Ligand-Installed Nanocarriers toward Precision Therapy

Precise Subcellular Organelle Targeting for Boosting Endogenous-Stimuli-Mediated Tumor Therapy

Though numerous external-stimuli-triggered tumor therapies, including phototherapy, radiotherapy, and sonodynamic therapy have made great progress in cancer therapy, the low penetration depth of the laser, safety concerns of radiation, the therapeutic resistance, and the spatio-temporal constraints of the specific equipment restrict their convenient clinical applications. What is more, the inherent physiological barriers of the tumor microenvironment (TME), including hypoxia, heterogeneity, and high expression of antioxidant molecules also restrict the efficiency of tumor therapy. As a result, the development of nanoplatforms responsive to endogenous stimuli (such as glucose, acidic pH, cellular redox events, and etc.) has attracted great attention for starvation therapy, ion therapy, prodrug-mediated chemotherapy, or enzyme-catalyzed therapy. In addition, nanomedicines can be modified by some targeted units for precisely locating in subcellular organelles and boosting the destroying of tumor tissue, decreasing the dosage of nanoagents, reducing side effects, and enhancing the therapeutic efficiency. Herein, the properties of the TME, the advantages of endogenous stimuli, and the principles of subcellular-organelle-targeted strategies will be emphasized. Some necessary considerations for the exploitation of precision medicine and clinical translation of multifunctional nanomedicines in the future are also pointed out.

Nanoparticle designs for delivery of nucleic acid therapeutics as brain cancer therapies

Glioblastoma (GBM) is an aggressive central nervous system cancer with a dismal prognosis. The standard of care involves surgical resection followed by radiotherapy and chemotherapy, but five-year survival is only 5.6% despite these measures. Novel therapeutic approaches, such as immunotherapies, targeted therapies, and gene therapies, have been explored to attempt to extend survival for patients. Nanoparticles have been receiving increasing attention as promising vehicles for non-viral nucleic acid delivery in the context of GBM, though delivery is often limited by low blood-brain barrier permeability, particle instability, and low trafficking to target brain structures and cells. In this review, nanoparticle design considerations and new advances to overcome nucleic acid delivery challenges to treat brain cancer are summarized and discussed.

Mitochondria-Targeted Self-Assembly of Peptide-Based Nanomaterials

Mitochondria are well known to serve as the powerhouse for cells and also the initiator for some vital signaling pathways. A variety of diseases are discovered to be associated with the abnormalities of mitochondria, including cancers. Thus, targeting mitochondria and their metabolisms are recognized to be promising for cancer therapy. In recent years, great efforts have been devoted to developing mitochondria-targeted pharmaceuticals, including small molecular drugs, peptides, proteins, and genes, with several molecular drugs and peptides enrolled in clinical trials. Along with the advances of nanotechnology, self-assembled peptide-nanomaterials that integrate the biomarker-targeting, stimuli-response, self-assembly, and therapeutic effect, have been attracted increasing interest in the fields of biotechnology and nanomedicine. Particularly, in situ mitochondria-targeted self-assembling peptides that can assemble on the surface or inside mitochondria have opened another dimension for the mitochondria-targeted cancer therapy. Here, we highlight the recent progress of mitochondria-targeted peptide-nanomaterials, especially those in situ self-assembly systems in mitochondria, and their applications in cancer treatments.

A tyrosinase-responsive tumor-specific cascade amplification drug release system for melanoma therapy

Tumor-selective drug delivery could enhance anticancer efficacy and avoid drug side effects. However, because of tumor heterogeneity, current nanoparticle-based drug delivery systems rarely improve clinical outcomes significantly, commonly only reducing systemic toxicity. In this work, a new tumor-specific, tyrosinase-responsive cascade amplification release nanoparticle (TR-CARN) was developed to fulfill the needs for tumor-specific drug delivery and high efficacy cancer treatment. Tyrosinase (Tyr) is specifically expressed in melanomas and can catalyze acetaminophen (APAP) to increase reactive oxygen species (ROS). It was therefore utilized here to initiate the ROS amplification procedure. In TR-CARN, a ROS-responsive prodrug BDOX was loaded into an amphiphilic polymer, and APAP was linked to the polymer through a ROS-cleavable thioether bond. TR-CARN caused reduced side effects during the delivery because of the low toxicity of BDOX. Once TR-CARN entered into the tumor, endogenous ROS triggered initial APAP and BDOX release. Tyr-mediated ROS synthesis by APAP then accelerated APAP and BDOX release and toxification. Consequently, TR-CARN achieved melanoma-specific treatment of high efficacy through the cascade amplification strategy with enhanced biosafety.

Conjugation of glucosylated polymer chains to checkpoint blockade antibodies augments their efficacy and specificity for glioblastoma

Because of the blood-tumour barrier and cross-reactivity with healthy tissues, immune checkpoint blockade therapy against glioblastoma has inadequate efficacy and is associated with a high risk of immune-related adverse events. Here we show that anti-programmed death-ligand 1 antibodies conjugated with multiple poly(ethylene glycol) (PEG) chains functionalized to target glucose transporter 1 (which is overexpressed in brain capillaries) and detaching in the reductive tumour microenvironment augment the potency and safety of checkpoint blockade therapy against glioblastoma. In mice bearing orthotopic glioblastoma tumours, a single dose of glucosylated and multi-PEGylated antibodies reinvigorated antitumour immune responses, induced immunological memory that protected the animals against rechallenge with tumour cells, and suppressed autoimmune responses in the animals' healthy tissues. Drug-delivery formulations leveraging multivalent ligand interactions and the properties of the tumour microenvironment to facilitate the crossing of blood-tumour barriers and increase drug specificity may enhance the efficacy and safety of other antibody-based therapies.

Genetically Engineered Cellular Membrane Vesicles as Tailorable Shells for Therapeutics

Benefiting from the blooming interaction of nanotechnology and biotechnology, biosynthetic cellular membrane vesicles (Bio-MVs) have shown superior characteristics for therapeutic transportation because of their hydrophilic cavity and hydrophobic bilayer structure, as well as their inherent biocompatibility and negligible immunogenicity. These excellent cell-like features with specific functional protein expression on the surface can invoke their remarkable ability for Bio-MVs based recombinant protein therapy to facilitate the advanced synergy in poly-therapy. To date, various tactics have been developed for Bio-MVs surface modification with functional proteins through hydrophobic insertion or multivalent electrostatic interactions. While the Bio-MVs grow through genetically engineering strategies can maintain binding specificity, sort orders, and lead to strict information about artificial proteins in a facile and sustainable way. In this progress report, the most current technology of Bio-MVs is discussed, with an emphasis on their multi-functionalities as "tailorable shells" for delivering bio-functional moieties and therapeutic entities. The most notable success and challenges via genetically engineered tactics to achieve the new generation of Bio-MVs are highlighted. Besides, future perspectives of Bio-MVs in novel bio-nanotherapy are provided.

