Dual-sensitive dual-prodrug nanoparticles with light-controlled endo/lysosomal escape for synergistic photoactivated chemotherapy

Self-Assembled Metal Complexes in Biomedical Research

Cisplatin is widely used in clinical cancer treatment; however, its application is often hindered by severe side effects, particularly inherent or acquired resistance of target cells. To address these challenges, an effective strategy is to modify the metal core of the complex and introduce alternative coordination modes or valence states, leading to the development of a series of metal complexes, such as platinum (IV) prodrugs and cyclometalated complexes. Recent advances in nanotechnology have facilitated the development of multifunctional nanomaterials that can selectively deliver drugs to tumor cells, thereby overcoming the pharmacological limitations of metal-based drugs. This review first explores the self-assembly of metal complexes into spherical, linear, and irregular nanoparticles in the context of biomedical applications. The mechanisms underlying the self-assembly of metal complexes into nanoparticles are subsequently analyzed, followed by a discussion of their applications in biomedical fields, including detection, imaging, and antitumor research.

Oral bomb effect nanotherapeutics alleviate ulcerative colitis through coordinated anti-inflammatory and pro-resolving strategies

Background: Ulcerative colitis (UC) is a debilitating chronic inflammatory bowel disease, and current treatments primarily focus on suppressing inflammation with limited efficacy. However, the resolution of inflammation also plays a crucial role in UC prognosis. Combining anti-inflammatory and pro-inflammatory resolution interventions may be a promising approach for treating UC. Materials and methods: The nano-bomb nanoparticles were validated for their ability to load CD98 siRNA (siCD98) and Annexin A1-mimetic peptides (Ac2-26 peptides), as well as release CO2 upon lysosomal escape. Surface modification with hyaluronic acid (HA) was assessed for its capability to target inflammatory tissues and cells. Biocompatibility and biosafety were evaluated through in vitro and in vivo studies. The anti-inflammatory and pro-resolving effects of siCD98@NPs and Ac2-26@NPs, both individually and in combination, were evaluated by measuring ROS production, pro-inflammatory cytokine expression, CD98 gene expression, and macrophage polarization. Results: These nanoparticles could efficiently load siCD98 and Ac2-26 peptides and release CO2 under acidic pH in the endo/lysosome to deliver drugs to the cytoplasm. HA could effectively target the inflammatory tissue and cells, showing good biocompatibility and biosafety both in vitro and in vivo. siCD98@NPs and Ac2-26@NPs showed anti-inflammatory effects by eliminating the over-production of ROS and down-regulating the expression of pro-inflammatory cytokines (TNF-α and IL-1β) and the CD98 gene; meanwhile, it showed pro-resolving function by inhibiting M0 to pro-inflammatory M1 macrophage conversion, with a more pronounced effect when combined with siCD98 and Ac2-26. The oral administration of chitosan-alginate hydrogel-encapsulated nanoparticles in UC model mice effectively alleviated inflammatory symptoms, reduced the expression of pro-inflammatory cytokines (TNF-α and IL-1β) and the CD98 gene, restored intestinal barrier function, and promoted M1 to M2 polarization, with a more pronounced effect when combined. Conclusion: By combining anti-inflammatory and pro-resolution interventions, these nanoparticles offer a novel therapeutic approach. This study offered a new approach for combination therapy of UC.

Hydroxyethyl starch conjugates co-assembled nanoparticles promote photodynamic therapy and antitumor immunity by inhibiting antioxidant systems

Photodynamic therapy (PDT) can produce high levels of reactive oxygen species (ROS) to kill tumor cells and induce antitumor immunity. However, intracellular antioxidant systems, including glutathione (GSH) system and thioredoxin (Trx) system, limit the accumulation of ROS, resulting in compromised PDT and insufficient immune stimulation. Herein, we designed a nanomedicine PtHPs co-loading photosensitizer pyropheophorbide a (PPa) and cisplatin prodrug Pt-COOH(IV) (Pt (IV)) based on hydroxyethyl starch (HES) to inhibit both GSH and Trx antioxidant systems and achieve potent PDT as well as antitumor immune responses. Specifically, HES-PPa and HES-Pt were obtained by coupling HES with PPa and Pt (IV), and assembled into nanoparticle PtHPs by emulsification method to achieve the purpose of co-delivery of PPa and Pt (IV). PtHPs improved PPa photostability while retaining PPa photodynamic properties. In vitro experiments showed that PtHPs reduced GSH, inhibited Trx system and had better cell-killing effect and ROS generation ability. Subcutaneous tumor models showed that PtHPs had good safety and tumor inhibition effect. Bilateral tumor models suggested that PtHPs promoted the release of damage-associated molecular patterns and the maturation of dendritic cells, induced T cell-mediated immune responses, and thus suppressed the growth of both primary and distal tumors. This study reports a novel platinum-based nanomedicine and provides a new strategy for boosting PDT therapy-mediated antitumor immunity by overcoming intrinsic antioxidant systems.

