Actinomycin D and staurosporine, potent apoptosis inducers in vitro, are potentially effective chemotherapeutic agents against glioblastoma multiforme.
OBJECTIVE
Although chemotherapeutic protocols that include chloroethylnitrosoureas (CENUs), such as 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) and 1, 3-bis(2-chloroethyl)-1-nitrosourea (BCNU), have been a mainstay of treatment for glioblastomas, the clinical outcomes have been unsatisfactory. More effective chemotherapeutic protocols for these tumors will require clear delineation of more cytocidal and cytostatic chemotherapeutic drugs.


RESULTS
In this study, we measured the cytocidal effects of ACNU, cisplatin, actinomycin D, and staurosporine, administered within their therapeutic dose ranges, in the treatment of glioblastoma cells. As assessed by WST-1 colorimetric assay, the number of viable cells decreased markedly in T98G cultures treated with actinomycin D or staurosporine, to less than 20% of the level in control cultures at 72 h, but did not decrease or even increased after 6 days of treatment with ACNU. After treatment with cisplatin for 5 days, cell viability decreased to 30% of control. As assessed by fluorescence microscopic examination of nuclear staining by Hoechst 33258 and by electron microscopy, the majority of dead cells treated with actinomycin D, staurosporine, or cisplatin had morphologic features of apoptosis. Caspase-3 activity increased more than 20-fold in cells treated with actinomycin D, staurosporine, or cisplatin but increased less than fivefold in ACNU-treated cells. In addition to caspase-3 activation, western blot analysis demonstrated cleavage of caspase-2 during the apoptotic process. These findings indicate that actinomycin D and staurosporine potently induce apoptosis, whereas ACNU exerts mainly a cytostatic rather than a cytocidal effect.


CONCLUSIONS
Actinomycin D and staurosporine and their derivatives are potentially effective chemotherapeutic agents against glioblastoma cells at least in vitro.
Narita
Y
Y
Laboratory for Neuroscience and Oncology, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113, Japan.
Asai
A
A
Kuchino
Y
Y
Kirino
T
T
D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D001932:Brain Neoplasms / Q000473:pathology*; D002945:Cisplatin / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005909:Glioblastoma / Q000473:pathology*; D006801:Humans; D015376:Nimustine / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000903:Antibiotics, Antineoplastic; D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D015376:Nimustine; D003609:Dactinomycin; D019311:Staurosporine; D002945:Cisplatin