Functionalization of Platinum Complexes for Biomedical Applications

Identification of mitochondrial ATP synthase as the cellular target of Ru-polypyridyl--carboline complexes by affinity-based protein profiling

Ruthenium polypyridyl complexes are promising anticancer candidates, while their cellular targets have rarely been identified, which limits their clinical application. Herein, we design a series of Ru(II) polypyridyl complexes containing bioactive β-carboline derivatives as ligands for anticancer evaluation, among which Ru5 shows suitable lipophilicity, high aqueous solubility, relatively high anticancer activity and cancer cell selectivity. The subsequent utilization of a photo-clickable probe, Ru5a, serves to validate the significance of ATP synthase as a crucial target for Ru5 through photoaffinity-based protein profiling. Ru5 accumulates in mitochondria, impairs mitochondrial functions and induces mitophagy and ferroptosis. Combined analysis of mitochondrial proteomics and RNA-sequencing shows that Ru5 significantly downregulates the expression of the chloride channel protein, and influences genes related to ferroptosis and epithelial-to-mesenchymal transition. Finally, we prove that Ru5 exhibits higher anticancer efficacy than cisplatin in vivo. We firstly identify the molecular targets of ruthenium polypyridyl complexes using a photo-click proteomic method coupled with a multiomics approach, which provides an innovative strategy to elucidate the anticancer mechanisms of metallo-anticancer candidates.

Highly cytotoxic Cu(II) terpyridine complexes as chemotherapeutic agents

Cancer is considered as the biggest medicinal challenge worldwide. During a typical treatment, the tumorous tissue is removed in a surgical procedure and the patient further treated by chemotherapy. One of the most frequently applied drugs are platinum complexes. Despite their clinical success, these compounds are associated with severe side effects and low therapeutic efficiency. To overcome these limitations, herein, the synthesis and biological evaluation of Cu(II) terpyridine complexes as chemotherapeutic drug candidates is suggested. The compounds were found to be highly cytotoxic in the nanomolar range against various cancer cell lines. Mechanistic insights revealed that the compounds primarily accumulated in the cytoplasm and generated reactive oxygen species in this organelle, triggering cell death by apoptosis. Based on their high therapeutic effect, these metal complexes could serve as a starting point for further drug development.

Recently Reported Biological Activities and Action Targets of Pt(II)- and Cu(II)-Based Complexes

Most diseases that affect human beings across the world are now treated with drugs of organic origin. However, some of these are associated with side effects, toxicity, and resistance phenomena. For the treatment of many illnesses, the development of new molecules with pharmacological potential is now an urgent matter. The biological activities of metal complexes have been reported to have antitumor, antimicrobial, anti-inflammatory, anti-infective and antiparasitic effects, amongst others. Metal complexes are effective because they possess unique properties. For example, the complex entity possesses the effective biological activity, then the formation of coordination bonds between the metal ions and ligands is controlled, metal ions provide it with extraordinary mechanisms of action because of characteristics such as d-orbitals, oxidation states, and specific orientations; metal complexes also exhibit good stability and good physicochemical properties such as water solubility. Platinum is a transition metal widely used in the design of drugs with antineoplastic activities; however, platinum is associated with side effects which have made it necessary to search for, and design, novel complexes based on other metals. Copper is a biometal which is found in living systems; it is now used in the design of metal complexes with biological activities that have demonstrated antitumoral, antimicrobial and anti-inflammatory effects, amongst others. In this review, we consider the open horizons of Cu(II)- and Pt(II)-based complexes, new trends in their design, their synthesis, their biological activities and their targets of action.

A monofunctional Pt(II) complex combats triple negative breast cancer by triggering lysosome-dependent cell death

Monofunctional Pt(II) complexes with potent efficacy to overcome the drawbacks of current platinum drugs represent a promising therapeutic approach for triple negative breast cancer (TNBC). A heterocyclic-ligated monofunctional Pt(II) complex PtL with a unique action of mode was designed and investigated. PtL induced DNA single-strand breaks and caused genomic instability in TNBC cells. Mechanism studies demonstrated that PtL disrupted lysosomal acidity and function, which in turn triggered lysosome-dependent cell death. Furthermore, PtL showed convincing suppression in the tube forming and cell migratory abilities against the metastatic potential of TNBC cells. The synthesis and investigation of PtL revealed its potential value as an anti-TNBC drug and extended the family of monofunctional Pt(II) complexes.

Development of Platinum Complexes for Tumor Chemoimmunotherapy

Platinum complexes are potential antitumor drugs in chemotherapy. Their impact on tumor treatment could be greatly strengthened by combining with immunotherapy. Increasing evidences indicate that the antitumor activity of platinum complexes is not limited to chemical killing effects, but also extends to immunomodulatory actions. This review introduced the general concept of chemoimmunotherapy and summarized the progress of platinum complexes as chemoimmunotherapeutic agents in recent years. Platinum complexes could be developed into inducers of immunogenic cell death, blockers of immune checkpoint, regulators of immune signaling pathway, and modulators of tumor immune microenvironment, etc. The synergy between chemotherapeutic and immunomodulatory effects reinforces the antitumor activity of platinum complexes, and helps them circumvent the drug resistance and systemic toxicity. The exploration of platinum complexes for chemoimmunotherapy may create new opportunities to revive the discovery of metal anticancer drugs.

Configurationally regulated half-sandwich iridium(III)-ferrocene heteronuclear metal complexes: Potential anticancer agents

Half-sandwich iridium(III) (IrIII) complexes and ferrocenyl (Fc) derivatives are becoming the research hotspot in the field of anticancer because of their good bioactivity and unique anticancer mechanism different from platinum-based drugs. Then, a series of half-sandwich IrIII-Fc pyridine complexes have been prepared through the structural regulation in this study. The incorporation of half-sandwich IrIII complex with Fc unit successfully improves their anticancer activity, and the optimal performance (IrFc5) is almost 3-fold higher than that of cisplatin against A549 cells, meanwhile, which also shows better anti-proliferative activity against A549/DDP cells. Complexes can aggregate in the intracellular lysosome of A549 cells and induce lysosomal damage, disrupt the cell cycle, increase the level of intracellular reactive oxygen species, and eventually lead to cell apoptosis. Half-sandwich IrIII-Fc heteronuclear metal complexes possess a different anticancer mechanism from cisplatin, which can serve as a potential alternative to platinum-based drugs and show a good application prospect.

