1 Anikó Gaál, Loránd Eötvös University, Department of Inorganic and Analytical Chemistry, Institute of Chemistry, Budapest, Hungary
Introduction: A correlation has been suggested between metallothionein (MT) protein levels and the growth and invasiveness of certain tumors. Moreover, MT overexpressing cells and tissues show significant resistance to antitumor agents, like cisplatin or adriamycin. Chelating agents or metal complexes may be used for clinical use in the future, and their chemical-biological interaction with metallothionein overexpressing cells is unknown.
Aims: My goal was to create cell lines transfected with various metallothionein genes in order to examine the effect of different chelation treatments on the viability of the transfected cell lines compared to the vector control. I also aimed to study the changes of the intracellular metal contents.
Method: A series of MCF-7 and HT-29 cell lines transfected with hMT1a, hMT2a, and mouseMT genes were generated in order to examine the response of different chelation treatments (TPEN, COTI-2, DpC, neocuproine). Viability tests were performed with SRB and PrestoBlue tests and the determination of intracellular metal ion content was performed by TXRF method.
Results: We found no difference in intracellular metal contents on HT-29 cell line pairs. It is an interesting result that TPEN and DpC chelators do not cause any changes in any of the examined cases. However in the case of COTI-2, it can be seen that there was an increased efficiency on transfected HT-29 cells compared to the vector control cell line when using 100 µM zinc sulfate pretreatment. The vector control MCF-7 shows the normal IC50 value (1.5µM) in the case of treatment with copper chelator neocuproine, while the viability of the transfected cells increases fivefold. The transfected cells show a twofold resistance in the case of neocuproine-copper complex, which is much less, than in the case of cisplatin.
Conclusion: MT peptides do not exhibit significant resistance against the metal chelators (DpC, COTI-2) currently studied in clinical trials.
Doctoral School: Károly Rácz School of PhD Studies, Semmelweis University, Phamaceutical Sciences
Program: Experimental and Clinical Pharmacology
Supervisor: Norbert Szoboszlai
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