Anti-Tumor Metastasis via Platelet Inhibitor Combined with Photothermal Therapy under Activatable Fluorescence/Magnetic Resonance Bimodal Imaging Guidance

Platelet-Based Nanoparticles with Stimuli-Responsive for Anti-Tumor Therapy

In addition to hemostasis and coagulation, years of studies have proved that platelets are involved in the whole process of tumor progression, including tumor invasion, intravasation, extravasation, and so on. It means that this property of platelets can be used in anti-tumor therapy. However, traditional platelet-based antitumor drugs often cause autologous platelet damage due to lack of targeting, resulting in serious side effects. Therefore, the researchers designed a variety of anti-tumor drug delivery systems based on platelets by targeting platelets or platelet membrane coating. The drug delivery systems have special response modes, which is crucial in the design of nanoparticles. These modes enhance the targeting and improve the anti-tumor effect. Here, we present a review of recent discoveries in the field of the crosstalk between platelets and tumors and the progress of platelet-based anti-tumor nanoparticles.

Nanoparticle-based drug delivery systems to enhance cancer immunotherapy in solid tumors

Immunotherapy has developed rapidly in solid tumors, especially in the areas of blocking inhibitory immune checkpoints and adoptive T-cell transfer for immune regulation. Many patients benefit from immunotherapy. However, the response rate of immunotherapy in the overall population are relatively low, which depends on the characteristics of the tumor and individualized patient differences. Moreover, the occurrence of drug resistance and adverse reactions largely limit the development of immunotherapy. Recently, the emergence of nanodrug delivery systems (NDDS) seems to improve the efficacy of immunotherapy by encapsulating drug carriers in nanoparticles to precisely reach the tumor site with high stability and biocompatibility, prolonging the drug cycle of action and greatly reducing the occurrence of toxic side effects. In this paper, we mainly review the advantages of NDDS and the mechanisms that enhance conventional immunotherapy in solid tumors, and summarize the recent advances in NDDS-based therapeutic strategies, which will provide valuable ideas for the development of novel tumor immunotherapy regimen.

Tumor Therapy Strategies Based on Microenvironment-Specific Responsive Nanomaterials

The tumor microenvironment (TME) is a complex and variable region characterized by hypoxia, low pH, high redox status, overexpression of enzymes, and high-adenosine triphosphate concentrations. In recent years, with the continuous in-depth study of nanomaterials, more and more TME-specific response nanomaterials are used for tumor treatment. However, the complexity of the TME causes different types of responses with various strategies and mechanisms of action. Aiming to systematically demonstrate the recent advances in research on TME-responsive nanomaterials, this work summarizes the characteristics of TME and outlines the strategies of different TME responses. Representative reaction types are illustrated and their merits and demerits are analyzed. Finally, forward-looking views on TME-response strategies for nanomaterials are presented. It is envisaged that such emerging strategies for the treatment of cancer are expected to exhibit dramatic trans-clinical capabilities, demonstrating the extensive potential for the diagnosis and therapy of cancer.

Tailoring mSiO2-SmCox nanoplatforms for magnetic/photothermal effect-induced hyperthermia therapy

Hyperthermia therapy is a hotspot because of its minimally invasive treatment process and strong targeting effect. Herein, a synergistic magnetic and photothermal therapeutic nanoplatform is rationally constructed. The well-dispersive mSiO2-SmCox nanoparticles (NPs) were synthesized through a one-step procedure with the regulated theoretical molar ratio of Sm/Co among 1:1, 1:2, and 1:4 for controlling the dispersion and magnetism properties of SmCox NPs in situ growth in the pore structure of mesoporous SiO2 (mSiO2), where mSiO2 with diverse porous structures and high specific surface areas serving for locating the permanent magnetic SmCox NPs. The mSiO2-SmCox (Sm/Co = 1:2) NPs with highly dispersed and uniform morphology has an average diameter of ∼73.08 nm. The photothermal conversion efficiency of mSiO2-SmCox (Sm/Co = 1:2) NPs was determined to be nearly 41%. The further in vitro and in vivo anti-tumor evaluation of mSiO2-SmCox (Sm/Co = 1:2) NPs present promising potentials for hyperthermia-induced tumor therapy due to magnetic and photothermal effects.

