Polymers from Plant Oils Linked by Siloxane Bonds for Programmed Depolymerization.

The increased production of plastics is leading to the accumulation of plastic waste and depletion of limited fossil fuel resources. In this context, we report a strategy to create polymers that can undergo controlled depolymerization by linking renewable feedstocks with siloxane bonds. α,ω-Diesters and α,ω-diols containing siloxane bonds were synthesized from an alkenoic ester derived from castor oil and then polymerized with varied monomers, including related biobased monomers. In addition, cyclic monomers derived from this alkenoic ester and hydrosiloxanes were prepared and cyclized to form a 26-membered macrolactone containing a siloxane unit. Sequential ring-opening polymerization of this macrolactone and lactide afforded an ABA triblock copolymer. This set of polymers containing siloxanes underwent programmed depolymerization into monomers in protic solvents or with hexamethyldisiloxane and an acid catalyst. Monomers afforded by the depolymerization of polyesters containing siloxane linkages were repolymerized to demonstrate circularity in select polymers. Evaluation of the environmental stability of these polymers toward enzymatic degradation showed that they undergo enzymatic hydrolysis by a fungal cutinase from Fusarium solani. Evaluation of soil microbial metabolism of monomers selectively labeled with 13C revealed differential metabolism of the main chain and side chain organic groups by soil microbes.

Single targeting of MET in EGFR-mutated and MET-amplified non-small cell lung cancer.

BACKGROUND: In EGFR-mutant and MET-amplified lung cancer resistant to EGFR inhibitors, double blockade of EGFR and MET is considered as a reasonable strategy despite increasing toxicity. This study evaluated the single MET inhibition in these specific tumours. METHODS: We investigated the efficacy of a single MET inhibitor in EGFR-mutant, MET-amplified lung cancer cells (HCC827GR) and the matched clinical cases and patient-derived cells. Acquired resistance mechanisms to single MET inhibitor were further explored. RESULTS: Single MET inhibitor sufficiently inhibited the EGFR downstream signalling and proliferation in the HCC827GR cells. The MET-inhibitor-sensitive clones had similar EGFR mutation allele frequency as the MET-inhibitor-resistant clones. The patients with EGFR-mutant, MET-amplified lung cancer resistant to EGFR inhibitors showed definite response to single MET inhibitor but the response duration was not durable. The MET gene copy number in their plasma circulating tumour DNA was significantly decreased during the treatment and was not re-increased after progression. In the cells resistant to single MET inhibitor, the EGFR pathway was reactivated, and gefitinib alone successfully suppressed their growth. CONCLUSIONS: Single MET inhibition produced a short-lived response in EGFR-mutant and MET-amplified lung cancer. A further study of a novel combination therapy schedule is needed to achieve long-lasting efficacy and less toxicity.

Live-cell screening platform using human-induced pluripotent stem cells expressing fluorescence-tagged cytochrome P450 1A1.

Human-induced pluripotent stem cells (hiPSCs) are invaluable sources for drug screening and toxicity tests because of their differentiation potential and proliferative capacity. Recently, the CRISPR-Cas9-mediated homologous recombination system has enabled reporter knock-ins at desired loci in hiPSCs, and here, we generated a hiPSC reporter line expressing mCherry-tagged cytochrome P450 1A1 (CYP1A1), which can be utilized to screen for the modulators of aryl hydrocarbon receptor (AHR) in live cells. CYP1A1-mCherry hiPSCs exhibited typical characteristics of pluripotent stem cells such as marker expression, differentiation potential, and normal karyotype. After differentiation into hepatocyte-like cells (HLCs), CYP1A1-mCherry fusion protein was expressed and localized at the endoplasmic reticulum, and induced by AHR agonists. We obtained 23 hits modulating CYP1A1 expression from high-content screening with 241 hepatotoxicity chemicals and nuclear receptor ligands, and identified three upregulating chemicals and two downregulating compounds. Responses of hiPSC-HLCs against an AHR agonist were more similar to human primary hepatocytes than of HepG2 hepatocellular carcinoma cells. This platform has the advantages of live-cell screening without sacrificing cells (unlike previously available CYP1A1 reporter cell lines), as well as an indefinite supply of cells, and can be utilized in a wide range of screening related to AHR- and CYP1A1-associated diseases in desired cell types.