Cation-Free siRNA Micelles as Effective Drug Delivery Platform and Potent RNAi Nanomedicines for Glioblastoma Therapy

Nanoparticle-based small interfering RNA (siRNA) therapy shows great promise for glioblastoma (GBM). However, charge associated toxicity and limited blood-brain-barrier (BBB) penetration remain significant challenges for siRNA delivery for GBM therapy. Herein, novel cation-free siRNA micelles, prepared by the self-assembly of siRNA-disulfide-poly(N-isopropylacrylamide) (siRNA-SS-PNIPAM) diblock copolymers, are prepared. The siRNA micelles not only display enhanced blood circulation time, superior cell take-up, and effective at-site siRNA release, but also achieve potent BBB penetration. Moreover, due to being non-cationic, these siRNA micelles exert no charge-associated toxicity. Notably, these desirable properties of this novel RNA interfering (RNAi) nanomedicine result in outstanding growth inhibition of orthotopic U87MG xenografts without causing adverse effects, achieving remarkably improved survival benefits. Moreover, as a novel type of polymeric micelle, the siRNA micelle displays effective drug loading ability. When utilizing temozolomide (TMZ) as a model loading drug, the siRNA micelle realizes effective synergistic therapy effect via targeting the key gene (signal transducers and activators of transcription 3, STAT3) in TMZ drug resistant pathways. The authors' results show that this siRNA micelle nanoparticle can serve as a robust and versatile drug codelivery platform, and RNAi nanomedicine and for effective GBM treatment.

Do Lipid-based Nanoparticles Hold Promise for Advancing the Clinical Translation of Anticancer Alkaloids?

Since the commercialization of morphine in 1826, numerous alkaloids have been isolated and exploited effectively for the betterment of mankind, including cancer treatment. However, the commercialization of alkaloids as anticancer agents has generally been limited by serious side effects due to their lack of specificity to cancer cells, indiscriminate tissue distribution and toxic formulation excipients. Lipid-based nanoparticles represent the most effective drug delivery system concerning clinical translation owing to their unique, appealing characteristics for drug delivery. To the extent of our knowledge, this is the first review to compile in vitro and in vivo evidence of encapsulating anticancer alkaloids in lipid-based nanoparticles. Alkaloids encapsulated in lipid-based nanoparticles have generally displayed enhanced in vitro cytotoxicity and an improved in vivo efficacy and toxicity profile than free alkaloids in various cancers. Encapsulated alkaloids also demonstrated the ability to overcome multidrug resistance in vitro and in vivo. These findings support the broad application of lipid-based nanoparticles to encapsulate anticancer alkaloids and facilitate their clinical translation. The review then discusses several limitations of the studies analyzed, particularly the discrepancies in reporting the pharmacokinetics, biodistribution and toxicity data. Finally, we conclude with examples of clinically successful encapsulated alkaloids that have received regulatory approval and are undergoing clinical evaluation.

Recent advances in polymeric core-shell nanocarriers for targeted delivery of chemotherapeutic drugs

The treatment effect of chemotherapeutics is often impeded by nonspecific biodistribution and limited biocompatibility. Polymeric core-shell nanocarriers (PCS NCs) composed of a polymer core and at least one shell have been widely applied for cancer therapy and have shown great potential in selectively delivering chemotherapeutic drugs to tumor sites. These PCS NCs can effectively ameliorate the delivery efficiency and therapeutic index of anticarcinogens by prolonging drug residence in the bloodstream, enhancing tumor tissue drug penetration, facilitating cellular drug uptake, controlling the spatiotemporal release of payloads, or codelivering two or more bioactive agents. This review summarizes recently published literature on using PCS NCs to transport chemotherapeutic drugs with poor aqueous solubility and discusses their design principles, structural features, functional properties, and potential limitations.

Targeted delivery and stimulus-responsive release of anticancer drugs for efficient chemotherapy

Chemotherapy is currently an irreplaceable strategy for cancer treatment. Doxorubicin hydrochloride (DOX) is a clinical first-line drug for cancer chemotherapy. While its efficacy for cancer treatment is greatly compromised due to invalid enrichment or serious side effects. To increase the content of intracellular targets and boost the antitumor effect of DOX, a novel biotinylated hyaluronic acid-guided dual-functionalized CaCO₃-based drug delivery system (DOX@BHNP) with target specificity and acid-triggered drug-releasing capability was synthesized. The ability of the drug delivery system on enriching DOX in mitochondria and nucleus, which further cause significant tumor inhibition, were investigated to provide a more comprehensive understanding of this CaCO₃-based drug delivery system. After targeted endocytosis by tumor cells, DOX could release faster in the weakly acidic lysosome, and further enrich in mitochondria and nucleus, which cause mitochondrial destruction and nuclear DNA leakage, and result in cell cycle arrest and cell apoptosis. Virtually, an effective tumor inhibition was observed in vitro and in vivo. More importantly, the batch-to-batch variation of DOX loading level in the DOX@BHNP system is negligible, and no obvious histological changes in the main organs were observed, indicating the promising application of this functionalized drug delivery system in cancer treatment.

Tuning the Elasticity of Polymersomes for Brain Tumor Targeting

Nanoformulations show great potential for delivering drugs to treat brain tumors. However, how the mechanical properties of nanoformulations affect their ultimate brain destination is still unknown. Here, a library of membrane-crosslinked polymersomes with different elasticity are synthesized to investigate their ability to effectively target brain tumors. Crosslinked polymersomes with identical particle size, zeta potential and shape are assessed, but their elasticity is varied depending on the rigidity of incorporated crosslinkers. Benzyl and oxyethylene containing crosslinkers demonstrate higher and lower Young's modulus, respectively. Interestingly, stiff polymersomes exert superior brain tumor cell uptake, excellent in vitro blood brain barrier (BBB) and tumor penetration but relatively shorter blood circulation time than their soft counterparts. These results together affect the in vivo performance for which rigid polymersomes exerting higher brain tumor accumulation in an orthotopic glioblastoma (GBM) tumor model. The results demonstrate the crucial role of nanoformulation elasticity for brain-tumor targeting and will be useful for the design of future brain targeting drug delivery systems for the treatment of brain disease.

Boronic Acid Ligands Can Target Multiple Subpopulations of Pancreatic Cancer Stem Cells via pH-Dependent Glycan-Terminal Sialic Acid Recognition

Eradication of cancer stem cells (CSCs) is an ultimate goal in cancer chemotherapy. Although a ligand-assisted targeting approach seems rational, the existence of subpopulations of CSCs and their discrimination from those present on healthy sites makes it a severe challenge. Some boronic acid (BA) derivatives are known for the ability to bind with glycan-terminal sialic acid (SA), in a manner dependent on the acidification found in hypoxic tumoral microenvironment. Taking advantage of this feature, here we show that the BA-ligand fluorescence conjugate can effectively target multiple CSC subpopulations in parallel, which otherwise must be independently aimed when using antibody--ligands.

Recent Progress in Phthalocyanine-Polymeric Nanoparticle Delivery Systems for Cancer Photodynamic Therapy

This perspective article summarizes the last decade’s developments in the field of phthalocyanine (Pc)-polymeric nanoparticle (NP) delivery systems for cancer photodynamic therapy (PDT), including studies with at least in vitro data. Moreover, special attention will be paid to the various strategies for enhancing the behavior of Pc-polymeric NPs in PDT, underlining the great potential of this class of nanomaterials as advanced Pcs’ nanocarriers for cancer PDT. This review shows that there is still a lot of research to be done, opening the door to new and interesting nanodelivery systems.

