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Chemotherapy for peritoneal dissemination is poorly effective owing to limited drug transfer from the blood to the intraperitoneal (i.p.) compartment after intravenous (i.v.) administration. i.p. chemotherapy has been investigated to improve drug delivery to tumors; however, the efficacy continues to be debated. As anticancer drugs have low molecular weight and are rapidly excreted through the peritoneal blood vessels, maintaining the i.p. concentration as high as expected is a challenge. In this study, we examined whether i.p. administration is an efficient route of administration of high-molecular-weight immune checkpoint inhibitors (ICIs) for the treatment of peritoneal dissemination using a model of peritoneal disseminated carcinoma. After i.p. administration, the amount of anti-PD-L1 antibody transferred into i.p. tumors increased by approximately eight folds compared to that after i.v. administration. Intratumoral distribution analysis revealed that anti-PD-L1 antibodies were delivered directly from the i.p. space to the surface of tumor tissue, and that they deeply penetrated the tumor tissues after i.p. administration; in contrast, after i.v. administration, anti-PD-L1 antibodies were only distributed around blood vessels in tumor tissues via the enhanced permeability and retention (EPR) effect. Owing to the enhanced delivery, the therapeutic efficacy of anti-PD-L1 antibody in the peritoneal dissemination models was also improved after i.p. administration compared to that after i.v. administration. This is the first study to clearly demonstrate an EPR-independent delivery of ICIs to i.p. tumors by which ICIs were delivered in a massive amount to the tumor tissue via direct penetration after i.p. administration.

Background Retiform hemangioendothelioma (RH) is a rare, intermediate-grade vascular tumor that often arises in the trunk and extremities. The clinical and radiological features of RH remain largely unknown. Case presentation A male patient in his 70s presented with shortness of breath on exertion, and computed tomography incidentally revealed a tumor in his right breast. Positron emission tomography (PET) revealed moderate 18F-fluorodeoxyglucose (FDG) uptake in the tumor. RH was observed in the resected specimens. Three months after surgery, the patient was free of local recurrence and distant metastasis. Conclusions RH was found in the male breast and was accompanied by FDG uptake on PET. PET may be useful in diagnosing RH. Although metastasis is rare in RH, local recurrence may occur, and careful follow-up is required.

A cellular assay for evaluating the binding and internalization of biologics using primary human liver sinusoidal endothelial cells (LSEC) is not readily available, since human LSEC generally lose their receptor expression and internalization activity during the purifying processes and cell culturing. Here, we propose a novel cell-based assay using human liver non-parenchymal cells (NPC) as an alternative method using LSEC. To identify the LSEC population, NPC were stained with CD31 and CD45, and analyzed by flow cytometry. The expression of Fc gamma receptor IIB (FcγRIIB), one of the LSEC markers was detected in the CD31-positive and the CD45-negative fractions. The concentration-dependent binding and internalization of the anti-FcγRIIB antibody was also quantified in the LSEC fraction in human NPC. Saturated binding and internalization curves were obtained for the anti-FcγRIIB antibody. In the case of the negative control antibody, however, binding and internalization were negligible. The findings reported here indicate that cell-based assays using fresh human liver NPC will be useful for evaluating the binding and internalization of biologics as well as for determining pharmacokinetic parameters.

Lipid nanoparticles (LNPs) are one of the most successful technologies in mRNA delivery. While the liver has been the most frequent target for LNP delivery of mRNA, technologies for delivering mRNA molecules to extrahepatic tissues are also important. Herein, we report on the development of a LNP that targets secondary lymphoid tissues. We designed new types of alcohol-soluble phosphatidylserine (PS) derivatives as materials which target immune cells, and then incorporated them into LNPs using a microfluidic technique with a high degree of scalability and reproducibility. The resulting LNP that contained the synthesized PS delivered mRNA to the spleen much more efficiently compared to a control LNP. A sub-organ analysis revealed that the PS-loaded LNP was extensively taken up by tissue-resident macrophages in the red pulp and the marginal zone of the spleen. Thus, the PS-loaded LNP reported in this study would be a promising strategy for clinical applications that involve delivering mRNA to the spleen. This article is protected by copyright. All rights reserved.

BackgroundWith the increased use of immune checkpoint inhibitors (ICIs), side effects and toxicity are a great concern. Anaphylaxis has been identified as a potential adverse event induced by ICIs. Anaphylaxis is a life-threatening medical emergency. However, the mechanisms and factors that can potentially influence the incidence and severity of anaphylaxis in patients with cancer remain unclear.MethodsHealthy, murine colon 26, CT26, breast 4T1, EMT6, and renal RENCA tumor-bearing mice were treated with an anti-PD-L1 antibody (clone 10F.9G2). Symptoms of anaphylaxis were evaluated along with body temperature and mortality. The amounts of antidrug antibody and platelet-activating factor (PAF) in the blood were quantified via ELISA and liquid chromatography-mass spectrometry (LC-MS/MS). Immune cells were analyzed and isolated using a flow cytometer and magnetic-activated cell sorting, respectively.ResultsRepeated administration of the anti-PD-L1 antibody 10F.9G2 to tumor-bearing mice caused fatal anaphylaxis, depending on the type of tumor model. After administration, antidrug immunoglobulin G (IgG), but not IgE antibodies, were produced, and PAF was released as a chemical mediator during anaphylaxis, indicating that anaphylaxis was caused by an IgG-dependent pathway. Anaphylaxis induced by 10F.9G2 was treated with a PAF receptor antagonist. We identified that neutrophils and macrophages were PAF-producing effector cells during anaphylaxis, and the tumor-bearing models with increased numbers of neutrophils and macrophages showed lethal anaphylaxis after treatment with 10F.9G2. Depletion of both neutrophils and macrophages using clodronate liposomes prevented anaphylaxis in tumor-bearing mice.ConclusionsThus, increased numbers of neutrophils and macrophages associated with cancer progression may be risk factors for anaphylaxis. These findings may provide useful insights into the mechanism of anaphylaxis following the administration of immune checkpoint inhibitors in human subjects.