Spectroscopy and excited state dynamics of nearly infinite polyenes.

Steady-state and transient absorption spectra with <50 fs time resolution were obtained for two conjugated polymers, both with ≈200 conjugated double bonds (N), constrained in planar, stable, polyene frameworks. Solutions of the polymers exhibit the same S2 → S1 → S* → S0 decay pathway observed for the N = 11-19 polyene oligomers and for zeaxanthin homologues with N = 11-23. Comparisons with the excited state dynamics of polydiactylene and a much longer, more disordered polyene polymer (poly(DEDPM)) show that the S2, S1, and S* lifetimes of the four polymers are almost identical. The S* signals in the polymers are assigned to absorption from vibrationally excited ground states. In spite of significant heterogeneities and variations in conjugation lengths in these long polyenes, their S0 → S2 absorptions are vibronically-resolved in room temperature solutions with electronic origins at ≈600 nm. The limiting wavelength for the S0 → S2 transitions is consistent with the persistence of bond length alternation in the electronic ground states and a HOMO-LUMO band gap in polyenes with N ≈ 200. The coincidence of the well-resolved S0 → S2 electronic origins and the convergence of the excited state lifetimes in the four polymers point to a common, "nearly infinite" polyene limit.

The effect of combination therapy on critical-size bone defects using non-activated platelet-rich plasma and adipose-derived stem cells.

PURPOSE: Non-activated platelet-rich plasma (nPRP) slowly releases growth factors that induce bone regeneration. Adipose tissue-derived stem cells (ASCs) are also known to induce osteoblast differentiation. In this study, we investigated the combined effect of nPRP and ASC treatment compared with single therapy on bone regeneration. METHODS: Thirty New Zealand white rabbits with 15 × 15 mm2 calvarial defects were randomly divided into four treatment groups: control, nPRP, ASC, or nPRP + ASC groups. For treatment, rabbits received a collagen sponge (Gelfoam®) saturated with 1 ml normal saline (controls), 1 ml non-activated PRP (nPRP group), 2 × 106 ASCs (ASCs group), or 2 × 106 ASCs plus l ml nPRP (nPRP + ASCs group). After 16 weeks, bone volume and new bone surface area were measured, using three-dimensional computed tomography and digital photography. Bone regeneration was also histologically analyzed. RESULTS: Bone surface area in the nPRP group was significantly higher than both the control and ASC groups (p < 0.001 and p < 0.01, respectively). The percentage of regenerated bone surface area in the nPRP + ASC group was also significantly higher than the corresponding ratios in the control group (p < 0.001). The volume of new bone in the nPRP group was increased compared to the controls (p < 0.05). CONCLUSION: Our results demonstrate that slow-releasing growth factors from nPRP did not influence ASC activation in this model of bone healing. PRP activation is important for the success of combination therapy using nPRP and ASCs.

Sustained Release of Decoy Wnt Receptor (sLRP6E1E2)-Expressing Adenovirus Using Gel-Encapsulation for Scar Remodeling in Pig Model.

An adenoviral vector (Ad) expressing a Wnt decoy receptor (sLRP6E1E2) is known to induce an anti-fibrotic effect by inhibiting Wnt signaling. We evaluated its effects in vivo using pig models and attempted to introduce an alginate gel-matrix system to prolong the effect of the Ad. Transduction efficiency as to the biological activity of Ad in different forms was evaluated. Then, 50 days after the formation of full-thickness skin defects on the backs of Yorkshire pigs, scars were treated with each form of Ad. Therapeutic efficacy and various factors influencing scar formation and collagen rearrangement were analyzed. Inflammatory cell infiltration within the scar tissues was also evaluated. Decoy Wnt receptor (sLRP6E1E2)-expressing adenovirus treatment improved scar quality in a pig model. Loading this construct in alginate gel allows sustained virus release into local tissues and prolongs Ad activity, thus maintaining its therapeutic effect longer in vivo.