Poly(l-glutamic acid)-cisplatin nanoformulations with detachable PEGylation for prolonged circulation half-life and enhanced cell internalization

PEGylation has been widely applied to prolong the circulation times of nanomedicines via the steric shielding effect, which consequently improves the intratumoral accumulation. However, cell uptake of PEGylated nanoformulations is always blocked by the steric repulsion of PEG, which limits their therapeutic effect. To this end, we designed and prepared two kinds of poly(l-glutamic acid)-cisplatin (PLG-CDDP) nanoformulations with detachable PEG, which is responsive to specific tumor tissue microenvironments for prolonged circulation time and enhanced cell internalization. The extracellular pH (pHe)-responsive cleavage 2-propionic-3-methylmaleic anhydride (CDM)-derived amide bond and matrix metalloproteinases-2/9 (MMP-2/9)-sensitive degradable peptide PLGLAG were utilized to link PLG and PEG, yielding pHe-responsive PEG-pH e-PLG and MMP-sensitive PEG-MMP-PLG. The corresponding smart nanoformulations PEG-pH e-PLG-Pt and PEG-MMP-PLG-Pt were then prepared by the complexation of polypeptides and cisplatin (CDDP). The circulation half-lives of PEG-pH e-PLG-Pt and PEG-MMP-PLG-Pt were about 4.6 and 4.2 times higher than that of the control PLG-Pt, respectively. Upon reaching tumor tissue, PEG on the surface of nanomedicines was detached as triggered by pHe or MMP, which increased intratumoral CDDP retention, enhanced cell uptake, and improved antitumor efficacy toward a fatal high-grade serous ovarian cancer (HGSOC) mouse model, indicating the promising prospects for clinical application of detachable PEGylated nanoformulations.

Engineering Nanorobots for Tumor-Targeting Drug Delivery: From Dynamic Control to Stimuli-Responsive Strategy

Nanotechnology has been widely applied to the fabrication of drug delivery systems in the past decades. Recently, with the progress made in microfabrication approaches, nanorobots are steadily becoming a promising means for tumor-targeting drug delivery. In general, nanorobots can be divided into two categories: nanomotors and stimuli-responsive nanorobots. Nanomotors are nanoscale systems with the ability to convert surrounding energies into mechanical motion, whereas stimuli-responsive nanorobots are featured with activatable capacity in response to various endogenous and exogenous stimulations. In this minireview, the dynamic control of nanomotors and the rational design of stimuli-responsive nanorobots are overviewed, with particular emphasis on their contribution to tumor-targeting therapy. Moreover, challenges and perspectives associated with the future development of nanorobots are presented.

Phosphorylcholine-Installed Nanocarriers Target Pancreatic Cancer Cells through the Phospholipid Transfer Protein

Phosphorylcholine (PC) has been used to improve the water solubility and biocompatibility of biomaterials. Here, we show that PC can also work as a ligand for targeting cancer cells based on their increased phospholipid metabolism. PC-installed multiarm poly(ethylene glycol)s and polymeric micelles achieved high and rapid internalization in pancreatic cancer cells. This enhanced cellular uptake was drastically reduced when the cells were incubated with excess free PC or at 4 °C, as well as by inhibiting the phospholipid transfer protein (PLTP) on the surface of cancer cells, indicating an energy dependent active transport mediated by PLTP.

Beyond DNA-targeting in Cancer Chemotherapy. Emerging Frontiers - A Review

Modern anti-cancer drugs target DNA specifically for rapid division of malignant cells. One downside of this approach is that they also target other rapidly dividing healthy cells, such as those involved in hair growth leading to serious toxic side effects and hair loss. Therefore, it would be better to develop novel agents that address cellular signaling mechanisms unique to cancerous cells, and new research is now focussing on such approaches. Although the classical chemotherapy area involving DNA as the set target continues to produce important findings, nevertheless, a distinctly discernible emerging trend is the divergence from the cisplatin operation model that uses the metal as the primary active center of the drug. Many successful anti-cancer drugs present are associated with elevated toxicity levels. Cancers also develop immunity against most therapies and the area of cancer research can, therefore, be seen as an area with a high unaddressed need. Hence, ongoing work into cancer pathogenesis is important to create accurate preclinical tests that can contribute to the development of innovative drugs to manage and treat cancer. Some of the emergent frontiers utilizing different approaches include nanoparticles delivery, use of quantum dots, metal complexes, tumor ablation, magnetic hypothermia and hyperthermia by use of Superparamagnetic Iron oxide Nanostructures, pathomics and radiomics, laser surgery and exosomes. This review summarizes these new approaches in good detail, giving critical views with necessary comparisons. It also delves into what they carry for the future, including their advantages and disadvantages.

Kolios M, Bai W, Hu B, Wang W, Zheng Y. Marriage of Virus-Mimic Surface Topology and Microbubble-Assisted Ultrasound for Enhanced Intratumor Accumulation and Improved Cancer Theranostics

The low delivery efficiency of nanoparticles to solid tumors greatly reduces the therapeutic efficacy and safety which is closely related to low permeability and poor distribution at tumor sites. In this work, an "intrinsic plus extrinsic superiority" administration strategy is proposed to dramatically enhance the mean delivery efficiency of nanoparticles in prostate cancer to 6.84% of injected dose, compared to 1.42% as the maximum in prostate cancer in the previously reported study. Specifically, the intrinsic superiority refers to the virus-mimic surface topology of the nanoparticles for enhanced nano-bio interactions. Meanwhile, the extrinsic stimuli of microbubble-assisted low-frequency ultrasound is to enhance permeability of biological barriers and improve intratumor distribution. The enhanced intratumor enrichment can be verified by photoacoustic resonance imaging, fluorescence imaging, and magnetic resonance imaging in this multifunctional nanoplatform, which also facilitates excellent anticancer effect of photothermal treatment, photodynamic treatment, and sonodynamic treatment via combined laser and ultrasound irradiation. This study confirms the significant advance in nanoparticle accumulation in multiple tumor models, which provides an innovative delivery paradigm to improve intratumor accumulation of nanotherapeutics.

Stimuli-Responsive Polymeric Nanoplatforms for Cancer Therapy

Polymeric nanoparticles have been widely used as carriers of drugs and bioimaging agents due to their excellent biocompatibility, biodegradability, and structural versatility. The principal application of polymeric nanoparticles in medicine is for cancer therapy, with increased tumor accumulation, precision delivery of anticancer drugs to target sites, higher solubility of pharmaceutical properties and lower systemic toxicity. Recently, the stimuli-responsive polymeric nanoplatforms attracted more and more attention because they can change their physicochemical properties responding to the stimuli conditions, such as low pH, enzyme, redox agents, hypoxia, light, temperature, magnetic field, ultrasound, and so on. Moreover, the unique properties of stimuli-responsive polymeric nanocarriers in target tissues may significantly improve the bioactivity of delivered agents for cancer treatment. This review introduces stimuli-responsive polymeric nanoparticles and their applications in tumor theranostics with the loading of chemical drugs, nucleic drugs and imaging molecules. In addition, we discuss the strategy for designing multifunctional polymeric nanocarriers and provide the perspective for the clinical applications of these stimuli-responsive polymeric nanoplatforms.