Enteral Route Nanomedicine for Cancer Therapy

With the in-depth knowledge of the pathological and physiological characteristics of the intestinal barrier-portal vein/intestinal lymphatic vessels-systemic circulation axis, oral targeted drug delivery is frequently being renewed. With many advantages, such as high safety, convenient administration, and good patient compliance, many researchers have begun to explore targeted drug delivery from intravenous injections to oral administration. Over the past few decades, the fields of materials science and nanomedicine have produced various drug delivery platforms that hold great potential in overcoming the multiple barriers associated with oral drug delivery. However, the oral transport of particles into the systemic circulation is extremely difficult due to immune rejection and biochemical invasion in the intestine, which limits absorption and entry into the bloodstream. The feasibility of the oral delivery of targeted drugs to sites outside the gastrointestinal tract (GIT) is unknown. This article reviews the biological barriers to drug absorption, the in vivo fate and transport mechanisms of drug carriers, the theoretical basis for oral administration, and the impact of carrier structural evolution on oral administration to achieve this goal. Finally, this article reviews the characteristics of different nano-delivery systems that can enhance the bioavailability of oral therapeutics and highlights their applications in the efficient creation of oral anticancer nanomedicines.

A photoactivatable upconverting nanodevice boosts the lysosomal escape of PROTAC degraders for enhanced combination therapy

PROteolysis TArgeting Chimeras have received increasing attention due to their capability to induce potent degradation of various disease-related proteins. However, the effective and controlled cytosolic delivery of current small-molecule PROTACs remains a challenge, primarily due to their intrinsic shortcomings, including unfavorable solubility, poor cell permeability, and limited spatiotemporal precision. Here, we develop a near-infrared light-controlled PROTAC delivery device (abbreviated as USDPR) that allows the efficient photoactivation of PROTAC function to achieve enhanced protein degradation. The nanodevice is constructed by encapsulating the commercial BRD4-targeting PROTACs (dBET6) in the hollow cavity of mesoporous silica-coated upconversion nanoparticles, followed by coating a Rose Bengal (RB) photosensitizer conjugated poly-L-lysine (PLL-RB). This composition enables NIR light-activatable generation of cytotoxic reactive oxygen species due to the energy transfer from the UCNPs to PLL-RB, which boosts the endo/lysosomal escape and subsequent cytosolic release of dBET6. We demonstrate that USDPR is capable of effectively degrading BRD4 in a NIR light-controlled manner. This in combination with NIR light-triggered photodynamic therapy enables an enhanced antitumor effect both in vitro and in vivo. This work thus presents a versatile strategy for controlled release of PROTACs and codelivery with photosensitizers using an NIR-responsive nanodevice, providing important insight into the design of effective PROTAC-based combination therapy.

Photoactivated full-API nanodrug (FAND): harnessing transition metal complexes and MTH1 inhibitor for enhanced DNA damage in cancer cells