Cationic N,S-chelate half-sandwich iridium complexes: synthesis, characterization, anticancer and antiplasmodial activity

A series of pyrazole-based ligands and their corresponding cationic N,S-chelate half-sandwich iridium complexes were successfully synthesized. All iridium complexes exhibited good anticancer activity against the MCF-7 and MDA-MB-231 human breast cancer cells. The cytotoxic activity of unsubstituted iridium complex 1 is greater than that of cisplatin against MCF-7 cells. In addition, the cationic half-sandwich iridium complexes are also efficient in antiplasmodial study and complex 1 displayed the best activity as its IC50 was observed to be approximately 0.11 μM against the CQS-NF54 strain. These iridium complexes generally exhibited enhanced activity against the CQS-NF54 strain in comparison with that against the CQR-K1 strain. An "IC50 speed assay" investigation against the CQS-NF54 strain indicated complexes 1-3 to be fast-acting complexes that reach their lowest IC50 values within 16 hours. All complexes were fully characterized by IR spectroscopy, NMR spectroscopy, and elemental analysis, and the structure of the iridium complex was confirmed by single-crystal X-ray diffraction.

Advance in integrating platinum-based chemotherapy with radiotherapy for locally advanced nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant tumor characterized by the malignant transformation of nasopharyngeal epithelial cells. It is highly sensitive to radiation therapy, making radiotherapy the primary treatment modality. However, 60-80% of patients are initially diagnosed with locally advanced NPC (LA-NPC), where radiotherapy alone often fails to achieve desirable outcomes. Therefore, combining radiotherapy with chemotherapy has emerged as an effective strategy to optimize treatment for LA-NPC patients. Among the various chemotherapy regimens, concurrent chemoradiotherapy (CCRT) using platinum-based drugs has been established as the most commonly utilized approach for LA-NPC patients. The extensive utilization of platinum drugs in clinical settings underscores their therapeutic potential and emphasizes ongoing efforts in the development of novel platinum-based complexes for anticancer therapy. The aim of this review is to elucidate the remarkable advances made in the field of platinum-based therapies for nasopharyngeal carcinoma, emphasizing their transformative impact on patient prognosis.

Polysaccharide‑platinum complexes for cancer theranostics

Platinum anticancer drugs have been explored and developed in recent years to reduce systematic toxicities and resist drug resistance. Polysaccharides derived from nature have abundant structures as well as pharmacological activities. The review provides insights on the design, synthesis, characterization and associating therapeutic application of platinum complexes with polysaccharides that are classified by electronic charge. The complexes give birth to multifunctional properties with enhanced drug accumulation, improved tumor selectivity and achieved synergistic antitumor effect in cancer therapy. Several techniques developing polysaccharides-based carriers newly are also discussed. Moreover, the lasted immunoregulatory activities of innate immune reactions triggered by polysaccharides are summarized. Finally, we discuss the current shortcomings and outline potential strategies for improving platinum-based personalized cancer treatment. Using platinum-polysaccharides complexes for improving the immunotherapy efficiency represents a promising framework in future.

Veratricplatin inhibits the progression of hypopharyngeal squamous cell carcinoma FaDu cells in vitro and in vivo

PURPOSE

Head and neck squamous cell carcinoma (HNSCC) ranks as the sixth most prevalent cancer. In recent years, the modification of platinum(II) into platinum(IV) derivative compounds, by introducing biologically active molecules, has been extensively employed to develop novel platinum-based prodrugs. We investigated the anti-proliferative activity against HNSCC of a new veratric acid (COX-2 inhibitor)-platinum(IV) complex.

METHODS

In this study, a new veratric acid (COX-2 inhibitor)-platinum(IV) complex, termed veratricplatin, was synthesized. We evaluated the anti-tumor effect of in vitro and in vivo by western blotting, flow cytometry and DNA damage analysis.

RESULTS

Veratricplatin displayed remarkable anti-proliferative activity against various cancer cell lines, including A549, FaDu, HeLa, and MCF-7. Furthermore, veratricplatin demonstrated significantly stronger cytotoxicity than either platinum(II) or veratric acid monotherapy or their combination. Importantly, the synthesized prodrug exhibited less toxicity toward normal cells (MRC-5), while dramatically enhanced DNA damage in FaDu cells inducing apoptosis. Moreover, veratricplatin markedly reduced the migration ability of FaDu cells compared to the control or monotherapy. In vivo, veratricplatin displayed potent anti-tumor activity with no apparent toxicity in BALB/c nude mice bearing FaDu tumors. In addition, tissue immunofluorescence analysis revealed that veratricplatin could substantially inhibit the formation of tumor blood vessels.

CONCLUSION

Veratricplatin demonstrated remarkable drug efficacy, in terms of increased cytotoxicity in vitro and high efficiency with low toxicity in vivo.

Biomedical,clinical and environmental applications of platinum-based nanohybrids: An updated review

Platinum nanoparticles (Pt NPs) have numerous applications in various sectors, including pharmacology, nanomedicine, cancer therapy, radiotherapy, biotechnology and environment mitigation like removal of toxic metals from wastewater, photocatalytic degradation of toxic compounds, adsorption, and water splitting. The multifaceted applications of Pt NPs because of their ultra-fine structures, large surface area, tuned porosity, coordination-binding, and excellent physiochemical properties. The various types of nanohybrids (NHs) of Pt NPs can be fabricated by doping with different metal/metal oxide/polymer-based materials. There are several methods to synthesize platinum-based NHs, but biological processes are admirable because of green, economical, sustainable, and non-toxic. Due to the robust physicochemical and biological characteristics of platinum NPs, they are widely employed as nanocatalyst, antioxidant, antipathogenic, and anticancer agents. Indeed, Pt-based NHs are the subject of keen interest and substantial research area for biomedical and clinical applications. Hence, this review systematically studies antimicrobial, biological, and environmental applications of platinum and platinum-based NHs, predominantly for treating cancer and photo-thermal therapy. Applications of Pt NPs in nanomedicine and nano-diagnosis are also highlighted. Pt NPs-related nanotoxicity and the potential and opportunity for future nano-therapeutics based on Pt NPs are also discussed.

