The development of photosensitizers that function effectively in hypoxic environments and enable deep-tissue treatment remains a significant challenge in photodynamic therapy (PDT). Here, we report two novel Ir(III) complexes functionalized with fluorescein designed as efficient Type I photosensitizers for both light-driven PDT and X-ray-induced PDT (X-PDT). By populating the triplet state of the fluorescein ligands, these complexes facilitate the generation of reactive oxygen species (ROS) through electron transfer, producing superoxide anion radicals (O2•-) and hydroxyl radicals (•OH) under irradiation. The complexes exhibit pronounced phototoxicity against cancer cells, particularly under hypoxic conditions, where oxygen-dependent Type II photosensitizers are less effective. Remarkably, these complexes also demonstrate direct X-ray activation, offering a solution for deep-tissue cancer treatment. The lead complex, PS1, outperforms existing systems by efficiently generating both singlet oxygen O2(1Δg) and free radicals, enabling synergistic Type I and II PDT effects. This work represents a major advancement in the design of oxygen-independent PDT agents by using fluorescein's triplet state, with potential applications in deep-tissue and hypoxic tumor environments.
- MeSH
- fluorescein * chemie farmakologie MeSH
- fotochemoterapie * MeSH
- fotosenzibilizující látky * farmakologie chemie chemická syntéza MeSH
- iridium * chemie farmakologie MeSH
- komplexní sloučeniny * farmakologie chemie chemická syntéza MeSH
- lidé MeSH
- molekulární struktura MeSH
- nádorové buněčné linie MeSH
- protinádorové látky * farmakologie chemie chemická syntéza MeSH
- reaktivní formy kyslíku metabolismus MeSH
- rentgenové záření MeSH
- screeningové testy protinádorových léčiv MeSH
- viabilita buněk účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fluorescein * MeSH
- fotosenzibilizující látky * MeSH
- iridium * MeSH
- komplexní sloučeniny * MeSH
- protinádorové látky * MeSH
- reaktivní formy kyslíku MeSH
Dinuclear complex [Ir2(μ-L1)(η5-Cp*)2Cl2](PF6)2 (1) exhibits low micromolar cytotoxic activity in vitro in various human cancer cells (GI50 = 1.7-3.0 μM) and outperformed its mononuclear analogue [Ir(η5-Cp*)Cl(L2)]PF6 (2; GI50 > 40.0 μM); Cp* = pentamethylcyclopentadienyl, L1 = 4-chloro-2,6-bis[5-(pyridin-2-yl)-1,3,4-thiadiazol-2-yl]pyridine, L2 = 5-(pyridin-2-yl)-1,3,4-thiadiazol-2-amine. Compound 1 upregulated the Keap1/Nrf2 oxidative stress-protective pathway in the treated MV4-11 acute myeloid leukemia cells. In connection with the redox-mediated mode of action of 1, its NADH-oxidizing activity was detected in solution (1H NMR), while NAD+ remained intact (with formate as a hydride source). Surprisingly, only negligible NADH oxidation was detected in the presence of the reduced glutathione and ascorbate. Following the results of in-solution experiments, NAD(H) concentration was assessed in 1-treated MV4-11 cancer cells. Besides the intracellular NADH oxidation in the presence of 1, the induced oxidative stress also led to a decrease of NAD+, resulting in depletion of both NAD+/NADH coenzymes. The discussed findings provide new insight into the biochemical effects of catalytic anticancer compounds that induce cell death via a redox-mediated mode of action.
- Klíčová slova
- Antiproliferative activity, Complex, Dinuclear, Iridium, NADH, Reactive oxygen species,
- MeSH
- faktor 2 související s NF-E2 * metabolismus MeSH
- iridium * chemie farmakologie MeSH
- komplexní sloučeniny farmakologie chemie chemická syntéza MeSH
- lidé MeSH
- NAD * metabolismus MeSH
- nádorové buněčné linie MeSH
- oxidace-redukce MeSH
- oxidační stres účinky léků MeSH
- protinádorové látky * farmakologie chemie chemická syntéza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- faktor 2 související s NF-E2 * MeSH
- iridium * MeSH
- komplexní sloučeniny MeSH
- NAD * MeSH
- NFE2L2 protein, human MeSH Prohlížeč
- protinádorové látky * MeSH
In this paper, we present the synthesis of four new complexes: the dimeric precursor [Ir(dmppz)2(μ-Cl)]2 (1) (Hdmppz - 3,5-dimethyl-1-phenyl-1H-pyrazole) and heteroleptic bis-cyclometalated complexes: [Ir(dmppz)2(Py2CO)]PF6·½CH2Cl2 (2), [Ir(dmppz)2(H2biim)]PF6·H2O (3), and [Ir(dmppz)2(PyBIm)]PF6 (4), with auxiliary N,N-donor ligands: 2-di(pyridyl)ketone (Py2CO), 2,2'-biimidazole (H2biim) and 2-(2'-pyridyl)benzimidazole (PyBIm). In the obtained complexes, SC-X-ray analysis revealed that Ir(III) has an octahedral coordination sphere with chromophores of the type {IrN2C2Cl2} (1) or {IrN4C2} (2-4). The complexes obtained, which have been fully characterised by physicochemical methods (CHN, TG, FTIR, UV-Vis, PL and 1H, 13C, 15N NMR), were used to continue our studies on the factors influencing the cytotoxic properties of potential chemotherapeutic agents (in vitro). To this end, the following studies are presented: (i) comparative analysis of the effects on the biological properties of N,N-donor ligands and C,N-donor ligands in the studied complexes, (ii) studies of the interactions of the compounds with the selected molecular target: DNA and BSA (UV-Vis, CD and PL methods), (iii) and the reactivity towards redox molecules: GSH, NADH (UV-Vis and/or ESI-MS methods), (iv) cytotoxic activity (IC50) of potential chemotherapeutics against MCF-7, K-562 and CCRF-CEM cell lines.
