| Autor: |
Dolgova EV; Laboratory of Induced Cell Processes, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia., Evdokimov AN; Laboratory of Bioorganic Chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia., Proskurina AS; Laboratory of Induced Cell Processes, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia., Efremov YR; Laboratory of Induced Cell Processes, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.; Natural Sciences Department, Novosibirsk State University, Novosibirsk, Russia., Bayborodin SI; Laboratory of Induced Cell Processes, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia., Potter EA; Laboratory of Induced Cell Processes, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia., Popov AA; Laboratory of Bioorganic Chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia., Petruseva IO; Laboratory of Bioorganic Chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia., Lavrik OI; Laboratory of Bioorganic Chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.; Natural Sciences Department, Novosibirsk State University, Novosibirsk, Russia.; Department of Physical Chemistry and Biotechnology, Altai State University, Barnaul, Russia., Bogachev SS; Laboratory of Induced Cell Processes, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia. |
| Abstrakt: |
Murine Krebs-2 tumor-initiating stem cells are known to natively internalize extracellular double-stranded DNA fragments. Being internalized, these fragments interfere in the repair of chemically induced interstrand cross-links. In the current investigation, 756 bp polymerase chain reaction (PCR) product containing bulky photoreactive dC adduct was used as extracellular DNA. This adduct was shown to inhibit the cellular system of nucleotide excision repair while being resistant to excision by this DNA repair system. The basic parameters for this DNA probe internalization by the murine Krebs-2 tumor cells were characterized. Being incubated under regular conditions (60 min, 24°C, 500 μL of the incubation medium, in the dark), 0.35% ± 0.18% of the Krebs-2 ascites cells were shown to natively internalize modified DNA. The saturating amount of the modified DNA was detected to be 0.37 μg per 10 6 cells. For the similar unmodified DNA fragments, this ratio is 0.73 μg per 10 6 cells. Krebs-2 tumor cells were shown to be saturated internalizing either (190 ± 40) × 10 3 molecules of modified DNA or (1,000 ± 100) × 10 3 molecules of native DNA. On internalization, the fragments of DNA undergo partial and nonuniform hydrolysis of 3' ends followed by circularization. The degree of hydrolysis, assessed by sequencing of several clones with the insertion of specific PCR product, was 30-60 nucleotides. |
