Abstract 119: The influence of CD44/HA signaling on CML survival and resistance to tyrosine kinase inhibitor treatment

Abstract

The development of tyrosine kinase inhibitors (TKIs) such as imatinib has greatly improved the prognosis and survival of patients diagnosed with chronic myeloid leukemia (CML). However, many CML patients relapse due to the presence of minimal residual disease and the development of TKI resistance. It is unknown exactly what causes the relapse, but based on research from our laboratory we hypothesize that hyaluronic acid (HA) produced by fibroblasts in the microenvironment of the bone marrow provide for a protective environment preventing the tumor cells from therapy-induced cell death or senescence. The purpose of this study is to determine the influence that HA and its binding to its receptor (CD44) has on CML survival and resistance development. Initially, we examined the effect that stromal cell derived and/or exogenously added HA has on CML resistance to imatinib. Cell survival, apoptosis, HA production, and signaling events elicited by the interactions of HA with CD44 was examined using methods such as ELISA, western blotting, and MTT analysis. Furthermore, we examined the potential therapeutic use of compounds known to alter HA production and/or signaling for the treatment of CML. Our study demonstrates increased cell survival when the tumor cells are co-cultured with fibroblasts or have exogenous HA added to them after imatinib treatment. Additionally, we show that knocking out hyaluronic acid synthases reduces this protective effect. This data supports our hypothesis and we believe it could help lead to improved therapeutic treatment for CML. Note: This abstract was not presented at the meeting. Citation Format: Kylie Humphries, Olga Uchakina, Bryan Hostetler, Robert McKallip. The influence of CD44/HA signaling on CML survival and resistance to tyrosine kinase inhibitor treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 119.