Lipid-assisted PEG-b-PLA nanoparticles with ultrahigh SN38 loading capability for efficient cancer therapy.

The topoisomerase I inhibitor, 7-ethyl-10-hydroxycamptothecin (SN38), has demonstrated potent anticancer activity. However, its clinical application is hindered by its low solubility and high crystallization propensity, which further complicates its encapsulation into nanoparticles for systemic delivery. Herein, we explore the utilization of lipid-assisted poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-b-PLA) nanoparticles to achieve ultrahigh loading capability for SN38. Through the introduction of cationic, anionic, or neutral lipids, the SN38 loading efficiency and loading capacity is elevated to >90% and >10% respectively. These lipids efficiently attenuate the intermolecular π-π stacking of SN38, thereby disrupting its crystalline structure. Moreover, we assess the therapeutic activity of SN38-loaded formulations in various tumor models and identify an anionic lipid 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) sodium salt (DOPG)-assisted formulation that exhibits the highest anticancer activity and has favorable biosafety. Overall, our findings present a simple and robust strategy to achieve ultrahigh loading efficiency of SN38 using commonly employed PEG-b-PLA nanoparticles, opening up a new avenue for the systemic delivery of SN38.

Mallory-Weiss syndrome in four hemodialysis patients: a case study.

BACKGROUND: Hemodialysis patients are prone to gastrointestinal bleeding, and Mallory-Weiss syndrome (MWS) is one of the causes. Mallory-Weiss syndrome is often induced by severe vomiting, manifests as upper gastrointestinal bleeding, and is self-limited with a good prognosis. However, mild vomiting in hemodialysis patients can lead to the occurrence of MWS, and the mild early symptoms are easy to misdiagnose, leading to the aggravation of the disease. CASE PRESENTATION: In this paper, we report four hemodialysis patients with MWS. All patients displayed symptoms of upper gastrointestinal bleeding. The diagnosis of MWS was confirmed by gastroscopy. One patient had a history of severe vomiting; however, the other three reported histories of mild vomiting. Three patients received the conservative hemostasis treatment, and the gastrointestinal bleeding stopped. One patient underwent the gastroscopic and interventional hemostasis treatments. The conditions of three of the patients improved. Unfortunately, one of the patients died due to the cardia insufficiency. CONCLUSIONS: We think that the mild symptoms of MWS are easily covered up by other symptoms. This may lead to delays in diagnosis and treatment. For patients with severe symptoms, gastroscopic hemostasis is still the first choice, and interventional hemostasis can also be considered. For patients with mild symptoms, drug hemostasis is the first consideration.

Anchoring super-enhancer-driven oncogenic lncRNAs for anti-tumor therapy in hepatocellular carcinoma.

Super-enhancer (SE) plays a vital role in the determination of cell identity and fate. Up-regulated expression of coding genes is frequently associated with SE. However, the transcription dysregulation driven by SE, from the viewpoint of long non-coding RNA (lncRNA), remains unclear. Here, SE-associated lncRNAs in HCC are comprehensively outlined for the first time. This study integrally screens and identifies several novel SE-associated lncRNAs that are highly abundant and sensitive to JQ1. Especially, HSAL3 is identified as an uncharacterized SE-driven oncogenic lncRNA, which is activated by transcription factors HCFC1 and HSF1 via its super-enhancer. HSAL3 interference negatively regulates NOTCH signaling, implying the potential mechanism of its tumor-promoting role. The expression of HSAL3 is increased in HCC samples, and higher HSAL3 expression indicates an inferior overall survival of HCC patients. Furthermore, siHSAL3 loaded nanoparticles exert anti-tumor effect on HCC in vitro and in vivo. In conclusion, this is the first comprehensive survey of SE-associated lncRNAs in HCC. HSAL3 is a novel SE-driven oncogenic lncRNA, and siHSAL3 loaded nanoparticles are therapeutic candidates for HCC. This work sheds lights on the merit of anchoring SE-driven oncogenic lncRNAs for HCC treatment.

