A high-throughput approach to identify BRCA1-downregulating compounds to enhance PARP inhibitor sensitivity

Erin Sellars; Margarita Savguira; Jie Wu; Sabrina Cancelliere; Mark Jen; Rehna Krishnan; Anne Hakem; Dalia Barsyte-Lovejoy; Razqallah Hakem; Steven A. Narod; Joanne Kotsopoulos; Leonardo Salmena

iScience (Jul 2024)

A high-throughput approach to identify BRCA1-downregulating compounds to enhance PARP inhibitor sensitivity

Erin Sellars,
Margarita Savguira,
Jie Wu,
Sabrina Cancelliere,
Mark Jen,
Rehna Krishnan,
Anne Hakem,
Dalia Barsyte-Lovejoy,
Razqallah Hakem,
Steven A. Narod,
Joanne Kotsopoulos,
Leonardo Salmena

Affiliations

Erin Sellars: Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada; Women’s College Research Institute, Women’s College Hospital, Toronto, ON M5S 1B2, Canada
Margarita Savguira: Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
Jie Wu: Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
Sabrina Cancelliere: Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
Mark Jen: Lunenfeld-Tanenbaum Research Institute, Network Biology Collaborative Centre, High-Throughput Screening, Mt. Sinai Hospital, Sinai Health System, Toronto, ON M5G 1X5, Canada
Rehna Krishnan: Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
Anne Hakem: Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
Dalia Barsyte-Lovejoy: Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada; Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
Razqallah Hakem: Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
Steven A. Narod: Women’s College Research Institute, Women’s College Hospital, Toronto, ON M5S 1B2, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON M5T 3M7, Canada
Joanne Kotsopoulos: Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada; Women’s College Research Institute, Women’s College Hospital, Toronto, ON M5S 1B2, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON M5T 3M7, Canada
Leonardo Salmena: Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada; Women’s College Research Institute, Women’s College Hospital, Toronto, ON M5S 1B2, Canada; Corresponding author

Journal volume & issue: Vol. 27, no. 7
p. 110180

Abstract

Read online

Summary: PARP inhibitors (PARPi) are efficacious in BRCA1-null tumors; however, their utility is limited in tumors with functional BRCA1. We hypothesized that pharmacologically reducing BRCA1 protein levels could enhance PARPi effectiveness in BRCA1 wild-type tumors. To identify BRCA1 downregulating agents, we generated reporter cell lines using CRISPR-mediated editing to tag endogenous BRCA1 protein with HiBiT. These reporter lines enable the sensitive measurement of BRCA1 protein levels by luminescence. Validated reporter cells were used in a pilot screen of epigenetic-modifying probes and a larger screen of more than 6,000 compounds. We identified 7 compounds that could downregulate BRCA1-HiBiT expression and synergize with olaparib. Three compounds, N-acetyl-N-acetoxy chlorobenzenesulfonamide (NANAC), A-443654, and CHIR-124, were validated to reduce BRCA1 protein levels and sensitize breast cancer cells to the toxic effects of olaparib. These results suggest that BRCA1-HiBiT reporter cells hold promise in developing agents to improve the clinical utility of PARPi.

Published in iScience

ISSN: 2589-0042 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Science
Website: http://www.cell.com/iscience/home

About the journal

Abstract

Keywords