Indium/Gallium Maltolate Effects on Human Breast Carcinoma Cells: In Vitro Investigation on Cytotoxicity and Synergism with Mitoxantrone

In(III) pyridinecarboxylate complexes: Composition, solution equilibria estimation, bioevaluation and interactions with HSA

Two In(III) - pyridinecarboxylates ([In(Pic)2(NO3)(H2O)] (InPic; HPic = picolinic acid), [In(HDpic)(Dpic)(H2O)2]·5H2O (InDpic; H2Dpic = dipicolinic acid), have been synthesized by one-step procedure. The complexes composition was confirmed by physicochemical analyses and X-ray diffraction confirmed molecular structure of both complexes. Moreover, complex species speciation was described in both systems by potentiometry and 1H NMR spectroscopy and mononuclear complex species were determined; [In(Pic)]2+ (logβ011 = 6.94(4)), [In(Pic)2]+ (logβ021 = 11.98(9)), [In(Dpic)]+ (logβ011 = 10.42(6)), [In(Dpic)2]- (logβ021 = 17.58(7)) and [In(Dpic)2(OH)]2- (logβ-121 = 10.18(6)). To confirm the complexes stability in 1 % DMSO, 1H NMR spectra were measured (immediately after dissolution up to 96 h). Antimicrobial and anticancer assays indicate a more significant sensitivity of S. aureus bacteria and MDA-MB-231 cancer cells to the InPic complex (IC50 = 25 and 340.7 μM) than to the InDpic (IC50 = 50 and 975.4 μM). The interaction and binding mechanism of picolinic/dipicolinic acid and their indium(III) complexes with HSA (human serum albumin) were studied using fluorescence and CD spectroscopy. The results confirmed that the studied compounds had bound successfully to HSA, and the binding parameters and constants (KSV, Kq, Kb) were calculated together with the number of binding sites. The binding forces were identified based on calculated thermodynamic parameters (ΔG, ΔH, ΔS). Synchronous spectra were used to study the microenvironment of Tyr and Trp residues and displacement assays revealed that site I was the preferred binding site. After binding, conformational changes were found to have occurred in the HSA molecule and the % α-helical content had decreased.

Gallium maltolate shows synergism with cisplatin and activates nucleolar stress and ferroptosis in human breast carcinoma cells

PURPOSE

Breast cancer is the most common cancer in women. Triple-negative breast cancer (TNBC) is an aggressive disease with poor outcomes. TNBC lacks effective targeted treatments, and the development of drug resistance limits the effectiveness of chemotherapy. It is crucial to identify new drugs that can enhance the efficacy of traditional chemotherapy to reduce drug resistance and side effects.

METHODS

TNBC cell lines, MDA-MB-231 and Hs 578T, and a normal cell line, MCF-10 A, were included in this study. The cells were treated with gallium maltolate (GaM), and their transcriptome was analyzed. Ferroptosis and nucleolar stress markers were detected by qPCR, western blotting, fluorescence microscopy, and flow cytometry. The impairment of ribosome synthesis was evaluated by northern blotting and sucrose gradients.

RESULTS

GaM triggered cell death via apoptosis and ferroptosis. In addition, GaM impaired translation and activated nucleolar stress. Cisplatin (DDP) is a chemotherapeutic agent for advanced breast cancer. While single treatment with GaM or DDP at low concentrations did not impact cell growth, co-administration enhanced cell death in TNBC but not in normal breast cells. The enhancement of ferroptosis and nucleolar stress could be observed in TNBC cell lines after co-treatment.

CONCLUSIONS

These results suggest that GaM synergizes with cisplatin via activation of nucleolar stress and ferroptosis in human breast carcinoma cells. GaM is marginally toxic to normal cells but impairs the growth of TNBC cell lines. Thus, GaM has the potential to be used as a therapeutic agent against TNBC.