The effectiveness of photodynamic therapy (PDT) has been greatly restricted by the hypoxic tumor microenvironment and the susceptible resistance of monotherapy. Although nanodrugs based on transition metal complexes capable of integrating PDT with photoactivated chemotherapy (PACT) have garnered tremendous attention as promising candidates for overcoming the above limitations, the therapeutic efficacy of these nanodrugs is still hampered by inadequate loading of active pharmaceutical ingredients (APIs) and the inherent ability of cancer cells to repair damaged DNA. Herein, we developed a photoactivated full-API nanodrug, Ru-T FAND, by one-step self-assembly of RuDPB and TH287. By virtue of its 100 wt% API content and favorable stability in water, the Ru-T FAND exhibited improved cellular uptake behavior and intracellular 1O2 generation. Attractively, the Ru-T FAND with triple anti-cancer modalities can photogenerate 1O2, photo-release DPB ligand and inhibit the repair of DNA damage, ultimately enhancing its phototherapeutic effect on cancer cells. Importantly, the uncaged DPB ligand from RuDPB emits red fluorescence, enabling real-time monitoring of the drug's absorption, distribution and efficacy. Collectively, the presented photoactivated Ru-T FANDs with multiple anti-cancer mechanisms will expand new horizons for the development of safe, efficient and synergistic tumor phototherapy strategies.

Recent Advances of Platinum-Based Anticancer Complexes in Combinational Multimodal Therapy

Platinum drugs with manifest therapeutic effects are widely used, but their systemic toxicity and the drug resistance acquired by cancer cells limit their clinical applications. Thus, the exploration on appropriate methods and strategies to overcome the limitations of traditional platinum drugs becomes extremely necessary. Combination therapy of platinum drugs can inhibit tumor growth and metastasis in an additive or synergistic manner, and can potentially reduce the systemic toxicity of platinum drugs and overcome platinum-resistance. This review summarizes the various modalities and current progress in platinum-based combination therapy. The synthetic strategies and therapeutic effects of some platinum-based anticancer complexes in the combination of platinum drugs with gene editing, ROS-based therapy, thermal therapy, immunotherapy, biological modelling, photoactivation, supramolecular self-assembly and imaging modality are briefly described. Their potential challenges and prospects are also discussed. It is hoped that this review will inspire researchers to have more ideas for the future development of highly effective platinum-based anti-cancer complexes.

Visible light-activatable platinum(IV) prodrugs harnessing CD36 for ovarian cancer therapy

We hereby engineered photoactivatable Pt(IV) metallodrugs that harness CD36 to target ovarian cancer cells. Pt(IV) compounds mimic the structure of fatty acids and take advantage of CD36 as a "Trojan horse" to gain entry into the cells. We confirmed that CD36-dependent entry occurs using graphite furnace atomic absorption spectroscopy with ovarian cancer cells expressing different levels of CD36 and a CD36 inhibitor, SSO. Once the Pt(IV) metallodrugs enter the cancer cells, they can be activated to form Pt(II) with characteristics of cisplatin under visible light (490 nm) irradiation, promoting photoinduced electron transfer from the attached fluorophore to the metal center. This light-induced activation can increase the cytotoxicity of the Pt(IV) metallodrugs by up to 20 times toward ovarian cancer cells, inducing DNA damage and enabling efficient elimination of drug-resistant cancer cells.

Older but Stronger: Development of Platinum-Based Antitumor Agents and Research Advances in Tumor Immunity

Platinum (Pt) drugs have developed rapidly in clinical applications because of their broad and highly effective antitumor effects. In recent years, with the rapid development of immunotherapy, Pt-based antitumor agents have gained new challenges and opportunities. Since the discovery of their pharmacological effects in immunotherapy and tumor microenvironment regulation, research into Pt drugs has progressed to multi-ligand and multi-functional Pt precursors and their own shortcomings have been further highlighted. With the development of antitumor immunotherapy and the rise of combination therapy, the development of Pt-based drugs has started to move in the direction of multi-targeting, nanocarrier modification, immunotherapy and photodynamic therapy. In this paper, we first overview the recent applications of Pt-based drugs in antitumor inorganic chemistry, with a focus on summarizing the application of Pt-based drugs and their precursors in the anticancer immune response. The paper also provides a reasonable outlook on the future development of Pt-based drugs from the chemical and immunological perspectives, relying on the existing content and problems of Pt-based drug development. On the basis of the gathered information, joint multidisciplinary programs on implementing comprehensive immune analyses for the future development of novel anticancer metal compounds should be initiated.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

Copper-Nitrogen-Coordinated Carbon Dots: Transformable Phototheranostics from Precise PTT/PDT to Post-Treatment Imaging-Guided PDT for Residual Tumor Cells

