MYCN and PRC1 cooperatively repress docosahexaenoic acid synthesis in neuroblastoma via ELOVL2

Abstract Background The MYCN amplification is a defining hallmark of high-risk neuroblastoma. Due to irregular oncogenes orchestration, tumor cells exhibit distinct fatty acid metabolic features from non-tumor cells. However, the function of MYCN in neuroblastoma fatty acid metabolism reprogramming remains unknown. Methods Gas Chromatography-Mass Spectrometer (GC-MS) was used to find the potential target fatty acid metabolites of MYCN. Real-time PCR (RT-PCR) and clinical bioinformatics analysis was used to find the related target genes. The function of the identified target gene ELOVL2 on cell growth was detected through CCK-8 assay, Soft agar colony formation assay, flow Cytometry assay and mouse xenograft. Chromatin immunoprecipitation (ChIP) and Immunoprecipitation-Mass Spectrometer (IP-MS) further identified the target gene and the co-repressor of MYCN. Results The fatty acid profile of MYCN-depleted neuroblastoma cells identified docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid with anti-tumor activity, significantly increased after MYCN depletion. Compared with MYCN single-copy neuroblastoma cells, DHA level was significantly lower in MYCN-amplified neuroblastoma cells. RT-PCR and clinical bioinformatics analysis discovered that MYCN interfered DHA accumulation via ELOVL fatty acid elongase 2 (ELOVL2) which is a rate-limiting enzyme of cellular DHA synthesis. Enforced ELOVL2 expression in MYCN-amplified neuroblastoma cells led to decreased cell growth and counteracted the growth-promoting effect of MYCN overexpression both in vitro and vivo. ELOVL2 Knockdown showed the opposite effect in MYCN single-copy neuroblastoma cells. In primary neuroblastoma, high ELOVL2 transcription correlated with favorable clinical tumor biology and patient survival. The mechanism of MYCN-mediated ELOVL2 inhibition contributed to epigenetic regulation. MYCN recruited PRC1 (Polycomb repressive complex 1), catalysed H2AK119ub (histone 2A lysine 119 monoubiquitination) and inhibited subsequent ELOVL2 transcription. Conclusions The tumor suppressive properties of DHA and ELOVL2 are repressed by the MYCN and PRC1 jointly, which suggests a new epigenetic mechanism of MYCN-mediated fatty acid regulation and indicates PRC1 inhibition as a potential novel strategy to activate ELOVL2 suppressive functions.

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Disseminated tumor cells in bone marrow of breast cancer patients–Comparison of immunocytochemistry and RT-PCR

Geburtshilfe und Frauenheilkunde ◽

10.1055/s-2006-952799 ◽

2006 ◽

Vol 66 (S 01) ◽

Author(s):

T Fehm ◽

S Becker ◽

MJ Banys ◽

G Becker-Pergola ◽

S Duerr-Stoerzer ◽

...

Keyword(s):

Breast Cancer ◽

Bone Marrow ◽

Cancer Patients ◽

Tumor Cells ◽

Disseminated Tumor Cells ◽

Breast Cancer Patients ◽

Rt Pcr

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EphA2 super-enhancer promotes tumor progression by recruiting FOSL2 and TCF7L2 to activate the target gene EphA2

Cell Death and Disease ◽

10.1038/s41419-021-03538-6 ◽

2021 ◽

Vol 12 (3) ◽

Author(s):

Shuang Cui ◽

Qiong Wu ◽

Ming Liu ◽

Mu Su ◽

ShiYou Liu ◽

...

Keyword(s):

Tumor Progression ◽

Tumor Cells ◽

Target Gene ◽

Super Enhancer ◽

Proliferation And Metastasis ◽

Active Transcription ◽

Hct 116 ◽

Large Clusters

AbstractSuper-enhancers or stretch enhancers (SEs) consist of large clusters of active transcription enhancers which promote the expression of critical genes that define cell identity during development and disease. However, the role of many super-enhancers in tumor cells remains unclear. This study aims to explore the function and mechanism of a new super-enhancer in various tumor cells. A new super-enhancer that exists in a variety of tumors named EphA2-Super-enhancer (EphA2-SE) was found using multiple databases and further identified. CRISPR/Cas9-mediated deletion of EphA2-SE results in the significant downregulation of its target gene EphA2. Mechanistically, we revealed that the core active region of EphA2-SE comprises E1 component enhancer, which recruits TCF7L2 and FOSL2 transcription factors to drive the expression of EphA2, induce cell proliferation and metastasis. Bioinformatics analysis of RNA-seq data and functional experiments in vitro illustrated that EphA2-SE deletion inhibited cell growth and metastasis by blocking PI3K/AKT and Wnt/β-catenin pathway in HeLa, HCT-116 and MCF-7 cells. Overexpression of EphA2 in EphA2-SE−/− clones rescued the effect of EphA2-SE deletion on proliferation and metastasis. Subsequent xenograft animal model revealed that EphA2-SE deletion suppressed tumor proliferation and survival in vivo. Taken together, these findings demonstrate that EphA2-SE plays an oncogenic role and promotes tumor progression in various tumors by recruiting FOSL2 and TCF7L2 to drive the expression of oncogene EphA2.

