The Proapoptotic Action of Pyrrolidinedione–Thiazolidinone Hybrids towards Human Breast Carcinoma Cells Does Not Depend on Their Genotype.

Simple Summary: Breast cancer is one of the most frequent tumors worldwide, based on the number of new cases and deaths. Unfortunately, the low selectivity of action and the rapid development of multiple drug resistances remain the main disadvantages of anticancer compounds. The search for new agents with pronounced antitumor activity is an urgent task in modern biology and medicine. We focused on the investigation of the antitumor potential of novel hybrid pyrrolidinedione–thiazolidinone derivatives. The synthesized derivatives are effective and selective agents that exhibit their antitumor effects in breast carcinoma cells via (1) inhibiting viability, proliferation, and the ability to form colonies; (2) inducing extrinsic and intrinsic apoptotic pathways; and (3) decreasing the level of proteins associated with autophagy, invasion, and metastasis. Our results indicate that synthesized derivatives are potential candidates for deeper exploration of their therapeutic efficiency. The development of new, effective agents for the treatment of breast cancer remains a high-priority task in oncology. A strategy of treatment for this pathology depends significantly on the genotype and phenotype of human breast cancer cells. We aimed to investigate the antitumor activity of new pyrrolidinedione–thiazolidinone hybrid molecules Les-6287, Les-6294, and Les-6328 towards different types of human breast cancer cells of MDA-MB-231, MCF-7, T-47D, and HCC1954 lines and murine breast cancer 4T1 cells by using the MTT, clonogenic and [³H]-Thymidine incorporation assays, flow cytometry, ELISA, and qPCR. The studied hybrids possessed toxicity towards the mentioned tumor cells, with the IC₅₀ ranging from 1.37 to 21.85 µM. Simultaneously, these derivatives showed low toxicity towards the pseudonormal human breast epithelial cells of the MCF-10A line (IC₅₀ > 93.01 µM). Les-6287 at 1 µM fully inhibited the formation of colonies of the MCF-7, MDA-MB-231, and HCC1954 cells, while Les-6294 and Les-6328 did that at 2.5 and 5 µM, respectively. Les-6287 suppressed DNA biosynthesis in the MCF-7, MDA-MB-231, and HCC1954 cells. At the same time, such an effect on the MCF-10A cells was significantly lower. Les-6287 induces apoptosis using extrinsic and intrinsic pathways via a decrease in the mitochondrial membrane potential, increasing the activity of caspases 3/7, 8, 9, and 10 in all immunohistochemically different human breast cancer cells. Les-6287 decreased the concentration of the metastasis- and invasion-related proteins MMP-2, MMP-9, and ICAM-1. It did not induce autophagy in treated cells. In conclusion, the results of our study suggest that the synthesized hybrid pyrrolidinedione–thiazolidinones might be promising agents for treating breast tumors of different types. [ABSTRACT FROM AUTHOR]