CB-5083

To overcome these barriers, a pH-responsive solid lipid nanoparticle (SLN) system was engineered to co-deliver CB-5083 (a VCP/p97 inhibitor), miR-142 (a PD-L1-targeting microRNA), and imiquimod (R, a TLR7 agonist) for spatially confined induction of endoplasmic reticulum stress (ERS) and immune reprogramming in MSS CRC. Biodistribution analysis confirmed tumor-preferential accumulation with minimal off-target exposure, and biosafety profiling demonstrated low systemic toxicity. This TME-responsive nanoplatform therefore integrates ERS induction, checkpoint modulation, and cytokine suppression to overcome immune exclusion in MSS CRC, representing a clinically translatable strategy for chemo-immunotherapy in immune-refractory tumors.

Our study identifies VCP as a new regulator of STING proteostasis and provides a novel strategy to boost antitumor immunity by pharmacologically increasing ER-resident STING via VCP inhibition, offering a clinically actionable avenue to improve CRC therapy.

Here, we highlight the optimization of the previously reported 3-thioalkyl-1,2,4-triazol-pyridyl allosteric inhibitor scaffold and identify two compounds (25 and 38) with low-nanomolar biochemical potency, submicromolar cellular inhibition, in vivo effects on biomarkers of VCP inhibition, and antitumor efficacy in mouse xenograft tumor models. Furthermore, compound 38 demonstrated robust inhibition of VCP ATP-site mutant proteins and growth of cells resistant to the known ATP-competitive inhibitor CB-5083.

Using data from the PRISM Repurposing drug sensitivity database, we observed that among compounds related to protein homeostasis, the valosin-containing protein (VCP) inhibitor CB-5083 demonstrated the most significant variation in sensitivity among NSCLC cells, categorized according to FAT1 expression levels...Our results suggest that FAT1 regulates the activation of the ER stress pathway through YAP signaling, influencing the susceptibility of NSCLC cells to VCP inhibitors. These insights provide novel perspectives for NSCLC treatment and extend the therapeutic applications of VCP inhibitors in clinical settings.

Our data suggest that combined treatment with CB-5083 and Lut might be applied to treat BC.

Footprinting analysis identified transcription factors implied in modulating chromatin accessibility in response to CB-6644 treatment, including ATF4/CEBP and IRF4. Lastly, integrative analysis of transcription responses to various chemical compounds of the molecular signature genes from public gene expression data identified CB-5083, a p97 inhibitor, as a synergistic candidate with CB-6644 in MM cells, but experimental validation refuted this hypothesis.

In this innovative preclinical investigation, the VCP/p97 inhibitor CB-5083 (CB), miR-142, a PD-L1 inhibitor, and immunoadjuvant resiquimod (R848; R) were synergistically encapsulated in solid lipid nanoparticles (SLNs)...This versatile nanoformulation allows tailored adjustment of the tumor microenvironment, thereby optimizing the localized delivery of combined therapy. These compelling findings advocate the potential development of a pH-sensitive, three-in-one PGA-PEG nanoformulation that combines a VCP inhibitor, a PD-L1 inhibitor, and an immunoadjuvant for cancer treatment via combinatorial chemo-immunotherapy.

CB-5083, a novel valosin-containing protein (VCP)/p97 inhibitor that disrupts proteasomal degradation and induces endoplasmic reticulum stress (ERS) accumulation, was evaluated as an inducer of immunogenic cell death (ICD) in PDAC treatment...Combined treatment blocked VCP, arrested the cell cycle, inhibited EMT, triggered ERS-mediated autophagy/apoptosis, and stimulated robust ICD via the release of damage-associated molecular patterns. This adaptable nanoformulation, displaying pH-sensitive PEG-PGA de-coating and precisely targeting EGFR, PD-L1, and ER, serves to hinder EMT and immune evasion, subsequently amplifying ICD in PDAC cells and the TME.

Notably, pharmacological inhibition of VCP by CB-5083 or knockdown of DERL1 partially abolishes the oncogenic effects of TMEM63A on TNBC progression both in vitro and in vivo. Collectively, these findings uncover a previously unknown functional and mechanistic role for TMEM63A in TNBC progression and provide a new clue for targeting TMEM63A-driven TNBC tumors by using a VCP inhibitor.Abbreviations: ATG16L1, autophagy related 16 like 1; ATG5, autophagy related 5; ATP5F1B/ATP5B, ATP synthase F1 subunit beta; Baf-A1, bafilomycin A; CALCOCO2/NDP52, calcium binding and coiled-coil domain 2; CANX, calnexin; DERL1, derlin 1; EGFR, epidermal growth factor receptor; ER, endoplasmic reticulum; ERAD, endoplasmic reticulum-associated degradation; HSPA8, heat shock protein family A (Hsp70) member 8; IP, immunoprecipitation; LAMP2A, lysosomal associated membrane protein 2; NBR1, NBR1 autophagy cargo receptor; OPTN, optineurin; RT-qPCR, reverse transcription-quantitative PCR; SQSTM1/p62, sequestosome 1; TAX1BP1, Tax1 binding protein 1; TMEM63A, transmembrane protein 63A; TNBC, triple-negative breast cancer; TOLLIP, toll interacting protein; VCP, valosin containing protein.

Here, we show that VCP inhibitors induce cytotoxicity in several ovarian cancer cell lines and these compounds act synergistically with mifepristone, a drug previously shown to induce an atypical unfolded protein response. In contrast, CB-5083 activates ATF4 and CHOP through the PERK (EIF2AK3)-mediated signaling pathway. This combination activates ATF4 and CHOP while blocking the adaptive response provided by ATF6, resulting in increased cytotoxic effects and synergistic drug interaction.

Western blot analysis validated the degradation of cyclin D1 and Securin, which depends on proteasome but not on p97. Differing regulation of cell cycle proteins by p97 and the proteasome may, therefore, explain the therapeutic efficacy of p97 inhibitors in colon cancer.