Hypericin-Loaded Carbon Nanohorn Hybrid for Combined Photodynamic and Photothermal Therapy in Vivo

Hypericin and its anticancer effects: From mechanism of action to potential therapeutic application

BACKGROUND

Emerging studies indicate that hypericin has diverse pharmacological actions and exhibits potential for treatment of various types of cancer.

PURPOSE

The current review evaluates the pharmacological activity, associated molecular mechanism, and therapeutic application of hypericin as an anticancer agent according to the most recent state of knowledge with special emphasis on clinical trials and safety profile.

METHOD

This review follows The Preferred Reporting Items for Systematic Reviews criteria. Various databases, including PubMed, Scopus and Science Direct, were used to search and collect relevant literature. The major keywords used included the following: cancer, distribution, property, signaling pathway, pharmacological effect, treatment, prevention, in vitro and in vivo studies, toxicity, bioavailability, and clinical trials.

RESULTS

One hundred three articles met the established inclusion and exclusion criteria. Hypericin has shown anticancer activity against the expansion of several cell types including breast cancer, cervical cancer, colorectal cancer, colon cancer, hepatocellular carcinoma, stomach carcinoma, leukemia, lung cancer, melanoma, and glioblastoma cancer. Hypericin exerts its anticancer activity by inhibiting pro-inflammatory mediators, endothelial growth factor, fibroblast growth factor, cell adhesion, angiogenesis, and mitochondrial thioredoxin. It has also been shown to cause an increase in the levels of caspase-3 and caspase-4, arrest the cell cycle at metaphase leading to cancer cell apoptosis, and affect various protein and gene expression patterns.

CONCLUSION

Hypericin exhibits significant inhibitory activity against various types of in vitro and in vivo cancer models. However, well-designed, high quality, large-scale and multi-center randomized clinical studies are required to establish the safety and clinical utility of hypericin in cancer patients.

NIR-II-Responsive CeO2-x@HA Nanotheranostics for Photoacoustic Imaging-Guided Sonodynamic-Enhanced Synergistic Phototherapy

The therapeutic effect of photothermal therapy (PTT) and photodynamic therapy (PDT) is severely limited because of the shallow tissue penetration depth of the first near-infrared (NIR-I) light. Multifunctional nanotheranostics irradiated by the second near-infrared (NIR-II) light have received wide interest with respect to deeper tissue penetration, and sonodynamic therapy (SDT) synergistic phototherapy can achieve the complete elimination of tumors. Herein, we successfully constructed a single NIR-II light-induced nanotheranostic using cerium oxide (CeO_2-x) with abundant oxygen vacancies for photoacoustic imaging-guided SDT-enhanced phototherapy for the first time. CeO_2-x with surface crystalline disorder showed extensive NIR-II region absorption and an outstanding photothermal conversion ability. In addition, the CeO_2-x layer with numerous oxygen defects can promote the separation of holes and electrons by ultrasound irradiation, which can remarkably enhance the efficacy of phototherapy to achieve high-efficiency tumor ablation. CeO_2-x was surface modified with hyaluronic acid (HA) to prepare CeO_2-x@HA to allow active tumor targeting efficiency. Both cell and animal experiments confirmed that all-in-one CeO_2-x@HA exhibited a high therapeutic efficacy of SDT-enhanced PDT/PTT under 1064 nm laser irradiation, which achieved complete tumor eradication without systemic toxicity. This study significantly broadened the application of NIR-II-responsive CeO_2-x for photoacoustic imaging-mediated SDT-enhanced phototherapy to the highly efficient and precise elimination of tumors.

Porphyrin-lipid nanovesicles (Porphysomes) are effective photosensitizers for photodynamic therapy

Porphysomes (PS) are liposome-like nanoparticles comprising pyropheophorbide-conjugated phospholipids that have demonstrated potential as multimodal theranostic agents for applications that include phototherapies, targeted drug delivery and in vivo fluorescence, photoacoustic, magnetic resonance or positron emission imaging. Previous therapeutic applications focused primarily on photothermal therapy (PTT) and suggested that PSs require target-triggered activation for use as photodynamic therapy (PDT) sensitizers. Here, athymic nude mice bearing subcutaneous A549 human lung tumors were randomized into treatment and control groups: PS-PDT at various doses, PS-only and no treatment negative controls, as well as positive controls using the clinical photosensitizer Photofrin. Animals were followed for 30 days post-treatment. PS-PDT at all doses demonstrated a significant tumor ablative effect, with the greatest effect seen with 10 mg/kg PS at a drug-light interval of 24 h. By comparison, negative controls (PS-only, Photofrin-only, and no treatment) showed uncontrolled tumor growth. PDT with Photofrin at 5 mg/kg and PS at 10 mg/kg demonstrated similar tumor growth suppression and complete tumor response rates (15 vs. 25%, p = 0.52). Hence, porphysome nanoparticles are an effective PDT agent and have the additional advantages of multimodal diagnostic and therapeutic applications arising from their intrinsic structure. Porphysomes may also be the first single all-organic agent capable of concurrent PDT and PTT.

