The purine scaffold HSP90 inhibitor PU-H71 induces specific changes in gene expression in DLBCL xenografts.
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE13401 | GEO | 2009/11/15
SECONDARY ACCESSION(S): PRJNA109759
REPOSITORIES: GEO
Similar Datasets
Project description:Heat shock protein 90 (Hsp90) is an emerging therapeutic target in cancer. We report that Hsp90 inhibitors selectively kill DLBCLs that are biologically dependent on the BCL6 transcriptional repressor. We examined the pharmacokinetics, toxicity and efficacy of PUH71, a recently developed purine scaffold Hsp90 inhibitor. PUH71 preferentially accumulated in tumors vs. normal tissues, and unlike the widely used benzoquinone Hsp90 inhibitors, displayed no signs of organ toxicity. PUH71 selectively and potently induced the regression of BCL6-dependent DLBCLs in vivo, through reactivation of key BCL6 target genes and apoptosis. Experiment Overall Design: Six SCID mice were subcutaneously injected with human Farage DLBCL cells. When tumors reached 1 cm in diameter, four mice were administered PU-H71 (75mg/kg) by intra-peritoneal injection and two mice served as no-treatment controls. Animals were sacrificed by cervical dislocation under anesthesia at 6 and 12 h after the administration of PU-H71.
2009-11-28 | E-GEOD-13401 | biostudies-arrayexpress
Project description:Aggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo. We found that eIF4E activity regulates the nuclear export of BCL6, MYC, and BCL2 in DH/TH DLBCLs. To determine the extent of nuclear eIF4E activity in DH/TH DLBCLs and how these programs can support the oncogenic activity of BCL6, MYC and/or BCL2 transcripts, we conducted eIF4E-RIP of nuclear RNA followed by RNA-sequencing in OCI-Ly1 cells in triplicates. To understand the changes in gene expression after ribavarin in a clinically relevant sample, we generated a patient-derived xenograft (PDX) in NSG mice from a de-identified specimen isolated from a patient prior to treatment harboring a triple-hit ABC-type DLBCL. PDX cells from passage four (PDX-4) were implanted into NSG mice. When tumors were palpable, mice were randomized to receive vehicle or 80 mg/kg/b.i.d. ribavarin intraperitoneally for 10 days. We isolated RNA from tumors treated with vehicle (n=2) or ribavarin (n=2) and performed mRNA-seq.
2016-01-11 | E-GEOD-63265 | biostudies-arrayexpress
Project description:Using 4 primary melanoma cell lines for which autologous tumor-infiltrating T lymphocytes (TILs) were available, a screen of clinically-relevant small-molecule inhibitors (SMIs) was performed to find SMIs that could synergistically enhance tumor cell killing by autologous TILs. Among positive results were SMIs targeting topoisomerase I (TOP1) or HSP90. Of note, as implied by the fact that these SMIs had synergistic effects, there was relatively little direct cytotoxicity of the SMIs when used alone. Gene expression profiling was undertaken to identify changes induced by SMIs of TOP1 or HSP90. SN38 is the active metabolite of irinotecan, a standard-of-care clinical TOP1 inhibitor. Ganetespib is a newer generation HSP90 inhibitor, reported to exhibit greater potency in preclinical tumor models and reduced toxicity in rodents, compared to other 1st and 2nd generation HSP90 inhibitors, consistent with its favorable safety profile in patients.
