DNA interaction and photodynamic antitumor activity of transition metal mono-hydroxyl corrole

Direct Conjugation of Gallium-(III)-Corroles to Short Interfering RNA(siRNA) Providing Real-Time siRNA Imaging and Gene Silencing

Discovering new modifications for oligonucleotide therapeutics is essential for expanding its application to new targets and diseases. In this project, we focus on conjugating metaled ligands to short interfering RNAs (siRNAs) to investigate robust and simple conjugation methods for adding new properties such as real-time imaging to the siRNA. Here we report the chemical synthesis of novel Ga-(III)-corroles for their direct conjugation to siRNAs. Ga-(III)-corrole-siRNAs showed promising results when evaluated for gene silencing and live cell imaging. The knockdown activity of the firefly luciferase reporter gene was measured to evaluate gene silencing activity. Gene silencing studies from two 5'-Ga-(III)-labeled-siRNAs exhibited dose-dependent knockdown with IC50s of 812.7 and 451.4 pM, which is comparable to wild-type (IC50=439.7 pM) in the absence of red light, and IC50s of 562.9 and 354.5 pM, which is also comparable to wild-type (IC50=337.4 pM), in the presence of red light. In addition, imaging studies with Ga-(III)-corrole-modified siRNAs showed intense fluorescence in HeLa cells, highlighting that the Ga-(III)-corrole modification is an effective fluorophore for siRNA tracing and imaging. Moreover, the photodynamic activity of free base corrole vs the Ga-(III)-corrole was evaluated. Results show an increase of light cytotoxicity of the corrole ligand upon the addition of Ga-(III); however, no phototoxicity was observed when Ga-(III) ligands were linked to siRNA. In conclusion, Ga-(III)-corrole-siRNAs show promising results for applications in simultaneous real-time imaging and gene silencing.

Azide-modified corrole phosphorus complexes for endoplasmic reticulum-targeted fluorescence bioimaging and effective cancer photodynamic therapy

Study on corrole photosensitizers (PSs) for photodynamic therapy (PDT) has made remarkable progress. Targeted delivery of PSs is of great significance for enhancing therapeutic efficiency, decreasing the dosage, and reducing systemic toxicity during PDT. The development of PSs that can be specifically delivered to the subcellular organelle is still an attractive and challenging work. Herein, we synthesize a series of azide-modified corrole phosphorus and gallium complex PSs, in which phosphorus corrole 2-P could not only precisely target the endoplasmic reticulum (ER) with a Pearson correlation coefficient (PCC) up to 0.92 but also possesses the highest singlet oxygen quantum yields (ΦΔ = 0.75). This renders it remarkable PDT activity at a very low dosage (IC50 = 23 nM) towards HepG2 tumor cell line while ablating solid tumors in vivo with excellent biosecurity. Furthermore, 2-P exhibits intense red fluorescence (ΦF = 0.25), outstanding photostability, and a large Stokes shift (190 nm), making it a promising fluorescent probe for ER. This study provides a clinically potential photosensitizer for cancer photodynamic therapy and a promising ER fluorescent probe for bioimaging.

Photophysical, photobiological, and biomolecule-binding properties of new tri-cationic meso-tri(2-thienyl)corroles with Pt(II) and Pd(II) polypyridyl derivatives

We report the synthesis and characterization of new tri-cationic corrole derivatives, containing Pt(II) or Pd(II) complexes attached at the peripheral position of thienyl moieties. Corrole derivatives were characterized through microanalysis, electrochemical, spectrometry and spectroscopy analysis. Singlet and triplet excited-states are investigated by photophysical/theoretical calculation methods and photobiological parameters were also evaluated spectroscopic techniques (UV-Vis and EPR). Also, the binding capacity of each corrole derivative with nucleic acids (DNA) and human serum albumin (HSA) was determined by UV-Vis, steady-state, and time-resolved fluorescence spectroscopy, combined with molecular docking analysis. Moreover, the new corroles containing peripheral complexes improve their interactions with biomacromolecules, generate reactive oxygen species under light source irradiation studied and has potential for application in photodynamic therapeutic processes.

Recent Advances in Cancer Therapeutic Copper-Based Nanomaterials for Antitumor Therapy

Copper serves as a vital microelement which is widely present in the biosystem, functioning as multi-enzyme active site, including oxidative stress, lipid oxidation and energy metabolism, where oxidation and reduction characteristics are both beneficial and lethal to cells. Since tumor tissue has a higher demand for copper and is more susceptible to copper homeostasis, copper may modulate cancer cell survival through reactive oxygen species (ROS) excessive accumulation, proteasome inhibition and anti-angiogenesis. Therefore, intracellular copper has attracted great interest that multifunctional copper-based nanomaterials can be exploited in cancer diagnostics and antitumor therapy. Therefore, this review explains the potential mechanisms of copper-associated cell death and investigates the effectiveness of multifunctional copper-based biomaterials in the field of antitumor therapy.

