title: 3,5-Dibenzoyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine (DP7) as a new multidrug resistance reverting agent devoid of effects on vascular smooth muscle contractility.
abstract: The aim of this study was to investigate the effects of 3,5-diacetyl- (DP1-DP5) and 3,5-dibenzoyl-1,4-dihydropyridines (DP6-DP11) on vascular functions in vitro, by comparing their mechanical and electrophysiological actions in rat aorta rings and single rat tail artery myocytes, respectively, and to quantify their multidrug resistance (MDR)-reversing activity in L5178 Y mouse T-lymphoma cells transfected with MDR1 gene. In rat aorta, the 11 compounds tested, but 3,5-dibenzoyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine (DP7), 3,5-dibenzoyl-4-(3-chlorophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP9), 3,5-dibenzoyl-4-(4-chlorophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP10) and 3,5-dibenzoyl-4-phenyl-1,4-dihydro-2,6-dimethylpyridine (DP11), antagonized 60 mm K+ (K60)-induced contraction in a concentration-dependent manner, with IC50 (m) values ranging between 5.65 x 10(-7) and 2.23 x 10(-5). The 11 dihydropyridines tested, but DP7, inhibited L-type Ca2+ current recorded in artery myocytes in a concentration-dependent manner, with IC50 (M) values ranging between 1.12 x 10(-6) and 6.90 x 10(-5). The K+ -channel opener cromakalim inhibited the Ca2+ -induced contraction in K30 but not that evoked in K60. On the contrary, DP7 was ineffective in both experimental conditions. When the rings were preincubated with 1 mm Ni2+ plus 1 microm nifedipine, the response to phenylephrine was significantly reduced by 2,5-di-t-butyl-1,4-benzohydroquinone (BHQ), a well-known endoplasmic reticulum Ca2+ -ATPase inhibitor. DP7 had no effects on this model system. In L5178 MDR cell line, the 11 dihydropyridines tested, but 3,5-diacetyl-4-(2-nitrophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP1), 3,5-diacetyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine (DP2) and 3,5-diacetyl-4-(3-chlorophenyl)-1,4-dihydro-2,6-dimethylpyridine (DP4), exhibited an MDR-reversing activity, with IC50 values ranging between 3.02 x 10(-7) and 4.27 x 10(-5), DP7 being the most potent. In conclusion, DP7 may represent a lead compound for the development of potent dihydropyridine MDR chemosensitizers devoid of vascular effects. British Journal of Pharmacology (2004) 141, 415-422. doi:10.1038/sj.bjp.0705635
authors.affiliation: Istituto di Scienze Farmacologiche, Università degli Studi di Siena, via A. Moro 2, 53100 Siena, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Saponara
authors.forename: Masami
authors.initials: M
authors.lastname: Kawase
authors.forename: Anamik
authors.initials: A
authors.lastname: Shah
authors.forename: Noboru
authors.initials: N
authors.lastname: Motohashi
authors.forename: Joseph
authors.initials: J
authors.lastname: Molnar
authors.forename: Katalin
authors.initials: K
authors.lastname: Ugocsai
authors.forename: Giampietro
authors.initials: G
authors.lastname: Sgaragli
authors.forename: Fabio
authors.initials: F
authors.lastname: Fusi
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D045744:Cell Line, Tumor; D004095:Dihydropyridines / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple / Q000187:drug effects* / Q000502:physiology; D007940:Leukemia L5178; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D014661:Vasoconstriction / Q000187:drug effects* / Q000502:physiology
chemical_list: C492000:3,5-dibenzoyl-4-(3-phenoxyphenyl)-1,4-dihydro-2,6-dimethylpyridine; D004095:Dihydropyridines