A Self-Delivery Chimeric Peptide for Photodynamic Therapy Amplified Immunotherapy

Enhancing cancer immunotherapy with photodynamic therapy and nanoparticle: making tumor microenvironment hotter to make immunotherapeutic work better

Cancer immunotherapy has made tremendous advancements in treating various malignancies. The biggest hurdle to successful immunotherapy would be the immunosuppressive tumor microenvironment (TME) and low immunogenicity of cancer cells. To make immunotherapy successful, the 'cold' TME must be converted to 'hot' immunostimulatory status to activate residual host immune responses. To this end, the immunosuppressive equilibrium in TME should be broken, and immunogenic cancer cell death ought to be induced to stimulate tumor-killing immune cells appropriately. Photodynamic therapy (PDT) is an efficient way of inducing immunogenic cell death (ICD) of cancer cells and disrupting immune-restrictive tumor tissues. PDT would trigger a chain reaction that would make the TME 'hot' and have ICD-induced tumor antigens presented to immune cells. In principle, the strategic combination of PDT and immunotherapy would synergize to enhance therapeutic outcomes in many intractable tumors. Novel technologies employing nanocarriers were developed to deliver photosensitizers and immunotherapeutic to TME efficiently. New-generation nanomedicines have been developed for PDT immunotherapy in recent years, which will accelerate clinical applications.

Photodynamic Therapy and Adaptive Immunity Induced by Reactive Oxygen Species: Recent Reports

Cancer is one of the most significant causes of death worldwide. Despite the rapid development of modern forms of therapy, results are still unsatisfactory. The prognosis is further worsened by the ability of cancer cells to metastasize. Thus, more effective forms of therapy, such as photodynamic therapy, are constantly being developed. The photodynamic therapeutic regimen involves administering a photosensitizer that selectively accumulates in tumor cells or is present in tumor vasculature prior to irradiation with light at a wavelength corresponding to the photosensitizer absorbance, leading to the generation of reactive oxygen species. Reactive oxygen species are responsible for the direct and indirect destruction of cancer cells. Photodynamically induced local inflammation has been shown to have the ability to activate an adaptive immune system response resulting in the destruction of tumor lesions and the creation of an immune memory. This paper focuses on presenting the latest scientific reports on the specific immune response activated by photodynamic therapy. We present newly discovered mechanisms for the induction of the adaptive response by analyzing its various stages, and the possible difficulties in generating it. We also present the results of research over the past 10 years that have focused on improving the immunological efficacy of photodynamic therapy for improved cancer therapy.

Nanomaterials-assisted photothermal therapy for breast cancer: State-of-the-art advances and future perspectives

Breast cancer (BC) remains an enigmatic fatal modality ubiquitously prevalent in different parts of the world. Contemporary medicines face severe challenges in remediating and healing breast cancer. Due to its spatial specificity and nominal invasive therapeutic regime, photothermal therapy (PTT) has attracted much scientific attention down the lane. PTT utilizes a near-infrared (NIR) light source to irradiate the tumor target intravenously or non-invasively, which is converted into heat energy over an optical fibre. Dynamic progress in nanomaterial synthesis was achieved with specialized visual, physicochemical, biological, and pharmacological features to make up for the inadequacies and expand the horizon of PTT. Numerous nanomaterials have substantial NIR absorption and can function as efficient photothermal transducers. It is achievable to limit the wavelength range of an absorbance peak for specific nanomaterials by manipulating their synthesis, enhancing the precision and quality of PTT. Along the same lines, various nanomaterials are conjugated with a wide range of surface-modifying chemicals, including polymers and antibodies, which may modify the persistence of the nanomaterial and diminish toxicity concerns. In this article, we tend to put forth specific insights and fundamental conceptualizations on pre-existing PTT and its advances upon conjugation with different biocompatible nanomaterials working in synergy to combat breast cancer, encompassing several strategies like immunotherapy, chemotherapy, photodynamic therapy, and radiotherapy coupled with PTT. Additionally, the role or mechanisms of nanoparticles, as well as possible alternatives to PTT, are summarized as a distinctive integral aspect in this article.