Immunomodulating nano-adaptors potentiate antibody-based cancer immunotherapy.

Modulating effector immune cells via monoclonal antibodies (mAbs) and facilitating the co-engagement of T cells and tumor cells via chimeric antigen receptor- T cells or bispecific T cell-engaging antibodies are two typical cancer immunotherapy approaches. We speculated that immobilizing two types of mAbs against effector cells and tumor cells on a single nanoparticle could integrate the functions of these two approaches, as the engineered formulation (immunomodulating nano-adaptor, imNA) could potentially associate with both cells and bridge them together like an 'adaptor' while maintaining the immunomodulatory properties of the parental mAbs. However, existing mAbs-immobilization strategies mainly rely on a chemical reaction, a process that is rough and difficult to control. Here, we build up a versatile antibody immobilization platform by conjugating anti-IgG (Fc specific) antibody (αFc) onto the nanoparticle surface (αFc-NP), and confirm that αFc-NP could conveniently and efficiently immobilize two types of mAbs through Fc-specific noncovalent interactions to form imNAs. Finally, we validate the superiority of imNAs over the mixture of parental mAbs in T cell-, natural killer cell- and macrophage-mediated antitumor immune responses in multiple murine tumor models.

Macrophage-Specific in Vivo Gene Editing Using Cationic Lipid-Assisted Polymeric Nanoparticles.

The CRISPR/Cas9 gene editing technology holds promise for the treatment of multiple diseases. However, the inability to perform specific gene editing in targeted tissues and cells, which may cause off-target effects, is one of the critical bottlenecks for therapeutic application of CRISPR/Cas9. Herein, macrophage-specific promoter-driven Cas9 expression plasmids (pM458 and pM330) were constructed and encapsulated in cationic lipid-assisted PEG-b-PLGA nanoparticles (CLAN). The obtained nanoparticles encapsulating the CRISPR/Cas9 plasmids were able to specifically express Cas9 in macrophages as well as their precursor monocytes both in vitro and in vivo. More importantly, after further encoding a guide RNA targeting Ntn1 (sgNtn1) into the plasmid, the resultant CLANpM330/sgNtn1 successfully disrupted the Ntn1 gene in macrophages and their precursor monocytes in vivo, which reduced expression of netrin-1 (encoded by Ntn1) and subsequently improved type 2 diabetes (T2D) symptoms. Meanwhile, the Ntn1 gene was not disrupted in other cells due to specific expression of Cas9 by the CD68 promoter. This strategy provides alternative avenues for specific in vivo gene editing with the CRISPR/Cas9 system.

Sequential growth of CaF2:Yb,Er@CaF2:Gd nanoparticles for efficient magnetic resonance angiography and tumor diagnosis.

It is a significant challenge to develop nanoscale magnetic resonance imaging (MRI) contrast agents with high performance of relaxation. In this work, Gd3+-doped CaF2-based core-shell nanoparticles (CaF2:Yb,Er@CaF2:Gd) of sub-10 nm size were controllably synthesized by a facile sequential growth method. The as-prepared hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles modified using PEG-PAA di-block copolymer benefited from the presence of Gd only in the outer CaF2 layer of the nanoparticles, which exhibited r1 as high as 21.86 mM-1 s-1 under 3.0 T, seven times as high as that of commercially used gadopentetate dimeglumine (Gd-DTPA). Low cytotoxicity, no hemolysis phenomenon and no potential gadolinium ion leakage phenomenon of the hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles have been observed and confirmed. Clear vascular details can be observed in magnetic resonance angiography and obvious MR signal of 4T1 tumor area could be significantly improved by intravenous injection of the hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles at a low dosage in mice. A series of in vivo biological safety evaluations confirmed the good biocompatibility of the hydrophilic CaF2:Yb,Er@CaF2:Gd nanoparticles, which might be employed in clinical blood pool imaging and tumor diagnosis as a safe and efficient MRI probe.

