In Vitro And In Vivo Antitumor Activity Of The Selective Alk Inhibitor Asp3026 Against Npm-Alk Plus T-Cell Anaplastic Large-Cell Lymphoma

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase with structural similarities to the insulin receptor. ALK is physiologically expressed in neuronal cells at early stages of human development. Thereafter, ALK expression is largely limited to malignant neoplasms including T-cell anaplastic large-cell lymphoma (ALCL), non-small cell lung cancer (NSCLC), and neuroblastoma. It has been previously established that ALK, in the form of chimeric proteins or constitutively activated mutants, plays a central role in the survival of these tumors. Hence, targeting ALK is considered a legitimate and likely successful strategy to eradicate these tumors. Nucleophosmin-ALK-expressing (NPM-ALK+) T-cell ALCL is an aggressive type of cancer. It is one of the most common hematological neoplasms in children as it comprises 40% of the non-Hodgkin lymphomas in this age group. Recently, a selective ALK inhibitor, ASP3026, was developed utilizing an ALK kinase inhibition assay aimed at the chimeric tyrosine kinase echinoderm-microtubule-associated protein-like 4-ALK (EML4-ALK), which is expressed in a subgroup of NSCLC tumors.1 Initial studies showed that not only ASP3026 possesses remarkable inhibitory effects on EML4-ALK but also it overcomes the resistance of EML4-ALK+ NSCLC to crizotinib; a prototype ALK and c-MET inhibitor. ASP3026 is currently being tested in phase I clinical trials that include EML4-ALK+ NSCLC patients. Of important note is that the effects and therapeutic potential of ASP3026 in NPM-ALK+ T-cell ALCL are not known. We systematically analyzed the effects of ASP3026 (ChemieTek, Indianapolis, IN) in NPM-ALK+ T-cell ALCL using in vitro and in vivo experimental approaches. ASP3026 (0.1 to 3.0 µM; 24 and 72 h) induced a concentration- and time-dependent decrease in the viability and proliferation of NPM-ALK+ T-cell ALCL cell lines including Karpas 299, SU-DHL-1, SUP-M2, SR-786, and DEL. In contrast, these negative effects were not observed in normal human T lymphocytes. Furthermore, ASP3026 reduced anchorage-independent colony formation of NPM-ALK+ T-cell ALCL cells. The effects of ASP3026 could be explained, at least in part, by successful induction of apoptotic cell death in these cells. At the biochemical level, ASP3026 decreased significantly the levels of pNPM-ALK and the activated/phosphorylated form of its interacting oncogenic protein type I insulin-like growth factor receptor (pIGF-IR). We are performing additional experiments to further characterize the biochemical effects of ASP3026 in NPM-ALK+ T-cell ALCL cells. To further evaluate the therapeutic potential of ASP3026, we utilized an in vivo systemic lymphoma model developed in our laboratory. Briefly, Karpas 299 cells (1 × 106 cells per mouse), engineered to simultaneously express humanized firefly luciferase and GFP, were injected intravenously in CB-17 SCID mice (Taconic; female; 6-8 weeks old). Systemic lymphoma tumors, detected by using IVIS whole body imaging system after intraperitoneal injection of D-lucifern, were established at approximately 3 weeks after lymphoma cell injections.Thereafter, vehicle or ASP3026 (30 mg/kg/day) was administered daily to the mice (10 mice per group) through oral gavage. Also, standard CHOP combination chemotherapy was used in another group. Treatment with ASP3026 for only 2 weeks was associated with complete lymphoma eradication, which persisted with the daily administration of ASP3026 and until study termination at 6-8 weeks from treatment initiation. In contrast, cessation of ASP3026 after 2 weeks of treatment was associated with lymphoma relapse. Although CHOP initially eradicated the lymphoma, most of the CHOP-treated mice developed significant toxicity and relapsed at 4 weeks after treatment. Importantly, vehicle- and CHOP-treated mice had inferior overall survival compared with mice treated with ASP3026. Taken together, our results provide strong evidence that ASP3026 could represent a novel approach to efficiently treat NPM-ALK+ T-cell ALCL. 1Kuromitsu S, et al. Mol. Cancer Ther. 2011;10[Supp. 1]: A227 DV and SKG equally contributed to this work Citation Format: Deeksha Vishwamitra, Suraj Konnath George, Roxsan Manshouri, Ping Shi, Hesham M. Amin. In vitro and in vivo antitumor activity of the selective ALK inhibitor ASP3026 against NPM-ALK+ T-cell anaplastic large-cell lymphoma. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A80.