Biomedical Application of Porphyrin-Based Amphiphiles and Their Self-Assembled Nanomaterials

Porphyrins have been vastly explored and applied in many cutting-edge fields with plenty of encouraging achievements because of their excellent properties. As important derivatives of porphyrins, porphyrin-based amphiphiles (PBAs) not only maintain the advanced properties of porphyrins (catalysis, imaging, and energy transfer) but also possess self-assembly and encapsulation capability in aqueous solution. Accordingly, PBAs and their self-assembles have had important roles in diagnosing and treating tumors and inflammation lesions in vivo, but not limited to these. In this article, we introduce the research progress of PBAs, including their constitution, structure design strategies, and performances in tumor and inflammation lesion diagnosis and treatments. On that basis, the defects of synthesized PBAs during their application and the possible effective strategies to overcome the limitations are also proposed. Finally, perspectives on PBAs exploration are updated based on our knowledge. We hope this review will bring researchers from various domains insights about PBAs.

Combinational photodynamic and photothermal - based therapies for melanoma in mouse models

BACKGROUND

Melanoma is a highly metastatic skin cancer with limited response to current therapies in advanced patients. To overcome resistance, novel treatments based on photodynamic and photothermal therapies (PDT and PTT, respectively) have been developed to treat melanoma in preclinical murine models. Despite success inhibiting implanted tumors' growth, there has been limited evaluation of their long-term effectiveness in preventing metastasis, recurrence, or improving survival rates.

METHODS

Combined and multidrug therapies based on PDT and/or PTT to treat cutaneous malignant melanoma in the preclinical mouse model were reviewed from 2016 onwards. PubMed® was the database in which the search was performed using mesh search algorithms resulting in fifty-one studies that comply with strict inclusion rules of screening.

RESULTS

B16 melanoma-bearing C57BLACK6 mice model was the most used to evaluate immunotherapies, chemotherapies, and targeted therapies in combination with PDT and/or PTT. Combined therapies demonstrated a synergistic effect, resulting in intense antitumor activity. The most extensively studied protocol for developing metastatic models involved the intravenous administration of malignant cells, with some combined therapies being tested. Furthermore, the review presents the composition of the nanostructures utilized for delivering the drugs and light-responsive agents and the treatment plans for each combined approach.

CONCLUSIONS

The identified mechanisms to simulate metastatic melanoma models and the therapeutic combinations may aid in evaluating the systemic protection of combined PDT and PTT-based therapies, particularly in conducting short-term preclinical experiments. Such simulations could have relevance to clinical studies.

Recent Progress in Carrier-Free Nanomedicine for Tumor Phototherapy

Safe and effective strategies are urgently needed to fight against the life-threatening diseases of various cancers. However, traditional therapeutic modalities, such as radiotherapy, chemotherapy and surgery, exhibit suboptimal efficacy for malignant tumors owing to the serious side effects, drug resistance and even relapse. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), are emerging therapeutic strategies for localized tumor inhibition, which can produce a large amount of reactive oxygen species (ROS) or elevate the temperature to initiate cell death by non-invasive irradiation. In consideration of the poor bioavailability of phototherapy agents (PTAs), lots of drug delivery systems have been developed to enhance the tumor targeted delivery. Nevertheless, the carriers of drug delivery systems inevitably bring biosafety concerns on account of their metabolism, degradation, and accumulation. Of note, carrier-free nanomedicine attracts great attention for clinical translation with synergistic antitumor effect, which is characterized by high drug loading, simplified synthetic method and good biocompatibility. In this review, the latest advances of phototherapy with various carrier-free nanomedicines are summarized, which may provide a new paradigm for the future development of nanomedicine and tumor precision therapy.

Peptide Vaccines in Melanoma: Chemical Approaches towards Improved Immunotherapeutic Efficacy

Cancer of the skin is by far the most common of all cancers. Although the incidence of melanoma is relatively low among skin cancers, it can account for a high number of skin cancer deaths. Since the start of deeper insight into the mechanisms of melanoma tumorigenesis and their strong interaction with the immune system, the development of new therapeutical strategies has been continuously rising. The high number of melanoma cell mutations provides a diverse set of antigens that the immune system can recognize and use to distinguish tumor cells from normal cells. Peptide-based synthetic anti-tumor vaccines are based on tumor antigens that elicit an immune response due to antigen-presenting cells (APCs). Although targeting APCs with peptide antigens is the most important assumption for vaccine development, peptide antigens alone are poorly immunogenic. The immunogenicity of peptide antigens can be improved not only by synthetic modifications but also by the assistance of adjuvants and/or delivery systems. The current review summarizes the different chemical approaches for the development of effective peptide-based vaccines for the immunotherapeutic treatment of advanced melanoma.

