Smart pH-Responsive Nanocube-Controlled Delivery of DNA Vaccine and Chemotherapeutic Drugs for Chemoimmunotherapy

Challenges and progress toward tumor-targeted therapy by systemic delivery of polymer-complexed oncolytic adenoviruses

Oncolytic adenovirus (oAd) elicits antitumor activity by preferential viral replication in cancer cells. However, poor systemic administrability or suboptimal intratumoral retainment of the virus remains a major challenge toward maximizing the antitumor activity of oAd in a clinical environment. To surmount these issues, a variety of non-immunogenic polymers has been used to modify the surface of oAds chemically or physically. Complexation of oAd with polymers can effectively evade the host immune response and reduces nonspecific liver sequestration. The tumor-specific delivery of these complexes can be further improved upon by inclusion of tumor-targeting moieties on the surface. Therefore, modification of the Ad surface using polymers is viewed as a potential strategy to enhance the delivery of Ad via systemic administration. This review aims to provide a comprehensive overview of polymer-complexed Ads, their progress, and future challenges in cancer treatment.

Advances and prospects of dynamic DNA nanostructures in biomedical applications

With the rapid development of DNA nanotechnology, the emergence of stimulus-responsive dynamic DNA nanostructures (DDNs) has broken many limitations of static DNA nanostructures, making precise, remote, and reversible control possible. DDNs are intelligent nanostructures with certain dynamic behaviors that are capable of responding to specific stimuli. The responsible stimuli of DDNs include exogenous metal ions, light, pH, etc., as well as endogenous small molecules such as GSH, ATP, etc. Due to the excellent stimulus responsiveness and other superior physiological characteristics of DDNs, they are now widely used in biomedical fields. For example, they can be applied in the fields of biosensing and bioimaging, which are able to detect biomarkers with greater spatial and temporal precision to help disease diagnosis and live cell physiological function studies. Moreover, they are excellent intelligent carriers for drug delivery in treating cancer and other diseases, achieving controlled release of drugs. And they can promote tissue regeneration and regulate cellular behaviors. Although some challenges need further study, such as the practical value in clinical applications, DDNs have shown great potential applications in the biomedical field.

With the rapid development of DNA nanotechnology, the emergence of stimulus-responsive dynamic DNA nanostructures (DDNs) has great potential applications in the biomedical field.

Honokiol-Based Nanomedicine Decorated with Ethylene Glycols Derivatives Promotes Antitumor Efficacy

Honokiol-loaded nanoparticles (HK-loaded NPs) exhibit potential antitumor activity; however, the factors affecting their antitumor efficacy are still unclear and need to be explored. This research was aimed to systematically estimate the influence of feed weight ratio (FWR) and nanocarrier structure on antitumor activity. Accordingly, three types of ethylene glycol derivatives, including linear poly(ethylene glycol) with molar mass of 2000 (PEG₄₅), first and second generation oligo(ethylene glycol) dendrons (G1 and G2) were used as nanocarriers, and a series of HK-loaded NPs with different FWR were prepared successfully using the evaporation-ultrasonication method. These NPs showed similar stability but demonstrated differences with respect to particle size, morphology, cumulative profile, and antitumor efficacy. The influence of the FWR was studied using G1 dendrons as nanocarriers; the results indicated that the particle size and morphology of G1 NPs were significantly affected, and G1 NPs (8/1), with the FWR of 8/1 for HK versus G1 dendron, exhibited the highest antitumor activity among all G1 NPs. Furthermore, the influence of nanocarrier structure was investigated at the FWR of 4/1; the findings revealed reduction in the particle diameter from 280 nm to 109 nm and change in morphology from sphere to flower-like structure with an increase in the branch degree from linear to dendron. Moreover, G2 NPs (4/1), with the FWR of 4/1 for HK versus G2 dendron, carrying the highest branch degree exhibited the greatest antitumor efficacy among all. These results are suggestive of influence of particle size and morphology on antitumor efficacy of HK-loaded NPs. Conclusively, this study demonstrated nanocarrier structure and the FWR significantly affect the antitumor efficacy of NPs, which should be optimized for designing nanoscale delivery systems.

Smart Nanoparticles for Chemo-Based Combinational Therapy

Cancer is a heterogeneous and complex disease. Traditional cancer therapy is associated with low therapeutic index, acquired resistance, and various adverse effects. With the increasing understanding of cancer biology and technology advancements, more strategies have been exploited to optimize the therapeutic outcomes. The rapid development and application of nanomedicine have motivated this progress. Combinational regimen, for instance, has become an indispensable approach for effective cancer treatment, including the combination of chemotherapeutic agents, chemo-energy, chemo-gene, chemo-small molecules, and chemo-immunology. Additionally, smart nanoplatforms that respond to external stimuli (such as light, temperature, ultrasound, and magnetic field), and/or to internal stimuli (such as changes in pH, enzymes, hypoxia, and redox) have been extensively investigated to improve precision therapy. Smart nanoplatforms for combinational therapy have demonstrated the potential to be the next generation cancer treatment regimen. This review aims to highlight the recent advances in smart combinational therapy.

