Κυτταρογενετικός έλεγχος της δράσης της ερυθροποιητίνης σε λεμφοκύτταρα περιφερικού αίματος ανθρώπου in vitro και σε καρκινικά κύτταρα P388 σε πειραματόζωα in vivo

Abstract

Erythropoietin (Epo) is a glycoprotein, which is produced mainly in the kidney section and secondarily in the liver. Its length is 165 aminoacetic residues and its molecular weight 30.4 kDa. Epo has multiple actions in the human organism. Its main action in the organism is the beginning of erythropoiesis, however, as it has been found, its presence in the organism has multiple beneficial results, like neuroprotection. Its action on the cells takes place via its binding with its receptor (EpoR), which, as it has been proved is inherent in many cells, among which, lymphocytes and cancer cells. In this study the action of Epo to the DNA of lymphocytes and murine P388 leukaemia cells has been analysed with one of the most sensitive cytogenetic methods, that of Sister Chromatid Exchanges (SCEs). SCEs are the genotoxicity index of the under review factor. Simultaneously with SCEs, two other indices were measured that are indicative of the promotion of cell cycle, the Proliferation Rate Index (P.R.I.), which is a cytostaticity index and the Mitotic Index (M.I.), which is a cytotoxicity index. The action of Epo on the lymphocytes has been studied both alone as well as in the presence of two chemotherapeutic factors that increase the fragility of DNA, thus augmenting the frequency of SCEs per metaphase. Those two factors are mitomycin C (MMC) and a camptothecin analogue, irinotecan (CPT-11). After cultivating cells in the presence of the studied factors, according to the related experimental protocol, and evaluating the results the following research results were reached: I. When Epo added alone to lymphocyte cultures and P388 leukemia cells, did not significantly alter any of the three cytogenetic indices. II. When Epo acted in combination with MMC, it reduced SCEs frequency and hence, the cultures where MMC and Epo were added showed lower SCEs frequency than that treated only with MMC. PRI and MI values of lymphocytes treated with the combination of the two agents are higher than that of lymphocytes treated only with MMC in the same concentration. The same findings for all the three cytogenetic indices, SCEs, PRI and MI were observed for P388 leukaemia cells in vivo. III. Epo and CPT-11 combinations decreased SCEs frequency in lymphocytes and P388 cells, in vitro and in vivo accordingly, compared to SCEs levels of cells treated only with CPT-11 in the same concentration. That proves the geno- and cytoprotective action of Epo against geno- and cytotoxic agents. Under Epo’s action and in presence of the cytostatic agent, the mitotic cycles of cells increased, compared to cells where only the cytostatic agent acted, 312 Η ΔΡΑ?Η ΣΗ? ΕΡΤΘΡΟΠΟΙΗΣΙΝΗ? ?ΣΑ ΦΡΩΜΑΣΟ?ΩΜΑΣΑ IN VITRO ΚΑΙ IN VIVO both in vitro as in vivo. PRIs and MIs of lymphocytes and murine P388 leukemia cells were higher for those treated with the combinations of the two agents than that treated only with CPT-11 in the same concentration. According to the aforementioned results and after the in vivo confirmation and clinical studies the following conclusions can be forwarded: I. Epo protects cells from the genotoxic action of both agents, MMC and CPT-11, by activating metabolic paths through its binding to EpoR, in vitro and in vivo. II. Epo’s genoprotective action may offer better survival to patients undergoing chemotherapy. Chemotherapy acts on a wide range of cells even when they are not its target. Epo’s administration to such patients may lower the genotoxic effect of chemotherapeutic drugs on those non-target cells if used in a special manner to achieve this. Administrating Epo in the forms of artificial analogues, such as rHuEpo, may offer special advantages to human body, which makes protein usage essential in a wide range of diseases