Deferiprone and Iron-Maltol: Forty Years since Their Discovery and Insights into Their Drug Design, Development, Clinical Use and Future Prospects

The historical insights and background of the discovery, development and clinical use of deferiprone (L1) and the maltol-iron complex, which were discovered over 40 years ago, highlight the difficulties, complexities and efforts in general orphan drug development programs originating from academic centers. Deferiprone is widely used for the removal of excess iron in the treatment of iron overload diseases, but also in many other diseases associated with iron toxicity, as well as the modulation of iron metabolism pathways. The maltol-iron complex is a recently approved drug used for increasing iron intake in the treatment of iron deficiency anemia, a condition affecting one-third to one-quarter of the world's population. Detailed insights into different aspects of drug development associated with L1 and the maltol-iron complex are revealed, including theoretical concepts of invention; drug discovery; new chemical synthesis; in vitro, in vivo and clinical screening; toxicology; pharmacology; and the optimization of dose protocols. The prospects of the application of these two drugs in many other diseases are discussed under the light of competing drugs from other academic and commercial centers and also different regulatory authorities. The underlying scientific and other strategies, as well as the many limitations in the present global scene of pharmaceuticals, are also highlighted, with an emphasis on the priorities for orphan drug and emergency medicine development, including the roles of the academic scientific community, pharmaceutical companies and patient organizations.

Gallium and indium complexes with isoniazid-derived ligands: Interaction with biomolecules and biological activity against cancer cells and Mycobacterium tuberculosis

Gallium and indium octahedral complexes with isoniazid derivative ligands were successfully prepared. The ligands, isonicotinoyl benzoylacetone (H₂L¹) and 4-chlorobenzoylacetone isonicotinoyl hydrazone (H₂L²), and their respective coordination compounds with gallium and indium [GaL¹(HL¹)] (GaL¹), [GaL²(HL²)] (GaL²), [InL¹(HL¹)] (InL¹) and [InL²(HL²)] (InL²) were investigated by NMR, ESI-MS, UV-Vis, IR, single-crystal X-ray diffraction and elemental analysis. In vitro interaction studies with human serum albumin (HSA) evidenced a moderate affinity of all complexes with HSA through spontaneous hydrophobic interactions. The greatest suppression of HSA fluorescence was caused by GaL² and InL², which was associated to the higher lipophilicity of H₂L². In vitro interaction studies with CT-DNA indicated weak interactions of the biomolecule with all complexes. Cytotoxicity assays with MCF-7 (breast carcinoma), PC-3 (prostate carcinoma) and RWPE-1 (healthy human prostate epithelial) cell lines showed that complexes with H₂L² are more active and selective against MCF-7, with the greatest cytotoxicity observed for InL² (IC₅₀ = 10.34 ± 1.69 μM). H₂L¹ and H₂L² were labelled with gallium-67, and it was verified that ⁶⁷GaL² has a greater lipophilicity than ⁶⁷GaL¹, as well as higher stability in human serum or in the presence of apo-transferrin. Cellular uptake assays with ⁶⁷GaL¹ and ⁶⁷GaL² evidenced that the H₂L²-containing radiocomplex has a higher accumulation in MCF-7 and PC-3 cells than the non-halogenated congener ⁶⁷GaL¹. The anti-Mycobacterium tuberculosis assays revealed that both ligands and metal complexes are potent growth inhibitors, with MIC₉₀ (μg mL^-1) values observed from 0.419 ± 0.05 to 1.378 ± 0.21.

