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Cole HD, Vali A, Roque JA, Shi G, Talgatov A, Kaur G, Francés-Monerris A, Alberto ME, Cameron CG, McFarland SA. Ru(II) Oligothienyl Complexes with Fluorinated Ligands: Photophysical, Electrochemical, and Photobiological Properties. Inorg Chem 2024. [PMID: 38728376 DOI: 10.1021/acs.inorgchem.3c04382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
A series of Ru(II) complexes incorporating two 4,4'-bis(trifluoromethyl)-2,2'-bipyridine (4,4'-btfmb) coligands and thienyl-appended imidazo[4,5-f][1,10]phenanthroline (IP-nT) ligands was characterized and assessed for phototherapy effects toward cancer cells. The [Ru(4,4'-btfmb)2(IP-nT)]2+ scaffold has greater overall redox activity compared to Ru(II) polypyridyl complexes such as [Ru(bpy)3]2+. Ru-1T-Ru-4T have additional oxidations due to the nT group and additional reductions due to the 4,4'-btfmb ligands. Ru-2T-Ru-4T also exhibit nT-based reductions. Ru-4T exhibits two oxidations and eight reductions within the potential window of -3 to +1.5 V. The lowest-lying triplets (T1) for Ru-0T-2T are metal-to-ligand charge-transfer (3MLCT) excited states with lifetimes around 1 μs, whereas T1 for Ru-3T-4T is longer-lived (∼20-24 μs) and of significant intraligand charge-transfer (3ILCT) character. Phototoxicity toward melanoma cells (SK-MEL-28) increases with n, with Ru-4T having a visible EC50 value as low as 9 nM and PI as large as 12,000. Ru-3T and Ru-4T retain some of this activity in hypoxia, where Ru-4T has a visible EC50 as low as 35 nM and PI as high as 2900. Activity over six biological replicates is consistent and within an order of magnitude. These results demonstrate the importance of lowest-lying 3ILCT states for phototoxicity and maintaining activity in hypoxia.
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Affiliation(s)
- Houston D Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Abbas Vali
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - John A Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Ge Shi
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Alisher Talgatov
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Gurleen Kaur
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | | | - Marta E Alberto
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Arcavacata di Rende 87036, Italy
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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Cole HD, Vali A, Roque JA, Shi G, Kaur G, Hodges RO, Francés-Monerris A, Alberto ME, Cameron CG, McFarland SA. Ru(II) Phenanthroline-Based Oligothienyl Complexes as Phototherapy Agents. Inorg Chem 2023; 62:21181-21200. [PMID: 38079387 PMCID: PMC10754219 DOI: 10.1021/acs.inorgchem.3c03216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
Ru(II) polypyridyl complexes have gained widespread attention as photosensitizers for photodynamic therapy (PDT). Herein, we systematically investigate a series of the type [Ru(phen)2(IP-nT)]2+, featuring 1,10-phenanthroline (phen) coligands and imidazo[4,5-f][1,10]phenanthroline ligands tethered to n = 0-4 thiophene rings (IP-nT). The complexes were characterized and investigated for their electrochemical, spectroscopic, and (photo)biological properties. The electrochemical oxidation of the nT unit shifted by -350 mV as n = 1 → 4 (+920 mV for Ru-1T, +570 mV for Ru-4T); nT reductions were observed in complexes Ru-3T (-2530 mV) and Ru-4T (-2300 mV). Singlet oxygen quantum yields ranged from 0.53 to 0.88, with Ru-3T and Ru-4T being equally efficient (∼0.88). Time-resolved absorption spectra of Ru-0T-1T were dominated by metal-to-ligand charge-transfer (3MLCT) states (τTA = 0.40-0.85 μs), but long-lived intraligand charge-transfer (3ILCT) states were observed in Ru-2T-4T (τTA = 25-148 μs). The 3ILCT energies of Ru-3T and Ru-4T were computed to be 1.6 and 1.4 eV, respectively. The phototherapeutic efficacy against melanoma cells (SK-MEL-28) under broad-band visible light (400-700 nm) increases as n = 0 → 4: Ru-0T was inactive up to 300 μM, Ru-1T-2T were moderately active (EC50 ∼ 600 nM, PI = 200), and Ru-3T (EC50 = 57 nM, PI > 1100) and Ru-4T (EC50 = 740 pM, PI = 114,000) were the most phototoxic. The activity diminishes with longer wavelengths of light and is completely suppressed for all complexes except Ru-3T and Ru-4T in hypoxia. Ru-4T is the more potent and robust PS in 1% O2 over seven biological replicates (avg EC50 = 1.3 μM, avg PI = 985). Ru-3T exhibited hypoxic activity in five of seven replicates, underscoring the need for biological replicates in compound evaluation. Singlet oxygen sensitization is likely responsible for phototoxic effects of the compounds in normoxia, but the presence of redox-active excited states may facilitate additional photoactive pathways for complexes with three or more thienyl groups. The 3ILCT state with its extended lifetime (30-40× longer than the 3MLCT state for Ru-3T and Ru-4T) implicates its predominant role in photocytotoxicity.
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Affiliation(s)
- Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 USA
| | - Abbas Vali
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 USA
| | - John A. Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 USA
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402 USA
| | - Ge Shi
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 USA
| | - Gurleen Kaur
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 USA
| | - Rachel O. Hodges
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402 USA
| | | | - Marta E. Alberto
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Arcavacata di Rende, 87036 Italy
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 USA
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 USA
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Azad AK, Lilge L, Usmani NH, Lewis JD, Cole HD, Cameron CG, McFarland SA, Dinakaran D, Moore RB. High quantum efficiency ruthenium coordination complex photosensitizer for improved radiation-activated Photodynamic Therapy. Front Oncol 2023; 13:1244709. [PMID: 37700826 PMCID: PMC10494715 DOI: 10.3389/fonc.2023.1244709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 08/08/2023] [Indexed: 09/14/2023] Open
Abstract
Traditional external light-based Photodynamic Therapy (PDT)'s application is limited to the surface and minimal thickness tumors because of the inefficiency of light in penetrating deep-seated tumors. To address this, the emerging field of radiation-activated PDT (radioPDT) uses X-rays to trigger photosensitizer-containing nanoparticles (NPs). A key consideration in radioPDT is the energy transfer efficiency from X-rays to the photosensitizer for ultimately generating the phototoxic reactive oxygen species (ROS). In this study, we developed a new variant of pegylated poly-lactic-co-glycolic (PEG-PLGA) encapsulated nanoscintillators (NSCs) along with a new, highly efficient ruthenium-based photosensitizer (Ru/radioPDT). Characterization of this NP via transmission electron microscopy, dynamic light scattering, UV-Vis spectroscopy, and inductively coupled plasma mass-spectroscopy showed an NP size of 120 nm, polydispersity index (PDI) of less than 0.25, high NSCs loading efficiency over 90% and in vitro accumulation within the cytosolic structure of endoplasmic reticulum and lysosome. The therapeutic efficacy of Ru/radioPDT was determined using PC3 cell viability and clonogenic assays. Ru/radioPDT exhibited minimal cell toxicity until activated by radiation to induce significant cancer cell kill over radiation alone. Compared to protoporphyrin IX-mediated radioPDT (PPIX/radioPDT), Ru/radioPDT showed higher capacity for singlet oxygen generation, maintaining a comparable cytotoxic effect on PC3 cells.
