA-Seq showed that GC transcriptional response was almost completely blocked in NSD2E1099K cells, especially in T-ALL cell lines, correlating with their lack of biological response. GC treatment activated apoptotic pathways and downregulated cell cycle and DNA repair pathways only in NSD2WT cells. The critical pro-apoptotic regulators BIM and BMF failed to be activated by GC in NSD2E1099K cells but were prominently activated when the NSD2 mutation was removed. Chromatin immunoprecipitation sequencing (ChIP-Seq) showed that, the NSD2E1099K mutation blocked the ability of GR and CTCF to bind most GC response elements (GREs) such as those within BIM and BMF. While GR binding in NSD2WT cells was accompanied by increased H3K27 acetylation and gene expression, this failed to occur in NSD2 mutant cells. Furthermore, we found that GR RNA and protein levels were repressed in ALL cells expressing NSD2E1099K and GC failed to induce GR expression in these cells. Paradoxically, while H3K27me3 levels were generally decreased in NSD2E1099K cells, we saw increased levels of H3K27me3 at the GRE within the GR gene body where GR itself and CTCF normally bind, suggesting a novel role for the polycomb repressive complex 2 and EZH2 inhibitors for this form of GC resistance. In conclusion, these studies demonstrate that NSD2E1099K mutation may play an important role in treatment failure of pediatric ALL relapse by interfering with the GR expression and its ability to bind and activate key target genes. Gene editing screens are being performed to understand how to overcome this resistance. Disclosures No relevant conflicts of interest to declare.

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TRPV1 promotes opioid analgesia during inflammation

Science Signaling ◽

10.1126/scisignal.aav0711 ◽

2019 ◽

Vol 12 (575) ◽

pp. eaav0711 ◽

Cited By ~ 12

Author(s):

Lilian Basso ◽

Reem Aboushousha ◽

Churmy Yong Fan ◽

Mircea Iftinca ◽

Helvira Melo ◽

...

Keyword(s):

Signaling Pathway ◽

Opioid Receptor ◽

Inflammatory Pain ◽

Transient Receptor Potential ◽

Nuclear Translocation ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Opioid Analgesia ◽

Transient Receptor Potential Vanilloid ◽

Receptor Desensitization

Pain and inflammation are inherently linked responses to injury, infection, or chronic diseases. Given that acute inflammation in humans or mice enhances the analgesic properties of opioids, there is much interest in determining the inflammatory transducers that prime opioid receptor signaling in primary afferent nociceptors. Here, we found that activation of the transient receptor potential vanilloid type 1 (TRPV1) channel stimulated a mitogen-activated protein kinase (MAPK) signaling pathway that was accompanied by the shuttling of the scaffold protein β-arrestin2 to the nucleus. The nuclear translocation of β-arrestin2 in turn prevented its recruitment to the μ-opioid receptor (MOR), the subsequent internalization of agonist-bound MOR, and the suppression of MOR activity that occurs upon receptor desensitization. Using the complete Freund’s adjuvant (CFA) inflammatory pain model to examine the role of TRPV1 in regulating endogenous opioid analgesia in mice, we found that naloxone methiodide (Nal-M), a peripherally restricted, nonselective, and competitive opioid receptor antagonist, slowed the recovery from CFA-induced hypersensitivity in wild-type, but not TRPV1-deficient, mice. Furthermore, we showed that inflammation prolonged morphine-induced antinociception in a mouse model of opioid receptor desensitization, a process that depended on TRPV1. Together, our data reveal a TRPV1-mediated signaling pathway that serves as an endogenous pain-resolution mechanism by promoting the nuclear translocation of β-arrestin2 to minimize MOR desensitization. This previously uncharacterized mechanism may underlie the peripheral opioid control of inflammatory pain. Dysregulation of the TRPV1–β-arrestin2 axis may thus contribute to the transition from acute to chronic pain.

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