In vitro and in vivo studies of a newly synthesized copper-cetyl tri-methyl ammonium bromide combined with gallium oxide nanoparticles complex as an antitumor agent against hepatocellular carcinoma

Objective: Hepatocellular carcinoma (HCC) is one of the most leading causes of death worldwide. Previous studies reported that gallium alone and cetyltrimethylammonium bromide (CTAB) have antineoplastic activities; therefore, this study aimed to evaluate the activity of copper-cetyl tri-methyl ammonium bromide with gallium oxide nanoparticles (Cu-CTAB+GaO-NPs) against HCC by using in vitro and in vivo studies. Methods: In vitro study was performed to evaluate the cytotoxic effects of Cu-CTAB+GaO-NPs and GaO-NPs on HepG-2 cell line using crystal violet dye assay. In vivo study was done on diethyl nitrosamine (DEN) induced HCC Wister rats. Rats were randomly divided into eight groups; control, Cu-CTAB, GaO-NPs, Cu-CTAB+GaONPs, DEN, DEN+Cu-CTAB, DEN+GaO-NPs and DEN+Cu-CTAB+GaO-NPs. Histopathological examination of liver and biochemical parameters such as liver function markers, oxidative stress-antioxidants markers, tumor makers, apoptosis makers were studied. Results: Results obtained from in vitro study revealed that Cu-CTAB+GaO-NPs and GaO-NPs affect the cell viability of HepG-2 cancer cell with IC50 0.2 μg/ml and 360 μg/ml, respectively. Cu-CTAB+GaO-NPs exerted an antiproliferative effect in experimental rat models of HCC, as demonstrated both histologically, since it facilitated the tissue recovery of the damaged liver, and biochemically as showed by the reduction of liver function markers (ALT & AST), oxidative stress markers (MDA) and tumor makers (AFP,TGF-β1,α-L-Fucosidase); while antioxidants markers (SOD), apoptosis markers (caspase-3 mRNA) and araginase activity were elevated in DEN+Cu-CTAB, DEN+GaO-NPs and DEN+Cu-CTAB+GaO-NPs groups when compared to DEN group. Conclusion: The present study demonstrated that both Cu-CTAB alone and/or combined with GaO-NPs exerted cytotoxic effects against DEN-induced HCC, which would in turn, speculate a possible therapeutic role of the novel Cu-CTAB+GaO-NPs compound.

Solution speciation and human serum protein binding of indium(III) complexes of 8-hydroxyquinoline, deferiprone and maltol

Solution speciation and serum protein binding of selected In(III) complexes bearing O,O and O,N donor sets were studied to provide comparative data for In(III) and analogous Ga(III) complexes. Aqueous stability of the In(III) complexes of maltol, deferiprone, 8-hydroxyquinoline (HQ) and 8-hydroxyquinoline-5-sulfonate (HQS) was characterized by a combined pH-potentiometric and UV-visible spectrophotometric approach. Formation of mono, bis and tris-ligand complexes was observed. The tris-ligand complexes of HQ (InQ3) and deferiprone (InD3) are present in solution in ca. 90% at 10 µM concentration at pH = 7.4, while the tris-maltolato complex (InM3) displays insufficient stability under these conditions. Binding towards human serum albumin (HSA) and (apo)transferrin ((apo)Tf) of InQ3, InD3 and InM3 complexes and Ga(III) analogue of InQ3 (GaQ3) together with InCl3 was investigated by a panel of methods: steady-state and time-resolved spectrofluorometry, UV-visible spectrophotometry and membrane ultrafiltration. Moderate binding of InQ3 to HSA was found (log K' = 5.0-5.1). InD3 binds to HSA to a much lower extent in comparison to InQ3. ApoTf is able to displace HQ, deferiprone and maltol effectively from their In(III) complexes. Protein binding of non-dissociated InQ3 was also observed at high complex-to-apoTf ratios. Studies conducted with the InQ3/GaQ3 - HSA - Tf ternary systems revealed the more pronounced Tf binding of In(III) via ligand release, while the original GaQ3 scaffold is preferably retained upon protein interactions and significant albumin binding occurs. Significant dissociation of InQ3 was detected in human blood serum as well.