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Affiliation(s)
- Abul Kalam Azad
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
| | - Lothar Lilge
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Nawaid H. Usmani
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
| | - John D. Lewis
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, United States
| | - Deepak Dinakaran
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Radiation Oncology Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, United States
| | - Ronald B. Moore
- Department of Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Surgery, University of Alberta, Edmonton, AB, Canada
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Chettri A, Yang T, Cole HD, Shi G, Cameron CG, McFarland SA, Dietzek-Ivanšić B. Using Biological Photophysics to Map the Excited-State Topology of Molecular Photosensitizers for Photodynamic Therapy. Angew Chem Int Ed Engl 2023; 62:e202301452. [PMID: 36827484 PMCID: PMC10079593 DOI: 10.1002/anie.202301452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 02/26/2023]
Abstract
This study employs TLD1433, a RuII -based photodynamic therapy (PDT) agent in human clinical trials, as a benchmark to establish protocols for studying the excited-state dynamics of photosensitizers (PSs) in cellulo, in the local environment provided by human cancer cells. Very little is known about the excited-state properties of any PS in live cells, and for TLD1433, it is terra incognita. This contribution targets a general problem in phototherapy, which is how to interrogate the light-triggered, function-determining processes of the PSs in the relevant biological environment, and establishes methodological advances to study the ultrafast photoinduced processes for TLD1433 when taken up by MCF7 cells. We generalize the methodological developments and results in terms of molecular physics by applying them to TLD1433's analogue TLD1633, making this study a benchmark to investigate the excited-state dynamics of phototoxic compounds in the complex biological environment.
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Affiliation(s)
- Avinash Chettri
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745, Jena, Germany
- Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Tingxiang Yang
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745, Jena, Germany
- Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Houston D Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX-76019, USA
| | - Ge Shi
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX-76019, USA
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX-76019, USA
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX-76019, USA
| | - Benjamin Dietzek-Ivanšić
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745, Jena, Germany
- Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
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Cole HD, Eroy M, Roque JA, Shi G, Guirguis M, Fakhry J, Cameron CG, Obaid G, McFarland SA. Establishing a Robust and Reliable Response from a Potent Osmium-Based Photosensitizer Via Lipid Nanoformulation †. Photochem Photobiol 2023; 99:751-760. [PMID: 36481983 PMCID: PMC10315168 DOI: 10.1111/php.13756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022]
Abstract
Osmium (Os) based photosensitizers (PSs) are a unique class of nontetrapyrrolic metal-containing PSs that absorb red light. We recently reported a highly potent Os(II) PS, rac-[Os(phen)2 (IP-4T)](Cl)2 , referred to as ML18J03 herein, with light EC50 values as low as 20 pm. ML18J03 also exhibits low dark toxicity and submicromolar light EC50 values in hypoxia in some cell lines. However, owing to its longer oligothiophene chain, ML18J03 is not completely water soluble and forms 1-2 μm sized aggregates in PBS containing 1% DMSO. This aggregation causes variability in PDT efficacy between assays and thus unreliable and irreproducible reports of in vitro activity. To that end, we utilized PEG-modified DPPC liposomes (138 nm diameter) and DSPE-mPEG2000 micelles (10.2 nm diameter) as lipid nanoformulation vehicles to mitigate aggregation of ML18J03 and found that the spectroscopic properties important to biological activity were maintained or improved. Importantly, the lipid formulations decreased the interassay variance between the EC50 values by almost 20-fold, with respect to the unformulated ML18J03 when using broadband visible light excitation (P = 0.0276). Herein, lipid formulations are presented as reliable platforms for more accurate in vitro photocytotoxicity quantification for PSs prone to aggregation (such as ML18J03) and will be useful for assessing their in vivo PDT effects.
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Affiliation(s)
- Houston D. Cole
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Menitte Eroy
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, United States
| | - John A. Roque
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Ge Shi
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Mina Guirguis
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, United States
| | - John Fakhry
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, United States
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Girgis Obaid
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, United States
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas 76019, United States
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Shah D, Eroy M, Fakhry J, Moffat A, Fritz K, Cole HD, Cameron CG, McFarland SA, Obaid G. Enabling In Vivo Optical Imaging of an Osmium Photosensitizer by Micellar Formulation. Pharmaceutics 2022; 14:2426. [PMID: 36365244 PMCID: PMC9693841 DOI: 10.3390/pharmaceutics14112426] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 07/30/2023] Open
Abstract
Osmium (Os)-based photosensitizers (PSs) exhibit unique broad, red-shifted absorption, favoring PDT activity at greater tissue depths. We recently reported on a potent Os(II) PS, rac-[Os(phen)2(IP-4T)](Cl)2 (ML18J03) with submicromolar hypoxia activity. ML18J03 exhibits a low luminescence quantum yield of 9.8 × 10-5 in PBS, which limits its capacity for in vivo luminescence imaging. We recently showed that formulating ML18J03 into 10.2 nm DSPE-mPEG2000 micelles (Mic-ML18J03) increases its luminescence quantum yield by two orders of magnitude. Here, we demonstrate that Mic-ML18J03 exhibits 47-fold improved accumulative luminescence signals in orthotopic AT-84 head and neck tumors. We show, for the first time, that micellar formulation provides up to 11.7-fold tumor selectivity for ML18J03. Furthermore, Mic-ML18J03 does not experience the concentration-dependent quenching observed with unformulated ML18J03 in PBS, and formulation reduces spectral shifting of the emission maxima during PDT (variance = 6.5 and 27.3, respectively). The Mic-ML18J03 formulation also increases the production of reactive molecular species 2-3-fold. These findings demonstrate that micellar formulation is a versatile and effective approach to enable in vivo luminescence imaging options for an otherwise quenched, yet promising, PS.
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Affiliation(s)
- Drashti Shah
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Menitte Eroy
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - John Fakhry
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Azophi Moffat
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Kevin Fritz
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Girgis Obaid
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
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Munegowda MA, Manalac A, Weersink M, Cole HD, McFarland SA, Lilge L. Ru(II) CONTAINING PHOTOSENSITIZERS FOR PHOTODYNAMIC THERAPY: A CRITIQUE ON REPORTING AND AN ATTEMPT TO COMPARE EFFICACY. Coord Chem Rev 2022; 470:214712. [PMID: 36686369 PMCID: PMC9850455 DOI: 10.1016/j.ccr.2022.214712] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ruthenium(II)-based coordination complexes have emerged as photosensitizers (PSs) for photodynamic therapy (PDT) in oncology as well as antimicrobial indications and have great potential. Their modular architectures that integrate multiple ligands can be exploited to tune cellular uptake and subcellular targeting, solubility, light absorption, and other photophysical properties. A wide range of Ru(II) containing compounds have been reported as PSs for PDT or as photochemotherapy (PCT) agents. Many studies employ a common scaffold that is subject to systematic variation in one or two ligands to elucidate the impact of these modifications on the photophysical and photobiological performance. Studies that probe the excited state energies and dynamics within these molecules are of fundamental interest and are used to design next-generation systems. However, a comparison of the PDT efficacy between Ru(II) containing PSs and 1st or 2nd generation PSs, already in clinical use or preclinical/clinical studies, is rare. Even comparisons between Ru(II) containing molecular structures are difficult, given the wide range of excitation wavelengths, power densities, and cell lines utilized. Despite this gap, PDT dose metrics quantifying a PS's efficacy are available to perform qualitative comparisons. Such models are independent of excitation wavelength and are based on common outcome parameters, such as the photon density absorbed by the Ru(II) compound to cause 50% cell kill (LD50) based on the previously established threshold model. In this focused photophysical review, we identified all published studies on Ru(II) containing PSs since 2005 that reported the required photophysical, light treatment, and in vitro outcome data to permit the application of the Photodynamic Threshold Model to quantify their potential efficacy. The resulting LD50 values range from less than 1013 to above 1020 [hν cm-3], indicating a wide range in PDT efficacy and required optical energy density for ultimate clinical translation.
