title: Transfected poly(I:C) activates different dsRNA receptors, leading to apoptosis or immunoadjuvant response in androgen-independent prostate cancer cells.
abstract: Despite the effectiveness of surgery or radiation therapy for the treatment of early-stage prostate cancer (PCa), there is currently no effective strategy for late-stage disease. New therapeutic targets are emerging; in particular, dsRNA receptors Toll-like receptor 3 (TLR3) and cytosolic helicases expressed by cancer cells, once activated, exert a pro-apoptotic effect in different tumors. We previously demonstrated that the synthetic analog of dsRNA poly(I:C) induces apoptosis in the androgen-dependent PCa cell line LNCaP in a TLR3-dependent fashion, whereas only a weak apoptotic effect is observed in the more aggressive and androgen-independent PCa cells PC3 and DU145. In this paper, we characterize the receptors and the signaling pathways involved in the remarkable apoptosis induced by poly(I:C) transfected by Lipofectamine (in-poly(I:C)) compared with the 12-fold higher free poly(I:C) concentration in PC3 and DU145 cells. By using genetic inhibition of different poly(I:C) receptors, we demonstrate the crucial role of TLR3 and Src in in-poly(I:C)-induced apoptosis. Therefore, we show that the increased in-poly(I:C) apoptotic efficacy is due to a higher binding of endosomal TLR3. On the other hand, we show that in-poly(I:C) binding to cytosolic receptors MDA5 and RIG-I triggers IRF3-mediated signaling, leading uniquely to the up-regulation of IFN-β, which likely in turn induces increased TLR3, MDA5, and RIG-I proteins. In summary, in-poly(I:C) activates two distinct antitumor pathways in PC3 and DU145 cells: one mediated by the TLR3/Src/STAT1 axis, leading to apoptosis, and the other one mediated by MDA5/RIG-I/IRF3, leading to immunoadjuvant IFN-β expression.
authors.affiliation: From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Anatomy, Histology, Forensic Medicine, and Orthopedics, Section of Histology and Medical Embryology, "Sapienza" University of Rome, Rome, Italy and.
authors.forename: Sara
authors.initials: S
authors.lastname: Palchetti
authors.affiliation: From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Anatomy, Histology, Forensic Medicine, and Orthopedics, Section of Histology and Medical Embryology, "Sapienza" University of Rome, Rome, Italy and donatella.starace@uniroma1.it.
authors.forename: Donatella
authors.initials: D
authors.lastname: Starace
authors.affiliation: the Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: De Cesaris
authors.affiliation: From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Anatomy, Histology, Forensic Medicine, and Orthopedics, Section of Histology and Medical Embryology, "Sapienza" University of Rome, Rome, Italy and.
authors.forename: Antonio
authors.initials: A
authors.lastname: Filippini
authors.affiliation: From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Anatomy, Histology, Forensic Medicine, and Orthopedics, Section of Histology and Medical Embryology, "Sapienza" University of Rome, Rome, Italy and.
authors.forename: Elio
authors.initials: E
authors.lastname: Ziparo
authors.affiliation: From the Istituto Pasteur-Fondazione Cenci Bolognetti, Department of Anatomy, Histology, Forensic Medicine, and Orthopedics, Section of Histology and Medical Embryology, "Sapienza" University of Rome, Rome, Italy and anna.riccioli@uniroma1.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Riccioli
mesh_terms: D000276:Adjuvants, Immunologic / Q000378:metabolism; D000728:Androgens / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000235:genetics / Q000378:metabolism; D000072640:Interferon-Induced Helicase, IFIH1; D016899:Interferon-beta / Q000235:genetics / Q000378:metabolism; D008297:Male; D018613:Microscopy, Confocal; D011070:Poly I-C / Q000235:genetics* / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D051196:Toll-Like Receptor 3 / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
chemical_list: D000276:Adjuvants, Immunologic; D000728:Androgens; C494232:IRF3 protein, human; D050838:Interferon Regulatory Factor-3; D011956:Receptors, Cell Surface; D050794:STAT1 Transcription Factor; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; C045250:poly I-C receptor; D016899:Interferon-beta; C522809:RNF135 protein, human; D044767:Ubiquitin-Protein Ligases; D016392:Proto-Oncogene Proteins pp60(c-src); C452815:IFIH1 protein, human; D053487:DEAD-box RNA Helicases; D000072640:Interferon-Induced Helicase, IFIH1; D011070:Poly I-C
keywords: Double-stranded RNA (dsRNA); Endosome; Innate Immunity; Prostate Cancer; Signal Transduction; Toll-like Receptor (TLR)