Systemically administered lipid nanoparticles (LNPs) are complexed with Apolipoprotein E (ApoE) in the bloodstream, and the complex is subsequently largely taken up by hepatocytes. Based on a previous report showing that, like blood, lymph fluid also contains ApoE, and that LECs, in turn, expresses a low density-lipoprotein receptor (LDLR), which is the receptor responsible for the ApoE-bound LNP, we hypothesized that subcutaneously administered LNPs would be taken up by LECs via an ApoE-LDLR pathway. Our in vitro studies using immortal LECs that we established in a previous study showed that LEC indeed took up LNPs in an ApoE-dependent manner. We then reported on the development of LNPs that target the lymphatic endothelium for in vivo siRNA delivery after subcutaneous administration. The key to success for in vivo LEC targeting is that the surface needs to be modified with a high density of polyethylene glycol (PEG)-conjugated lipids with short acyl chains (C14). The LNPs were drained into the lymphatic system, and then accumulated in lymphatic endothelial cells in an ApoE-dependent manner, most likely after the release of the PEG-lipid. Subcutaneous administration of optimized LNPs containing encapsulated siRNA against VEGFR3, a marker of LECs, significantly inhibited the expression of VEGFR3. These findings are the first report of a simple straightforward strategy for targeting lymphatic endothelial cells by using ionizable lipid-formulated LNPs.

The sentinel lymph node (LN) is the first LN to which lymph fluid flows from tumor tissue. We identified the key parameters of liposomes (LPs) that affect their accumulation in regional (primary) LNs with minimum leakage to its connecting (secondary) LNs by a comprehensive analysis of the LN-to-LN trafficking of LPs with various surface charges and various sizes. We used a lymphatic flow-modified (LFM) mouse that allows for the chronological analysis of inguinal (primary) LN-to-axillary (secondary) LN at the body surface. As a result, the anionic medium-sized LPs (130 nm on average) exhibited the highest accumulation in the primary LNs. A mechanism-based analysis revealed that CD169-positive macrophages in LNs were the dominant cell population that captures anionic LPs. Sentinel LN imaging was also performed by the intratumoral injection of fluorescent medium-sized anionic LPs using a breast cancer orthotopic model. In comparison with the typically used contrast agent indocyanine green, the anionic LPs were detected in sentinel LNs with a high sensitivity. Additionally, the co-injection of hyaluronidase significantly improved the sensitivity of detection of the fluorescent LPs in sentinel LNs. In conclusion, medium-sized anionic LPs combined with hyaluronidase represents a potent strategy for investigating sentinel LNs., Graphical Abstract, Comprehensive analysis on lymphatic trafficking of liposomes with various physicochemical properties revealed that anionic 130-nm liposomes preferably retained in the lymph node at which they first reached. This retention allowed for detection of sentinel lymph node with cancer models. Moreover, extracellular matrix degradation by hyaluronidase improved detection sensitivity.

Blood-brain barrier (BBB)-permeable middle- or macromolecules (middle/macromolecules) have recently attracted significant attention as new drug delivery carriers into the human brain via receptor-mediated transcytosis (RMT). During the development process of such carriers, it is necessary to thoroughly evaluate their human BBB permeability levels. In such evaluations, our recently established human immortalized cell-based multicellular spheroidal BBB models (hiMCS-BBB models) have shown high potential. However, the specifics of those capabilities have yet to be elucidated. Therefore, in this study, we characterize the ability of the hiMCS-BBB models to evaluate RMT-mediated BBB penetration properties of middle/macromolecules. More specifically, we began by validating transferrin receptor (TfR)-mediated RMT functionalities using transferrin in the hiMCS-BBB models and then examined the BBB permeability levels of MEM189 antibodies (known BBB-permeable anti-TfR antibodies). The obtained results showed that, as with the case of transferrin, temperature-dependent uptake of MEM189 antibodies was observed in the hiMCS-BBB models, and the extent of that uptake increased in a time-dependent manner until reaching a plateau after around 2 h. To further expand the evaluation applicability of the models, we also examined the BBB permeability levels of the recently developed SLS cyclic peptide and observed that peptide uptake was also temperature-dependent. To summarize, our results show that the hiMCS-BBB models possess the ability to evaluate the RMT-mediated BBB-permeable properties of antibodies and peptides and thus have the potential to provide valuable tools for use in the exploration and identification of middle/macromolecules showing excellent BBB permeability levels, thereby contributing powerfully to the development of new drug delivery carriers for transporting drugs into the human brain.

The blood–brain barrier (BBB), which is comprised of brain capillary endothelial cells, plays a pivotal role in the transport of drugs from the blood to the brain. Therefore, an analysis of proteins in the endothelial cells, such as transporters and tight junction proteins, which contribute to BBB function, is important for the development of therapeutics for the treatment of brain diseases. However, gene transfection into the vascular endothelial cells of the BBB is fraught with difficulties, even in vitro. We report herein on the development of lipid nanoparticles (LNPs), in which mRNA is encapsulated in a nano-sized capsule composed of a pH-activated and reductive environment-responsive lipid-like material (ssPalm). We evaluated the efficiency of mRNA delivery into non-polarized human brain capillary endothelial cells, hCMEC/D3 cells. The ssPalm LNPs permitted marker genes (GFP) to be transferred into nearly 100% of the cells, with low toxicity in higher concentration. A proteomic analysis indicated that the ssPalm-LNP had less effect on global cell signaling pathways than a Lipofectamine MessengerMAX/GFP-encoding mRNA complex (LFN), a commercially available transfection reagent, even at higher mRNA concentrations.