Docking Studies, Cytotoxicity Evaluation and Interactions of Binuclear Copper(II) Complexes with S-Isoalkyl Derivatives of Thiosalicylic Acid with Some Relevant Biomolecules

The numerous side effects of platinum based chemotherapy has led to the design of new therapeutics with platinum replaced by another transition metal. Here, we investigated the interactions of previously reported copper(II) complexes containing S-isoalkyl derivatives, the salicylic acid with guanosine-5'-monophosphate and calf thymus DNA (CT-DNA) and their antitumor effects, in a colon carcinoma model. All three copper(II) complexes exhibited an affinity for binding to CT-DNA, but there was no indication of intercalation or the displacement of ethidium bromide. Molecular docking studies revealed a significant affinity of the complexes for binding to the minor groove of B-form DNA, which coincided with DNA elongation, and a higher affinity for binding to Z-form DNA, supporting the hypothesis that the complex binding to CT-DNA induces a local transition from B-form to Z-form DNA. These complexes show a moderate, but selective cytotoxic effect toward colon cancer cells in vitro. Binuclear complex of copper(II) with S-isoamyl derivative of thiosalicylic acid showed the highest cytotoxic effect, arrested tumor cells in the G2/M phase of the cell cycle, and significantly reduced the expression of inflammatory molecules pro-IL-1β, TNF-α, ICAM-1, and VCAM-1 in the tissue of primary heterotopic murine colon cancer, which was accompanied by a significantly reduced tumor growth and metastases in the lung and liver.

Therapy and diagnosis of Alzheimer's disease: from discrete metal complexes to metal-organic frameworks

Alzheimer's disease (AD) is a neurodegenerative disorder affecting 44 million people worldwide. Although many issues (pathogenesis, genetics, clinical features, and pathological aspects) are still unknown, this disease is characterized by noticeable hallmarks such as the formation of β-amyloid plaques, hyperphosphorylation of tau proteins, the overproduction of reactive oxygen species, and the reduction of acetylcholine levels. There is still no cure for AD and the current treatments are aimed at regulating the cholinesterase levels, attenuating symptoms temporarily rather than preventing the AD progression. In this context, coordination compounds are regarded as a promissing tool in AD treatment and/or diagnosis. Coordination compounds (discrete or polymeric) possess several features that make them an interesting option for developing new drugs for AD (good biocompatibility, porosity, synergetic effects of ligand-metal, fluorescence, particle size, homogeneity, monodispersity, etc.). This review discusses the recent progress in the development of novel discrete metal complexes and metal-organic frameworks (MOFs) for the treatment, diagnosis and theragnosis of AD. These advanced therapies for AD treatment are organized according to the target: Aβ peptides, hyperphosphorylated tau proteins, synaptic dysfunction, and mitochondrial failure with subsequent oxidative stress.

From the Discovery of Targets to Delivery Systems: How to Decipher and Improve the Metallodrugs' Actions at a Molecular Level

Metals are indispensable for the life of all organisms, and their dysregulation leads to various disorders due to the disruption of their homeostasis. Nowadays, various transition metals are used in pharmaceutical products as diagnostic and therapeutic agents because their electronic structure allows them to adjust the properties of molecules differently from organic molecules. Therefore, interest in the study of metal-drug complexes from different aspects has been aroused, and numerous approaches have been developed to characterize, activate, deliver, and clarify molecular mechanisms. The integration of these different approaches, ranging from chemoproteomics to nanoparticle systems and various activation strategies, enables the understanding of the cellular responses to metal drugs, which may form the basis for the development of new drugs and/or the modification of currently used drugs. The purpose of this review is to briefly summarize the recent advances in this field by describing the technological platforms and their potential applications for identifying protein targets for discovering the mechanisms of action of metallodrugs and improving their efficiency during delivery.

Naphthalene Diimide-Functionalized Half-Sandwich Ru(II) Complexes as Mitochondria-Targeted Anticancer and Antimetastatic Agents

In this work, four naphthalene diimide (NDI)-functionalized half-sandwich Ru(II) complexes Ru1-Ru4 bearing the general formula [(η⁶-arene)Ru^II(N^N)Cl]PF₆, where arene = benzene (bn), p-cymene (p-cym), 1,3,5-trimethylbenzene (tmb), and hexamethylbenzene (hmb), have been synthesized and characterized. By introducing the NDI unit into the N,N-chelating ligand of these half-sandwich complexes, the poor luminescent half-sandwich complexes are endowed with excellent emission performance. Besides, modification on the arene ligand of arene-Ru(II) complexes can influence the electron density of the metal center, resulting in great changes in the kinetic properties, catalytic activities in the oxidative conversion of NADH to NAD⁺, and biological activities of these compounds. Particularly, Ru4 exhibits the highest reactivity and the strongest inhibitory activity against the growth of three tested cancer cell lines. Further study revealed that Ru4 can enter cells quickly in an energy-dependent manner and preferentially accumulate in the mitochondria of MDA-MB-231 cells, inducing cell apoptosis via reactive oxygen species overproduction and mitochondrial dysfunction. Significantly, Ru4 can effectively inhibit the cell migration and invasion. Overall, the complexation with NDI and modification on the arene ligand endowed the half-sandwich Ru(II) complexes with improved spectroscopic properties and anticancer activities, highlighting their potential applications for cancer treatment.

Platinum Drug-Incorporating Polymeric Nanosystems for Precise Cancer Therapy

Platinum (Pt) drugs are widely used in clinic for cancer therapy, but their therapeutic outcomes are significantly compromised by severe side effects and acquired drug resistance. With the emerging immunotherapy and imaging-guided cancer therapy, precise delivery and release of Pt drugs have drawn great attention these days. The targeting delivery of Pt drugs can greatly increase the accumulation at tumor sites, which ultimately enhances antitumor efficacy. Further, with the combination of Pt drugs and other theranostic agents into one nanosystem, it not only possesses excellent synergistic efficacy but also achieves real-time monitoring. In this review, after the introduction of Pt drugs and their characteristics, the recent progress of polymeric nanosystems for efficient delivery of Pt drugs is summarized with an emphasis on multi-modal synergistic therapy and imaging-guided Pt-based cancer treatment. In the end, the conclusions and future perspectives of Pt-encapsulated nanosystems are given.

Platinum(II) 5-substituted-8-hydroxyquinoline coordination compounds induces mitophagy-mediated apoptosis in A549/DDP cancer cells

For the first time, two new mononuclear platinum(II) coordination compounds, [Pt(L1)(DMSO)Cl] (PtL1) and [Pt(L2)(DMSO)Cl] (PtL2) with the 5-(ethoxymethyl)-8-hydroxyquinoline hydrochloride (H-L1) and 5-bromo-8-hydroxyquinoline (H-L2) have been synthesized and characterized. The cytotoxic activity of PtL1 and PtL2 were screened in both healthy HL-7702 cell line and cancer cell lines, human lung adenocarcinoma A549 cancer cells and cisplatin-resistant lung adenocarcinoma A549/DDP cancer cells (A549R), and were compared to that of the H-L1, H-L2, H-L3 ligands and 8-hydroxyquinoline (H-L3) platinum(II) complex [Pt(L3)(DMSO)Cl] (PtL3). MTT results showed that PtL1 bearing one deprotonated L1 ligand against A549R was more potent by 8.8-48.6 fold than that of PtL2 and PtL3 complexes but was more selective toward healthy HL-7702 cells. In addition, PtL1 and PtL3 overcomes tumour drug resistance by significantly inducing mitophagy and causing the change of the related proteins expression, which leads to cell apoptosis. Moreover, the inhibitory effect of PtL1 on A549 xenograft tumour was 68.2%, which was much higher than that of cisplatin (cisPt, ca. 50.0%), without significantly changing nude mice weight in comparison with the untreated group. This study helps to explore the potential of the platinum(II) 5-substituted-8-hydroxyquinoline coordination compounds for the new Pt-resistant cancer therapy.

