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Updated: Aug 14, 2025

Measuring In Vitro ATPase Activity for Enzymatic Characterization
Published on: August 23, 2016
Inhibitors of the ATPase p97/VCP: From basic research to clinical applications
Susan Kilgas1, Kristijan Ramadan1
1Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
Abstract:
Protein homeostasis deficiencies underlie various cancers and neurodegenerative diseases. The ubiquitin-proteasome system (UPS) and autophagy are responsible for most of the protein degradation in mammalian cells and, therefore, represent attractive targets for cancer therapy and that of neurodegenerative diseases. The ATPase p97, also known as VCP, is a central component of the UPS that extracts and disassembles its substrates from various cellular locations and also regulates different steps in autophagy. Several UPS- and autophagy-targeting drugs are in clinical trials. In this review, we focus on the development of various p97 inhibitors, including the ATPase inhibitors CB-5083 and CB-5339, which reached clinical trials by demonstrating effective anti-tumor activity across various tumor models, providing an effective alternative to targeting protein degradation for cancer therapy. Here, we provide an overview of how different p97 inhibitors have evolved over time both as basic research tools and effective UPS-targeting cancer therapies in the clinic.
Insights
Protein degradation pathways, including the ubiquitin-proteasome system (UPS) and autophagy, are crucial for cellular health. Inhibitors targeting the ATPase p97 (VCP) show promise as cancer therapies by disrupting these pathways.
Area of Science:
- Molecular Biology
- Cellular Biology
- Biochemistry
Background:
- Protein homeostasis is vital, with deficiencies linked to cancer and neurodegenerative diseases.
- The ubiquitin-proteasome system (UPS) and autophagy are key protein degradation pathways.
- The ATPase p97 (VCP) is a central regulator of both UPS and autophagy.
Purpose of the Study:
- To review the development of p97 inhibitors.
- To highlight their evolution as research tools and therapeutic agents.
- To discuss their potential in cancer therapy.
Main Methods:
- Review of existing literature on p97 inhibitors.
- Analysis of clinical trial data for compounds like CB-5083 and CB-5339.
- Examination of p97's role in protein degradation and autophagy.
Main Results:
- p97 inhibitors, such as CB-5083 and CB-5339, have demonstrated significant anti-tumor activity.
- These inhibitors are progressing through clinical trials.
- p97 inhibition offers a novel strategy for targeting protein degradation in cancer.
Conclusions:
- p97 inhibitors represent a promising therapeutic avenue for cancer.
- Their development signifies progress in targeting protein degradation pathways.
- Further research into p97 inhibitors could yield effective treatments for various diseases.
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