{"title":"The PPP2R1A cancer hotspot mutant p.R183W increases clofarabine resistance in uterine serous carcinoma cells by a gain-of-function mechanism.","authors":"Michiel Remmerie, Rüveyda Dok, Zhigang Wang, Judit Domènech Omella, Sophie Alen, Célie Cokelaere, Lisa Lenaerts, Erwin Dreesen, Sandra Nuyts, Rita Derua, Veerle Janssens","doi":"10.1007/s13402-024-00963-5","DOIUrl":null,"url":null,"abstract":"<p><strong>Purpose: </strong>Uterine serous carcinoma (USC) is generally associated with poor prognosis due to a high recurrence rate and frequent treatment resistance; hence, there is a need for improved therapeutic strategies. Molecular analysis of USC identified several molecular markers, useful to improve current treatments or identify new druggable targets. PPP2R1A, encoding the Aα subunit of the tumor suppressive Ser/Thr phosphatase PP2A, is mutated in up to 40% of USCs. Here, we investigated the effect of the p.R183W PPP2R1A hotspot variant on treatment response to the nucleoside analogue clofarabine.</p><p><strong>Methods and results: </strong>USC cells stably expressing p.R183W Aα showed increased resistance to clofarabine treatment in vitro and, corroborated by decreased clofarabine-induced apoptosis, G1 phase arrest, DNA-damage (γH2AX) and activation of ATM and Chk1/2 kinases. Phenotypic rescue by pharmacologic PP2A inhibition or dicer-substrate siRNA (dsiRNA)-mediated B56δ subunit knockdown supported a gain-of-function mechanism of Aα p.R183W, promoting dephosphorylation and inactivation of deoxycytidine kinase (dCK), the cellular enzyme responsible for the conversion of clofarabine into its bioactive form. Therapeutic assessment of related nucleoside analogues (gemcitabine, cladribine) revealed similar effects, but in a cell line-dependent manner. Expression of two other PPP2R1A USC mutants (p.P179R or p.S256F) did not affect clofarabine response in our cell models, arguing for mutant-specific effects on treatment outcome as well.</p><p><strong>Conclusions: </strong>While our results call for PPP2R1A mutant and context-dependent effects upon clofarabine/nucleoside analogue monotherapy, combining clofarabine with a pharmacologic PP2A inhibitor proved synergistically in all tested conditions, highlighting a new generally applicable strategy to improve treatment outcome in USC.</p>","PeriodicalId":9690,"journal":{"name":"Cellular Oncology","volume":null,"pages":null},"PeriodicalIF":6.6000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cellular Oncology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s13402-024-00963-5","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/6/18 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"Medicine","Score":null,"Total":0}
引用次数: 0
Abstract
Purpose: Uterine serous carcinoma (USC) is generally associated with poor prognosis due to a high recurrence rate and frequent treatment resistance; hence, there is a need for improved therapeutic strategies. Molecular analysis of USC identified several molecular markers, useful to improve current treatments or identify new druggable targets. PPP2R1A, encoding the Aα subunit of the tumor suppressive Ser/Thr phosphatase PP2A, is mutated in up to 40% of USCs. Here, we investigated the effect of the p.R183W PPP2R1A hotspot variant on treatment response to the nucleoside analogue clofarabine.
Methods and results: USC cells stably expressing p.R183W Aα showed increased resistance to clofarabine treatment in vitro and, corroborated by decreased clofarabine-induced apoptosis, G1 phase arrest, DNA-damage (γH2AX) and activation of ATM and Chk1/2 kinases. Phenotypic rescue by pharmacologic PP2A inhibition or dicer-substrate siRNA (dsiRNA)-mediated B56δ subunit knockdown supported a gain-of-function mechanism of Aα p.R183W, promoting dephosphorylation and inactivation of deoxycytidine kinase (dCK), the cellular enzyme responsible for the conversion of clofarabine into its bioactive form. Therapeutic assessment of related nucleoside analogues (gemcitabine, cladribine) revealed similar effects, but in a cell line-dependent manner. Expression of two other PPP2R1A USC mutants (p.P179R or p.S256F) did not affect clofarabine response in our cell models, arguing for mutant-specific effects on treatment outcome as well.
Conclusions: While our results call for PPP2R1A mutant and context-dependent effects upon clofarabine/nucleoside analogue monotherapy, combining clofarabine with a pharmacologic PP2A inhibitor proved synergistically in all tested conditions, highlighting a new generally applicable strategy to improve treatment outcome in USC.
Cellular OncologyBiochemistry, Genetics and Molecular Biology-Cancer Research
CiteScore
10.40
自引率
1.50%
发文量
0
审稿时长
16 weeks
期刊介绍:
The Official Journal of the International Society for Cellular Oncology
Focuses on translational research
Addresses the conversion of cell biology to clinical applications
Cellular Oncology publishes scientific contributions from various biomedical and clinical disciplines involved in basic and translational cancer research on the cell and tissue level, technical and bioinformatics developments in this area, and clinical applications. This includes a variety of fields like genome technology, micro-arrays and other high-throughput techniques, genomic instability, SNP, DNA methylation, signaling pathways, DNA organization, (sub)microscopic imaging, proteomics, bioinformatics, functional effects of genomics, drug design and development, molecular diagnostics and targeted cancer therapies, genotype-phenotype interactions.
A major goal is to translate the latest developments in these fields from the research laboratory into routine patient management. To this end Cellular Oncology forms a platform of scientific information exchange between molecular biologists and geneticists, technical developers, pathologists, (medical) oncologists and other clinicians involved in the management of cancer patients.
In vitro studies are preferentially supported by validations in tumor tissue with clinicopathological associations.