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Affiliation(s)
| | - Angelica Manalac
- Princess Margaret Cancer Centre, University Health Network,
Toronto, Ontario, Canada
- Dept Medical Biophysics, University of Toronto, Toronto,
Ontario, Canada
| | - Madrigal Weersink
- Princess Margaret Cancer Centre, University Health Network,
Toronto, Ontario, Canada
| | - Houston D. Cole
- Dept of Chemistry and Biochemistry, The University of Texas
at Arlington, Arlington, Texas, USA
| | - Sherri A. McFarland
- Dept of Chemistry and Biochemistry, The University of Texas
at Arlington, Arlington, Texas, USA
| | - Lothar Lilge
- Princess Margaret Cancer Centre, University Health Network,
Toronto, Ontario, Canada
- Dept Medical Biophysics, University of Toronto, Toronto,
Ontario, Canada
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Handlovic TT, Wahab MF, Cole HD, Alatrash N, Ramasamy E, MacDonnell FM, McFarland SA, Armstrong DW. Insights into enantioselective separations of ionic metal complexes by sub/supercritical fluid chromatography. Anal Chim Acta 2022; 1228:340156. [PMID: 36126998 PMCID: PMC9504283 DOI: 10.1016/j.aca.2022.340156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/29/2022] [Accepted: 07/07/2022] [Indexed: 11/25/2022]
Abstract
Sub/supercritical fluid chromatography (SFC) is a green separation technique that has been used to separate a wide variety of compounds and is proven to be immensely useful for chiral separations. However, SFC is currently not thought to be applicable for ionic compounds due to their low solubility in CO2, even with additives and organic modifiers. Recently, a large amount of research has been centered on octahedral complexes of Ru(II) and Os(II) with bidentate polypyridyl ligands due to their ability to serve in cancer treatment and other biological activities. These compounds exist as the delta (Δ) and lambda (Λ) enantiomers. Previously, similar compounds have been enantiomerically separated using HPLC and capillary electrophoresis, but never with SFC. Cyclofructan-6 (CF6) derivatized with (R)-naphthyl ethyl (RN) groups has been proven to be an effective chiral stationary phase for these separations in HPLC. This column chemistry was expanded to SFC to provide the first chiral separation of a wide variety (23 complexes in total) of ionic octahedral polypyridyl complexes. Unexpected behavior for mixing methanol and acetonitrile as the organic modifier will be discussed, along with the effects of additives. Enantioselectivity on CF6-RN chemistry is shown to be dependent on the conjugation level and rigidity of the metal complexes. Mass transfer kinetic behavior is also shown, and high-efficiency baseline resolved rapid separations are shown for fast screening or quantitation of representative coordination complexes.
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Affiliation(s)
- Troy T Handlovic
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 76019, USA
| | - M Farooq Wahab
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 76019, USA
| | - Houston D Cole
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 76019, USA
| | - Nagham Alatrash
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 76019, USA
| | - Elamparuthi Ramasamy
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 76019, USA
| | | | - Sherri A McFarland
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 76019, USA
| | - Daniel W Armstrong
- Department of Chemistry and Biochemistry, University of Texas at Arlington, 76019, USA.
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9
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Roque Iii JA, Cole HD, Barrett PC, Lifshits LM, Hodges RO, Kim S, Deep G, Francés-Monerris A, Alberto ME, Cameron CG, McFarland SA. Intraligand Excited States Turn a Ruthenium Oligothiophene Complex into a Light-Triggered Ubertoxin with Anticancer Effects in Extreme Hypoxia. J Am Chem Soc 2022; 144:8317-8336. [PMID: 35482975 PMCID: PMC9098688 DOI: 10.1021/jacs.2c02475] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ru(II) complexes that undergo photosubstitution reactions from triplet metal-centered (3MC) excited states are of interest in photochemotherapy (PCT) due to their potential to produce cytotoxic effects in hypoxia. Dual-action systems that incorporate this stoichiometric mode to complement the oxygen-dependent photosensitization pathways that define photodynamic therapy (PDT) are poised to maintain antitumor activity regardless of the oxygenation status. Herein, we examine the way in which these two pathways influence photocytotoxicity in normoxia and in hypoxia using the [Ru(dmp)2(IP-nT)]2+ series (where dmp = 2,9-dimethyl-1,10-phenanthroline and IP-nT = imidazo[4,5-f][1,10]phenanthroline tethered to n = 0-4 thiophene rings) to switch the dominant excited state from the metal-based 3MC state in the case of Ru-phen-Ru-1T to the ligand-based 3ILCT state for Ru-3T and Ru-4T. Ru-phen-Ru-1T, having dominant 3MC states and the largest photosubstitution quantum yields, are inactive in both normoxia and hypoxia. Ru-3T and Ru-4T, with dominant 3IL/3ILCT states and long triplet lifetimes (τTA = 20-25 μs), have the poorest photosubstitution quantum yields, yet are extremely active. In the best instances, Ru-4T exhibit attomolar phototoxicity toward SKMEL28 cells in normoxia and picomolar in hypoxia, with phototherapeutic index values in normoxia of 105-1012 and 103-106 in hypoxia. While maximizing excited-state deactivation through photodissociative 3MC states did not result in bonafide dual-action PDT/PCT agents, the study has produced the most potent photosensitizer we know of to date. The extraordinary photosensitizing capacity of Ru-3T and Ru-4T may stem from a combination of very efficient 1O2 production and possibly complementary type I pathways via 3ILCT excited states.
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Affiliation(s)
- John A Roque Iii
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States.,Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Houston D Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Patrick C Barrett
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Liubov M Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Rachel O Hodges
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Susy Kim
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, North Carolina 27157, United States
| | - Gagan Deep
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, North Carolina 27157, United States
| | | | - Marta E Alberto
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Arcavacata di Rende 87036, Italy
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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10
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Chettri A, Cole HD, Roque JA, Schneider KRA, Yang T, Cameron CG, McFarland SA, Dietzek-Ivanšić B. Interaction with a Biomolecule Facilitates the Formation of the Function-Determining Long-Lived Triplet State in a Ruthenium Complex for Photodynamic Therapy. J Phys Chem A 2022; 126:1336-1344. [PMID: 35179905 PMCID: PMC8903189 DOI: 10.1021/acs.jpca.1c09968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
TLD1433 is the first ruthenium (Ru)-based photodynamic therapy (PDT) agent to advance to clinical trials and is currently in a phase II study for treating nonmuscle bladder cancer with PDT. Herein, we present a photophysical study of TLD1433 and its derivative TLD1633 using complex, biologically relevant solvents to elucidate the excited-state properties that are key for biological activity. The complexes incorporate an imidazo [4,5-f][1,10]phenanthroline (IP) ligand appended to α-ter- or quaterthiophene, respectively, where TLD1433 = [Ru(4,4'-dmb)2(IP-3T)]Cl2 and TLD1633 = [Ru(4,4'-dmb)2(IP-4T)]Cl2 (4,4'-dmb = 4,4'-dimethyl-2,2'-bipyridine; 3T = α-terthiophene; 4T = α-quaterthiophene). Time-resolved transient absorption experiments demonstrate that the excited-state dynamics of the complexes change upon interaction with biological macromolecules (e.g., DNA). In this case, the accessibility of the lowest-energy triplet intraligand charge-transfer (3ILCT) state (T1) is increased at the expense of a higher-lying 3ILCT state. We attribute this behavior to the increased rigidity of the ligand framework upon binding to DNA, which prolongs the lifetime of the T1 state. This lowest-lying state is primarily responsible for O2 sensitization and hence photoinduced cytotoxicity. Therefore, to gain a realistic picture of the excited-state kinetics that underlie the photoinduced function of the complexes, it is necessary to interrogate their photophysical dynamics in the presence of biological targets once they are known.
