Mitochondria-targeting multifunctional nanoplatform for cascade phototherapy and hypoxia-activated chemotherapy

Adaptive Synthesis, Supramolecular Behavior, and Biological Properties of Amphiphilic Carbosilane-Phosphonium Dendrons with Tunable Structure

Here, we present a modular synthesis as well as physicochemical and biological evaluation of a new series of amphiphilic dendrons carrying triphenylphosphonium groups at their periphery. Within the series, the size and mutual balance of lipophilic and hydrophilic domains are systematically varied, changing the dendron shape from cylindrical to conical. In physiological solution, the dendrons exhibit very low critical micelle concentrations (2.6-4.9 μM) and form stable and uniform micelles 6-12 nm in diameter, depending on dendron shape; the results correlate well with molecular dynamics simulations. The compounds show relatively high cytotoxicity (IC50 1.2-21.0 μM) associated with micelle formation and inversely related to the size of assembled particles. Depending on their shape, the dendrons show promising results in terms of dendriplex formation and antibacterial activity. In addition to simple amphiphilic dendrons, a fluorescently labeled analogue was also prepared and utilized as an additive visualizing the dendron's cellular uptake.

Recent progress of porphyrin metal-organic frameworks for combined photodynamic therapy and hypoxia-activated chemotherapy

Nanoscale metal-organic frameworks integrated with porphyrins (Por-nMOFs) have emerged as efficient nanoplatforms for photodynamic therapy (PDT), which relies on the conversion of molecular oxygen into cytotoxic singlet oxygen. However, the hypoxic microenvironment within tumors significantly limits the efficacy of PDT. To address this challenge, researchers have explored various strategies to either alter or exploit the hypoxic conditions in tumors. One such strategy involves leveraging the porous structure of Por-nMOFs to load hypoxia-activated prodrugs (HAPs) like tirapazamine (TPZ), thereby utilizing the tumor's intrinsic hypoxic environment to trigger a chemotherapeutic effect that synergizes with PDT. Advances in nanoscience have enabled the development of porphyrin-based nMOFs capable of simultaneously loading both porphyrin photosensitizers and TPZ, ensuring effective release within cancer cells under high-phosphate conditions. The subsequent activation of co-loaded TPZ, by the tumor's own hypoxic microenvironment, and that created during PDT, facilitates a combined PDT and chemotherapy approach. This method not only enhances the suppression of cancer cell proliferation but also improves control over tumor metastasis while mitigating the negative impact of hypoxia on singular Por-nMOFs in PDT. This review summarizes recent advances in Por-nMOFs research, focusing on the design strategies for enhancing water dispersibility, circulatory stability, and targeting specificity through post-synthetic modifications. Additionally, this review highlights the bioapplication of Por-nMOFs by integrating TPZ chemotherapy and other therapeutic modalities to combat hypoxic and metastatic malignancies. We anticipate that this review will inspire further research into Por-nMOFs and advance their application in biomedicine.

Determinants of Photodynamic Therapy Resistance in Cancer Cells

Photodynamic therapy (PDT) has emerged as a promising therapeutic approach owing to its non-invasive nature and minimal toxicity. PDT involves the administration of a photosensitizing agent (PS), which, upon light activation, induces a photodynamic reaction (PDR), leading to targeted cell destruction. However, developing resistance to PDT poses a significant challenge to its effectiveness. Various factors, including properties and administration of PSs, mediate this resistance. Despite the widespread use of substances like 5-aminolevulinic acid (5-ALA) and protoporphyrin, their efficacy is limited due to restricted tumor penetration and a lack of tumor targeting. To address these limitations, nano-delivery techniques and newer PSs like Aza-BODIPY and its derivatives, which offer enhanced tissue penetration, are being explored. In this paper, we provide an overview of resistance mechanisms in PDT and discuss novel methods, substances, and technologies to overcome resistance to improve clinical outcomes in tumor treatment.

