Effect of PSC 833, verapamil and amiodarone on adriamycin toxicity in cultured rat cardiomyocytes
Introduction
PSC 833 represents a novel class of agents that reverse multi-drug resistance (MDR) by inhibition of P-glycoprotein (Pgp). It thus inhibits Pgp-mediated efflux of anticancer drugs out of cancerous cells. Its preclinical and clinical applications are almost entirely free of side-effects. Although it belongs chemically to the class of cyclosporines, it is devoid of immunosuppressive activity. Concerning its in vitro pharmacological activity as a Pgp blocker, PSC 833 is about three to 10 times more potent than CsA, which is itself about one order of magnitude more potent than other known chemosensitizers, including verapamil, quinidine or amiodarone (Boesch et al., 1991, Twentyman and Bleehen, 1991).
Pgp blockers are used in combination with cytostatic drugs in order to increase the intratumoral concentration of cytostatic drugs without increasing their dose. The co-administration of cytostatic drugs with inhibitors of Pgp has raised questions of safety, since Pgp 170 is not only responsible for the extrusion of antineoplastic drugs from tumoral cells, but also from non-tumoral cells expressing Pgp, such as cardiomyocytes (Colombo et al., 1996). Cardiomyocytes moderately express Pgp in comparison to tumoral cells (Cayre et al., 1996; Furuya et al., 1994; Watanabe et al., 1995), thus an augmentation of adriamycin accumulation induced by Pgp blockers is probably lower for cardiomyocytes than for tumoral cells. However, since cardiotoxicity is a severe side-effect in chemotherapy, especially in the case of the very frequently used drug adriamycin, increased problems by co-administration with Pgp blockers might be expected (Eising et al., 1997, Rodriguez et al., 1999). Among the Pgp blockers, amiodarone and the (±)-racemate of verapamil, together with phenothiazines are very frequently administered in combination with cytostatic drugs in cancer chemotherapy (Van der Graaf et al., 1991, Pirker et al., 1995, Tolcher et al., 1996). The aim of the present study was to characterize, using a spontaneous contracting rat cardiac myocyte in vitro model, whether the effects of adriamycin (ADR) on cardiomyocyte viability and contractility are augmented by the Pgp blockers amiodarone, (±) verapamil and the non-immunosuppressive cyclosporine PSC 833.
Section snippets
Isolation and cultivation of rat cardiomyocytes
Primary cultures of heart myocytes from neonatal rats were prepared according to a published method (Lindl and Bauer, 1994). In brief, 10–12 neonatal (2–4 days old) Wistar rats (Wist/ICW, Iffa Credo) were sacrificed by decapitation; the hearts were excised and washed in ice-cold Hanks’ balanced salt solution (Ca2+ and Mg2+-free). The tissue was minced and sequentially digested in phosphate buffered saline (PBS) (Ca2+ and Mg2+-free; 5 mm glucose) containing 0.125% trypsin (Boehringer Mannheim,
Presence of P-glycoprotein in cultured cardiomyocytes
The presence of Pgp in the cultured neonatal cardiomyocytes was shown by double immunostaining of the fixed cardiomyocyte culture which, in addition to cardiomyocytes, also contains fibroblasts which are located between the cardiomyocytes. Cells were stained with the JSB1 antibody, which is specific for Pgp and an antisarcomeric α-actin antibody (Plate I). Actin myofilaments were labelled with FITC, which appeared as green fluorescence. Actin filaments showed the characteristic parallel
Discussion
Cardiomyocyte primary culture was chosen as an in vitro system to study the effects of the Pgp blockers PSC 833, verapamil and amiodarone on adriamycin induced cardiotoxicity. This in vitro system is well accepted and often used for in vitro investigations of cardiotoxic compounds (Davila et al., 1998) including adriamycin (Julicher et al., 1985). Its particular suitability for the present investigation was demonstrated, since it was possible to show for the first time the expression of Pgp in
Acknowledgements
The authors thank Mrs B. Greiner for her excellent technical assistance.
References (22)
- et al.
