Multitarget-Directed Gallium(III) Tris(acyl-pyrazolonate) Complexes Induce Ferroptosis in Cancer Cells via Dysregulation of Cell Redox Homeostasis and Inhibition of the Mevalonate Pathway

A Λ-Ir(iii)-phenylquinazolinone complex enhances ferroptosis by selectively inhibiting metallothionein-1

Chirality plays an indispensable role in various biological processes, and interactions between chiral enantiomers and biomolecular targets provide new perspectives in precision drug development. While ferroptosis has received increasing attention as a novel pathway to reverse drug resistance, work on the design of precise ferroptosis-targeting molecules through chiral programming was limited. In this work, we designed and synthesized a pair of chirality-dependent ferroptosis-inducing Ir(iii)-phenylquinazolinone complexes (Δ-IrPPQ and Λ-IrPPQ) by inhibiting ferroptosis suppressor protein-1 (FSP1), while the pair of IrPPQ complexes induced extremely different ferroptosis effects as well as distinct photodynamic therapy (PDT) responses toward pancreatic cancer cells. Interestingly, this chirality-dependent biological mechanism through proteomic analysis and molecular simulation revealed that the specific binding and inhibition of metallothionein-1 (MT1) by Λ-IrPPQ sensitized cancer cells to ferroptosis, inducing a burst of reactive oxygen species, lipid peroxidation, glutathione depletion, and inactivation of FSP1. While in comparison, Δ-IrPPQ induced mild ferroptotic cell death. Through simple chiral resolution, the obtained Λ-IrPPQ achieved precise regulation of ferroptosis in pancreatic cancer cells. This work provides new insights into the design of chiral ferroptosis-inducing metallodrugs for future pancreatic cancer therapy.

Recent Progress in Ferroptosis Induced Tumor Cell Death by Anti-tumor Metallic complexes

Metal complexes represented by platinum complexes play a very important role in cancer treatment due to their diverse chemical structures and anti-tumor activities. Recently, ferroptosis has emerged as a newly occurring cell death form in the anti-tumor process. It has been reported that metal complexes could inhibit the proliferation and metastasis of tumors and combat chemotherapy resistance by targeting ferroptosis. In this review, we briefly describe ferroptosis as a fundamental process for tumor suppression and triggering anti-tumor immune responses. We summarize recent developments on metal complexes that induce ferroptosis. Finally, we outline the prospects for the application of metal complexes to the treatment of tumors based on ferroptosis and the associated problems that need to be solved, and discussed other potential research directions of metal complexes.

Yi-qi-hua-yu-jie-du decoction induces ferroptosis in cisplatin-resistant gastric cancer via the AKT/GSK3β/NRF2/GPX4 axis

BACKGROUND

Resistance to chemotherapy in gastric cancer (GC) is a ubiquitous challenge for its treatment. Yi-qi-hua-yu-jie-du decoction (YJD), an empirical formula in Traditional Chinese Medicine (TCM), demonstrated survival-prolonging functions in patients with GC. Previous research has shown that YJD could also inhibit drug resistance in GC. However, the precise mechanisms for how YJD accomplishes this remain incompletely explained.

PURPOSE

The research aimed to identify differential metabolic characteristics in cisplatin-resistant GC and investigate whether YJD can target these differences to suppress GC drug resistance.

METHODS

Metabolomic analysis was conducted to identify metabolic disparities between cisplatin-resistant and parental GC cells, as well as metabolic modifications resulting from YJD intervention in cisplatin-resistant GC cells. The effect of YJD on ferroptosis stimulation was assessed by measuring the levels of reactive oxygen species (ROS), malondialdehyde (MDA), iron ions, the reduced glutathione (GSH) to oxidised glutathione (GSSG) ratio, and alterations in mitochondrial morphology. Western blotting and quantitative real-time polymerase chain reaction (Q-PCR) were employed to verity the mechanisms of YJD-triggered ferroptosis through GPX4 and NRF2 overexpression models, alongside the AKT activator SC79. In vivo validation was conducted using nude mouse xenograft models.

RESULTS

Cisplatin-resistant GC exhibited altered GSH/GPX4 metabolism, and ferroptosis was a significantly enriched cell death pattern with YJD treatment in cisplatin-resistant GC cells. Ferroptosis biomarkers, including ROS, MDA, iron ions, the GSH/GSSG ratio, and mitochondrial morphology, were remarkably changed with the YJD intervention. Mechanistic experiments demonstrated that YJD inhibited the phosphorylation cascade activity of the AKT/GSK3β pathway, thereby reducing NRF2 expression. The level of GPX4, a crucial enzyme involved in glutathione metabolism, was attenuated, facilitating ferroptosis induction in cisplatin-resistant GC.

CONCLUSION

The research reveals, for the first time, changes in GSH/GPX4 metabolism in cisplatin-resistant GC cells based on metabolomic analysis. YJD induced ferroptosis in cisplatin-resistant GC by inhibiting GPX4 through the AKT/GSK3β/NRF2 pathway, thus attenuating the cisplatin drug resistance in GC. Our findings identify metabolic changes in cisplatin-resistant GC and establish a theoretical framework for YJD on tackling drug resistance in GC through ferroptosis.