Scaffold Free Bone Regeneration Using Platelet-Rich Fibrin in Calvarial Defect Model.

Bone regeneration is a complex process influenced by various physiological factors. Platelet-rich plasma (PRP) contains many growth factors and has shown osteogenic effects. The PRP is usually activated before use. However, the authors showed that nonactivated PRP (nPRP) and activated PRP have comparable osteogenic effects in the previous study. Generally, a scaffold has been needed for the application of PRP in the cranial defect model. In this study, the authors aimed to compare the performance of scaffold free platelet-rich fibrin (PRF) to nPRP as an adjuvant for bone regeneration.Twenty-four New Zealand White rabbits were randomly allocated into 3 groups: control, nPRP, and PRF. A 15 × 15 mm defect was created on each rabbit's cranium. Acellular collagen sponges (Gelfoam) were placed on the defects of the control group, Gelfoam with nPRP was used for the nPRP group, and PRF membrane was directly applied for the PRF group. nPRP and PRF were obtained from each subject's peripheral blood. Sixteen weeks later, the volume of regenerated bone was measured using 3-dimensional computed tomography. The surface area was measured via autopsy, and the samples were then obtained for histological analysis.Bone regeneration in the experimental groups was significantly greater than that in the control group. There were no significant differences in the area of regeneration or histological characteristics between the nPRP and PRF groups.In the calvarial defect of the rabbits, the use of PRF and scaffolded PRP showed comparable bone regeneration effects, which suggested that PRF might be a therapeutic alternative for bone grafts.

Versatile Tandem Ring-Opening/Ring-Closing Metathesis Polymerization: Strategies for Successful Polymerization of Challenging Monomers and Their Mechanistic Studies.

Tandem ring-opening/ring-closing metathesis (RO/RCM) results in extremely fast living polymerization; however, according to previous reports, only monomers containing certain combinations of cycloalkenes, terminal alkynes, and nitrogen linkers successfully underwent tandem polymerization. After examining the polymerization pathways, we proposed that the relatively slow intramolecular cyclization might lead to competing side reactions such as intermolecular cross metathesis reactions to form inactive propagating species. Thus, we developed two strategies to enhance tandem polymerization efficiency. First, we modified monomer structures to accelerate tandem RO/RCM cyclization by enhancing the Thorpe-Ingold effect. This strategy increased the polymerization rate and suppressed the chain transfer reaction to achieve controlled polymerization, even for challenging syntheses of dendronized polymers. Alternatively, reducing the reaction concentration facilitated tandem polymerization, suggesting that the slow tandem RO/RCM cyclization step was the main reason for the previous failure. To broaden the monomer scope, we used monomers containing internal alkynes and observed that two different polymer units with different ring sizes were produced as a result of nonselective α-addition and ß-addition on the internal alkynes. Thorough experiments with various monomers with internal alkynes suggested that steric and electronic effects of the alkyne substituents influenced alkyne addition selectivity and the polymerization reactivity. Further polymerization kinetics studies revealed that the rate-determining step of monomers containing certain internal alkynes was the six-membered cyclization step via ß-addition, whereas that for other monomers was the conventional intermolecular propagation step, as observed in other chain-growth polymerizations. This conclusion agrees well with all those polymerization results and thus validates our strategies.

Highly ß-Selective Cyclopolymerization of 1,6-Heptadiynes and Ring-Closing Enyne Metathesis Reaction Using Grubbs Z-Selective Catalyst: Unprecedented Regioselectivity for Ru-Based Catalysts.

