Enzyme-Induced Transformable Peptide Nanocarriers with Enhanced Drug Permeability and Retention to Improve Tumor Nanotherapy Efficacy

Geraniol and citral: recent developments in their anticancer credentials opening new vistas in complementary cancer therapy

About 10 million people are diagnosed with cancer each year. Globally, it is the second leading cause of death after heart disease, and by 2035, the death toll could reach 14.6 million. Several drugs and treatments are available to treat cancer, but survival rates remain low. Many studies in recent years have shown that plant-derived monoterpenes, particularly geraniol and citral, are effective against various cancers, including breast, liver, melanoma, endometrial, colon, prostate, and skin cancers. This trend has opened new possibilities for the development of new therapeutics or adjuvants in the field of cancer therapy. These monoterpenes can improve the efficacy of chemotherapy by modulating many signaling molecules and pathways within tumors. Analysis of reports on the anticancer effects published in the past 5 years provided an overview of the most important results of these and related properties. Also, the molecular mechanisms by which they exert their anticancer effects in cell and animal studies have been explained. Therefore, this review aims to highlight the scope of geraniol and citral as complementary or alternative treatment options in cancer therapy.

Intratumoral Microbiota as a Target for Advanced Cancer Therapeutics

In recent years, advancements in microbial sequencing technology have sparked an increasing interest in the bacteria residing within solid tumors and its distribution and functions in various tumors. Intratumoral bacteria critically modulate tumor oncogenesis and development through DNA damage induction, chronic inflammation, epigenetic alterations, and metabolic and immune regulation, while also influencing cancer treatment efficacy by affecting drug metabolism. In response to these discoveries, a variety of anti-cancer therapies targeting these microorganisms have emerged. These approaches encompass oncolytic therapy utilizing tumor-associated bacteria, the design of biomaterials based on intratumoral bacteria, the use of intratumoral bacterial components for drug delivery systems, and comprehensive strategies aimed at the eradication of tumor-promoting bacteria. Herein, this review article summarizes the distribution patterns of bacteria in different solid tumors, examines their impact on tumors, and evaluates current therapeutic strategies centered on tumor-associated bacteria. Furthermore, the challenges and prospects for developing drugs that target these bacterial communities are also explored, promising new directions for cancer treatment.

Precise Modulation of Pericyte Dysfunction by a Multifunctional Nanoprodrug to Ameliorate Alzheimer's Disease

Pericyte dysfunction severely undermines cerebrovascular integrity and exacerbates neurodegeneration in Alzheimer's disease (AD). However, pericyte-targeted therapy is a yet-untapped frontier for AD. Inspired by the elevation of vascular cell adhesion molecule-1 (VCAM-1) and reactive oxygen species (ROS) levels in pericyte lesions, we fabricated a multifunctional nanoprodrug by conjugating the hybrid peptide VLC, a fusion of the VCAM-1 high-affinity peptide VHS and the neuroprotective apolipoprotein mimetic peptide COG1410, to curcumin (Cur) through phenylboronic ester bond (VLC@Cur-NPs) to alleviate complex pericyte-related pathological changes. Importantly, VLC@Cur-NPs effectively homed to pericyte lesions via VLC and released their contents upon ROS stimulation to maximize their regulatory effects. Consequently, VLC@Cur-NPs markedly increased pericyte regeneration to form a positive feedback loop and thus improved neurovascular function and ultimately alleviated memory defects in APP/PS1 transgenic mice. We present a promising therapeutic strategy for AD that can precisely modulate pericytes and has the potential to treat other cerebrovascular diseases.

pH-responsive drug-loaded peptides enhance drug accumulation and promote apoptosis in tumor cells

The efficacy of chemotherapeutic drugs in tumor treatment is limited by their toxicity and side effects due to their inability to selectively accumulate in tumor tissue. In addition, chemotherapeutic agents are easily pumped out of tumor cells, resulting in their inadequate accumulation. To overcome these challenges, a drug delivery system utilizing the amphiphilic peptide Pep1 was designed. Pep1 can self-assemble into spherical nanoparticles (PL/Pep1) and encapsulate paclitaxel (PTX) and lapatinib (LAP). PL/Pep1 transformed into nanofibers in an acidic environment, resulting in longer drug retention and higher drug concentrations within tumor cells. Ultimately, PL/Pep1 inhibited tumor angiogenesis and enhanced tumor cell apoptosis. The use of shape-changing peptides as drug carriers to enhance cancer cell apoptosis is promising.