Remote Manipulation of TRPV1 Signaling by Near-Infrared Light-Triggered Nitric Oxide Nanogenerators for Specific Cancer Therapy

Specific activation of transient receptor potential vanilloid member 1 (TRPV1) channels provides a new avenue for cancer treatment by inducing excessive Ca2+ influx. However, controllable manipulation of TRPV1 signaling for clinical application has remained elusive due to the challenge in finding a mild and effective method of exerting external stimulus without adverse side effects in living systems. Herein, a TRPV1-targeting near-infrared (NIR) triggered nitric oxide (NO)-releasing nanoplatform (HCuS@PDA-TRPV1/BNN6) based on polydopamine (PDA) coated hollow copper sulfide nanoparticles (HCuS NPs) is developed for specific cancer therapy. Upon NIR irradiation, the NO donor BNN6 encapsulated in NIR-responsive nanovehicles can locally generate NO to activate TRPV1 channels and induce Ca2+ influx. This NIR controlled mode enables the nanoplatform to exert its therapeutic effects below the apoptotic threshold temperature (43°C), minimizing the photothermal damage to normal tissue. Integrating this special NO-mediated therapy with HCuS NPs mediated chemodynamic therapy, the designed nanoplatform exhibits a boosted anticancer activity with negligible systematic toxicity. Together, this study provides a promising strategy for site-specific cancer therapy by spatiotemporally controlled activation of surface ion channels, thus offering a solution to an unmet clinical need in cancer treatment.

Mitochondria-Targeting and Oxygen Self-Supplying Eccentric Hollow Nanoplatform for Enhanced Breast Cancer Photodynamic Therapy

Photodynamic therapy (PDT) has received increasing attention for tumor therapy due to its minimal invasiveness and spatiotemporal selectivity. However, the poor targeting of photosensitizer and hypoxia of the tumor microenvironment limit the PDT efficacy. Herein, eccentric hollow mesoporous organic silica nanoparticles (EHMONs) are prepared by anisotropic encapsulation and hydrothermal etching for constructing PDT nanoplatforms with targeting and hypoxia-alleviating properties. The prepared EHMONs possess a unique eccentric hollow structure, a uniform size (300 nm), a large cavity, and ordered mesoporous channels (2.3 nm). The EHMONs are modified with the mitochondria-targeting molecule triphenylphosphine (CTPP) and photosensitizers chlorin e6 (Ce6). Oxygen-carrying compound perfluorocarbons (PFCs) are further loaded in the internal cavity of EHMONs. Hemolytic assays and in vitro toxicity experiments show that the EHMONs-Ce6-CTPP possesses very good biocompatibility and can target mitochondria of triple-negative breast cancer, thus increasing the accumulation of photosensitizers Ce6 at mitochondria after entering cancer cells. The EHMONs-Ce6-CTPP@PFCs with oxygen-carrying ability can alleviate hypoxia after entering in the cancer cell. Phantom and cellular experiments show that the EHMONs-Ce6-CTPP@PFCs produce more singlet oxygen reactive oxygen species (ROSs). Thus, in vitro and in vivo experiments demonstrated that the EHMONs-Ce6-CTPP@PFCs showed excellent treatment effects for triple-negative breast cancer. This research provides a new method for a targeting and oxygen-carrying nanoplatform for enhancing PDF effectiveness.

TME-Related Biomimetic Strategies Against Cancer

The tumor microenvironment (TME) plays an important role in various stages of tumor generation, metastasis, and evasion of immune monitoring and treatment. TME targeted therapy is based on TME components, related pathways or active molecules as therapeutic targets. Therefore, TME targeted therapy based on environmental differences between TME and normal cells has been widely studied. Biomimetic nanocarriers with low clearance, low immunogenicity, and high targeting have enormous potential in tumor treatment. This review introduces the composition and characteristics of TME, including cancer‑associated fibroblasts (CAFs), extracellular matrix (ECM), tumor blood vessels, non-tumor cells, and the latest research progress of biomimetic nanoparticles (NPs) based on TME. It also discusses the opportunities and challenges of clinical transformation of biomimetic nanoparticles.

Cuproptosis: A novel therapeutic target for overcoming cancer drug resistance

Cuproptosis is a newly identified form of cell death driven by copper. Recently, the role of copper and copper triggered cell death in the pathogenesis of cancers have attracted attentions. Cuproptosis has garnered enormous interest in cancer research communities because of its great potential for cancer therapy. Copper-based treatment exerts an inhibiting role in tumor growth and may open the door for the treatment of chemotherapy-insensitive tumors. In this review, we provide a critical analysis on copper homeostasis and the role of copper dysregulation in the development and progression of cancers. Then the core molecular mechanisms of cuproptosis and its role in cancer is discussed, followed by summarizing the current understanding of copper-based agents (copper chelators, copper ionophores, and copper complexes-based dynamic therapy) for cancer treatment. Additionally, we summarize the emerging data on copper complexes-based agents and copper ionophores to subdue tumor chemotherapy resistance in different types of cancers. We also review the small-molecule compounds and nanoparticles (NPs) that may kill cancer cells by inducing cuproptosis, which will shed new light on the development of anticancer drugs through inducing cuproptosis in the future. Finally, the important concepts and pressing questions of cuproptosis in future research that should be focused on were discussed. This review article suggests that targeting cuproptosis could be a novel antitumor therapy and treatment strategy to overcome cancer drug resistance.

