Characterization and validation of a novel multitarget small-molecule in glioblastoma

The development of multitarget small molecules (MSMs) has emerged as a powerful strategy for the treatment of multifactorial diseases such as cancer. Glioblastoma is the most prevalent and malignant primary brain tumor in adults, which is characterized by poor prognosis and a high heterogeneity. Current standards of treatment present limited effectiveness, as patients develop therapy resistance and recur. In this work, we synthesized and characterized a novel multi-target molecule (named DDI199), which is a polyfunctionalized indole derivative developed by juxtaposing selected pharmacophoric moieties of the parent compounds Contilisant and Vorinostat (SAHA) to act as multifunctional ligands that inhibit histone deacetylases (HDACs), monoamine oxidases (MAOs) and cholinesterases (ChEs), and modulate histamine H3 (H3R) and 5-hydroxytryptamine 6 (5-HT6R) receptors. DDI199 exerts high cytotoxic activity in conventional glioblastoma cell lines and patient-derived glioma stem cells in vitro. Importantly, it significantly reduces tumor growth in vivo, both alone and in combination with temozolomide (TMZ). The comparison with SAHA showed higher target specificity and antitumor activity of the new molecule. Transcriptomic and proteomic analyses of patient-derived glioma stem cells revealed a deregulation in cell cycle and neurotransmission activity by the treatment with DDI199. In conclusion, our data reveal the efficacy of a novel MSM in glioblastoma pre-clinical setting. The experiment was performed in patient-derived glioma stem cells (GNS166) treated with DDI199 at 5μM and control for four independent replicates.