Epidermal growth factor receptor (EGFR) plays a central role in the progression of several human malignancies. Although EGFR is a membrane receptor, it undergoes nuclear translocation, where it has a distinct signalling pathway. Herein, we report a novel mechanism by which cancer cells can directly transport EGFR to the nucleus of other cells via extracellular vesicles (EVs). The transported receptor is active and stimulates the nuclear EGFR pathways. Interestingly, the translocation of EGFR via EVs occurs independently of the nuclear localisation sequence that is required for nuclear translocation of endogenous EGFR. Also, we found that the mutant receptor EGFRvIII could be transported to the nucleus of other cells via EVs. To assess the role of EVs in the regulation of an actual nuclear receptor, we studied the regulation of androgen receptor (AR). We found that full-length AR and mutant variant ARv7 are secreted in EVs derived from prostate cancer cell lines and could be transported to the nucleus of AR-null cells. The EV-derived AR was able to bind the androgen-responsive promoter region of prostate specific antigen, and recruit RNA Pol II, an indication of active transcription. The nuclear-translocated AR via EVs enhanced the proliferation of acceptor cells in the absence of androgen. Finally, we provide evidence that nuclear localisation of AR could occur in vivo via orthotopically-injected EVs in male SCID mice prostate glands. To our knowledge, this is the first study showing the nuclear translocation of nuclear receptors via EVs, which significantly extends the role of EVs as paracrine transcriptional regulators.
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European journal of cancer (Oxford, England : 1990). 2016 Jan 22 [Epub ahead of print]
Jolene Read, Alistair Ingram, Hassan A Al Saleh, Khrystyna Platko, Kathleen Gabriel, Anil Kapoor, Jehonathan Pinthus, Fadwa Majeed, Talha Qureshi, Khalid Al-Nedawi
Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada., Medical School, University of Ottawa, Ottawa, Canada., Division of Urology, Department of Surgery, McMaster University, Canada., Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Canada., Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Canada. Electronic address: .