Cytotoxic effects of palladium complexes containing squaric ligands and sulfosuccinic acid on cancer cell lines

Background: Some metal complex derivatives can have an effective role in cancer treatment. The most common used components are platinum complexes which have numerous side effects, whereas, palladium complexes have shown fewer toxicity rate.

Methods: Some of palladium complexes were designed and synthesized for biological evaluation based on the squaric and sulfosuccinic acid ligands.

Results: the cytotoxic effects of the synthesized complexes, including 2-iodo squarato palladium (II), 2-iodo sulfosuccinate palladium (II) and 2-amino squarato palladium (II) on different cell lines (Hela, MCF-7, K562, and HUVEC) were examined. To determine the toxicity effect, lactate dehydrogenase (LDH) and trypan blue staining technique were used and the results were compared with cis-platinum. 

Conclusion: the analysis of binding of new groups to palladium showed higher toxicity of 2-iodo sulfosuccinate palladium on normal cells than control compound. The comparison of compounds indicated that amino group increased the efficacy. Replacement of ion atoms by amino group in 2-amino squarato palladium enhanced the efficacy of the compound on cancer cell lines. 2-amino squarato palladium exerted the maximum effect on PC3 cell line and the minimum effect on Hela with IC50s of 4.33 µM and 18.88µM, respectively. Moreover, 2-amino squarato palladium (II) indicated less toxicity on HUVEC in comparison to cis-platinum.