Research Paper Human Exportin-1 is a Target for Combined Therapy of HIV and AIDS Related Lymphoma Eline Boons a,1 , Els Vanstreels a,1 , Maarten Jacquemyn a,1 , Tatiane C. Nogueira a , Jasper E. Neggers a , Thomas Vercruysse a , Joost van den Oord b , Sharon Tamir c , Sharon Shacham c , Yosef Landesman c , Robert Snoeck a , Christophe Pannecouque a , Graciela Andrei a , Dirk Daelemans a, ⁎ a KU Leuven, Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, B-3000 Leuven, Belgium b KU Leuven, Department of Imaging and Pathology, Translational Cell & Tissue Research, B-3000 Leuven, Belgium c Karyopharm Therapeutics, Newton 02459, MA, USA abstract article info Article history: Received 31 March 2015 Received in revised form 29 July 2015 Accepted 29 July 2015 Available online 1 August 2015 Keywords: Exportin-1 CRM1 XPO1 Small-molecule inhibitors HIV AIDS-related lymphoma Primary effusion lymphoma Infection with HIV ultimately leads to advanced immunodeficiency resulting in an increased incidence of cancer. For example primary effusion lymphoma (PEL) is an aggressive non-Hodgkin lymphoma with very poor progno- sis that typically affects HIV infected individuals in advanced stages of immunodeficiency. Here we report on the dual anti-HIV and anti-PEL effect of targeting a single process common in both diseases. Inhibition of the exportin-1 (XPO1) mediated nuclear transport by clinical stage orally bioavailable small molecule inhibitors (SINE) prevented the nuclear export of the late intron-containing HIV RNA species and consequently potently suppressed viral replication. In contrast, in CRISPR-Cas9 genome edited cells expressing mutant C528S XPO1, viral replication was unaffected upon treatment, clearly demonstrating the anti-XPO1 mechanism of action. At the same time, SINE caused the nuclear accumulation of p53 tumor suppressor protein as well as inhibition of NF-κB activity in PEL cells resulting in cell cycle arrest and effective apoptosis induction. In vivo, oral administra- tion arrested PEL tumor growth in engrafted mice. Our findings provide strong rationale for inhibiting XPO1 as an innovative strategy for the combined anti-retroviral and anti-neoplastic treatment of HIV and PEL and offer per- spectives for the treatment of other AIDS-associated cancers and potentially other virus-related malignancies. © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction The immune system of individuals infected with human immunode- ficiency virus (HIV) is gradually compromised and when untreated ulti- mately leads to advanced acquired immunodeficiency syndrome (AIDS), making patients vulnerable to opportunistic infections, malig- nancies, and other pathologies. Several different types of cancer are ob- served at an increased incidence in HIV-infected persons compared to the general population (Boshoff and Weiss, 2002; Cesarman, 2013). For example, primary effusion lymphoma (PEL) is a very aggressive non-Hodgkin Lymphoma (NHL) that most regularly appears in patients with major immunodeficiency, primarily in the context of HIV infection and advanced stages of AIDS. PEL is by definition associated with Kaposi's sarcoma-associated herpesvirus (KSHV, HHV-8) and most HIV-positive cases also show evidence of Epstein–Barr virus (EBV) infection (Cesarman, 2014). It originates within major body cavities such as the pleural, peritoneal spaces, or the pericardium. PEL has very poor prognosis with a survival time of two to three months after diagno- sis without treatment and only six months with aggressive chemother- apy (Chen et al., 2007). There is no standard therapy for the treatment of PEL and combination chemotherapy is considered first-line therapy (Chen et al., 2007; Kaplan, 2013). The use of anti-HIV drugs is associated with better prognosis suggesting antiretroviral therapy as part of the supportive treatment (Lim et al., 2005a; Boulanger et al., 2005). Other approaches outside traditional chemotherapy have been investigated, including the addition of anti-herpes therapy such as cidofovir (Halfdanarson et al., 2006) or the use of NF-κB inhibitors (Keller et al., 2006; An et al., 2004). Very recently, brentuximab vedotin (Bhatt et al., 2013a), which is an anti-CD30 monoclonal antibody conjugated to the microtubule-disrupting agent monomethyl auristatin E, and a proteasome-HDAC inhibitor combination (Bhatt et al., 2013b) have been demonstrated to be effective against PEL. Although patients dis- play response to therapy, remissions are often short-term and current chemotherapy approaches still result in poor outcome (Kaplan, 2012, 2013) warranting investigation of original therapeutic strategies for PEL. EBioMedicine 2 (2015) 1102–1113 ⁎ Corresponding author at: Laboratory of Virology and Chemotherapy, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium. E-mail address: dirk.daelemans@rega.kuleuven.be (D. Daelemans). 1 Equal contributing authors. http://dx.doi.org/10.1016/j.ebiom.2015.07.041 2352-3964/© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Contents lists available at ScienceDirect EBioMedicine journal homepage: www.ebiomedicine.com