Effect of Protein Corona on Mitochondrial Targeting Ability and Cytotoxicity of Triphenylphosphonium Conjugated with Polyglycerol-Functionalized Nanodiamond

Functionalization of nanoparticles (NPs) with targeting moieties has a high potential to advance precision nanomedicine. However, the targeting moieties on a NP surface are known to be masked by a protein corona in biofluids, lowering the targeting efficiency. Although it has been demonstrated at the cellular level, little is known about the influence of the protein corona on the subcellular targeting. Herein, we adopted triphenylphosphonium (TPP) as a mitochondrial targeting moiety and investigated the effects of protein coronas from fetal bovine serum and human plasma on its targeting ability and cytotoxicity. Specifically, we introduced TPP in low (l) and high (h) densities on the surface of nanodiamond (ND) functionalized with polyglycerol (PG). Despite the "corona-free" PG interface, we found that the TPP moiety attracted proteins to form a corona layer with clear linearity between the TPP density and the protein amount. By performing investigations on human cervix epithelium (HeLa) and human lung epithelial carcinoma (A549) cells, we further demonstrated that (1) the protein corona alleviated the cytotoxicity of both ND-PG-TPP-l and -h, (2) a smaller amount of proteins on the surface of ND-PG-TPP-l did not affect its mitochondrial targeting ability, and (3) a larger amount of proteins on the surface of ND-PG-TPP-h diminished its targeting specificity by restricting the NDs inside the endosome and lysosome compartments. Our findings will provide in-depth insights into the design of NPs with active targeting moiety for more precise and safer delivery at the subcellular level.

Targeted Micellar Phthalocyanine for Lymph Node Metastasis Homing and Photothermal Therapy in an Orthotopic Colorectal Tumor Model

Small-sized trastuzumab-targeted micelles (T-MP) were engineered using a surfactant-stripping approach that yielded concentrated phthalocyanines with strong near infrared absorption. T-MP accumulated more in the lymph node (LN) metastases of orthotopic colorectal cancer compared to the micelles conjugated with control IgG. Following surgical resection of the primary tumor, minimally invasive photothermal treatment of the metastatic LN with T-MP, but not the control micelles, extended mouse survival.

ABSTRACT

Tumor lymph node (LN) metastasis seriously affects the treatment prognosis. Studies have shown that nanoparticles with size of sub-50 nm can directly penetrate into LN metastases after intravenous administration. Here, we speculate through introducing targeting capacity, the nanoparticle accumulation in LN metastases would be further enhanced for improved local treatment such as photothermal therapy. Trastuzumab-targeted micelles (< 50 nm) were formulated using a unique surfactant-stripping approach that yielded concentrated phthalocyanines with strong near-infrared absorption. Targeted micellar phthalocyanine (T-MP) was an effective photothermal transducer and ablated HT-29 cells in vitro. A HER2-expressing colorectal cancer cell line (HT-29) was used to establish an orthotopic mouse model that developed metastatic disease in mesenteric sentinel LN. T-MP accumulated more in the LN metastases compared to the micelles conjugated with control IgG. Following surgical resection of the primary tumor, minimally invasive photothermal treatment of the metastatic LN with T-MP, but not the control micelles, extended mouse survival. Our findings demonstrate for the first time that targeted small-sized nanoparticles have potential to enable superior paradigms for dealing with LN metastases. [Image: see text]

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40820-021-00666-8.

Remodeling tumor microenvironment with nanomedicines

The tumor microenvironment (TME) has been recognized as a major contributor to cancer malignancy and therapeutic resistance. Thus, strategies directed to re-engineer the TME are emerging as promising approaches for improving the efficacy of antitumor therapies by enhancing tumor perfusion and drug delivery, as well as alleviating the immunosuppressive TME. In this regard, nanomedicine has shown great potential for developing effective treatments capable of re-modeling the TME by controlling drug action in a spatiotemporal manner and allowing long-lasting modulatory effects on the TME. Herein, we review recent progress on TME re-engineering by using nanomedicine, particularly focusing on formulations controlling TME characteristics through targeted interaction with cellular components of the TME. Importantly, the TME should be re-engineering to a quiescent phenotype rather than be destroyed. Finally, immediate challenges and future perspectives of TME-re-engineering nanomedicines are discussed, anticipating further innovation in this growing field. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Development of Toll-like Receptor Agonist-Loaded Nanoparticles as Precision Immunotherapy for Reprogramming Tumor-Associated Macrophages

Most cancers contain abundant tumor-associated macrophages (TAMs). TAMs usually display a tumor-supportive M2-like phenotype; they promote tumor growth and influence lymphocyte infiltration, leading to immunosuppression. These properties have made TAMs an attractive cancer immunotherapy target. One promising immunotherapeutic strategy involves switching the tumor-promoting immune suppressive microenvironment by reprogramming TAMs. However, clinical trials of M2-like macrophage reprogramming have yielded unsatisfactory results due to their low efficacy and nonselective effects. In this article, we describe the development of M2-like macrophage-targeting nanoparticles (PNP@R@M-T) that efficiently and selectively deliver drugs to 58% of M2-like macrophages, over 39% of M1-like macrophages, and 32% of dendritic cells within 24 h in vivo. Compared with the control groups, administration of PNP@R@M-T dramatically reprogrammed the M2-like macrophages (51%), reduced tumor size (82%), and prolonged survival. Our findings indicate that PNP@R@M-T nanoparticles provide an effective and selective reprogramming strategy for macrophage-mediated cancer immunotherapy.

Recent Progress on Immunotherapy for Breast Cancer: Tumor Microenvironment, Nanotechnology and More

Immunotherapy is a major emerging treatment for breast cancer (BC). However, not all breast cancer patients derive benefit from immunotherapy. Predictive biomarkers of immunotherapy, such as tumor mutation burden and tumor-infiltrating lymphocytes, are promising to stratify the patients with BC and optimize the therapeutic effect. Various targets of the immune response pathway have also been explored to expand the modalities of immunotherapy. The use of nanotechnology for the imaging of predictive biomarkers and the combination with other therapeutic modalities presents a number of advantages for the immunotherapy of BC. In this review, we summary the emerging therapeutic modalities of immunotherapy, present prominent examples of immunotherapy in BC, and discuss the future opportunity of nanotechnology in the immunotherapy of BC.

Cancer-Cell-Activated in situ Synthesis of Mitochondria-Targeting AIE Photosensitizer for Precise Photodynamic Therapy

Maximization of phototoxic damage on tumor with minimized side effect on normal tissue is essential for effective anticancer photodynamic therapy (PDT). This requires highly cancer-cell-specific or even cancer-cell-organelle-specific synthesis or delivery of efficient photosensitizers (PSs) in vitro and in vivo, which is difficult to achieve. Herein, we report a strategy of cancer-cell-activated PS synthesis, by which an efficient mitochondria-targeting photosensitizer with aggregation-induced-emission (AIE) feature can be selectively synthesized as an efficient image-guided PDT agent inside cancer cells. MOF-199, a Cu^II -based metal-organic framework, was selected as an inert carrier to load the PS precursors for efficient delivery and served as a Cu^I catalyst source for in situ click reaction to form PSs exclusively in cancer cells. The in situ synthesized PS showed mitochondria-targeting capability, allowing potent cancer-cell-specific ablation under light irradiation. The high specificity of PSs produced in cancer cells also makes it safer post-treatment.

