EFFECTS OF DIETHYLDITHIOCARBAMATE ON CALMODULIN IN NEUROBLASTOMA-CELLS

Diethyldithiocarbamate (DDC) was used to treat the neuroblastoma cell line Neuro-2a. Cell injury caused by DDC affects the calcium-binding p rotein calmodulin (CaM) and alters copper homeostasis in these cells. Neuro-2a cells were treated with 1 x 10(-5) M DDC for 1 h and were har vested at various time points over a 24-h period. Light microscopy of control cells showed CaM deposited around the cell periphery and along the neuritic processes. Treated cells showed the same distribution un til 3 h after treatment. Electron microscopy showed CaM deposited arou nd the cell periphery and within the cytoplasm and nucleus of control cells. Treated cells showed a time-dependent localization of CaM in re lation to cellular disorganization. Staining of electrophoretic transf ers by ProtoGold showed that CaM was present in all control samples an d treated samples through 6 h. Atomic absorption spectrophotometry sho wed no difference in calcium levels between control and treated sample s, but copper levels were significantly elevated. This study indicated that degenerative changes induced by DDC altered calmodulin levels. T hese changes may have been caused by elevated copper content within th e cells and subsequent cell injury.