RT Journal Article
SR Electronic
T1 Genome-wide silencing screen in mesothelioma cells reveals that loss of function of BAP1 induces chemoresistance to ribonucleotide reductase inhibition: implication for therapy
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 381533
DO 10.1101/381533
A1 Agata Okonska
A1 Saskja Bühler
A1 Vasundhara Rao
A1 Manuel Ronner
A1 Maxime Blijlevens
A1 Ida Van der Meulen-Muileman
A1 Renee de Menezes
A1 Egbert Smit
A1 Walter Weder
A1 Rolf Stahel
A1 Lorenza Penengo
A1 Victor van Beusechem
A1 Emanuela Felley-Bosco
YR 2018
UL http://biorxiv.org/content/early/2018/07/31/381533.abstract
AB Introduction Loss of function of BRCA1 associated protein 1 (BAP1) is observed in about 50% of malignant pleural mesothelioma (MPM) cases. The aim of this study was to investigate whether this aspect could be exploited for targeted therapy.Methods A genetically engineered model was established expressing either functional or nonfunctional BAP1 and whole-genome siRNA screens were performed assessing impaired survival between the two cell lines. Cytotoxity induced by gemcitabine and hydroxyurea were assessed in a panel of BAP1-WT and BAP1-mut/del cell lines. Functional studies were carried out in BAP1 mut/del cell line reconstituted with BAP1 WT or BAP1 C91A (catalytically dead mutant) and in BAP1 WT cell line upon siRNA-mediated knock-down of BAP1.Results The whole-genome siRNA screen unexpectedly revealed 11 hits (FDR<0.05) more cytotoxic for BAP1-proficient cells. Two actionable targets, RRM1 and RRM2, were validated and their inhibition mediated by gemcitabine or hydroxyurea respectively, was more cytotoxic in BAP1-proficient cell lines. Upregulation of RRM2 upon gemcitabine and hydroxyurea was more profound in BAP1 mut/del cell lines. Increased lethality mediated by gemcitabine and hydroxyurea was observed in NCI-H2452 cells reconstituted with BAP1 WT but not with C91A mutant and upregulation of RRM2 in NCI-H2452-BAP1 WT spheroids was modest compared to control or C91A mutant. Finally, the opposite was observed after BAP1 knockdown in BAP1-proficient SPC111 cell line.Conclusion We found that BAP1 is involved in the regulation of RRM2 levels during replication stress. These observations reveal a potential therapeutic approach where MPM patients to be stratified depending on BAP status for gemcitabine treatment.