Allosteric HSP70 inhibitors perturb mitochondrial proteostasis and overcome proteasome inhibitor resistance in multiple myeloma
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PROVIDER: PRJNA625299 | ENA |
REPOSITORIES: ENA
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Project description:Proteasome inhibitor (PI) resistance remains a central challenge in multiple myeloma. To identify pathways mediating resistance, we first map proteasome-associated genetic co-dependencies. We identify cytosolic heat shock protein 70 (HSP70) chaperones as a potential target, consistent with proposed mechanisms of myeloma tumor cells overcoming PI-induced stress. These results led us to explore allosteric HSP70 inhibitors as myeloma therapeutics. We show these compounds exhibit increased efficacy against both acquired and intrinsic PI-resistant myeloma models, unlike HSP90 inhibition. Surprisingly, shotgun and pulsed-SILAC proteomics reveal that JG’s overcome PI resistance not via the expected mechanism of inhibiting cytosolic HSP70s, but instead through mitochondrial-localized HSP70, HSPA9, destabilizing the 55S mitoribosome. Analysis of myeloma patient data further supports strong effects of global proteostasis capacity, and particularly HSPA9 expression, on PI response. Our results characterize dynamics of myeloma proteostasis networks under therapeutic pressure while further motivating investigation of HSPA9 as a specific target in PI-resistant disease.
2020-04-15 | GSE148659 | GEO
Project description:Proteasome inhibitor (PI) resistance remains a central challenge in multiple myeloma. To identify pathways mediating this resistance, we mapped genetic co-dependencies associated with the proteasome. These studies identified cytosolic heat shock protein 70 (HSP70) chaperones as a potential target, mirroring recent studies that have shown mechanism of overcoming PI-induced stress. Here, we first underscore this relationship by mapping genetic co-dependencies in cancer proteostasis. These results lead us to explore HSP70 inhibitors as potential therapeutics. We show these compounds exhibit increased efficacy against both acquired and intrinsic PI-resistant myeloma models, unlike HSP90 inhibition. Surprisingly, shotgun and pulsed-SILAC proteomics reveal that JG’s overcome PI resistance not via the expected mechanism of inhibiting cytosolic HSP70s, but instead through mitochondrial-localized HSP70, HSPA9, destabilizing the 55S mitoribosome. Analysis of myeloma patient data further supports strong effects of global proteostasis capacity, and particularly HSPA9 expression, on response to PI. Our results characterize dynamics of myeloma proteostasis networks under therapeutic pressure while further motivating investigation of HSPA9 as a specific target in PI-resistant disease. This dataset corresponds to figure 5, experiment outlined in figure 5a.
2020-04-24 | PXD018387 | Pride
Project description:Proteasome inhibitor (PI) resistance remains a central challenge in multiple myeloma. To identify pathways mediating this resistance, we mapped genetic co-dependencies associated with the proteasome. These studies identified cytosolic heat shock protein 70 (HSP70) chaperones as a potential target, mirroring recent studies that have shown mechanism of overcoming PI-induced stress. Here, we first underscore this relationship by mapping genetic co-dependencies in cancer proteostasis. These results lead us to explore HSP70 inhibitors as potential therapeutics. We show these compounds exhibit increased efficacy against both acquired and intrinsic PI-resistant myeloma models, unlike HSP90 inhibition. Surprisingly, shotgun and pulsed-SILAC proteomics reveal that JG’s overcome PI resistance not via the expected mechanism of inhibiting cytosolic HSP70s, but instead through mitochondrial-localized HSP70, HSPA9, destabilizing the 55S mitoribosome. Analysis of myeloma patient data further supports strong effects of global proteostasis capacity, and particularly HSPA9 expression, on response to PI. Our results characterize dynamics of myeloma proteostasis networks under therapeutic pressure while further motivating investigation of HSPA9 as a specific target in PI-resistant disease. This dataset corresponds to experiment outlined in figure 4a.