Polymeric RNAi Constructs Tailored with Appreciable Transcellular Trafficking Functions for Potential Suppression of Parathyroid Hormone Production

Polymeric small interfering RNA (siRNA) conjugate was elaborated to sequentially circumvent the predefined biological barriers encountered in the journey of transcellular delivery of siRNA into cytosol. Herein, classic ring-opening polymerization was employed for synthesis of well-defined poly(amino acid) derivatives possessing an array of carboxyl groups in an attempt to resemble the structural characteristics of hyaluronan. Furthermore, the hyaluronan-like synthetic was conjugated with a multiple of siRNA through a glutathione (GSH)-responsive disulfide linkage. The siRNA conjugate appeared to utilize the hyaluronan-specific receptors of CD44 for cell internalization, indicating similar functionalities to our hyaluronan-mimicking synthetic. Furthermore, the carboxyl groups of hyaluronan-like synthetics were designed to be selectively detached in subcellular acidic endosomes/lysosomes and transform into the cytomembrane-disruptive flanking ethylenediamine moieties, which appeared to be crucial in facilitating translocation of siRNA payloads from entrapment and degradation in lysosomes toward the cytosol. Eventually, active siRNA could be smoothly released from the synthetic due to the GSH cleavage disulfide linkage (disulfide), consequently accounting for potent RNA knockdown activities (>90%) toward cancerous cells. In addition, appreciable knockdown of parathyroid hormone was also achieved from our proposed siRNA conjugates in parathyroid cells. Hence, the elaborated siRNA conjugate showed tremendous potential in treatment of hyperparathyroidism, and could be developed further for systemic RNA interference (RNAi) therapeutics. Moreover, this study could also be the first example of a synthetic mimic to hyaluronan acquiring its functionalities, which could have important implications for further development of biomimic materials in pursuit of biomedical applications.

Multifunctional polymeric micellar nanomedicine in the diagnosis and treatment of cancer

Polymeric micelles are a prevalent topic of research for the past decade, especially concerning their fitting ability to deliver drug and diagnostic agents. This delivery system offers outstanding advantages, such as biocompatibility, high loading efficiency, water-solubility, and good stability in biological fluids, to name a few. The multifunctional polymeric micellar architect offers the added capability to adapt its surface to meet the looked-for clinical needs. This review cross-talks the recent reports, proof-of-concept studies, patents, and clinical trials that utilize polymeric micellar family architectures concerning cancer targeted delivery of anticancer drugs, gene therapeutics, and diagnostic agents. The manuscript also expounds on the underlying opportunities, allied challenges, and ways to resolve their bench-to-bedside translation for allied clinical applications.

Highway to Success—Developing Advanced Polymer Therapeutics

Polymer therapeutics are advancing as an important class of drugs. Polymers have already demonstrated their value in extending the half‐life of proteins. They show great potential as delivery systems for improving the therapeutic index of drugs, via biophysical targeting and more recently with more precision targeting. They are also important for intracellular delivery of nucleic acid based drugs. The same frameworks that have been successfully applied to improve the small molecule drug development can be adopted. This approach together with improved pathophysiological disease knowledge and critical developability considerations, imperative given the size and complexity of polymer therapeutics, provides a structured framework that should improve their clinical translation and exploit their functionality and potential. Progress in understanding the right target, gaining the right tissue and cell exposure, ensuring the right safety, selecting the right patient population is discussed. The right commercial considerations are outlined and the need for a multi‐disciplinary approach is emphasized. Crucial developability factors together with scientific and technical advancements to enable pharmaceutical development of a quality robust product are addressed. It is argued that by applying this structured approach to their design and development, polymer therapeutics will continue to grow and develop as important next generation medicines.

AS1411-functionalized delivery nanosystems for targeted cancer therapy

Nucleolin (NCL) is a multifunctional nucleolar phosphoprotein harboring critical roles in cells such as cell proliferation, survival, and growth. The dysregulation and overexpression of NCL are related to various pathologic and oncological indications. These characteristics of NCL make it an ideal target for the treatment of various cancers. AS1411 is a synthetic quadruplex-forming nuclease-resistant DNA oligonucleotide aptamer which shows a considerably high affinity for NCL, therefore, being capable of inducing growth inhibition in a variety of tumor cells. The high affinity and specificity of AS1411 towards NCL make it a suitable targeting tool, which can be used for the functionalization of therapeutic payloaddelivery nanosystems to selectively target tumor cells. This review explores the advances in NCL-targeting cancer therapy through AS1411-functionalized delivery nanosystems for the selective delivery of a broad spectrum of therapeutic agents.

A pH-Activatable MnCO3 Nanoparticle for Improved Magnetic Resonance Imaging of Tumor Malignancy and Metastasis

Engineered magnetic nanoparticles have been extensively explored for magnetic resonance imaging (MRI) diagnosis of a tumor to improve the visibility. However, most of these nanoparticles display "always-on" signals without tumor specificity, causing insufficient contrast and false positives. Here, we provide a new paradigm of MRI diagnosis using MnCO₃ nanorhombohedras (MnNRs) as an ultrasensitive T₁-weighted MRI contrast agent, which smartly enhances the MR signal in response to the tumor microenvironment. MnNRs would quickly decompose and release Mn²⁺ at mild acidity, one of the pathophysiological parameters associated with cancer malignancy, and then Mn²⁺ binds to surrounding proteins to achieve a remarkable amplification of T₁ relaxivity. In vivo MRI experiments demonstrate that MnNRs can selectively brighten subcutaneous tumors from the edge to the interior may be because of the upregulated vascular permeation at the tumor edge, where cancer cell proliferation and angiogenesis are more active. Specially, benefiting from the T₂ shortening effect in normal liver tissues, MnNRs can detect millimeter-sized liver metastases with an ultrahigh contrast of 294%. The results also indicate an effective hepatic excretion of MnNRs through the gallbladder. As such, this pH-activatable MRI strategy with facility, biocompatibility, and excellent efficiency may open new avenues for tumor malignancy and metastasis diagnosis and holds great promise for precision medicine.

