Engineered Cell-Assisted Photoactive Nanoparticle Delivery for Image-Guided Synergistic Photodynamic/Photothermal Therapy of Cancer

Poly(Glutamic Acid)-Engineered Nanoplatforms for Enhanced Cancer Phototherapy

Phototherapies, including photothermal therapy and photodynamic therapy, have gained booming development over the past several decades for their attractive non-invasiveness nature, negligible adverse effects, minimal systemic toxicity, and high spatial selectivity. Phototherapy usually requires three components: light irradiation, photosensitizers, and molecular oxygen. Photosensitizers can convert light energy into heat or reactive oxygen species, which can be used in the tumor-killing process. The direct application of photosensitizers in tumor therapy is restricted by their poor water solubility, fast clearance, severe toxicity, and low cellular uptake. The encapsulation of photosensitizers into nanostructures is an attractive strategy to overcome these critical limitations. Poly(glutamic acid) (PGA) is a kind of poly(amino acid)s containing the repeating units of glutamic acid. PGA has superiority for cancer treatment because of its good biocompatibility, low immunogenicity, and modulated pH responsiveness. The hydrophilicity nature of PGA allows the physical entrapment of photosensitizers and anticancer drugs via the construction of amphiphilic polymers. Moreover, the pendent carboxyl groups of PGA enable chemical conjugation with therapeutic agents. In this mini-review, we highlight the stateof- the-art design and fabrication of PGA-based nanoplatforms for phototherapy. We also discuss the potential challenges and future perspectives of phototherapy, and clinical translation of PGA-based nanomedicines.

Recent Advances of Diketopyrrolopyrrole Derivatives in Cancer Therapy and Imaging Applications

Cancer is threatening the survival of human beings all over the world. Phototherapy (including photothermal therapy (PTT) and photodynamic therapy (PDT)) and bioimaging are important tools for imaging-mediated cancer theranostics. Diketopyrrolopyrrole (DPP) dyes have received more attention due to their high thermal and photochemical stability, efficient reactive oxygen species (ROS) generation and thermal effects, easy functionalization, and tunable photophysical properties. In this review, we outline the latest achievements of DPP derivatives in cancer therapy and imaging over the past three years. DPP-based conjugated polymers and small molecules for detection, bioimaging, PTT, photoacoustic imaging (PAI)-guided PTT, and PDT/PTT combination therapy are summarized. Their design principles and chemical structures are highlighted. The outlook, challenges, and future opportunities for the development of DPP derivatives are also presented, which will give a future perspective for cancer treatment.

Macrophage-mediated delivery of Fe3O4-nanoparticles: a generalized strategy to deliver iron to Tumor Microenvironment

Background：Iron are used to alter macrophage phenotypes and induce tumor cell death. Iron oxide nanoparticles can induce macrophage polarization into the M1 phenotype, which inhibits tumor growth and can dissociate into iron ions in macrophages. Objective：In this study, we proposed to construct high expression of Ferroportin1 macrophages as carriers to deliver Fe3O4-nanoparticles and iron directly to tumor sites.

METHODS

Three sizes of Fe3O4-nanoparticles with gradient concentrations were used. The migration ability of iron-carrying macrophages was confirmed by an in vitro migration experiment and monocyte chemoattractant protein-1 detection. The release of iron from macrophages was confirmed by determining their levels in the cell culture supernatant, and we constructed a high expression of ferroportin strain of macrophage lines to increase intracellular iron efflux by increasing membrane transferrin expression. Fe3O4-NPs in Ana-1 cells were degraded in lysosomes, and the amount of iron released was correlated with the expression of ferroportin1.

RESULTS

After Fe3O4-nanoparticles uptake by macrophages, not only polarized macrophages into M1 phenotype, but the nanoparticles also dissolved in the lysosome and iron were released out of the cell. FPN1 has known as the only known Fe transporter, we use Lentiviral vector carrying FPN1 gene transfected into macrophages, has successfully constructed Ana-1-FPN1 cells, and maintains high expression of FPN1. Ana-1-FPN1 cells increases intracellular iron release. Fe3O4-nanoparticles loaded engineered Ana-1 macrophages can act as a "reservoir" of iron.

CONCLUSION

Our study provides proof of strategy for Fe3O4-NPs target delivery to the tumor microenvironment. Moreover, increase of intracellular iron efflux by overexpression of FPN1, cell carriers can act as a reservoir for iron, providing the basis for targeted delivery of Fe3O4-NPs and iron ions in vivo.

Novel Water-Soluble Phthalocyanine-Based Small Molecule for Effective NIR Triggered Dual Phototherapy of Cancer

Photothermal therapy (PTT) synergized photodynamic therapy (PDT) indicates more hopeful future of clinical application and is of significant importance for cancer theranostic compared with monotherapy. Dual phototherapy is attracting increasing...