2017-10-04 | GSE100317 | GEO
Project description:The BCL6 transcriptional repressor is a critical oncogene in diffuse large B-cell lymphomas (DLBCL). The specific BCL6 inhibitor RI-BPI potently kills DLBCL cells. We find that RI-BPI induces a particular gene expression signature in DLBCL. In order to identify classes of drugs that might synergize with RIBPI we examined the connectivity of this signature and found a strong association with HDAC and Hsp90 inhibitors. This was explained by the discovery that BCL6 directly represses the p300 lysine acetyltransferase and its co-factor BAT3. RI-BPI induced expression of p300 and BAT3, and p300 acetyltransferase activity, resulting in acetylation of p300 targets like p53 and Hsp90. As a consequence, RI-BPI could attenuate Hsp90 chaperone function, similar to the effect of Hsp90 and HDAC inhibitors. Induction of p300 and BAT3 was required for the anti-lymphoma effects of RI-BPI since specific blockade of either protein rescued DLBCL cells from the BCL6 inhibitor. RI-BPI synergistically killed DLBCL cells in combination with HDAC inhibitors (SAHA, TSA and VPA) and Hsp90 inhibitors (17-DMAG and PUH71). The combination of RI-BPI and SAHA, or RI-BPI and PU-H71 potently suppressed or even eradicated human DLBCL in mice. BCL6 repression of EP300 thus provides a basis for rational targeted combinatorial therapy for patients with DLBCL. Direct comparison of gene expression levels in DLBCL cell lines after 24hs of treatment with either a Bcl6 inhibitor peptide or control peptide
2010-09-21 | E-GEOD-24236 | biostudies-arrayexpress
Project description:Rationale: The BCL6 oncogene is constitutively activated by chromosomal translocations and amplification in ABC-DLBCLs, a class of DLBCLs that respond poorly to current therapies. Yet the role of BCL6 in maintaining these lymphomas has not been investigated. BCL6 mediates its effects by recruiting corepressors to an extended groove motif. Development of effective BCL6 inhibitors requires compounds exceeding the binding affinity of these corepressors. Objectives: To design small molecule inhibitors with superior potency vs. endogenous BCL6 ligands for unmet putative therapeutic needs such as targeting ABC-DLBCL. Findings: We used an in silico drug design functional-group mapping approach called SILCS to create a specific BCL6 inhibitor with 10-fold greater potency than endogenous corepressors. The compound, called FX1, binds in such a way as to occupy an essential region of the BCL6 lateral groove. FX1 disrupts BCL6 repression complex formation, reactivates BCL6 target genes, and mimics the phenotype of mice engineered to express BCL6 with lateral groove mutations. This compound eradicated established DLBCLs xenografts at low doses. Most strikingly, FX1 suppressed ABC-DLBCL cells as well as primary human ABC-DLBCL specimens ex vivo. Conclusions: ABC-DLBCL is a BCL6 dependent disease that can be targeted by novel inhibitors able to exceed the binding affinity of natural BCL6 ligands.
2016-10-12 | GSE80351 | GEO
Project description:Low response rates and immune-related adverse events limit the impact of cancer immunotherapy. In the quest for improved clinical outcomes, preclinical studies have shown that combining immune checkpoint blockade therapies with N-terminal Hsp90 inhibitors resulted in improved efficacy, even though induction of an extensive heat shock response (HSR) with these inhibitors limited their clinical efficacy as monotherapies. We discovered that Enniatin A (EnnA) binds to the interface between the middle domains of the Hsp90 dimer and destabilizes Hsp90 client oncoproteins without inducing an HSR. We found that EnnA induces cancer cell immunogenic cell death in aggressive breast cancer models and exhibits superior anti-tumor activity compared to Hsp90 N-terminal inhibitors. Further, we show that EnnA reprograms the tumor microenvironment in syngeneic mouse models to promote CD8+ T cell-dependent anti-tumor activity mediated through the CX3CR1 signaling pathway. We propose that EnnA is a promising anti-tumor agent with a novel mechanism of action involving immunogenic cancer cell toxicity and the mobilization of CD8+ T cells into the tumor site.
2023-09-21 | GSE168875 | GEO
Project description:Genetic analysis of K562 cell which are resistant against HSP90 inhibitors.
| EGAS00001006381 | EGA
Project description:The BCL6 transcriptional repressor is a critical oncogene in diffuse large B-cell lymphomas (DLBCL). The specific BCL6 inhibitor RI-BPI potently kills DLBCL cells. We find that RI-BPI induces a particular gene expression signature in DLBCL. In order to identify classes of drugs that might synergize with RIBPI we examined the connectivity of this signature and found a strong association with HDAC and Hsp90 inhibitors. This was explained by the discovery that BCL6 directly represses the p300 lysine acetyltransferase and its co-factor BAT3. RI-BPI induced expression of p300 and BAT3, and p300 acetyltransferase activity, resulting in acetylation of p300 targets like p53 and Hsp90. As a consequence, RI-BPI could attenuate Hsp90 chaperone function, similar to the effect of Hsp90 and HDAC inhibitors. Induction of p300 and BAT3 was required for the anti-lymphoma effects of RI-BPI since specific blockade of either protein rescued DLBCL cells from the BCL6 inhibitor. RI-BPI synergistically killed DLBCL cells in combination with HDAC inhibitors (SAHA, TSA and VPA) and Hsp90 inhibitors (17-DMAG and PUH71). The combination of RI-BPI and SAHA, or RI-BPI and PU-H71 potently suppressed or even eradicated human DLBCL in mice. BCL6 repression of EP300 thus provides a basis for rational targeted combinatorial therapy for patients with DLBCL.