2020-04-24 | PXD018617 | Pride
Project description:Proteasome inhibitor (PI) resistance remains a central challenge in multiple myeloma. To identify pathways mediating resistance, we first mapped proteasome-associated genetic co-dependencies. We identified cytosolic heat shock protein 70 (HSP70) chaperones as potential targets, consistent with proposed mechanisms of myeloma tumor cells overcoming PI-induced stress. These results led us to explore allosteric HSP70 inhibitors (JG compounds) as myeloma therapeutics. We showed these compounds exhibit increased efficacy against acquired and intrinsic PI-resistant myeloma models, unlike HSP90 inhibition. Surprisingly, shotgun and pulsed-SILAC mass spectrometry found that JGs have the most pronounced effect on the proteome not through inhibiting cytosolic HSP70s but instead through mitochondrial-localized HSP70, HSPA9/mortalin, destabilizing the 55S mitoribosome. Analysis of myeloma patient data further supports strong effects of global proteostasis capacity, and particularly HSPA9 expression, on PI response. Our results characterize myeloma proteostasis networks under therapeutic pressure while motivating further investigation of HSPA9 as a specific vulnerability in PI-resistant disease.
2022-05-27 | PXD032030 | Pride
Project description:Constitutively active androgen receptor (AR) signaling confers resistance to AR-targeted therapies. Here we show that the ubiquitin-mediated proteolysis pathway plays a critical role in the degradation of AR and its variants, particularly variant 7 (AR-V7). AR/AR-V7 proteinhomeostasis (proteostasis) requires interaction of the E3 ubiquitin ligase STUB1 and HSP70complex. STUB1 disassociates AR/AR-V7 from HSP70, leading to AR/AR-V7 ubiquitination and degradation. Inhibition of HSP70 reduces AR/AR-V7 expression which significantly inhibits prostate tumor growth and improves enzalutamide/abiraterone treatments. Clinically, HSP70 expression is upregulated and correlated with AR/AR-V7 levels in high Gleason scores prostate tumors. Our results reveal a novel mechanism of AR-V7 modulation via proteostasis which could be targeted to reduce AR-V7 expression and overcome resistance to AR-targeted therapies.
2018-10-05 | GSE120005 | GEO
Project description:Constitutively active androgen receptor (AR) signaling confers resistance to AR-targeted therapies. Here we show that the ubiquitin-mediated proteolysis pathway plays a critical role in the degradation of AR and its variants, particularly variant 7 (AR-V7). AR/AR-V7 proteinhomeostasis (proteostasis) requires interaction of the E3 ubiquitin ligase STUB1 and HSP70complex. STUB1 disassociates AR/AR-V7 from HSP70, leading to AR/AR-V7 ubiquitination and degradation. Inhibition of HSP70 reduces AR/AR-V7 expression which significantly inhibits prostate tumor growth and improves enzalutamide/abiraterone treatments. Clinically, HSP70 expression is upregulated and correlated with AR/AR-V7 levels in high Gleason scores prostate tumors. Our results reveal a novel mechanism of AR-V7 modulation via proteostasis which could be targeted to reduce AR-V7 expression and overcome resistance to AR-targeted therapies.
2018-10-05 | GSE120004 | GEO
Project description:Enzymes catalyze the reactions of life and are the targets of nearly all small molecule drugs. Most drugs inhibit enzymes by binding to conserved active sites, causing problems of specificity and toxicity. Targeting regulatory allosteric sites can increase specificity, overcome drug resistance and tune or activate activity.However, the vast majority of enzymes have no known allosteric sites and methods do not exist to globally identify or predict them.Here we present a general and fast method to globally chart allosteric communication in enzymes and apply it to the Src protein kinase to produce the first comprehensive map of negative and positive allosteric control of enzymatic activity. Allosteric control of Src is pervasive, anisotropic and distance dependent, but fairly predictable from simple sequence and structural features. The comprehensive allosteric map enables unbiased identification of all the allosterically active surface pockets of the Src kinase for the development of activatory and inhibitory drugs.This general approach can be used to chart global allosteric maps of many kinases, enzymes, and other biochemical activities important for medicine and biotechnology.
