Dokument: Decrypting the role of HSP90α and β isoforms in BCR-ABL1+ leukemia and Characterization of Small Molecule HSP90 Inhibitors and Degraders
| Titel: | Decrypting the role of HSP90α and β isoforms in BCR-ABL1+ leukemia and Characterization of Small Molecule HSP90 Inhibitors and Degraders | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=67802 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20241204-105857-5 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Vogt, Melina [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Borkhardt, Arndt [Gutachter] Prof. Dr. Kurz, Thomas [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 570 Biowissenschaften; Biologie | |||||||
| Beschreibung: | Heat shock protein 90 (HSP90) is involved in various cellular processes and fulfils a crucial role as a molecular chaperone in the folding, stabilization, and regulation of client proteins. Their role in stabilizing oncoproteins, such as BCR-ABL1 and increased expression in cancer cells makes HSP90 a promising therapeutic target. Despite tremendous treatment success using tyrosine kinase inhibitors (TKIs), the prognosis in the BCR-ABL1+ leukemia subtype is unfavourable and treatment-free remission is limited, leading to the ongoing occurrence of resistance. Various inhibitors targeting the N-terminal domain (NTD) of HSP90 have been developed but have shown limited clinical benefit. This is mainly due to the induction of the pro-survival resistance mechanism, the heat shock response (HSR) and dose-limiting toxicity. This study aims to tackle the prevailing issues related to HSP90 inhibitor therapy through (i) com-prehending the influence of cytosolic HSP90 isoforms (HSP90α and HSP90β) in the development of resistance and (ii) advancing the progression of C-terminal domain (CTD) targeting HSP90 inhibitors, which have been recognized to prevent HSR induction.
(i) CRISPR/CAS9 or siRNA-mediated targeting of (constitutively expressing) HSP90β isoform resulted in an enhanced HSR and demonstrated consistent upregulation of the inducible iso-form, HSP90α. Deletion of HSP90α resulted in an increase in BCR-ABL1 activity and associated pro-survival signalling. Interestingly, previously reported client proteins of HSP90α/β, such as CDK4, CDK6, and SURVIVIN, showed no altered expression in HSP90α/β-KO cells. When HSP90α/β-KO cells were transplanted into mice, there was a notable reduction in the transplantation efficiency specifically observed in HSP90α-KO cells, which was confirmed by the prolonged survival of mice. Proteogenomic profiling, including RNA sequencing, mass spectrometry, and secretome analysis, provided insights into molecular mechanisms and revealed differences in HSP90α/β-KO cells. Upon the ablation of HSP90α, a decrease in PTPRC (CD45) and LCK expression was observed in BCR-ABL1+ leukemia cells. Furthermore, in-creased sensitivity of HSP90α-KO cells to CDK7 inhibition was identified. Notably, combined inhibition of HSP90 and CDK7 displayed synergistic effects against therapy-resistant BCR-ABL1+ leukemia cells, blocking pro-survival HSR and HSP90α overexpression. (ii) This research builds on an existing strategy that specifically targets HSP90 CTD dimerization by employing novel protein-protein interaction inhibitors. Biochemical and biophysical assays showed that the inhibitors (α-helix mimetics based on substituted pyrimidine and pyrimidone amides) bind and disrupt the CTD dimerization interface of HSP90. Remarkably, the inhibitors 2 (VWK346) and 3 (VWK141) showed anti-leukemic activity against CML and ALL leukemia cell lines and patient-derived leukemia cells. As an alternative approach for targeting HSP90, first-in-class cereblon-recruiting Geldanamycin-based Proteolysis targeting chimeras (PROTACs) were evaluated. These PROTACs demonstrated successful degradation of HSP90α and HSP90β, offering a promising approach to circumvent HSP90 inhibitor-induced resistance. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät | |||||||
| Dokument erstellt am: | 04.12.2024 | |||||||
| Dateien geändert am: | 04.12.2024 | |||||||
| Promotionsantrag am: | 14.02.2024 | |||||||
| Datum der Promotion: | 18.11.2024 |
