The effect of the antiemetic chlorpromazine on bleomycin- and epirubicin cytotoxicity was tested in vitro. Chlorpromazine (0.1 or 0.01 rag/l) enhanced ...
Bioscience Reports, Vol. 10, No. 2, 1990
Different Effects of Chlorpromazine on Bleomycin- and Epirubicin Induced Cytotoxicity KjeH Grankvist, 1 Per Bergstriim and Roger Henriksson Received November 7, 1989
The effect of the antiemetic chlorpromazine on bleomycin- and epirubicin cytotoxicity was tested in vitro. Chlorpromazine (0.1 or 0.01 rag/l) enhanced epirubicin-induced toxicity to cultured Chinese fibroblasts whereas 0.01 mg/l chlorpromazine inhibited the cytotoxicity of Neomycin. The results encourage further studies on the effects of commonly used antiemetics on the cytotoxicity and antitumoral effects of anticancer chemotherapeutics. KEY WORDS: chlorpromazine, epirubicin, bleomycin, cytotoxicity.
INTRODUCTION Antiemetics are generally required during antineoplastic treatment. Chlorpromazine, the prototype of phenothiazines, has a potent and selective antiemetic action, and has been clinically applied in a number of disorders characterized by vomiting, such as carcinomatosis, radiation sickness, and emesis caused by drugs including chemotherapeutics. Recently, chlorpromazine has been suggested to interact with the cytotoxicity of antineoplastic agents. An enhancement of nitrosourea (Osieka et al., 1986) and epirubicin Henriksson and Grankvist, 1988) toxicity has been demonstrated in different experimental models. The phenomena of drug interaction is fraught with difficulties, and the complexity is further stressed by our finding that bleomycin and epirubicin cytotoxicity are affected in opposite directions when combined with chlorpromazine.
MATERIALS AND METHODS Cells and Incubations A Chinese fibroblast ceil line (V79-379A), propagated under standard tissue culture conditions was used. The nutrient medium consisted of Eagle's minimal Departments of Clinical Chemistry, and Oncology, Ume~t University Hospital, S-901 85 UME,~, Sweden, l To whom correspondence should be addressed.
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Grankvist, Bergstr6m and Henriksson
essential medium in Earle's saline (MEM), supplemented with 15% fetal calf serum and antibiotics. In short, the cells were incubated at 37~ in Eagle's MEM without calf serum. Petri dishes were incubated with or without chlorpromazine. After 30 min 1.0 mg/1 (final conc.) epirubicin or 10 mg/l (final conc.) bleomycin was added. In a separate set of experiments the effect of chlorpromazine alone was compared to untreated controls. The incubation was continued for 1 h, the dishes with the fibroblasts were rinsed twice with Eagle's MEM and then supplemented with MEM containing 15% calf serum. For each experiment, cells in exponential growth phase were trypsinized, monodispersed, counted, seeded into plastic Petri dishes and incubated in a CO2 incubator at 37~ The number of cells explanted were adjusted according to each epirubicin or bleomycin dose in such a way that 15 to 150 colonies could be expected to survive. After incubation for 7 days, the surviving clones were fixed and stained in situ. The number of surviving clones was defined as the percentage of treated clones that grew into macroscopic colonies as compared to control (untreated cells).
Chemicals
Epirubicin (4'-epidoxorubicin) as a crystalline powder was obtained as a kind gift from Farmitalia Carlo Erba, Milan, Italy. Bleomycin was from Lundbiick A / S , Copenhagen, Denmark. Eagle's minimal essential medium was from Gibco Ltd, Paisley, Scotland, UK. Fetal calf serum was obtained from Biochrom KG, Berlin, West Germany. Polystyrene Petri dishes were from Costar, Cambridge, MA, USA. Chlorpromazine was from Sigma Chemical Co., St Louis, MO, USA. All other chemicals were of analytical grade.
Statistics
Statistical significance of the difference between surviving clones were tested with Wilcoxon's rank sum test. The level of significance for rejecting the null hypothesis of zero treatment effect was taken to be P = 0.05.
RESULTS
As can be seen in Fig. 1, epirubicin and bleomycin caused a dose-dependent inhibition of the clonogenic survival (EDs0: Bleomycin 4.9mg/l; Epirubicin 0.35 mg/l). Chlorpromazine caused an enhancement of epirubicin-induced cytotoxicity (Table 1) in accordance with earlier observations (Osieka et al., 1986; Henriksson and Grankvist, (1988)). In contrast, the cytotoxicity of bleomycin was significantly decreased by 0.01 mg/1 chlorpromazine (Table 1). Chlorpromazine alone (0.01 or 0.1 mg/l) had no effect on the clonogenic survival as compared to untreated control (results not shown).
Chlorpromazine and Cytotoxicity
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~.~ 100 0
,~ 50 0
0
I
I
I
I
I
I
0.1
0.5
1.0
5.0
10
25
Drug concentration (rag/l)
Percentage of surviving clones relative to untreated control after 1 h treatment with epirubicin (e) or bleomycin (m). Mean • for 5-8 separate experiments.
Fig. 1.
DISCUSSION The diversity of chlorpromazine action is emphasized as the phenothiazines in common have many pharmacological actions and an amazingly large number of actions are manifested by chlorpromazine. These include gangliolytic, adrenolytic, antifibrillatory, antiedemic, antipyretic, antichock, anticonvulsant, and antiemetic properties. Furthermore, chlorpromazine enhances the activity of a number of analgetic and central depressant drugs, and markedly also affect the actions of other drugs ( G o o d m a n and Gilman, 1985). Thus it is obvious that complex reactions may occur when combining different agents with chlorpromazine. Table 1. Surviving clones (% of untreated controls) after
treatment with bleomycin (lOmg/1) or epirubicin (1 rag/l) in combination with chlorpromazine
-Chlorpromazine (0.1 mg/l) Chlorpromazine (0.01 mg/l)
Bleomycin
Epirubicin
20,9 + 3.3 19.4 + 1.9 33.5 + 1.6"*
4.4 + 0.7 0.5 + 0.1"** 1.8 + 0.3**
Mean +SEM for 11 separate experiments. *p