Regorafenib and Ruthenium Complex Combination Inhibit Cancer Cell Growth by Targeting PI3K/AKT/ERK Signalling in Colorectal Cancer Cells

Cancer is one of the leading cause of lethality worldwide, CRC being the third most common cancer reported worldwide, with 1.85 million cases and 850,000 deaths annually. As in all other cancers, kinases are one of the major enzymes that play an essential role in the incidence and progression of CRC. Thus, using multi-kinase inhibitors is one of the therapeutic strategies used to counter advanced-stage CRC. Regorafenib is an FDA-approved drug in the third-line therapy of refractory metastatic colorectal cancer. Acquired resistance to cancers and higher toxicity of these drugs are disadvantages to the patients. To counter this, combination therapy is used as a strategy where a minimal dose of drugs can be used to get a higher efficacy and reduce drug resistance development. Ruthenium-based compounds are observed to be a potential alternative to platinum-based drugs due to their significant safety and effectiveness. Formerly, our lab reported Ru-1, a ruthenium-based compound, for its anticancer activity against multiple cancer cells, such as HepG2, HCT116, and MCF7. This study evaluates Ru-1's activity against regorafenib-resistant HCT116 cells and as a combination therapeutic with regorafenib. Meanwhile, the mechanism of the effect of Ru-1 alone and with regorafenib as a combination is still unknown. In this study, we tested a drug combination (Ru-1 and regorafenib) against a panel of HT29, HCT116, and regorafenib-resistant HCT116 cells. The combination showed a synergistic inhibitory activity. Several mechanisms underlying these numerous synergistic activities, such as anti-proliferative efficacy, indicated that the combination exhibited potent cytotoxicity and enhanced apoptosis induction. Disruption of mitochondrial membrane potential increased intracellular ROS levels and decreased migratory cell properties were observed. The combination exhibited its activity by regulating PI3K/Akt and p38 MAP kinase signalling. This indicates that the combination of REG/Ru-1 targets cancer cells by modulating the PI3K/Akt and ERK signalling.

Anticancer application of ferrocene appended configuration-regulated half-sandwich iridium(III) pyridine complexes

Ferrocenyl derivatives and half-sandwich iridium(III) complexes have received extensive attention in the field of anticancer. In this paper, series of configuration-controlled ferrocene-modified half-sandwich iridium(III) pyridine complexes were prepared. The combination of half-sandwich iridium(III) complexes and ferrocenyl unit successfully improved the anticancer activity of these complexes, especially for trans-configurational one towards A549 cells, and the best-performing (FeIr5) was almost 3.5 times more potent than that of cisplatin. In addition, these complexes could inhibit the migration of A549 cells. Complexes can accumulate in intracellular lysosomes (PCC: >0.75), induce lysosomal damage, disturb the cell circle, decrease the mitochondrial membrane potential, improve the intracellular reactive oxygen species (ROS) levels, and eventually lead to apoptosis. Meanwhile, complexes could bind to serum protein following a static quenching mechanism and transport through it. Then, ferrocene-modified half-sandwich iridium(III) pyridine complexes hold the promise as potential organometallic anticancer agents for further investigation.

A review on the chemistry of novel platinum chelates based on azo-azomethine ligands

Numerous platinum group metals (PGMs) complexes contain azo-azomethine-based ligands. Azo-azomethine ligands are N-donor ligands that have extended conjugated π-bonded systems and both azo (–N=N–) and aldimine (–C=N–) functions in their structure. Plenty of platinum (Pt) complexes with azo-imine ligands have been prepared and characterized. Various multidentate azo-imine ligands coordinated with different platinum metal substrates afforded structurally diverse platinum chelates. Nonetheless, many azo-imine-based platinum complexes demonstrated a wide range of biological activities, photo-switchable properties, and redox activities. The review encompasses a general overview of platinum complexes with versatile azo-azomethine ligands, their synthetic protocol, spectroscopic and structural features, chemical reactivity, and multipurpose applications in different areas.

Degradable polyprodrugs: design and therapeutic efficiency

Prodrugs are developed to increase the therapeutic properties of drugs and reduce their side effects. Polyprodrugs emerged as highly efficient prodrugs produced by the polymerization of one or several drug monomers. Polyprodrugs can be gradually degraded to release therapeutic agents. The complete degradation of polyprodrugs is an important factor to guarantee the successful disposal of the drug delivery system from the body. The degradation of polyprodrugs and release rate of the drugs can be controlled by the type of covalent bonds linking the monomer drug units in the polymer structure. Therefore, various types of polyprodrugs have been developed based on polyesters, polyanhydrides, polycarbonates, polyurethanes, polyamides, polyketals, polymetallodrugs, polyphosphazenes, and polyimines. Furthermore, the presence of stimuli-responsive groups, such as redox-responsive linkages (disulfide, boronate ester, metal-complex, and oxalate), pH-responsive linkages (ester, imine, hydrazone, acetal, orthoester, P-O and P-N), light-responsive (metal-complex, o-nitrophenyl groups) and enzyme-responsive linkages (ester, peptides) allow for a selective degradation of the polymer backbone in targeted tumors. We envision that new strategies providing a more efficient synergistic therapy will be developed by combining polyprodrugs with gene delivery segments and targeting moieties.

Rationally designed Ru(II) metallacycles with tunable imidazole ligands for synergistical chemo-phototherapy of cancer

Herein, we construct a series of Ru(II) metallacycles with multimodal chemo-phototherapeutic properties, which exhibited much higher anticancer activity and better cancer-cell selectivity than cisplatin. The antitumor mechanism could be ascribed to the activation of caspase 3/7 and the resulting apoptosis. These results open new possibilities for Ru(II) metallacycles in biomedicine.

