Abstract 4569: Personalizing cancer therapy using dynamic BH3 profiling.
Authors: Montero Joan , Letai Anthony 
Published: August 2014

Abstract
Personalizing cancer therapy using dynamic BH3 profiling.
J. Montero, A. Letai.
Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA.
Background: There are many targeted therapies that lack effective predictive biomarkers. Many of these agents kill via the mitochondrial pathway of apoptosis. Apoptosis can be considered as a threshold, and we have designed a tool, BH3 profiling, that can measure mitochondrial ‘priming for death’, essentially the proximity of a cell to the this threshold of apoptosis. When effective death signaling is initiated by a targeted therapy, dynamic BH3 profiling can be used to measure the increase in mitochondrial priming caused by the agent within hours, without the requirement for prolonged ex vivo culture. This means that death signaling induced by any number of distinct agents can be simultaneously compared on a single cell line or primary tumor sample.
Hypothesis : Early apoptotic signaling detected via dynamic BH3 profiling can predict later cytotoxic cellular response.
Results: Our first test was whether dynamic BH3 profiling performed following only 16 hours of drug exposure could predict cytotoxicity at a much later (72-96 hours) time point. We initiated our studies on a diverse panel of cancer cell lines treated with a wide range of kinase inhibitors. These cell lines included: PC9 (NSCLC), K562 (CML), MCF7 (Breast Cancer), LP1 (Multiple Myeloma), DHL6 (Diffuse Large B cell lymphoma) and Sk5 mel (Melanoma) using nine different treatments (primary targets): gefitinib (EGFR inh), imatinib (BCR-ABL inh), lapatinib (HER2 inh), PD173074 (FGFR inh), TAE-684 (ALK inh), MK-2206 (Akt inh), PLX-4032 (BRaf V600E inh), AZD6244 (MEK inh) and BEZ235 (PI3K/mTOR inh). We observed a significant correlation between the increase in priming and cell death, demonstrating the predicting capacity of dynamic BH3 profiling in different cancer cells.
We also tested the predictive ability of dynamic BH3 profiling in chronic myelogenous leukemia (CML). We tested samples from stable phase CML patients of known clinical outcome who were either sensitive (underwent at least complete cytogenetic response) or refractory to clinical imatinib treatment. We found that the induction of mitochondrial priming caused by short term (16 hr) ex vivo exposure to imatinib predicted clinical response.
Conclusions: Our cell line and clinical experiments demonstrate the potential for dynamic BH3 profiling to be used as a powerful real time predictive tool across many cancers and many agents, including combinations of agents. This tool could be used to identify niche populations sensitive to an individual agent. Alternatively, it could be used to recognize the best agent from a list of possible therapies for an individual tumor and improve cancer therapy.
Citation Format: Joan Montero, Anthony Letai. Personalizing cancer therapy using dynamic BH3 profiling. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4569. doi:10.1158/1538-7445.AM2013-4569