It is well-known that Ru-based Grubbs catalysts undergo a highly selective α-addition to alkynes to promote exo-cyclization during ring-closing enyne metathesis (RCEYM) or to produce conjugated polyenes containing five-membered rings during the cyclopolymerization (CP) of 1,6-heptadiynes. There are a few reports of ß-selective addition to alkynes using Schrock catalysts based on Mo but none for readily accessible and easy-to-use Ru-based catalysts. We report the first example of ß-selective addition to alkynes using Grubbs Z-selective catalyst, which produces only endo products during the RCEYM reaction of terminal enynes and promotes the CP of 1,6-heptadiyne derivatives to give conjugated polyenes containing a six-membered ring as a major repeat unit. This unique preference for ß-selectivity originated from the side-bound approach of alkynes to the catalyst, where the steric hindrance between the chelating N-heterocyclic carbene ligand of the catalyst and the alkynes disfavored α-addition. To enhance the ß-selectivity for CP further, one could increase the size of the substrates on the monomers and lower the reaction temperature to obtain conjugated polyenes containing up to 95% six-membered rings. Moreover, the physical properties of the resulting polymer were analyzed in detail and compared with those of the conjugated polyenes containing only five-membered rings prepared from the same monomer but with a conventional Grubbs catalyst.

Acceleration of osteogenesis by platelet-rich plasma with acellular dermal matrix in a calvarial defect model.

PURPOSE: The effects of platelet-rich plasma (PRP) on improvement of bone regeneration have been widely investigated. However, use of a proper scaffold is also important to the delivery of bioactive materials. The aim of this study was to analyze the effects of PRP with acellular dermal matrix (ADM) as a bone substitute in a cranial defect model. METHODS: Twenty-nine New Zealand white rabbits were randomly divided into four groups including control, PRP, ADM, and PRP with ADM. A 15 × 15-mm(2) bony defect was carefully created in the cranium. The experimental materials were applied in each group. After 16 weeks, the volume and surface area of new bone were measured using three-dimensional computed tomography and digital photography, and the new bone was analyzed histologically. RESULTS: The PRP with ADM group exhibited a statistically significant increase in volume and surface area of newly formed bone compared with the other groups (p < 0.05). Histological findings revealed compact lamellar bone in the PRP with ADM group. In contrast, scattered bone islands were detected within the fibrous connective tissue in the other groups. CONCLUSIONS: The regeneration of mature and augmented bone was achieved following the application of PRP mixed with ADM. The results indicated that the PRP combined with ADM could be a potentially useful substitute for bone and may aid in the elimination of additional donor-site harvest procedures.

Comparing the Effect of Nonactivated Platelet-Rich Plasma, Activated Platelet-Rich Plasma, and Bone Morphogenetic Protein-2 on Calvarial Bone Regeneration.

Although platelet-rich plasma (PRP) is widely used to enhance bone graft survival, the effect of PRP itself on bone regeneration is unclear. Because activated PRP releases many growth factors in a bolus, there are controversies regarding the effect of activation of the PRP on bone regeneration. Thus, we studied the effect of activated versus nonactivated PRP on bone regeneration and compared the effect with that of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a critical-sized cranial defect model. Forty New Zealand white rabbits were randomly divided into 4 groups. Defect sizing 15 × 15 mm(2) was created on the cranium of each rabbit, and then a collagen sponge soaked with normal saline, rhBMP-2, nonactivated PRP, or PRP activated with CaCl2 solution was immediately placed on the defect. After 16 weeks, using three-dimensional computed tomography and digital photography, the volume and new bone surface area were measured. The newly created bone was histologically analyzed. The experimental groups showed a significantly increased volume and surface area of new bone compared with the control group (P < 0.05), but no significant differences were found among the experimental groups. Histologic examination in the experimental groups showed newly created bone that had emerged in the center as well as the margin of the defect. Overall, these results indicate that PRP enhanced bony regeneration regardless of activation with an effect that was comparable to that of rhBMP-2. Thus, PRP has therapeutic effects on bone regeneration and may replace rhBMP-2, which is costly.

Strategies to enhance cyclopolymerization using third-generation Grubbs catalyst.