Recent development of gold(I) and gold(III) complexes as therapeutic agents for cancer diseases

Metal complexes have demonstrated significant antitumor activities and platinum complexes are well established in the clinical application of cancer chemotherapy. However, the platinum-based treatment of different types of cancers is massively hampered by severe side effects and resistance development. Consequently, the development of novel metal-based drugs with different mechanism of action and pharmaceutical profile attracts modern medicinal chemists to design and synthesize novel metal-based agents. Among non-platinum anticancer drugs, gold complexes have gained considerable attention due to their significant antiproliferative potency and efficacy. In most situations, the gold complexes exhibit anticancer activities by targeting thioredoxin reductase (TrxR) or other thiol-rich proteins and enzymes and trigger cell death via reactive oxygen species (ROS). Interestingly, gold complexes were recently reported to elicit biochemical hallmarks of immunogenic cell death (ICD) as an ICD inducer. In this review, the recent progress of gold(I) and gold(III) complexes is comprehensively summarized, and their activities and mechanism of action are documented.

NIR-II Emissive Ru(II) Metallacycle Assisting Fluorescence Imaging and Cancer Therapy

Despite the success of emissive Ruthenium (Ru) agents in biomedicine, problems such as the visible-light excitation/emission and single chemo- or phototherapy modality still hamper their applications in deep-tissue imaging and efficient cancer therapy. Herein, an second nearinfrared window (NIR-II) emissive Ru(II) metallacycle (Ru1000, λ_em  = 1000 nm) via coordination-driven self-assembly is reported, which holds remarkable deep-tissue imaging capability (≈6 mm) and satisfactory chemo-phototherapeutic performance. In vitro results indicate Ru1000 displays promising cellular uptake, good cancer-cell selectivity, attractive anti-metastasis properties, and remarkable anticancer activity against various cancer cells, including cisplatin-resistant A549 cells (IC₅₀  = 3.4 × 10^-6  m vs 92.8 × 10^-6  m for cisplatin). The antitumor mechanism could be attributed to Ru1000-induced lysosomal membrane damage and mitochondrial-mediated apoptotic cell death. Furthermore, Ru1000 also allows the high-performance in vivo NIR-II fluorescence imaging-guided chemo-phototherapy against A549 tumors. This work may provide a paradigm for the development of long-wavelength emissive metallacycle-based agents for future biomedicine.

Cobalt(III) Complexes for Light-Activated Delivery of Acetylacetonate-BODIPY, Cellular Imaging, and Photodynamic Therapy

Cobalt(III) complexes [Co(TPA)(L¹)](ClO₄)₂ (1), [Co(4-COOH-TPA)(L¹)](ClO₄)₂ (2), [Co(TPA)(L²)]Cl₂ (3), and [Co(4-COOH-TPA)(L²)]Cl₂ (4) having acetylacetonate-linked boron-dipyrromethene ligands (L¹, acac-BODIPY; L², acac-diiodo-BODIPY) were prepared and characterized, and their utility as bioimaging and phototherapeutic agents was evaluated (TPA, tris-(2-pyridylmethyl)amine; 4-COOH-TPA, 2-((bis-(2-pyridylmethyl)amino)methyl)isonicotinic acid). HL¹, HL², and complex 1 were structurally characterized by X-ray crystallography. Complexes 1 and 2 on photoactivation or in a reducing environment (excess GSH, ascorbic acid, and 3-mercaptopropionic acid) released the acac-BODIPY ligand. They exhibited strong absorbance near 501 nm (ε ∼ (5.2-5.8) × 10⁴ M^-1 cm^-1) and emission bands near 513 nm (Φ_F ∼ 0.13, λ_ex = 490 nm) in dimethyl sulfoxide (DMSO). Complexes 3 and 4 with absorption maxima at ∼536 and ∼538 nm (ε ∼ (1.2-1.8) × 10⁴ M^-1 cm^-1), respectively, afforded high singlet oxygen quantum yield (Φ_Δ ∼ 0.79) in DMSO. Complexes 1-4 showed Co(III)-Co(II) redox responses near -0.2 V versus saturated calomel electrode (SCE) in dimethylformamide (DMF)-0.1 M tetrabutylammonium perchlorate (TBAP). The photocleavage of pUC19 DNA by complex 4 revealed the formation of both singlet oxygen and superoxide anion radicals as the reactive oxygen species (ROS). Confocal fluorescence microscopy showed the selective accumulation of complex 1 in the endoplasmic reticulum (ER) in A-549 cells. Complex 4 exhibited a high phototherapeutic index value (PI > 7000) in HeLa cancer cells (IC₅₀ ∼ 0.007 μM in visible light of 400-700 nm, total dose ∼5 J cm^-2). The ancillary ligands in the complexes demonstrated a structure-activity relationship and modulated the Co(III)-Co(II) redox potential, the complex solubility, acac-BODIPY ligand release kinetics, and phototherapeutic efficacy.

Low-Intensity Light-Responsive Anticancer Activity of Platinum(II) Complex Nanocolloids on 2D and 3D In Vitro Cancer Cell Model

This study aimed to evaluate the therapeutic efficacy of low-intensity visible light responsive nanocolloids of a Pt-based drug using a 2D and three-dimensional (3D) in vitro cancer cell model. Biocompatible and biodegradable polymeric nanocolloids, obtained using the ultrasonication method coupled with Layer by Layer technology, were characterized in terms of size (100 ± 20 nm), physical stability, drug loading (78%), and photoactivation through spectroscopy studies. The in vitro biological effects were assessed in terms of efficacy, apoptosis induction, and DNA-Pt adducts formation. Biological experiments were performed both in dark and under visible light irradiation conditions, exploiting the complex photochemical properties. The light-stimuli responsive nanoformulation gave a significant enhancement in drug bioactivity. This allowed us to achieve satisfying results by using nanomolar drug concentration (50 nM), which was ineffective in darkness condition. Furthermore, our nanocolloids were validated in 3D in vitro spheroids using confocal microscopy and cytofluorimetric assay to compare their behavior on culture in 2D monolayers. The obtained results confirmed that these nanocolloids are promising tools for delivering Pt-based drugs.