Benzbromarone, a uricosuric drug, has the potential to cause serious hepatotoxicity. Several studies have shown the formation of reactive metabolites of benzbromarone and their association with hepatotoxicity in mice. However, it is unknown whether those reactive metabolites are generated in humans in vivo. In the present study, we firstly investigated the pharmacokinetic profiles of benzbromarone in chimeric TK-NOG mice transplanted with human hepatocytes (humanized-liver mice) and then investigated whether reactive metabolites could be generated. The area under the plasma concentration-time curve ratio of benzbromarone and its major metabolites (benzbromarone: 1'-hydroxy benzbromarone: 6-hydroxy benzbromarone) in humanized-liver mice was 1: 1.2: 0.7, which was similar to that reported in humans. In addition, glutathione conjugates and their further metabolites derived from the epoxidation of the benzofuran ring and 1',6-dihydroxylation of benzbromarone were detected in the livers, urine and plasma. Furthermore, their peak intensities in mass spectrometry showed markedly higher levels compared with those of TK-NOG mice. These results suggested that the metabolic profiles of benzbromarone in humanized-liver mice were similar to those in humans and that the reactive metabolites detected in humanized-liver mice could be generated and are associated with the benzbromarone-induced hepatotoxicity in humans.

Background: Emerging evidence suggests that 7-ketocholesterol (7-KC), one of the most abundant dietary oxysterols, causes inflammation and cardiovascular diseases. Here we show the deteriorating effects of dietary 7-KC on myocardial ischemia–reperfusion (IR) injury and detailed the molecular mechanisms.Methods and Results: A high-fat high-cholesterol diet containing 7-KC (7KWD) for 3 weeks increased the plasma 7-KC level compared with high-fat high-cholesterol diet in mice. In wild-type mice but not in CCR2-/- mice, dietary 7-KC increased the myocardial infarct size after IR. Flow cytometry revealed that the ratio of Ly-6Chigh inflammatory monocytes to total monocytes was increased in the 7KWD group. Unbiased RNA sequencing using murine primary macrophages revealed that 7-KC regulated the expression of transcripts related to inflammation and cholesterol biosynthesis. We further validated that in vitro, 7-KC induced endoplasmic reticulum stress, mitochondrial reactive oxygen species production, and nuclear factor-kappa B activation, which are associated with increased mRNA levels of proinflammatory cytokines. Administration of N-acetyl-L-cysteine or siRNA-mediated knockdown of PKR-like endoplasmic reticulum kinase or endoplasmic reticulum oxidase 1α suppressed the levels of 7-KC-induced inflammation.Conclusion: Dietary 7-KC exacerbates myocardial IR injury through monocyte/macrophage-mediated inflammation. Endoplasmic reticulum stress and oxidative stress are involved in the 7-KC-induced proinflammatory response in macrophages.

Lymphatic endothelial cells (LECs) that form lymphatic vessels play a pivotal role in immune regulation. It was recently reported that LECs suppress the antigen-dependent anti-tumor immunity in cancer tissues. Thus, regulating the function of LECs is a promising strategy for cancer therapy. The objective of this study was to develop a method for the selective delivery of small interfering RNA (siRNA) to LECs. For this purpose, the siRNA was formulated into nanoparticles (LNPs) to prevent them from being degraded in body fluids and to facilitate their penetration of the cell membrane. A breakthrough technology for achieving this is ONPATTRO®, a world's first siRNA drug. Since LNPs are taken up by hepatocytes relatively well via low-density lipoprotein receptors, most of the LNP systems that have been developed so far target hepatocytes. In this study, we report on the development of a new method for the rapid and convenient method for modifying LNPs with antibodies using the CLick reaction on the Interface of the nanoParticle (CLIP). The CLIP approach was faster and more versatile than the conventional method using amide coupling. As a demonstration, we report on the LEC-targeted siRNA delivery by using antibody-modified LNPs both in vitro and in vivo. The method used for the modification of LNPs is highly promising and has the potential for expanding the LNP-based delivery of nucleic acids in the future.

Metastasis of cancer cells to lymph nodes (LN) is a common modality of metastasis in clinical settings, but the mechanisms involved in lymphatic metastasis remain unclear compared to hematogenous metastasis to bones and the brain. To elucidate the molecular mechanisms responsible for melanoma LN metastasis, we first generated LN metastasis-prone melanoma cells (C8161F2) by the sequential in vivo transplantation of parental melanoma cells (C8161F0). Although the in vitro/in vivo proliferative potential of these melanoma cells were similar, the metastatic potential of the C8161F2 for LNs was significantly enhanced. We then conducted a proteomics analysis to identify the proteins and pathways that contribute to LN metastasis. We identified six proteins (three: up-regulated and three: down-regulated) whose expressions were statistically significantly different by more than 2-fold in the two cell groups. Some of these genes are responsible for the activation of the transforming growth factor-β (TGF-β)-related pathway, a well-known inducer of epithelial-mesenchymal transition (EMT). In addition, a gene ontology analysis revealed that the enhanced cell-cell adhesion appears to be involved in lymphatic metastasis. In conclusion, we established highly lymphatic metastatic melanoma cells, which would be valuable for studies of the molecular mechanisms responsible for lymphatic metastasis.

