title: CRM1 Inhibition Promotes Cytotoxicity in Ewing Sarcoma Cells by Repressing EWS-FLI1-Dependent IGF-1 Signaling.
abstract: Ewing sarcoma (EWS) is an aggressive bone malignancy that mainly affects children and young adults. The mechanisms by which EWS (EWSR1) fusion genes drive the disease are not fully understood. CRM1 (XPO1) traffics proteins from the nucleus, including tumor suppressors and growth factors, and is overexpressed in many cancers. A small-molecule inhibitor of CRM1, KPT-330, has shown therapeutic promise, but has yet to be investigated in the context of EWS. In this study, we demonstrate that CRM1 is also highly expressed in EWS. shRNA-mediated or pharmacologic inhibition of CRM1 in EWS cells dramatically decreased cell growth while inducing apoptosis, cell-cycle arrest, and protein expression alterations to several cancer-related factors. Interestingly, silencing of CRM1 markedly reduced EWS-FLI1 fusion protein expression at the posttranscriptional level and upregulated the expression of the well-established EWS-FLI1 target gene, insulin-like growth factor binding protein 3 (IGFBP3), which inhibits IGF-1. Accordingly, KPT-330 treatment attenuated IGF-1-induced activation of the IGF-1R/AKT pathway. Furthermore, knockdown of IGFBP3 increased cell growth and rescued the inhibitory effects on IGF-1 signaling triggered by CRM1 inhibition. Finally, treatment of EWS cells with a combination of KPT-330 and the IGF-1R inhibitor, linsitinib, synergistically decreased cell proliferation both in vitro and in vivo Taken together, these findings provide a strong rationale for investigating the efficacy of combinatorial inhibition of CRM1 and IGF-1R for the treatment of EWS. Cancer Res; 76(9); 2687-97. ©2016 AACR.
authors.affiliation: Immunogenetics and Transplantation Laboratory, Department of Surgery, University of California San Francisco, San Francisco, California. Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California. frenksun@gmail.com de-chen.Lin@cshs.org.
authors.forename: Haibo
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California. Cancer Science Institute of Singapore, National University of Singapore, Singapore. frenksun@gmail.com de-chen.Lin@cshs.org.
authors.forename: De-Chen
authors.initials: DC
authors.lastname: Lin
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Qi
authors.initials: Q
authors.lastname: Cao
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Xiao
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Helene
authors.initials: H
authors.lastname: Marijon
authors.affiliation: Department of Musculoskeletal Oncology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Sigal
authors.initials: S
authors.lastname: Gery
authors.affiliation: Cancer Science Institute of Singapore, National University of Singapore, Singapore.
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.affiliation: Cancer Science Institute of Singapore, National University of Singapore, Singapore.
authors.forename: Henry
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Pathology, National University Hospital Singapore, Singapore.
authors.forename: Brendan
authors.initials: B
authors.lastname: Pang
authors.affiliation: Department of Pathology, National University Hospital Singapore, Singapore.
authors.forename: Victor Kwan Min
authors.initials: VK
authors.lastname: Lee
authors.affiliation: Department of Pathology, National University Hospital Singapore, Singapore.
authors.forename: Huey Jin
authors.initials: HJ
authors.lastname: Lim
authors.affiliation: Department of Pathology and Laboratory Medicine, UCLA School of Medicine, Los Angeles, California.
authors.forename: Ngan
authors.initials: N
authors.lastname: Doan
authors.affiliation: Department of Pathology and Laboratory Medicine, UCLA School of Medicine, Los Angeles, California.
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Said
authors.affiliation: Department of Pathology, City of Hope National Medical Center, Los Angeles, California.
authors.forename: Peiguo
authors.initials: P
authors.lastname: Chu
authors.affiliation: Cancer Science Institute of Singapore, National University of Singapore, Singapore.
authors.forename: Anand
authors.initials: A
authors.lastname: Mayakonda
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Tom
authors.initials: T
authors.lastname: Thomas
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Charles
authors.initials: C
authors.lastname: Forscher
authors.affiliation: Karyopharm Therapeutics Inc, Newton, Massachusetts.
authors.forename: Erkan
authors.initials: E
authors.lastname: Baloglu
authors.affiliation: Karyopharm Therapeutics Inc, Newton, Massachusetts.
authors.forename: Sharon
authors.initials: S
authors.lastname: Shacham
authors.affiliation: Immunogenetics and Transplantation Laboratory, Department of Surgery, University of California San Francisco, San Francisco, California.
authors.forename: Raja
authors.initials: R
authors.lastname: Rajalingam
authors.affiliation: Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California. Cancer Science Institute of Singapore, National University of Singapore, Singapore. National University Cancer Institute, National University Hospital Singapore, Singapore.
authors.forename: H Phillip
authors.initials: HP
authors.lastname: Koeffler
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001859:Bone Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004357:Drug Synergism; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D015151:Immunoblotting; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D028884:Karyopherins / Q000037:antagonists & inhibitors*; D051379:Mice; D008819:Mice, Nude; D015514:Oncogene Proteins, Fusion / Q000378:metabolism*; D051789:Proto-Oncogene Protein c-fli-1 / Q000378:metabolism*; D011719:Pyrazines / Q000494:pharmacology; D034802:RNA-Binding Protein EWS / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors*; D012512:Sarcoma, Ewing / Q000378:metabolism / Q000473:pathology*; D015398:Signal Transduction / Q000502:physiology; D014230:Triazoles / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays; D000097606:Exportin 1 Protein
chemical_list: D006834:Hydrazines; D007093:Imidazoles; D007334:Insulin-Like Growth Factor I; D028884:Karyopherins; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D011719:Pyrazines; D034802:RNA-Binding Protein EWS; D018160:Receptors, Cytoplasmic and Nuclear; D014230:Triazoles; D000097606:Exportin 1 Protein; C551528:3-(8-amino-1-(2-phenylquinolin-7-yl)imidazo(1,5-a)pyrazin-3-yl)-1-methylcyclobutanol; C106031:EWS-FLI fusion protein; C585161:selinexor