New Era in the Treatment of Iron Deficiency Anaemia Using Trimaltol Iron and Other Lipophilic Iron Chelator Complexes: Historical Perspectives of Discovery and Future Applications

The trimaltol iron complex (International Non-proprietary Name: ferric maltol) was originally designed, synthesised, and screened in vitro and in vivo in 1980–1981 by Kontoghiorghes G.J. following his discovery of the novel alpha-ketohydroxyheteroaromatic (KHP) class of iron chelators (1978–1981), which were intended for clinical use, including the treatment of iron deficiency anaemia (IDA). Iron deficiency anaemia is a global health problem affecting about one-third of the world’s population. Many (and different) ferrous and ferric iron complex formulations are widely available and sold worldwide over the counter for the treatment of IDA. Almost all such complexes suffer from instability in the acidic environment of the stomach and competition from other dietary molecules or drugs. Natural and synthetic lipophilic KHP chelators, including maltol, have been shown in in vitro and in vivo studies to form stable iron complexes, to transfer iron across cell membranes, and to increase iron absorption in animals. Trimaltol iron, sold as Feraccru or Accrufer, was recently approved for clinical use in IDA patients in many countries, including the USA and in EU countries, and was shown to be effective and safe, with a better therapeutic index in comparison to other iron formulations. Similar properties of increased iron absorption were also shown by lipophilic iron complexes of 8-hydroxyquinoline, tropolone, 2-hydroxy-4-methoxypyridine-1-oxide, and related analogues. The interactions of the KHP iron complexes with natural chelators, drugs, metal ions, proteins, and other molecules appear to affect the pharmacological and metabolic effects of both iron and the KHP chelators. A new era in the treatment of IDA and other possible clinical applications, such as theranostic and anticancer formulations and metal radiotracers in diagnostic medicine, are envisaged from the introduction of maltol, KHP, and similar lipophilic chelators.

Extra-Small Gold Nanospheres Decorated With a Thiol Functionalized Biodegradable and Biocompatible Linear Polyamidoamine as Nanovectors of Anticancer Molecules

Gold nanoparticles are elective candidate for cancer therapy. Current efforts are devoted to developing innovative methods for their synthesis. Besides, understanding their interaction with cells have become increasingly important for their clinical application. This work aims to describe a simple approach for the synthesis of extra-small gold nanoparticles for breast cancer therapy. In brief, a biocompatible and biodegradable polyamidoamine (named AGMA1-SH), bearing 20%, on a molar basis, thiol-functionalized repeat units, is employed to stabilize and coat extra-small gold nanospheres of different sizes (2.5, 3.5, and 5 nm in gold core), and to generate a nanoplatform for the link with Trastuzumab monoclonal antibody for HER2-positive breast cancer targeting. Dynamic light scattering, transmission electron microscopy, ultraviolet visible spectroscopy, X-ray powder diffraction, circular dichroism, protein quantification assays are used for the characterization. The targeting properties of the nanosystems are explored to achieve enhanced and selective uptake of AGMA1-SH-gold nanoparticles by in vitro studies against HER-2 overexpressing cells, SKBR-3 and compared to HER-2 low expressing cells, MCF-7, and normal fibroblast cell line, NIH-3T3. In vitro physicochemical characterization demonstrates that gold nanoparticles modified with AGMA1-SH are more stable in aqueous solution than the unmodified ones. Additionally, the greater gold nanoparticles size (5-nm) is associated with a higher stability and conjugation efficiency with Trastuzumab, which retains its folding and anticancer activity after the conjugation. In particular, the larger Trastuzumab functionalized nanoparticles displays the highest efficacy (via the pro-apoptotic protein increase, anti-apoptotic components decrease, survival-proliferation pathways downregulation) and internalization (via the activation of the classical clathrin-mediated endocytosis) in HER-2 overexpressing SKBR-3 cells, without eliciting significant effects on the other cell lines. The use of biocompatible AGMA1-SH for producing covalently stabilized gold nanoparticles to achieve selective targeting, cytotoxicity and uptake is completely novel, offering an important advancement for developing new anticancer conjugated-gold nanoparticles.