The GALA peptide (WEAALAEALAEALAEHLAEALAEALEALAA) was originally designed to induce the destabilization of endosomal membranes based on its ability to undergo a pH-dependent conformational change from a random coil to an α-helix. We recently found that liposomes modified with GALA peptide (GALA-LPs) extensively accumulate in lung endothelial cells (ECs) after intravenous injection. However, the uptake mechanism of GALA-LPs and their ability to reach alveolar epithelium was unclear. We report herein that GALA-LPs are internalized into ECs via a clathrin-mediated pathway. Surprisingly, GALA-LPs had the ability to pass lung ECs and reach other cells through transcytosis. GALA-LPs were taken up by >70% of lung ECs, while they also accumulated in ~30% of type I alveolar epithelium (ATI). GALA-modified gold nanoparticles were detected in ECs, in the basement membrane and in other cells such as ATI, type II alveolar epithelium (ATII) and alveolar macrophages. Consistent with this result, a significant gene knockdown was achieved in lung epithelium cells using GALA-LPs encapsulating anti-podoplanin siRNA. This indicates that GALA-LPs can be used as a carrier for delivering macromolecules to parenchymal as well as to endothelial cells in the lung. Although caveolae are commonly linked to the transendothelial transport of proteins and antibodies, our data indicate that clathrin-mediated endocytosis might also participate in the transcytosis process.

While the use of in vitro-transcribed mRNA (IVT-mRNA) in therapeutics is a rapidly expanding area, the transfection of the exogenous IVT-mRNA is accompanied by a risk of immune activation. This immunological defense mechanism suppresses cellular translation process and can reduce transfection efficiency to a considerable extent. In the present study, we investigated the in vitro effects of Integrated Stress Response Inhibitor (ISRIB), and dexamethasone, a steroidal anti-inflammatory drug, on the transfection activity of a lipid nanoparticle (LNP) that was composed of ionizable lipids and IVT-mRNA. In the case of transfection to mouse embryonic fibroblast (MEF) cells, ISRIB mainly enhanced the transfection activity at an early stage of transfection (0-6 h). In contrast, dexamethasone caused an increase in transfection activity at intermediate-late stages of transfection (4-48 h). We also investigated the in vivo effects of dexamethasone using an LNP on that the IVT-mRNA and lipid-conjugated dexamethasone (Dex-Pal) were co-loaded. The intravenous administration of the LNP successfully enhanced the protein expression in a mouse liver by up to 6.6-fold. Collectively, the co-delivery of an anti-inflammatory drug is a promising approach for enhancing transfection efficiency of IVT-mRNA.

In vitro blood-brain barrier (BBB) models are essential research tools for use in developing brain-targeted drugs and understanding the physiological and pathophysiological functions of the BBB. To develop BBB models with better functionalities, three-dimensional (3D) culture methods have gained significant attention as a promising approach. In this study, we report on the development of a human conditionally immortalized cell-based multicellular spheroidal BBB (hiMCS-BBB) model. After being seeded into non-attachment culture wells, HASTR/ci35 (astrocytes) and HBPC/ci37 cells (brain pericytes) self-assemble to form a spheroid core that is then covered with an outer monolayer of HBMEC/ci18 cells (brain microvascular endothelial cells). The results of immunocytochemistry showed the protein expression of several cellular junction and BBB-enriched transporter genes in HBMEC/ci18 cells of the spheroid model. The permeability assays showed that the hiMCS-BBB model exhibited barrier functions against the penetration of dextran (5 and 70 kDa) and rhodamine123 (a P-glycoprotein substrate) into the core. On the other hand, facilitation of 2-(N-[7-nitrobenz-2-oxa-1,3-diazol-4-yl]amino)-2-deoxyglucose (2-NBDG; a fluorescent glucose analog) uptake was observed in the hiMCS-BBB model. Furthermore, tumor necrosis factor-alpha treatment elicited an inflammatory response in HBMEC/ci18 cells, thereby suggesting that BBB inflammation can be recapitulated in the hiMCS-BBB model. To summarize, we have developed an hiMCS-BBB model that possesses fundamental BBB properties, which can be expected to provide a useful and highly accessible experimental platform for accelerating various BBB studies.

We herein report 2 cases of gastric cancer treated by S-1 and oxaliplatin combination therapy before later undergoing gastrectomy. The pathological results of both cases demonstrated complete response. Case 1 had a giant tumor which was suspected to have invaded the pancreas. Case 2 was associated with extensive lymph node metastasis. Based on the findings of these 2 cases, preoperative chemotherapy with S-1 and oxaliplatin for advanced gastric cancer shows sufficient efficacy.

It is important to predict drug-drug interactions via inhibition of intestinal cytochrome P450 3A (CYP3A) which is a determinant of bioavailability of orally administered CYP3A substrates. However, inhibitory effects of macrolide antibiotics on CYP3A-mediated metabolism are not entirely identical between humans and rodents.We investigated the effects of macrolide antibiotics, clarithromycin and erythromycin, on in vitro and in vivo metabolism of triazolam, a CYP3A substrate, in CYP3A-humanised mice generated by using a mouse artificial chromosome vector carrying a human CYP3A gene.Metabolic activities of triazolam were inhibited by macrolide antibiotics in liver and intestine microsomes of CYP3A-humanised mice.The area under the plasma concentration-time curve ratios of 4-hydroxytriazolam to triazolam after oral dosing of triazolam were significantly decreased by multiple administration of macrolide antibiotics. The plasma concentrations ratios of α-hydroxytriazolam and 4-hydroxytriazolam to triazolam in portal blood were significantly decreased by multiple administration of clarithromycin in CYP3A-humanised mice.These results suggest that intestinal CYP3A activity was inhibited by macrolide antibiotics in CYP3A-humanised mice in vitro and in vivo. The plasma concentrations of triazolam and its metabolites in the portal blood of CYP3A-humanised mice would be useful for direct evaluation of intestinal CYP3A-mediated drug-drug interactions. It is important to predict drug-drug interactions via inhibition of intestinal cytochrome P450 3A (CYP3A) which is a determinant of bioavailability of orally administered CYP3A substrates. However, inhibitory effects of macrolide antibiotics on CYP3A-mediated metabolism are not entirely identical between humans and rodents. We investigated the effects of macrolide antibiotics, clarithromycin and erythromycin, on in vitro and in vivo metabolism of triazolam, a CYP3A substrate, in CYP3A-humanised mice generated by using a mouse artificial chromosome vector carrying a human CYP3A gene. Metabolic activities of triazolam were inhibited by macrolide antibiotics in liver and intestine microsomes of CYP3A-humanised mice. The area under the plasma concentration-time curve ratios of 4-hydroxytriazolam to triazolam after oral dosing of triazolam were significantly decreased by multiple administration of macrolide antibiotics. The plasma concentrations ratios of α-hydroxytriazolam and 4-hydroxytriazolam to triazolam in portal blood were significantly decreased by multiple administration of clarithromycin in CYP3A-humanised mice. These results suggest that intestinal CYP3A activity was inhibited by macrolide antibiotics in CYP3A-humanised mice in vitro and in vivo. The plasma concentrations of triazolam and its metabolites in the portal blood of CYP3A-humanised mice would be useful for direct evaluation of intestinal CYP3A-mediated drug-drug interactions.

