EN523 (EN-523) is a small molecule covalent ligand EN523 that targets a non-catalytic allosteric cysteine C23 in the K48-ubiquitin-specific deubiquitinase OTUB1, OTUB1 recruiter component of DUBTAC NJH-2-057.Deubiquitinase-targeting chimeras (DUBTACs), heterobifunctional small molecules consisting of a deubiquitinase recruiter linked to a protein-targeting ligand, to stabilize the levels of specific proteins degraded in a ubiquitin-dependent manner.

FL-18 (p97 inhibitor FL-18) is is the first small-molecule covalent inhibitor of VCP/p97 AAA ATPase with IC50 of 59.3 nM, capable of covalent engagement of p97 with proteome-wide selectivity.FL-18 showed better inhibition potency than NMS-873, a well-known p97 inhibitor.FL-18 covalently modified C522 residue in p97 and showed potent enzymatic inhibition.FL-18 showed potent inhibition towards U87MG glioma cancer cells (IC50=31 nM).FL-18 inhibited the p97 activity and induced aggregation of ubiquitinated proteins in U87MG cells.

Foldamer 33 is a small molecule HSP110 inhibitor, directly binds to the nucleotide-binding domain (NBD) of HSP110, blocks HSP110 chaperone function and colorectal cancer growth.Foldamer 33 significantly inhibit HSP110 anti-aggregating activity with IC50 of 87.8 uM.Foldamer 33 disrupts HSP110-STAT3 interaction with IC50 of 35.9 uM in competitive BLI assays.Foldamer 33 inhibits SW480 colorectal cancer cell proliferation, and (5 mg/kg) Foldamer 33 displays an anti-tumor effect (TGI of 40% and 60%) in mice bearing a colorectal cancer.

Gamitrinib is a small molecule mitochondrial Hsp90 inhibitor, selectively targets Hsp90 network in tumor mitochondria; Gamitrinibs were shown to accumulate in the mitochondria of human tumor cell lines and to inhibit Hsp90 activity by acting as ATPase antagonists. Unlike Hsp90 antagonists not targeted to mitochondria, Gamitrinibs exhibited a "mitochondriotoxic" mechanism of action, causing rapid tumor cell death and inhibiting the growth of xenografted human tumor cell lines in mice. Gamitrinib were not toxic to normal cells or tissues and did not affect Hsp90 homeostasis in cellular compartments other than mitochondria.

GSK145A is a small molecule inhibitor of SUMO-conjugating enzyme E2 with IC50 of 12.5 uM, GSK145A is competitive with the sumoylation of the TRPS1 peptide substrates.

HS-131 is an imaging probe of Hsp90 activity by linking it to a near-infrared (nIR) dye, HS131 uptake into cells correlated with cell membrane expression of Hsp90 and was used to image molecular subtypes of murine and human breast cancers in vitro and in murine models.

Hsp90 inhibitor 5b is a first-in-class, small molecule inhibitor of the C-terminal (CTD) Hsp90 dimerization with KD of 3.42 uM, IC50 of 1.3 uM against leukemia cell line K562.Hsp90 inhibitor 5b inhibits Hsp90 chaperone function, does not show any interaction with the NTD of Hsp90.Hsp90 inhibitor 5b down-regulated the phospho-BCR-ABL1 and total-BCR-ABL1 levels, as well as the related downstream signaling pathways, additionally reduced the expression of client proteins associated with Hsp90 chaperone activity, involving Akt, Stat5, and c-Myc.Hsp90 inhibitor 5b inhibited leukemic cell lines (K562, KCL22 and HL60) proliferation and induced apoptosis in a caspase 3/7 enzyme-dependent assay.Hsp90 inhibitor 5b is effective against resistant leukemia cells and in the zebrafish xenotransplantation model.