Fibronectin-targeting and metalloproteinase-activatable smart imaging probe for fluorescence imaging and image-guided surgery of breast cancer

Residual lesions in the tumor bed have been a challenge for conventional white-light breast-conserving surgery. Meanwhile, lung micro-metastasis also requires improved detection methods. Intraoperative accurate identification and elimination of microscopic cancer can improve surgery prognosis. In this study, a smart fibronectin-targeting and metalloproteinase-activatable imaging probe CREKA-GK8-QC is developed. CREKA-GK8-QC possesses an average diameter of 21.7 ± 2.5 nm, excellent MMP-9 protein responsiveness and no obvious cytotoxicity. In vivo experiments demonstrate that NIR-I fluorescence imaging of CREKA-GK8-QC precisely detects orthotopic breast cancer and micro-metastatic lesions (nearly 1 mm) of lungs with excellent imaging contrast ratio and spatial resolution. More notably, fluorescence image-guided surgery facilitates complete resection and avoids residual lesions in the tumor bed, improving survival outcomes. We envision that our newly developed imaging probe shows superior capacity for specific and sensitive targeted imaging, as well as providing guidance for accurate surgical resection of breast cancer.

Bioactive inorganic nanomaterials for cancer theranostics

Bioactive materials are a special class of biomaterials that can react in vivo to induce a biological response or regulate biological functions, thus achieving a better curative effect than traditional inert biomaterials. For cancer theranostics, compared with organic or polymer nanomaterials, inorganic nanomaterials possess unique physical and chemical properties, have stronger mechanical stability on the basis of maintaining certain bioactivity, and are easy to be compounded with various carriers (polymer carriers, biological carriers, etc.), so as to achieve specific antitumor efficacy. After entering the nanoscale, due to the nano-size effect, high specific surface area and special nanostructures, inorganic nanomaterials exhibit unique biological effects, which significantly influence the interaction with biological organisms. Therefore, the research and applications of bioactive inorganic nanomaterials in cancer theranostics have attracted wide attention. In this review, we mainly summarize the recent progress of bioactive inorganic nanomaterials in cancer theranostics, and also introduce the definition, synthesis and modification strategies of bioactive inorganic nanomaterials. Thereafter, the applications of bioactive inorganic nanomaterials in tumor imaging and antitumor therapy, including tumor microenvironment (TME) regulation, catalytic therapy, gas therapy, regulatory cell death and immunotherapy, are discussed. Finally, the biosafety and challenges of bioactive inorganic nanomaterials are also mentioned, and their future development opportunities are prospected. This review highlights the bioapplication of bioactive inorganic nanomaterials.

Recent advances of CREKA peptide-based nanoplatforms in biomedical applications

Nanomedicine technology is a rapidly developing field of research and application that uses nanoparticles as a platform to facilitate the diagnosis and treatment of diseases. Nanoparticles loaded with drugs and imaging contrast agents have already been used in clinically, but they are essentially passive delivery carriers. To make nanoparticles smarter, an important function is the ability to actively locate target tissues. It enables nanoparticles to accumulate in target tissues at higher concentrations, thereby improving therapeutic efficacy and reducing side effects. Among the different ligands, the CREKA peptide (Cys-Arg-Glu-Lys-Ala) is a desirable targeting ligand and has a good targeting ability for overexpressed fibrin in different models, such as cancers, myocardial ischemia-reperfusion, and atherosclerosis. In this review, the characteristic of the CREKA peptide and the latest reports regarding the application of CREKA-based nanoplatforms in different biological tissues are described. In addition, the existing problems and future application perspectives of CREKA-based nanoplatforms are also addressed.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Stimuli-Responsive Drug Delivery Systems for the Diagnosis and Therapy of Lung Cancer

Lung cancer is the most commonly diagnosed cancer and the leading cause of cancer death worldwide. Numerous drugs have been developed to treat lung cancer patients in recent years, whereas most of these drugs have undesirable adverse effects due to nonspecific distribution in the body. To address this problem, stimuli-responsive drug delivery systems are imparted with unique characteristics and specifically deliver loaded drugs at lung cancer tissues on the basis of internal tumor microenvironment or external stimuli. This review summarized recent studies focusing on the smart carriers that could respond to light, ultrasound, pH, or enzyme, and provided a promising strategy for lung cancer therapy.

Bidirectional Interaction Between Cancer Cells and Platelets Provides Potential Strategies for Cancer Therapies

Platelets are essential components in the tumor microenvironment. For decades, clinical data have demonstrated that cancer patients have a high risk of thrombosis that is associated with adverse prognosis and decreased survival, indicating the involvement of platelets in cancer progression. Increasing evidence confirms that cancer cells are able to induce production and activation of platelets. Once activated, platelets serve as allies of cancer cells in tumor growth and metastasis. They can protect circulating tumor cells (CTCs) against the immune system and detachment-induced apoptosis while facilitating angiogenesis and tumor cell adhesion and invasion. Therefore, antiplatelet agents and platelet-based therapies should be developed for cancer treatment. Here, we discuss the mechanisms underlying the bidirectional cancer-platelet crosstalk and platelet-based therapeutic approaches.