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Affiliation(s)
- Avinash Chettri
- Leibniz Institute of Photonic Technology Jena, Department Functional Interfaces, Albert-Einstein-Straße 9, 07745 Jena, Germany,Friedrich Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena, Germany
| | - Houston D. Cole
- The University of Texas at Arlington, Department of Chemistry and Biochemistry, Arlington, TX 76019, USA
| | - John A. Roque
- The University of Texas at Arlington, Department of Chemistry and Biochemistry, Arlington, TX 76019, USA,The University of North Carolina at Greensboro, Department of Chemistry and Biochemistry, Greensboro, NC 27402, USA
| | - Kilian R. A. Schneider
- Leibniz Institute of Photonic Technology Jena, Department Functional Interfaces, Albert-Einstein-Straße 9, 07745 Jena, Germany,Friedrich Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena, Germany
| | - Tingxiang Yang
- Leibniz Institute of Photonic Technology Jena, Department Functional Interfaces, Albert-Einstein-Straße 9, 07745 Jena, Germany,Friedrich Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena, Germany
| | - Colin G. Cameron
- The University of Texas at Arlington, Department of Chemistry and Biochemistry, Arlington, TX 76019, USA
| | - Sherri A. McFarland
- The University of Texas at Arlington, Department of Chemistry and Biochemistry, Arlington, TX 76019, USA
| | - Benjamin Dietzek-Ivanšić
- Leibniz Institute of Photonic Technology Jena, Department Functional Interfaces, Albert-Einstein-Straße 9, 07745 Jena, Germany,Friedrich Schiller University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena, Germany
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11
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Cole HD, Roque JA, Lifshits LM, Hodges R, Barrett PC, Havrylyuk D, Heidary D, Ramasamy E, Cameron CG, Glazer EC, McFarland SA. Fine-Feature Modifications to Strained Ruthenium Complexes Radically Alter Their Hypoxic Anticancer Activity †. Photochem Photobiol 2022; 98:73-84. [PMID: 33559191 PMCID: PMC8349932 DOI: 10.1111/php.13395] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 01/03/2023]
Abstract
In an earlier study of π-expansive ruthenium complexes for photodynamic and photochemo-therapies, it was shown that a pair of structural isomers differing only in the connection point of a naphthalene residue exhibited vastly different biological activity. These isomers are further explored in this paper through the activity of their functionalized derivatives. In normoxia, the inactive 2-NIP isomer (5) can be made as photocytotoxic as the active 1-NIP isomer (1) by functionalizing with methyl or methoxy groups, while methoxy variants of the 1-NIP isomer became inactive. In all cases, the singlet oxygen sensitization quantum yield was below 1%. Hypoxic photocytotoxicity was attenuated, with only three of the series showing any activity, notwithstanding the photodissociative ligands. The results here are consistent with the earlier findings in that seemingly minor structural modifications on the non-strained ligand can dramatically modulate the normoxic and hypoxic activity of these strained compounds and that these changes appear to exert a greater influence on photocytotoxicity than singlet oxygen sensitization or rates of photosubstitution in cell-free conditions would suggest.
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Affiliation(s)
- Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - John A. Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States,Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Liubov M. Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - Rachel Hodges
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Patrick C. Barrett
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Dmytro Havrylyuk
- Department of Chemistry, University of Kentucky, Lexington, KY, 76019-0065 United States, 40506-0055
| | - David Heidary
- Department of Chemistry, University of Kentucky, Lexington, KY, 76019-0065 United States, 40506-0055
| | - Elamparuthi Ramasamy
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States,Corresponding authors: C.G.C <>; E.C.G. <>; S.A.M. <>
| | - Edith C. Glazer
- Department of Chemistry, University of Kentucky, Lexington, KY, 76019-0065 United States, 40506-0055,Corresponding authors: C.G.C <>; E.C.G. <>; S.A.M. <>
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States,Corresponding authors: C.G.C <>; E.C.G. <>; S.A.M. <>
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12
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Cole HD, Roque JA, Shi G, Lifshits LM, Ramasamy E, Barrett PC, Hodges RO, Cameron CG, McFarland SA. Anticancer Agent with Inexplicable Potency in Extreme Hypoxia: Characterizing a Light-Triggered Ruthenium Ubertoxin. J Am Chem Soc 2021; 144:9543-9547. [PMID: 34882381 DOI: 10.1021/jacs.1c09010] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Tumor hypoxia renders treatments ineffective that are directly (e.g., radiotherapy and photodynamic therapy) or indirectly (e.g., chemotherapy) dependent on tumor oxygenation. This study introduces a ruthenium compound as a light-responsive anticancer agent that is water-soluble, has minimal dark cytotoxicity, is active at concentrations as low as 170 pM in ∼18.5% O2 normoxia and near 10 nM in 1% O2 hypoxia, and exhibits phototherapeutic indices as large as >500,000 in normoxia and >5,800 in 1% O2 hypoxia using broadband visible and monochromatic blue light treatments. These are the largest values reported to date for any compound class. We highlight the response in four different cell lines to improve rigor and reproducibility in the identification of promising clinical candidates.
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Affiliation(s)
- Houston D Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - John A Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States.,Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Ge Shi
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Liubov M Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Elamparuthi Ramasamy
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Patrick C Barrett
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Rachel O Hodges
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019-0065, United States
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13
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Chettri A, Schneider KRA, Cole HD, Roque JA, Cameron CG, McFarland SA, Dietzek B. String-Attached Oligothiophene Substituents Determine the Fate of Excited States in Ruthenium Complexes for Photodynamic Therapy. J Phys Chem A 2021; 125:6985-6994. [PMID: 34370485 DOI: 10.1021/acs.jpca.1c04900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We explore the photophysical properties of a family of Ru(II) complexes, Ru-ip-nT, designed as photosensitizers (PSs) for photodynamic therapy (PDT). The complexes incorporate a 1H-imidazo[4,5-f][1,10]-phenanthroline (ip) ligand appended to one or more thiophene rings. One of the complexes studied herein, Ru-ip-3T (known as TLD1433), is currently in phase II human clinical trials for treating bladder cancer by PDT. The potent photocytotoxicity of Ru-ip-3T is attributed to a long-lived intraligand charge-transfer triplet state. The accessibility of this state changes upon varying the length (n) of the oligothiophene substituent. In this paper, we highlight the impact of n on the ultrafast photoinduced dynamics in Ru-ip-nT, leading to the formation of the function-determining long-lived state. Femtosecond time-resolved transient absorption combined with resonance Raman data was used to map the excited-state relaxation processes from the Franck-Condon point of absorption to the formation of the lowest-energy triplet excited state, which is a triplet metal-to-ligand charge-transfer excited state for Ru-ip-0T-1T and an oligothienyl-localized triplet intraligand charge-transfer excited state for Ru-ip-2T-4T. We establish the structure-activity relationships with regard to changes in the excited-state dynamics as a function of thiophene chain length, which alters the photophysics of the complexes and presumably impacts the photocytotoxicity of these PSs.
