Thrombospondin-1 counteracts the p97 inhibitor CB-5083 in colon carcinoma cells.
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ABSTRACT:
SUBMITTER: Her NG
PROVIDER: S-EPMC7469669 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The goal of this study was to analyze differential gene expression 8 hr after treatment of CB-5083, a small molecule inhibitor of p97 (VCP), in HCT116 cells grown in culture.
2015-11-09 | GSE73588 | GEO
Project description:Small-molecule inhibitors of p97 are useful tools to study p97 function. Human p97 is an important AAA ATPase due to its diverse cellular functions and implication in mediating the turnover of proteins involved in tumorigenesis and virus infections. Multiple p97 inhibitors identified from previous high-throughput screening studies are thiol-reactive compounds targeting Cys522 in the D2 ATP-binding domain. Thus, these findings suggest a potential strategy to develop covalent p97 inhibitors. We first used purified p97 to assay several known covalent kinase inhibitors to determine if they can inhibit ATPase activity. We evaluated their selectivity using our dual reporter cells that can distinguish p97 dependent and independent degradation. We selected a β-nitrostyrene scaffold to further study the structure-activity relationship. In addition, we used p97 structures to design and synthesize analogues of pyrazolo[3,4-d]pyrimidine (PP). We incorporated electrophiles into a PP-like compound 17 (4-amino-1-tert-butyl-3-phenyl pyrazolo[3,4-d]pyrimidine) to generate eight compounds. A selective compound 18 (N-(1-(tert-butyl)-3-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)acrylamide, PPA) exhibited excellent selectivity in an in vitro ATPase activity assay: IC50 of 0.6 μM, 300 μM, and 100 μM for wild type p97, yeast Cdc48, and N-ethylmaleimide sensitive factor (NSF), respectively. To further examine the importance of Cys522 on the active site pocket during PPA inhibition, C522A and C522T mutants of p97 were purified and shown to increase IC50 values by 100-fold, whereas replacement of Thr532 of yeast Cdc48 with Cysteine decreased the IC50 by 10-fold. The molecular modeling suggested the hydrogen bonds and hydrophobic interactions in addition to the covalent bonding at Cys522 between WT-p97 and PPA. Furthermore, tandem mass spectrometry confirmed formation of a covalent bond between Cys522 and PPA. An anti-proliferation assay indicated that the proliferation of HCT116, HeLa, and RPMI8226 was inhibited by PPA with IC50 of 2.7 μM, 6.1 μM, and 3.4 μM, respectively. In addition, PPA is able to inhibit proliferation of two HCT116 cell lines that are resistant to CB-5083 and NMS-873, respectively. Proteomic analysis of PPA-treated HCT116 revealed Gene Ontology enrichment of known p97 functional pathways such as the protein ubiquitination and the ER to Golgi transport vesicle membrane. In conclusion, we have identified and characterized PPA as a selective covalent p97 inhibitor, which will allow future exploration to improve the potency of p97 inhibitors with different mechanisms of action.
| S-EPMC7954469 | biostudies-literature
Project description:BackgroundPathogenic gain of function variants in Valosin-containing protein (VCP) cause a unique disease characterized by inclusion body myopathy with early-onset Paget disease of bone and frontotemporal dementia (also known as Multisystem proteinopathy (MSP)). Previous studies in drosophila models of VCP disease indicate treatment with VCP inhibitors mitigates disease pathology. Earlier-generation VCP inhibitors display off-target effects and relatively low therapeutic potency. New generation of VCP inhibitors needs to be evaluated in a mouse model of VCP disease. In this study, we tested the safety and efficacy of a novel and potent VCP inhibitor, CB-5083 using VCP patient-derived myoblast cells and an animal model of VCP disease.MethodsFirst, we analyzed the effect of CB-5083 in patient-derived myoblasts on the typical disease autophagy and TDP-43 profile by Western blot. Next, we determined the maximum tolerated dosage of CB-5083 in mice and treated the 2-month-old VCPR155H/R155H mice for 5 months with 15 mg/kg CB-5083. We analyzed motor function monthly by Rotarod; and we assessed the end-point blood toxicology, and the muscle and brain pathology, including autophagy and TDP-43 profile, using Western blot and immunohistochemistry. We also treated 12-month-old VCPR155H/+ mice for 6 months and performed similar analysis. Finally, we assessed the potential side effects of CB-5083 on retinal function, using electroretinography in chronically treated VCPR155H/155H mice.ResultsIn vitro analyses using patient-derived myoblasts confirmed that CB-5083 can modulate expression of the proteins in the autophagy pathways. We found that chronic CB-5083 treatment is well tolerated in the homozygous mice harboring patient-specific VCP variant, R155H, and can ameliorate the muscle pathology characteristic of the disease. VCP-associated pathology biomarkers, such as elevated TDP-43 and p62 levels, were significantly reduced. Finally, to address the potential adverse effect of CB-5083 on visual function observed in a previous oncology clinical trial, we analyzed retinal function in mice treated with moderate doses of CB-5083 for 5 months and documented the absence of permanent ocular toxicity.ConclusionsAltogether, these findings suggest that long-term use of CB-5083 by moderate doses is safe and can improve VCP disease-associated muscle pathology. Our results provide translationally relevant evidence that VCP inhibitors could be beneficial in the treatment of VCP disease.