Spatial Targeting of Tumor-Associated Macrophages and Tumor Cells with a pH-Sensitive Cluster Nanocarrier for Cancer Chemoimmunotherapy.

Chemoimmunotherapy, which combines chemotherapeutics with immune-modulating agents, represents an appealing approach for improving cancer therapy. To optimize its therapeutic efficacy, differentially delivering multiple therapeutic drugs to target cells is desirable. Here we developed an immunostimulatory nanocarrier (denoted as BLZ-945SCNs/Pt) that could spatially target tumor-associated macrophages (TAMs) and tumor cells for cancer chemoimmunotherapy. BLZ-945SCNs/Pt undergo supersensitive structure collapse in the prevascular regions of tumor tissues and enable the simultaneous release of platinum (Pt)-prodrug conjugated small particles and BLZ-945, a small molecule inhibitor of colony stimulating factor 1 receptor (CSF-1R) of TAMs. The released BLZ-945 can be preferentially taken up by TAMs to cause TAMs depletion from tumor tissues, while the small particles carrying Pt-prodrug enable deep tumor penetration as well as intracellularly specific drug release to kill more cancer cells. Our studies demonstrate that BLZ-945SCNs/Pt outperform their monotherapy counterparts in multiple tumor models. The underlying mechanism studies suggest that the designer pH-sensitive codelivery nanocarrier not only induces apoptosis of tumor cells but also modulates the tumor immune environment to eventually augment the antitumor effect of CD8+ cytotoxic T cells through TAMs depletion.

Responsive Nanocarriers as an Emerging Platform for Cascaded Delivery of Nucleic Acids to Cancer.

Cascades of systemic and intracellular obstacles, including low stability in blood, little tumor accumulation, weak tumor penetration, poor cellular uptake, inefficient endosomal escape and deficient disassembly in the cytoplasm, must be overcome in order to deliver nucleic acid drugs for cancer therapy. Nanocarriers that are sensitive to a variety of physiological stimuli, such as pH, redox status, and cell enzymes, are substantially changing the landscape of nucleic acid drug delivery by helping to overcome cascaded systemic and intracellular barriers. This review discusses nucleic acid-based therapeutics, systemic and intracellular barriers to efficient nucleic acid delivery, and nanocarriers responsive to extracellular and intracellular biological stimuli to overcome individual barriers. In particular, responsive nanocarriers for the cascaded delivery of nucleic acids in vivo are highlighted. Developing novel cascaded nanocarriers that transform their physicochemical properties in response to various stimuli in a timely and spatially controlled manner for nucleic acid drug delivery holds great potential for translating the promise of nucleic acid drugs and achieving clinically successful cancer therapy.

Controlled synthesis of upconverting nanoparticles/CuS yolk-shell nanoparticles for in vitro synergistic photothermal and photodynamic therapy of cancer cells.

Synergistic photodynamic and photothermal therapy of cancer cells is of considerable scientific and technological interest. In this work, we demonstrate a sacrificial template strategy to fabricate yolk-shell nanoparticles combining upconversion nanoparticles (UCNPs) and CuS nanoparticles. Lanthanide-doped upconversion nanoparticles of NaYF4:30% Yb,1% Nd,0.5% Er@NaYF4:20% Nd (also denoted as UCNPs) have been prepared as 808 nm light excited remote-controlled nanotransducers for in vitro cancer cell treatment. The upconversion fluorescence of the as-prepared UCNPs@CuS yolk-shell nanoparticles is completely quenched under the excitation of an 808 nm laser, which demonstrates that the energy transfer between the UCNPs and CuS is very efficient. In addition, the as-prepared UCNPs@CuS nanoparticles show higher production ability for hydroxyl radicals (˙OH) and singlet oxygen (1O2) compared to CuS hollow nanospheres of similar size. In particular, the excited shell layer (CuS) showed an enhanced photothermal effect while producing reactive oxygen species (ROS) including singlet oxygen (1O2) and hydroxyl radicals (˙OH) after being exposed to near infrared (NIR) light. Thus, the as-prepared UCNPs@CuS yolk-shell nanoparticles exhibited the synergistic effect of photothermal and photodynamic therapy of cancer cells, which resulted in significant cell death after exposure to an 808 nm laser. The synthetic strategy will provide an alternative method to fabricate other UCNP based core-shell nanoparticles for potential and important applications in bionanotechnology including theranostics, multimodal treatment, magnetic resonance imaging-guided photodynamic therapy, etc.

