Medical School of Uludag University, Department of Clinical Biochemistry, Bursa, Turkey
Cancer patients still need more effective therapies, especially chemotherapy-based treatments. According to the recently-published in vitro and in vivo studies, the combination of a general cytotoxic and a targeted therapy seems to yield much more successful outcomes. Therefore, a need for new general cytotoxics is still desirable. For this aim, the synthesis of new palladium (II) complexes provides a new arsenal. Therefore, the designation and creation of new palladium (II)-based compounds are in increase.
The bioinorganic and medicinal chemistry of 2,2':6',2''-terpyridine (terpy) complexes of Pd(II)  and Pt(II) [1, 2] is an active and growing area of interest. To date, many different compounds including palladium (II) as a metal have been synthesized and tested in terms of their cytotoxic activities against various tumor types. It seems that the ligands attached to the palladium (II) results in big differences in cytotoxic potential of the complexes. In the literature, varying ligands have already been used, such as pyrazoles, oxamate, triphenylphosphine, 2, 6-diacetylpyridine bis (p-chlorophenylthiosemicarbazone, thioures, hydrazine, tetraaza [N 4], sulfur, thiosemicarbazones, hydrazine, oxalato, proflavine, triazole, organoarsenic, curcumin. All these new Pd(II)-based compounds yield different cytotoxic potentials depending on the tumor types. In addition to the ligands above, the bioorganic and medicinal chemistry of 2,29:69,20-terpyridine (terpy) complexes of Pd(II) and Pt(II) is also an active and growing area of interest [3, 4]. We have investigated the anti-cancer activity of two different Pd (II) complexes of terpy with saccharinate (sac), one being formulated as [Pd(sac)(terpy)](sac)•4H2O and the other being as [Pd(Cl)(terpy)](sac)•2H2O.
These complexes were synthesized by our research group  and some publications were already made [5-7]. However, the little of them has been tested against the cancer stem cells, which are thought to be responsible drug resistance thereby causes recurrencies in the patients. It is needed to do extensive research on their effects on cancer stem cells either on their own or in combination with the other anticancer drugs/compounds.
Taken together, in this talk, novel Pd(II)-based compounds synthesized by the other groups will be discussed in comparison with our Pd(II)-based compounds in vitro and in vivo.
The experimental data given in this talk come from the projects supported by TUBITAK (The scientific and technological research council of Turkey) with the numbers of 212T147 and 114Z269.
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