A metformin-based nanoreactor alleviates hypoxia and reduces ATP for cancer synergistic therapy

Severe hypoxia in solid tumors limits the efficacy of oxygen (O₂)-dependent photodynamic therapy (PDT). The overexpressed heat shock proteins (HSPs) in tumor cells hamper the effect of photothermal therapy (PTT). Herein, a tumor oxygenation-enhanced and ATP-reduced gelatin nanoreactor (MCGPD ∼ RGD NPs) for PDT/PTT-augmented combination cancer therapy is reported. In this nanosystem, the Arg-Gly-Asp (RGD) peptides of MCGPD ∼ RGD NPs can ensure accurate recognition and sufficient accumulation in the tumor site. After accumulation, doxorubicin (DOX) can be released from MCGPD ∼ RGD NPs in a mild acidic tumor microenvironment (TME) for highly efficient chemotherapy. Upon 808 nm laser irradiation, the overexpressed matrix metalloproteinase-2 (MMP-2) in the TME and the heat produced from the PDA coating trigger Gel NP degradation to expose chlorin e6 (Ce6) and Met from the cavity of MCGPD ∼ RGD NPs. The exposed Met elevates the O₂ content and reduces ATP production in tumor sites to spur the successful O₂-dependent PDT and HSP-mediated PTT. The heat generated by the PDA coating directly kills the tumor cells to ensure PTT and amplifies the chemotherapeutic effect. In vitro and in vivo assays indicate that MCGPD ∼ RGD NPs have excellent ability to promote cell apoptosis and to inhibit tumor growth. Overall, this smart responsive hydrogel nanosystem with hypoxia-relieving capacity and ATP-decreasing performance provides a promising strategy against cancer.

Diatom-like silica-protein nanocomposites for sustained drug delivery of ruthenium polypyridyl complexes

Inspired by the unique glass cell wall of diatom, we design a new nanostructure of human serum albumin nanoparticle (HSANP) coated with silica (HSA/SiO₂), which consists of a core-satellite assembly of small silica nanoparticles on a single HSANP. The HSA/SiO₂ nanoparticles are used for delivering ruthenium polypyridyl complexes into cells. The silica coating increases the Ru loading efficiency, and prevents the burst release of Ru from HSA/SiO₂. The Ru release rate can be controlled by adjusting the amount of coated silica on HSANP, affording a drug delivery system with controlled drug release rate. The Ru-HSA/SiO₂ nanoparticles show high stability in physiological condition, and significantly increase the Ru uptake into cells, which proceeds via clathrin-mediated endocytosis into the lysosomes. The silica coating takes no effect on the fluorescence intensity and ROS generation of loaded Ru in HSA/SiO₂. Furthermore, Ru4-HSA/SiO₂ exhibit weak cytotoxicity in dark, however, the nanodrug can be activated by light irradiation and generate ROS to damage cells, thus achieving an excellent photodynamic therapy efficiency. Therefore, the diatom-like nanostructure can function as sustained drug delivery nanocarrier of ruthenium polypyridyl complex and can be used for bioimaging and photodynamic therapy.

A Novel D-A-D Photosensitizer for Efficient NIR Imaging and Photodynamic Therapy

Photodynamic therapy (PDT) has attracted great interest in cancer theranostics owing to its minimal invasiveness and low side effect. In PDT, photosensitizers are indispensable components that generate cytotoxic reactive oxygen species (ROS). Tremendous efforts have been devoted to optimizing the photosensitizer with enhanced ROS efficiency. However, to improve the precision and controllability for PDT, developing NIR imaging-guided photosensitizers are still urgent and challenging. Here, we have designed a novel photosensitizer 2Cz-BTZ which integrated with intense NIR emission and photoinduced singlet oxygen ¹ O₂ generation capabilities. Moreover, after loading the photosensitizers 2Cz-BTZ into biocompatible amphiphilic polymers F127, the formed 2Cz-BTZ@F127 nanoparticles (NPs) exhibited good photoinduced therapy as well as long-term in vivo imaging capabilities. Under these merits, the 2Cz-BTZ@F127 NPs showed NIR imaging-guided PDT, which paves a promising way for spatiotemporally precise tumor theranostics.

Photoactivatable metabolic warheads enable precise and safe ablation of target cells in vivo

Photoactivatable molecules enable ablation of malignant cells under the control of light, yet current agents can be ineffective at early stages of disease when target cells are similar to healthy surrounding tissues. In this work, we describe a chemical platform based on amino-substituted benzoselenadiazoles to build photoactivatable probes that mimic native metabolites as indicators of disease onset and progression. Through a series of synthetic derivatives, we have identified the key chemical groups in the benzoselenadiazole scaffold responsible for its photodynamic activity, and subsequently designed photosensitive metabolic warheads to target cells associated with various diseases, including bacterial infections and cancer. We demonstrate that versatile benzoselenadiazole metabolites can selectively kill pathogenic cells - but not healthy cells - with high precision after exposure to non-toxic visible light, reducing any potential side effects in vivo. This chemical platform provides powerful tools to exploit cellular metabolic signatures for safer therapeutic and surgical approaches.