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Affiliation(s)
- Avinash Chettri
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Kilian R A Schneider
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Houston D Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - John A Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States.,Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, United States
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Benjamin Dietzek
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany.,Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
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14
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Chettri A, Roque JA, Schneider KRA, Cole HD, Cameron CG, McFarland SA, Dietzek B. It Takes Three to Tango - the length of the oligothiophene determines the nature of the long-lived excited state and the resulting photocytotoxicity of a Ru(II) photodrug. CHEMPHOTOCHEM 2021; 5:421-425. [PMID: 34337147 PMCID: PMC8323708 DOI: 10.1002/cptc.202000283] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Indexed: 02/06/2023]
Abstract
TLD1433 is the first Ru(II) complex to be tested as a photodynamic therapy agent in a clinical trial. In this contribution we study TLD1433 in the context of structurally-related Ru(II)-imidozo[4,5-f][1,10]phenanthroline (ip) complexes appended with thiophene rings to decipher the unique photophysical properties which are associated with increasing oligothiophene chain length. Substitution of the ip ligand with ter- or quaterthiophene changes the nature of the long-lived triplet state from metal-to-ligand charge-transfer to 3ππ* character. The addition of the third thiophene thus presents a critical juncture which not only determines the photophysics of the complex but most importantly its capacity for 1O2 generation and hence the potential of the complex to be used as a photocytotoxic agent. ENTRY FOR THE TABLE OF CONTENTS A low-lying triplet intraligand state (3IL) determines the properties of the long-lived excited states in a series of Ru(II) complexes. The 3IL state can be accessed by increasing the length of an oligothiophene chain. The 3IL state is extremely efficient at generating 1O2 and thus enhances the potency of the complexes as PDT agents.
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Affiliation(s)
- Avinash Chettri
- Department Functional Interfaces Department, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
- Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - John A. Roque
- Department of Chemistry and Biochemistry, The University of Texas Arlington, Arlington, TX 76019, USA
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, USA
| | - Kilian R. A. Schneider
- Department Functional Interfaces Department, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
- Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas Arlington, Arlington, TX 76019, USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas Arlington, Arlington, TX 76019, USA
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas Arlington, Arlington, TX 76019, USA
| | - Benjamin Dietzek
- Department Functional Interfaces Department, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
- Institute of Physical Chemistry, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
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15
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Bataglioli JC, Gomes LMF, Maunoir C, Smith JR, Cole HD, McCain J, Sainuddin T, Cameron CG, McFarland SA, Storr T. Modification of amyloid-beta peptide aggregation via photoactivation of strained Ru(ii) polypyridyl complexes. Chem Sci 2021; 12:7510-7520. [PMID: 34163842 PMCID: PMC8171320 DOI: 10.1039/d1sc00004g] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 04/19/2021] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by progressive and irreversible damage to the brain. One of the hallmarks of the disease is the presence of both soluble and insoluble aggregates of the amyloid beta (Aβ) peptide in the brain, and these aggregates are considered central to disease progression. Thus, the development of small molecules capable of modulating Aβ peptide aggregation may provide critical insight into the pathophysiology of AD. In this work we investigate how photoactivation of three distorted Ru(ii) polypyridyl complexes (Ru1-3) alters the aggregation profile of the Aβ peptide. Photoactivation of Ru1-3 results in the loss of a 6,6'-dimethyl-2,2'-bipyridyl (6,6'-dmb) ligand, affording cis-exchangeable coordination sites for binding to the Aβ peptide. Both Ru1 and Ru2 contain an extended planar imidazo[4,5-f][1,10]phenanthroline ligand, as compared to a 2,2'-bipyridine ligand for Ru3, and we show that the presence of the phenanthroline ligand promotes covalent binding to Aβ peptide His residues, and in addition, leads to a pronounced effect on peptide aggregation immediately after photoactivation. Interestingly, all three complexes resulted in a similar aggregate size distribution at 24 h, forming insoluble amorphous aggregates as compared to significant fibril formation for peptide alone. Photoactivation of Ru1-3 in the presence of pre-formed Aβ1-42 fibrils results in a change to amorphous aggregate morphology, with Ru1 and Ru2 forming large amorphous aggregates immediately after activation. Our results show that photoactivation of Ru1-3 in the presence of either monomeric or fibrillar Aβ1-42 results in the formation of large amorphous aggregates as a common endpoint, with Ru complexes incorporating the extended phenanthroline ligand accelerating this process and thereby limiting the formation of oligomeric species in the initial stages of the aggregation process that are reported to show considerable toxicity.
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Affiliation(s)
| | - Luiza M F Gomes
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
| | - Camille Maunoir
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
| | - Jason R Smith
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
| | - Houston D Cole
- Department of Chemistry and Biochemistry, University of Texas Arlington Texas USA 76019
| | - Julia McCain
- Department of Chemistry, Acadia University Wolfville Nova Scotia Canada B4P 2R6
| | - Tariq Sainuddin
- Department of Chemistry, Acadia University Wolfville Nova Scotia Canada B4P 2R6
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, University of Texas Arlington Texas USA 76019
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, University of Texas Arlington Texas USA 76019
| | - Tim Storr
- Department of Chemistry, Simon Fraser University BC Canada V5A-1S6
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16
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Qu F, Lamb RW, Cameron CG, Park S, Oladipupo O, Gray JL, Xu Y, Cole HD, Bonizzoni M, Kim Y, McFarland SA, Webster CE, Papish ET. Singlet Oxygen Formation vs Photodissociation for Light-Responsive Protic Ruthenium Anticancer Compounds: The Oxygenated Substituent Determines Which Pathway Dominates. Inorg Chem 2021; 60:2138-2148. [PMID: 33534562 DOI: 10.1021/acs.inorgchem.0c02027] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ruthenium complexes bearing protic diimine ligands are cytotoxic to certain cancer cells upon irradiation with blue light. Previously reported complexes of the type [(N,N)2Ru(6,6'-dhbp)]Cl2 with 6,6'-dhbp = 6,6'-dihydroxybipyridine and N,N = 2,2'-bipyridine (bipy) (1A), 1,10-phenanthroline (phen) (2A), and 2,3-dihydro-[1,4]dioxino[2,3-f][1,10]phenanthroline (dop) (3A) show EC50 values as low as 4 μM (for 3A) vs breast cancer cells upon blue light irradiation ( Inorg. Chem. 2017, 56, 7519). Herein, subscript A denotes the acidic form of the complex bearing OH groups, and B denotes the basic form bearing O- groups. This photocytotoxicity was originally attributed to photodissociation, but recent results suggest that singlet oxygen formation is a more plausible cause of photocytotoxicity. In particular, bulky methoxy substituents enhance photodissociation but these complexes are nontoxic ( Dalton Trans 2018, 47, 15685). Cellular studies are presented herein that show the formation of reactive oxygen species (ROS) and apoptosis indicators upon treatment of cells with complex 3A and blue light. Singlet oxygen sensor green (SOSG) shows the formation of 1O2 in cell culture for cells treated with 3A and blue light. At physiological pH, complexes 1A-3A are deprotonated to form 1B-3B in situ. Quantum yields for 1O2 (ϕΔ) are 0.87 and 0.48 for 2B and 3B, respectively, and these are an order of magnitude higher than the quantum yields for 2A and 3A. The values for ϕΔ show an increase with 6,6'-dhbp derived substituents as follows: OMe < OH < O-. TD-DFT studies show that the presence of a low lying triplet metal-centered (3MC) state favors photodissociation and disfavors 1O2 formation for 2A and 3A (OH groups). However, upon deprotonation (O- groups), the 3MLCT state is accessible and can readily lead to 1O2 formation, but the dissociative 3MC state is energetically inaccessible. The changes to the energy of the 3MLCT state upon deprotonation have been confirmed by steady state luminescence experiments on 1A-3A and their basic analogs, 1B-3B. This energy landscape favors 1O2 formation for 2B and 3B and leads to enhanced toxicity for these complexes under physiological conditions. The ability to convert readily from OH to O- groups allowed us to investigate an electronic change that is not accompanied by steric changes in this fundamental study.