- MeSH
- DNA chemie metabolismus MeSH
- fotochemické procesy MeSH
- iridium * chemie farmakologie MeSH
- komplexní sloučeniny * farmakologie chemie chemická syntéza MeSH
- kvantová teorie MeSH
- lidé MeSH
- ligandy MeSH
- molekulární modely MeSH
- molekulární struktura MeSH
- nádorové buněčné linie MeSH
- proliferace buněk * účinky léků MeSH
- protinádorové látky * farmakologie chemie chemická syntéza MeSH
- pyrazoly * chemie farmakologie chemická syntéza MeSH
- screeningové testy protinádorových léčiv MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- DNA MeSH
- iridium * MeSH
- komplexní sloučeniny * MeSH
- ligandy MeSH
- protinádorové látky * MeSH
- pyrazole MeSH Prohlížeč
- pyrazoly * MeSH
Herein, we report the development of a macromolecular multifunctional imaging tool for biological investigations, which is comprised of an N-(2-hydroxypropyl)methacrylamide backbone, iridium-based luminescent probe, glutamate carboxypeptidase II (GCPII) targeting ligand, and biotin affinity tag. The iridium luminophore is a tris-cyclometalated complex based on [Ir(ppy)3] with one of its 2-phenylpyridine ligands functionalized to allow conjugation. Synthesized macromolecular probes differed in the structure of the polymer and content of the iridium complex. The applicability of the developed imaging tools has been tested in flow cytometry (FACS) based assay, laser confocal microscopy, and fluorescence lifetime imaging microscopy (FLIM). The FACS analysis has shown that the targeted iBodies containing the iridium luminophore exhibit selective labelling of GCPII expressing cells. This observation was also confirmed in the imaging experiments with laser confocal microscopy. The FLIM experiment has shown that the iBodies with the iridium label exhibit a lifetime greater than 100 ns, which distinguishes them from typically used systems labelled with organic fluorophores exhibiting short fluorescence lifetimes. The results of this investigation indicate that the system exhibits interesting properties, which supports the development of additional biological tools utilizing the key components (iridium complexes, iBody concept), primarily focusing on the longer lifetime of the iridium emitter.
- Klíčová slova
- HPMA, iBody, imaging, iridium complex,
- MeSH
- fluorescenční barviva chemie MeSH
- fluorescenční mikroskopie metody MeSH
- iridium * chemie MeSH
- konfokální mikroskopie * MeSH
- lidé MeSH
- optické zobrazování metody MeSH
- polymery * chemie MeSH
- průtoková cytometrie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Cyclometalated Ir(III) complex [Ir(L)2(dppz)]PF6 (where L = 1-methyl-2-(thiophen-2-yl)-1H-benzo[d]imidazole and dppz = dipyrido [3,2-a:2',3'-c]phenazine) (Ir1) is potent anticancer agent whose potency can be significantly increased by irradiation with blue light. Structural features of the cyclometalated Ir(III) complex Ir1 investigated in this work, particularly the presence of dppz ligand possessing an extended planar area, suggest that this complex could interact with DNA. Here, we have shown that Ir1 accumulates predominantly in mitochondria of cancer cells where effectively and selectively binds mitochondrial (mt)DNA. Additionally, the results demonstrated that Ir1 effectively suppresses transcription of mitochondria-encoded genes, especially after irradiation, which may further affect mitochondrial (and thus also cellular) functions. The observation that Ir1 binds selectively to mtDNA implies that the mechanism of its biological activity in cancer cells may also be connected with its interaction and damage to mtDNA. Further investigations revealed that Ir1 tightly binds DNA in a cell-free environment, with sequence preference for GC over AT base pairs. Although the dppz ligand itself or as a ligand in structurally similar DNA-intercalating Ru polypyridine complexes based on dppz ligand intercalates into DNA, the DNA binding mode of Ir1 comprises surprisingly a groove binding rather than an intercalation. Also interestingly, after irradiation with visible (blue) light, Ir1 was capable of cleaving DNA, likely due to the production of superoxide anion radical. The results of this study show that mtDNA damage by Ir1 plays a significant role in its mechanism of antitumor efficacy. In addition, the results of this work are consistent with the hypothesis and support the view that targeting the mitochondrial genome is an effective strategy for anticancer (photo)therapy and that the class of photoactivatable dipyridophenazine Ir(III) compounds may represent prospective substances suitable for further testing.
