Abstract 5942: An integrated approach reveals novel extrinsic pathways and cytokine signatures associated with drug response in acute myeloid leukemia
Authors: Modak Rucha V. , Damnernsawad Alisa , Laderas Ted , Wu Guanming , Tyner Jeffery W. , Rodland Karin D. , McWeeney Shannon K. , Agarwal Anupriya 
Published: September 2020

Abstract
Background: Acute myeloid leukemia (AML) is a heterogeneous disease with a dismal 5 year survival rate below 30%. Current AML therapies have provided little improvement in achieving complete remission. This is attributed to the development of drug resistance and extrinsic factors from the microenvironment that promote AML progression. Previously, our lab demonstrated that proinflammatory cytokines from the bone marrow microenvironment such as IL-1, promote AML progression. This emphasizes the rationale to design and implement targeted therapies to block extrinsic pathways coupled with intrinsic pathways conferring drug resistance in AML.
Methods: To identify factors that promote drug sensitivity and resistance in AML, we used a cohort of 350 AML patients with various genetic subtypes. We quantified levels of 41 growth factors in plasma samples using a multiplex luminex assay. The same cohort of AML samples were analyzed for drug response to 130 small molecule inhibitors in in vitro functional drug sensitivity assay, for RNA-seq gene expression, and whole exome sequencing. The data was integrated to identify differential pathways and markers for drug response. To model drug response in vitro we created a series of drug resistant AML cell lines by culturing these cells in specific drugs long-term.
Results: Pathway analysis integrating drug sensitivity, transcriptome, and cytokine expression data identified distinct differentially regulated pathways for various inhibitors. We found that protein synthesis pathways were significantly enriched in sorafenib (FLT-3 inhibitor) resistant samples whereas cytokine and immune pathways (such as TLR and MCP1 signaling) were correlated with trametinib (MEK inhibitor) and venetoclax (Bcl-2 inhibitor) resistance. Specifically, venetoclax resistance correlated with augmented levels of cytokines such as IL-1 and IP-10 and growth factors such as PDGF. Further, trametinib resistance in AML samples is correlated with the upregulation of CCL11, MCP1, and TGFα but a downregulation of CCL22 levels. Accordingly, using AML cell line models, we observed an increase in MCP1 and TGFα at the transcript and secreted protein levels in trametinib resistant cell lines. We demonstrated that MCP1 stimulation activates survival pathways by activating pERK and pJNK signaling, thus reducing apoptosis in AML cells. Targeting MCP1 in combination with trametinib reverses these effects, thus offering a novel therapeutic approach to overcome drug resistance.
Conclusion and perspectives: Our data suggest that distinct extrinsic pathways may regulate the response to specific targeted therapy, thus providing a strong basis to design new treatment regimens. Combination treatment incorporating extrinsic pathways would aid in sensitizing AML cells to therapy. Our study offers an integrated approach and a resource to identify such pathways for a large number of tested drugs, and narrows down functionally important pathways associated with drug response.
Citation Format: Rucha V. Modak, Alisa Damnernsawad, Ted Laderas, Guanming Wu, Jeffery W. Tyner, Karin D. Rodland, Shannon K. McWeeney, Anupriya Agarwal. An integrated approach reveals novel extrinsic pathways and cytokine signatures associated with drug response in acute myeloid leukemia [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5942.