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Affiliation(s)
- Fengrui Qu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Robert W Lamb
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, Texas 76019, United States
| | - Seungjo Park
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Olaitan Oladipupo
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Jessica L Gray
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Yifei Xu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Houston D Cole
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, Texas 76019, United States
| | - Marco Bonizzoni
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Yonghyun Kim
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, United States
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, Texas 76019, United States
| | - Charles Edwin Webster
- Department of Chemistry, Mississippi State University, Mississippi State, Mississippi 39762, United States
| | - Elizabeth T Papish
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, Alabama 35487, United States
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17
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Konda P, Lifshits LM, Roque JA, Cole HD, Cameron CG, McFarland SA, Gujar S. Discovery of immunogenic cell death-inducing ruthenium-based photosensitizers for anticancer photodynamic therapy. Oncoimmunology 2020; 10:1863626. [PMID: 33457082 PMCID: PMC7781847 DOI: 10.1080/2162402x.2020.1863626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 12/08/2020] [Indexed: 11/17/2022] Open
Abstract
We report a new class of ruthenium (Ru)-based photosensitizers that induce potent cytotoxicity in melanoma cells following activation with NIR light. In addition to the direct cytotoxic effect, this Ru-based photodynamic therapy induces immunogenic cell death in melanoma cells that can be therapeutically exploited to establish protective antitumor immunity.
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Affiliation(s)
- Prathyusha Konda
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada
| | - Liubov M. Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - John A. Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, USA
| | - Shashi Gujar
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Canada
- Department of Pathology, Dalhousie University, Halifax, Canada
- Department of Biology, Dalhousie University, Halifax, Canada
- Beatrice Hunter Cancer Research Institute, Dalhousie University, Halifax, Canada
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18
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Lifshits LM, Roque JA, Cole HD, Thummel RP, Cameron CG, McFarland SA. NIR-Absorbing Ru II Complexes Containing α-Oligothiophenes for Applications in Photodynamic Therapy. Chembiochem 2020; 21:3594-3607. [PMID: 32761725 PMCID: PMC7736147 DOI: 10.1002/cbic.202000419] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/03/2020] [Indexed: 12/12/2022]
Abstract
The design of near-infrared (NIR)-active photosensitizers (PSs) for light-based cancer treatments such as photodynamic therapy (PDT) has been a challenge. While several NIR-RuII scaffolds have been reported, this approach has not been proven in cells. This is the first report of NIR-RuII PSs that are phototoxic to cancer cells, including highly pigmented B16F10 melanoma cells. The PS family incorporated a bis(1,8-naphthyridine)-based ligand (tpbn), a bidentate thiophene-based ligand (nT; n=0-4), and a monodentate 4-picoline ligand (4-pic). All compounds absorbed light >800 nm with maxima near 730 nm. Transient absorption (TA) measurements indicated that n=4 thiophene rings (4T) positioned the PDT-active triplet intraligand charge transfer (3 ILCT) excited state in energetic proximity to the lowest-lying triplet metal-to-ligand charge transfer (3 MLCT). 4T had low-micromolar phototoxicity with PIvis and PI733nm values as large as 90 and 12, respectively. Spectroscopic studies suggested that the longer-lived (τTA =3-6 μs) 3 ILCT state was accessible from the 3 MLCT state, but energetically uphill in the overall photophysics. The study highlights that phototoxic effects can be achieved with NIR-absorbing RuII PSs as long as the reactive 3 ILCT states are energetically accessible from the low-energy 3 MLCT states. It also demonstrates that tissue-penetrating NIR light can be used to activate the PSs in highly pigmented cells where melanin attenuates shorter wavelengths of light.
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Affiliation(s)
- Liubov M. Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - John A. Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402, USA
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - Randolph P. Thummel
- Department of Chemistry, University of Houston, 112 Fleming Building, Houston, Texas, 77204-5003, USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019-0065 United States
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Schneider KRA, Chettri A, Cole HD, Reglinski K, Brückmann J, Roque JA, Stumper A, Nauroozi D, Schmid S, Lagerholm CB, Rau S, Bäuerle P, Eggeling C, Cameron CG, McFarland SA, Dietzek B. Intracellular Photophysics of an Osmium Complex bearing an Oligothiophene Extended Ligand. Chemistry 2020; 26:14844-14851. [PMID: 32761643 PMCID: PMC7704931 DOI: 10.1002/chem.202002667] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/26/2020] [Indexed: 12/27/2022]
Abstract
This contribution describes the excited-state properties of an Osmium-complex when taken up into human cells. The complex 1 [Os(bpy)2 (IP-4T)](PF6 )2 with bpy=2,2'-bipyridine and IP-4T=2-{5'-[3',4'-diethyl-(2,2'-bithien-5-yl)]-3,4-diethyl-2,2'-bithiophene}imidazo[4,5-f][1,10]phenanthroline) can be discussed as a candidate for photodynamic therapy in the biological red/NIR window. The complex is taken up by MCF7 cells and localizes rather homogeneously within in the cytoplasm. To detail the sub-ns photophysics of 1, comparative transient absorption measurements were carried out in different solvents to derive a model of the photoinduced processes. Key to rationalize the excited-state relaxation is a long-lived 3 ILCT state associated with the oligothiophene chain. This model was then tested with the complex internalized into MCF7 cells, since the intracellular environment has long been suspected to take big influence on the excited state properties. In our study of 1 in cells, we were able to show that, though the overall model remained the same, the excited-state dynamics are affected strongly by the intracellular environment. Our study represents the first in depth correlation towards ex-vivo and in vivo ultrafast spectroscopy for a possible photodrug.