Nanoparticle-mediated synergistic chemoimmunotherapy for tailoring cancer therapy: recent advances and perspectives

Nowadays, a potent challenge in cancer treatment is considered the lack of efficacious strategy, which has not been able to significantly reduce mortality. Chemoimmunotherapy (CIT) as a promising approach in both for the first-line and relapsed therapy demonstrated particular benefit from two key gating strategies, including chemotherapy and immunotherapy to cancer therapy; therefore, the discernment of their participation and role of potential synergies in CIT approach is determinant. In this study, in addition to balancing the pros and cons of CIT with the challenges of each of two main strategies, the recent advances in the cancer CIT have been discussed. Additionally, immunotherapeutic strategies and the immunomodulation effect induced by chemotherapy, which boosts CIT have been brought up. Finally, harnessing and development of the nanoparticles, which mediated CIT have expatiated in detail.

Near-infrared photothermal liposomal nanoantagonists for amplified cancer photodynamic therapy

Photodynamic therapy (PDT) has been demonstrated to be a promising strategy for the treatment of cancer, while its therapeutic efficacy is often compromised due to excessive concentrations of glutathione (GSH) as a reactive oxygen species (ROS) scavenger in cancer cells. Herein, we report the development of near-infrared (NIR) photothermal liposomal nanoantagonists (PLNAs) for amplified PDT through through the reduction of intracellular GSH biosynthesis. Such PLNAs were constructed via encapsulating a photosensitizer, indocyanine green (ICG) and a GSH synthesis antagonist, l-buthionine sulfoximine (BSO) into a thermal responsive liposome. Under NIR laser irradiation at 808 nm, PLNAs generate mild heat via a ICG-mediated photothermal conversion effect, which leads to the destruction of thermal responsive liposomes for a controlled release of BSO in a tumor microenvironment, ultimately reducing GSH levels. This amplifies intracellular oxidative stresses and thus synergizes with PDT to afford an enhanced therapeutic efficacy. Both in vitro and in vivo data verify that PLNA-mediated phototherapy has an at least 2-fold higher efficacy in killing cancer cells and inhibiting tumor growth compared to sole PDT. This study thus demonstrates a NIR photothermal drug delivery nanosystem for amplified photomedicine.

Intelligent stimuli-responsive nano immunomodulators for cancer immunotherapy

Cancer immunotherapy is a revolutionary treatment method in oncology, which uses a human's own immune system against cancer. Many immunomodulators that trigger an immune response have been developed and applied in cancer immunotherapy. However, there is the risk of causing an excessive immune response upon directly injecting common immunomodulators into the human body to trigger an immune response. Therefore, the development of intelligent stimuli-responsive immunomodulators to elicit controlled immune responses in cancer immunotherapy is of great significance. Nanotechnology offers the possibility of designing smart nanomedicine to amplify the antitumor response in a safe and effective manner. Progress relating to intelligent stimuli-responsive nano immunomodulators for cancer immunotherapy is highlighted as a new creative direction in the field. Considering the clinical demand for cancer immunotherapy, we put forward some suggestions for constructing new intelligent stimuli-responsive nano immunomodulators, which will advance the development of cancer immunotherapy.

Nanobiomaterial-based vaccination immunotherapy of cancer

Cancer immunotherapies including cancer vaccines, immune checkpoint blockade or chimeric antigen receptor T cells have been exploited as the attractive treatment modalities in recent years. Among these approaches, cancer vaccines that designed to deliver tumor antigens and adjuvants to activate the antigen presenting cells (APCs) and induce antitumor immune responses, have shown significant efficacy in inhibiting tumor growth, preventing tumor relapse and metastasis. Despite the potential of cancer vaccination strategies, the therapeutic outcomes in preclinical trials are failed to promote their clinical translation, which is in part due to their inefficient vaccination cascade of five critical steps: antigen identification, antigen encapsulation, antigen delivery, antigen release and antigen presentation to T cells. In recent years, it has been demonstrated that various nanobiomaterials hold great potential to enhance cancer vaccination cascade and improve their antitumor performance and reduce the off-target effect. We summarize the cutting-edge advances of nanobiomaterials-based vaccination immunotherapy of cancer in this review. The various cancer nanovaccines including antigen peptide/adjuvant-based nanovaccines, nucleic acid-based nanovaccines as well as biomimetic nanobiomaterials-based nanovaccines are discussed in detail. We also provide some challenges and perspectives associated with the clinical translation of cancer nanovaccines.