Cyclopolymerization (CP) of 1,6-heptadiyne derivatives using the Grubbs catalysts has been known to afford conjugated polyenes in low yields in dichloromethane (DCM), the most common solvent for olefin metathesis polymerization and a good solvent for typical conjugated polymers. Based on our previous work that showed highly efficient CP using the Grubbs catalysts in tetrahydrofuran (THF), we developed a new polymerization system using weakly coordinating additives with the third-generation Grubbs catalyst in DCM. The polymerization efficiency of various monomers and their controls dramatically increased by adding 3,5-dichloropyridine, yielding polymers with narrow polydispersity indices (PDIs) at low temperatures. These new reaction conditions not only expand the monomer scope by resolving the solubility concerns of conjugated polymers but also more effectively reduced the chain transfer. Consequently, fully conjugated diblock copolymer was successfully prepared. Additionally, kinetic analysis has revealed that low CP efficiency in DCM resulted from the rapid decomposition of the propagating carbene. This decomposition was effectively suppressed by both pyridine additives and THF, suggesting that weakly coordinating additives stabilize the living chain end. Furthermore, we observed that the turnover number of CP was higher at lower temperatures (0-10 °C) than at ambient temperatures, consistent with the understanding that the lifetime of a propagating carbene is greater at lower temperatures. Steric protection was also shown to increase the stability of the propagating carbene, as shown by a higher turnover number for the 3,3-dimethyl-substituted 1,6-heptadiyne compared to the nonfunctionalized monomer.

Drug Response of Patient-Derived Lung Cancer Cells Predicts Clinical Outcomes of Targeted Therapy.

Intratumor heterogeneity leads to different responses to targeted therapies, even within patients whose tumors harbor identical driver oncogenes. This study examined clinical outcomes according to a patient-derived cell (PDC)-based drug sensitivity test in lung cancer patients treated with targeted therapies. From 487 lung cancers, 397 PDCs were established with a success rate of 82%. In 139 PDCs from advanced non-small-cell lung cancer (NSCLC) patients receiving targeted therapies, the standardized area under the curve (AUC) values for the drugs was significantly correlated with their tumor response (p = 0.002). Among 59 chemo-naive EGFR/ALK-positive NSCLC patients, the PDC non-responders showed a significantly inferior response rate (RR) and progression-free survival (PFS) for the targeted drugs than the PDC responders (RR, 25% vs. 78%, p = 0.011; median PFS, 3.4 months [95% confidence interval (CI), 2.8-4.1] vs. 11.8 months [95% CI, 6.5-17.0], p < 0.001). Of 25 EGFR-positive NSCLC patients re-challenged with EGFR inhibitors, the PDC responder showed a higher RR than the PDC non-responder (42% vs. 15%). Four patients with wild-type EGFR or uncommon EGFR-mutant NSCLC were treated with EGFR inhibitors based on their favorable PDC response to EGFR inhibitors, and two patients showed dramatic responses. Therefore, the PDC-based drug sensitivity test results were significantly associated with clinical outcomes in patients with EGFR- or ALK-positive NSCLC. It may be helpful for predicting individual heterogenous clinical outcomes beyond genomic alterations.

Establishment of a human embryonic stem cell line, WAe009-A-99, with constitutive expression of the dCas9-p300 fusion protein.

CRISPR/Cas9-based transcriptional regulation systems can induce the site-specific activation or repression of endogenous genes. p300 is a transcriptional co-activator that functions as a histone acetyltransferase that regulates gene transcription via chromatin remodeling. Here, we generated a human embryonic stem cell line stably expressing catalytically dead Cas9 (dCas9) fused to the catalytic core domain of human p300 via lentiviral transduction. This cell line can be used for locus-specific histone acetylation in combination with guide RNAs, and is a valuable tool for gene regulation in stem cell research.

Study on the Migration Behaviors of Magnesium Oxysulfate Nano-Whiskers in Polypropylene Composites with Surface Modification.