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Affiliation(s)
- Kilian R. A. Schneider
- Department Functional Interfaces (K.R.A.S., A.C., B.D.)Department Biophysical Imaging (K.R., C.E.)Leibniz Institute of Photonic Technology (IPHT) e. V.Albert-Einstein-Straße 907745JenaGermany
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich-Schiller-University JenaHelmholtzweg 407743JenaGermany
| | - Avinash Chettri
- Department Functional Interfaces (K.R.A.S., A.C., B.D.)Department Biophysical Imaging (K.R., C.E.)Leibniz Institute of Photonic Technology (IPHT) e. V.Albert-Einstein-Straße 907745JenaGermany
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich-Schiller-University JenaHelmholtzweg 407743JenaGermany
| | - Houston D. Cole
- Department of Chemistry and BiochemistryThe University of Texas at ArlingtonArlingtonTX76019-0065USA
| | - Katharina Reglinski
- Department Functional Interfaces (K.R.A.S., A.C., B.D.)Department Biophysical Imaging (K.R., C.E.)Leibniz Institute of Photonic Technology (IPHT) e. V.Albert-Einstein-Straße 907745JenaGermany
- Institute of Applied Optic and BiophysicsFriedrich-Schiller University JenaMax-Wien-Platz 107743JenaGermany
- University Hospital JenaBachstraße 1807743JenaGermany
| | - Jannik Brückmann
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - John A. Roque
- Department of Chemistry and BiochemistryThe University of Texas at ArlingtonArlingtonTX76019-0065USA
- Department of Chemistry and BiochemistryThe University of North Carolina at GreensboroGreensboroNorth Carolina27402USA
| | - Anne Stumper
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Djawed Nauroozi
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Sylvia Schmid
- Institute of Organic Chemistry II and Advanced MaterialsUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | | | - Sven Rau
- Institute of Inorganic Chemistry IUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Peter Bäuerle
- Institute of Organic Chemistry II and Advanced MaterialsUlm UniversityAlbert-Einstein-Allee 1189081UlmGermany
| | - Christian Eggeling
- Department Functional Interfaces (K.R.A.S., A.C., B.D.)Department Biophysical Imaging (K.R., C.E.)Leibniz Institute of Photonic Technology (IPHT) e. V.Albert-Einstein-Straße 907745JenaGermany
- Institute of Applied Optic and BiophysicsFriedrich-Schiller University JenaMax-Wien-Platz 107743JenaGermany
- <MRC Human Immunology Unit & Wolfson Imaging Center OxfordHeadley WayOxfordOX3 9DSUK
| | - Colin G. Cameron
- Department of Chemistry and BiochemistryThe University of Texas at ArlingtonArlingtonTX76019-0065USA
| | - Sherri A. McFarland
- Department of Chemistry and BiochemistryThe University of Texas at ArlingtonArlingtonTX76019-0065USA
| | - Benjamin Dietzek
- Department Functional Interfaces (K.R.A.S., A.C., B.D.)Department Biophysical Imaging (K.R., C.E.)Leibniz Institute of Photonic Technology (IPHT) e. V.Albert-Einstein-Straße 907745JenaGermany
- Institute of Physical Chemistry and Abbe Center of PhotonicsFriedrich-Schiller-University JenaHelmholtzweg 407743JenaGermany
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Roque JA, Barrett PC, Cole HD, Lifshits LM, Bradner E, Shi G, von Dohlen D, Kim S, Russo N, Deep G, Cameron CG, Alberto ME, McFarland SA. Os(II) Oligothienyl Complexes as a Hypoxia-Active Photosensitizer Class for Photodynamic Therapy. Inorg Chem 2020; 59:16341-16360. [PMID: 33126792 PMCID: PMC7669743 DOI: 10.1021/acs.inorgchem.0c02137] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hypoxia presents a challenge to anticancer therapy, reducing the efficacy of many available treatments. Photodynamic therapy is particularly susceptible to hypoxia, given that its mechanism relies on oxygen. Herein, we introduce two new osmium-based polypyridyl photosensitizers that are active in hypoxia. The lead compounds emerged from a systematic study of two Os(II) polypyridyl families derived from 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (dmb) as coligands combined with imidazo[4,5-f][1,10]phenanthroline ligands tethered to n = 0-4 thiophenes (IP-nT). The compounds were characterized and investigated for their spectroscopic and (photo)biological activities. The two hypoxia-active Os(II) photosensitizers had n = 4 thiophenes, with the bpy analogue 1-4T being the most potent. In normoxia, 1-4T had low nanomolar activity (half-maximal effective concentration (EC50) = 1-13 nM) with phototherapeutic indices (PI) ranging from 5500 to 55 000 with red and visible light, respectively. A sub-micromolar potency was maintained even in hypoxia (1% O2), with light EC50 and PI values of 732-812 nM and 68-76, respectively -currently among the largest PIs for hypoxic photoactivity. This high degree of activity coincided with a low-energy, long-lived (0.98-3.6 μs) mixed-character intraligand charge-transfer (3ILCT)/ligand-to-ligand charge-transfer (3LLCT) state only accessible in quaterthiophene complexes 1-4T and 2-4T. The coligand identity strongly influenced the photophysical and photobiological results in this study, whereby the bpy coligand led to longer lifetimes (3.6 μs) and more potent photo-cytotoxicity relative to those of dmb. The unactivated compounds were relatively nontoxic both in vitro and in vivo. The maximum tolerated dose for 1-4T and 2-4T in mice was greater than or equal to 200 mg kg-1, an excellent starting point for future in vivo validation.
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Affiliation(s)
- John A. Roque
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina, 27402 USA
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019 USA
| | - Patrick C. Barrett
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina, 27402 USA
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019 USA
| | - Liubov M. Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019 USA
| | - Evan Bradner
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina, 27402 USA
| | - Ge Shi
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia B3H 1×5, Canada
| | - David von Dohlen
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina, 27402 USA
| | - Susy Kim
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, NC, 27157 USA
| | - Nino Russo
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Arcavacata di Rende, 87036 Italy
| | - Gagan Deep
- Department of Cancer Biology, Wake Forest School of Medicine, Winston Salem, NC, 27157 USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019 USA
| | - Marta E. Alberto
- Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Arcavacata di Rende, 87036 Italy
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas, 76019 USA
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Roque JA, Barrett PC, Cole HD, Lifshits LM, Shi G, Monro S, von Dohlen D, Kim S, Russo N, Deep G, Cameron CG, Alberto ME, McFarland SA. Breaking the barrier: an osmium photosensitizer with unprecedented hypoxic phototoxicity for real world photodynamic therapy. Chem Sci 2020; 11:9784-9806. [PMID: 33738085 PMCID: PMC7953430 DOI: 10.1039/d0sc03008b] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/03/2020] [Indexed: 12/15/2022] Open
Abstract
Hypoxia presents a two-fold challenge in the treatment of cancer, as low oxygen conditions induce biological changes that make malignant tissues simultaneously more aggressive and less susceptible to standard chemotherapy. This paper reports the first metal-based photosensitizer that approaches the ideal properties for a phototherapy agent. The Os(phen)2-based scaffold was combined with a series of IP-nT ligands, where phen = 1,10-phenanthroline and IP-nT = imidazo[4,5-f][1,10]phenanthroline tethered to n = 0-4 thiophene rings. Os-4T (n = 4) emerged as the most promising complex in the series, with picomolar activity and a phototherapeutic index (PI) exceeding 106 in normoxia. The photosensitizer exhibited an unprecedented PI > 90 (EC50 = 0.651 μM) in hypoxia (1% O2) with visible and green light, and a PI > 70 with red light. Os-4T was also active with 733 nm near-infrared light (EC50 = 0.803 μM, PI = 77) under normoxia. Both computation and spectroscopic studies confirmed a switch in the nature of the lowest-lying triplet excited state from triplet metal-to-ligand charge transfer (3MLCT) to intraligand charge transfer (3ILCT) at n = 3, with a lower energy and longer lifetime for n = 4. All compounds in the series were relatively nontoxic in the dark but became increasingly phototoxic with additional thiophenes. These normoxic and hypoxic activities are the largest reported to date, demonstrating the utility of osmium for phototherapy applications. Moreover, Os-4T had a maximum tolerated dose (MTD) in mice that was >200 mg kg-1, which positions this photosensitizer as an excellent candidate for in vivo applications.
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Affiliation(s)
- John A Roque
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina , 27402 USA
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , Arlington , Texas , 76019 USA . ;
| | - Patrick C Barrett
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina , 27402 USA
| | - Houston D Cole
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , Arlington , Texas , 76019 USA . ;
| | - Liubov M Lifshits
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , Arlington , Texas , 76019 USA . ;
| | - Ge Shi
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia , B4P 2R6 Canada
| | - Susan Monro
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia , B4P 2R6 Canada
| | - David von Dohlen
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina , 27402 USA
| | - Susy Kim
- Department of Cancer Biology , Wake Forest School of Medicine , Winston Salem , NC , 27157, USA
| | - Nino Russo
- Dipartimento di Chimica e Tecnologie Chimiche , Università della Calabria , Arcavacata di Rende , 87036 Italy .
| | - Gagan Deep
- Department of Cancer Biology , Wake Forest School of Medicine , Winston Salem , NC , 27157, USA
| | - Colin G Cameron
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina , 27402 USA
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , Arlington , Texas , 76019 USA . ;
| | - Marta E Alberto
- Dipartimento di Chimica e Tecnologie Chimiche , Università della Calabria , Arcavacata di Rende , 87036 Italy .
