MANIFESTATIONS OF OXIDATIVE STRESS AND MOLECULAR DAMAGES IN OVARIAN CANCER TISSUE

Indices of oxidative stress are recognized molecular markers and prognostic criteria for malignant transformation of tissue, but their value depends on the type of tumor and the stage of its development. The goal of this study was to clarify the relationship between the characteristics of the oxidative stress system including metal-associated ones and the cytotoxicity manifestations in neoplastically transformed human ovarian tissue. The highest level of Mn-superoxide dismutase activity (by 630%) and metallothionein protein (MT, 100%) has been estimated for the first time in malignant ovarian tissue compared to normal ovarian tissue. The researchers have also found a much higher level of oxy-radical formation (by 332%), a lower activity of catalase (by 49%) and a lower level of reduced glutathione (by 46%) and its redox index (0.84 versus 0.89 in the control) in tumor tissue. Under the relatively stable content of zinc, copper and cadmium in MTs, the content of zinc and especially copper in a form non-binding with MTs was significantly lower in the malignant tissue compared to normal one while the content of cadmium was higher. A discriminant analysis of all definable parameters revealed that the higher content of the products of oxidative destruction of proteins, lipids, fragmented DNA and the activity of cathepsin D, especially in its free form (by 235%), are the main characteristic signs of malignant ovarian tissue.