- Klíčová slova
- Antitumor activity, DNA cleavage, Mitochondrial DNA, Phototoxic iridium complex, Superoxide anion radicals, Transcription of mitochondria-encoded genes,
- MeSH
- iridium farmakologie chemie MeSH
- komplexní sloučeniny * farmakologie chemie MeSH
- ligandy MeSH
- mitochondriální DNA MeSH
- mitochondrie MeSH
- nádory * MeSH
- prospektivní studie MeSH
- protinádorové látky * farmakologie chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- iridium MeSH
- komplexní sloučeniny * MeSH
- ligandy MeSH
- mitochondriální DNA MeSH
- protinádorové látky * MeSH
A second-generation series of biscyclometalated 2-(5-aryl-thienyl)-benzimidazole and -benzothiazole Ir(III) dppz complexes [Ir(C^N)2(dppz)]+, Ir1-Ir4, were rationally designed and synthesized, where the aryl group attached to the thienyl ring was p-CF3C6H4 or p-Me2NC6H4. These new Ir(III) complexes were assessed as photosensitizers to explore the structure-activity correlations for their potential use in biocompatible anticancer photodynamic therapy. When irradiated with blue light, the complexes exhibited high selective potency across several cancer cell lines predisposed to photodynamic therapy; the benzothiazole derivatives (Ir1 and Ir2) were the best performers, Ir2 being also activatable with green or red light. Notably, when irradiated, the complexes induced leakage of lysosomal content into the cytoplasm of HeLa cancer cells and induced oncosis-like cell death. The capability of the new Ir complexes to photoinduce cell death in 3D HeLa spheroids has also been demonstrated. The investigated Ir complexes can also catalytically photo-oxidate NADH and photogenerate 1O2 and/or •OH in cell-free media.
- MeSH
- benzothiazoly MeSH
- fotosenzibilizující látky farmakologie terapeutické užití MeSH
- fototoxická dermatitida * farmakoterapie MeSH
- iridium farmakologie MeSH
- komplexní sloučeniny * farmakologie MeSH
- lidé MeSH
- lyzozomy MeSH
- nádorové buněčné linie MeSH
- nádory * farmakoterapie MeSH
- protinádorové látky * farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- benzothiazoly MeSH
- fotosenzibilizující látky MeSH
- iridium MeSH
- komplexní sloučeniny * MeSH
- protinádorové látky * MeSH
We report for the first time the use of two live-cell imaging agents from the group of luminescent transition metal complexes (IRAZOLVE-MITO and REZOLVE-ER) as cathodoluminescent probes. This first experimental demonstration shows the application of both probes for the identification of cellular structures at the nanoscale and near the native state directly in the cryo-scanning electron microscope. This approach can potentially be applied to correlative and multimodal approaches and used to target specific regions within vitrified samples at low electron beam energies.
- MeSH
- iridium chemie MeSH
- komplexní sloučeniny * chemie MeSH
- luminiscence MeSH
- rhenium * chemie MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- iridium MeSH
- komplexní sloučeniny * MeSH
- rhenium * MeSH
In this work, the mechanism underlying the anticancer activity of a photoactivatable Ir(III) compound of the type [Ir(C^N)2(dppz)][PF6] where C^N = 1-methyl-2-(2'-thienyl)benzimidazole (complex 1) was investigated. Complex 1 photoactivated by visible light shows potent activity against highly aggressive and poorly treatable Rhabdomyosarcoma (RD) cells, the most frequent soft tissue sarcomas of children. This remarkable activity of 1 was observed not only in RD cells cultured in 2D monolayers but, more importantly, also in 3D spheroids, which resemble in many aspects solid tumors and serve as a promising model to mimic the in vivo situation. Importantly, photoactivated 1 kills not only differentiated RD cells but also even more effectively cancer stem cells (CSCs) of RD. One of the factors responsible for the activity of irradiated 1 in RD CSCs is its ability to produce ROS in these cells more effectively than in differentiated RD cells. Moreover, photoactivated 1 caused in RD differentiated cells and CSCs a significant decrease of mitochondrial membrane potential and promotes opening mitochondrial permeability transition pores in these cells, a mechanism that has never been demonstrated for any other metal-based anticancer complex. The results of this work give evidence that 1 has a potential for further evaluation using in vivo models as a promising chemotherapeutic agent for photodynamic therapy of hardly treatable human Rhabdomyosarcoma, particularly for its activity in both stem and differentiated cancer cells.
