PMID- 38374003 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20240222 IS - 2162-3619 (Print) IS - 2162-3619 (Electronic) IS - 2162-3619 (Linking) VI - 13 IP - 1 DP - 2024 Feb 19 TI - Blockade of the lncRNA-DOT1L-LAMP5 axis enhances autophagy and promotes degradation of MLL fusion proteins. PG - 18 LID - 10.1186/s40164-024-00488-5 [doi] LID - 18 AB - 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. CI - (c) 2024. The Author(s). FAU - Chen, Tian-Qi AU - Chen TQ AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Huang, Heng-Jing AU - Huang HJ AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Zhu, Shun-Xin AU - Zhu SX AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Chen, Xiao-Tong AU - Chen XT AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Pu, Ke-Jia AU - Pu KJ AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Wang, Dan AU - Wang D AD - State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangdong, Guangzhou, 510060, China. FAU - An, Yan AU - An Y AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Lian, Jun-Yi AU - Lian JY AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Sun, Yu-Meng AU - Sun YM AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. FAU - Chen, Yue-Qin AU - Chen YQ AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. lsscyq@mail.sysu.edu.cn. AD - School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, P. R. China. lsscyq@mail.sysu.edu.cn. FAU - Wang, Wen-Tao AU - Wang WT AD - MOE Key Laboratory of Gene Function and Regulation, Guangdong Province Key Laboratory of Pharmaceutical Functional Genes, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China. wangwt8@mail.sysu.edu.cn. AD - School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, P. R. China. wangwt8@mail.sysu.edu.cn. LA - eng GR - 32270598/National Natural Science Foundation of China/ GR - 32370594/National Natural Science Foundation of China/ GR - 2022YFA1300020/National Key Research and Development Program of China/ GR - 2021YFA1300502/National Key Research and Development Program of China/ GR - 2021B1515020002/Natural Science Foundation of Guangdong Province/ PT - Journal Article DEP - 20240219 PL - England TA - Exp Hematol Oncol JT - Experimental hematology & oncology JID - 101590676 PMC - PMC10877858 OTO - NOTNLM OT - Autophagy OT - DOT1L OT - LAMP5 OT - LAMP5-AS1 OT - MLL leukemia OT - lncRNA COIS- The authors declare no competing interests. EDAT- 2024/02/20 11:50 MHDA- 2024/02/20 11:51 PMCR- 2024/02/19 CRDT- 2024/02/19 23:38 PHST- 2024/01/05 00:00 [received] PHST- 2024/02/12 00:00 [accepted] PHST- 2024/02/20 11:51 [medline] PHST- 2024/02/20 11:50 [pubmed] PHST- 2024/02/19 23:38 [entrez] PHST- 2024/02/19 00:00 [pmc-release] AID - 10.1186/s40164-024-00488-5 [pii] AID - 488 [pii] AID - 10.1186/s40164-024-00488-5 [doi] PST - epublish SO - Exp Hematol Oncol. 2024 Feb 19;13(1):18. doi: 10.1186/s40164-024-00488-5.