| S-EPMC8742393 | biostudies-literature
Project description:The goal of this study was to analyze differential gene expression 8 hr after treatment of CB-5083, a small molecule inhibitor of p97 (VCP), in HCT116 cells grown in culture. DMSO treated cells were compared to cells treated with 1uM CB-5083 after 8 hr.
2015-11-09 | E-GEOD-73588 | biostudies-arrayexpress
Project description:Inhibition of p97, a key player in the ubiquitin-proteasome degradation pathway, has been proposed as a treatment of cancer. This concept was nearly realized recently when a potent p97 inhibitor, 1-[4-(benzylamino)-5H,7H,8H-pyrano[4,3-d]pyrimidin-2-yl]-2-methyl-1H-indole-4-carboxamide (CB-5083), was developed and demonstrated broad antitumor activity in various tumor models. CB-5083 functions as a competitive inhibitor that binds selectively to the ATP-binding site of the D2 domain, although both the D1 and D2 ATPase sites of p97 are highly similar. Despite its promising anticancer activity, CB-5083 failed its phase I clinical trials due to an unexpected off-target effect, which necessitates further improvement of the inhibitor. In this study, we determined the crystal structure of N-terminal domain-truncated p97 in complex with CB-5083. It provides a structural basis for the specificity of CB-5083 toward the D2 domain, offers an explanation in atomic detail for the mutations that confer resistance to CB-5083, and establishes a foundation for future structure-guided efforts to develop the next generation of p97 inhibitors.
| S-EPMC6355941 | biostudies-literature
Project description:CB-5083 is an inhibitor of p97/valosin-containing protein (VCP), for which phase I trials for cancer were terminated because of adverse effects on vision, such as photophobia and dyschromatopsia. Lower dose CB-5083 could combat inclusion body myopathy with early-onset Paget disease and frontotemporal dementia or multisystem proteinopathy caused by gain-of-function mutations in VCP. We hypothesized that the visual impairment in the cancer trial was due to CB-5083's inhibition of phosphodiesterase (PDE)-6, which mediates signal transduction in photoreceptors. To test our hypothesis, we used in vivo and ex vivo electroretinography (ERG) in mice and a PDE6 activity assay of bovine rod outer segment (ROS) extracts. Additionally, histology and optical coherence tomography were used to assess CB-5083's long-term ocular toxicity. A single administration of CB-5083 led to robust ERG signal deterioration, specifically in photoresponse kinetics. Similar recordings with known PDE inhibitors sildenafil, tadalafil, vardenafil, and zaprinast showed that only vardenafil had as strong an effect on the ERG signal in vivo as did CB-5083. In the biochemical assay, CB-5083 inhibited PDE6 activity with a potency higher than sildenafil but lower than that of vardenafil. Ex vivo ERG revealed a PDE6 inhibition constant of 80 nM for CB-5083, which is 7-fold smaller than that for sildenafil. Finally, we showed that the inhibitory effect of CB-5083 on visual function is reversible, and its chronic administration does not cause permanent retinal anomalies in aged VCP-disease model mice. Our results warrant re-evaluation of CB-5083 as a clinical therapeutic agent. We recommend preclinical ERG recordings as a routine drug safety screen. SIGNIFICANCE STATEMENT: This report supports the use of a valosin-containing protein (VCP) inhibitor drug, CB-5083, for the treatment of neuromuscular VCP disease despite CB-5083's initial clinical failure for cancer treatment due to side effects on vision. The data show that CB-5083 displays a dose-dependent but reversible inhibitory action on phosphodiesterase-6, an essential enzyme in retinal photoreceptor function, but no long-term consequences on retinal function or structure.