Advancements and prospects of lipid-based nanoparticles: dual frontiers in cancer treatment and vaccine development

Cancer is a complex heterogeneous disease that poses a significant public health challenge. In recent years, lipid-based nanoparticles (LBNPs) have expanded drug delivery and vaccine development options owing to their adaptable, non-toxic, tuneable physicochemical properties, versatile surface functionalisation, and biocompatibility. LBNPs are tiny artificial structures composed of lipid-like materials that can be engineered to encapsulate and deliver therapeutic agents with pinpoint accuracy. They have been widely explored in oncology; however, our understanding of their pharmacological mechanisms, effects of their composition, charge, and size on cellular uptake, tumour penetration, and how they can be utilised to develop cancer vaccines is still limited. Hence, we reviewed LBNPs' unique characteristics, biochemical features, and tumour-targeting mechanisms. Furthermore, we examined their ability to enhance cancer therapies and their potential contribution in developing anticancer vaccines. We critically analysed their advantages and challenges impeding swift advancements in oncology and highlighted promising avenues for future research.

Morphologically transformable peptide nanocarriers coloaded with doxorubicin and curcumin inhibit the growth and metastasis of hepatocellular carcinoma

In tumor treatment, the highly disordered vascular system and lack of accumulation of chemotherapeutic drugs in tumors severely limit the therapeutic role of nanocarriers. Smaller drug-containing nanoparticles (NPs) can better penetrate the tumor but are easily removed, which severely limits the tumor-killing properties of the drug. The chemotherapeutic medication doxorubicin (DOX) is highly toxic to the heart, but this toxicity can be effectively mitigated and the combined anticancer effect can be enhanced by clinically incorporating curcumin (CUR) as part of the dual therapy. We designed a small-molecule peptide, Pep1, containing a targeting peptide (CREKA) and a pH-responsive moiety. These NPs can target the blood vessels in tumor microthrombi and undergo a morphological shift in the tumor microenvironment. This process enhances the penetration and accumulation of drugs, ultimately improving the effectiveness of cancer treatment. In vitro and in vivo experiments demonstrated that this morphological transformation allowed rapid and effective drug release into tumors, the effective inhibition of tumor angiogenesis, and the promotion of tumor cell apoptosis, thus effectively killing tumor cells. Our findings provide a novel and simple approach to nhibit the growth and metastasis of hepatocellular carcinoma.

Advances in the variations and biomedical applications of stimuli-responsive nanodrug delivery systems

Chemotherapy is an important cancer treatment modality, but the clinical utility of chemotherapeutics is limited by their toxic side effects, inadequate distribution and insufficient intracellular concentrations. Nanodrug delivery systems (NDDSs) have shown significant advantages in cancer diagnosis and treatment. Variable NDDSs that respond to endogenous and exogenous triggers have attracted much research interest. Here, we summarized nanomaterials commonly used for tumor therapy, such as peptides, liposomes, and carbon nanotubes, as well as the responses of NDDSs to pH, enzymes, magnetic fields, light, and multiple stimuli. Specifically, well-designed NDDSs can change in size or morphology or rupture when induced by one or more stimuli. The varying responses of NDDSs to stimulation contribute to the molecular design and development of novel NDDSs, providing new ideas for improving drug penetration and accumulation, inhibiting tumor resistance and metastasis, and enhancing immunotherapy.