Intracellular aggregation of peptide-reprogrammed small molecule nanoassemblies enhances cancer chemotherapy and combinatorial immunotherapy

The intracellular retention of nanotherapeutics is essential for their therapeutic activity. The immobilization of nanotherapeutics inside target cell types can regulate various cell behaviors. However, strategies for the intracellular immobilization of nanoparticles are limited. Herein, a cisplatin prodrug was synthesized and utilized as a glutathione (GSH)-activated linker to induce aggregation of the cisplatin prodrug/IR820/docetaxel nanoassembly. The nanoassembly has been reprogrammed with peptide-containing moieties for tumor-targeting and PD-1/PD-L1 blockade. The aggregation of the nanoassemblies is dependent on GSH concentration. Evaluations in vitro and in vivo revealed that GSH-induced intracellular aggregation of the nanoassemblies enhances therapeutic activity in primary tumors by enhancing the accumulation and prolonging the retention of the chemotherapeutics in the tumor site and inducing reactive oxygen species (ROS) generation and immunogenic cell death. Moreover, the nanoassemblies reinvigorate the immunocytes, especially the systemic immunocytes, and thereby alleviate pulmonary metastasis, even though the population of immunocytes in the primary tumor site is suppressed due to the enhanced accumulation of chemotherapeutics. This strategy provides a promising option for the intracellular immobilization of nanoparticles in vitro and in vivo.

Metal-ligand coordination nanomaterials for radiotherapy: emerging synergistic cancer therapy

Radiotherapy (RT) plays a central role in curing malignant tumors. However, the treatment outcome is often impeded by low radiation absorption coefficients and radiation resistance of tumors along with normal tissue radio-toxicity. With the development of nanotechnology, nanomaterials in combination with RT offer the possibility to improve the therapeutic efficacy yet reduce side-effects. Metal-ligand coordination nanomaterials, including nanoscale metal-organic frameworks (NMOFs) and nanoscale coordination polymers (NCPs), formed by coordination interactions between inorganic metal ions/clusters with organic bridging ligands, have shown great potential in the field of radiation oncology in recent years in view of their unique advantages including the porous structure, high surface area, periodic frameworks, and diverse selections of both metal ions/clusters and organic ligands. In this review, we summarize the recent advances in NMOF/NCP-mediated synergistic RT in combination with hypoxia relief, chemotherapy, photodynamic therapy, photothermal therapy, chemodynamic therapy or immunotherapy, which emerged in the last 3 years, and describe cooperative enhancement interactions among these synergistic combinations. Moreover, the potential challenges and future prospects of this rapidly growing direction were also addressed.

Cisplatin resistance reversal in lung cancer by tumor acidity-activable vesicular nanoreactors via tumor oxidative stress amplification

Drug resistance of cisplatin significantly limits its therapeutic efficacy in clinical applications against different cancers. Herein, we develop a novel strategy to overcome cisplatin drug resistance through sensitizing cisplatin-resistant human lung cancer cells (A549R) under amplified oxidative stress using a vesicular nanoreactor for simultaneous cisplatin delivery and H₂O₂ generation. We engineer the nanoreactor by the self-assembly of the amphiphilic diblock copolymers to co-deliver glucose oxidase (GOD) and cisplatin (Cis) (Cis/GOD@Bz-V). Cis/GOD@Bz-V was rationally designed to stay impermeable during blood circulation while mild acidity (pH 6.5-6.8) can activate its molecular-weight selective membrane permeability and release cisplatin locally. Diffusion of small molecules such as oxygen and glucose across the membranes can induce the in situ generation of superfluous H₂O₂ to promote cellular oxidative stress and sensitize A549R cells via activation of pro-apoptotic pathways. Cis/GOD@Bz-V nanoreactors could effectively kill A549R at pH 6.8 in the presence of glucose by the combination of H₂O₂ generation and cisplatin release. Growth of A549R xenograft tumors can be inhibited efficiently without the obvious toxic side effects via the systemic administration of Cis/GOD@Bz-V. Accordingly, the tumor acidity-activable cisplatin-loaded nanoreactors show great potential to enhance the therapeutic efficacy against cisplatin-resistant cancers.

Recent advances in peptide-targeted micelleplexes: Current developments and future perspectives

The decoding of the human genome revolutionized the understanding of how genetics influence the interplay between health and disease, in a multidisciplinary perspective. Thus, the development of exogenous nucleic acids-based therapies has increased to overcome hereditary or acquired genetic-associated diseases. Gene drug delivery using non-viral systems, for instance micelleplexes, have been recognized as promising options for gene-target therapies. Micelleplexes are core-shell structures, at a nanometric scale, designed using amphiphilic block copolymers. These can self-assemble in an aqueous medium, leading to the formation of a hydrophilic and positively charged corona - that can transport nucleic acids, - and a hydrophobic core - which can transport poor water-soluble drugs. However, the performance of these types of carriers usually is hindered by several in vivo barriers. Fortunately, due to a significant amount of research, strategies to overcome these shortcomings emerged. With a wide range of structural features, good stability against proteolytic degradation, affordable characteristic, easy synthesis, low immunogenicity, among other advantages, peptides have increasingly gained popularity as target ligands for non-viral carriers. Hence, this review addresses the use of peptides with micelleplexes illustrating, through the analysis of in vitro and in vivo studies, the potential and future perspectives of this combination.

Antibody-Conjugated Nanocarriers for Targeted Antibiotic Delivery: Application in the Treatment of Bacterial Biofilms

Conventional antibiotic treatment is in most cases insufficient to eradicate biofilm-related infections, resulting in high risk of treatment failure and recurrent infections. Recent studies have shown that novel methods of antibiotic delivery can improve clinical outcomes and reduce the emergence of antibiotic resistance. The objectives of this work were to develop and evaluate a targeting nanocarrier system that enables effective delivery of antimicrobial drugs to Staphylococcus aureus, a commonly virulent human pathogen. For this purpose, we first prepared a formulation of polymeric nanoparticles (NPs) suitable for encapsulation and sustained release of antibiotics. A specific antibody against S. aureus was used as a targeting ligand and was covalently immobilized onto the surface of nanoparticulate materials. It was demonstrated that the targeting NPs preferentially bound S. aureus cells and presented an elevated accumulation in the S. aureus biofilm. Compared to free-form antibiotic, the antibiotic-loaded targeting NPs significantly enhanced in vitro bactericidal activity against S. aureus both in planktonic and biofilm forms. Using a mouse infection model, we observed improved therapeutic efficacy of these antibiotic-loaded NPs after a single intravenous administration. Taken together, our studies show that the targeting nanoparticulate system could be a promising strategy to enhance the biodistribution of antibiotics and thereby improve their efficacy.

Management of Glioblastoma Multiforme by Phytochemicals: Applications of Nanoparticle-Based Targeted Drug Delivery System

The Glioblastoma Multiforme (GBM; grade IV astrocytoma) exhorts tumors of star-shaped glial cells in the brain. It is a fast-growing tumor that spreads to nearby brain regions specifically to cerebral hemispheres in frontal and temporal lobes. The etiology of GBM is unknown, but major risk factors are genetic disorders like neurofibromatosis and schwannomatosis, which develop the tumor in the nervous system. The management of GBM with chemo-radiotherapy leads to resistance, and current drug regimen like Temozolomide (TMZ) is less efficacious. The reasons behind the failure of drugs are due to DNA alkylation in the cell cycle by enzyme DNA guanidase and mitochondrial dysfunction. Naturally occurring bioactive compounds from plants referred as phytochemicals, serve as vital sources for anti-cancer drugs. Some prototypical examples include taxol analogs, vinca alkaloids (vincristine, vinblastine), podophyllotoxin analogs, camptothecin, curcumin, aloe-emodin, quercetin, berberine etc. These phytochemicals often regulate diverse molecular pathways, which are implicated in the growth and progression of cancers. However, the challenges posed by the presence of BBB/BBTB to restrict the passage of these phytochemicals, culminates in their low bioavailability and relative toxicity. In this review, we integrated nanotech as a novel drug delivery system to deliver phytochemicals from traditional medicine to the specific site within the brain for the management of GBM.