Gene and nucleic acid-based medication is an ultimate strategy in the field of personalized medicine. A gene or short interference RNA (siRNA) molecule needs to be delivered to the appropriate organelle (i.e., nucleus and cytoplasm, respectively). We recently focused on improving the intrinsic activity of my original material (ssPalm) in terms of endosomal/lysosomal membrane destabilization activity by chemically modifying the tertiary amine structure. In parallel, I have been expanding the range of applications of ssPalms. The first application is a DNA or RNA vaccine. My crucial finding is that the vitamin E-scaffold ssPalm (ssPalmE) is highly immune-stimulative when combined with DNA. Thereafter, I redesigned the hydrophobic scaffold structure, and found that an oleic acid-scaffold ssPalm (ssPalmO) can confer anti-inflammatory characteristics. Based on this result, I further upgraded the ssPalmO, by inserting a newly designed linker with self-degradable properties.

The treatment of sensorineural hearing loss (SNHL) may be achieved via the application of a cochlear implant (CI) that allows the electrical stimulation of spiral ganglion neurons (SGNs). Nevertheless, the efficacy of CIs is limited by the degeneration of SGNs following SNHL. Although the application of exogenous neurotrophic factors has been reported to decrease SGN degeneration, non-invasive targeted drug delivery systems are required to achieve effective results. In this study, an SS-cleavable proton-activated lipid-like material [ssPalm; a neutral lipid nanoparticle (LNP)], was loaded with mRNA, and the efficacy of this material as a delivery system was investigated. Our results showed that LNPssPalm carrying brain-derived neurotrophic factor (BDNF) mRNA was suitable for the treatment of inner ear diseases, preventing the degeneration of SGNs. In conclusion, this modern nanotechnology-based bioconjugation system, LNPssPalm, is a potential non-invasive targeted therapy allowing the delivering biomaterials to specific structures within the inner ear for the treatment of SHNL.

A 71-year-old male presented with abdominal distension and fever to our hospital. Abdominal CT revealed a huge tumor in abdomen, and non-curative surgery was performed. Peritoneal dissemination was widespread and the tumor invaded the bladder and sigmoid-colon mesenterium. Two months after the initial surgery, CT showed liver metastasis, and oral administration of imatinib mesylate was started. The peritoneal dissemination and liver metastasis showed a decrease, and this was well controlled for 45 months without severe side effects. Abdominal CT revealed peritoneal dissemination in the ileocecum after 43 months since the administration of imatinib. Therefore, sunitinib treatment was initiated. After 3 months of sunitinib administration, the tumor perforated. Emergency operation was performed to resect the ileocecum, and sunitinib was continued for 1 year. In GIST with liver metastasis and peritoneal dissemination, repeated surgical resection combined with chemotherapy is important to improve the patient's survival.

In vivo pharmacokinetics (PK) studies using mice and monkeys are the main approaches for evaluating and predicting the PK of antibodies, and there is a strong demand for methods that do not require animal experiments. In this work, we focused on quantitatively predicting the nonlinear PK of an antibody based on cell-based assays. An anti-mouse Fc gamma receptor IIB antibody was used as a model antibody. To determine the PK parameters related to nonspecific elimination in vivo, the plasma concentration profile at 100 mg/kg, at which target-specific clearance is saturated, was analyzed by a 2-compartment model. To estimate the parameters related to target-specific elimination, the Michaelis–Menten constant (Km) and the maximum elimination rate (Vmax) were determined by an uptake assay using Chinese hamster ovary (CHO) cells expressing the target receptor. Finally, the integration of all of these parameters permitted the PK to be predicted at doses ranging from 1 to 100 mg/kg regardless of whether target-specific clearance was saturated or nonsaturated. The findings presented herein show that in vitro assays using target-expressing cells are useful tools for obtaining PK parameters and predicting PK profiles and, in some cases, eliminate the need for in vivo PK studies using experimental animals.

Messenger RNA and small interfering RNA are attractive modalities for curing diseases by complementation or knock-down of proteins. For success of these RNAs, a drug delivery system (DDS) is required to control a pharmacokinetics, to enhance cellular uptake, to overcome biological membranes, and to release the cargo into the cytoplasm. Based on past research, developing nanoparticles that are neutrally charged have been the mainstream of their development. Also, the materials are further mounted with pH- and/or reducing environment-responsive units. In this review, we summarize progress made in the molecular design of these materials. We also focus on the importance of the hydrophobic scaffold for tissue/cell targeting, intracellular trafficking, and immune responses. As a practical example, the design concept of the SS-cleavable and pH-activated lipid-like material (ssPalm) and subsequent molecular modification tailored to the RNA-based medical application is discussed.

