Pyrrolidinedithiocarbamate induces apoptosis in cerebellar granule cells: involvement of AP-1 and MAP kinases

Pyrrolidinedithiocarbamate (PDTC) is a compound displaying antioxidant, pro-oxidant and metal chelator properties in different cell types. It has been described that PDTC may exert either anti-apoptotic or apoptotic activity. Moreover it is known that this agent regulates the activity of redox-sensitive transcription factors, such as AP-1 and NF-kappaB. Using cerebellar granule cells (CGCs), a well-described model of neuronal primary cultures, we investigated the effects of different concentrations of this compound on cell viability and the intracellular mechanisms involved. PDTC used at concentrations, as low as 1 microM, exerts cytotoxic effects on CGC through the activation of the apoptotic machinery with a maximal efficacy for concentration of 10 microM. The PDTC-dependent apoptosis is correlated to a biphasic and long-lasting increase of AP-1 binding to the DNA, apparently without affecting the NF-kappaB whose activity was reduced only at much higher concentrations (100 microM). PDTC treatment enhanced ERK phosphorylation (maximal effect 1h) and p38 phosphorylation (maximal effect 7h) that was accompanied by an increase of both mRNA and protein of c-Jun. In conclusion the results presented show that PDTC exerts apoptotic effects on CGC, that are correlated to the activation of stress-pathways, involving mainly AP-1 and MAPKs.