{"title":"3013 – LEDGF/P75 PLAYS OPPOSING ROLES IN CHEMORESISTANCE IN DIFFERENT LEUKEMIAS","authors":"","doi":"10.1016/j.exphem.2024.104335","DOIUrl":null,"url":null,"abstract":"<div><p>Lens Epithelium Derived Growth Factor/p75 (LEDGF/p75) is a chromatin-associated protein involved in multiple malignancies. It tethers the MLL/KMT2A fusion protein to the chromatin and plays a critical role in the initiation and maintenance of MLL-r leukemia which mostly affects pediatric patients and is linked to a high rate of relapse and resistance to conventional chemotherapy. Moreover, LEDGF/p75 is overexpressed in AML and prostate cancer patients who are resistant to chemotherapy. We have previously shown that reduced LEDGF/p75 expression sensitizes proliferation and survival of KMT2A-r Thp1 cells to cytarabine treatment through the sphingosine-1 pathway. Here, we studied modulation of chemoresistance by LEDGF/p75 in various types of leukemia. At first, we corroborated the results in Thp1 and expanded these findings by ectopically expressing LEDGF/p75 in the KMT2A-r Molm13 cells that naturally express low levels of LEDGF/p75. Overexpression of LEDGF/p75 in those cells resulted in increased proliferation and reduced apoptosis in the presence of cytarabine. A similar result was obtained after LEDGF/p75 depletion in K562 (CML, KMT2A WT) since a 3-fold increase in sensitivity to vincristine compared to the control was found. Vincristine treated K562 LEDGF/p75 KD cells show more apoptosis and increased caspase3 expression. Interestingly, LEDGF/p75 depletion in SEM cells (ALL, KMT2A-r) resulted in 4-fold more proliferation and less apoptosis upon cytarabine treatment compared to cells expressing mock miRNA. In conclusion, LEDGF/p75 induces chemoresistance in Thp1 and K562 cells to cytarabine and vincristine respectively but sensitizes SEM cells to cytarabine. Our findings highlight the opposing role of LEDGF/p75 in modulating chemoresistance across leukemias. Targeting LEDGF/p75 may be a promising strategy to enhance chemotherapy efficacy in specific leukemic subtypes.</p></div>","PeriodicalId":12202,"journal":{"name":"Experimental hematology","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0301472X24001942/pdfft?md5=674e3a4f84c1489bf5269314c4ad6283&pid=1-s2.0-S0301472X24001942-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Experimental hematology","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0301472X24001942","RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"HEMATOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Lens Epithelium Derived Growth Factor/p75 (LEDGF/p75) is a chromatin-associated protein involved in multiple malignancies. It tethers the MLL/KMT2A fusion protein to the chromatin and plays a critical role in the initiation and maintenance of MLL-r leukemia which mostly affects pediatric patients and is linked to a high rate of relapse and resistance to conventional chemotherapy. Moreover, LEDGF/p75 is overexpressed in AML and prostate cancer patients who are resistant to chemotherapy. We have previously shown that reduced LEDGF/p75 expression sensitizes proliferation and survival of KMT2A-r Thp1 cells to cytarabine treatment through the sphingosine-1 pathway. Here, we studied modulation of chemoresistance by LEDGF/p75 in various types of leukemia. At first, we corroborated the results in Thp1 and expanded these findings by ectopically expressing LEDGF/p75 in the KMT2A-r Molm13 cells that naturally express low levels of LEDGF/p75. Overexpression of LEDGF/p75 in those cells resulted in increased proliferation and reduced apoptosis in the presence of cytarabine. A similar result was obtained after LEDGF/p75 depletion in K562 (CML, KMT2A WT) since a 3-fold increase in sensitivity to vincristine compared to the control was found. Vincristine treated K562 LEDGF/p75 KD cells show more apoptosis and increased caspase3 expression. Interestingly, LEDGF/p75 depletion in SEM cells (ALL, KMT2A-r) resulted in 4-fold more proliferation and less apoptosis upon cytarabine treatment compared to cells expressing mock miRNA. In conclusion, LEDGF/p75 induces chemoresistance in Thp1 and K562 cells to cytarabine and vincristine respectively but sensitizes SEM cells to cytarabine. Our findings highlight the opposing role of LEDGF/p75 in modulating chemoresistance across leukemias. Targeting LEDGF/p75 may be a promising strategy to enhance chemotherapy efficacy in specific leukemic subtypes.
期刊介绍:
Experimental Hematology publishes new findings, methodologies, reviews and perspectives in all areas of hematology and immune cell formation on a monthly basis that may include Special Issues on particular topics of current interest. The overall goal is to report new insights into how normal blood cells are produced, how their production is normally regulated, mechanisms that contribute to hematological diseases and new approaches to their treatment. Specific topics may include relevant developmental and aging processes, stem cell biology, analyses of intrinsic and extrinsic regulatory mechanisms, in vitro behavior of primary cells, clonal tracking, molecular and omics analyses, metabolism, epigenetics, bioengineering approaches, studies in model organisms, novel clinical observations, transplantation biology and new therapeutic avenues.