Tian-Qi Chen, Heng-Jing Huang, Shun-Xin Zhu, Xiao-Tong Chen, Ke-Jia Pu, Dan Wang, Yan An, Jun-Yi Lian, Yu-Meng Sun, Yue-Qin Chen, Wen-Tao Wang
{"title":"阻断lncRNA-DOT1L-LAMP5轴可增强自噬作用并促进MLL融合蛋白的降解。","authors":"Tian-Qi Chen, Heng-Jing Huang, Shun-Xin Zhu, Xiao-Tong Chen, Ke-Jia Pu, Dan Wang, Yan An, Jun-Yi Lian, Yu-Meng Sun, Yue-Qin Chen, Wen-Tao Wang","doi":"10.1186/s40164-024-00488-5","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Mixed-lineage leukemia (MLL) fusion gene caused by chromosomal rearrangement is a dominant oncogenic driver in leukemia. Due to having diverse MLL rearrangements and complex characteristics, MLL leukemia treated by currently available strategies is frequently associated with a poor outcome. Therefore, there is an urgent need to identify novel therapeutic targets for hematological malignancies with MLL rearrangements.</p><p><strong>Methods: </strong>qRT-PCR, western blot, and spearman correction analysis were used to validate the regulation of LAMP5-AS1 on LAMP5 expression. In vitro and in vivo experiments were conducted to assess the functional relevance of LAMP5-AS1 in MLL leukemia cell survival. We utilized chromatin isolation by RNA purification (ChIRP) assay, RNA pull-down assay, chromatin immunoprecipitation (ChIP), RNA fluorescence in situ hybridization (FISH), and immunofluorescence to elucidate the relationship among LAMP5-AS1, DOT1L, and the LAMP5 locus. Autophagy regulation by LAMP5-AS1 was evaluated through LC3B puncta, autolysosome observation via transmission electron microscopy (TEM), and mRFP-GFP-LC3 puncta in autophagic flux.</p><p><strong>Results: </strong>The study shows the crucial role of LAMP5-AS1 in promoting MLL leukemia cell survival. LAMP5-AS1 acts as a novel autophagic suppressor, safeguarding MLL fusion proteins from autophagic degradation. Knocking down LAMP5-AS1 significantly induced apoptosis in MLL leukemia cell lines and primary cells and extended the survival of mice in vivo. Mechanistically, LAMP5-AS1 recruits the H3K79 histone methyltransferase DOT1L to LAMP5 locus, directly activating LAMP5 expression. Importantly, blockade of LAMP5-AS1-LAMP5 axis can represses MLL fusion proteins by enhancing their degradation.</p><p><strong>Conclusions: </strong>The findings underscore the significance of LAMP5-AS1 in MLL leukemia progression through the regulation of the autophagy pathway. Additionally, this study unveils the novel lncRNA-DOT1L-LAMP5 axis as promising therapeutic targets for degrading MLL fusion proteins.</p>","PeriodicalId":12180,"journal":{"name":"Experimental Hematology & Oncology","volume":null,"pages":null},"PeriodicalIF":9.4000,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10877858/pdf/","citationCount":"0","resultStr":"{\"title\":\"Blockade of the lncRNA-DOT1L-LAMP5 axis enhances autophagy and promotes degradation of MLL fusion proteins.\",\"authors\":\"Tian-Qi Chen, Heng-Jing Huang, Shun-Xin Zhu, Xiao-Tong Chen, Ke-Jia Pu, Dan Wang, Yan An, Jun-Yi Lian, Yu-Meng Sun, Yue-Qin Chen, Wen-Tao Wang\",\"doi\":\"10.1186/s40164-024-00488-5\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Background: </strong>Mixed-lineage leukemia (MLL) fusion gene caused by chromosomal rearrangement is a dominant oncogenic driver in leukemia. Due to having diverse MLL rearrangements and complex characteristics, MLL leukemia treated by currently available strategies is frequently associated with a poor outcome. Therefore, there is an urgent need to identify novel therapeutic targets for hematological malignancies with MLL rearrangements.</p><p><strong>Methods: </strong>qRT-PCR, western blot, and spearman correction analysis were used to validate the regulation of LAMP5-AS1 on LAMP5 expression. In vitro and in vivo experiments were conducted to assess the functional relevance of LAMP5-AS1 in MLL leukemia cell survival. We utilized chromatin isolation by RNA purification (ChIRP) assay, RNA pull-down assay, chromatin immunoprecipitation (ChIP), RNA fluorescence in situ hybridization (FISH), and immunofluorescence to elucidate the relationship among LAMP5-AS1, DOT1L, and the LAMP5 locus. Autophagy regulation by LAMP5-AS1 was evaluated through LC3B puncta, autolysosome observation via transmission electron microscopy (TEM), and mRFP-GFP-LC3 puncta in autophagic flux.