Thiazolidinone/thiazole based hybrids - New class of antitrypanosomal agents

Different compounds have been investigated as potent drugs for trypanosomiasis treatment, but no new drug has been marketed in the past 3 decades. 4-Thiazolidinone/thiazole as privileged structures and thiosemicarbazides cyclic analogs are well known scaffolds in novel antitrypanosomal agent design. We present here the design and synthesis of new hybrid molecules bearing thiazolidinone/thiazole cores linked by the hydrazone group with various molecular fragments. Structure optimization led to compounds with phenyl-indole or phenyl-imidazo[2,1-b][1,3,4]thiadiazole moieties showing excellent antitrypanosomal activity towards Trypanosoma brucei brucei and Trypanosoma brucei gambiense. Biological study allowed identifying compounds with the submicromolar levels of IC₅₀, good selectivity indexes and relatively low cytotoxicity upon human primary fibroblasts as well as low acute toxicity.

Synthesis of imidazo-thiadiazole linked indolinone conjugates and evaluated their microtubule network disrupting and apoptosis inducing ability

A series of imidazo[2,1-b][1,3,4]thiadiazole linked indolinone conjugates were synthesized and investigated for antiproliferative activity in different human cancer cell lines by changing various substitutions at indolinone and phenyl ring systems. Among them conjugates 7, 14 and 15 were exhibited potent antiproliferative activity with GI₅₀ values from 0.13 to 3.8 μΜ and evaluated for cell cycle analysis, tubulin polymerization assay and apoptosis. Treatment with 7, 14 and 15 were resulted in accumulation of cells in G2/M phase, inhibition of tubulin assembly, disruption of microtubule network. Inhibition of tubulin polymerization was further supported by Western blot analysis. In addition, the conjugates (7, 14 and 15) also showed apoptosis in HeLa cell line, detailed biological studies such as Hoechst 33,258 staining, DNA fragmentation and caspase-3 assays suggested that these compounds induce cell death by apoptosis. Docking studies revealed that these compounds (7, 14 and 15) bind with αAsn101, αThr179, αSer178, βCys241, βLys254 and βLys352 in the colchicine-binding site of the tubulin.

QSAR models of antiproliferative activity of imidazo[2,1-b][1,3,4]thiadiazoles in various cancer cell lines

Imidazo[2,1-b][1,3,4]thiadiazoles have been recognized to possess antiproliferative potency towards a wide spectrum of cancer cell lines. QSAR investigations on a set of 42 di(tri)substituted imidazo[2,1-b][1,3,4]thiadiazoles were carried out to find the descriptors determining their biological potency. Three-variable equations were obtained by combinatorial protocols in multiple linear regression (CP MLR) for all three studied cancer cell lines. They showed that lipophilicity, electronic, and steric factors are decisive for the antiproliferative potency of compounds and indicate the important role of nitrogen atoms of imidazothiadiazole ring in the interactions with the molecular target. The best models gave high r squared values in the range from 0.887 to 0.924. They also have good predictive accuracy confirmed by the high value LOO cross-validation coefficient [Formula: see text] (from 0.842 to 0.904) and by the external validation quantities.