Abstract B20: Development of metastatic patient-derived xenografts (PDXs) for accurate assessment of anti-metastatic therapeutics in pre-clinical settings

Abstract

Abstract Background: Although advances in treating early stage breast cancers have increased the overall survival rate, once the disease has metastasized treatment options subside to palliative care. The limited access to metastatic biopsies and disease-relevant pre-clinical models to test new therapeutics targeted against advanced metastatic cancers limits progress and translation of investigational therapeutics to the clinic. Methods: To address this deficiency we developed a collection of metastatic patient derived xenograft models via direct transplantation of metastatic biopsy or residual surgical material in immunocompromised mice. We successfully collected and established triple negative as well as ER/PR positive patient xenografts which are available for collaborative research. We further characterized and utilized the PDXs to assess the efficacy of new combination therapy to treat distant metastases. Results: The efficacy of Aurora A kinase inhibition by small molecule inhibitor MLN8237 (Alisertib) as monotherapy and in combination with microtubule targeting drug, eribulin, on different stages of metastasis and potential mechanisms of its action was defined. Our work using PDX models indicates that Alisertib does not limit growth of the primary tumor. These findings are similar to the results of clinical trials with Alisertib in breast cancer. Importantly, we found that Alisertib dramatically decreases growth of the established metastases and prevents further dissemination via inactivation of AKT and activation of cytotoxic autophagy. Combination of Alisertib with eribulin led to a synergistic decrease in metastases to distant organs and provided additional local control of mammary tumor growth. Conclusion: Metastatic PDX models provide new, accurate assessment of anti-metastatic regiment's efficacy. MLN8237 plus eribulin combination shows synergistic inhibition of metastatic spread, growth of established metastases and prolongs overall survival. Future clinical trials are needed to further test this regiment in clinic to improve survival of metastatic cancer patients. Citation Format: Ryan Ice, Anna Kiseleva, Yuriy Loskutov, Matthew Smolkin, Adham Salkeni, Hannah Hazard, Ginger Layne, Elena Pugacheva{Authors}. Development of metastatic patient-derived xenografts (PDXs) for accurate assessment of anti-metastatic therapeutics in pre-clinical settings. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B20.