Solutions to the Drawbacks of Photothermal and Photodynamic Cancer Therapy

Phototherapy such as photothermal therapy and photodynamic therapy in cancer treatment has been developed quickly over the past few years for its noninvasive nature and high efficiency. However, there are still many drawbacks in phototherapy that prevent it from clinical applications. Thus, scientists have designed different systems to overcome the issues associated with phototherapy, including enhancing the targeting ability of phototherapy, low-temperature photothermal therapy, replacing near-infrared light with other excitation sources, and so on. This article discusses the problems and shortcomings encountered in the development of phototherapy and highlights possible solutions to address them so that phototherapy may become a useful cancer treatment approach in clinical practice. This article aims to give a brief summary about current research advancements in phototherapy research and provides a quick guideline toward future developments in the field.

An "all-in-one" strategy based on the organic molecule DCN-4CQA for effective NIR-fluorescence-imaging-guided dual phototherapy

Dual phototherapy combining photodynamic therapy (PDT) and photothermal therapy (PTT) is considered to be a more effective therapeutic method against cancer than single treatment. Therefore, the development of a single material with both near-infrared (NIR)-laser-triggered PDT and PTT abilities is highly desirable but remains a great challenge. A design philosophy for photosensitizers for integrated PDT and PTT treatment has been put forward: (1) a high molar extinction coefficient in the NIR region; (2) suitable LUMO and T1 energy levels to regulate intersystem crossing for effective singlet oxygen (1O2) generation for PDT; and (3) the suppression of fluorescence emission to enhance the process of nonradiative transition with appropriate chemical modifications. Herein, an "all-in-one" functional material, di-cyan substituted 5,12-dibutylquinacridone (DCN-4CQA), for diagnosis and therapy was obtained. DCN-4CQA possesses dual-functional phototherapeutic activity and NIR fluorescence and it was produced via a facile synthesis process from the classic organic photoelectric material quinacridone. We then prepared smart water-soluble nanoparticles (NPs), DCN-4CQA/F127, using Pluronic® 127 (F127) as a drug carrier. The NPs exhibited excellent biocompatibility, robust photostability, NIR fluorescence, a high photothermal conversion efficiency (η = 47.3%), and sufficient 1O2 generation (ΦΔ = 24.3%) under NIR laser irradiation. Remarkably, the DCN-4CQA/F127 NPs significantly inhibited tumor growth in mice subjected to NIR laser irradiation. This study provides a new route for the development of highly efficient, low-cytotoxicity photosensitizers for fluorescence-imaging-guided PTT/PDT.

Augmented Graphene Quantum Dot-Light Irradiation Therapy for Bacteria-Infected Wounds

This paper proposes a highly efficient antibacterial system based on a synergistic combination of photodynamic therapy, photothermal therapy, and chemotherapy. Chitosan oligosaccharide functionalized graphene quantum dots (GQDs-COS) with short-term exposure to 450 nm visible light are used to promote rapid healing in bacteria-infected wounds. The GQDs undergo strong photochemical transformation to rapidly produce radical oxygen species and heat under light illumination, while the COS has an innate antimicrobial ability. Moreover, the positively charged GQDs-COS can easily capture bacteria via electrostatic interactions and kill Gram-positive and Gram-negative bacteria by multivalent interactions and synergistic effects. The antibacterial action of this nanocomposite causes irreversible damage to outer and inner bacterial membranes, resulting in cytoplasm leakage and death. The system has good hemocompatibility and low cytotoxicity and can improve the healing of infected wounds, as demonstrated by the examination of pathological tissue sections and inflammatory markers. These results suggest that GQDs anchored with bioactive molecules are a potential photo-activated antimicrobial strategy for anti-infective therapy.

Distribution, Trafficking, and in Vitro Photodynamic Therapy Efficacy of Cholesterol Silicon(IV) Phthalocyanine and Its Nanoparticles in Breast Cancer Cells

A cholesterol silicon(IV) phthalocyanine (Chol-Pc) and a water-soluble Chol-Pc based nanoparticle (DSPE@Chol-Pc), which was prepared using 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(poly(ethylene glycol))-2000] (DSPE-PEG₂₀₀₀) as a nanocarrier were developed. Chol-Pc readily distributed within the cholesterol-rich domains and was preferentially localized in the Golgi apparatus after being transported into the cells. The trafficking of DSPE@Chol-Pc in breast cancer cells was visualized by tracking the fluorescence of Chol-Pc and FITC-labeled DSPE-PEG₂₀₀₀ through two-photonic imaging in real-time. It was discovered that Chol-Pc disassociated from the DSPE-PEG₂₀₀₀ on the plasma membrane and traveled to the cholesterol-rich domains soon afterward. Both DSPE@Chol-Pc and Chol-Pc effectively mediated photodynamic therapy to kill the breast cancer cells. After light irradiation, we found that the organizations of clustered cholesterol-rich domains in cells were destroyed, presumably leading to the death of cells for photodynamic therapy. It should be noted that DSPE@Chol-Pc is highly soluble in aqueous solution and has strong red fluorescence under two-photon excitation. Thus, it could be an excellent probe for detecting cholesterol-rich domains and studying transport processes of cholesterol in living cells.