title: Synthesis, characterization, and molecular structure of a novel zinc (II) complex: assessment of impact of MDR1Pgp expression on its cytotoxic activity.
abstract: Zinc(II)complex (3) {bis(3-ethoxy-2-hydroxy-benzylidene)-N,N'-bis(2,2-dimethyl-3-aminopropyl)ethylenediamine}-zinc(II); [(3-OEt-ENBDMPI)Zn(II)] was obtained in situ by a ligand exchange reaction involving zinc(II) acetylacetonate and the Schiff-base ligand obtained in situ. For assessing ability of 3 to act as a transport substrate of multidrug resistance (MDR1) P-glycoprotein (Pgp), its cytotoxic activity was evaluated in human epidermal carcinoma drug-sensitive KB 3-1 (Pgp-) and drug resistant KB 8-5 (Pgp+) cells. Compared with its cationic gallium(III) counterpart 4 showing cytotoxicity profiles consistent with its recognition as a Pgp substrate, the neutral zinc(II) complex 3 did not display cytotoxicity profiles (at pharmacologically relevant concentrations <10 µM) modified by expression of Pgp. Further, 3 was found be slightly more toxic against KB 8-5 cells compared to KB 3-1 cells at higher concentration. The neutral zinc (II) complex 3 was also found to be considerably less toxic against Pgp-lacking cells compared to its cationic gallium(III) counterpart 4. Additionally, the neutral zinc(II) complex 3 demonstrated considerably more toxicity against Pgp expressing KB 8-5 cells (> 10 µM) compared with its cationic counterpart 4 displaying minimal effect at highest concentration. The results suggest that differential cytotoxic activity of 3 and 4 in drug-resistant human epidermal carcinoma KB 8-5 (Pgp+) cells could result from variation in the overall charge of the molecules.
authors.affiliation: BRIGHT Institute, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Harpstrite
authors.forename: Julie L
authors.initials: JL
authors.lastname: Prior
authors.forename: Jothilingam
authors.initials: J
authors.lastname: Sivapackiam
authors.forename: Silvia D
authors.initials: SD
authors.lastname: Collins
authors.forename: Nigam P
authors.initials: NP
authors.lastname: Rath
authors.forename: Vijay
authors.initials: V
authors.lastname: Sharma
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D018360:Crystallography, X-Ray; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D006801:Humans; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D015032:Zinc / Q000737:chemistry*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D009942:Organometallic Compounds; D015032:Zinc