8. COORDINATION COMPLEXES OF TITANIUM(IV) FOR ANTICANCER THERAPY
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Edit Y. Tshuva
Abstract
Titanium(IV) coordination complexes represent attractive alternatives to platinumbased anticancer drugs. The advantage of the titanium metal lies in its low toxicity, and the hydrolysis of titanium(IV) coordination complexes in biological water-based environment to the safe and inert titanium dioxide is an enormous benefit. On the other hand, the rapid hydrolysis of titanium(IV) complexes in biological environment and their rich aquatic chemistry hampered the exploration and the development of effective compounds. Titanium(IV) complexes were the first to enter clinical trials for cancer treatment following the success of platinum-based chemotherapy, with the pioneering compounds titanocene dichloride and budotitane. Despite the high efficacy and low toxicity observed in vivo, the compounds failed the trials due to insufficient efficacy to toxicity ratio and formulation complications. The rapid hydrolysis of the complexes led to formation of multiple undefined aggregates and difficulties in isolating and identifying the particular active species and its precise cellular target. Numerous derivatives with different labile ligands or substitutions on the inert ones contributed to improve the complex anticancer features, and the best ones were comparable with, and occasionally better than cisplatin. Hydrolytic stability was improved in some cases but remained challenging. The following generation of phenolato-based complexes that came three decades later exhibited high activity and markedly improved stability, where no dissociation was observed for weeks in biological solutions. Complexes of no labile ligands whatsoever that remain intact in solution demonstrated in vitro and in vivo efficacy, with no signs of toxicity to the treated animals. Mechanistic insights gained for the different complexes analyzed include, among others, possible interaction with DNA and induction of apoptosis. Such complexes are highly promising for future exploration and clinical development.
Abstract
Titanium(IV) coordination complexes represent attractive alternatives to platinumbased anticancer drugs. The advantage of the titanium metal lies in its low toxicity, and the hydrolysis of titanium(IV) coordination complexes in biological water-based environment to the safe and inert titanium dioxide is an enormous benefit. On the other hand, the rapid hydrolysis of titanium(IV) complexes in biological environment and their rich aquatic chemistry hampered the exploration and the development of effective compounds. Titanium(IV) complexes were the first to enter clinical trials for cancer treatment following the success of platinum-based chemotherapy, with the pioneering compounds titanocene dichloride and budotitane. Despite the high efficacy and low toxicity observed in vivo, the compounds failed the trials due to insufficient efficacy to toxicity ratio and formulation complications. The rapid hydrolysis of the complexes led to formation of multiple undefined aggregates and difficulties in isolating and identifying the particular active species and its precise cellular target. Numerous derivatives with different labile ligands or substitutions on the inert ones contributed to improve the complex anticancer features, and the best ones were comparable with, and occasionally better than cisplatin. Hydrolytic stability was improved in some cases but remained challenging. The following generation of phenolato-based complexes that came three decades later exhibited high activity and markedly improved stability, where no dissociation was observed for weeks in biological solutions. Complexes of no labile ligands whatsoever that remain intact in solution demonstrated in vitro and in vivo efficacy, with no signs of toxicity to the treated animals. Mechanistic insights gained for the different complexes analyzed include, among others, possible interaction with DNA and induction of apoptosis. Such complexes are highly promising for future exploration and clinical development.