Antiproliferative activity and DNA binding studies of cyclometalated complexes of platinum(II) containing 2-vinylpyridine

The cytotoxic activity of four cyclometalated platinum(II) complexes [PtMe(vpy)(L)], containing 2-vinylpyridine (vpy) and the phosphine ligands (L) PMe₂Ph (1a), PPh₃ (1b), PMePh₂ (1c), and P(c-Hex)₃ (1d), were evaluated against human breast cancer (MDA-MB-231), human lung cancer (A549), human colon cancer (SW1116), and non-tumor epithelial breast (MCF-10 A) cell lines. The highest activity was found for 1c with IC₅₀ values of 21.10 µM, 23.36 µM, and 12.96 µM, compared to cisplatin, which was 10.12 µM, 47.57 µM, and 19.50 µM against the A549, SW1116, and MDA-MB-231 cell lines, respectively. 1a-d showed a higher selectivity index (SI) than cisplatin. Docking studies confirmed interaction to the DNA minor groove for all complexes. Genotoxicity studies on 1c showed interactions with the genomic content of malignant cells. Compared with cisplatin as a positive control, a slight shift was found in the electrophoresis mobility, which was utilized further to study the direct interaction of 1c with DNA.

Effect of cysteine thiols on the catalytic and anticancer activity of Ru(II) sulfonyl-ethylenediamine complexes

We have synthesized a series of novel substituted sulfonyl ethylenediamine (en) Ru^II arene complexes 1-8 of [(η⁶-arene)Ru(R¹-SO₂-EnBz)X], where the arene is benzene, HO(CH₂)₂O-phenyl or biphenyl (biph), X = Cl or I, and R¹ is phenyl, 4-Me-phenyl, 4-NO₂-phenyl or dansyl. The 'piano-stool' structure of complex 3, [(η⁶-biph)Ru(4-Me-phenyl-SO₂-EnBz)I], was confirmed by X-ray crystallography. The values of their aqua adducts were determined to be high (9.1 to 9.7). Complexes 1-8 have antiproliferative activity against human A2780 ovarian, and A549 lung cancer cells with IC₅₀ values ranging from 4.1 to >50 μM, although, remarkably, complex 7 [(η⁶-biph)Ru(phenyl-SO₂-EnBz)Cl] was inactive towards A2780 cells, but as potent as the clinical drug cisplatin towards A549 cells. All these complexes also showed catalytic activity in transfer hydrogenation (TH) of NAD⁺ to NADH with sodium formate as hydride donor, with TOFs in the range of 2.5-9.7 h^-1. The complexes reacted rapidly with the thiols glutathione (GSH) and N-acetyl-L-cysteine (NAC), forming dinuclear bridged complexes [(η⁶-biph)₂Ru₂(GS)₃]^2- or [(η⁶-biph)₂Ru₂(NAC-H)₃]^2-, with the liberation of the diamine ligand which was detected by LC-MS. In addition, the switching on of fluorescence for complex 8 in aqueous solution confirmed release of the chelated DsEnBz ligand in reactions with these thiols. Reactions with GSH hampered the catalytic TH of NAD⁺ to NADH due to the decomposition of the complexes. Co-administration to cells of complex 2 [(η⁶-biph)Ru(4-Me-phenyl-SO₂-EnBz)Cl] with L-buthionine sulfoximine (L-BSO), an inhibitor of GSH synthesis, partially restored the anticancer activity towards A2780 ovarian cancer cells. Complex 2 caused a concentration-dependent G1 phase cell cycle arrest, and induced a significant level of reactive oxygen species (ROS) in A2780 human ovarian cancer cells. The amount of induced ROS decreased with increase in GSH concentration, perhaps due to the formation of the dinuclear Ru-SG complex.

BODIPY Conjugates as Functional Compounds for Medical Diagnostics and Treatment

Fluorescent dyes absorbing and emitting in the visible and near-IR regions are promising for the development of fluorescent probes for labeling and bio-visualization of body cells. The ability to absorb and emit in the long-wavelength region increases the efficiency of recording the spectral signals of the probes due to the higher permeability of the skin layers. Compared to other fluorescent dyes, BODIPYs are attractive due to their excellent photophysical properties-narrow absorption and emission, intense fluorescence, simple signal modulation for the practical applications. As part of conjugates with biomolecules, BODIPY could act as a biomarker, but as therapeutic agent, which allows solving several problems at once-labeling or bioimaging and treatment based on the suppression of pathogenic microflora and cancer cells, which provides a huge potential for practical application of BODIPY conjugates in medicine. The review is devoted to the discussion of the recent, promising directions of BODIPY application in the field of conjugation with biomolecules. The first direction is associated with the development of BODIPY conjugates with drugs, including compounds of platinum, paclitaxel, chlorambucil, isoxazole, capsaicin, etc. The second direction is devoted to the labeling of vitamins, hormones, lipids, and other biomolecules to control the processes of their transport, localization in target cells, and metabolism. Within the framework of the third direction, the problem of obtaining functional optically active materials by conjugating BODIPY with other colored and fluorescent particles, in particular, phthalocyanines, is being solved.

Metalloproteomics for Biomedical Research: Methodology and Applications

Metals are essential components in life processes and participate in many important biological processes. Dysregulation of metal homeostasis is correlated with many diseases. Metals are also frequently incorporated into diagnosis and therapeutics. Understanding of metal homeostasis under (patho)physiological conditions and the molecular mechanisms of action of metallodrugs in biological systems has positive impacts on human health. As an emerging interdisciplinary area of research, metalloproteomics involves investigating metal-protein interactions in biological systems at a proteome-wide scale, has received growing attention, and has been implemented into metal-related research. In this review, we summarize the recent advances in metalloproteomics methodologies and applications. We also highlight emerging single-cell metalloproteomics, including time-resolved inductively coupled plasma mass spectrometry, mass cytometry, and secondary ion mass spectrometry. Finally, we discuss future perspectives in metalloproteomics, aiming to attract more original research to develop more advanced methodologies, which could be utilized rapidly by biochemists or biologists to expand our knowledge of how metal functions in biology and medicine. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Half-Sandwich Cyclometalated RhIII Complexes Bearing Thiolate Ligands: Biomolecular Interactions and In Vitro and In Vivo Evaluations

A class of cyclometalated RhIII complexes [Cp*Rh(ppy)(SR)] bearing thiolate ligands, Cp* = pentamethylcyclopentadienyl, ppy = 2-phenylpyridinate, and R = pyridyl (Spy, 2), pyrimidyl (SpyN, 3), benzimidazolyl (Sbi, 4), and benzothiazolyl (Sbt, 5), were produced and identified by means of spectroscopic methods. The in vitro cytotoxicity of the RhIII compounds in three different human mortal cancerous cell lines (ovarian, SKOV3; breast, MCF-7; lung, A549) and a normal lung (MRC-5) cell line were evaluated, indicating the selectivity of these cyclometalated RhIII complexes to cancer cells. Complex 5, selected for in vivo experiment, has shown an effective inhibition of tumor growth in SKOV3 xenograft mouse model relative to control (p-values < 0.05 and < 0.01). Importantly, the outcomes of H&E (hematoxylin and eosin) staining and hematological analysis revealed negligible toxicity of 5 compared to cisplatin on a functioning of the main organs of mouse. Molecular docking, UV-vis, and emission spectroscopies (fluorescence, 3D fluorescence, synchronous) techniques were carried out on 1-5 to peruse the mechanism of the anticancer activities of these complexes. The obtained data help to manifest the binding affinity between the rhodium compounds and calf thymus DNA (CT-DNA) through the interaction by DNA minor groove and moderate binding affinity with bovine serum albumin (BSA), particularly with the cavity in the subdomain IIA. It can be concluded that the Rh-thiolate complexes are highly promising leads for the development of novel effective DNA-targeted anticancer drugs.