Enzyme-Induced Shape-Shifting Peptide Nanocarrier Coloaded with Paclitaxel and Dipyridamole Inhibits Platelet Function and Tumor Metastasis

Tumor-associated platelets can bind to tumor cells and protect circulating tumor cells from NK-mediated immune surveillance. Tumor-associated platelets secrete cytokines to induce the epithelial-mesenchymal transition (EMT) in tumor cells, which promotes tumor metastasis. Combining chemotherapeutic agents with antiplatelet drugs can reduce the occurrence of metastasis, but the systemic application of chemotherapeutic agents and antiplatelet drugs is prone to causing serious side effects. Therefore, delivering drugs to the tumor microthrombus site for long-lasting inhibition is a problem that needs to be addressed. Here, we show that small molecule peptide nanoparticles containing the Cys-Arg-Glu-Lys-Ala (CREKA) peptide can deliver the platelet inhibitor dipyridamole (DIP) and the chemotherapeutic drug paclitaxel (PTX) to tumor tissues, thereby inhibiting tumor-associated platelet function while killing tumor cells. The drug-loaded nanoparticles PD/Pep1 inhibited platelet-tumor cell interactions, were effectively taken up by tumor cells, and underwent morphological transformation induced by alkaline phosphatase (ALP) to prolong the retention time of the drugs. After intravenous injection, PD/Pep1 can target tumors and inhibit tumor metastasis. Thus, this small molecule peptide nanoformulation provides a simple strategy for efficient drug delivery and shows promise as a novel cancer therapy platform.

Chemo-immunotherapy by dual-enzyme responsive peptide self-assembling abolish melanoma

Herein, we designed Comp. 1 to simultaneously respond to two enzymes: alkaline phosphatase and matrix metalloproteinase 2, which is commonly found in highly malignant cancer cell lines containing B16-F10 murine melanoma cells and CT26 murine colon carcinoma cells. We used the regional differences in the expression levels of dual-markers to accurately release immune molecule IND into tumor microenvironment for the activation of anti-tumor related immune effects, while in-situ self-assembly occurs. The dual-enzyme response process can further regulate the peptide precursors' self-assembly in the form of short rod-shaped nanofibers, enabling the delivery of the loaded chemotherapeutic drug HCPT into the cancer cells and further allowing the peptide assemblies to escape from lysosomes and return to cytoplasm in the form of tiny nanoparticles to induce apoptosis of cancer cells. This process does not occur in the single-positive breast cancer cell line MCF-7 or the normal hepatocytes cell line LO2, indicating the selectivity of the cancer cells exhibited using our strategy. In vivo studies revealed that Comp. 1 can effectively cooperate with chemotherapy to enhance the immunotherapy effect and induce immune responses associated with elevated pro-inflammatory cytokines in vivo to inhibit malignant tumors growth. Our dual-enzyme responsive chemo-immunotherapy strategy feasible in anti-tumor treatment, provides a new avenue for regulating peptide self-assembly to adapt to diverse tumor properties and may eventually be used for the development of novel multifunctional anti-tumor nanomedicines.

Comparison of Tumor Non-specific and PD-L1 Specific Imaging by Near-Infrared Fluorescence/Cerenkov Luminescence Dual-Modality In-situ Imaging

Background

Labeled antibodies are excellent imaging agents in oncology to non-invasively visualize cancer-related antigens expression levels. However, tumor tracer uptake (TTU) of specific antibodies in-vivo may be inferior to non-specific IgG in some cases.

Objectives

To explore factors affecting labeled antibody visualization by PD-L1 specific and non-specific imaging of nude mouse tumors.

Methods

TTU was observed in RKO model on Cerenkov luminescence (CL) and near-infrared fluorescence (NIRF) imaging of radionuclide 131I or NIRF dyes labeled Atezolizumab and IgG. A mixture of NIRF dyes labeled Atezolizumab and 131I-labeled IgG was injected, and TTU was observed in the RKO and HCT8 model by NIRF/CL dual-modality in-situ imaging. TTU were observed by 131I-labeled Atezolizumab and IgG in-vitro distribution.

