# Generation of highly selective activity based probes using chemically modified phage

> **NIH NIH R01** · STANFORD UNIVERSITY · 2020 · $354,257

## Abstract

Project Summary
Proteases represent one of the largest and most well characterized families of enzymes in the human genome.
Furthermore, there are many human health conditions such as cancer that are associated with alterations in
protease activity and function. Therefore, specific molecular probes that allow individual protease activities to
be imaged during disease progression in vivo would both be transformative in our understanding of the roles of
proteolytic events that contribute to disease pathology while also providing a direct methods for early disease
monitoring and response to therapy. The past decade has produced many diverse classes of molecular probes
that can be used for imaging applications. Perhaps one of the most powerful of these reagents is the activity
based probe (ABP). However the broad application of ABPs is typically limited by the need to painstakingly
optimize probes using synthetic chemistry and often probes lack absolute specificity for a given target enzyme.
This proposal will focus on establishing an innovative technology that will allow rapid design of ABPs with
exceptional specificity for any given protease target of interest. This will involve application of a phage display
method to screen diverse libraries of chemically constrained bi-cyclic peptides linked to a protease reactive
electrophile to iteratively screen for covalent binding elements with high potency and selectivity. We propose to
establish and validate the phage screening method using two stromal-cell derived protease targets, cathepsin
S (cat S) and fibroblast activation protein (FAP), involved in key aspects of tumorigenesis. These new probes
will then be validated for imaging applications in mouse models of cancer. The technology developed in this
proposal will result in not only a new general method for protease ABP development but also will produce
probes with potential future clinical applications in cancer imaging.

## Key facts

- **NIH application ID:** 9850972
- **Project number:** 5R01EB026285-03
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** Matthew Bogyo
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $354,257
- **Award type:** 5
- **Project period:** 2018-05-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9850972

## Citation

> US National Institutes of Health, RePORTER application 9850972, Generation of highly selective activity based probes using chemically modified phage (5R01EB026285-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9850972. Licensed CC0.

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