Targeting Promoter Regions Of C-Myc And Bcl-2 In Aml Cells Using G-Quadruplex Interacting Drugs

Cancer is a disease that can be characterized by overexpression of key oncogenic drivers that support tumor development and maintenance. In many instances, these oncogenic drivers are ‘undruggable’ because of structural challenges, the inability to effectively inhibit high concentrations of overexpressed proteins, and the development of drug resistance mutations. An alternative therapeutic approach is to directly inhibit gene transcription by targeting unique secondary DNA structures, called G-quadruplexes, that are associated with subsets of promoters. We investigated the activity of a class of compounds termed G-quadruplex Interacting Drugs (GQIDs) that are able to shut down the expression of specific oncogenic drivers, such as c-Myc and Bcl-2, used by tumor cells for growth and survival. We tested the activity of two GQIDs, GQC-05 and GSA-1103, on cell growth of a panel of eight pediatric and eight adult acute myeloid leukemia (AML) cell lines. Drug dose response analysis showed IC50 values ranging from approximately 10 nM to 1 μM for GQC-05 and from 40 nM to 2 μM for GSA-1103. The AML cell lines had different sensitivities to each GQID indicating a different mechanism of action for each compound. Three AML cell lines that were highly resistant to cytarabine were among the more sensitive to GQC-05. Four cell lines sensitive to GQC-05 had high expression of either c-Myc and/or Bcl-2, both of which are potential targets of these two GQIDs. Furthermore, treatment of the highly sensitive line MV-4-11 with GQC-05 showed a 3-4 fold decrease in expression of c-Myc and Bcl-2 mRNA. Furthermore, GQC-05 treatment resulted in decreased levels of both c-Myc and Bcl-2 proteins. These studies will help define a novel approach of repressing key drivers of leukemia by targeting selective promoter structures. Citation Format: Megan Turnidge, Justin J. Montoya, Apurvi Patel, David W. Lee, Eiman Aleem, Daniel H. Wai, Laurence H. Hurley, Vijay Gokhale, Robert J. Arceci, David O. Azorsa. Targeting promoter regions of c-Myc and Bcl-2 in AML cells using G-quadruplex interacting drugs. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3766.