Hsp90α-IN-12h is the first Hsp90α-selective inhibitor with IC50 of 460 nM, exhibit 48-fold selectivity versus other Hsp90 isoforms.In NCI-H522 cells, Hsp90a-dependent substrates are readily degraded in the presence of Hsp90a-selective inhibitor.

iBAP-II (BAP1 inhibitor II) is a next-generation, specific small molecule inhibitor of BAP1 histone H2A deubiquitinase activity with IC50 of <0.1 ug/mL.iBAP-II displays higher affinity for BAP1 than the closest UCH family member, UCHL5, and other deubiquitinases, such as USP5, USP7, USP8, TNFAIP3-catalytic domain, USP2-catalytic domain, Otubain-1, and Ataxin3.Inhibition of BAP1 via iBAP-II reduces ASXL3 protein stability in small cell lung cancer cells, without significant changes to ASXL1 and ASXL2 protein levels.iBAP-II suppresses ASCL1 expression in NCI-H1963 cells, along with the mRNA levels involving a handful of known ASCL1 transcriptional targeted genes, such as GRP, DMPK, RNF183, SCN3A, MYCL, and CACNA1A.iBAP-II exhibited more potent cell viability inhibition activity on four different BAP1-WT SCLC cell lines than iBAP.iBAP-II (50 mg/kg/d) significantly delayed the disease progression in SCLC xenograft model.

IMP-1710 (IMP1710) is a potent, selective, covalent UCHL1 inhibitor with IC50 of 38 nM.IMP-1710 demonstrated exquisite selectivity in a cross-screening against 20 DUBs.IMP-1710 can profile activity of endogenous UCHL1 with excellent selectivity in cell types including endothelial cells (EA.hy926) and adenocarcinoma human alveolar basal epithelial cells (A549).IMP-1710 demonstrated >50% fibroblast–myofibroblast transition (FMT) inhibition (IC50=740 nM) in idiopathic pulmonary fibrosis (IPF), as well as αSMA inhibition.IMP-1710 is a powerful and selective probe to explore UCHL1 activity with potential application to substrate identification, mode of action studies, and cellular target profiling.

KH-4-43 is a small moelcule E3 CRL4 inhibitor and exhibits antitumor potential, directly and selectively binds to the purified E3 ROC1-CUL4A CTD complex with Kd of 83 nM.KH-4-43 weakly binds to the purified, highly related E3 ROC1-CUL1 CTD complex with Kd of 9.4 uM, >100-fold less potent than ROC1-CUL4A CTD, showed little effect on Ub thiol ester formation with E1/E2 Cdc34.KH-4-43 inhibited the ubiquitination of CK1α by CRL4CRBN in vitro. Treatment of cells with KH-4-43 caused accumulation of the E3 CRL4 substrate CDT1.KH-4-43 inhibited cell viability against a panel of tumor lines, NB-4, MV4-11, OVCAR-3, and CAPAN-2 cell with IC50 of 1.8, 3.0, 3.9, and 4.8 uM, respectively.KH-4-43 suppress the growth of human tumor xenografts in mice.

KUNB 31 is a potent, isoform-selective Hsp90β inhibitor with Kd of 0.18 uM, displays 50-fold selectivity over Hsp90α and Grp94; exhibits anti-proliferative activity against NCI H23, UC3, and HT-29 cancer cell lines with IC50 of 6.74 µM, 3.01 µM, and 3.72 µM, respectively; specificly induces the degradation of Hsp90β-dependent client proteins (EGFR, HER2, CDK4, CDK6, CXCR4 etc.) in cells.

M3258 (M 3258) is a potent, reversible, highly selective and orally acitve LMP7 inhibitor with ceullar IC50 of 4.1 nM.M3258 does not inhibit other constitutive proteasome and immunoproteasome subunits (IC50>2.5 uM).M3258 demonstrated strong antitumor efficacy in multiple myeloma xenograft models.M3258 treatment led to a significant and prolonged suppression of tumor LMP7 activity and ubiquitinated protein turnover and the induction of apoptosis in multiple myeloma cells both in vitro and in vivo.M3258 showed superior antitumor efficacy in selected multiple myeloma and mantle cell lymphoma xenograft models compared with the approved nonselective proteasome inhibitors bortezomib and ixazomib.

ML307 is a potent, sub-micromolar (IC50=781 nM), first-in-class, small molecule inhibitor of Ubc13 enzyme activity, >128-fold selective against Caspase-3 and Bfl-1.