Photothermal therapy of copper incorporated nanomaterials for biomedicine

Studies have reported on the significance of copper incorporated nanomaterials (CINMs) in cancer theranostics and tissue regeneration. Given their unique physicochemical properties and tunable nanostructures, CINMs are used in photothermal therapy (PTT) and photothermal-derived combination therapies. They have the potential to overcome the challenges of unsatisfactory efficacy of conventional therapies in an efficient and non-invasive manner. This review summarizes the recent advances in CINMs-based PTT in biomedicine. First, the classification and structure of CINMs are introduced. CINMs-based PTT combination therapy in tumors and PTT guided by multiple imaging modalities are then reviewed. Various representative designs of CINMs-based PTT in bone, skin and other organs are presented. Furthermore, the biosafety of CINMs is discussed. Finally, this analysis delves into the current challenges that researchers face and offers an optimistic outlook on the prospects of clinical translational research in this field. This review aims at elucidating on the applications of CINMs-based PTT and derived combination therapies in biomedicine to encourage future design and clinical translation.

Programmable site-specific delivery of an alkaline phosphatase-activatable prodrug and a mitochondria-targeted cyclopeptide for combination therapy in colon cancer

The design of advanced carriers that enable time- or stimulus-programmed drug release holds great promise to enhance the treatment efficacy in tumors. Here, hyaluronic acid (HA)-coated liposomes were designed to efficiently deliver multi-organelle-targeted and ALP/GSH dual-responsive prodrugs for combination therapy on colon tumors. In this system (designated CPTP/RA-HALipo), the unique natural cyclopeptide RA-V was linked covalently to a near-infrared (NIR) fluorophore through a disulfide linker, which was subsequently loaded in the cationic liposome core of CPTP/RA-HALipo, while the ALP-activatable phosphate CPT (CPTP) was encapsulated in the HA shell. In the tumor microenvironment, the HA shell of CPTP/RA-HALipo was partially degraded by HAase, thereby allowing the release of CPTP. The released phosphate prodrug CPTP was activated through hydrolysis of the phosphate esters by brush border-associated enzymes. The cationic liposome coated with the remaining HA could selectively enter CD44 overexpressed cells via receptor-mediated endocytosis into the lysosome, in which the acidic microenvironment degraded the liposomes to release the mitochondria-targeted theranostic agent RA-S-S-Cy. More significantly, the GSH-activatable NIR fluorescence of Cy5.5 made it possible to realize in vivo and in situ dynamic monitoring of drug release in a noninvasive manner. The organelle-specific and multi-stimuli responsive nanoparticles have shown precise control over drug delivery and release, leading to superior in vitro and/or in vivo anti-cancer efficacy. This approach represents a novel interactive drug delivery system that can synergistically differentiate the extracellular, cell membranal and intracellular targets to promote spatial and temporal control of drug release.

Photothermal therapy using graphene quantum dots

The rapid development of powerful anti-oncology medicines have been possible because of advances in nanomedicine. Photothermal therapy (PTT) is a type of treatment wherein nanomaterials absorb the laser energy and convert it into localized heat, thereby causing apoptosis and tumor eradication. PTT is more precise, less hazardous, and easy-to-control in comparison to other interventions such as chemotherapy, photodynamic therapy, and radiation therapy. Over the past decade, various nanomaterials for PTT applications have been reviewed; however, a comprehensive study of graphene quantum dots (GQDs) has been scantly reported. GQDs have received huge attention in healthcare technologies owing to their various excellent properties, such as high water solubility, chemical stability, good biocompatibility, and low toxicity. Motivated by the fascinating scientific discoveries and promising contributions of GQDs to the field of biomedicine, we present a comprehensive overview of recent progress in GQDs for PTT. This review summarizes the properties and synthesis strategies of GQDs including top-down and bottom-up approaches followed by their applications in PTT (alone and in combination with other treatment modalities such as chemotherapy, photodynamic therapy, immunotherapy, and radiotherapy). Furthermore, we also focus on the systematic study of in vitro and in vivo toxicities of GQDs triggered by PTT. Moreover, an overview of PTT along with the synergetic application used with GQDs for tumor eradication are discussed in detail. Finally, directions, possibilities, and limitations are described to encourage more research, which will lead to new treatments and better health care and bring people closer to the peak of human well-being.