BODIPY-Tagged Platinum(II) Curcumin Complexes for Endoplasmic Reticulum-Targeted Red Light PDT

[Pt(RB)(Cur)]NO₃ (RBC), [Pt(IRB)(Cur)]NO₃ (IRBC), and [Pt(L)(Cur)]NO₃ (PBC), where HCur is curcumin, L is 1-benzyl-2-(2-pyridyl)benzimidazole, and RB and IRB are red-light-active non-iodo and diiodo-BODIPY tagged to L, respectively, were synthesized and characterized, and their anticancer activities were studied (BODIPY, boron-dipyrromethene). RBC and IRBC displayed BODIPY-centered absorption bands within 615-635 nm along with the respective curcumin bands at 445 and 492 nm in 10% dimethyl sulfoxide (DMSO)-Dulbecco's phosphate-buffered saline (DPBS). Emission bands were observed at 723 and 845 nm for RBC and IRBC, respectively, in 10% DMSO-DPBS. RBC (Φ_Δ, 0.27) and IRBC (Φ_Δ, 0.40) generated singlet oxygen in red light (λ = 642 nm) as evidenced from 1,3-diphenylisobenzofuran (DPBF) titrations. The formation of ¹O₂ from BODIPY and HO^• from the curcumin was evidenced from the mechanistic pUC19 DNA photocleavage studies. The BODIPY complexes showed photocytotoxicity in A549, HeLa, and MDA-MB-231 cells while being less toxic in the dark [IC₅₀: 1.3-6.9 μM, red light; 7.2-12.8 μM, 400-700 nm visible light]. The emissive RBC displayed localization in the endoplasmic reticulum (ER). Apoptotic cell death was evidenced from the Annexin-V/fluorescein isothiocyanate (FITC)/propidium iodide (PI) assay and green fluorescence in red light in the Fluo-4 AM assay due to ER stress, and mitochondrial dysfunction was evidenced from the 5,5,6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) assay in A549 cells.

Rationally designed Ru(ii)-metallacycle chemo-phototheranostic that emits beyond 1000 nm

Ruthenium complexes are emerging as potential complements to platinum drugs. They also show promise as photo-diagnostic and therapeutic agents. However, most ruthenium species studied to date as potential drugs are characterized by short excitation/emission wavelengths. This limits their applicability for deep-tissue fluorescence imaging and light-based therapeutic treatments. Here, we report a Ru(ii) metallacycle (Ru1100) that emits at ≥1000 nm. This system possesses excellent deep-tissue penetration capability (∼7 mm) and displays good chemo-phototherapeutic performance. In vitro studies revealed that Ru1100 benefits from good cellular uptake and produces a strong anticancer response against several cancer cell lines, including a cisplatin-resistant A549 cell line (IC₅₀ = 1.6 μM vs. 51.4 μM for cisplatin). On the basis of in vitro studies, it is concluded that Ru1100 exerts its anticancer action by regulating cell cycle progression and triggering cancer cell apoptosis. In vivo studies involving the use of a nanoparticle formulation served to confirm that Ru1100 allows for high-performance NIR-II fluorescence imaging-guided precise chemo-phototherapy in the case of A549 tumour mouse xenografts with no obvious side effects. This work thus provides a paradigm for the development of long-wavelength emissive supramolecular theranostic agents based on ruthenium.

Along-wavelength emissive Ru(ii) metallacycle chemo-phototheranostic was prepared via self-assembly that exhibits excellent photostability, deep-tissue penetration capability, and promising chemo-phototherapeutic performance in vitro and in vivo.

Development of a series of flurbiprofen and zaltoprofen platinum(IV) complexes with anti-metastasis competence targeting COX-2, PD-L1 and DNA

To develop new anti-metastasis chemotherapeutic drugs, a series of flurbiprofen (FLP) and zaltoprofen (ZTP) platinum(IV) complexes targeting COX-2, PD-L1 and DNA were prepared and investigated. Complex 2 with dual FLP...

Iridium tetrazolato complexes as efficient protein staining agents

Iridium tetrazolato complexes have been illustrated as one kind of efficient protein staining agent.

Platinum Complexes as Inhibitors of DNA Repair Protein Ku70 and Topoisomerase IIα in Cancer Cells

Ku70 protein and topoisomerase IIα (Topo IIα) are promising targets of anticancer drugs, which play critical roles in DNA repair and replication processes. Three platinum(II) complexes, [PtCl(NH3)2(9-(pyridin-2-ylmethyl)-9H-carbazole)]NO3 (OPPC), [PtCl(NH3)2(9-(pyridin-3-ylmethyl)-9H-carbazole)]NO3 (MPPC),...

Cisplatin-cyclooxygenase inhibitor conjugates, free and immobilised in mesoporous silica SBA-15, prove highly potent against triple-negative MDA-MB-468 breast cancer cell line

For the development of anticancer drugs with higher activity and reduced toxicity, two approaches were combined: preparation of platinum(IV) complexes exhibiting higher stability compared to their platinum(II) counterparts and loading them into mesoporous silica SBA-15 with the aim to utilise the passive enhanced permeability and retention (EPR) effect of nanoparticles for accumulation in tumour tissues. Three conjugates based on a cisplatin scaffold bearing the anti-inflammatory drugs naproxen, ibuprofen or flurbiprofen in the axial positions (1, 2 and 3, respectively) were synthesised and loaded into SBA-15 to afford the mesoporous silica nanoparticles (MSNs) SBA-15|1, SBA-15|2 and SBA-15|3. Superior antiproliferative activity of both free and immobilised conjugates in a panel of four breast cancer cell lines (MDA-MB-468, HCC1937, MCF-7 and BT-474) with markedly increased cytotoxicity with respect to cisplatin was demonstrated. All compounds exhibit highest activity against the triple-negative cell line MDA-MB-468, with conjugate 1 being the most potent. However, against MCF-7 and BT-474 cell lines, the most notable improvement was found, with IC₅₀ values up to 240-fold lower than cisplatin. Flow cytometry assays clearly show that all compounds induce apoptotic cell death elevating the levels of both early and late apoptotic cells. Furthermore, autophagy as well as formation of reactive oxygen species (ROS) and nitric oxide (NO) were elevated to a similar or greater extent than with cisplatin.