MT16-001 is a selective, covalent inhibitor of deubiquitinating enzyme UCHL1 with IC50 of 580 nM, no inhibitory effect against UCHL3 (IC50>30 uM).MT16-001 inhibits structurally unrelated DUB USP30 with similar potency.MT16-001 showed cytotoxicity in human embryonic kidney cells (HEK293) with EC50 of 730 nM, effectively engaged UCHL1 in cells with EC50 of 550 nM.MT16-001 showed excellent selectivity for UCHL1 across the UCH family: UCHL1, UCHL3, UCHL5 and BAP1.

MT16-205 (MT 16-205) is a potent, selective, covalent UCHL1 inhibitor with IC50 of 600 nM, no inhibition agianst UCHL3 (IC50>10 uM).MT16-205 inhibited both UCHL1 and the structurally unrelated DUB USP30 with similar potency.MT16-205 displayed cell proliferation cytotoxicity in human embryonic kidney cells (HEK293) with IC50 of 350 nM, MT16-205 effectively engaged UCHL1 in cells with IC50 of 830 nM.

MyoMed-946 is a small moelcule that inhibits MuRF1 (TRIM63) activity and MuRF1/MuRF2 expression; MyoMed-946 inhibits MuRF1 expression/activity in vivo and is able to attenuate skeletal muscle atrophy and dysfunction in mice treated with monocrotaline to induce right ventricular hypertrophy and subsequent cardiac cachexia. MyoMed-946 attenuates skeletal muscle strength loss in mouse model for type 2 diabetes mellitus (T2DM), with no significant effects on serum glucose. MyoMed-946 attenuates induction of MuRF1 in tumor stressed muscles. MyoMed-946 also rescues citrate synthase and complex-1 activities in tumor-stressed muscles. MuRF1 (muscle-specific RING finger protein-1) is a muscle-specific ubiquitin ligase that regulates muscle catabolism during chronic wasting states, both MuRF1 and MuRF2 participate in glucose and, also, in lipid regulation.

NJH-2-075 is an alkyne-functionalized probe of EN523, retains binding to OTUB1 in vitro.

NPX-800 is a potent, selective, oral heat shock factor 1 (HSF1) pathway inhibitor.

S1g-2 (Hsp70-Bim inhibitor S1g-2) is a selective inhibitor to block interactions of Hsp70-Bim with IC50 of 0.4 uM in FPA assays, > 40-fold selectivity to target Hsp70-Bim over Bcl-2-Bim. S1g-2 induces cell-type-specific apoptosis in CML cells through selectively disrupting the Hsp70-Bim PPI. S1g-2 progressively enhanced lethality along with the increase in BCR-ABL-independent TKI resistance in the K562 cell lines. S1g-2 is more effective in primary samples from BCR-ABL-independent TKI-resistant patients than those from TKI-sensitive patients.

SEW84 (SEW04784) is a first-in-class, specific inhibitor of the Aha1-stimulated Hsp90 (ASH) ATPase activity (IC50=0.3 uM) without inhibiting basal Hsp90 ATPase; SEW84 binds to the C-terminal domain of Aha1 (Kd=1.7 uM) to weaken its asymmetric binding to Hsp90. SEW84 inhibited the GR- and AR-dependent luciferase expression with IC50 of 1.3 uM and 0.7 uM respectively. SEW84 blocks Aha1-dependent Hsp90 chaperoning activities, including the in vitro and in vivo refolding of firefly luciferase, and the transcriptional activity of the androgen receptor in cell-based models of prostate cancer. SEW84 promotes the clearance of phosphorylated tau in cellular and tissue models of neurodegenerative tauopathy.

SU086 is an inhibitor of HSP90, binds to HSP90-alpha and HSP90-beta isoforms, decreases HSP90 protein levels in prostate cancer cells.SU086 is a potent inhibitor of prostate cancer cell growth, migration, and invasion in vitro, significantly inhibited growth of AR-positive CRPC cell lines (C4-2), AR-negative (DU145 and PC-3) CRPC cells, and CRPC cells with expression of AR and AR splice variant, AR-V7 (22Rv1) (IC50 <10 uM).SU086 inhibits prostate cancer growth in preclinical models of prostate cancer in vivo.SU086 strongly enhances the anti-tumor activity of standard of care second-generation anti-androgens enzalutamide and abiraterone and inhibits prostate cancer cell growth in vitro and tumor growth in vivo.