- Ruthenium Complexes are pH-Activated Metallo Prodrugs (pHAMPs) with Light-Triggered Selective Toxicity Toward Cancer Cells
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Metallo prodrugs that take advantage of the inherent acidity surrounding cancer cells have yet to be developed. We report a new class of pH-activated metallo prodrugs (pHAMPs) that are activated by light- and pH-triggered ligand dissociation. These ruthenium complexes take advantage of a key characteristic of cancer cells and hypoxic solid tumors (acidity) that can be exploited to lessen the side effects of chemotherapy. Five ruthenium complexes of the type [(N,N)2Ru(PL)]2+ were synthesized, fully characterized, and tested for cytotoxicity in cell culture (1A: N,N = 2,2′-bipyridine (bipy) and PL, the photolabile ligand, = 6,6′-dihydroxybipyridine (6,6′-dhbp); 2A: N,N = 1,10-phenanthroline (phen) and PL = 6,6′-dhbp; 3A: N,N = 2,3-dihydro-[1,4]dioxino[2,3-f][1,10]phenanthroline (dop) and PL = 6,6′-dhbp; 4A: N,N = bipy and PL = 4,4′-dimethyl-6,6′-dihydroxybipyridine (dmdhbp); 5A: N,N = 1,10-phenanthroline (phen) and PL = 4,4′-dihydroxybipyridine (4,4′-dhbp). The thermodynamic acidity of these complexes was measured in terms of two pKa values for conversion from the acidic form (XA) to the basic form (XB) by removal of two protons. Single-crystal X-ray diffraction data is discussed for 2A, 2B, 3A, 4B, and 5A. All complexes except 5A showed measurable photodissociation with blue light (λ = 450 nm). For complexes 1A-4A and their deprotonated analogues (1B-4B), the protonated form (at pH 5) consistently gave faster rates of photodissociation and larger quantum yields for the photoproduct, [(N,N)2Ru(H2O)2]2+. This shows that low pH can lead to greater rates of photodissociation. Cytotoxicity studies with 1A-5A showed that complex 3A is the most cytotoxic complex of this series with IC50 values as low as 4 μM (with blue light) versus two breast cancer cell lines. Complex 3A is also selectively cytotoxic, with sevenfold higher toxicity toward cancerous versus normal breast cells. Phototoxicity indices with 3A were as high as 120, which shows that dark toxicity is avoided. The key difference between complex 3A and the other complexes tested appears to be higher uptake of the complex as measured by inductively coupled plasma mass spectrometry, and a more hydrophobic complex as compared to 1A, which may enhance uptake. These complexes demonstrate proof of concept for dual activation by both low pH and blue light, thus establishing that a pHAMP approach can be used for selective targeting of cancer cells.
- Qu, Fengrui,Park, Seungjo,Martinez, Kristina,Gray, Jessica L.,Thowfeik, Fathima Shazna,Lundeen, John A.,Kuhn, Ashley E.,Charboneau, David J.,Gerlach, Deidra L.,Lockart, Molly M.,Law, James A.,Jernigan, Katherine L.,Chambers, Nicole,Zeller, Matthias,Piro, Nicholas A.,Kassel, W. Scott,Schmehl, Russell H.,Paul, Jared J.,Merino, Edward J.,Kim, Yonghyun,Papish, Elizabeth T.
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supporting information
p. 7519 - 7532
(2017/07/12)
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- Luminescent ruthenium polypyridyl complexes with extended 'dppz' like ligands as DNA targeting binders and cellular agents
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Four new Ru(ii) polypyridyl complexes that contain an extended aromatic moiety derived from pyrazino[2,3-h]dipyrido[3,2-a:2′,3′-c]phenazine and either 1,10-phenanthroline (phen) or 1,4,5,8-tetraazaphenanthrene (TAP) have been synthesized, their solid state X-ray crystal structure determined and their photophysical and biological properties evaluated. Their interactions with DNA have been studied, and they have been tested for their potential as photodynamic therapeutic (PDT) agents in the treatment of cancer. A practical modification of a method by Carter, Rodriguez and Bard has been introduced and used to calculate binding parameters for the complexes which show a strong affinity for DNA with binding constants in the order of 107 M1 (in 10 mM phosphate buffer). The complexes containing phen as an ancillary ligand become emissive upon binding to DNA (“light switch effect”), but do not show selective cytotoxicity upon light irradiation. On the other hand, the TAP complexes, which show an inverse “light switch effect” (emission quenched upon binding to DNA), are strongly photo-toxic suggesting their use in Photodynamic Therapy (PDT). In HeLa cells the best PDT agent shows an IC50 value (light) = 4 μM vs. IC50 value (dark) = 62 μM.
- Poulsen, Bj?rn C.,Estalayo-Adrián, Sandra,Blasco, Salvador,Bright, Sandra A.,Kelly, John M.,Williams, D. Clive,Gunnlaugsson, Thorfinnur
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supporting information
p. 18208 - 18220
(2016/11/25)
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- RUTHENIUM FILM-FORMING MATERIAL AND RUTHENIUM FILM-FORMING METHOD
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Disclosed is a ruthenium film-forming material having a lower melting point and a higher vapor pressure that facilitates supply of the material onto a base and moreover enables a high-quality ruthenium film to be obtained. A ruthenium film-forming material includes a compound represented by general formula (1) below (wherein R1 is independently at each occurrence a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 4 carbon atoms or a halogenated hydrocarbon group having 1 to 4 carbon atoms; R2 is independently at each occurrence a halogenated hydrocarbon group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a halogenated alkoxy group having 1 to 4 carbon atoms, with the proviso that R1 and R2 are mutually differing groups; R3 is independently at each occurrence a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms; and L is an unsaturated hydrocarbon compound having 4 to 10 carbon atoms and having at least two double bonds).
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Page/Page column 9
(2012/11/13)
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