A co-delivery system based on chlorin e6-loaded ROS-sensitive polymeric prodrug with self-amplified drug release to enhance the efficacy of combination therapy for breast tumor cells

Background: Recently, various combination therapies for tumors have garnered popularity because of their synergistic effects in improving therapeutic efficacy and reducing side effects. However, incomplete intracellular drug release and a single method of combining drugs are inadequate to achieve the desired therapeutic effect.

Methods: A reactive oxygen species (ROS)-sensitive co-delivery micelle (Ce6@PTP/DP). It was a photosensitizer and a ROS-sensitive paclitaxel (PTX) prodrug for synergistic chemo-photodynamic therapy. Micelles size and surface potential were measured. In vitro drug release, cytotoxicity and apoptosis were investigated.

Results: Ce6@PTP/DP prodrug micelles exhibited good colloidal stability and biocompatibility, high PTX and Ce6 loading contents of 21.7% and 7.38%, respectively. Upon light irradiation, Ce6@PTP/DP micelles endocytosed by tumor cells can generate sufficient ROS, not only leading to photodynamic therapy and the inhibition of tumor cell proliferation, but also triggering locoregional PTX release by cleaving the thioketal (TK) bridged bond between PTX and methoxyl poly (ethylene glycol). Furthermore, compared with single drug-loaded micelles, the light-triggered Ce6@PTP/DP micelles exhibited self-amplified drug release and significantly greater inhibition of HeLa cell growth.

Conclusion: The results support that PTX and Ce6 in Ce6@PTP/DP micelles exhibited synergistic effects on cell-growth inhibition. Thus, Ce6@PTP/DP micelles represent an alternative for realizing synergistic chemo-photodynamic therapy.

Tirapazamine-loaded UiO-66/Cu for ultrasound-mediated promotion of chemodynamic therapy cascade hypoxia-activated anticancer therapy

Chemodynamic therapy (CDT), an emerging oncology treatment, has received considerable attention owing to its high selectivity, less aggressiveness, and endogenous stimulation. However, the complex intra-tumor environment limits the therapeutic effect. In this study, Cu⁺ was directly doped into the structure of the UiO-66 matrix using an in situ one-pot oil bath method. The as-formed UiO-66/Cu possessed a large surface area, making it feasible to modify folic acid (FA) and carry more chemotherapeutic agents like tirapazamine (TPZ), thus forming UiO-66/Cu-FA-TPZ nanoplatforms. For CDT, the nanoplatform catalyzed the cyclic generation of the highly oxidizing hydroxyl radical (·OH) from H₂O₂. Particularly, low-frequency ultrasound enhanced the curative effect. Notably, in a tumor, a severe hypoxic environment and ultrasound can activate more TPZ for safe and efficient chemotherapy, achieving synergistic and hypoxia-activated tumor treatment with a low risk of side effects. Moreover, the nanoplatform exhibits computed tomography imaging functions for combined diagnosis and treatment. Our designed nanoplatform overcomes the dilemma of insufficient efficacy from conventional therapy attributed to a hypoxic environment, expecting to guide the design of future treatment regimens for hypoxic tumors.

Hollow Nanomaterials in Advanced Drug Delivery Systems: From Single- to Multiple Shells

Hollow-structured nanomaterials (HSNMs) have attracted increased interest in biomedical fields, owing to their excellent potential as drug delivery systems (DDSs) for clinical applications. Among HSNMs, hollow multi-shelled structures (HoMSs) exhibit properties such as high loading capacity, sequential drug release, and multi-functionalized modification and represent a new class of nanoplatforms for clinical applications. The remarkable properties of HoMS-based DDS can simultaneously satisfy and enhance DDSs for delivering small molecular drugs (e.g., antibiotics, chemotherapy drugs, and imaging agents) and macromolecular drugs (e.g., protein/peptide- and nucleic acid-based drugs). First, the latest research advances in delivering small molecular drugs are summarized and highlight the inherent advantages of HoMS-based DDSs for small molecular drug targeting, combining continuous therapeutic drug delivery and theranostics to optimize the clinical benefit. Meanwhile, the macromolecular drugs DDSs are in the initial development stage and currently offer limited delivery modes. There is a growing need to analyze the deficiency of other HSNMs and integrate the advantages of HSNMs, providing solutions for the safe, stable, and cascade delivery of macromolecular drugs to meet vast treatment requirements. Therefore, the latest advances in HoMS-based DDSs are comprehensively reviewed, mainly focusing on the characteristics, research progress by drug category, and future research prospects.

