pH-Sensitive Biomimetic Nanosystem Based on Large-Pore Mesoporous Silica Nanoparticles with High Hyaluronidase Loading for Tumor Deep Penetration

Biomimetic nanosystems for pancreatic cancer therapy: A review

Pancreatic cancer (PC) is a highly lethal and aggressive malignancy, currently one of the leading causes of cancer-related deaths worldwide, in both women and men. PC is highly resistant to standard chemotherapy (CT) because its immunosuppressive and hypoxic tumor microenvironment and a dense desmoplastic stroma compartment extensively limit drug accessibility and perfusion. Although CT is one of the main therapeutic strategies for PC management contributing to tumor eradication through a cytotoxic effect, CT is associated with a poor pharmacokinetic profile and provokes deleterious systemic toxicity. This low efficacy-poor safety scenario urgently calls for innovative and highly specific therapeutic strategies to counteract this urgent clinical challenge. Nanotechnology-based precision materials for cancer may help improve drug stability and minimize the systemic cytotoxic effects by increasing drug tumor accumulation and also enabling controlled release, but several drawbacks still persist, such as the poor targeting efficiency. In the last few years increased attention has been paid to bioinspired nanosystems that can mimic either partially or totally biological systems, including lipid layers as suitable stealth coatings resembling the composition of cell membranes, lipoprotein- and blood protein-based nanosystems, and cell membrane-derived systems, such as extracellular vesicles, cell membrane nanovesicles and cell membrane-coated nanosystems, which display intrinsic cancer-targeting abilities, enhanced biocompatibility, decreased immunogenicity, and prolonged blood circulation profile. This review covers the recent breakthroughs on advanced biomimetic PC-targeted nanosystems, focusing on their design, properties and applications as innovative, multifunctional and versatile tools paving the way to improved PC diagnosis and treatment.

Extensive Review of Nanomedicine Strategies Targeting the Tumor Microenvironment in PDAC

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers in the world, mainly because of its powerful pro-connective tissue proliferation matrix and immunosuppressive tumor microenvironment (TME), which promote tumor progression and metastasis. In addition, the extracellular matrix leads to vascular collapse, increased interstitial fluid pressure, and obstruction of lymphatic return, thereby hindering effective drug delivery, deep penetration, and immune cell infiltration. Therefore, reshaping the TME to enhance tumor perfusion, increase deep drug penetration, and reverse immune suppression has become a key therapeutic strategy. Traditional therapies for PDAC, including surgery, radiation, and chemotherapy, face significant limitations. Surgery is challenging due to tumor location and growth, while chemotherapy and radiation are hindered by the dense extracellular matrix and immunosuppressive TME. In recent years, the advancement of nanotechnology has provided new opportunities to improve drug efficacy. Nanoscale drug delivery systems (NDDSs) provide several advantages, including improved drug stability in vivo, enhanced tumor penetration, and reduced systemic toxicity. However, the clinical translation of nanotechnology in PDAC therapy faces several challenges. These include the need for precise targeting and control over drug release, potential immune responses to the nanocarriers, and the scalability and cost-effectiveness of production. This article provides an overview of the latest nanobased methods for achieving better therapeutic outcomes and overcoming drug resistance. We pay special attention to TME-targeted therapy in the context of PDAC, discuss the advantages and limitations of current strategies, and emphasize promising new developments. By emphasizing the enormous potential of NDDSs in improving the treatment outcomes of patients with PDAC, while critically discussing the limitations of traditional therapies and the challenges faced by nanotechnology in achieving clinical breakthroughs, our review paves the way for future research in this rapidly developing field.