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro , North Carolina , 27402 USA
- Department of Chemistry and Biochemistry , The University of Texas at Arlington , Arlington , Texas , 76019 USA . ;
- Department of Chemistry , Acadia University , Wolfville , Nova Scotia , B4P 2R6 Canada
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22
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Lifshits LM, Roque Iii JA, Konda P, Monro S, Cole HD, von Dohlen D, Kim S, Deep G, Thummel RP, Cameron CG, Gujar S, McFarland SA. Near-infrared absorbing Ru(ii) complexes act as immunoprotective photodynamic therapy (PDT) agents against aggressive melanoma. Chem Sci 2020; 11:11740-11762. [PMID: 33976756 PMCID: PMC8108386 DOI: 10.1039/d0sc03875j] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/04/2020] [Indexed: 12/15/2022] Open
Abstract
Mounting evidence over the past 20 years suggests that photodynamic therapy (PDT), an anticancer modality known mostly as a local treatment, has the capacity to invoke a systemic antitumor immune response, leading to protection against tumor recurrence. For aggressive cancers such as melanoma, where chemotherapy and radiotherapy are ineffective, immunomodulating PDT as an adjuvant to surgery is of interest. Towards the development of specialized photosensitizers (PSs) for treating pigmented melanomas, nine new near-infrared (NIR) absorbing PSs based on a Ru(ii) tris-heteroleptic scaffold [Ru(NNN)(NN)(L)]Cln, were explored. Compounds 2, 6, and 9 exhibited high potency toward melanoma cells, with visible EC50 values as low as 0.292–0.602 μM and PIs as high as 156–360. Single-micromolar phototoxicity was obtained with NIR-light (733 nm) with PIs up to 71. The common feature of these lead NIR PSs was an accessible low-energy triplet intraligand (3IL) excited state for high singlet oxygen (1O2) quantum yields (69–93%), which was only possible when the photosensitizing 3IL states were lower in energy than the lowest triplet metal-to-ligand charge transfer (3MLCT) excited states that typically govern Ru(ii) polypyridyl photophysics. PDT treatment with 2 elicited a pro-inflammatory response alongside immunogenic cell death in mouse B16F10 melanoma cells and proved safe for in vivo administration (maximum tolerated dose = 50 mg kg−1). Female and male mice vaccinated with B16F10 cells that were PDT-treated with 2 and challenged with live B16F10 cells exhibited 80 and 55% protection from tumor growth, respectively, leading to significantly improved survival and excellent hazard ratios of ≤0.2. Ru(ii) photosensitizers (PSs) destroy aggressive melanoma cells, triggering an immune response that leads to protection against tumor challenge and mouse survival.![]()
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Affiliation(s)
- Liubov M Lifshits
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
| | - John A Roque Iii
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA .,Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro Greensboro North Carolina 27402 USA
| | - Prathyusha Konda
- Department of Microbiology and Immunology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada
| | - Susan Monro
- Department of Chemistry, Acadia University Wolfville Nova Scotia B4P 2R6 Canada
| | - Houston D Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
| | - David von Dohlen
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro Greensboro North Carolina 27402 USA
| | - Susy Kim
- Department of Cancer Biology, Wake Forest School of Medicine Winston Salem NC 27157 USA
| | - Gagan Deep
- Department of Cancer Biology, Wake Forest School of Medicine Winston Salem NC 27157 USA
| | - Randolph P Thummel
- Department of Chemistry, University of Houston 112 Fleming Building Houston Texas 77204-5003 USA
| | - Colin G Cameron
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
| | - Shashi Gujar
- Department of Microbiology and Immunology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada .,Department of Pathology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada.,Department of Biology, Dalhousie University Halifax Nova Scotia B3H 1X5 Canada.,Beatrice Hunter Cancer Research Institute Halifax Nova Scotia B3H 4R2 Canada
| | - Sherri A McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington Arlington Texas 76019-0065 USA
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Chamberlain S, Cole HD, Roque J, Bellnier D, McFarland SA, Shafirstein G. TLD1433-Mediated Photodynamic Therapy with an Optical Surface Applicator in the Treatment of Lung Cancer Cells In Vitro. Pharmaceuticals (Basel) 2020; 13:E137. [PMID: 32605213 PMCID: PMC7407920 DOI: 10.3390/ph13070137] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 11/16/2022] Open
Abstract
Intra-operative photodynamic therapy (IO-PDT) in combination with surgery for the treatment of non-small cell lung cancer and malignant pleural mesothelioma has shown promise in improving overall survival in patients. Here, we developed a PDT platform consisting of a ruthenium-based photosensitizer (TLD1433) activated by an optical surface applicator (OSA) for the management of residual disease. Human lung adenocarcinoma (A549) cell viability was assessed after treatment with TLD1433-mediated PDT illuminated with either 532- or 630-nm light with a micro-lens laser fiber. This TLD1433-mediated PDT induced an EC50 of 1.98 μM (J/cm2) and 4807 μM (J/cm2) for green and red light, respectively. Cells were then treated with 10 µM TLD1433 in a 96-well plate with the OSA using two 2-cm radial diffusers, each transmitted 532 nm light at 50 mW/cm for 278 s. Monte Carlo simulations of the surface light propagation from the OSA computed light fluence (J/cm2) and irradiance (mW/cm2) distribution. In regions where 100% loss in cell viability was measured, the simulations suggest that >20 J/cm2 of 532 nm was delivered. Our studies indicate that TLD1433-mediated PDT with the OSA and light simulations have the potential to become a platform for treatment planning for IO-PDT.
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Affiliation(s)
- Sarah Chamberlain
- Department of Cell Stress Biology, Photodynamic Therapy Center, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA; (S.C.); (D.B.)
| | - Houston D. Cole
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065, USA; (H.D.C.); (J.R.III)
| | - John Roque
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065, USA; (H.D.C.); (J.R.III)
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - David Bellnier
- Department of Cell Stress Biology, Photodynamic Therapy Center, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA; (S.C.); (D.B.)
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065, USA; (H.D.C.); (J.R.III)
- Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, NC 27402-6170, USA
| | - Gal Shafirstein
- Department of Cell Stress Biology, Photodynamic Therapy Center, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA; (S.C.); (D.B.)
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Weinhofer AM, Cole HD, Mitchell BA, Ritz AJ, Vogt DB, Rabinovitch JE, Goess BC, Goforth SK. Ruthenium-catalyzed oxidation of silyl ethers to silyl esters. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2019.05.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
Incubation studies involving rabbit and piglet small intestinal mucosal components and Escherichia coli and Vibrio cholerae enterotoxins were conducted at 37 and 4 degrees C. Mucosal homogenate cytosol from rabbits did not significantly alter the reactivities of either cholera enterotoxin (CT) or E. coli labile enterotoxin (LT). However, mucosal homogenate cytosol from piglets was capable of neutralizing LT, though it had no effect on E. coli stable enterotoxin. LT became bound to piglet and rabbit microvillous membranes at 4 degrees C in the presence of a protective protein. In rabbits, the binding of LT was not dependent upon an intact glycocalyx or free unbound CT-receptors, although some binding was apparently associated with the glycocalyx and CT-receptors. These results indicated the presence of two different LT-receptors in microvillous membranes one being associated with the membrane proper and the other with the glycocalyx. Stable enterotoxin did not bind to in vitro preparations of piglet mucosal components, which is evidence for a different mechanism for inducing intestinal secretion.
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Scott WN, Landez JH, Cole HD. Effects of boranes upon tissues of the rat. I. Aspartate aminotransferase and lactic dehydrogenase. Proc Soc Exp Biol Med 1970; 134:348-52. [PMID: 5423524 DOI: 10.3181/00379727-134-34791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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