Kapitel in diesem Buch
- Frontmatter i
- About the Editors v
- Historical Development and Perspectives of the Series vii
- Preface to Volume 18 ix
- Contents xiii
- Contributors to Volume 18 xix
- Titles of Volumes 1–44 in the Metal Ions in Biological Systems Series xxiii
- Contents of Volumes in the Metal Ions in Life Sciences Series xxv
- 1. CISPLATIN AND OXALIPLATIN: OUR CURRENT UNDERSTANDING OF THEIR ACTIONS 1
- 2. POLYNUCLEAR PLATINUM COMPLEXES. STRUCTURAL DIVERSITY AND DNA BINDING 43
- 3. PLATINUM(IV) PRODRUGS 69
- 4. METALLOGLYCOMICS 109
- 5. THE DECEPTIVELY SIMILAR RUTHENIUM(III) DRUG CANDIDATES KP1019 AND NAMI-A HAVE DIFFERENT ACTIONS. WHAT DID WE LEARN IN THE PAST 30 YEARS? 141
- 6. MULTINUCLEAR ORGANOMETALLIC RUTHENIUM-ARENE COMPLEXES FOR CANCER THERAPY 171
- 7. MEDICINAL CHEMISTRY OF GOLD ANTICANCER METALLODRUGS 199
- 8. COORDINATION COMPLEXES OF TITANIUM(IV) FOR ANTICANCER THERAPY 219
- 9. HEALTH BENEFITS OF VANADIUM AND ITS POTENTIAL AS AN ANTICANCER AGENT 251
- 10. GALLIUM COMPLEXES AS ANTICANCER DRUGS 281
- 11. NON-COVALENT METALLO-DRUGS: USING SHAPE TO TARGET DNA AND RNA JUNCTIONS AND OTHER NUCLEIC ACID STRUCTURES 303
- 12. NUCLEIC ACID QUADRUPLEXES AND METALLO-DRUGS 325
- 13. ANTITUMOR METALLODRUGS THAT TARGET PROTEINS 351
- 14. METALLOINTERCALATORS AND METALLOINSERTORS: STRUCTURAL REQUIREMENTS FOR DNA RECOGNITION AND ANTICANCER ACTIVITY 387
- 15. IRON AND ITS ROLE IN CANCER DEFENSE: A DOUBLE-EDGED SWORD 437
- 16. COPPER COMPLEXES IN CANCER THERAPY 469
- 17. TARGETING ZINC(II) SIGNALLING TO PREVENT CANCER 507
- SUBJECT INDEX 531
Kapitel in diesem Buch
- Frontmatter i
- About the Editors v
- Historical Development and Perspectives of the Series vii
- Preface to Volume 18 ix
- Contents xiii
- Contributors to Volume 18 xix
- Titles of Volumes 1–44 in the Metal Ions in Biological Systems Series xxiii
- Contents of Volumes in the Metal Ions in Life Sciences Series xxv
- 1. CISPLATIN AND OXALIPLATIN: OUR CURRENT UNDERSTANDING OF THEIR ACTIONS 1
- 2. POLYNUCLEAR PLATINUM COMPLEXES. STRUCTURAL DIVERSITY AND DNA BINDING 43
- 3. PLATINUM(IV) PRODRUGS 69
- 4. METALLOGLYCOMICS 109
- 5. THE DECEPTIVELY SIMILAR RUTHENIUM(III) DRUG CANDIDATES KP1019 AND NAMI-A HAVE DIFFERENT ACTIONS. WHAT DID WE LEARN IN THE PAST 30 YEARS? 141
- 6. MULTINUCLEAR ORGANOMETALLIC RUTHENIUM-ARENE COMPLEXES FOR CANCER THERAPY 171
- 7. MEDICINAL CHEMISTRY OF GOLD ANTICANCER METALLODRUGS 199
- 8. COORDINATION COMPLEXES OF TITANIUM(IV) FOR ANTICANCER THERAPY 219
- 9. HEALTH BENEFITS OF VANADIUM AND ITS POTENTIAL AS AN ANTICANCER AGENT 251
- 10. GALLIUM COMPLEXES AS ANTICANCER DRUGS 281
- 11. NON-COVALENT METALLO-DRUGS: USING SHAPE TO TARGET DNA AND RNA JUNCTIONS AND OTHER NUCLEIC ACID STRUCTURES 303
- 12. NUCLEIC ACID QUADRUPLEXES AND METALLO-DRUGS 325
- 13. ANTITUMOR METALLODRUGS THAT TARGET PROTEINS 351
- 14. METALLOINTERCALATORS AND METALLOINSERTORS: STRUCTURAL REQUIREMENTS FOR DNA RECOGNITION AND ANTICANCER ACTIVITY 387
- 15. IRON AND ITS ROLE IN CANCER DEFENSE: A DOUBLE-EDGED SWORD 437
- 16. COPPER COMPLEXES IN CANCER THERAPY 469
- 17. TARGETING ZINC(II) SIGNALLING TO PREVENT CANCER 507
- SUBJECT INDEX 531
