Clinical molecular subtyping reveals intrinsic mesenchymal reprogramming in gastric cancer cells.

The mesenchymal cancer phenotype is known to be clinically related to treatment resistance and a poor prognosis. We identified gene signature-based molecular subtypes of gastric cancer (GC, n = 547) based on transcriptome data and validated their prognostic and predictive utility in multiple external cohorts. We subsequently examined their associations with tumor microenvironment (TME) features by employing cellular deconvolution methods and sequencing isolated GC populations. We further performed spatial transcriptomics analysis and immunohistochemistry, demonstrating the presence of GC cells in a partial epithelial-mesenchymal transition state. We performed network and pharmacogenomic database analyses to identify TGF-ß signaling as a driver pathway and, thus, a therapeutic target. We further validated its expression in tumor cells in preclinical models and a single-cell dataset. Finally, we demonstrated that inhibition of TGF-ß signaling negated mesenchymal/stem-like behavior and therapy resistance in GC cell lines and mouse xenograft models. In summary, we show that the mesenchymal GC phenotype could be driven by epithelial cancer cell-intrinsic TGF-ß signaling and propose therapeutic strategies based on targeting the tumor-intrinsic mesenchymal reprogramming of medically intractable GC.

MRI measurement of alanine uptake in a mouse xenograft model of U-87 MG glioblastoma.

The potential use of alanine as an MRI contrast agent was investigated. The relaxation properties of alanine solutions were measured at 9.4 T. The T2 relaxivity caused by the chemical exchange (R2ex) between amine protons and water protons was 0.10 mM-1 s-1 at 37 °C. As a demonstration, alanine uptake in a mouse xenograft model of U-87 MG glioblastoma was measured using MRI, and was compared with immunohistochemistry staining of ASCT2, a transporter that imports amino acids into cancer cells. Statistically significant (p = 0.0079) differences in ASCT2 distribution were found between regions that show strong and weak alanine uptake in MRI. To better understand the influence of perfusion, the effect of ASCT2 inhibition on the alanine uptake in MRI was investigated, and dynamic contrast enhanced MRI was compared with alanine MRI.

Correction to: No prominent toxicity of polyethylene microplastics observed in neonatal mice following intratracheal instillation to dams during gestational and neonatal period.

[This corrects the article DOI: 10.1007/s43188-020-00086-7.].

No prominent toxicity of polyethylene microplastics observed in neonatal mice following intratracheal instillation to dams during gestational and neonatal period.

Microplastics (MPs) have been recently recognized as a global environmental threat and its exposure as a risk factor to human health. Health effects through MPs exposure have been recently reported, especially through oral route of exposure. Since MPs could be exposed to humans through routes other than oral, this study was designed to evaluate whether MPs exposed through the inhalation route could be delivered to fetal mice and exhibit systemic toxicity. Polyethylene (PE) with 10-45 µm diameter were administered at 0 (distilled water, vehicle control), 6 (low administration), and 60 (high administration) µg/mouse/day to 3 pregnant dams per group from gestational day 9 to postnatal day (PND) 7 through intratracheal instillation. Dams and neonates were sacrificed at PND 7 and blood was collected. Various neonatal organs including brain, lung, heart, stomach, intestine, kidneys, and ovaries were collected for histopathological observation and weight measurement. No influence of PE-MPs administration was observed on the number of offsprings born, but the body and organs' weight were heavier overall in the high administration group of dams and neonates than the other groups with statistical significance achieved in the heart and spleen weight. Level of serum acetylcholinesterase and glutathione peroxidase activity was decreased in the high administration group of dams and neonates compared with the other groups. Lung was the organ with highest number of PE-MPs present in the both administration groups of dams, and PE-MPs were also detected in liver and intestine of the high administration dams. Whereas, PND7 neonates showed accountable numbers of PE-MPs only in kidneys of the high administration group. Overall, the present study indicates that PE-MPs instilled intratracheally could be delivered to neonates from dams. Even though adverse effects from PE-MPs exposure during pregnant and lactational period are less prominent on both dam and neonate, potential of second-generation toxicity could be considered for further investigation.

Influence of alignment and microstructure features on the mechanical properties and failure mechanisms of cellulose nanocrystals (CNC) films.

The mechanical properties of cellulose nanocrystal (CNC) films critically depend on many microstructural parameters such as fiber length distribution (FLD), fiber orientation distribution (FOD), and the strength of the interactions between the fibers. In this paper, we use our coarse-grained molecular model of CNC to study the effect of length and orientation distribution and attractions between CNCs on the mechanical properties of neat CNCs. The effect of misalignment of a 2D staggered structure of CNC with respect to the loading direction was studied with simulations and analytical solutions and then verified with experiments. To understand the effect of FLD and FOD on the mechanical performance, various 3D microstructures representing different case studies such as highly aligned, randomly distributed, short length CNCs and long length CNCs were generated and simulated. According to the misalignment study, three different failure modes: sliding mode, mixed mode, and normal mode were defined. Also, comparing the effects of FOD, FLD, and CNC interaction strength, shows that the adhesion strength is the only parameter that can significantly improve the mechanical properties, regardless of loading direction or FOD of CNCs.