Currently, chemotherapy against unresectable advanced gastric cancer is progressing with the development new drugs and due to results of several clinical trials. Here, we reported a case of long-term survival of gastric cancer with multiple liver and lymph node metastases. A 68-year-old man was diagnosed with gastric cancer and Virchow lymph node, para-aortic lymph node, and multiple liver metastases at another hospital. He was referred to our hospital from Yamashita Naika Syokakika. We administrated 4 courses of S-1 plus CDDP. The main tumor and all metastatic lesions were significantly reduced. Subsequently, total gastrectomy, partial liver resection, and left neck and para-aortic lymph node resection(conversion surgery)were performed. The cancer cell was remnant at the main tumor and para-gastric lymph node. No cancer cells were detected in another lesion(R0 resection). Postoperatively, only S-1 was administered. However, 28 months after undergoing gastrectomy, liver metastasis occurred. Therefore, S-1 plus oxaliplatin, paclitaxel plus ramucirumab, and CPT-11 plus CDDP were administered. Liver metastases again increased and decreased, respectively. However, 46 months after gastrectomy, liver metastasis recurred and nivolumab was administered. Subsequently, liver metastases disappeared. At 55 months after gastrectomy, rectal resection was performed against rectal cancer and partial liver resection against liver metastases. Cancer cells were not detected in the resected specimens.

DNA vaccinations are promising strategies for treating diseases that require cellular immunity (i.e., cancer and protozoan infection). Here, we report on the use of a liposomal nanocarrier (lipid nanoparticles (LNPs)) composed of an SS-cleavable and pH-activated lipidlike material (ssPalm) as an in vivo DNA vaccine. After subcutaneous administration, the LNPs containing an ssPalmE, an ssPalm with vitamin E scaffolds, elicited a higher gene expression activity in comparison with the other LNPs composed of the ssPalms with different hydrophobic scaffolds. Immunization with the ssPalmE-LNPs encapsulating plasmid DNA that encodes ovalbumin (OVA, a model tumor antigen) or profilin (TgPF, a potent antigen of Toxoplasma gondii) induced substantial antitumor or antiprotozoan effects, respectively. Flow cytometry analysis of the cells that had taken up the LNPs in draining lymph nodes (dLNs) showed that the ssPalmE-LNPs were largely taken up by macrophages and a small number of dendritic cells. We found that the transient deletion of CD169+ macrophages, a subpopulation of macrophages that play a key role in cancer immunity, unexpectedly enhanced the activity of the DNA vaccine. These data suggest that the ssPalmE-LNPs are effective DNA vaccine carriers, and a strategy for avoiding their being trapped by CD169+ macrophages will be a promising approach for developing next-generation DNA vaccines.

Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3) has been identified as a cancer-specific transcript in various solid cancers, including colorectal cancer. Given its excellent cancer-specific expression profile, we hypothesized that Ct-OATP1B3 could represent a promising target for cancer-specific expression of the suicide gene, herpes simplex virus 1 thymidine kinase (HSV-tk), via a spliceosome-mediated RNA trans-splicing (SMaRT) approach. SMaRT technology is used to recombine two RNA molecules to generate a chimeric transcript. In this study, we engineered an RNA trans-splicing molecule carrying a translation-defective HSV-tk sequence (RTM44), which was capable of inducing its own trans-splicing to the desired Ct-OATP1B3 pre-mRNA target. RTM44 expression in LS180 cells resulted in generation of Ct-OATP1B3/HSV-tk fusion mRNA. A functional translation start site contributed by the target pre-mRNA restored HSV-tk protein expression, rendering LS180 cells sensitive to ganciclovir treatment in vitro and in xenografted mice. The observed effects are ascribed to accurate and efficient trans-splicing, as they were absent in cells carrying a splicing-deficient mutant of RTM44. Collectively, our data highlights Ct-OATP1B3 as an ideal target for the HSV-tk SMaRT suicide system, which opens up new translational avenues for Ct-OATP1B3-targeted cancer therapy.

Non-viral vectors are considered to be an attractive approach for gene delivery, since an artificial material is less immunogenic and oncogenic compared to a viral vector. We previously reported on the hepatic delivery of plasmid DNA (pDNA) by using lipid-like material (an SS-cleavable and pH-activated lipid-like material: ssPalm) which mounts two hydrophobic scaffolds, proton-accepting motifs (tertiary amines), and a cleavable unit (disulfide bonding). In the present study, we report on an advanced hepatic gene delivery system that uses a new type of ssPalm derivative: ssPalmE-Paz4-C2. The hepatic transgene expression of the intravenously administrated lipid nanoparticle (LNP) that was formed with the ssPalmE-Paz4-C2 (LNPssPalmE-Paz4-C2) was significantly higher than that of conventional LNPs formed with a myristic acid-scaffold ssPalm (LNPssPalmM). However, the LNPssPalmE-Paz4-C2 particle induced a severe innate immune response that involved the production of the pro-inflammatory cytokines (IL-6 and TNFα), intracellular DNA sensor-related cytokine (IL-1β) and interferon (IFNβ), even when a pDNA free from CpG-motifs was encapsulated. The production of the pro-inflammatory cytokines and the DNA sensor-related cytokines is attributed to the combination of vitamin E scaffolds and encapsulated pDNA. The depletion of macrophages by chlodronate-encapsulating liposomes dramatically reduced inflammatory gene expression. Based on the above findings, we conclude that the use of a certain type of non-viral carrier that shows a robust gene expression activity is attended by a risk of eliciting an innate immune response. When a highly hydrophobic derivative of dexamethasone, an anti-inflammatory glucocorticoid compound, was co-loaded to the particle, this inflammatory response was relieved, and gene expression efficiency was enhanced. It is thus concluded that the co-delivery of dexamethasone and pDNA is a promising approach for reducing these risks.

Cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3) mRNA is a variant isoform of the liver-type OATP1B3. Because Ct-OATP1B3 mRNA shows an excellent cancer-specific expression profile in colorectal cancer (CRC), and that its expression levels are associated with CRC prognosis, it holds the potential to become a useful CRC detection and diagnosis biomarker. While the potential is currently justified only at the tissue level, if existence of Ct-OATP1B3 mRNA in CRC-derived extracellular vesicles (EVs) is validated, the findings could enhance its translational potential as a CRC detection and diagnosis biomarker. Therefore, this study aims at proving that Ct-OATP1B3 mRNA exists in CRC-derived EVs, and can be detected using serum specimens. To examine the possibility of Ct-OATP1B3 mRNA being existed in extracellular milieu, we isolated EVs from the human CRC (HCT116, HT-29, and SW480) cell lines, and prepared their cDNAs. The RT-PCR results showed that Ct-OATP1B3 mRNA was clearly present in EVs derived from the human CRC cell lines. Then, in order to further explore the possibility that Ct-OATP1B3 mRNA in CRC-derived EVs can be detected in serum, we isolated serum EVs derived from human CRC xenograft mice, and then performed RT-PCR. The results showed that Ct-OATP1B3 mRNA could be found in all serum EV and CRC tissue samples of the mice examined. Collectively, our findings, which show that Ct-OATP1B3 mRNA exists in EVs and can be detected in (at least) mouse serum, strengthen the potential use of Ct-OATP1B3 mRNA as a serum-based CRC biomarker.

While pericytes wrap around microvascular endothelial cells throughout the human body, their highest coverage rate is found in the brain. Brain pericytes actively contribute to various brain functions, including the development and stabilization of the blood-brain barrier (BBB), tissue regeneration, and brain inflammation. Accordingly, detailed characterization of the functional nature of brain pericytes is important for understanding the mechanistic basis of brain physiology and pathophysiology. Herein, we report on the development of a new human brain pericyte cell line, hereafter referred to as the human brain pericyte/conditionally immortalized clone 37 (HBPC/ci37). Developed via the cell conditionally immortalization method, these cells exhibited excellent proliferative ability at 33 °C. However, when cultured at 37 °C, HBPC/ci37 cells showed a differentiated phenotype that was marked by morphological alterations and increases in several pericyte-enriched marker mRNA levels, such as platelet-derived growth factor receptor β. It was also found that HBPC/ci37 cells possessed the facilitative ability of in vitro BBB formation and differentiation into a neuronal lineage. Furthermore, HBPC/ci37 cells exhibited the typical "reactive" features of brain pericytes in response to pro-inflammatory cytokines. To summarize, our results clearly demonstrate that HBPC/ci37 cells possess the ability to perform several key brain pericyte functions while also showing the capacity for extensive and continuous proliferation. Based on these findings, it can be expected that, as a unique human brain pericyte model, HBPC/ci37 cells have the potential to contribute to significant advances in the understanding of human brain pericyte physiology and pathophysiology.

Pregnane X receptor (PXR) is localized in the cytoplasm of liver cells, whereas it is localized in the nucleus of monolayer-cultured HepG2 cells. Since cultured cells are affected by the microenvironment in which they are grown, we studied the effect of three-dimensional (3D) culture on the localization of PXR in HepG2 cells using the hanging drop method. The results showed that PXR was retained in the cytoplasm of HepG2 cells and other human hepatocarcinoma cell lines (FLC5, FLC7 and Huh7) when they were cultured by the hanging drop method. Treatment with rifampicin, a ligand of PXR, translocated PXR from the cytoplasm to nucleus and increased expression levels of CYP3A4 mRNA in HepG2 cells cultured by the hanging drop method. These findings suggest that 3D culture is a key factor determining the intracellular localization of PXR in human hepatocarcinoma cells and that PXR that becomes retained in the cytoplasm of HepG2 cells with 3D culture has functions of nuclear translocation and regulation of target genes in response to human PXR ligands. Three-dimensionally cultured hepatocarcinoma cells would be a useful tool to evaluate induction potency of drug candidates and also to study mechanisms of nuclear translocation of PXR by human PXR ligands.

Aim: We aimed to clarify diagnostic and prognostic biomarker potentials of cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3) mRNA in colorectal cancer (CRC) patients. Patients & methods: Ct-OATP1B3 mRNA levels in 97 CRC and adjacent normal colon tissues were measured by real-time PCR. The receiver operating characteristic curve analysis and the Kaplan–Meier curve analysis were performed to characterize its biomarker potentials. Results: Ct-OATP1B3 mRNA showed noticeable diagnostic power (the area under the receiver operating characteristic = 0.91) in the CRC patients. Additionally, the higher/lower mRNA expression was clearly associated with better/poorer overall survival in the CRC patients (p < 0.05). Conclusion: Ct-OATP1B3 mRNA has the potential to be a tissue-based biomarker for definitive diagnosis and prognostic stratification in CRC.

