Two approaches to novel anticancer agents. Small-molecule library synthesis and evaluation

Abstract

<p>The work presented in this dissertation combines two fully independent approaches to achieve compound libraries for anticancer drug research.

<p>Project 1: Development of compounds inhibiting human dUTPase as an amplifier of a thymidylate synthase inhibitor based cancer therapy

<p>The human dUTPase has received increased attention as a drug target in the recent years. Its inhibition can increase the efficacy of thymidylate synthase inhibitors in anticancer therapy. TAS-114 is the first human dUTPase inhibitor in clinical trials (phase 2). Based on the structure of TAS-114 and similar experimental dUTPase inhibitors, new dUTPase inhibitors were designed. One scaffold included a N,O-acetal structure element, connecting uracil with the imidazole scaffold. The thesis describes the attempts to synthesize the N,O-acetal by use of protected N1-chloromethyl uracil building blocks as alkylation agents. The synthesis of the four other scaffolds start from 2-imidazolecarboxaldehyde and ethyl imidazole-2-carboxylate as diversity platforms. The Mitsunubo reaction revealed a high potential for the connection of the imidazole building blocks with uracil and allowed short synthesis routes for new dUTPase targeting compounds. The synthesis routes were designed in a way that various scaffold types can be obtained from the intermediates. ITC-measurements delivered thermodynamic data for the tested compounds and exhibited low micromolar target affinities. Further, initial cell assay screenings are described.

<p>Project 2: Synthesis of dasatinib analogs enabled to form covalent connections with tyrosine kinases

<p>Covalent binding tyrosine kinase inhibitors have been the subject of increasing interest in the last decade. These inhibitors form a covalent bond with cysteine containing kinases, increasing their affinity and selectivity for a specific target. In project 2, the synthesis of potentially covalent binding dasatinib analogs is described. The bioactive core of dasatinib was modified for covalent binding. The compounds were tested for their affinity to different cysteine containing kinases. Covalent binding was not confirmed for the kinase BTK and KIT. Cell assays with different cancer cell lines expressing the kinases FLT3, BTK, and ITK, showed that three compounds significantly decreased cell viability relative to their reference compounds and dasatinib. These results indicate that covalent binding effects for some inhibitors may be present.