ACETYLCHOLINESTERASE ACTIVITY IN BENIGN AND MALIGNANT BRAIN TUMOURS: THE COMPARATIVE ASSAY

Acetylcholinesterase participates in the regulation of cell proliferation and apoptosis and its activity is altered in different pathologies. The blood plasma acetylcholine and acetylcholine in the internal organs hydrolyzes with an alternative enzyme pseudocholinesterase. Nowadays it has been shown that cholinergic system, comprising acetylcholine, acetylcholine receptors and cholinesterases, is expressed by most human cell types and performs a critical role in the regulation of the basic functions of healthy and cancer cells. In the brain, acetylcholine acts as a neurotransmitter, but also as a local signaling molecule. Relationship between the cholinesterase activity in blood and in the tumor as well as the cancer-induced disturbances in the cholinergic system remain unclear. The aim of this research was a comparative assay of brain and blood acetylcholinesterase activity in patients with brain tumours. The blood and tissues of benign and malignant brain tumours processed for detection of acetylcholinesterase and pseudocholinesterase activities. The blood of healthy people and the brain tissue of died people were as a control. The significantly down-regulated acetylcholinesterase activity in the malignant brain tumours was correlated with the low acetylcholinesterase activity in erythrocytes (r 0,632). In the brain of patients with benign tumors, acetylcholinesterase activity did not significantly differ from the control values, the total cholinesterase activity of this group of patients also did not particularly differ from the blood values of healthy people. Analysis of blood plasma revealed no significant differences in pseudocholinesterase activity in patients with brain tumours and in the control group. The low acetylcholinesterase activity in patients with brain cancer may be due to the inhibition of apoptosis in the tumor. So, the blood acetylcholinesterase level is a promising prognostic predictor for the brain tumors malignancy and can be used for the differential diagnosis.