Cumulative Production of Bioactive Rg3, Rg5, Rk1, and CK from Fermented Black Ginseng Using Novel Aspergillus niger KHNT-1 Strain Isolated from Korean Traditional Food

Ginseng is an ancient herb widely consumed due to its healing property of active ginsenosides. Recent researchers were explored to increase its absorption and bioavailability of ginsenosides at the metabolic sites, due to its pharmacological activity. The purpose of this study was to investigate the isolation and characteristics of components obtained by a shorter steaming cycle (seven cycles) of white ginseng to fermented black ginseng, using a novel strain of Aspergillus niger KHNT-1 isolated from fermented soybean. The degree of bioactive of Rg3 increased effectively during the steaming process, and biotransformation converted the color towards black along active ginsenosides. Glycol moiety associated with C-3, C-6, or C-20 underwent rapid biotransformation and hydrolysis, such as Rb1, Rb2, Rc, Rd → Rg3, F2, and was converted to CK. Dehydration produces Rg3 → Rk1, Rg5. Rh2 → Rk2; thus, converted fermented black ginseng was solvent-extracted, and the isolated components were identified by TLC, HPLC, and quantification by LCMS. The unique composition obtained during this process with Rk1, Rg3, Rg5, and CK is nontoxic to HaCaT cell line up to 200 ug/mL for 24 h and was found to be effective in B16BL6 cell lines, in a dose- and time-dependent manner. Thus, it is a suitable candidate for nutraceuticals and cosmeceuticals.

Tumor immune microenvironment modulation-based drug delivery strategies for cancer immunotherapy

The past years have witnessed promising clinical feedback for anti-cancer immunotherapies, which have become one of the hot research topics; however, they are limited by poor delivery kinetics, narrow patient response profiles, and systemic side effects. To the best of our knowledge, the development of cancer is highly associated with the immune system, especially the tumor immune microenvironment (TIME). Based on the comprehensive understanding of the complexity and diversity of TIME, drug delivery strategies focused on the modulation of TIME can be of great significance for directing and improving cancer immunotherapy. This review highlights the TIME modulation in cancer immunotherapy and summarizes the versatile TIME modulation-based cancer immunotherapeutic strategies, medicative principles and accessory biotechniques for further clinical transformation. Remarkably, the recent advances of cancer immunotherapeutic drug delivery systems and future prospects of TIME modulation-based drug delivery systems for much more controlled and precise cancer immunotherapy will be emphatically discussed.

cRGD functionalized 2,1,3-benzothiadiazole (BTD)-containing two-photon absorbing red-emitter-conjugated amphiphilic poly(ethylene glycol)-block-poly(ε-caprolactone) for targeted bioimaging

A two-photon absorbing (2PA) red emitter group was chemically conjugated onto amphiphilic poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) copolymers, and further grafted with cyclo(Arg-Gly-Asp) (cRGD) peptide to form micelle 1. Micelle 1 with cRGD targeting groups were used for targeted bioimaging. For comparison, micelle 2 without the cRGD targeting groups were also prepared and investigated. The micelles were characterized using dynamic light scattering (DLS), showing average diameters of around 77 nm. The cRGD targeting group is known to bind specifically with α_vβ₃ integrin in cancer cells. In this study, α_vβ₃ integrin overexpressed human glioblastoma U87MG cell line and α_vβ₃ integrin deficient human cervical cancer HeLa cell line were chosen. Results showed that the cRGD targeting group enhanced the cellular uptake efficiency of the micelles significantly in α_vβ₃ integrin rich U87MG cells. Higher temperature (37 °C versus 4 °C) and calcium ions (with 3 M calcium chloride in the cell culture medium versus no addition of calcium ions) enhanced the cellular uptake efficiency, suggesting that the uptake of the micelles is through the endocytosis pathway in cells. A 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay was used to evaluate the cytotoxicity of the micelles and no significant cytotoxicity was observed. The BTD-containing two-photon absorbing emitter in the micelles showed a two-photon absorbing cross-section of 236 GM (1 GM = 1 × 10⁻⁵⁰ cm⁴ s per photonper molecule) at 820 nm, which is among the highest values reported for red 2PA emitters. Because of the two-photon absorbing characteristics, micelle 1 was successfully used for two-photon fluorescence imaging targeted to U87MG cells under a two-photon fluorescence microscope. This study is the first report regarding the targeted imaging of a specific cancer cell line (herein, U87MG) using the BTD-conjugated-fluorophore-containing block copolymers.

A two-photon absorbing (2PA) red emitter group was chemically conjugated onto amphiphilic poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) copolymers, and further grafted with cyclo(Arg-Gly-Asp) (cRGD) peptide to form micelle 1.

Smart injectable biogels based on hyaluronic acid bioconjugates finely substituted with poly(β-amino ester urethane) for cancer therapy

In situ-forming injectable biogels (IBGs) have been developed for the programmed delivery of potent chemotherapeutic drugs.