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TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas

BACKGROUND: Xp11.2 translocation renal cell carcinoma (tRCC) is mainly caused by translocation of the TFE3 gene located on chromosome Xp11.2 and is characterized by overexpression of the TFE3 fusion gene. Patients are diagnosed with tRCC usually before 45 years of age with poor prognosis. We investi...

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Autores principales: Yin, Xiaoqin, Wang, Bo, Gan, Weidong, Zhuang, Wenyuan, Xiang, Zou, Han, Xiaodong, Li, Dongmei
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6408813/
https://www.ncbi.nlm.nih.gov/pubmed/30849994
http://dx.doi.org/10.1186/s13046-019-1101-7
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author Yin, Xiaoqin
Wang, Bo
Gan, Weidong
Zhuang, Wenyuan
Xiang, Zou
Han, Xiaodong
Li, Dongmei
author_facet Yin, Xiaoqin
Wang, Bo
Gan, Weidong
Zhuang, Wenyuan
Xiang, Zou
Han, Xiaodong
Li, Dongmei
author_sort Yin, Xiaoqin
collection PubMed
description BACKGROUND: Xp11.2 translocation renal cell carcinoma (tRCC) is mainly caused by translocation of the TFE3 gene located on chromosome Xp11.2 and is characterized by overexpression of the TFE3 fusion gene. Patients are diagnosed with tRCC usually before 45 years of age with poor prognosis. We investigated this disease using two tRCC cell lines, UOK109 and UOK120, in this study. METHODS: The purpose of this study was to investigate the pathogenic mechanism of TFE3 fusions in tRCC based on its subcellular localization, nuclear translocation and transcriptional activity. The expression of TFE3 fusions and other related genes were analyzed by quantitative reverse transcription PCR (qRT-PCR) and Western blot. The subcellular localization of TFE3 was determined using immunofluorescence. The transcriptional activity of TFE3 fusions was measured using a luciferase reporter assay and ChIP analysis. In some experiments, TFE3 fusions were depleted by RNAi or gene knockdown. The TFE3 fusion segments were cloned into a plasmid expression system for expression in cells. RESULTS: Our results demonstrated that TFE3 fusions were overexpressed in tRCC with a strong nuclear retention irrespective of treatment with an mTORC1 inhibitor or not. TFE3 fusions lost its co-localization with lysosomal proteins and decreased its interaction with the chaperone 14–3-3 proteins in UOK109 and UOK120 cells. However, the fusion segments of TFE3 could not translocate to the nucleus and inhibition of Gsk3β could increase the cytoplasmic retention of TFE3 fusions. Both the luciferase reporter assay and ChIP analysis demonstrated that TFE3 fusions could bind to the promoters of the target genes as a wild-type TFE3 protein. Knockdown of TFE3 results in decreased expression of those genes responsible for lysosomal biogenesis and other target genes. The ChIP-seq data further verified that, in addition to lysosomal genes, TFE3 fusions could regulate genes involved in cellular responses to hypoxic stress and transcription. CONCLUSIONS: Our results indicated that the overexpressed TFE3 fusions were capable of escaping from the control by the mTOR signaling pathway and were accumulated in the nucleus in UOK109 and UOK120 cells. The nuclear retention of TFE3 fusions promoted the expression of lysosomal genes and other target genes, facilitating cancer cell resistance against an extreme environment. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13046-019-1101-7) contains supplementary material, which is available to authorized users.
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spelling pubmed-64088132019-03-21 TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas Yin, Xiaoqin Wang, Bo Gan, Weidong Zhuang, Wenyuan Xiang, Zou Han, Xiaodong Li, Dongmei J Exp Clin Cancer Res Research BACKGROUND: Xp11.2 translocation renal cell carcinoma (tRCC) is mainly caused by translocation of the TFE3 gene located on chromosome Xp11.2 and is characterized by overexpression of the TFE3 fusion gene. Patients are diagnosed with tRCC usually before 45 years of age with poor prognosis. We investigated this disease using two tRCC cell lines, UOK109 and UOK120, in this study. METHODS: The purpose of this study was to investigate the pathogenic mechanism of TFE3 fusions in tRCC based on its subcellular localization, nuclear translocation and transcriptional activity. The expression of TFE3 fusions and other related genes were analyzed by quantitative reverse transcription PCR (qRT-PCR) and Western blot. The subcellular localization of TFE3 was determined using immunofluorescence. The transcriptional activity of TFE3 fusions was measured using a luciferase reporter assay and ChIP analysis. In some experiments, TFE3 fusions were depleted by RNAi or gene knockdown. The TFE3 fusion segments were cloned into a plasmid expression system for expression in cells. RESULTS: Our results demonstrated that TFE3 fusions were overexpressed in tRCC with a strong nuclear retention irrespective of treatment with an mTORC1 inhibitor or not. TFE3 fusions lost its co-localization with lysosomal proteins and decreased its interaction with the chaperone 14–3-3 proteins in UOK109 and UOK120 cells. However, the fusion segments of TFE3 could not translocate to the nucleus and inhibition of Gsk3β could increase the cytoplasmic retention of TFE3 fusions. Both the luciferase reporter assay and ChIP analysis demonstrated that TFE3 fusions could bind to the promoters of the target genes as a wild-type TFE3 protein. Knockdown of TFE3 results in decreased expression of those genes responsible for lysosomal biogenesis and other target genes. The ChIP-seq data further verified that, in addition to lysosomal genes, TFE3 fusions could regulate genes involved in cellular responses to hypoxic stress and transcription. CONCLUSIONS: Our results indicated that the overexpressed TFE3 fusions were capable of escaping from the control by the mTOR signaling pathway and were accumulated in the nucleus in UOK109 and UOK120 cells. The nuclear retention of TFE3 fusions promoted the expression of lysosomal genes and other target genes, facilitating cancer cell resistance against an extreme environment. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13046-019-1101-7) contains supplementary material, which is available to authorized users. BioMed Central 2019-03-08 /pmc/articles/PMC6408813/ /pubmed/30849994 http://dx.doi.org/10.1186/s13046-019-1101-7 Text en © The Author(s). 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Yin, Xiaoqin
Wang, Bo
Gan, Weidong
Zhuang, Wenyuan
Xiang, Zou
Han, Xiaodong
Li, Dongmei
TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas
title TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas
title_full TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas
title_fullStr TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas
title_full_unstemmed TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas
title_short TFE3 fusions escape from controlling of mTOR signaling pathway and accumulate in the nucleus promoting genes expression in Xp11.2 translocation renal cell carcinomas
title_sort tfe3 fusions escape from controlling of mtor signaling pathway and accumulate in the nucleus promoting genes expression in xp11.2 translocation renal cell carcinomas
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6408813/
https://www.ncbi.nlm.nih.gov/pubmed/30849994
http://dx.doi.org/10.1186/s13046-019-1101-7
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