Intrinsically radiopaque biomaterial assortments: a short review on the physical principles, X-ray imageability, and state-of-the-art developments

X-ray attenuation ability, otherwise known as radiopacity of a material, could be indisputably tagged as the central and decisive parameter that produces contrast in an X-ray image. Radiopaque biomaterials are vital in the healthcare sector that helps clinicians to track them unambiguously during pre and post interventional radiological procedures. Medical imaging is one of the most powerful resources in the diagnostic sector that aids improved treatment outcomes for patients. Intrinsically radiopaque biomaterials enable themselves for visual targeting/positioning as well as to monitor their fate and further provide the radiologists with critical insights about the surgical site. Moreover, the emergence of advanced real-time imaging modalities is a boon to the contemporary healthcare systems that allow to perform minimally invasive surgical procedures and thereby reduce the healthcare costs and minimize patient trauma. X-ray based imaging is one such technologically upgraded diagnostic tool with many variants like digital X-ray, computed tomography, digital subtraction angiography, and fluoroscopy. In light of these facts, this review is aimed to briefly consolidate the physical principles of X-ray attenuation by a radiopaque material, measurement of radiopacity, classification of radiopaque biomaterials, and their recent advanced applications.

Albumin-encapsulated Nanoparticles of Naproxen Platinum(IV) Complexes with Inflammation Inhibitory Competence Displaying Effective Antitumor Activities in vitro and in vivo

BACKGROUND

Platinum(IV) complexes with inflammation inhibitory properties are much favored in improving antitumor activities. Nanodrug-delivery system as a preferable measure for antitumor therapy are widely explored in platinum(IV) drug delivery.

PURPOSE

The aim for this study was to develop novel bovine serum albumin (BSA) nanoparticles (NPs) based on naproxen platinum(IV) complexes to display a synergistic antitumor mechanism targeting cyclooxygenase-2 (COX-2), metalloproteinase-9 (MMP-9) and inducible nitric oxide synthase (iNOS).

METHODS

Herein, we reported the preparation of two BSA NPs of naproxen platinum(IV) complexes, and their antitumor activities were investigated in vitro and in vivo.

RESULTS

Both NPs possessed relatively uniform size and good stability for 30 days in aqueous solution. They exhibited prominent antitumor activities in vitro, and showed great potential in reversing drug resistance. Furthermore, these two NPs played superior tumor growth suppression in vivo in contrast to the free compounds, which were comparable to that of cisplatin and oxaliplatin, but induced lower toxic influences than platinum(II) drugs especially to spleen and liver. Moreover, the naproxen platinum(IV) NPs could decrease tumor inflammation targeting COX-2, MMP-9 and iNOs, and decreasing NO production, which would be in favor of enhancing the antitumor competence, and reducing toxicity.

CONCLUSION

Taken together, BSA NPs of naproxen platinum(IV) complexes demonstrated a powerful antitumor efficacy in vitro and in vivo. The platinum(IV) NPs with inflammation inhibitory competence targeting multiple enzymes reported in this work afford a new strategy for the development of antitumor therapy to overcome drawbacks of clinical platinum(II) drugs.

Investigation on Optical and Biological Properties of 2-(4-Dimethylaminophenyl)benzothiazole Based Cycloplatinated Complexes

The optical and biological properties of 2-(4-dimethylaminophenyl)benzothiazole cycloplatinated complexes featuring bioactive ligands ([{Pt(Me 2 N-pbt)(C 6 F 5 )}L] [L = Me 2 N-pbtH 1 , p -dpbH (4-(diphenylphosphino)benzoic acid) 2 , o -dpbH (2-(diphenylphosphino)benzoic acid) 3) , [Pt(Me 2 N-pbt)( o -dpb)] 4 ,  [{Pt(Me 2 N-pbt)(C 6 F 5 )} 2 (µ-PR n P)] [PR 4 P = O(CH 2 CH 2 OC(O)C 6 H 4 PPh 2 ) 2 5 , PR 12 P = O{(CH 2 CH 2 O) 3 C(O)C 6 H 4 PPh 2 } 2 6 ] are presented. Complexes 1-6 display 1 ILCT and metal perturbed 3 ILCT dual emissions. The ratio between both bands is excitation dependent, accomplishing warm-white emissions for 2 , 5 and 6 .  The phosphorescent emission is lost in aerated solutions owing to photoinduced electron transfer to 3 O 2 and formation of 1 O 2 , as confirmed in complexes 2 and 4 . They also exhibit photoinduced phosphorescence enhancement in non-degassed DMSO, due to local oxidation of DMSO by sensitized 1 O 2 , which causes a local degassing. Me 2 N-pbtH and the complexes exhibit specific accumulation in the Golgi apparatus although only 2 , 3 and 6 were active against A549 and HeLa cancer cell lines, being 6 highly selective respect to nontumoral cells. The potential photodynamic property of these complexes was demonstrated with complex 4 .

Supramolecular Polymerization-Induced Nanoassemblies for Self-Augmented Cascade Chemotherapy and Chemodynamic Therapy of Tumor

The clinical application of chemodynamic therapy is impeded by the insufficient intracellular H2 O2 level in tumor tissues. Herein, we developed a supramolecular nanoparticle via a simple one-step supramolecular polymerization-induced self-assembly process using platinum (IV) complex-modified β-cyclodextrin-ferrocene conjugates as supramolecular monomers. The supramolecular nanoparticles could dissociate rapidly upon exposure to endogenous H2 O2 in the tumor and release hydroxyl radicals as well as platinum (IV) prodrugs in situ, which is reduced into cisplatin to significantly promote the generation of H2 O2 in the tumor tissue. Thus, the supramolecular nanomedicine overcomes the limitation of conventional chemodynamic therapy via the self-augmented cascade radical generation and drug release. In addition, dissociated supramolecular nanoparticles could be readily excreted from the body via renal clearance to effectively avoid systemic toxicity and ensure long term biocompatibility of the nanomedicine. This work may provide new insights on the design and development of novel supramolecular nanoassemblies for cascade chemo/chemodynamic therapy.