Gallium(III) Amide Corroles: DNA Interaction and Photodynamic Activity in Cancer Cells

A series of gallium(III) amide corroles including meso-5,15-bis(pentafluorophenyl)-10-(4-Pyridinamide-phenyl)corrole gallium (III) (1-Ga), meso-5,15-bis(pentafluorophenyl)-10-(4-Furamide-phenyl)corrole gallium(III) (2-Ga) and meso-5,15-bis(pentafluorophenyl)-10-(4-Thiophenamide-phenyl)corrole gallium(III) (3-Ga) were synthesized. The interaction of these complexes with DNA and their photodynamic antitumor activities have been studied. UV spectra titration showed that these gallium(III) corroles interact with calf thymus DNA (CT-DNA) through an external binding mode. All three gallium(III) corroles can effectively generate singlet oxygen under illumination and have good photostability. Among the three gallium(III) corroles, 2-Ga exhibited excellent photodynamic antitumor activity against the tested tumor cell lines under light irradiation (625±2 nm, 0.3 mW/cm2 , 1.08 J/cm2 ). The best phototoxicity was observed by 2-Ga against HepG2 cells (IC50 =6.3±0.9), which is even better than temoporfin (IC50 =8.4±1.8). It could block HepG2 cells in the sub-G0 phase and effectively induce apoptosis of HepG2 cells under 625 nm light irradiation.

Photodynamic antitumor activity of Gallium(III) and Phosphorus(V) complexes of trimethoxyl A2B triaryl corrole

Two new trimethoxyl A₂B triaryl corroles 10-(2,4,6-trimethoxyphenyl)-5,15-bis(pentafluorophenyl)- corrole (1) and 10-(3,4,5-trimethoxyphenyl)-5,15-bis(pentafluorophenyl)-corrole (2) and their gallium(III) and phosphorus(V) (1-Ga, 1-P, 2-Ga and 2-P) complexes had been prepared and well characterized by UV-vis, NMR and HR-MS. Among all compounds, 2-Ga, 1-P and 2-P showed excellent in vivo photodynamic activity against the MDA-MB-231, A549, Hela and HepG2 cell lines upon light irradiation at 625 nm. And 2-P even exhibited higher phototoxicity than the clinical photosensitizer temoporfin. Also, 2-P exhibited the highest singlet oxygen quantum yield and photostability. The preliminary investigation revealed that 2-P could be rapidly absorbed by tumor cells and mainly located in the cytoplasm. After photodynamic therapy (PDT) treatment with 2-P, mitochondrial membrane potential destruction, intracellular ROS level increasing and nuclear fragmentation of cancer cells could be observed. Cell cycle analysis demonstrated that the 2-P PDT may cause tumor cell arrest at sub-G1 stage and induce early and late apoptosis of cells. These results suggest that 2-P is a promising candidate as a photosensitizer for photodynamic therapy.

Reaction of Corroles with Sarcosine and Paraformaldehyde: A New Facet of Corrole Chemistry

Details on the unexpected formation of two new (dimethylamino)methyl corrole isomers from the reaction of 5,10,15-tris(pentafluorophenyl)corrolatogallium(III) with sarcosine and paraformaldehyde are presented. Semi-empirical calculations on possible mechanism pathways seem to indicate that the new compounds are probably formed through a Mannich-type reaction. The extension of the protocol to the free-base 5,10,15-tris(pentafluorophenyl)corrole afforded an unexpected new seven-membered ring corrole derivative, confirming the peculiar behavior of corroles towards known reactions when compared to the well-behaved porphyrin counterparts.

A Dual Therapeutic System Based on Corrole-siRNA Conjugates

Corrole molecules are a new generation of photosensitizers (PS) due to their ease of tunability for different medical applications. Their ability to initiate cellular death using a wide range of...

