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Profitt LA, Baxter RHG, Valentine AM. Superstoichiometric Binding of the Anticancer Agent Titanocene Dichloride by Human Serum Transferrin and the Accompanying Lobe Closure. Biochemistry 2022; 61:795-803. [PMID: 35373558 DOI: 10.1021/acs.biochem.1c00813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Titanocene dichloride (TDC) is an anticancer agent that delivers Ti(IV) into each of the two Fe(III) binding sites of bilobal human serum transferrin (Tf). This protein has been implicated in the selective transport of Ti(IV) to cells. How Ti(IV) might be released from the Tf Fe(III) binding site has remained a question, and crystal structures have raised issues about lobe occupancy and lobe closure in Ti(IV)-loaded Tf, compared with the Fe(III)-loaded form. Here, inductively coupled plasma optical emission spectroscopy reveals that Tf can stabilize toward hydrolytic precipitation more than 2 equiv of Ti, implying superstoichiometric binding beyond the two Fe(III) binding sites. Further studies support the inability of TDC to induce a complete lobe closure of Tf. Fluorescence data for TDC binding at low equivalents of TDC support an initial protein conformational change and lobe closure upon Ti binding, whereas data at higher equivalents support an open lobe configuration. Spectroscopic titration reveals less intense protein-metal electronic transitions as TDC equivalents are increased. Denaturing urea-PAGE gels and small angle X-ray scattering studies support an open lobe conformation. The concentrations of bicarbonate used in some earlier studies are demonstrated here to cause a pH change over time, which may contribute to variation in the apparent molar absorptivity associated with Ti(IV) binding in the Fe binding site. Finally, Fe(III)-bound holo-Tf still stabilizes TDC toward hydrolytic precipitation, a finding that underscores the importance of the interactions of Tf and TDC outside the Fe(III) binding site and suggests possible new pathways of Ti introduction to cells.
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Affiliation(s)
- Lauren A Profitt
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Richard H G Baxter
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Ann M Valentine
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
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2
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Paredes A, Loh BM, Peduzzi OM, Reig AJ, Buettner KM. DNA Cleavage by a De Novo Designed Protein-Titanium Complex. Inorg Chem 2020; 59:11248-11252. [PMID: 32799485 DOI: 10.1021/acs.inorgchem.0c01707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Titanium is one of the most abundant elements on Earth but is commonly thought to have no role in biology because of its propensity to hydrolyze. Nature stabilizes hard Lewis acidic metals from hydrolysis using a variety of mechanisms, providing inspiration for how titanium can be stabilized using biological ligands. The well-characterized Due Ferri single-chain (DFsc) de novo designed protein was developed to bind and stabilize iron and provides a binding site with hard Lewis basic residues able to bind two metal ions. We demonstrate that the DFsc scaffold stably binds 2 equiv of titanium and protects them from unwanted hydrolysis. The Ti4+-DFsc protein complex was tested for its ability to hydrolytically cleave DNA, where it was seen to linearize plasmid DNA in an overnight reaction. Ti4+-DFsc is thus the first example of a functional, soluble titanium-protein complex.
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Affiliation(s)
- Alexander Paredes
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Brittany M Loh
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Olivia M Peduzzi
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Amanda J Reig
- Department of Chemistry, Ursinus College, Collegeville, Pennsylvania 19426, United States
| | - Katherine M Buettner
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
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Fernandez-Vega L, Ruiz Silva VA, Domínguez-González TM, Claudio-Betancourt S, Toro-Maldonado RE, Capre Maso LC, Ortiz KS, Pérez-Verdejo JA, González JR, Rosado-Fraticelli GT, Meléndez FP, Betancourt Santiago FM, Rivera-Rivera DA, Navarro CM, Bruno Chardón AC, Vera AO, Tinoco AD. Evaluating Ligand Modifications of the Titanocene and Auranofin Moieties for the Development of More Potent Anticancer Drugs. INORGANICS 2020; 8. [PMID: 34046448 PMCID: PMC8152503 DOI: 10.3390/inorganics8020010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Over time platinum-based anticancer drugs have dominated the market, but their side effects significantly impact the quality of life of patients. Alternative treatments are being developed all over the world. The titanocene and auranofin families of compounds, discovered through an empirical search for other metal-based therapeutics, hold tremendous promise to improve the outcomes of cancer treatment. Herein we present a historical perspective of these compounds and review current efforts focused on the evolution of their ligands to improve their physiological solution stability, cancer selectivity, and antiproliferative performance, guided by a clear understanding of the coordination chemistry and aqueous speciation of the metal ions, of the cytotoxic mechanism of action of the compounds, and the external factors that limit their therapeutic potential. Newer members of these families of compounds and their combination in novel bimetallic complexes are the result of years of scientific research. We believe that this review can have a positive impact in the development and understanding of the metal-based drugs of gold, titanium, and beyond.
