RNA splicing reprogramming to combat triple-negative breast cancer

Abstract

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited targeted treatment options. This thesis investigates RNA splicing as both a driver of TNBC progression and a potential therapeutic vulnerability. A high-throughput RNAi screen identified several splicing factors that regulate TNBC cell migration, with SRSF7 emerging as a key regulator of motility and metastatic colonization through broad effects on gene expression and alternative splicing. Mapping the SRSF7 interactome further identified EIF4A3 and RBM8A as functional partners supporting TNBC cell growth, migration, and RNA processing. The thesis also reviews how SR protein activity is controlled by phosphorylation and dephosphorylation through kinases and phosphatases. Pharmacological inhibition of CLK kinases using T-025 disrupted SR protein function, altered SRSF7 interactions and nuclear dynamics, and induced widespread splicing changes affecting cell-cycle and migration-related pathways. T-025 consequently reduced TNBC proliferation and migration. Together, these findings show that TNBC depends on tightly regulated RNA-splicing programs and support splicing-factor networks and their upstream regulatory kinases as promising therapeutic targets.