Astragalus polysaccharide: a review of its immunomodulatory effect

The Astragalus polysaccharide is an important bioactive component derived from the dry root of Astragalus membranaceus. This review aims to provide a comprehensive overview of the research progress on the immunomodulatory effect of Astragalus polysaccharide and provide valuable reference information. We review the immunomodulatory effect of Astragalus polysaccharide on central and peripheral immune organs, including bone marrow, thymus, lymph nodes, spleen, and mucosal tissues. Furthermore, the immunomodulatory effect of Astragalus polysaccharide on a variety of immune cells is summarized. Studies have shown that Astragalus polysaccharide can promote the activities of macrophages, natural killer cells, dendritic cells, T lymphocytes, B lymphocytes and microglia and induce the expression of a variety of cytokines and chemokines. The immunomodulatory effect of Astragalus polysaccharide makes it promising for the treatment of many diseases, including cancer, infection, type 1 diabetes, asthma, and autoimmune disease. Among them, the anticancer effect is the most prominent. In short, Astragalus polysaccharide is a valuable immunomodulatory medicine, but further high-quality studies are warranted to corroborate its clinical efficacy.

Multi-faced roles of reactive oxygen species in anti-tumor T cell immune responses and combination immunotherapy

T cells play a central role in anti-tumor immunity, and reactive oxygen species (ROS) lie at the crossroad on the anti-tumor T cell responses. To activate efficient T cell immunity, a moderate level of ROS is needed, however, excessive ROS would cause toxicity to the T cells, because the improper level leads to the formation and maintenance of an immunosuppressive tumor microenvironment. Up to date, strategies that modulate ROS, either increasing or decreasing, have been widely investigated. Some of them are utilized in anti-tumor therapies, showing inevitable impacts on the anti-tumor T cell immunity with both obverse and reverse sides. Herein, the impacts of ROS-increasing and ROS-decreasing treatments on the T cell responses in the tumor microenvironment are reviewed and discussed. At the same time, outcomes of combination immunotherapies are introduced to put forward inspirations to unleash the potential of immunotherapies.

Supramolecular cancer photoimmunotherapy based on precise peptide self-assembly design

Combinational photoimmunotherapy (PIT) is considered to be an ideal strategy for the treatment of highly recurrent and metastatic cancer, because it can ablate the primary tumor and provide in situ an autologous tumor vaccine to induce the host immune response, ultimately achieving the goal of controlling tumor growth and distal metastasis. Significant efforts have been devoted to enhancing the immune response caused by phototherapy-eliminated tumors. Recently, supramolecular PIT nanoagents based on precise peptide self-assembly design have been employed to improve the efficacy of photoimmunotherapy by utilizing the stability, targeting capability and flexibility of drugs, increasing tumor immunogenicity and realizing the synergistic amplification of immune effects through multiple pathways and collaborative strategy. This review summarizes peptide-based supramolecular PIT nanoagents for phototherapy-synergized cancer immunotherapy and its progress in enhancing the effect of photoimmunotherapy, especially focusing on the design of peptide-based PIT nanoagents, the progress of bioactive peptides combined photoimmunotherapy, and the synergistic immune-response mechanism.

Polymeric Nanosystems for Immunogenic Cell Death-Based Cancer Immunotherapy

Immunotherapy has pointed out a scientific and promising direction for cancer treatment through the rouse of immunosurveillance and the decrease of possible side effects in recent years. In immunotherapy, immunogenic cancer cell death (ICD) plays a critical role in regulating anti-cancer immune system in vivo via the release of damage-associated molecular patterns. ICD can not only induce in situ cancer cells apoptosis, but also arouse the immune response against metastatic tumors, which is of great clinical significance to eradicate tumors. In cancer immunotherapy, polymer nanoparticles have drawn increasing attention as an important component of ICD-based immunotherapy attributing to their controllable size, excellent biocompatibility, promising ability of protecting cargo from surrounding environment, which delivers the antigens or immune inducers to antigen-presenting cells, and further triggers sinnvoll T cell response. In this review, the recent advances in the development of polymeric material-based nanosystems for ICD-mediated cancer immunotherapy are summarized. The mechanism of ICD and some current restrictions inhibiting the efficiency of immunotherapy and future prospects are also discussed.

