Doxazosin induces apoptosis in cardiomyocytes cultured in vitro by a mechanism that is independent of α1-adrenergic blockade

University of Santiago de Compostela, Santiago, Galicia, Spain
Circulation (Impact Factor: 14.43). 02/2003; 107(1):127-31. DOI: 10.1161/01.CIR.0000043803.20822.D1
Source: PubMed


The alpha1-adrenoceptor-blocking antihypertensive doxazosin has been associated with increased risk of heart failure and is known to induce prostate cell apoptosis. We hypothesized that it might also induce apoptosis in cardiomyocytes.
Hoechst dye vital staining and flow cytometry provided evidence that doxazosin induced apoptosis time- and dose-dependently in cardiomyocytes of the HL-1 cell line. TUNEL assays and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) viability test confirmed that doxazosin induced DNA damage and cell death in these cells. MTT tests showed that doxazosin treatment decreased cell viability in primary cultures of neonatal rat cardiomyocytes, and Hoechst dye vital staining demonstrated doxazosin-induced apoptosis in primary cultures of human adult cardiomyocytes. The proapoptotic effect of doxazosin on cardiomyocytes seems not to depend on alpha1 blockade, because it was not modified by cotreatment with alpha- or beta-adrenergic agonists or with the irreversible alpha1-blocker phenoxybenzamine and because doxazosin also decreased the viability of NIH 3T3 cells, which lack alpha1-adrenoceptors. It also does not involve calcineurin, being unaffected by the presence of the calcineurin inhibitors cyclosporin A and FK506. Three other alpha1-blockers were also investigated; prazosin was proapoptotic, like doxazosin, but 5-methylurapidil and terazosin were not.
The alpha1-blockers doxazosin and prazosin induce the apoptosis of cardiomyocytes cultured in vitro by a mechanism that is independent of alpha1 blockade and calcineurin.

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Available from: Roberto Piñeiro, Jun 21, 2014
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    • "Cardiomyocytes from human atrial appendages, neonatal rat hearts, and HL-1 adult mouse atrial cardiomyocytes (a gift of Dr. W. C. Claycomb of Louisiana State University Medical Center, New Orleans, Louisiana) were all cultured as described previously (González-Juanatey et al., 2003). Briefly, HL-1 cardiomyocytes were cultured on fibronectin-coated plates with Claycomb medium supplemented with FBS, penicillin/streptomycin and L-glutamine. "
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    • "Moreover, hERG channels control cell proliferation and apoptosis [12]. Targeting of hERG channels by the small molecule α1-adrenoceptor antagonist doxazosin induces apoptosis in vitro independent of its anti-adrenergic function [13]–[15]. This pro-apoptotic mechanism of action was extended to structurally unrelated compounds, suggesting broader significance [11], [16]. "
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    • "Because of these attributes, even though HL-1 cells were originally derived from atrial myocytes, they have proven to be useful as a general model for studying contracting (working) cardiomyocytes because of their organized structure and ability to contract in culture [31]. They have been used as a cell culture model in numerous studies including apoptosis [58], [59], [60], [61], cell-cycle [15], electrophysiology [62], [63], [64], oxidative stress [65], [66], signal transduction [67], [68], [69], transcriptional regulation [65], [66], [70] and cellular transplantation [71]. However, it should be noted, that the results obtained are in adult cardiomyocytes and may differ for pre-natal or post natal myocytes. "
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