Anticancer Properties of Peroxisome Proliferator-Activated Receptor Gamma (PPARγ) Potential Agonists 4-Thiazolidinone-Pyrazoline Hybrids Les-4368 and Les-4370 in Colorectal Adenocarcinoma Cells In Vitro

Presently, a major challenge is the search for new compounds that may exhibit an inhibitory effect on tumor progression. Recently, the 4-thiazolidinone (4-TZD) group has gained attention in this research field. The aim of the present study was to evaluate the anticancer effects of two new 4-TZD-based derivatives (Z)-5-[5-(2-hydroxyphenyl)- (Les- 4368) and (Z)-5-[5-(4-dimethylaminophenyl)-3-phenyl-4,5-dihydropyrazol-1-ylmethylene]-3-(3-acetoxyphenyl)-2-thioxothiazolidin-4-ones (Les-4370) on peroxisome proliferator-activated receptor gamma (PPARγ)-dependent cytotoxicity in human colorectal adenocarcinoma cells (CACO-2) and in normal human fibroblasts (BJ) in vitro. Les-4368 and Les-4370 exerted a toxic effect on both tested cell lines in high (micromolar) concentrations (10–100 µM). In addition, Les-4368 and Les-4370 applied in the BJ and CACO-2 cells in the concentration range of 10 µM to 100 µM increased the activity of caspase-3 and the production of reactive oxygen species (ROSs). The mRNA expression of PPARγ-related genes (PPARγ, AhR, PXR, and NF-κB) showed certain changes in these parameters, proving the engagement of this receptor in the induction of the biological effects of both tested 4-TZD derivatives. Moreover, the treatment of the BJ and CACO-2 cells with Les-4368, Les-4370, an antagonist (GW9662), or an agonist (rosiglitazone) of the PPARγ receptor also resulted in changes in the above-mentioned parameters. Unfortunately, the tested substances studied cell line work in a non-selective way at a relatively high concentration, which reduces their potential for clinical application. Our research is the preliminary study with the use of these compounds and requires further studies to elucidate the mechanisms of action of their anticancer potential.