Melting of DNA from tumor-bearing rats treated with meso-Tetra(4-N-hydroxyethylpyridyl)porphyrin and its Ag, Zn, and Co derivatives

Abstract

The comparative study on the secondary structure of DNA isolated from the liver tissue of normal rats, as well as from the tumor tissue of rats both treated and untreated with porphyrins was carried out. meso- Tetra(4-N-hydroxyethylpyridyl)porphyrin and its Ag, Zn, Co derivatives (H₂TOEPyP4, AgTOEPyP4, ZnTOEPyP4, CoTOEPyP4) were studied as potential anticancer drugs. A method that allows revealing the conformational state of DNA via the study of the effects of transition metal ions, such as Mn²⁺, on the intramolecular melting was used in the work. DNA melting was carried out in the presence of different stoichiometric concentrations of Mn²⁺ ions. The main melting parameters, the melting temperature and the melting range (T_m and ΔT), were calculated. The melting parameters of DNA isolated from tumor tissue differed from those of normal DNA. The melting parameters of DNA isolated from rats treated with porphyrins were close to the normal ones. The results showed that AgTOEPyP4 and ZnTOEPyP4 have a better antitumor effect than H₂TOEPyP4 and CoTOEPyP4.