Polymeric micelles in drug delivery: An insight of the techniques for their characterization and assessment in biorelevant conditions

Polymeric micelles, i.e. aggregation colloids formed in solution by self-assembling of amphiphilic polymers, represent an innovative tool to overcome several issues related to drug administration, from the low water-solubility to the poor drug permeability across biological barriers. With respect to other nanocarriers, polymeric micelles generally display smaller size, easier preparation and sterilization processes, and good solubilization properties, unfortunately associated with a lower stability in biological fluids and a more complicated characterization. Particularly challenging is the study of their interaction with the biological environment, essential to predict the real in vivo behavior after administration. In this review, after a general presentation on micelles features and properties, different characterization techniques are discussed, from the ones used for the determination of micelles basic characteristics (critical micellar concentration, size, surface charge, morphology) to the more complex approaches used to figure out micelles kinetic stability, drug release and behavior in the presence of biological substrates (fluids, cells and tissues). The techniques presented (such as dynamic light scattering, AFM, cryo-TEM, X-ray scattering, FRET, symmetrical flow field-flow fractionation (AF4) and density ultracentrifugation), each one with their own advantages and limitations, can be combined to achieve a deeper comprehension of polymeric micelles in vivo behavior. The set-up and validation of adequate methods for micelles description represent the essential starting point for their development and clinical success.

Spatiotemporal Concurrent Liberation of Cytotoxins from Dual-Prodrug Nanomedicine for Synergistic Antitumor Therapy

Nanomedicine developed to date by means of directly encapsulating cytotoxins suffers from crucial drawbacks, including premature release and detoxification prior to arrival at pharmaceutics targets. To these respects, redox-responsive polymeric prodrugs of platinum (Pt) and camptothecin (CPT), selectively and concomitantly activated in the cytoplasm, were elaborated in manufacture of dual prodrug nanomedicine. Herein, multiple CPTs were conjugated to poly(lysine) (PLys) segments of block copolymeric poly(ethylene glycol) (PEG)-PLys through the redox responsive disulfide linkage [PEG-PLys(ss-CPT)] followed by reversible conversion of amino groups from PLys into carboxyl groups based on their reaction with cis-aconitic anhydride [PEG-PLys(ss-CPT&CAA)]. On the other hand, Pt(IV) in conjugation with dendritic polyamindoamine [(G3-PAMAM-Pt(IV)] was synthesized for electrostatic complexation with PEG-PLys(ss-CPT&CAA) into dual prodrug nanomedicine. Subsequent investigations proved that the elaborated nanomedicine could sequentially respond to intracellular chemical potentials to overcome a string of predefined biological barriers and facilitate intracellular trafficking. Notably, PEG-PLys(ss-CPT&CAA) capable of responding to the acidic endosomal microenvironment for transformation into endosome-disruptive PEG-PLys(ss-CPT), as well as release of G3-PAMAM-Pt(IV) from nanomedicine, prompted transclocation of therapeutic payloads from endosomes into cytosols. Moreover, concurrent activation and liberation of cytotoxic CPT and Pt(II) owing to their facile responsiveness to the cytoplasmic reducing microenvironment have demonstrated overwhelming cytotoxic potencies. Eventually, systemic administration of the dual prodrug construct exerted potent tumor suppression efficacy in treatment of intractable solid breast adenocarcinoma, as well as an appreciable safety profile. The present study illustrated the first example of nanomedicine with a dual prodrug motif, precisely and concomitantly activated by the same subcellular stimuli before approaching pharmaceutic action targets, thus shedding important implication in development of advanced nanomedicine to seek maximized pharmaceutic outcomes.

Sequential Modulations of Tumor Vasculature and Stromal Barriers Augment the Active Targeting Efficacy of Antibody-Modified Nanophotosensitizer in Desmoplastic Ovarian Carcinoma

Active-targeted nanoparticles are attractive carriers due to their potentials to facilitate specific delivery of drugs into tumor cells while sparing normal cells. However, the therapeutic outcomes of active-targeted nanomedicines are hampered by the multiple physiological barriers in the tumor microenvironment (TME). Herein, an epidermal growth factor receptor-targeted ultra-pH-sensitive nanophotosensitizer is fabricated, and the regulation of the TME to augment the active targeting ability and therapeutic efficacy is pinpointed. The results reveal that tumor vasculature normalization with thalidomide indiscriminately enhance the tumor accumulation of passive and active targeted nanoparticles, both of which are sequestered in the stromal bed of tumor mass. Whereas, photoablation of stromal cells located in perivascular regions significantly improves the accessibility of antibody-modified nanophotosensitizer to receptor-overexpressed cancer cells. After sequential regulation of TME, the antitumor efficacy of antibody-modified nanophotosensitizer is drastically enhanced through synergistic enhancements of tumor accumulation and cancer cell accessibility of active-targeted nanoparticles. The study offers deep insights about the intratumoral barriers that hinder the active-targeted nanoparticles delivery, and provides a basis for developing more effective strategies to accelerate the clinical translation of active-targeted nanomedicines.

Cathepsin B-responsive and gadolinium-labeled branched glycopolymer-PTX conjugate-derived nanotheranostics for cancer treatment

Multi-modal therapeutics are emerging for simultaneous diagnosis and treatment of cancer. Polymeric carriers are often employed for loading multiple drugs due to their versatility and controlled release of these drugs in response to a tumor specific microenvironment. A theranostic nanomedicine was designed and prepared by complexing a small gadolinium chelate, conjugating a chemotherapeutic drug PTX through a cathepsin B-responsive linker and covalently bonding a fluorescent probe pheophorbide a (Ppa) with a branched glycopolymer. The branched prodrug-based nanosystem was degradable in the tumor microenvironment with overexpressed cathepsin B, and PTX was simultaneously released to exert its therapeutic effect. The theranostic nanomedicine, branched glycopolymer-PTX-DOTA-Gd, had an extended circulation time, enhanced accumulation in tumors, and excellent biocompatibility with significantly reduced gadolinium ion (Gd³⁺) retention after 96 h post-injection. Enhanced imaging contrast up to 24 h post-injection and excellent antitumor efficacy with a tumor inhibition rate more than 90% were achieved from glycopolymer-PTX-DOTA-Gd without obvious systematic toxicity. This branched polymeric prodrug-based nanomedicine is very promising for safe and effective diagnosis and treatment of cancer.

•

A cathepsin B-responsive theranostic nanomedicine (glycopolymer-PTX-DOTA-Gd) based on a branched glycopolymer was prepared.

•

Glycopolymer-PTX-DOTA-Gd can be specifically degradated and release drug at tumor enviornment.

•

Glycopolymer-PTX-DOTA-Gd enhance the contrast of magnetic resonance imaging (MRI) at tumor sites.

•

The nanomedicine have good biocompatibility, excellent tumor targeting and anti-tumor efficacy.