</p><p><strong>Results: </strong>The study shows the crucial role of LAMP5-AS1 in promoting MLL leukemia cell survival. LAMP5-AS1 acts as a novel autophagic suppressor, safeguarding MLL fusion proteins from autophagic degradation. Knocking down LAMP5-AS1 significantly induced apoptosis in MLL leukemia cell lines and primary cells and extended the survival of mice in vivo. Mechanistically, LAMP5-AS1 recruits the H3K79 histone methyltransferase DOT1L to LAMP5 locus, directly activating LAMP5 expression. Importantly, blockade of LAMP5-AS1-LAMP5 axis can represses MLL fusion proteins by enhancing their degradation.</p><p><strong>Conclusions: </strong>The findings underscore the significance of LAMP5-AS1 in MLL leukemia progression through the regulation of the autophagy pathway. Additionally, this study unveils the novel lncRNA-DOT1L-LAMP5 axis as promising therapeutic targets for degrading MLL fusion proteins.</p>\",\"PeriodicalId\":12180,\"journal\":{\"name\":\"Experimental Hematology & Oncology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":9.4000,\"publicationDate\":\"2024-02-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10877858/pdf/\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Experimental Hematology & Oncology\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1186/s40164-024-00488-5\",\"RegionNum\":1,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"HEMATOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Experimental Hematology & Oncology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1186/s40164-024-00488-5","RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"HEMATOLOGY","Score":null,"Total":0}
Blockade of the lncRNA-DOT1L-LAMP5 axis enhances autophagy and promotes degradation of MLL fusion proteins.
Background: Mixed-lineage leukemia (MLL) fusion gene caused by chromosomal rearrangement is a dominant oncogenic driver in leukemia. Due to having diverse MLL rearrangements and complex characteristics, MLL leukemia treated by currently available strategies is frequently associated with a poor outcome. Therefore, there is an urgent need to identify novel therapeutic targets for hematological malignancies with MLL rearrangements.
Methods: qRT-PCR, western blot, and spearman correction analysis were used to validate the regulation of LAMP5-AS1 on LAMP5 expression. In vitro and in vivo experiments were conducted to assess the functional relevance of LAMP5-AS1 in MLL leukemia cell survival. We utilized chromatin isolation by RNA purification (ChIRP) assay, RNA pull-down assay, chromatin immunoprecipitation (ChIP), RNA fluorescence in situ hybridization (FISH), and immunofluorescence to elucidate the relationship among LAMP5-AS1, DOT1L, and the LAMP5 locus. Autophagy regulation by LAMP5-AS1 was evaluated through LC3B puncta, autolysosome observation via transmission electron microscopy (TEM), and mRFP-GFP-LC3 puncta in autophagic flux.
Results: The study shows the crucial role of LAMP5-AS1 in promoting MLL leukemia cell survival. LAMP5-AS1 acts as a novel autophagic suppressor, safeguarding MLL fusion proteins from autophagic degradation. Knocking down LAMP5-AS1 significantly induced apoptosis in MLL leukemia cell lines and primary cells and extended the survival of mice in vivo. Mechanistically, LAMP5-AS1 recruits the H3K79 histone methyltransferase DOT1L to LAMP5 locus, directly activating LAMP5 expression. Importantly, blockade of LAMP5-AS1-LAMP5 axis can represses MLL fusion proteins by enhancing their degradation.
Conclusions: The findings underscore the significance of LAMP5-AS1 in MLL leukemia progression through the regulation of the autophagy pathway. Additionally, this study unveils the novel lncRNA-DOT1L-LAMP5 axis as promising therapeutic targets for degrading MLL fusion proteins.
期刊介绍：
Experimental Hematology & Oncology is an open access journal that encompasses all aspects of hematology and oncology with an emphasis on preclinical, basic, patient-oriented and translational research. The journal acts as an international platform for sharing laboratory findings in these areas and makes a deliberate effort to publish clinical trials with 'negative' results and basic science studies with provocative findings.
Experimental Hematology & Oncology publishes original work, hypothesis, commentaries and timely reviews. With open access and rapid turnaround time from submission to publication, the journal strives to be a hub for disseminating new knowledge and discussing controversial topics for both basic scientists and busy clinicians in the closely related fields of hematology and oncology.
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