Fig. 1.

Synthesis and design of copper-bis-belinostat and its effect on colon cancer cell viability and belinostat metabolism in HLMs. a Introduction of a copper(II) ion to the hydroxamate moiety of two equimolar concentrations of belinostat afforded formation of novel prodrug copper-bis-belinostat (Cubisbel). b An MTT assay was performed on SW480, SW620 and CACO-2 cells after 24, 48 and 72 h of exposure to belinostat and Cubisbel respectively, ranging from 0.1875 µM to 20 µM. Data was plotted against % cell viability and normalized to the DMSO vehicle control. Data is expressed as means for six pooled values from three independent experiments (n = 3) ± SD. c Selected extracted ion chromatograms (EIC) of belinostat and belinostat glucuronide from HLM sample. d Percentage of belinostat remaining in HLM samples after 0, 30, 60 and 90 min incubation at 37°C with belinostat or Cubisbel HDACis. Points on the plot marked with an asterisk ‘*’ indicate a significant difference of % belinostat drug remaining between Cubisbel and belinostat treatments