Gallium-doped thermochemically treated titanium reduces osteoclastogenesis and improves osteodifferentiation

Excessive bone resorption is one of the main causes of bone homeostasis alterations, resulting in an imbalance in the natural remodeling cycle. This imbalance can cause diseases such as osteoporosis, or it can be exacerbated in bone cancer processes. In such cases, there is an increased risk of fractures requiring a prosthesis. In the present study, a titanium implant subjected to gallium (Ga)-doped thermochemical treatment was evaluated as a strategy to reduce bone resorption and improve osteodifferentiation. The suitability of the material to reduce bone resorption was proven by inducing macrophages (RAW 264.7) to differentiate to osteoclasts on Ga-containing surfaces. In addition, the behavior of human mesenchymal stem cells (hMSCs) was studied in terms of cell adhesion, morphology, proliferation, and differentiation. The results proved that the Ga-containing calcium titanate layer is capable of inhibiting osteoclastogenesis, hypothetically by inducing ferroptosis. Furthermore, Ga-containing surfaces promote the differentiation of hMSCs into osteoblasts. Therefore, Ga-containing calcium titanate may be a promising strategy for patients with fractures resulting from an excessive bone resorption disease.

Antitumor studies evaluation of triphenylphosphine ruthenium complexes with 5,7-dihalo-substituted-8-quinolinoline targeting mitophagy pathways

Both ruthenium-containing complexes and 8-quinolinoline compounds have emerged as a potential novel agent for malignant tumor therapy. Here, three triphenylphosphine ruthenium complexes, [Ru(ZW1)(PPh3)2Cl2] (PPh3 = triphenylphosphine) (RuZ1), [Ru(ZW2)(PPh3)2Cl2] (RuZ2) and [Ru(ZW2)2(PPh3)Cl2]·CH2Cl2 (RuZ3) bearing 5,7-dichloro-8-quinolinol (H-ZW1) and 5,7-dichloro-8-hydroxyquinaldine (H-ZW2), have been synthesized, characterized and tested for their anticancer potential. We showed that triphenylphosphine ruthenium complexes RuZ1-RuZ3 impaired the cell viability of ovarian adenocarcinoma cisplatin-resistant SK-OV-3/DDP (SKO3CR) and SK-OV-3 (SKO3) cancer cells with greater selectivity and specificity than cisplatin. In addition, RuZ1-RuZ3 show higher excellent cytotoxicity than cisplatin towards SKO3CR cells, with IC50 values of 9.66 ± 1.08, 4.05 ± 0.67 and 7.18 ± 0.40 μM, respectively, in which the SKO3CR cells was the most sensitive to RuZ1-RuZ3. Depending on the substituent type, the antiproliferative ability of RuZ1-RuZ3 followed the trend: -CH3 > -H. However, RuZ1-RuZ3 have no obvious toxicity to normal cell HL-7702. Besides, RuZ1 and RuZ2 could induce mitophagy related-apoptosis pathways through suppression of mitochondrial membrane potential (ΔΨm), accumulation of [Ca2+] and reactive oxygen species (ROS), and regulation of LC3 II/LC3 I, Beclin-1, P62, FUNDC1, PINK1, Parkin, cleaved-caspase-3, caspase-9 and cytochrome c signaling pathway, and hindering the preparation of mitochondrial respiration complexes I and IV and ATP levels. Mechanistic study revealed that RuZ1 and RuZ2 induce apoptosis in SKO3CR cells via mitophagy related-apoptosis pathways induction and energy (ATP) generation disturbance. Taken together, the studied triphenylphosphine ruthenium complexes RuZ1-RuZ3 are promising chemotherapeutic agents with high effectiveness and low toxicity.

Gallium Triggers Ferroptosis through a Synergistic Mechanism

The gallium ion (Ga3+ ) has long been believed to disrupt ferric homeostasis in the body by competing with iron cofactors in metalloproteins, ultimately leading to cell death. This study revealed that through an indirect pathway, gallium can trigger ferroptosis, a type of non-apoptotic cell death regulated by iron. This is exemplified by the gallium complex of the salen ligand (Ga-1); we found that Ga-1 acts as an effective anion transporter that can affect the pH gradient and change membrane permeability, leading to mitochondrial dysfunction and the release of ferrous iron from the electron transfer chain (ETC). In addition, Ga-1 also targeted protein disulfide isomerases (PDIs) located in the endoplasmic reticulum (ER) membrane, preventing the repair of the antioxidant glutathione (GSH) system and thus enforcing ferroptosis. Finally, a combination treatment of Ga-1 and dietary polyunsaturated fatty acids (PUFAs), which enhances lipid peroxidation during ferroptosis, showed a synergistic therapeutic effect both in vitro and in vivo. This study provided us with a strategy to synergistically induce Ferroptosis in tumor cells, thereby enhancing the anti-neoplastic effect.