Photodynamic Therapy of Inorganic Complexes for the Treatment of Cancer†

Photodynamic therapy (PDT) is a medicinal tool that uses a photosensitizer and a light source to treat several conditions, including cancer. PDT uses reactive oxygen species such as cytotoxic singlet oxygen (¹ O₂ ) to induce cell death in cancer cells. Chemotherapy has historically utilized the cytotoxic effects of many metals, especially transition metal complexes. However, chemotherapy is a systemic treatment so all cells in a patient's body are exposed to the same cytotoxic effects. Transition metal complexes have also shown high cytotoxicity as PDT agents. PDT is a potential localized method for treating several cancer types by using inorganic complexes as photosensitizing agents. This review covers several in vitro and in vivo studies, as well as clinical trials that reported on the anticancer properties of inorganic pharmaceuticals used in PDT against different types of cancer.

Iron(III) Complex-Functionalized Gold Nanocomposite as a Strategic Tool for Targeted Photochemotherapy in Red Light

Iron(III)-phenolate/carboxylate complexes exhibiting photoredox chemistry and photoactivated reactive oxygen species (ROS) generation at their ligand-to-metal charge-transfer (LMCT) bands have emerged as potential strategic tools for photoactivated chemotherapy. Herein, the synthesis, in-depth characterization, photochemical assays, and remarkable red light-induced photocytotoxicities in adenocarcinomic human immortalized human keratinocytes (HaCaT) and alveolar basal epithelial (A549) cells of iron(III)-phenolate/carboxylate complex of molecular formula, [Fe(L¹)(L²)] (1), where L¹ is bis(3,5 di-tert-butyl-2-hydroxybenzyl)glycine and L² is 5-(1,2-dithiolan-3-yl)-N-(1,10-phenanthroline-5-yl)pentanamide, and the gold nanocomposite functionalized with complex 1 (1-AuNPs) are reported. There was a significant red shift in the UV-visible absorption band on functionalization of complex 1 to the gold nanoparticles (λ_max: 573 nm, 1; λ_max: 660 nm, 1-AuNPs), rendering the nanocomposite an ideal candidate for photochemotherapeutic applications. The notable findings in our present studies are (i) the remarkable cytotoxicity of the nanocomposite (1-AuNPs) to A549 (IC₅₀: 0.006 μM) and HaCaT (IC₅₀: 0.0075 μM) cells in red light (600-720 nm, 30 J/cm²) while almost nontoxic (IC₅₀ > 500 μg/mL, 0.053 μM) in the dark, (ii) the nontoxicity of 1-AuNPs to normal human diploid fibroblasts (WI-38) or human peripheral lung epithelial (HPL1D) cells (IC₅₀ > 500 μg/mL, 0.053 μM) both in the dark and red light signifying the target-specific anticancer activity of the nanocomposite, (iii) localization of 1-AuNPs in mitochondria and partly nucleus, (iv) remarkable red light-induced generation of reactive oxygen species (ROS: ¹O₂, ^•OH) in vitro, (v) disruption of the mitochondrial membrane due to enhanced oxidative stress, and (vi) caspase 3/7-dependent apoptosis. A similar cytotoxic profile of complex 1 was another key finding of our studies. Overall, our current investigations show a new red light-absorbing iron(III)-phenolate/carboxylate complex-functionalized gold nanocomposite (1-AuNPs) as the emerging next-generation iron-based photochemotherapeutic agent for targeted cancer treatment modality.

Photodynamic antitumor activity of Ru(ii) complexes of imidazo-phenanthroline conjugated hydroxybenzoic acid as tumor targeting photosensitizers

Two novel Ru(ii) polypyridyl complexes bearing imidazo-phenanthroline conjugated hydroxybenzoic acid groups were designed to enhance the tumor targeting ability as photosensitizers for photodynamic therapy. [Ru(bpy)2(phcpip)] (ClO4)2 (Ru-1) and [Ru(bpy)2(ohcpip)] (ClO4)2 (Ru-2) (bpy = 2,2'-bipyridine; phcpip = 2-(3-carboxyl-4-hydroxyphenyl) imidazo [4,5-f]phenanthroline; ohcpip = 2-(2-hydroxyl-3-carboxyphenyl) imidazo [4,5-f] [1,10] phenanthroline) were synthesized and their photodynamic antitumor activities were investigated. Both complexes displayed high photocytotoxicity toward cancerous cell lines HepG2, A549, MCF-7, and MDA-MB-231, but low photocytotoxicity toward normal cell lines GES-1 and Huvec. They were mainly localized at the nucleus of HepG2 cells after 24 h incubation, arrested the cell cycle at the G2/M phase and induced cancer cell apoptosis through reactive oxygen species (ROS) mediated pathways. Tumor targeting of the complexes is attributed to stronger molecular binding to DNA.