A Donor-Acceptor Conjugated Polymer with Alternating Isoindigo Derivative and Bithiophene Units for Near-Infrared Modulated Cancer Thermo-Chemotherapy.

Conjugated polymers containing alternating donor/acceptor units have strong and sharp absorbance peaks in near-infrared (NIR) region, which could be suitable for photothermal therapy. However, these polymers as photothermal transducers are rarely reported because of their water insolubility, which limits their applications for cancer therapy. Herein, we report the donor-acceptor conjugated polymer PBIBDF-BT with alternating isoindigo derivative (BIBDF) and bithiophene (BT) units as a novel photothermal transducer, which exhibited strong near-infrared (NIR) absorbance due to its low band gap (1.52 eV). To stabilize the conjugated polymer physiological environments, we utilized an amphiphilic copolymer, poly(ethylene glycol)-block-poly(hexyl ethylene phosphate) (mPEG-b-PHEP), to stabilize PBIBDF-BT-based nanoparticles (PBIBDF-BT@NPPPE) through a single emulsion method. The obtained nanoparticles PBIBDF-BT@NPPPE showed great stability in physiological environments and excellent photostability. Moreover, the PBIBDF-BT@NPPPE exhibited high photothermal conversion efficiency, reaching 46.7%, which is relatively high compared with those of commonly used materials for photothermal therapy. Accordingly, in vivo and in vitro experiments demonstrated that PBIBDF-BT@NPPPE exhibits efficient photothermal anticancer efficacy. More importantly, PBIBDF-BT@NPPPE could simultaneously encapsulate other types of therapeutic agents though hydrophobic interactions with the PHEP core and achieve NIR-triggered intracellular drug release and a synergistic combination therapy of thermo-chemotherapy for the treatment of cancer.

Stimuli-responsive clustered nanoparticles for improved tumor penetration and therapeutic efficacy.

A principal goal of cancer nanomedicine is to deliver therapeutics effectively to cancer cells within solid tumors. However, there are a series of biological barriers that impede nanomedicine from reaching target cells. Here, we report a stimuli-responsive clustered nanoparticle to systematically overcome these multiple barriers by sequentially responding to the endogenous attributes of the tumor microenvironment. The smart polymeric clustered nanoparticle (iCluster) has an initial size of ∼100 nm, which is favorable for long blood circulation and high propensity of extravasation through tumor vascular fenestrations. Once iCluster accumulates at tumor sites, the intrinsic tumor extracellular acidity would trigger the discharge of platinum prodrug-conjugated poly(amidoamine) dendrimers (diameter ∼5 nm). Such a structural alteration greatly facilitates tumor penetration and cell internalization of the therapeutics. The internalized dendrimer prodrugs are further reduced intracellularly to release cisplatin to kill cancer cells. The superior in vivo antitumor activities of iCluster are validated in varying intractable tumor models including poorly permeable pancreatic cancer, drug-resistant cancer, and metastatic cancer, demonstrating its versatility and broad applicability.

Tumor acidity-sensitive linkage-bridged block copolymer for therapeutic siRNA delivery.