Assembled small organic molecules for photodynamic therapy and photothermal therapy

As a worldwide major public health problem, cancer is one of the leading causes of death. Effective treatment of cancer is an important challenge. Therefore, photodynamic therapy (PDT) and photothermal therapy (PTT) have been widely applied as anti-tumour strategies due to their high-performance and limited side effects. Inspired by natural supramolecular architectures, such as cytochromes and photosystems, the hierarchical supramolecular assembly of small organic molecules has been developed for their use as photosensitizers or photothermal agents for PDT and PTT, respectively. In this manuscript, we will summarize the recent progress of PDT and PTT based on the assembly of small organic molecules.

Nanocarrier-Based Drug Delivery for Melanoma Therapeutics

Melanoma, as a tumor cell derived from melanocyte transformation, has the characteristics of malignant proliferation, high metastasis, rapid recurrence, and a low survival rate. Traditional therapy has many shortcomings, including drug side effects and poor patient compliance, and so on. Therefore, the development of an effective treatment is necessary. Currently, nanotechnologies are a promising oncology treatment strategy because of their ability to effectively deliver drugs and other bioactive molecules to targeted tissues with low toxicity, thereby improving the clinical efficacy of cancer therapy. In this review, the application of nanotechnology in the treatment of melanoma is reviewed and discussed. First, the pathogenesis and molecular targets of melanoma are elucidated, and the current clinical treatment strategies and deficiencies of melanoma are then introduced. Following this, we discuss the main features of developing efficient nanosystems and introduce the latest reports in the literature on nanoparticles for the treatment of melanoma. Subsequently, we review and discuss the application of nanoparticles in chemotherapeutic agents, immunotherapy, mRNA vaccines, and photothermal therapy, as well as the potential of nanotechnology in the early diagnosis of melanoma.

Tumor Microenvironment-Responsive Nanomaterials as Targeted Delivery Carriers for Photodynamic Anticancer Therapy

Photodynamic therapy (PDT), as an alternative approach to treat tumors through reactive oxygen species (ROS) produced by the activated photosensitizers (PS) upon light irradiation, has attracted wide attention in recent years due to its low invasive and highly efficient features. However, the low hydrophilicity and poor targeting of PS limits the clinical application of PDT. Stimuli-responsive nanomaterials represent a major class of remarkable functional nanocarriers for drug delivery. In particular, tumor microenvironment-responsive nanomaterials (TMRNs) can respond to the special pathological microenvironment in tumor tissues to release the loaded drugs, that allows them to control the release of PS within tumor tissues. Recent studies have demonstrated that TMRNs can achieve the targeted release of PS at tumor sites, increase the concentration of PS in tumor tissues, and reduce side effects of PDT. Hence, in the present paper, we review TMRNs, mainly including pH-, redox-, enzymes-, and hypoxia-responsive smart nanomaterials, and focus on the application of these smart nanomaterials as targeted delivery carriers of PS in photodynamic anticancer therapy, to further boost the development of PDT in tumor therapy.

Self-assembling Peptides in Current Nanomedicine: Versatile Nanomaterials for Drug Delivery

BACKGROUND

The development of modern nanomedicine greatly depends on the involvement of novel materials as drug delivery system. In order to maximize the therapeutic effects of drugs and minimize their side effects, a number of natural or synthetic materials have been widely investigated for drug delivery. Among these materials, biomimetic self-assembling peptides (SAPs) have received more attention in recent years. Considering the rapidly growing number of SAPs designed for drug delivery, a summary of how SAPs-based drug delivery systems were designed, would be beneficial.

METHOD

We outlined research works on different SAPs that have been investigated as carriers for different drugs, focusing on the design of SAPs nanomaterials and how they were used for drug delivery in different strategies.

RESULTS

Based on the principle rules of chemical complementarity and structural compatibility, SAPs such as ionic self-complementary peptide, peptide amphiphile and surfactant-like peptide could be designed. Determined by the features of peptide materials and the drugs to be delivered, different strategies such as hydrogel embedding, hydrophobic interaction, electrostatic interaction, covalent conjugation or the combination of them could be employed to fabricate SAPs-drug complex, which could achieve slow release, targeted or environment-responsive delivery of drugs. Furthermore, some SAPs could also be combined with other types of materials for drug delivery, or even act as drug by themselves.

CONCLUSION

Various types of SAPs have been designed and used for drug delivery following various strategies, suggesting that SAPs as a category of versatile nanomaterials have promising potential in the field of nanomedicine.

Recent progress in supramolecular peptide assemblies as virus mimics for cancer immunotherapy

Supramolecular peptide assemblies can mimic natural viruses and serve as well-defined, dynamic and multifunctional nanoplatforms for cancer immunotherapy, where the peptide segments act as antigens, adjuvants and carriers.