Androgen Signalling Laboratory, Department of Surgery and Cancer, Imperial College London. Hammersmith Hospital Campus, Division of Cell and Molecular Biology, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, Experimental Histopathology Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields, Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, and Department of Histopathology, Imperial College London, St Mary's Campus, Norfolk Place, London, United Kingdom; andNorthern Institute for Cancer Research, Newcastle University, Newcastle Upon Tyne, United Kingdom.
Progression of prostate cancer is highly dependent upon the androgen receptor pathway, such that knowledge of androgen-regulated proteins is vital to understand and combat this disease. Using a proteomic screen, we found the RNA-binding protein FUS/TLS (Fused in Ewing's Sarcoma/Translocated in Liposarcoma) to be downregulated in response to androgen. FUS has recently been shown to be recruited by noncoding RNAs to the regulatory regions of target genes such as cyclin D1, in which it represses transcription by disrupting complex formation. Here we show that FUS has some characteristics of a putative tumor suppressor, as its overexpression promoted growth inhibition and apoptosis of prostate cancer cells, whereas its knockdown increased cell proliferation. This effect was reproducible in vivo, such that increasing FUS levels in tumor xenografts led to dramatic tumor regression. Furthermore, FUS promoted conditions that favored cell-cycle arrest by reducing the levels of proliferative factors such as cyclin D1 and Cdk6 and by increasing levels of the antiproliferative Cdk inhibitor p27. Immunohistochemical analysis revealed that FUS expression is inversely correlated with Gleason grade, demonstrating that patients with high levels of FUS survived longer and were less likely to have bone metastases, suggesting that loss of FUS expression may contribute to cancer progression. Taken together, our results address the question of how androgens regulate cell-cycle progression, by demonstrating that FUS is a key link between androgen receptor signaling and cell-cycle progression in prostate cancer.
Written by:
Brooke GN, Culley RL, Dart DA, Mann DJ, Gaughan L, McCracken SR, Robson CN, Spencer-Dene B, Gamble SC, Powell SM, Wait R, Waxman J, Walker MM, Bevan CL.
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Reference: Cancer Res. 2011 Jan 25. Epub ahead of print.
doi: 10.1158/0008-5472.CAN-10-0874
PubMed Abstract
PMID: 21169411
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