Isolation of rat Pgp3 cDNA: evidence for gender and zonal regulation of expression in the liver
Biochimica et Biophysica Acta
(1994) - et al.
In vitro toxicity screening using cultured rat skeletal muscle cells. II. Agents affecting excitable membranes
Toxicology in Vitro
(1994) - et al.
Interactions of cyclophilin with the mitochondrial inner membrane and regulation of the permeability transition pore, and cyclosporin A-sensitive channel
Journal of Biological Chemistry
(1996) - et al.
Increased toxicity of anthracycline antibiotics induced by calcium entry blockers in cultured cardiomyocytes
Toxicology and Applied Pharmacology
(1991) - et al.
Disruption of mitochondrial calcium homeostasis following chronic adriamycin administration
Toxicology and Applied Pharmacology
(1994) - et al.
Resistance modification by PSC 833, a novel non-immunosuppressive cyclosporine A
European Journal of Cancer
(1991) - et al.
In vivo circumvention of P-glycoprotein multidrug resistance of tumor cells with SDZ PSC 833
Cancer Research
(1991) - et al.
In vitro detection of the MDR phenotype in rat myocardium: use of PCR, 3H-daunomycin and MDR reversing agents
Anticancer Drugs
(1996) - et al.
Distribution and activity of adriamycin combined with SDZ PSC 833 in mice with P388 and P388/adriamycin leukaemia
British Journal of Cancer
(1996) - et al.
Predictive value of in vitro model systems in toxicology
Annual Review of Pharmacology and Toxicology
(1998)
Does the multidrug-resistance modulator cyclosporin A increase the cardiotoxicity of high-dose anthracycline chemotherapy?
Acta Oncologica
Cited by (32)
Nilotinib reverses ABCB1/P-glycoprotein-mediated multidrug resistance but increases cardiotoxicity of doxorubicin in a MDR xenograft model
2016, Toxicology LettersCitation Excerpt :Early reports raised questions of safety in the co-administration of cytotoxic drugs with P-gp inhibitors (van Waterschoot et al., 2009), since P-gp is not only responsible for the extrusion of antineoplastic drugs from MDR tumoral cells, but also responsible for the biodistribution and excretion of drugs from non-tumoral cells expressing P-gp, such as cardiomyocytes (Solbach et al., 2006). Co-administration of P-gp blockers (amiodarone, verapamil, or PSC 833) significantly increased DOX toxicity in cultured rat cardiomyocytes (Estevez et al., 2000). Furthermore, DOX accumulation was significantly increased in the brain and liver and DOX and DOXol retention in the heart were substantially prolonged in mdr1a-knockout mice (van Asperen et al., 1999).
Evaluation of the pharmacokinetics and cardiotoxicity of doxorubicin in rat receiving nilotinib
2013, Toxicology and Applied PharmacologyCitation Excerpt :Meanwhile, P-gp is our body's robust detoxification defense, serving as functional barriers against the entry of xenobiotics in the intestine and at the blood–brain barrier and contributing to drug excretion in the kidney, liver, and heart (Huls et al., 2009; Solbach et al., 2006, 2008). Previous studies had shown that combination with P-gp blockers (amiodarone, verapamil or PSC 833) significantly increased the toxicity of DOX in cultured rat cardiomyocytes (Estevez et al., 2000). Researchers had used mdr1a knockout mice and found that the accumulation of DOX was significantly increased in the brain and liver and the retention of both DOX and its metabolite doxorubicinol (DOXol) in the heart was substantially prolonged (van Asperen et al., 1999).
Acute exposure to doxorubicin results in increased cardiac P-glycoprotein expression
2011, Journal of Pharmaceutical SciencesCitation Excerpt :Furthermore, both proteins are expressed in the human heart. MRP1 localization was most prominent for cardiomyocytes,13 whereas P-gp was detected in vascular structures as well as in cardiomyocytes.14–16 Interestingly, a reduced cardiac P-gp expression was described for patients with dilative cardiomyopathy, whereas the expression of MRP1 was unchanged by heart failure.14,17