In this study, surface modification aimed to enhance the compatibility between a hydrophilic inorganic filler and polypropylene (PP) matrix using hydrophobic treatment. Lauric acid, butyl acrylate, and maleic anhydride were employed to modify the filler surface. After treatment, inorganic filler/PP composites were produced using melt-mixing and extrusion-injection molding processes. The study focused on investigating compatibility and migration behavior between the filler and matrix. The findings indicated that hydrophobic modification, specifically with butyl acrylate and maleic anhydride, improved migration issues in nano-whisker, while maintaining favorable mechanical properties even under accelerated thermal aging. However, excessive hydrophobicity induced by superhydrophobic treatment using lauric acid led to reduced compatibility with the matrix, compromising its effectiveness. Consequently, the study revealed the potential of surface modification to enhance interfacial properties and mitigate migration concerns in PP composites for automotive applications.

Molecular Subtypes and Tumor Microenvironment Characteristics of Small-Cell Lung Cancer Associated with Platinum-Resistance.

Although molecular subtypes of small-cell lung cancer (SCLC) have been proposed, their clinical relevance and therapeutic implications are not fully understood. Thus, we aimed to refine molecular subtypes and to uncover therapeutic targets. We classified the subtypes based on gene expression (n = 81) and validated them in our samples (n = 87). Non-SCLC samples were compared with SCLC subtypes to identify the early development stage of SCLC. Single-cell transcriptome analysis was applied to dissect the TME of bulk samples. Finally, to overcome platinum resistance, we performed drug screening of patient-derived cells and cell lines. Four subtypes were identified: the ASCL1+ (SCLC-A) subtype identified as TP53/RB-mutated non-SCLC representing the early development stage of SCLC; the immune activation (SCLC-I) subtype, showing high CD8+/PD-L1+ T-cell infiltration and endothelial-to-mesenchymal transition (EndMT); the NEUROD1 (SCLC-N) subtype, which showed neurotransmission process; and the POU2F3+ (SCLC-P) subtype with epithelial-to-mesenchymal transition (EMT). EndMT was associated with the worst prognosis. While SCLC-A/N exhibited platinum sensitivity, the EndMT signal of SCLC-I conferred platinum resistance. A BET inhibitor suppressed the aggressive angiogenesis phenotype of SCLC-I. We revealed that EndMT development contributed to a poor outcome in SCLC-I. Moreover, heterogenous TME development facilitated platinum resistance. BET inhibitors are novel candidates for overcoming platinum resistance.

Patient-derived cell-based pharmacogenomic assessment to unveil underlying resistance mechanisms and novel therapeutics for advanced lung cancer.

BACKGROUND: A pharmacogenomic platform using patient-derived cells (PDCs) was established to identify the underlying resistance mechanisms and tailored treatment for patients with advanced or refractory lung cancer. METHODS: Drug sensitivity screening and multi-omics datasets were acquired from lung cancer PDCs (n = 102). Integrative analysis was performed to explore drug candidates according to genetic variants, gene expression, and clinical profiles. RESULTS: PDCs had genomic characteristics resembled with those of solid lung cancer tissues. PDC molecular subtyping classified patients into four groups: (1) inflammatory, (2) epithelial-to-mesenchymal transition (EMT)-like, (3) stemness, and (4) epithelial growth factor receptor (EGFR)-dominant. EGFR mutations of the EMT-like subtype were associated with a reduced response to EGFR-tyrosine kinase inhibitor therapy. Moreover, although RB1/TP53 mutations were significantly enriched in small-cell lung cancer (SCLC) PDCs, they were also present in non-SCLC PDCs. In contrast to its effect in the cell lines, alpelisib (a PI3K-AKT inhibitor) significantly inhibited both RB1/TP53 expression and SCLC cell growth in our PDC model. Furthermore, cell cycle inhibitors could effectively target SCLC cells. Finally, the upregulation of transforming growth factor-ß expression and the YAP/TAZ pathway was observed in osimertinib-resistant PDCs, predisposing them to the EMT-like subtype. Our platform selected XAV939 (a WNT-TNKS-ß-catenin inhibitor) for the treatment of osimertinib-resistant PDCs. Using an in vitro model, we further demonstrated that acquisition of osimertinib resistance enhances invasive characteristics and EMT, upregulates the YAP/TAZ-AXL axis, and increases the sensitivity of cancer cells to XAV939. CONCLUSIONS: Our PDC models recapitulated the molecular characteristics of lung cancer, and pharmacogenomics analysis provided plausible therapeutic candidates.