Synergistic photodynamic and photothermal therapy of BODIPY-conjugated hyaluronic acid nanoparticles

The combination of photodynamic therapy (PDT) and photothermal therapy (PTT) has emerged as a promising strategy for complete tumor ablation therapy. Herein, a boron dipyrromethene (BODIPY)-conjugated hyaluronic acid polymer that can self-assemble to form the nanoparticles (BODIPY-HA NPs) was prepared for combined cancer PDT and PTT. The fluorescence emission and reactive oxygen species (ROS) generation of BODIPY-HA NPs were inhibited because of the π-π stacking behavior of BODIPY, resulting in photothermal effect under 808 nm light irradiation. Upon the internalization by cancer cells, the BODIPY-HA NPs could disassemble into BODIPY-HA molecules, with the recovery of the fluorescence and ROS generation for PDT. Importantly, in vitro results confirmed that combined PTT and PDT have exhibited better anticancer effect than PTT alone upon 808 nm laser irradiation. These results showed that the self-assembled BODIPY-HA NPs may be a promising nanomedicine for synergistic cancer PDT and PTT.

Tumor-Targeting Multifunctional Nanoprobe for Enhanced Photothermal/Photodynamic Therapy of Liver Cancer

Numerous researchers have committed to the development of combined therapy strategies for tumors, since their use in the treatment of tumors has more ideal therapeutic outcomes. In the study, we designed and prepared gold nanostars with CD147 modified on the surface and then efficiently loaded a photosensitive drug IR820 to construct a multifunctional nanoprobe. Due to the protection effect of gold, the nanoprobe has oxygen/heat energy generation capability and can also efficiently deliver the loaded drugs inside the tumor cells. Moreover, the nanoprobe has excellent photothermal/photodynamic therapeutic outcomes. The observation by photoacoustic real-time imaging validated the outstanding tumor-targeting characteristics of our nanoprobe. Finally, in the in vivo treatment experiment, the nanoprobe achieved ideal tumor-suppressive effects after the photothermal/photodynamic therapy. In summary, the findings of this experiment are useful in the development of new combined tumor therapy strategies based on nanomaterials.

Green Approaches to Carbon Nanostructure-Based Biomaterials

The family of carbon nanostructures comprises several members, such as fullerenes, nano-onions, nanodots, nanodiamonds, nanohorns, nanotubes, and graphene-based materials. Their unique electronic properties have attracted great interest for their highly innovative potential in nanomedicine. However, their hydrophobic nature often requires organic solvents for their dispersibility and processing. In this review, we describe the green approaches that have been developed to produce and functionalize carbon nanomaterials for biomedical applications, with a special focus on the very latest reports.

Carbon Nanohorns as Effective Nanotherapeutics in Cancer Therapy

Different carbon nanostructures have been explored as functional materials for the development of effective nanomaterials in cancer treatment applications. This review mainly aims to discuss the features, either strength or weakness, of carbon nanohorn (CNH), carbon conical horn-shaped nanostructures of sp2 carbon atoms. The interest for these materials arises from their ability to couple the clinically relevant properties of carbon nanomaterials as drug carriers with the negligible toxicity described in vivo. Here, we offer a comprehensive overview of the recent advances in the use of CNH in cancer treatments, underlining the benefits of each functionalization route and approach, as well as the biological performances of either loaded and unloaded materials, while discussing the importance of delivery devices.

Smart Responsive Nanoformulation for Targeted Delivery of Active Compounds From Traditional Chinese Medicine

Traditional Chinese medicine (TCM) has been used to treat disorders in China for ~1,000 years. Growing evidence has shown that the active ingredients from TCM have antibacterial, antiproliferative, antioxidant, and apoptosis-inducing features. However, poor solubility and low bioavailability limit clinical application of active compounds from TCM. “Nanoformulations” (NFs) are novel and advanced drug-delivery systems. They show promise for improving the solubility and bioavailability of drugs. In particular, “smart responsive NFs” can respond to the special external and internal stimuli in targeted sites to release loaded drugs, which enables them to control the release of drug within target tissues. Recent studies have demonstrated that smart responsive NFs can achieve targeted release of active compounds from TCM at disease sites to increase their concentrations in diseased tissues and reduce the number of adverse effects. Here, we review “internal stimulus–responsive NFs” (based on pH and redox status) and “external stimulus–responsive NFs” (based on light and magnetic fields) and focus on their application for active compounds from TCM against tumors and infectious diseases, to further boost the development of TCM in modern medicine.

Injectable In Situ Self-Cross-Linking Hydrogels Based on Hemoglobin, Carbon Quantum Dots, and Sodium Alginate for Real-Time Detection of Wound Bacterial Infection and Efficient Postoperative Prevention of Tumor Recurrence

Postoperative wound repair of solid tumors resection, which is afflicted by the complex tumor microenvironment (TME) and associated with the bacterial infection, is worsening and demands prompt solutions. Meanwhile, the tumor recurrence is frequently seen during the subsequent treatment due to intraoperative bleeding. For effective postoperative cancer therapy, nanoscale carriers occur as innovative and sensitive tools for monitoring the wound state, avoiding bacterial infection, and restraining tumor recurrence. Herein, a multifunctional sodium alginate (SA) hydrogel immobilizing hemoglobin (Hb) and pH-sensitive fluorescent changing carbon quantum dots (CQDs) is rationally designed. The multifunctionalization of obtained alginate@hemoglobin@CQDs hydrogel (SA@Hb@CQDs) simultaneously consists of detection, hemostasis, and chemodynamic therapy (CDT) with monitoring of wound pH based on CQDs, stanching triggered from SA hydrogel, and Fenton reaction induced by Hb. We demonstrated that SA@Hb@CQDs can stop bleeding quickly, collect wound status information in real-time, and avert bacterial infection as well as inhibit local tumor recurrence effectively. Therefore, our work provides a promising combination approach for postoperative tumor therapy.