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Identification and Validation of New Cancer Stem Cell-Related Genes and Their Regulatory microRNAs in Colorectal Cancerogenesis

Biomedicines ◽

10.3390/biomedicines9020179 ◽

2021 ◽

Vol 9 (2) ◽

pp. 179

Author(s):

Kristian Urh ◽

Margareta Žlajpah ◽

Nina Zidar ◽

Emanuela Boštjančič

Keyword(s):

Experimental Validation ◽

Target Gene ◽

Bioinformatics Analysis ◽

Early Carcinoma ◽

Significant Progress ◽

Formalin Fixed Paraffin ◽

Formalin Fixed Paraffin Embedded ◽

Node Metastases ◽

Formalin Fixed ◽

Made In

Significant progress has been made in the last decade in our understanding of the pathogenetic mechanisms of colorectal cancer (CRC). Cancer stem cells (CSC) have gained much attention and are now believed to play a crucial role in the pathogenesis of various cancers, including CRC. In the current study, we validated gene expression of four genes related to CSC, L1TD1, SLITRK6, ST6GALNAC1 and TCEA3, identified in a previous bioinformatics analysis. Using bioinformatics, potential miRNA-target gene correlations were prioritized. In total, 70 formalin-fixed paraffin-embedded biopsy samples from 47 patients with adenoma, adenoma with early carcinoma and CRC without and with lymph node metastases were included. The expression of selected genes and microRNAs (miRNAs) was evaluated using quantitative PCR. Differential expression of all investigated genes and four of six prioritized miRNAs (hsa-miR-199a-3p, hsa-miR-335-5p, hsa-miR-425-5p, hsa-miR-1225-3p, hsa-miR-1233-3p and hsa-miR-1303) was found in at least one group of CRC cancerogenesis. L1TD1, SLITRK6, miR-1233-3p and miR-1225-3p were correlated to the level of malignancy. A negative correlation between miR-199a-3p and its predicted target SLITRK6 was observed, showing potential for further experimental validation in CRC. Our results provide further evidence that CSC-related genes and their regulatory miRNAs are involved in CRC development and progression and suggest that some them, particularly miR-199a-3p and its SLITRK6 target gene, are promising for further validation in CRC.

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Recycling of docosahexaenoic acid in rat retinas during n-3 fatty acid deficiency.

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)41904-2 ◽

1991 ◽

Vol 32 (12) ◽

pp. 2009-2017

Author(s):

AM Stinson ◽

RD Wiegand ◽

RE Anderson

Keyword(s):

Fatty Acid ◽

Docosahexaenoic Acid ◽

Acid Deficiency ◽

Fatty Acid Deficiency

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UBE4B, a microRNA-9 target gene, promotes autophagy-mediated Tau degradation

Nature Communications ◽

10.1038/s41467-021-23597-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Manivannan Subramanian ◽

Seung Jae Hyeon ◽

Tanuza Das ◽

Yoon Seok Suh ◽

Yun Kyung Kim ◽

...

Keyword(s):

Mouse Model ◽

Ubiquitin Ligase ◽

Therapeutic Approach ◽

Target Gene ◽

Neuroblastoma Cells ◽

E3 Ligase ◽

Tau Hyperphosphorylation ◽

Phosphorylated Tau ◽

Major Pathway ◽

The Brain

AbstractThe formation of hyperphosphorylated intracellular Tau tangles in the brain is a hallmark of Alzheimer’s disease (AD). Tau hyperphosphorylation destabilizes microtubules, promoting neurodegeneration in AD patients. To identify suppressors of tau-mediated AD, we perform a screen using a microRNA (miR) library in Drosophila and identify the miR-9 family as suppressors of human tau overexpression phenotypes. CG11070, a miR-9a target gene, and its mammalian orthologue UBE4B, an E3/E4 ubiquitin ligase, alleviate eye neurodegeneration, synaptic bouton defects, and crawling phenotypes in Drosophila human tau overexpression models. Total and phosphorylated Tau levels also decrease upon CG11070 or UBE4B overexpression. In mammalian neuroblastoma cells, overexpression of UBE4B and STUB1, which encodes the E3 ligase CHIP, increases the ubiquitination and degradation of Tau. In the Tau-BiFC mouse model, UBE4B and STUB1 overexpression also increase oligomeric Tau degradation. Inhibitor assays of the autophagy and proteasome systems reveal that the autophagy-lysosome system is the major pathway for Tau degradation in this context. These results demonstrate that UBE4B, a miR-9 target gene, promotes autophagy-mediated Tau degradation together with STUB1, and is thus an innovative therapeutic approach for AD.

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