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Development and future prospects of selective organometallic compounds as anticancer drug candidates exhibiting novel modes of action. Eur J Med Chem 2019; 175:269-286. [PMID: 31096151 DOI: 10.1016/j.ejmech.2019.04.062] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 03/30/2019] [Accepted: 04/23/2019] [Indexed: 01/01/2023]
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Zaki M, Hairat S, Aazam ES. Scope of organometallic compounds based on transition metal-arene systems as anticancer agents: starting from the classical paradigm to targeting multiple strategies. RSC Adv 2019; 9:3239-3278. [PMID: 35518979 PMCID: PMC9060267 DOI: 10.1039/c8ra07926a] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/26/2018] [Indexed: 02/02/2023] Open
Abstract
The advent of the clinically approved drug cisplatin started a new era in the design of metallodrugs for cancer chemotherapy. However, to date, there has not been much success in this field due to the persistence of some side effects and multi-drug resistance of cancer cells. In recent years, there has been increasing interest in the design of metal chemotherapeutics using organometallic complexes due to their good stability and unique properties in comparison to normal coordination complexes. Their intermediate properties between that of traditional inorganic and organic materials provide researchers with a new platform for the development of more promising cancer therapeutics. Classical metal-based drugs exert their therapeutic potential by targeting only DNA, but in the case of organometallic complexes, their molecular target is quite distinct to avoid drug resistance by cancer cells. Some organometallic drugs act by targeting a protein or inhibition of enzymes such as thioredoxin reductase (TrRx), while some target mitochondria and endoplasmic reticulum. In this review, we mainly discuss organometallic complexes of Ru, Ti, Au, Fe and Os and their mechanisms of action and how new approaches improve their therapeutic potential towards various cancer phenotypes. Herein, we discuss the role of structure-reactivity relationships in enhancing the anticancer potential of drugs for the benefit of humans both in vitro and in vivo. Besides, we also include in vivo tumor models that mimic human physiology to accelerate the development of more efficient clinical organometallic chemotherapeutics.
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Affiliation(s)
- Mehvash Zaki
- Department of Chemistry, King Abdulaziz University Jeddah Saudia Arabia +91 8979086156, +966 561835672
| | - Suboot Hairat
- Department of Biotechnology, Wachemo University Hossana Ethiopia
| | - Elham S Aazam
- Department of Chemistry, King Abdulaziz University Jeddah Saudia Arabia +91 8979086156, +966 561835672
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Radionuclides transform chemotherapeutics into phototherapeutics for precise treatment of disseminated cancer. Nat Commun 2018; 9:275. [PMID: 29348537 PMCID: PMC5773683 DOI: 10.1038/s41467-017-02758-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 12/21/2017] [Indexed: 12/27/2022] Open
Abstract
Most cancer patients succumb to disseminated disease because conventional systemic therapies lack spatiotemporal control of their toxic effects in vivo, particularly in a complicated milieu such as bone marrow where progenitor stem cells reside. Here, we demonstrate the treatment of disseminated cancer by photoactivatable drugs using radiopharmaceuticals. An orthogonal-targeting strategy and a contact-facilitated nanomicelle technology enabled highly selective delivery and co-localization of titanocene and radiolabelled fluorodeoxyglucose in disseminated multiple myeloma cells. Selective ablation of the cancer cells was achieved without significant off-target toxicity to the resident stem cells. Genomic, proteomic and multimodal imaging analyses revealed that the downregulation of CD49d, one of the dimeric protein targets of the nanomicelles, caused therapy resistance in small clusters of cancer cells. Similar treatment of a highly metastatic breast cancer model using human serum albumin-titanocene formulation significantly inhibited cancer growth. This strategy expands the use of phototherapy for treating previously inaccessible metastatic disease.
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Loza-Rosas SA, Saxena M, Delgado Y, Gaur K, Pandrala M, Tinoco AD. A ubiquitous metal, difficult to track: towards an understanding of the regulation of titanium(iv) in humans. Metallomics 2017; 9:346-356. [PMID: 28164202 PMCID: PMC5397357 DOI: 10.1039/c6mt00223d] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Despite the ubiquitous nature of titanium(iv) and several examples of its beneficial behavior in different organisms, the metal remains underappreciated in biology. There is little understanding of how the metal might play an important function in the human body. Nonetheless, a new insight is obtained regarding the molecular mechanisms that regulate the blood speciation of the metal to maintain it in a nontoxic and potentially bioavailable form for use in the body. This review surveys the literature on Ti(iv) application in prosthetics and in the development of anticancer therapeutics to gain an insight into soluble Ti(iv) influx in the body and its long-term impact. The limitation in analytical tools makes it difficult to depict the full picture of how Ti(iv) is transported and distributed throughout the body. An improved understanding of Ti function and its interaction with biomolecules will be helpful in developing future technologies for its imaging in the body.
