A high-throughput screen reveals SALL4-induced oxidative phosphorylation vulnerabilities in cancer

Transcription factors are important drivers of cancer but the development of therapeutics against these factors has had limited success. We developed a stringent high-throughput chemical genetic screening platform to identify compounds that target oncogene SALL4 dependency in liver cancer. The platform comprises SALL4 low- and high-expressing endogenous cell lines, and engineered SALL4-low isogenic lines overexpressing SALL4. We identified 4 oxidative phosphorylation (OXPHOS) inhibitors, from screening 21,575 natural product extracts, that selectively reduce SALL4-dependent cell viability. ATP synthase inhibitor Oligomycin suppresses SALL4-expressing cancer in culture and in vivo. When aberrantly overexpressed in cancer, SALL4 binds ~50% of OXPHOS and other mitochondrial genes, upregulating their expression. SALL4 upregulation also functionally increases OXPHOS. Our endogenous/isogenic transcription factor-screening platform reveals a therapeutically actionable OXPHOS vulnerability in SALL4-expressing cancer. RNA-seq was performed on SALL4 knockdown and SALL4 overexpression cell line models to identify alterations in gene expression.