Phototheranostics has attracted considerable attention in the fields of cancer diagnosis and treatment. However, the complete eradication of solid tumors using traditional phototheranostics is difficult because of the limited depth and range of laser irradiation. New phototheranostics enabling precise phototherapy and post-treatment imaging-guided programmed therapy for residual tumors is urgently required. Accordingly, this study developed a novel transformable phototheranostics by assembling hyaluronic acid (HA) with copper-nitrogen-coordinated carbon dots (CDs). In this transformable nanoplatform, named copper-nitrogen-CDs@HA, the HA component enables the specific targeting of cluster determinant (CD) 44-overexpressing tumor cells. In the tumor cells, redox glutathione converts Cu(II) (cupric ions) into Cu(I) (cuprous ions), which confers the novel transformable functionality to phototheranostics. Both in vitro and in vivo results reveal that the near-infrared-light-photoactivated Cu^II-N-CDs@HA could target CD44-overexpressing tumor cells for precise synergistic photothermal therapy and photodynamic therapy. This study is the first to observe that Cu^II-N-CDs@HA could escape from lysosomes and be transformed in situ into Cu^I-N-CDs@HA in tumor cells, with the d⁹ electronic configuration of Cu(II) changing to the d¹⁰ electronic configuration of Cu(I), which turns on their fluorescence and turns off their photothermal properties. This transformable phototheranostics could be used for post-treatment imaging-guided photodynamic therapy on residual tumor cells. Thus, the rationally designed copper-nitrogen-coordinated CDs offer a simple in situ transformation strategy for using multiple-stimulus-responsive precise phototheranostics in post-treatment monitoring of residual tumor cells and imaging-guided programmed therapy.

Ruthenium-based antitumor drugs and delivery systems from monotherapy to combination therapy

Ruthenium complex is an important compound group for antitumor drug research and development. NAMI-A, KP1019, TLD1433 and other ruthenium complexes have entered clinical research. In recent years, the research on ruthenium antitumor drugs has not been limited to single chemotherapy drugs; other applications of ruthenium complexes have emerged such as in combination therapy. During the development of ruthenium complexes, drug delivery forms of ruthenium antitumor drugs have also evolved from single-molecule drugs to nanodrug delivery systems. The review summarizes the following aspects: (1) ruthenium complexes from monotherapy to combination therapy, including the development of single-molecule compounds, carrier nanomedicine, and self-assembly of carrier-free nanomedicine; (2) ruthenium complexes in the process of ADME in terms of absorption, distribution, metabolism and excretion; (3) the applications of ruthenium complexes in combination therapy, including photodynamic therapy (PDT), photothermal therapy (PTT), photoactivated chemotherapy (PACT), immunotherapy, and their combined application; (4) the future prospects of ruthenium-based antitumor drugs.

The role of Platinum(IV)-based antitumor drugs and the anticancer immune response in medicinal inorganic chemistry. A systematic review from 2017 to 2022

Platinum-based antitumor drugs have been used in many types of tumors due to its broad antitumor spectrum in clinic. Encouraged by the cisplatin's (CDDP) worldwide success in cancer chemotherapy, the research in platinum-based antitumor drugs has evolved from traditional platinum drug to multi-ligand and multifunctional platinum prodrugs over half a century. With the rapid development of metal drugs and the anticancer immune response, challenges and opportunities in platinum drug research have been shifted from traditional platinum-based drugs to platinum-based hybrids and the direction of development is tending toward photodynamic therapy, nano-delivery therapy, drug combination, targeted therapy, diagnostic therapy, immune-combination therapy and tumor stem cell therapy. In this review, we first exhaustively overviewed the role of platinum-based antitumor prodrugs and the anticancer immune response in medicinal inorganic chemistry based on the special nanomaterials, the modification of specific ligands, and the multiple functions obtained that are beneficial for tumor therapy in the last five years. We also categorized them according to drug potency and function. There hasn't been a comprehensive evaluation of precursor platinum drugs in prior articles. And a multifarious approach to distinguish and detail the variety of alterations of platinum-based precursors in various valence states also hasn't been summarized. In addition, this review points out the main problems at the interface of chemistry, biology, and medicine from their action mechanisms for current platinum drug development, and provides up-to-date potential strategies from drug design perspectives to circumvent those drawbacks. And a promising idea is also enlightened for researchers in the development and discovery of platinum prodrugs.