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Affiliation(s)
- Sergio A Loza-Rosas
- Department of Chemistry, University of Puerto Rico, Rio Piedras, San Juan, PR 00969, USA.
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Agnihothram S, Mullis L, Townsend TA, Watanabe F, Mustafa T, Biris A, Manjanatha MG, Azevedo MP. Titanium Dioxide Nanoparticles Evoke Proinflammatory Response during Murine Norovirus Infection Despite Having Minimal Effects on Virus Replication. INTERNATIONAL JOURNAL OF NANOTECHNOLOGY IN MEDICINE & ENGINEERING 2016; 1:63-73. [PMID: 29930994 DOI: 10.25141/2474-8811-2016-3.0063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Noroviruses (NoV) have enhanced tropism for the gastrointestinal (GI) tract and are the major cause of nonbacterial gastroenteritis in humans. Titanium dioxide (TiO2) nanoparticles (NPs) used as food additives, dietary supplements, and cosmetics accumulate in the GI tract. We investigated the effect anatase TiO2 NPs on NoV replication and host response during virus infection, using murine norovirus (MNV-1) infection of RAW 264.7 macrophages. Pretreatment with 20 μg/ml anatase NPs significantly reduced the viability of macrophages alone or during virus infection, but did not alter virus replication. In contrast, pre-incubation with 2 μg/ml anatase NPs reduced virus replication fivefold at 48 h. The presence of anatase NPs during MNV-1 infection evoked a pro-inflammatory response, as measured by a significant increase in expression of cytokines, including IL-6, IFN-γ, TNFα and the TGFβ1. No genotoxic insults due to anatase TiO2 NPs alone or to their presence during MNV-1 infection were detected. This study highlights important safety considerations related to NP exposure of the GI tract in individuals infected with noroviruses or other foodborne viruses.
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Affiliation(s)
| | - Lisa Mullis
- Division of Microbiology, Jefferson, Arkansas, 72079, USA
| | - Todd A Townsend
- Division of Genetic and Molecular Toxicology, Jefferson, Arkansas, 72079, USA
| | - Fumiya Watanabe
- Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, Arkansas 72204
| | - Thikra Mustafa
- Department of Medical Bioscience, College of Veterinary Medicine, University of Kirkuk, Kirkuk, Iraq
| | - Alexandru Biris
- Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, Little Rock, Arkansas 72204
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Tinoco AD, Saxena M, Sharma S, Noinaj N, Delgado Y, Quiñones González EP, Conklin SE, Zambrana N, Loza-Rosas SA, Parks TB. Unusual Synergism of Transferrin and Citrate in the Regulation of Ti(IV) Speciation, Transport, and Toxicity. J Am Chem Soc 2016; 138:5659-65. [PMID: 27070073 DOI: 10.1021/jacs.6b01966] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human serum transferrin (sTf) is a protein that mediates the transport of iron from blood to cells. Assisted by the synergistic anion carbonate, sTf transports Fe(III) by binding the metal ion in a closed conformation. Previous studies suggest sTf's role as a potential transporter of other metals such as titanium. Ti is a widely used metal in colorants, foods, and implants. A substantial amount of Ti is leached into blood from these implants. However, the fate of the leached Ti and its transport into the cells is not known. Understanding Ti interaction with sTf assumes a greater significance with our ever increasing exposure to Ti in the form of implants. On the basis of in vitro studies, it was speculated that transferrin can bind Ti(IV) assisted by a synergistic anion. However, the role and identity of the synergistic anion(s) and the conformational state in which sTf binds Ti(IV) are not known. Here we have solved the first X-ray crystal structure of a Ti(IV)-bound sTf. We find that sTf binds Ti(IV) in an open conformation with both carbonate and citrate as synergistic anions at the metal binding sites, an unprecedented role for citrate. Studies with cell lines suggest that Ti(IV)-sTf is transported into cells and that sTf and citrate regulate the metal's blood speciation and attenuate its cytotoxic property. Our results provide the first glimpse into the citrate-transferrin synergism in the regulation of Ti(IV) bioactivity and offers insight into the future design of Ti(IV)-based anticancer drugs.