The design of ideal nanoparticle delivery systems should be capable of meeting the requirements of several stages of drug delivery, including prolonged circulation, enhanced accumulation and penetration in the tumor, facilitated cellular internalization and rapid release of the active drug in the tumor cells. However, among the current design strategies, meeting the requirements of one stage often conflicts with the other. Herein, a tumor pH-labile linkage-bridged block copolymer of poly(ethylene glycol) with poly(lacide-co-glycolide) (PEG-Dlinkm-PLGA) was used for siRNA delivery to fulfill all aforementioned requirements of these delivery stages. The obtained siRNA-encapsulating PEG-Dlinkm-PLGA nanoparticle gained efficiently prolonged circulation in the blood and preferential accumulation in tumor sites via the PEGylation. Furthermore, the PEG surface layer was detached in response to the tumor acidic microenvironment to facilitate cellular uptake, and the siRNA was rapidly released within tumor cells due to the hydrophobic PLGA layer. Hence, PEG-Dlinkm-PLGA nanoparticles met the requirements of several stages of drug delivery, and resulted in the enhanced therapeutic effect of the nanoparticular delivery systems.

Tumor Acidity-Sensitive Polymeric Vector for Active Targeted siRNA Delivery.

Although surface PEGylation of siRNA vectors is effective for preventing protein adsorption and thereby helps these vectors to evade the reticuloendothelial system (RES) in vivo, it also suppresses the cellular uptake of these vectors by target cells. This dilemma could be overcome by employing stimuli-responsive shell-detachable nanovectors to achieve enhanced cellular internalization while maintaining prolonged blood circulation. Among the possible stimuli, dysregulated pH in tumor (pHe) is the most universal and practical. However, the design of pHe-sensitive system is problematic because of the subtle differences between the pHe and pH in other tissues. Here, a simple acid-sensitive bridged copolymer is developed and used for tumor-targeted systemic delivery of siRNA. After forming the micelleplex delivery system, the corresponding nanoparticles (Dm-NP) might undergo several modifications as follows: (i) a poly(ethylene glycol) (PEG) corona, which is stable in the circulatory system and protects nanovectors from RES clearance; (ii) a pHe responsive linkage breakage, which induces PEG detachment at tumor sites and thereby facilitates cell targeting; and (iii) a cell-penetration peptide, which is exposed upon the removal of PEG and further enhances cellular uptake. Thus, Dm-NP achieved both prolonged circulation and effective accumulation in tumor cells and resulted in the safe and enhanced inhibition of non-small cell lung cancer growth.

Redox-Responsive Polyphosphoester-Based Micellar Nanomedicines for Overriding Chemoresistance in Breast Cancer Cells.

Multidrug resistance (MDR) has been recognized as a key factor contributing to the failure of chemotherapy for cancer in the clinic, often due to insufficient delivery of anticancer drugs to target cells. For addressing this issue, a redox-responsive polyphosphoester-based micellar nanomedicine, which can be triggered to release transported drugs in tumor cells, has been developed. The micelles are composed of diblock copolymers with a hydrophilic PEG block and a hydrophobic polyphosphoester (PPE) block bearing a disulfide bond in a side group. After incubating the redox-responsive micelles with drug-resistant tumor cells, the intracellular accumulation and retention of DOX were significantly enhanced. Moreover, after internalization by MDR cancer cells, the disulfide bond in the side group was cleaved by the high intracellular glutathione levels, resulting in a hydrophobic to hydrophilic transition of the PPE block and subsequent disassembly of the micelles. Thus, the encapsulated DOX was rapidly released, and abrogation of drug resistance in the cancer cells was observed in vitro. Moreover, the DOX-loaded redox-responsive micelles exhibited significantly enhanced inhibition of tumor growth in nude mice bearing MCF-7/ADR xenograft tumors via tail vein injection, indicating that such micelles have great potential in overcoming MDR for cancer therapy.

Regulating the surface poly(ethylene glycol) density of polymeric nanoparticles and evaluating its role in drug delivery in vivo.