2024-04-27 | GSE247740 | GEO
Project description:The major heat shock protein Hsp70 has been shown to form a complex with a scaffold protein Bag3, linking it to multiple signaling pathways. Via these interactions, the Hsp70-Bag3 module functions as a proteotoxicity sensor that controls cell signaling. Here, as a tool to identify signaling pathways regulated by this complex, we utilized JG-98, an allosteric inhibitor of Hsp70 that blocks its interaction with Bag3. Gene expression profiling followed by the pathway analysis indicated that a set of signaling pathways including the unfolded protein response (UPR) was activated by JG-98. Surprisingly, only the translation initiation factor eIF2a-associated branch of the UPR was activated under these conditions, while other UPR branches mediating induction of ER chaperones were not induced, suggesting that the response was not related to ER proteotoxicity and thus to ER-associated kinase PERK1. Indeed, induction of the UPR genes under these conditions was dependent on activation of a distinct cytoplasmic eIF2a kinase, HRI. We demonstrated that the Hsp70-Bag3 complex directly interacted with HRI and regulated phosphorylation of eIF2a upon induction of cytoplasmic proteotoxicity. Therefore, we uncovered a novel signaling response, which regulates cell death upon the buildup of abnormal protein species in cytoplasm via an Hsp70-Bag3-HRI-eIF2a axis.
2021-04-14 | GSE171440 | GEO
Project description:In this study we employed a label-free global proteomics approach, with a sensitivity of over 10k quantified proteins per sample, to determine contributions of different compensatory mechanisms upon the proteasome inhibition with carfilzomib - in cells of multiple myeloma, normal fibroblasts and cancers of lung, colon and pancreas. We identified several responding pathways, while the main HSP70 family stress inducible molecular chaperones HSPA1A and HSPA1B (often addressed jointly as HSPA1A/B or simply “Hsp70”, due to nearly identical protein sequences) were the most universal proteasome inhibition responders in proteomes of all the studied cell types. Further overlap of differential proteomics with RNA-seq analysis obtained at the same condions (DMSO control vs carfilzomib treatment) and a subsequent validation showed that the proteasome inhibition-dependent induction of HSPA1A/B and other chaperone proteins in cancer cells is in fact transcription-driven.
2022-09-22 | GSE184029 | GEO
Project description:Hsp70 inhibition affects many signaling pathways. We established how these effects are translated into changes in gene expression. Hsp70 is a promising anti-cancer target, and several inhibitors of Hsp70 have been recently developed. Interest to Hsp70 inhibitors as drug prototypes is, however, somewhat hampered by potential similarity of their physiological effects to effects of already well-developed Hsp90 inhibitors. JG-98 series of inhibitors is unique in its ability to target an allosteric site in the ATPase domain of Hsp70, which disrupts its interaction with a co-chaperone Bag3 and affects a variety of signaling pathways important for cancer development and survival. Here, we used the Broad Institute Connectivity Map platform to evaluate physiological effects of JG-98, and found that these effects are dissimilar from effects of Hsp90 inhibitors, thus justifying further development of this compound series. Further, using gene expression data and ActivSignal IPAD platform, we identified pathways modulated by JG-98. Some of these pathways were affected by JG-98 in Bag3-dependent and some pathways in Bag3-independent manner, indicating multiple mechanisms of JG-98 action. Using pooled shRNA genetic screen, we established gene sets that modulate the response of cancer cells to JG-98. Based on genetic and gene expression information, we developed approaches to predict potent combinations of JG-98 with known drugs. These predictions were validated by demonstrating that proteasome, RNApol II, Akt and RTK inhibitors synergize with anti-cancer effects of JG-98. Overall, in this study we analyze unique effects of Hsp70 inhibitors of JG-98 series on cell physiology and define potential drug combinations for clinical use of these inhibitors.
2018-01-11 | GSE93542 | GEO