Targeting acute myeloid leukemia dependency on VCP-mediated DNA repair through a selective second-generation small-molecule inhibitor

Abstract

The development and survival of cancer cells require adaptive mechanisms to stress. Such adaptations can confer intrinsic vulnerabilities, enabling the selective targeting of cancer cells. Through a pooled in vivo short hairpin RNA (shRNA) screen, we identified the adenosine triphosphatase associated with diverse cellular activities (AAA-ATPase) valosin-containing protein (VCP) as a top stress-related vulnerability in acute myeloid leukemia (AML). We established that AML was the most responsive disease to chemical inhibition of VCP across a panel of 16 cancer types. The sensitivity to VCP inhibition of human AML cell lines, primary patient samples, and syngeneic and xenograft mouse models of AML was validated using VCP-directed shRNAs, overexpression of a dominant-negative VCP mutant, and chemical inhibition. By combining mass spectrometry–based analysis of the VCP interactome and phospho-signaling studies, we determined that VCP is important for ataxia telangiectasia mutated (ATM) kinase activation and subsequent DNA repair through homologous recombination in AML. A second-generation VCP inhibitor, CB-5339, was then developed and characterized. Efficacy and safety of CB-5339 were validated in multiple AML models, including syngeneic and patient-derived xenograft murine models. We further demonstrated that combining DNA-damaging agents, such as anthracyclines, with CB-5339 treatment synergizes to impair leukemic growth in an MLL-AF9–driven AML murine model. These studies support the clinical testing of CB-5339 as a single agent or in combination with standard-of-care DNA-damaging chemotherapy for the treatment of AML.

Valosin-Containing Protein (VCP)/p97: A Prognostic Biomarker and Therapeutic Target in Cancer

“…In 2021, a second-generation CB-5083 inhibitor, CB-5339, was developed and validated in multiple AML models, such as syngeneic and patient-derived xenograft murine models. The combination of CB-5339 with a DNA-damaging agent exerted a synergistic effect on an MLL-AF9-driven AML murine model [ 143 ].…”

AAA+ ATPase p97/VCP mutants and inhibitor binding disrupt inter-domain coupling and subsequent allosteric activation

“…Due to the essential role played by p97 in cellular processes, it is no surprise that a number of multisystem diseases are associated with mutations and dysfunctions in p97. Diseases arising from protein degradation defects ( 7 ) and DNA repair ( 8 ) such as cancer, viral infections such as the poliovirus ( 9 ), and even neurodegenerative disorders all implicate p97 as crucial in disease progression. p97 is therefore an attractive therapeutic target ( 10 ).…”

Phospho-Ser784-VCP Drives Resistance of Pancreatic Ductal Adenocarcinoma to Genotoxic Chemotherapies and Predicts the Chemo-Sensitizing Effect of VCP Inhibitor

“…Excitingly, a highly potent and selective ATP-competitive VCP inhibitor named CB-5339 is currently being evaluated in phase I clinical trials for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) and is anticipated to enter clinical testing for solid tumors as well. Most recently, it was reported that CB-5339 is highly effective at inhibiting in vitro and in vivo growth and survival of AML cell lines and mouse xenograft models as monotherapy [64]. Interestingly, the authors also showed that CB-5339 synergizes with standard chemotherapies consisting of genotoxic anthracycline and cytarabine, supporting the general idea that VCP inhibition can be chemo-sensitizing.…”

“…Interestingly, the authors also showed that CB-5339 synergizes with standard chemotherapies consisting of genotoxic anthracycline and cytarabine, supporting the general idea that VCP inhibition can be chemo-sensitizing. Not surprisingly, neither total VCP nor phospho-ATM and γH2AX levels correlate with the anticancer effects of CB-5339 [64]. Genetic profiling revealed an association between co-occurrence of RAS oncogenic activation and TP53 deficiency in AML cell lines and reduced the sensitivity to VCP inhibition.…”