2010-09-21 | GSE24236 | GEO
Project description:HSP90 inhibitors (HSP90i) have not entered routinely in the clinics, primarily due to the associated resistance via heat shock response (HSR) induction and dose limiting toxicity. In this study, we employed genetic KO and knockdown (KD) models of HSP90 isoforms (α and β) for extensive multi-omics-based in vitro and in vivo characterization and identified HSP90α as the primary driver of malignancy of the two isoforms in BCR-ABL1+ leukemia cells. Notably, combinatorial ex vivo drug sensitivity screenings identified CDK7 inhibitors (CDK7i) as drugs synergizing with HSP90α inhibition.
2024-01-26 | PXD041871 | Pride
Project description:Background. Heat shock protein 90 (Hsp90) is essential for the stability and the function of many client proteins, such as ERB2, C-RAF, CDK4, HIF-1 aplha and AKT. Recent reports demonstrated that inhibition of Hsp90 modulates multiple functions required for survival of human cancer, such as myeloma (Mitsiades et al, Blood:107, 1092, 2006), however, the precise mechanism of anti-cancer effect of Hsp90 inhibition is still uncertain. Aim. The aim of this study is evaluate the effect of Hsp90 inhibition, and to identify molecular pathways responsible for anti-proliferative effect on ATL cells. Method. For Hsp90 inhibition, Geldanamycin derivates, 17AAG (17-allylamino -17-demethoxygeldanamycin) and 17DMAG (17-(dimethylaminoethylamino) 17-demethoxygeldanamycin) were used in this study. Interleukin 2-independent ATL cell lines (MT-2 and MT-4) and an interleukin 2-dependent ATL cell line (TaY) were incubated, with or without Hsp90 inhibitors. Fresh ATL cells obtained from patients were also used after obtaining informed consent. Cell numbers at 48 h after incubation with or without Hsp90 inhibitors were assessed with the Cell Counting Kit-8 assay (Dojindo Molecular Technologies, Gaithersburg, MD, USA). For detection of apoptosis, we used Annexin V-biotin apoptosis detection kit (Calbiochem, La Jolla, CA, USA). Gene expression analysis was done using a DNA microarray (NCBI Gene expression omnibus; GPL 2531) and statistical analysis was done by a GeneSifter (VizXlabs, Seattle, WA, USA). Results. We found cell death induced by Hsp90 inhibitors in all the 3 ATL cell lines as well as patient specimens. Inhibitory concentration (IC50) of 17AAG in 3 ATL cell lines was 300 to 700 nM, and that of 17DMAG was 150 to 200 nM. Fresh ATL cells obtained from patients were more sensitive for either 17AAG or 17DMAG. Gene expression analysis of ATL cells revealed that up-regulation of HSPA1A encoding Hsp70, and genes related to cell cycle arrest (i.e. CDKN1A). Genes regulating cell proliferation or anti-apoptosis (i.e. MYC, BCL2 and Cyclin C), genes related to cytokine or chemokine (i.e. IL9, CCL 17, and CCL27), and notably, genes involved in Wnt/-catenin signaling pathway (i.e.TCF7L2 and TCF4), were remarkably repressed. Inhibition of AKT at the protein level was also evident, suggesting the possibility that AKT may down-regulates -catenin/ TCF7L2 pathways in response to Hsp90 inhibitors in ATL cells. Conclusion. Our results have provided new insights into the complex molecular pharmacology of Hsp90 inhibitors, and suggest that Hsp90 inhibitors might be beneficial as anti-proliferative agent in treating ATL patients. Six samples treated with Hsp90 inhibitors (17-AAG or 17-DMAG) were analyzed in biological duplicate.
2009-05-27 | E-GEOD-12257 | biostudies-arrayexpress