Development of p97 Inhibitors as a Potential Cancer Therapy

The primary area of our research focuses on the enzyme p97, also known as the Transitional Endoplasmic Reticulum ATPase (TER). p97/TER is a homo-hexamer consisting of two catalytic domains, and it uses the energy derived from ATP-hydrolysis to carry out several different cellular functions. It coordinates these functions through association with a myriad of cofactor/adapter proteins (see below).

(Chapman et al., 2015)

We are employing a combination of chemical biology, quantitative proteomics, high-throughput, high-content screenings, and biochemical reconstitution to study the mechanism by which p97 orchestrates two major protein clearance pathways, proteasome and autophagy, as well as how it regulates the activity of proteins involved in apoptosis. These processes are especially vital in cancer cells due to an increased reliance on protein clearance of mis-folded proteins, making p97 an attractive cancer target.

In fact, in just the past year, a new p97 inhibitor developed by Cleave Biosciences has begun clinical trials for Multiple Myeloma.

Using Proteomics to Identify New Biomarkers

We are using our novel p97 inhibitors in combination with genetic inhibition by RNAi or a dominant negative p97 mutant in proteomic experiments utilizing mass spectrometry to identify novel substrates and investigate the biological functions of p97. As a whole, this work will generate important biomarkers for evaluating the pharmacodynamics of the anti-cancer effects of p97 inhibitors in future animal studies and will facilitate the development of novel and targeted therapeutic agents.

Developing Complex-Specific Inhibitors

Through site directed mutagenesis, we are uncovering the structural basis for protein-protein interactions, and since p97 acts through a wide array of cofactors and adapter proteins, we are also interested in the effect of cofactor-binding on enzyme kinetics and inhibitor potency. These studies will enable us to identify and develop more potent p97-cofactor specific inhibitors that will yield a higher therapeutic index due to decreased off-target effects.

Structural Characterization of p97 in Golgi membrane Reassembly

We are interested in the interaction of p97, its cofactors, and adaptor proteins in mediating golgi reassembly after mitosis. We use novel purification methods to yield proteins of interest which will be utilize for downstream assays. This study will give light to our understanding on how p97/p47/vcip135 complex facilitate golgi reassembly biochemically and structurally.

Huang et al. Dev Cell. 2016. doi:10.1016/j.devcel.2016.06.001