Mitochondrial-targeted nanoparticles: Delivery and therapeutic agents in cancer

Mitochondria are the powerhouses of cells and modulate the essential metabolic functions required for cellular survival. Various mitochondrial pathways, such as oxidative phosphorylation or production of reactive oxygen species (ROS) are dysregulated during cancer growth and development, rendering them attractive targets against cancer. Thus, the delivery of antitumor agents to mitochondria has emerged as a potential approach for treating cancer. Recent advances in nanotechnology have provided innovative solutions for overcoming the physical barriers posed by the structure of mitochondrial organelles, and have enabled the development of efficient mitochondrial nanoplatforms. In this review, we examine the importance of mitochondria during neoplastic development, explore the most recent smart designs of nano-based systems aimed at targeting mitochondria, and highlight key mitochondrial pathways in cancer cells.

Antioxidant, Enzyme, and H2O2-Triggered Melanoma Targeted Mesoporous Organo-Silica Nanocomposites for Synergistic Cancer Therapy

The multi-stimuli responsive drug delivery system has recently attracted attention in cancer treatments, since it can reduce several side effects and enhance cancer therapeutic efficacy. Herein, we present the intracellular antioxidant (glutathione, GSH), enzyme (hyaluronidase, HAase), and hydrogen peroxide (H2O2) triggered mesoporous organo-silica (MOS) nanocomposites for multi-modal treatments via chemo-, photothermal, and photodynamic cancer therapies. A MOS nanoparticle was synthesized by two-types of precursors, tetraethyl orthosilicate (TEOS) and bis[3-(triethoxysilyl)propyl] tetrasulfide (BTES), providing large-sized mesopores and disulfide bonds cleavable by GSH. Additionally, we introduced a new β-cyclodextrin-hyaluronic acid (CDHA) gatekeeper system, enabling nanocomposites to form the specific interaction with the ferrocene (Fc) molecule, control the drug release by the HAase and H2O2 environment, as well as provide the targeting ability against the CD44-overexpressing melanoma (B16F10) cells. Indocyanine green (ICG) and doxorubicin (Dox) were loaded in the MOS-Fc-CDHA (ID@MOS-Fc-CDHA) nanocomposites, allowing for hyperthermia and cytotoxic reactive oxygen species (ROS) under an 808 nm NIR laser irradiation. Therefore, we demonstrated that the ID@MOS-Fc-CDHA nanocomposites were internalized to the B16F10 cells via the CD44 receptor-mediated endocytosis, showing the controlled drug release by GSH, HAase, and H2O2 to enhance the cancer therapeutic efficacy via the synergistic chemo-, photothermal, and photodynamic therapy effect.

Targeting mitochondria in cancer therapy: Insight into photodynamic and photothermal therapies

Mitochondria are critical multifunctional organelles in cells that generate power, produce reactive oxygen species, and regulate cell survival. Mitochondria that are dysfunctional are eliminated via mitophagy as a way to protect cells under moderate stress and physiological conditions. However, mitophagy is a double-edged sword and can trigger cell death under severe stresses. By targeting mitochondria, photodynamic (PD) and photothermal (PT) therapies may play a role in treating cancer. These therapeutic modalities alter mitochondrial membrane potential, thereby affecting respiratory chain function and generation of reactive oxygen species promotes signaling pathways for cell death. In this regard, PDT, PTT, various mitochondrion-targeting agents and therapeutic methods could have exploited the vital role of mitochondria as the doorway to regulated cell death. Targeted mitochondrial therapies would provide an excellent opportunity for effective mitochondrial injury and accurate tumor erosion. Herein, we summarize the recent progress on the roles of PD and PT treatments in regulating cancerous cell death in relation to mitochondrial targeting and the signaling pathways involved.