Proximity-dependent Mapping of the Androgen Receptor Identifies Kruppel-like Factor 4 as a Functional Partner

Lauriane Vélot,Frédéric Lessard,Félix-Antoine Bérubé-Simard,Christophe Tav,Bertrand Neveu,Valentine Teyssier,Imène Boudaoud,Ugo Dionne,Noémie Lavoie,Steve Bilodeau,Frédéric Pouliot,Nicolas Bisson

doi:10.1016/j.mcpro.2021.100064

Lauriane Vélot, Frédéric Lessard + Show 10 more

Open Access

https://doi.org/10.1016/j.mcpro.2021.100064

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Abstract

Prostate cancer (PCa) is the most frequently diagnosed cancer in men and the third cause of cancer mortality. PCa initiation and growth are driven by the androgen receptor (AR). The AR is activated by androgens such as testosterone and controls prostatic cell proliferation and survival. Here, we report an AR signaling network generated using BioID proximity labeling proteomics in androgen-dependent LAPC4 cells. We identified 31 AR-associated proteins in nonstimulated cells. Strikingly, the AR signaling network increased to 182 and 200 proteins, upon 24 h or 72 h of androgenic stimulation, respectively, for a total of 267 nonredundant AR-associated candidates. Among the latter group, we identified 213 proteins that were not previously reported in databases. Many of these new AR-associated proteins are involved in DNA metabolism, RNA processing, and RNA polymerase II transcription. Moreover, we identified 44 transcription factors, including the Kru¨ppel-like factor 4 (KLF4), which were found interacting in androgen-stimulated cells. Interestingly, KLF4 repressed the well-characterized AR-dependent transcription of the KLK3 (PSA) gene; AR and KLF4 also colocalized genome-wide. Taken together, our data report an expanded high-confidence proximity network for AR, which will be instrumental to further dissect the molecular mechanisms underlying androgen signaling in PCa cells.

Highlights

BioID proteomics identifies 267 androgen receptor (AR)-associated candidates Krüppel-like factor 4 (KLF4) is a new AR interaction partner AR and KLF4 colocalize genome-wide on >4000 genes, including KLK3 (PSA) KLF4 acts as a repressor for the AR target gene KLK3 (PSA)
We report a high-confidence proximity network for AR in prostate cells
Lampiäinen et al reported an AR proximity network comprised of 32 preys in human embryonic kidney 293 cells (HEK293) cells [20]

Summary

Graphical Abstract

In Brief A proximity interaction network for the androgen receptor (AR) was obtained from androgenresponsive prostate cancer cells. The AR signaling network increased to 182 and 200 proteins, upon 24 h or 72 h of androgenic stimulation, respectively, for a total of 267 nonredundant AR-associated candidates Among the latter group, we identified 213 proteins that were not previously reported in databases. Paltoglou et al took advantage of the RIME method (rapid immunoprecipitation MS of endogenous proteins) to identify 54 and 75 candidates with wild-type AR and the constitutively active ARv567es variant, respectively They identified the transcription factor Grainyhead-like 2 (GRHL2) and characterized its function as a coregulator of AR, both as an oncogenic enhancer of androgen signaling and as a suppressor of metastasis [13]. We show that KLF4 and AR colocalize genome-wide on a number of genes including PSA (KLK3) and surprisingly act as a repressor for the latter, without regulating the expression of AR itself

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