Optimization and mechanisms of proteolytic enzyme immobilization onto large-pore mesoporous silica nanoparticles: Enhanced tumor penetration

Immobilization of proteolytic enzymes onto nanocarriers is effective to improve drug diffusion in tumors through degrading the dense extracellular matrix (ECM). Herein, immobilization and release behaviors of hyaluronidase, bromelain, and collagenase (Coll) on mesoporous silica nanoparticles (MSNs) were explored. A series of cationic MSNs (CMSNs) with large and adjustable pore sizes were synthesized, and investigated together with two anionic MSNs of different pore sizes. CMSNs4.0 exhibited the highest enzyme loading capacity for hyaluronidase and bromelain, and CMSNs4.5 was the best for Coll. High electrostatic interaction, matched pore size, and large pore volume and surface area favor the immobilization. Changes of the enzyme conformations and surface charges with pH, existence of a space around the immobilized enzymes, and the depth of the pore structures, affect the release ratio and tunability. The optimal CMSNs-enzyme complexes exhibited deep and homogeneous penetration into pancreatic tumors, a tumor model with the densest ECM, with CMSNs4.5-Coll as the best. Upon loading with doxorubicin (DOX), the CMSNs-enzyme complexes induced high anti-tumor efficiencies. Conceivably, the DOX/CMSNs4.5-NH2-Coll nanodrug exhibited the most effective tumor therapy, with a tumor growth inhibition ratio of 86.1 %. The study provides excellent nanocarrier-enzyme complexes, and offers instructive theories for enhanced tumor penetration and therapy.

Size-Switchable Ru Nanoaggregates for Enhancing Phototherapy: Hyaluronidase-Triggered Disassembly to Alleviate Deep Tumor Hypoxia

Hypoxia is a critical factor for restricting photodynamic therapy (PDT) of tumor, and it becomes increasingly severe with increasing tissue depth. Thus, the relief of deep tumor hypoxia is extremely important to improve the PDT efficacy. Herein, tumor microenvironment (TME)-responsive size-switchable hyaluronic acid-hybridized Ru nanoaggregates (HA@Ru NAs) were developed via screening reaction temperature to alleviate deep tumor hypoxia for improving the tumor-specific PDT by the artful integration multiple bioactivated chemical reactions in situ and receptor-mediated targeting (RMT). In this nanosystem, Ru NPs not only enabled HA@Ru NAs to have near infrared (NIR)-mediated photothermal/photodynamic functions, but also could catalyze endogenous H2O2 to produce O2 in situ. More importantly, hyaluronidase (HAase) overexpressed in the TME could trigger disassembly of HA@Ru NAs via the hydrolysis of HA, offering the smart size switch capability from 60 to 15 nm for enhancing tumor penetration. Moreover, the RMT characteristics of HA ensured that HA@Ru NAs could specially enter CD44-overexpressed tumor cells, enhancing tumor-specific precision of phototherapy. Taken together these distinguishing characteristics, smart HA@Ru NAs successfully realized the relief of deep tumor hypoxia to improve the tumor-specific PDT.

Environmental stimulus-responsive mesoporous silica nanoparticles as anticancer drug delivery platforms

Currently, cancer poses a significant health challenge in the medical community. Traditional chemotherapeutic agents are often accompanied by toxic side effects and limited therapeutic efficacy, restricting their application and advancement in cancer treatment. Therefore, there is an urgent need for developing intelligent drug release systems. Mesoporous silica nanoparticles (MSNs) have many advantages, such as a large specific surface area, substantial pore volume and size, adjustable mesoporous material pore size, excellent biocompatibility, and thermodynamic stability, making them ideal carriers for drug delivery and release. Additionally, they have been widely used to develop novel anticancer drug carriers. Recently, MSNs have been employed to design responsive systems that react to the tumor microenvironment and external stimuli for controlled release of anticancer drugs. This includes factors within the intratumor environment, such as pH, temperature, enzymes, and glutathione as well as external tumor stimuli, such as light, magnetic field, and ultrasound, among others. In this review, we discuss the research progress on environmental stimulus-responsive MSNs in anticancer drug delivery systems, including internal and external environment single stimulus-responsive release and combined stimulus-responsive release. We also summarize the current challenges associated with environmental stimulus-responsive MSNs and elucidate future directions, providing a reference for the functionalization modification and practical application of these MSNs.