Lipids functionalized with tertiary amines (ionizable lipids) for a pH-dependent positive charge have been developed extensively as a carrier material for delivering nucleic acids. We previously developed an SS-cleavable proton-activated lipid-like material (ssPalm) as a component of a functionalized lipid envelope structure of a nanoparticle that encapsulated plasmid DNA and short interfering RNA. In this study, we report on the unique characteristics of such an ionizable lipid: the formation of a nano-sized emulsion (ave. 40nm) via pH-triggered self-emulsification in the absence of a cargo (nucleic acids). The particle has a neutral charge at physiological pH and is stabilized by helper lipids and polyethyleneglycol (PEG)-conjugated lipids. The generalized polarization of 6-dodecanoyl-2-dimethylaminonaphthalene (Laurdan), which indicates the surface polarity caused by the invasion of water onto the surface, changes dynamically in response to pH and temperature, while the fluidity of the intra-particle compartment, as measured by the fluorescence anisotropy of 1,6-Diphenyl-1,3,5-hexatriene (DPH), is not affected. Even when the particle contains a high density of PEG on the surface, it shows a high fusogenecity to negatively charged liposomes in response to an acidic pH to a higher degree than a conventional cationic lipid. These characteristics suggest that the ssPalm particle possesses unique properties for delivering lipophilic drugs across the biomembrane.

Brain microvascular endothelial cells (BMEC), together with astrocytes and pericytes, form the blood-brain barrier (BBB) that strictly restricts drug penetration into the brain. Therefore, in central nervous system drug development, the establishment of an in vitro human BBB model for use in studies estimating the in vivo human BBB permeability of drug candidates has long been awaited. The current study developed and characterized a human immortalized cell-based BBB triculture model, termed the "hiBBB" model. To set up the hiBBB model, human immortalized BMEC (HBMEC/ci18) were cocultured with human immortalized astrocytes (HASTR/ci35) and brain pericytes (HBPC/ci37) in a transwell system. The trans-endothelial electrical resistance of the hiBBB model was 134.4 ± 5.5 (Ω × cm2), and the efflux ratios of rhodamine123 and dantrolene were 1.72 ± 0.11 and 1.72 ± 0.45, respectively, suggesting that the hiBBB model possesses essential cellular junction and efflux transporter functions. In BBB permeability assays, the mean value of the permeability coefficients (Pe) of BBB permeable compounds (propranolol, pyrilamine, memantine, and diphenhydramine) was 960 × 10-6 cm/s, which was clearly distinguishable from that of BBB nonpermeable compounds (sodium fluorescein and Lucifer yellow, 18 × 10-6 cm/s). Collectively, this study successfully developed the hiBBB model, which exhibits essential BBB functionality. Taking into consideration the high availability of the immortalized cells used in the hiBBB model, our results are expected to become an initial step toward the establishment of a useful human BBB model to investigate drug penetration into the human brain.

While the use of in vitro-transcribed mRNA (IVT-mRNA) in therapeutics is a rapidly expanding area, the transfection of the exogenous IVT-mRNA is accompanied by a risk of immune activation. This immunological defense mechanism suppresses cellular translation process and can reduce transfection efficiency to a considerable extent. In the present study, we investigated the in vitro effects of Integrated Stress Response Inhibitor (ISRIB), and dexamethasone, a steroidal anti-inflammatory drug, on the transfection activity of a lipid nanoparticle (LNP) that was composed of ionizable lipids and IVT-mRNA. In the case of transfection to mouse embryonic fibroblast (MEF) cells, ISRIB mainly enhanced the transfection activity at an early stage of transfection (0-6 h). In contrast, dexamethasone caused an increase in transfection activity at intermediate-late stages of transfection (4-48 h). We also investigated the in vivo effects of dexamethasone using an LNP on that the IVT-mRNA and lipid-conjugated dexamethasone (Dex-Pal) were co-loaded. The intravenous administration of the LNP successfully enhanced the protein expression in a mouse liver by up to 6.6-fold. Collectively, the co-delivery of an anti-inflammatory drug is a promising approach for enhancing transfection efficiency of IVT-mRNA.

Taking advantage of the enhanced permeation and retention (EPR) effect is a promising approach for delivering macromolecules or nanoparticles to tumors. Recent studies revealed that this strategy is also applicable for targeting other pathological lesions (i.e. inflammatory disease). In the present study, we report the optimal size of a nanoparticle for allowing the higher accumulation of a particle in an inflammatory lesion using a dextran sulfate sodium (DSS)-induced colitis model. As a nanoparticle platform, we utilized a SS-cleavable and pH-activated lipid-like material (ssPalm), that can be used to produce particles in a variety of sizes ranging from 50 nm to 180 nm while using the same lipid composition. In healthy mice, particle accumulation remained low regardless of size. In contrast, the accumulation in inflammatory colon tissue was enhanced depending on the progress of the inflammation. In this situation, the apparent uptake clearance accumulation of a mid-sized particle (113 nm on average) was higher than that for smaller and larger (54 nm and 183 nm in average, respectively) ones. Therefore, controlling particle size is an important parameter for the extensive targeting of inflammatory lesion.

Systems for delivering nucleic acids are now fundamental technologies for realizing personalized medicine. Among the various nucleic acid delivery systems that are currently available, lipid-nanoparticles (LNPs) that contain short interfering RNA (siRNA) have been extensively investigated for clinical applications. LNPs are generally prepared by an alcohol dilution method. In this method, it is necessary to remove the alcohol and then concentrate the LNP sample before they can be used. In this study, we report on the development of an "alcohol dilution-lyophilization method" for preparing siRNA-encapsulating LNPs. This method involves the use of a freeze-drying (lyophilization) method to remove the residual alcohol and to simultaneously concentrate the preparation. At first, the compositions of cryoprotectants and polyethylene glycol (PEG)-lipids that were used were optimized from the point of view of particle stabilization. A combination of sucrose and 1-(monomethoxy polyethyleneglycol5000)-2,3-dimyristoylglycerol (DMG-PEG5000) was found to have the most efficient cryoprotective activity for the LNPs. The knockdown efficiency of the LNP prepared by the alcohol dilution-lyophilization method was comparable to that of an LNP prepared by the conventional ultrafiltration method.