Uncovering the effect of long non-coding RNAs on liquid-liquid phase separation of androgen receptor in prostate cancer

Androgen receptor (AR) is a transcription factor whose overactivation
is a primary driver of prostate cancer (PC). AR was reported 1) to
form nuclear foci at super-enhancers by liquid-liquid phase
separation (LLPS) and 2) to interact with several long non-coding
RNAs (lncRNAs). Although multiple lines of evidence support the
therapeutic relevance of AR-lncRNA interactions, the underlying
molecular mechanisms and the role of lncRNAs in PC remain to be
elucidated. We plan to determine the binding site(s) of lncRNAs
within the disordered N-terminal domain (NTD) of AR and the ARbinding regions of 3 selected lncRNAs through hydrogen/deuterium
exchange mass spectrometry. Also, a powerful combination of in vitro
binding assays, biophysical experiments, cell-free transcriptional
assays, and cell-based assays will be used to determine the effect of
lncRNA binding on the LLPS and transcriptional activity of full-length
AR and of the AR-V7 isoform that displays ligand-independent
transcriptional activity critical in castration-resistant PC (CRPC). Also,
the effects of length variations in a polymorphic poly-Q stretch of the
AR NTD (the length of which inversely correlates with AR activation
and the risk of PC) on AR-lncRNA interactions and LLPS will also be
elucidated. By uncovering the interaction mechanisms and regulatory
roles of lncRNAs in the ligand-(in)dependent activation of AR, this
project will lay down the foundations for effective novel therapeutics
against PC and CRPC.