| S-EPMC8456514 | biostudies-literature
Project description:The goal was to determine the gene expression differences between CB-5083 and Bortezomib treated multiple myeloma cell lines Inhibition of the AAA ATPase, p97, was recently shown to be a novel method for targeting the ubiquitin proteasome system (UPS) and CB-5083, a first in class inhibitor of p97, has demonstrated broad antitumor activity in a range of both hematological and solid tumor models. Here, we show that CB-5083 has robust activity against multiple myeloma (MM) cell lines and a number of in vivo MM models. Treatment with CB-5083 is associated with accumulation of ubiquitinated proteins, induction of the unfolded protein response (UPR) and apoptosis. CB-5083 decreases viability in MM cell lines and patient derived MM cells, including those with background proteasome inhibitor (PI) resistance. CB-5083 has a unique mechanism of action that combines well with PIs which is likely owing to the p97-dependent retro-translocation of the transcription factor, Nrf1, which transcribes proteasome subunit genes following exposure to a PI. In vivo studies using clinically relevant MM models demonstrate that single-agent CB-5083 inhibits tumor growth and combines well with MM standard of care agents. Our preclinical data demonstrate the efficacy of CB-5083 in several MM disease models and provide the rationale for clinical evaluation as monotherapy and in combination in MM.
2017-10-26 | GSE101923 | GEO
Project description:Curative responses in the treatment of multiple myeloma (MM) are limited by the emergence of therapeutic resistance. To address this problem, we set out to identify druggable mechanisms that convey resistance to proteasome inhibitors (PIs; e.g., bortezomib), which are cornerstone agents in the treatment of MM. In isogenic pairs of PI sensitive and resistant cells, we observed stark differences in cellular bioenergetics between the divergent phenotypes. PI resistant cells exhibited increased mitochondrial respiration driven by glutamine as the principle fuel source. To target glutamine-induced respiration in PI resistant cells, we utilized the glutaminase-1 inhibitor, CB-839. CB-839 inhibited mitochondrial respiration and was more cytotoxic in PI resistant cells as a single agent. Furthermore, we found that CB-839 synergistically enhanced the activity of multiple PIs with the most dramatic synergy being observed with carfilzomib (Crflz), which was confirmed in a panel of genetically diverse PI sensitive and resistant MM cells. Mechanistically, CB-839 enhanced Crflz-induced ER stress and apoptosis, characterized by a robust induction of ATF4 and CHOP and the activation of caspases. Our findings suggest that the acquisition of PI resistance involves adaptations in cellular bioenergetics, supporting the combination of CB-839 with Crflz for the treatment of refractory MM.
| S-EPMC5482623 | biostudies-literature
Project description:The goal of this experiment is to identify differentially expressed genes between parental OVSAHO cells and CB-5083-resistant OVSAHO cells. Each group is treated with 5 microM CB-5083 for 6 hours and total RNA was extracted with Trizol. RNA sequencing library was performed using Illumina RNA library kit.
2018-11-02 | E-MTAB-7328 | biostudies-arrayexpress
Project description:We previously found that p97 ATPase inhibitors 2-(2-amino-1H-benzo[d]imidazol-1-yl)-N-benzyl-8-methoxyquinazolin-4-amine (ML240) and 2-(2H-benzo[b][1,4]oxazin-4(3H)-yl)-N-benzyl-5,6,7,8-tetrahydroquinazolin-4-amine (ML241) specifically target the D2 domain of wild-type p97. In addition, one of the major p97 cofactors, p47, decreases their potencies by ?50-fold. In contrast, N(2) ,N(4) -dibenzylquinazoline-2,4-diamine (DBeQ) targets both the D1 and D2 domains and shows only a four- to sixfold decrease in potency against the p97-p47 complex. To elucidate structure-activity relationships for the inhibitors, we screened 200 p97 inhibitor analogues for their ability to inhibit the ATPase activity of either or both of the D1 or D2 domains, as well for their effects on p47 potency. The selectivity of 29 of these compounds was further examined by eight-dose titrations. Four compounds showed modest selectivity for inhibiting the ATPase activity of D1. Eleven compounds inhibited D2 with greater potencies, and four showed similar potencies against D1 and D2. p47 decreased the potencies of the majority of the compounds and increased the potencies of five compounds. These results highlight the possibility of developing domain-selective and complex-specific p97 inhibitors in order to further elucidate the physiological roles of p97 and its cofactors.
| S-EPMC4280364 | biostudies-literature