Proliferation of cultured human astrocytoma cells in response to an oxidant and antioxidant.

The role of reactive oxygen species (ROS) in initiation, promotion and progression of several (lung, skin, colon, bladder, breast) tumors is well-documented. Indirect evidence for ROS involvement in tumor proliferation is provided by numerous in vivo and in vitro studies that show antioxidants inhibit tumor proliferation. However, despite strong epidemiological and experimental support for ROS involvement in brain tumor proliferation, to date little is known about the role of ROS in brain tumor promotion at a cellular level. In the present study ROS involvement in proliferation of a cultured, human astrocytoma cell line (U373-MG) was tested by studying effects of an oxidant (hydrogen peroxide, H2O2), and an antioxidant (N-acetylcysteine, NAC) on astrocytoma on proliferation of these cultured cells. Proliferation was assessed by evaluating changes in cell counts and DNA synthesis. Results from these experiments clearly indicate that NAC inhibits tumor cell proliferation and DNA synthesis induced by both serum and H2O2 (10(-5) M). NAC alone did not have any significant effects on the proliferation of serum-starved cells. Thus, ROS are capable of inducing proliferation in cultured astrocytoma cells and antioxidants block ROS- and serum-induced proliferation. Further investigation using primary cultures and animal models will be needed to substantiate the therapeutic potential of antioxidants in future brain tumor therapy.