Role of oligochitosans in regulation of cellular activity and location of pyruvate kinase (pk) isoenzyme m2 that affects proliferation of ehrlich ascites tumor cells (eat)

The pyruvate kinase isoenzyme M2 originating from the nucleoplasm and cytoplasm of tumor cells, with its highest affinity to the 2-phosphoenolpyruvate (2-PEP) and sensitivity to L-cysteine, contributes to an increased generation of energy as ATP, necessary for tumor cell proliferation. In the presence of L-cysteine, the isoenzyme M2 PK demonstrates the activity of histone kinase, transferring the phosphoryl group from 2-PEP to the ε-amine residue of the H1 histone lysine. Oligochitosans induce expression of the inducible nitric oxide synthase gene (iNOS), what results in an increased synthesis of nitric oxide, which reacts with L-cysteine and produces L-S-nitrosocysteine. Lack of L-cysteine contributes to inhibition of kinase activity of the H1 histone, an M2 PK isoenzyme. Decreased phosphorylation of the H1 histone contributes to inhibition of EAT cell proliferation. No effect on proliferation of normal cells that include the PK M1 isoenzyme has been observed in the presence of oligochitosans.