Results

Labeled IgG concentrated more in tumors than Atezolizumab. NIRF/CL imaging in 24 to 168 h showed that TTU gradually decreased over time, which decreased more slowly on CL imaging compared to NIRF imaging. The distribution data in-vitro showed that TTU of 131I-labeled IgG was higher than that of 131I-labeled Atezolizumab at any time point.

Conclusion

Non-specific IgG may not be suitable as a control for Atezolizumab in comparing tumor PD-L1 expression in nude mice via labeled antibody optical imaging under certain circumstances.

A dual drug-loaded peptide system with morphological transformation prolongs drug retention and inhibits breast cancer growth

The treatment of breast cancer relies heavily on chemotherapy, but chemotherapy is limited by the disadvantages of poor targeting, susceptibility to extracellular matrix (ECM) interference and a short duration of action in tumor cells. To address these limitations, we developed an amphipathic peptide containing an RGD motif, Pep1, that encapsulated paclitaxel (PTX) and losartan potassium (LP) to form the drug-loaded peptide PL/Pep1. PL/Pep1 self-assembled into spherical nanoparticles (NPs) under normal physiological conditions and transformed into aggregates containing short nanofibers at acidic pH. The RGD peptide facilitated tumor targeting and the aggregates prolonged drug retention in the tumor, which allowed more drug to reach and accumulate in the tumor tissue to promote apoptosis and remodel the tumor microenvironment. The results of in vitro and in vivo experiments confirmed the superiority of PL/Pep1 in terms of targeting, prolonged retention and facilitated penetration for antitumor therapy. In conclusion, amphipathic peptides as coloaded drug carriers are a new platform and strategy for breast cancer chemotherapy.

Dual stimuli-responsive mesoporous silica nanoparticles for efficient loading and smart delivery of doxorubicin to cancer with RGD-integrin targeting

The recent progress in nanoparticle applications, such as tumor-targeting, has enabled specific delivery of chemotherapeutics to malignant tissues with enhanced local efficacy while limiting side effects. However, existing delivery systems leave much room for improvement in terms of achieving enhanced colloidal stability in fluid medium, efficient targeting of intended sites, and effective release of therapeutic drugs into diseased cells. Here, an efficient stimuli-responsive nanocarrier for mammalian cells, termed RGD-NAMs, was developed, which enabled temperature- and pH-sensitive release of drug loads. The RGD-NAMs comprise two parts: a stimuli-responsive copolymer shell (NIBIm-AA-RGD) and drug-container core (MSNs). The RGD-NAMs have a stable drug-loading capacity with a marked difference in the release rate depending on the temperature and pH conditions. The RGD-NAMs also exhibit high colloidal stability in SBF (Stimulated body fluid) solutions and minimal toxicity in skeletal myoblasts (C2C12) and bovine arterial endothelial cells (BAEC). The doxorubicin-loaded RGD-NAMs induced a cytotoxic effect in a dose-dependent manner, which was furthered by an increase in temperature from 37 to 40 °C. Moreover, significant control of the release rate and the amount were achieved through pH change. This novel, smart drug-delivery system with high responsiveness to temperature and pH changes has wide application prospects in biomedical fields, including the theragnosis of tumors and vascular diseases.

Mesoporous silica nanoparticles with dual-targeting agricultural sources for enhanced cancer treatment via tritherapy