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Affiliation(s)
| | | | | | - Nicholas Noinaj
- Department of Biological Sciences, Purdue University , 240 S. Martin Jischke Drive, Hockmeyer Hall, West Lafayette, Indiana 47907, United States
| | | | | | | | | | | | - Timothy B Parks
- VA Caribbean Healthcare System, 10 Casia Street, San Juan, Puerto Rico 00921
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Chrissanthopoulos A, Klouras N, Ntala C, Sevastos D, Dalas E. Inhibition of hydroxyapatite formation in the presence of titanocene-amino acid complexes: an experimental and computational study. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:5341. [PMID: 25578695 DOI: 10.1007/s10856-014-5341-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 08/03/2014] [Indexed: 06/04/2023]
Abstract
Organometallic compounds have been used in various fields of chemistry, medicine and materials science. Central metal, stereochemical configuration and functional groups of the substitutes give to the organometallic compounds very special and selective properties. These properties have been used successfully in selective-antitumor-targeting, as well as anti-arthritic drugs. In the present investigation we study the influence of two organometallic compounds on the inhibition of crystallization of hydroxyapatite. These compounds are complexes of Ti(IV) with the general formula [Cp2Ti(aa)2](2+)2Cl(-), where Cp = η (5)-C5H5 cyclopentadienyl and aa the amino acid glycine or alanine. The experiments were conducted according to the constant composition technique in supersaturated solutions containing calcium and phosphate ions. The kinetic results indicate a surface diffusion controlled mechanism of the hydroxyapatite (HAP) crystals. The experiments prove that the presence of [Cp2Ti(Ala)2](2+)2Cl(-) and [Cp2Ti(Gly)2](2+)2Cl(-) complexes affects drastically the profile formation rate of the HAP crystals under biological conditions. The complex with the amino acid alanine provides a stronger inhibition of the formation rate comparing to the complex with glycine. The experimental observations are supported by computer calculations.
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Fernández-Gallardo J, Elie BT, Sulzmaier FJ, Sanaú M, Ramos JW, Contel M. Organometallic Titanocene-Gold Compounds as Potential Chemotherapeutics in Renal Cancer. Study of their Protein Kinase Inhibitory Properties. Organometallics 2014; 33:6669-6681. [PMID: 25435644 PMCID: PMC4245150 DOI: 10.1021/om500965k] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Indexed: 12/24/2022]
Abstract
Early-late transition metal TiAu2 compounds [(η-C5H5)2Ti{OC(O)CH2PPh2AuCl}2] (3) and new [(η-C5H5)2Ti{OC(O)-4-C6H4PPh2AuCl}2] (5) were evaluated as potential anticancer agents in vitro against renal and prostate cancer cell lines. The compounds were significantly more effective than monometallic titanocene dichloride and gold(I) [{HOC(O)RPPh2}AuCl] (R = -CH2- 6, -4-C6H4- 7) derivatives in renal cancer cell lines, indicating a synergistic effect of the resulting heterometallic species. The activity on renal cancer cell lines (for 5 in the nanomolar range) was considerably higher than that of cisplatin and highly active titanocene Y. Initial mechanistic studies in Caki-1 cells in vitro coupled with studies of their inhibitory properties on a panel of 35 kinases of oncological interest indicate that these compounds inhibit protein kinases of the AKT and MAPKAPK families with a higher selectivity toward MAPKAPK3 (IC503 = 91 nM, IC505 = 117 nM). The selectivity of the compounds in vitro against renal cancer cell lines when compared to a nontumorigenic human embryonic kidney cell line (HEK-293T) and the favorable preliminary toxicity profile on C57black6 mice indicate that these compounds (especially 5) are excellent candidates for further development as potential renal cancer chemotherapeutics.
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Affiliation(s)
- Jacob Fernández-Gallardo
- Department
of Chemistry, Brooklyn College and The Graduate Center, The City University of New York, Brooklyn, New York 11210, United States
| | - Benelita T. Elie
- Department
of Chemistry, Brooklyn College and The Graduate Center, The City University of New York, Brooklyn, New York 11210, United States
| | - Florian J. Sulzmaier
- Cancer
Biology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii 96813, United States
| | - Mercedes Sanaú
- Departamento
de Química Inorgánica, Universidad
de Valencia, Burjassot, Valencia, 46100, Spain
| | - Joe W. Ramos
- Cancer
Biology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii 96813, United States
| | - María Contel
- Department
of Chemistry, Brooklyn College and The Graduate Center, The City University of New York, Brooklyn, New York 11210, United States
- Cancer
Biology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii 96813, United States
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Affiliation(s)
- Katherine M. Buettner
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Ann M. Valentine
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
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