MYC amplification-conferred primary resistance to capmatinib in a MET-amplified NSCLC patient: a case report.

Background: Capmatinib, a potent and selective mesenchymalepithelial transition factor (MET) inhibitor, is an effective treatment option for non-small cell lung cancer (NSCLC) patients with MET exon 14 skipping mutations or gene amplification. However, the mechanisms that confer resistance to capmatinib remain elusive. Here, we present a case of primary resistance to capmatinib in a MET-amplified NSCLC patient which was conferred by concurrent MYC amplification. Case Description: Capmatinib was administered as first-line treatment in an 82-year-old MET-amplified [gene copy number (GCN) 13.5] and MET overexpressed (immunohistochemical staining 3+/3, >50%) NSCLC patient. However, the tumor rapidly progressed and showed primary resistance to capmatinib. Next-generation target sequencing using rebiopsy tumor samples revealed MYC amplification. We also performed functional drug susceptibility testing using patient-derived cells (PDCs), which showed overexpression of MYC mRNA and resistance to capmatinib. Meanwhile, ICX-101, an investigational MYC inhibitor, successfully inhibited the growth of PDCs at a relatively low IC50 value. Also, a synergistic effect was shown when capmatinib treatment was followed by ICX-101. Conclusions: Concurrent MYC amplification could potentially confer primary resistance to capmatinib in highly MET amplified NSCLC patients. Further clinical studies are warranted to corroborate these findings, and treatment with MYC inhibitors could be suggested as an alternative therapeutic strategy for this subset of patients.

Development of human pluripotent stem cell-derived hepatic organoids as an alternative model for drug safety assessment.

Human in vitro hepatic models that faithfully recapitulate liver function are essential for successful basic and translational research. A limitation of current in vitro models, which are extensively used for drug discovery and toxicity testing, is the loss of drug metabolic function due to the low expression and activity of cytochrome P450 (CYP450) enzymes. Here, we aimed to generate human pluripotent stem cell-derived hepatic organoids (hHOs) with a high drug metabolic ability. We established a two-step protocol to produce hHOs from human pluripotent stem cells for long-term expansion and drug testing. Fully differentiated hHOs had multicellular composition and exhibited cellular polarity and hepatobiliary structures. They also displayed remarkable CYP450 activity and recapitulated the metabolic clearance, CYP450-mediated drug toxicity, and metabolism. Furthermore, hHOs successfully modeled Wilson's disease in terms of Cu metabolism, drug responses, and diagnostic marker expression and secretion. In conclusion, hHOs exhibit high capacity for drug testing and disease modeling. Hence, this hepatic model system provides an advanced tool for studying hepatic drug metabolism and diseases.

Ultrafast cyclopolymerization for polyene synthesis: living polymerization to dendronized polymers.

We discovered that ultrafast cyclopolymerization of 1,6-heptadiyne derivatives reached completion in 1 min using a third-generation Grubbs catalyst. After optimization, this superior catalyst selectively produced conjugated polymers having a five-membered-ring structure with excellent molecular weight control and narrow polydispersity index (PDI). This living polymerization allowed us to prepare fully conjugated diblock copolymers with narrow PDIs. Lastly, this catalyst was active enough to polymerize macromonomers with G-3 dendrons in a living manner as well. This dendronized polymer with a highly regioregular polymer backbone and bulky dendrons was visualized by atomic force microscopy, which revealed the structure of a single molecular wire surrounded by insulating dendrons.