Design of DOX-GNRs-PNIPAM@PEG-PLA Micelle With Temperature and Light Dual-Function for Potent Melanoma Therapy

Objective: The aim of this study was to construct light and temperature dual-sensitive micellar carriers loaded with doxorubicin (DOX) and gold nanorods (DOX-GNRs-PNIPAM@PEG-PLA, DAPP) for melanoma therapy. Methods: The DAPP self-assembled using fine-tuned physicochemical properties in water. The DAPP structure, temperature- and photo-sensitivity, drug-release, in-vitro serum stability, and cytotoxicity against melanoma B16F10 cells were evaluated in detail. The corresponding in-vitro and in-vivo therapeutic mechanisms were then evaluated using a B16F10-melanoma bearing BALB/c nude mouse model (B16F10). Results: The light and temperature sensitive micellar drug-delivery system assembled from block copolymer and gold nanorods exhibited a narrow particle size and size distribution, good biocompatibility, well-designed photo-temperature conversion, controlled drug release, and high serum stability. Compared with the free DOX- and PBS-treated groups, the cell endocytosis-mediated cytotoxicity and intra-tumor accumulation of DAPP was markedly enhanced by the NIR-light exposure and induced potent in-vivo tumor inhibitory activity. Conclusion: The design of DAPP, a dual-functional micellar drug-delivery system with temperature- and light-sensitive properties, offers a new strategy for skin-cancer therapy with a potent therapeutic index.

Antibody-activated trans-endothelial delivery of mesoporous organosilica nanomedicine augments tumor extravasation and anti-cancer immunotherapy

Tumor vasculature constitutes a formidable hurdle for the efficient delivery of cancer nanomedicine into tumors. The leverage of passive pathway through inter-endothelial gaps in tumor blood vessels might account for limited extravasation of nanomedicine into tumor microenvironment (TME). Herein, Annexin A1 antibody-installed mesoporous organosilica nanoplatforms carrying immunotherapeutics of anti-PD-L1 antibody (aPD-L1) and Indoximod are developed to target at caveolar Annexin-A1 protein of luminal endothelial cells and to trigger the active trans-endothelial transcytosis of nanomedicine mediated by caveolae. Such strategy enables rapid nanomedicine extravasation across tumor endothelium and relatively extensive accumulation in tumor interstitium. aPD-L1 and Indoximod release from aPD/IND@MON-aANN in a reduction-responsive manner and synergistically facilitate the intratumoral infiltration of cytotoxic T lymphocytes and reverse the immunosuppressive TME, thus demonstrating substantial anti-tumor efficacy in subcutaneous 4T1 breast tumors and remarkable anti-metastatic capacity to extend the survival of 4T1 tumor metastasis model. Moreover, aPD/IND@MON-aANN nanomedicine also exhibits distinct superiority over the combination therapy of free drugs to potently attenuate the progression of urethane-induced orthotopic lung cancers. Collectively, aPD/IND@MON-aANN nanoplatforms with boosted delivery efficiency via antibody-activated trans-endothelial pathway and enhanced immunotherapeutic efficacy provides perspectives for the development of cancer nanomedicines.

•

The nanomedicine overcomes tumor vascular barrier by active transcytosis via caveolae initiated by the conjugated aANXA1.

•

The nanoplatform responsively releases aPD-L1 and Indoximod to synergistically improve the efficacy of immunotherapy.

•

The nanomedicine shows anti-tumor capacity in mice breast cancers and lung cancers.

Targeted-delivery of siRNA via a polypeptide-modified liposome for the treatment of gp96 over-expressed breast cancer

Targeted gene therapy has led to significant breakthroughs in cancer treatment. Heat shock protein gp96 is an emerging target for tumor treatment because of its transfer ability from reticulum to tumor cell surface. CDO14 is a peptide cationic liposome developed in our laboratory with higher gene transfection efficiency and lower toxicity compared with the existing cationic liposomes. In this study, gp96-targeted liposome p37-CDO14 was constructed by modifying cationic liposome CDO14 with a gp96 inhibitor, helical polypeptide p37. Liposome p37-CDO14 could specifically bind to breast cancer cells with gp96-overexpression on the cell membrane. Both liposomes CDO14 and p37-CDO14 showed high delivery efficiency for survivin siRNA (siSuvi) to SK-BR-3 and MCF-7 cells via obviously decreased survivin expression level and cell viability. P37-CDO14 significantly increased the accumulation of FAM-siRNA in tumor compared with CDO14. SiSuvi transfected by CDO14 and p37-CDO14 could inhibit the growth of xenograft in mice and the expression of survivin in tumor tissues. The anti-tumor effect of siSuvi delivered by p37-CDO14 was much higher than that delivered by CDO14. This suggests that targeted liposome p37-CDO14 is a potential gene vector for the therapy of gp96 overexpressed breast cancer.

Functional metal-organic framework-based nanocarriers for accurate magnetic resonance imaging and effective eradication of breast tumor and lung metastasis

The use of nanoscale metal-organic frameworks (MOFs) as drug delivery vehicles has attracted considerable attention in tumor therapy. In this study, novel biocompatible MOF-based nanocarriers were used as part of a facile and reproducible strategy for precision cancer theranostics. Both diagnostic (Mn²⁺) and therapeutic compounds (doxorubicin, DOX) were incorporated into the multifunctional MOF-based nanocarriers, which exhibited high colloidal stability and promoted T₁-weighted proton relaxivity and low-pH-activated drug release. The obtained MOF-based nanocarriers exhibited significantly high cellular uptake and efficient intracellular drug delivery into cancer cells, which resulted in high apoptosis and cytotoxicity, in addition to effectively inhibiting the migration of 4T1 breast cancer cells. Moreover, the MOF-based nanocarriers could intensively deliver diagnostic and therapeutic agents to tumors to enable precise visualization of the nanocarrier accumulation and accurate tumor positioning, diagnosis, and imaging-guided therapy using magnetic resonance imaging (MRI). In addition, the functional MOF-based nanocarriers exhibited effective ablation of the primary breast cancer, as well as significant inhibition of lung metastasis with a high survival rate. Therefore, the developed nanocarriers represent a viable platform for cancer theranostics.

A design strategy of ultrasmall Gd2O3 nanoparticles for T1 MRI with high performance

Proposing a design strategy of Gd³⁺ based nanoparticles for high performance magnetic resonance imaging.

Chemo-physical Strategies to Advance the in Vivo Functionality of Targeted Nanomedicine: The Next Generation

The past few decades have witnessed an evolution of nanomedicine from biologically inert entities to more smart systems, aimed at advancing in vivo functionality. However, we should recognize that most systems still rely on reasonable explanation-including some over-explanation-rather than definitive evidence, which is a watershed radically determining the speed and extent of advancing nanomedicine. Probing nano-bio interactions and desirable functionality at the tissue, cellular, and molecular levels is most frequently overlooked. Progress toward answering these questions will provide instructive insight guiding more effective chemo-physical strategies. Thus, in the next generation, we argue that much effort should be made to provide definitive evidence for proof-of-mechanism, in lieu of creating many new and complicated systems for similar proof-of-concept.