Poly(ethylene glycol) (PEG) is usually used to protect nanoparticles from rapid clearance in blood. The effects are highly dependent on the surface PEG density of nanoparticles. However, there lacks a detailed and informative study in PEG density and in vivo drug delivery due to the critical techniques to precisely control the surface PEG density when maintaining other nano-properties. Here, we regulated the polymeric nanoparticles' size and surface PEG density by incorporating poly(ε-caprolactone) (PCL) homopolymer into poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) and adjusting the mass ratio of PCL to PEG-PCL during the nanoparticles preparation. We further developed a library of polymeric nanoparticles with different but controllable sizes and surface PEG densities by changing the molecular weight of the PCL block in PEG-PCL and tuning the molar ratio of repeating units of PCL (CL) to that of PEG (EG). We thus obtained a group of nanoparticles with variable surface PEG densities but with other nano-properties identical, and investigated the effects of surface PEG densities on the biological behaviors of nanoparticles in mice. We found that, high surface PEG density made the nanoparticles resistant to absorption of serum protein and uptake by macrophages, leading to a greater accumulation of nanoparticles in tumor tissue, which recuperated the defects of decreased internalization by tumor cells, resulting in superior antitumor efficacy when carrying docetaxel.

Chlorin e6-Encapsulated Polyphosphoester Based Nanocarriers with Viscous Flow Core for Effective Treatment of Pancreatic Cancer.

Lack of effective treatment results in the low survival for patients with pancreatic cancer, and photodynamic therapy (PDT) with photosensitizers has emerged as an effective therapeutic option for treatment of various tumors by light-generated cytotoxic reactive oxygen species (ROS) to induce cell apoptosis or necrosis. However, the poor solubility, rapid blood clearance, and weak internalization of the photosensitizer seriously inhibit its anticancer efficacy. To overcome these obstacles, a polyphosphoester-based nanocarrier (NP-PPE) is employed as the carrier of the hydrophobic photosensitizer, chlorin e6 (Ce6), for photodynamic therapy. The Ce6-encapsulated nanocarrier (NP-PPE/Ce6) significantly promoted the cellular internalization of Ce6, enhanced the generation of ROS in the tumor cells after irradiation. Therefore, the cellular phototoxicity of NP-PPE/Ce6 against BxPC-3 pancreatic cancer cells was markedly enhanced than that of free Ce6 in vitro. Furthermore, NP-PPE/Ce6 improved accumulation of Ce6 in tumor tissue and treatment with NP-PPE/Ce6 significantly enhanced antitumor efficacy in human BxPC-3 pancreatic cancer xenografts. These results suggest that using a polyphosphoester-based nanocarrier as the delivery system for a photosensitizer has great potential for PDT of pancreatic cancer.

A block copolymer of zwitterionic polyphosphoester and polylactic acid for drug delivery.

Polymeric nanoparticles have been widely used as nano-drug delivery systems in preclinical and clinical trials for cancer therapy, and these systems usually need to be sterically stabilized by poly(ethylene glycol) (PEG) to maintain stability and avoid rapid clearance by the immune system. Recently, zwitterionic materials have been demonstrated to be potential alternatives to the classic PEG. Herein, we developed two drug delivery systems stabilized by zwitterionic polyphosphoesters. These nanoparticles showed favourable stability and anti-protein absorption ability in vitro. Meanwhile, as drug carriers, these zwitterionic polyphosphoester-stabilized nanoparticles significantly prolonged drug circulation half-lives and increased drug accumulation in tumors, which was comparable to PEG-stabilized nanoparticles. Systemic delivery of doxorubicin (DOX) by zwitterionic polyphosphoester-stabilized nanoparticles significantly inhibited tumor growth in a MDA-MB-231 tumor model, suggesting the potential of zwitterionic polyphosphoester-based nanoparticles in anticancer drug delivery.