In this study, we introduced dual-targeting folic acid (FA) and hyaluronic acid (HA) modified on the surface of rice husk mesoporous silica nanoparticles (rMSNs). The rMSNs were employed as a drug delivery system loaded with camptothecin (CPT) as a model drug, Eu³⁺ ions as a photosensitizer for photodynamic therapy (PDT), bismuth (Bi) for photothermal therapy (PTT), and Gd³⁺ ions for magnetic resonance imaging (MRI) to develop novel nanoparticles, rMSN-EuGd-Bi@CPT-HA-FA, with dual-targeted function and triple therapy for cancer treatment. The results of the cell cytotoxicity experiment showed that the A549 cancer cells had a survival rate of approximately 35% when treated with 200 μg mL^-1 of rMSN-EuGd-Bi@CPT-HA-FA under 808 nm irradiation for 15 min. The dual-targeted function and synergistic treatment of CPT, PTT, and PDT were also responsible for the 20% survival rate of the A549 cancer cells treated with 200 μg mL^-1 of rMSN-EuGd-Bi@CPT-HA-FA under 808 nm irradiation for 30 min. The results showed that rMSN-EuGd-Bi@CPT-HA-FA can effectively combine chemotherapy (through CPT), PDT, and PTT for cancer treatment.

A multi-bioresponsive self-assembled nano drug delivery system based on hyaluronic acid and geraniol against liver cancer

Herein, a multi-bioresponsive self-assembled nano-drug delivery system (HSSG) was constructed by conjugating the anticancer drug Geraniol (GER) to hyaluronic acid (HA) via a disulfide bond. The HSSG NPs displayed a uniform spherical shape with an average diameter of ∼110 nm, maintained high stability, and realized controlled drug release in the tumor microenvironment (pH/glutathione/hyaluronidase). Results of fluorescence microscopy and flow cytometry verified that HSSG NPs were selectively uptaken by human hepatocellular carcinoma cell lines HepG2 and Huh7 via CD44 receptor-mediated internalization. Studies on H22 tumor-bearing mice demonstrate that HSSG NPs could effectively accumulate at the tumor site for a long period. In vitro and in vivo studies show that HSSG NPs significantly promoted the death of cancer cells while reducing the toxicity as compared to GER. Therefore, the HSSG NPs have great potential in the treatment of tumors.

Transformable nanodrugs for overcoming the biological barriers in the tumor environment during drug delivery

Drug delivery systems have been studied massively with explosive growth in the last few decades. However, challenges such as biological barriers are still obstructing the delivery efficiency of nanomedicines. Reports have shown that the physicochemical properties, such as the morphologies of nanodrugs, could highly affect their biodistribution and bioavailability. Therefore, transformable nanodrugs that take advantage of different sizes and shapes allow for overcoming multiple biological barriers, providing promising prospects for drug delivery. This review aims to present an overview of the most recent developments of transformable nanodrugs in this emerging field. First, the design principles and transformation mechanisms which serve as guidelines for smart nanodrugs are summarized. Afterward, their applications in overcoming biological barriers, including the bloodstream, intratumoral pressure, cellular membrane, endosomal wrapping, and nuclear membrane, are highlighted. Finally, discussions on the current developments and future perspectives of transformable nanodrugs are given.

Response of mesenchymal stem cells to surface topography of scaffolds and the underlying mechanisms

Mesenchymal stem/stromal cells (MSCs) serve as essential components of regenerative medicine. Their destiny is influenced by the interaction of the cells with the external environment. In addition to the biochemical cues in a microenvironment, physical cues of the topography of the surrounding materials such as the extracellular matrix emerge as a crucial regulator of stem cell destiny and function. With recent advances in technologies of materials production and surface modification, surfaces with micro/nanotopographical characteristics can be fabricated to mimic the micro/nanoscale mechanical stimuli of the extracellular matrix environment and regulate the biological behavior of cells. Understanding the interaction of cells with the topography of a surface is conducive to the control of stem cell fate for application in regenerative medicine. However, the mechanisms by which topography affects the biological behavior of stem cells have not been fully elucidated. This review will present the effects of surface topography at the nano/micrometer scale on stem cell adhesion, morphology, proliferation, migration, and differentiation. It also focuses on discussing current theories about the sensing and recognition of surface topology cues, the transduction of the extracellular cues into plasma, and the final activation of related signaling pathways and downstream gene expression in MSCs. These insights will provide a theoretical basis for the future design of biomaterial scaffolds for application in regenerative medicine and tissue engineering.

