Alkoxyurea-Based Histone Deacetylase Inhibitors Increase Cisplatin Potency in Chemoresistant Cancer Cell Lines

The synthesis and biological evaluation of potent hydroxamate-based dual HDAC1/6 inhibitors with modest HDAC6 preference and a novel alkoxyurea connecting unit linker region are described. The biological studies included the evaluation of antiproliferative effects and HDAC inhibitory activity in the human ovarian cancer cell line A2780, the human squamous carcinoma cell line Cal27, and their cisplatin resistant sublines A2780CisR and Cal27CisR. The three most potent compounds <b>1g</b>–<b>i</b> showed IC₅₀ values in the low μM and sub-μM range. <b>1g</b>–<b>i</b> revealed low nM IC₅₀ values for HDAC6 with up to 15-fold preference over HDAC1, >3500-fold selectivity over HDAC4, and >100-fold selectivity over HDAC8. Furthermore, their ability to enhance cisplatin sensitivity was analyzed in Cal27 and Cal27CisR cells. Notably, a 48 h preincubation of <b>1g</b>–<b>i</b> significantly enhanced the antiproliferative effects of cisplatin in Cal27 and Cal27CisR. <b>1g</b>–<b>i</b> interacted synergistically with cisplatin. These effects were more pronounced for the cisplatin resistant subline Cal27CisR

Additional file 1: Figure S1. of MB3W1 is an orthotopic xenograft model for anaplastic medulloblastoma displaying cancer stem cell- and Group 3-properties

Phenotypical comparison of MB3W1 to other tumor cell lines.ᅟ (JPEG 2532 kb