Neuron-specific enolase is a useful marker of neuroendocrine origin in pheochromocytoma cell culture

RESUMO

Neuron-specific enolase (NSE) has been used as a marker for neuroendocrine tumors either in immunocytochemical studies or in serum measurements. ln this paper NSE levels were determined in cultured pheochromocytoma cells to test whether it is also a useful marker ín cell culture of tumors derived from neuroendocrine system. Cultured pheochromocytoma cells came from a primary explant and were grown in RPMI supplemented with 20 per cent fetal calf serum, 100 mug/mL ampicillin and 100 mug/mL streptomycin. NSE was measured in culture medium and cell homogenates. Samples from different pheochromocytoma cultures were analyzed and compared to normal cultured fibroblast cells derived from human skin. NSE was measured by a commercially available radioimmunoassay kit. NSE levels were higher in cell homogenates as compared to those in culture medium, reaching levels as high as 6-fold in the former in TE cell line (26.46 ng/mL and 4.39 ng/mL respectively. Serial NSE measurements in culture medium from TE cell line evidenced decreasing values in subsequential subcultures (from 9.24 ng/mL during primary explant to 1.7 ng/ml. in the 10th subculture). In cultured normal fibroblasts, NSE levels in cultured media were definitely lower than those obtained from pheochromocytoma cultures. These preliminary data suggest that NSE may be a useful marker of neuroendocrine derived tumors, such as pheochromocytoma, in culture. Thus, the simplicity and availability of NSE radioimmunoassay provides an alternative to catecholamine measurement to better characterize pheochromocytoma cell lines in culture, with the advantage of faster results at lower costs.