Recent progress in nanocarrier-based drug delivery systems for antitumour metastasis

Tumour metastasis is one of the major factors leading to poor prognosis as well as lower survival among cancer patients. A number of studies investigating the inhibition of tumour metastasis have been conducted. It is difficult to achieve satisfactory results with surgery alone for distant metastatic tumours, and chemotherapy can boost the healing rate and prognosis of patients. However, the poor therapeutic efficacy of chemotherapy drugs due to their low solubility, lack of tumour targeting, instability in vivo, high toxicity and multidrug resistance hinder their application. Immunotherapy is beneficial to the treatment of metastatic cancers, but it also has disadvantages such as adverse reactions and acquired resistance. Fortunately, delivery of chemotherapeutic drugs with nanocarriers can reduce systemic reactions caused by chemotherapeutic agents and inhibit metastasis. This review discusses the underlying mechanisms of metastasis, therapeutic approaches for antitumour metastasis, the advantages of nanodrug delivery systems and their application in reducing metastasis.

Antibacterial metal-phenolic nanosheets as smart carriers for the controlled release of epirubicin hydrochloride

Bacterial infections can cause serious complications in cancer treatment and have been proven to weaken therapeutic benefits. Recently, antibacterial nanomaterials that serve as carriers for anticancer drug delivery have been attracting extensive interest due to their combined antimicrobial and anticancer activities. In this study, antibacterial metal-phenolic nanosheets (Cu-TA) were successfully prepared via the self-assembly of the metal-phenolic coordination complexes formed between copper ions and tannic acid, and the structure, morphology, and formation mechanism of Cu-TA nanosheets were explored. The antibacterial activity of Cu-TA nanosheets against both Gram-positive and Gram-negative bacteria was detected using the minimum inhibitory concentration (MIC), zone of inhibition and plate counting methods. The MIC values of both bacterial strains were about 0.4 mg mL^-1, and the killing rates of Cu-TA samples were close to 100% at the concentration of 2 and 0.2 mg mL^-1 after 12-hour incubation. Epirubicin hydrochloride (EPI) molecules were successfully loaded on the porous Cu-TA nanosheets mainly through the formation of the Cu-EPI chelate complex and strong electrostatic interactions. The Cu-EPI complex and Cu-TA nanosheets could be disassembled under acidic conditions or in the presence of high levels of glutathione (GSH) after uptake by cancer cells, which triggered the unique pH and GSH-responsive controlled release behaviors of EPI and copper ions. The MTT assay results revealed that the presence of bacteria in Hep G2 cells can greatly impair the cell death rate induced by free EPI, but the resultant EPI-loaded Cu-TA nanosheets can significantly enhance cell death both in the presence and absence of bacteria.

Supramolecular Core-Shell Nanoassemblies with Tumor Microenvironment-Triggered Size and Structure Switch for Improved Photothermal Therapy

Photothermal therapy (PTT) is demonstrated to be an effective methodology for cancer treatment. However, the relatively low photothermal conversion efficiency, limited tumor accumulation, and penetration still remain to be challenging issues that hinder the clinical application of PTT. Herein, the core-shell hierarchical nanostructures induced by host-guest interaction between water-soluble pillar[5]arene (WP5) and polyethylene glycol-modified aniline tetramer (TAPEG) are constructed. The pH-responsive performance endows the core-shell nanostructures with size switchable property, with an average diameter of 200 nm in the neutral pH and 60 nm in the acidic microenvironment, which facilitates not only tumor accumulation but also tumor penetration. Moreover, the structure switch of WP5⊃TAPEG under acidic microenvironment and the dual mechanism regulated extending of п conjugate, inclusion in the hydrophobic cavity of WP5 and the dense distribution in the core-shell structured assemblies, dramatically enhance the absorption in the near-infrared-II region and, further, the photothermal conversion efficiency (60.2%). The as-designed intelligent nanoplatform is demonstrated for improved antitumor efficacy via PTT.