title: Targeting JNK-interacting-protein-1 (JIP1) sensitises osteosarcoma to doxorubicin.
abstract: Osteosarcoma (OS) is the most common primary malignant bone tumour in children and adolescents. Despite aggressive therapy, survival outcomes remain unsatisfactory, especially for patients with metastatic disease or patients with a poor chemotherapy response. Chemoresistance contributes to treatment failure. To increase the efficacy of conventional chemotherapy, essential survival pathways should be targeted concomitantly. Here, we performed a loss-of-function siRNA screen of the human kinome in SaOS-2 cells to identify critical survival kinases after doxorubicin treatment. Gene silencing of JNK-interacting-protein-1 (JIP1) elicited the most potent sensitisation to doxorubicin. This candidate was further explored as potential target for chemosensitisation in OS. A panel of OS cell lines and human primary osteoblasts was examined for sensitisation to doxorubicin using small molecule JIP1-inhibitor BI-78D3. JIP1 expression and JIP1-inhibitor effects on JNK-signalling were investigated by Western blot analysis. JIP1 expression in human OS tumours was assessed by immunohistochemistry on tissue micro arrays. BI-78D3 blocked JNK-signalling and sensitised three out of four tested OS cell lines, but not healthy osteoblasts, to treatment with doxorubicin. Combination treatment increased the induction of apoptosis. JIP1 was found to be expressed in two-thirds of human primary OS tissue samples. Patients with JIP1 positive tumours showed a trend to inferior overall survival. Collectively, JIP1 appears a clinically relevant novel target in OS to enhance the efficacy of doxorubicin treatment by means of RNA interference or pharmacological inhibition.
authors.affiliation: Department of Orthopaedic Surgery, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Jantine
authors.initials: J
authors.lastname: Posthumadeboer
authors.forename: Pim W
authors.initials: PW
authors.lastname: van Egmond
authors.forename: Marco N
authors.initials: MN
authors.lastname: Helder
authors.forename: Renée X
authors.initials: RX
authors.lastname: de Menezes
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Cleton-Jansen
authors.forename: Jeroen A M
authors.initials: JA
authors.lastname: Beliën
authors.forename: Henk M W
authors.initials: HM
authors.lastname: Verheul
authors.forename: Barend J
authors.initials: BJ
authors.lastname: van Royen
authors.forename: Gert-Jan J L
authors.initials: GJ
authors.lastname: Kaspers
authors.forename: Victor W
authors.initials: VW
authors.lastname: van Beusechem
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000293:Adolescent; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D009367:Neoplasm Staging; D010006:Osteoblasts / Q000378:metabolism / Q000473:pathology; D012516:Osteosarcoma / Q000188:drug therapy* / Q000235:genetics / Q000401:mortality; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D046888:Tissue Array Analysis
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000903:Antibiotics, Antineoplastic; C490666:MAPK8IP1 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D004317:Doxorubicin