- Klíčová slova
- Antitumor activity, Cancer stem cells, Mitochondria, Phototoxic iridium complex, Rhabdomyosarcoma cells,
- MeSH
- dítě MeSH
- iridium farmakologie MeSH
- komplexní sloučeniny * farmakologie MeSH
- lidé MeSH
- mitochondrie MeSH
- nádorové buněčné linie MeSH
- nádorové kmenové buňky MeSH
- protinádorové látky * farmakologie MeSH
- rhabdomyosarkom * farmakoterapie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- iridium MeSH
- komplexní sloučeniny * MeSH
- protinádorové látky * MeSH
Four bipyridine-type ligands variably derivatized with two bioactive groups (taken from ethacrynic acid, flurbiprofen, biotin, and benzylpenicillin) were prepared via sequential esterification steps from commercial 2,2'-bipyridine-4,4'-dicarboxylic acid and subsequently coordinated to ruthenium(II) p-cymene and iridium(III) pentamethylcyclopentadienyl scaffolds. The resulting complexes were isolated as nitrate salts in high yields and fully characterized by analytical and spectroscopic methods. NMR and MS studies in aqueous solution and in cell culture medium highlighted a substantial stability of ligand coordination and a slow release of the bioactive fragments in the latter case. The complexes were assessed for their antiproliferative activity on four cancer cell lines, showing cytotoxicity to the low micromolar level (equipotent with cisplatin). Additional biological experiments revealed a multimodal mechanism of action of the investigated compounds, involving DNA metalation and enzyme inhibition. Synergic effects provided by specific combinations of metal and bioactive fragments were identified, pointing toward an optimal ethacrynic acid/flurbiprofen combination for both Ru(II) and Ir(III) complexes.
- MeSH
- iridium chemie farmakologie MeSH
- komplexní sloučeniny chemická syntéza chemie farmakologie MeSH
- lidé MeSH
- ligandy MeSH
- molekulární struktura MeSH
- nádorové buňky kultivované MeSH
- poškození DNA MeSH
- proliferace buněk účinky léků MeSH
- protinádorové látky chemická syntéza chemie farmakologie MeSH
- pyridiny chemie farmakologie MeSH
- ruthenium chemie farmakologie MeSH
- screeningové testy protinádorových léčiv MeSH
- viabilita buněk účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- iridium MeSH
- komplexní sloučeniny MeSH
- ligandy MeSH
- protinádorové látky MeSH
- pyridiny MeSH
- ruthenium MeSH
Although cyclometalated IrIII complexes have emerged as promising photosensitizers for photodynamic therapy, some key drawbacks still hamper clinical translation, such as operability in the phototherapeutic window and reactive oxygen species (ROS) production efficiency and selectivity. In this work, a cyclometalated IrIII complex conjugated to a far-red-emitting coumarin, IrIII -COUPY, is reported with highly favourable properties for cancer phototherapy. IrIII -COUPY was efficiently taken up by HeLa cells and showed no dark cytotoxicity and impressive photocytotoxicity indexes after irradiation with green and blue light, even under hypoxia. Importantly, a clear correlation between cell death and intracellular generation of superoxide anion radicals after visible light irradiation was demonstrated. This strategy opens the door to novel fluorescent photodynamic therapy agents with promising applications in theragnosis.
- Klíčová slova
- conjugation, coumarin, cyclometalated iridium(III) complexes, photodynamic therapy, photosensitizer,
- MeSH
- fotochemoterapie MeSH
- HeLa buňky MeSH
- hypoxie buňky MeSH
- iridium chemie MeSH
- komplexní sloučeniny chemie farmakologie terapeutické užití MeSH
- kumariny chemie MeSH
- lidé MeSH
- nádory farmakoterapie patologie MeSH
- protinádorové látky chemie farmakologie terapeutické užití MeSH
- superoxidy metabolismus MeSH
- světlo MeSH
- viabilita buněk účinky léků účinky záření MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- coumarin MeSH Prohlížeč
- iridium MeSH
- komplexní sloučeniny MeSH
- kumariny MeSH
- protinádorové látky MeSH
- superoxidy MeSH
