# Preclinical characterization of EMT/CSC-specific small molecule inhibitors for TNBCs

> **NIH NIH R01** · UNIVERSITY OF TX MD ANDERSON CAN CTR · 2020 · $535,276

## Abstract

Triple negative (ER-, PR-, HER2-) breast cancers (TNBCs) lack targeted treatments, resulting in a high
mortality rate. Recurrence of chemotherapy-resistant tumors as well as formation of distant metastases are
both contributors to mortality within the first 3-5 years. We and others have shown that TNBCs are enriched
with cancer stem-cell (CSC)- and mesenchymal features, and that the induction of an epithelial-mesenchymal-
transition (EMT) promotes the de novo generation/expansion of drug-resistant CSCs. Indeed, the gene
expression signature generated by induction of EMT is enriched in claudin-low breast cancers, a particular
intrinsic subtype comprising nearly half of all TNBCs.
We recently reported that expression of the forkhead-box transcription factor FOXC2 is uniquely induced
following EMT and in CSCs, and that FOXC2 is sufficient for EMT, tumor initiation, and metastasis of TNBC
cell lines and chemotherapy-resistance. Remarkably, shRNA-mediated knockdown of FOXC2 is sufficient to
block induction of EMT, metastasis as well as the CSC-associated properties of tumor initiation and
chemotherapy-resistance. Given these results, we reasoned that a drug discovery screen for small molecules
that selectively target FOXC2-expressing CSCs will yield important chemical agents that will dramatically
improve treatment of CSC-enriched TNBCs.
We have performed a high-throughput small molecule screen of approximately 100,000 agents, and have
identified seven candidate molecules with preferential activity against FOXC2-expressing CSCs. In this
proposal, we intend to fully characterize and validate the in vitro activity of these molecules across a wide
spectrum of breast cancer cell lines for their selectivity for CSCs, their ability to block induction and reverse
EMT-associated tumor cell properties (including migration and invasion), and their capacity to alter CSC traits
(including mammosphere formation, marker expression and colony formation). In addition, we will elucidate the
relevant protein targets for these agents, by use of photo-affinity reagents followed by mass spectrometry, and
also determine the functional role of these target proteins for EMT/CSC properties. Finally, we will optimize
candidate molecules for in vivo delivery and acceptable pharmacokinetics, and conduct extensive preclinical
testing in mice using multiple TNBC patient-derived xenografts.
The results of this study will directly permit the identification of novel drugs for treating recurrent and metastatic
TNBCs, and will also shed light on the molecular networks regulated by FOXC2 during its reprogramming of
tumor cells towards the CSC/metastatic state. The strong collaboration between Dr. Mani and Dr. Lairson,
evidenced by our extensive preliminary data, indicates a high likelihood of success. Furthermore, the extended
scope of this proposal, from drug discovery using high-throughput screens, to testing in patient-derived TNBC
xenografts, indicates our commitment to rapidly movi...

## Key facts

- **NIH application ID:** 9898158
- **Project number:** 5R01CA200970-04
- **Recipient organization:** UNIVERSITY OF TX MD ANDERSON CAN CTR
- **Principal Investigator:** Luke Lee Lairson
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $535,276
- **Award type:** 5
- **Project period:** 2017-04-01 → 2022-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9898158

## Citation

> US National Institutes of Health, RePORTER application 9898158, Preclinical characterization of EMT/CSC-specific small molecule inhibitors for TNBCs (5R01CA200970-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9898158. Licensed CC0.

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