Halogenated Gallium Corroles:DNA Interaction and Photodynamic Antitumor Activity

A series of halogenated gallium corroles were synthesized and characterized by UV-vis, HRMS, NMR, and FT-IR. The interaction between these gallium corroles and calf thymus DNA had been investigated by spectroscopic methods. These gallium corroles would interact with CT-DNA via an outside binding mode. The photodynamic antitumor activity in vitro of these gallium corroles toward different cell lines had also been tested. 3-Ga displayed low cytotoxicity to normal cells under both light and dark conditions but high phototoxicity to liver cancer cells HepG2. The vitro experiment results showed that 3-Ga could be efficiently absorbed by tumor cells. After light illumination, it may induce reactive oxygen species (ROS) and cause destruction of the mitochondrial membrane potential, which may finally trigger tumor cell apoptosis. Flow cytometry results showed that HepG2 cells were mainly distributed in the sub-G0 phase, which corresponds to cells with highly fragmented DNA or dead cells generally. This suggests that 3-Ga could lead to tumor cell apoptosis after light illumination.

Fluorescent pyrene moiety in fluorinated C6F5-corroles increases the interaction with HSA and CT-DNA

Two fluorinated meso-C6F5-corroles (5,15-bis(pentafluorophenyl)-10-(phenyl)corrole and 5,15-bis(pentafluorophenyl)-10-(1-pyrenyl)corrole) were biologically evaluated in terms of binding affinity to human serum albumin (HSA) and calf-thymus DNA (CT-DNA) via multiple spectroscopic techniques under physiological conditions combined with molecular docking calculations. The HSA:corrole interaction is spontaneous and moderate via static binding, disturbing both secondary and tertiary albumin structures at high fluorinated corrole concentrations. The competitive binding studies indicated positive cooperativity or allosteric activation, while molecular docking calculations suggested that both fluorinated corroles bind preferentially inside subdomains IIA and IB (sites I and III, respectively). The experimental CT-DNA binding assays indicated that fluorinated corroles interact spontaneously by non-classical modes in the minor groove of the CT-DNA strands via static fluorescence quenching mechanism. Molecular docking results also showed the minor groove as the main binding site for CT-DNA. Overall, the pyrene moiety increased the interaction with HSA and CT-DNA, which is probably due to the planarity and volume that favors the pyrene unit to be buried inside the biomacromolecule pockets.

Hydroxy-corrole and its gallium(III) complex as new photosensitizer for photodynamic therapy against breast carcinoma

Three mono-hydroxy corroles 1-3 and their gallium(III) complexes Ga1-3 were synthesized, and their photodynamic antitumour activities towards breast cancer cells were investigated. All corroles showed excellent cytotoxicity against the MDA-MB-231 and 4T1 cell lines upon light irradiation at 625 nm. Ga3 exhibited excellent phototoxicity and selectivity against MDA-MB-231 cells, with an IC₅₀ of 0.06 ± 0.03 μM and a selective index value of 1338.83 (relative to human normal Huvec cells). The performance of Ga3 was even better than that of the clinical photodynamic therapy drug m-THPC. A preliminary mechanistic investigation revealed that corrole 3 and Ga3 were mainly located in the cytoplasm. Upon irradiation, they could generate intracellular reactive oxygen to destroy the mitochondrial membrane potential and arrest the cell cycle at the sub-G1 phase. Flow cytometry revealed that corrole 3 and Ga3 induced cancer cell apoptosis after photodynamic treatment. Corrole 3 and Ga3 displayed negligible cytotoxicity in the dark. These results suggest that corrole 3 and Ga3 are promising candidates for use in the photodynamic therapy of breast cancer.

Corroles and Hexaphyrins: Synthesis and Application in Cancer Photodynamic Therapy

Corroles and hexaphyrins are porphyrinoids with great potential for diverse applications. Like porphyrins, many of their applications are based on their unique capability to interact with light, i.e., based on their photophysical properties. Corroles have intense absorptions in the low-energy region of the uv-vis, while hexaphyrins have the capability to absorb light in the near-infrared (NIR) region, presenting photophysical features which are complementary to those of porphyrins. Despite the increasing interest in corroles and hexaphyrins in recent years, the full potential of both classes of compounds, regarding biological applications, has been hampered by their challenging synthesis. Herein, recent developments in the synthesis of corroles and hexaphyrins are reviewed, highlighting their potential application in photodynamic therapy.

Photophysical and electrochemical properties of two trans-A2B-corroles: differences between phenyl or pyrenyl groups at the meso-10 position

The photophysical properties of two meso–trans-A₂B-type corroles containing phenyl or pyrenyl units were reported in this study. TD-DFT calculations and electrochemical analysis were conducted to better understand the corrole molecular structures.