Antitumorigenic potential of STAT3 alternative splicing modulation

作者：Zammarchi Francesca; de Stanchina Elisa; Bournazou Eirini; Supakorndej Teerawit; Martires Kathryn; Riedel Elyn; Corben Adriana D; Bromberg Jacqueline F; Cartegni Luca^*

来源：Proceedings of the National Academy of Sciences, 2011, 108(43): 17779-17784.

DOI：10.1073/pnas.1108482108

Signal transducer and activator of transcription 3 (STAT3) plays a central role in the activation of multiple oncogenic pathways. Splicing variant STAT3 beta uses an alternative acceptor site within exon 23 that leads to a truncated isoform lacking the C-terminal transactivation domain. Depending on the context, STAT3 beta can act as a dominant-negative regulator of transcription and promote apoptosis. We show that modified antisense oligonucleotides targeted to a splicing enhancer that regulates STAT3 exon 23 alternative splicing specifically promote a shift of expression from STAT3 alpha to STAT3 beta. Induction of endogenous STAT3 beta leads to apoptosis and cell-cycle arrest in cell lines with persistent STAT3 tyrosine phosphorylation compared with total STAT3 knockdown obtained by forced splicing-dependent nonsense-mediated decay (FSD-NMD). Comparison of the molecular effects of splicing redirection to STAT3 knockdown reveals a unique STAT3 beta signature, with a down-regulation of specific targets (including lens epithelium-derived growth factor, p300/CBP-associated factor, CyclinC, peroxisomal biogenesis factor 1, and STAT1 beta) distinct from canonical STAT3 targets typically associated with total STAT3 knockdown. Furthermore, similar in vivo redirection of STAT3 alternative splicing leads to tumor regression in a xenograft cancer model, demonstrating how pharmacological manipulation of a single key splicing event can manifest powerful antitumorigenic properties and validating endogenous splicing reprogramming as an effective cancer therapeutic approach.

• 出版日期2011-10-25