L-glutamine as a T2 exchange contrast agent.

PURPOSE: The potential of L-glutamine as a T2 exchange contrast agent in MRI was investigated. METHODS: The T2 relaxation rate of L-glutamine solutions prepared in various concentrations was measured at 9.4 T. A series of T2 -weighted images in a mouse cancer model was acquired with an L-glutamine solution infusion. RESULTS: The T2 relaxivity caused by the exchange (R2ex ) at 37°C was 0.069 s-1 mM-1 and 0.102 s-1 mM-1 for glutamine and glutamate solutions at pH = 7.2, respectively. The R2ex of glutamine at pH = 6.1-6.7 was in the 0.097-0.1 s-1 mM-1 range. No significant dependence of T1 on the concentration of glutamine was observed. The dynamic measurement of T2 -weighted images in vivo showed that the glutamine uptake was primarily observed at the localized part of the tumor CONCLUSION: L-glutamine can be used as a T2 exchange contrast agent and images of glutamine uptake in vivo can be acquired.

Polymer thin film adhesion utilizing the transition from surface wrinkling to delamination.

Understanding the adhesion of rigid thin films to compliant substrates is critical for the development and implementation of flexible electronic devices and wearable sensor technologies. Quantifying the strength of a film-substrate interface can be challenging due to the brittleness of glassy films which can greatly complicate sample preparation, handling, and testing. Here, a method for measuring the adhesion of glassy thin films to soft elastomeric substrates is explored that exploits an understanding of surface buckling instabilities, specifically the transition from wrinkling to delamination. The adhesion (given by the critical strain energy release rate (Gc)) for two model materials' interfaces is quantified by determining the critical delamination strain for thin glassy polymer films (polystyrene (PS) and poly(methyl methacrylate) (PMMA)) from an elastomeric substrate (poly(dimethyl siloxane) (PDMS)). By accounting for edge defects that greatly reduce the critical strain for delamination, reasonable adjusted Gc values of 21.0 ± 5.1 mJ m-2 and 32.2 ± 4.9 mJ m-2 are found for PS-PDMS and PMMA-PDMS interfaces, respectively. The utilization of this method to characterize film modulus and adhesion could be used as a facile measurement technique for more applied polymer thin film systems.

PEGylated Magnetic Nano-Assemblies as Contrast Agents for Effective T2-Weighted MR Imaging.

We designed a high-sensitivity magnetic resonance imaging contrast agent that could be used to diagnose diseases. First, magnetic nanocrystals were synthesized by a thermal decomposition method on an organic solvent to obtain a high magnetism and methoxy poly(ethylene glycol)-poly(lactic acid) as an amphiphilic polymer using the ring-opening polymerization method to stably disperse the magnetic nanocrystals in an aqueous phase. Subsequently, the magnetic nanoclusters simultaneously self-assembled with methoxy poly(ethylene glycol)-poly(lactic acid) using the nano-emulsion method to form magnetic nanoclusters. Because their shape was similar to a raspberry, they were named PEGylated magnetic nano-assemblies. The PEGylated magnetic nano-assemblies were dispersed stably in the aqueous phase with a uniform size of approximately 65⁻70 nm for an extended period (0 days: 68.8 ± 5.1 nm, 33 days: 69.2 ± 2.0 nm, and 44 days: 63.2 ± 5.6). They exhibited both enough of a magnetic resonance (MR) contrast effect and biocompatibility. In an in vivo study, the PEGylated magnetic nano-assemblies provided a high contrast effect for magnetic resonance images for a long time after one treatment, thereby improving the diagnostic visibility of the disease site.

Fluorescence amplified sensing platforms enabling miRNA detection by self-circulation of a molecular beacon circuit.

We have proposed a novel strategy for miRNA detection through enzyme-free signal amplification by self-circulation of the hybridization between the miRNAs and molecular beacon (MB) circuits. Unlike general MB-based miRNA detection based on the one-to-one (1 : 1) hybridization between MBs and miRNA, our system consists of four species of MBs (MBs A, B, C and D) (MB circuits) and is activated by a hybridization chain reaction. MBs stably coexist as hairpin structures that hardly show fluorescence signals in the absence of target miRNA. After miRNA detection, this MB circuit is able to generate fluorescence signals and amplify the fluorescence signal, contributing to improvement in detection sensitivity under iso-thermal conditions without an enzyme. Furthermore, in vitro and in vivo studies have proven that MB circuits can detect low levels of miRNA with high sensitivity, compared to when only one MB alone is used. Therefore, the MB circuits can provide a useful platform for target miRNA detection.

FGF2 Signaling Plays an Important Role in Maintaining Pluripotent State of Pig Embryonic Germ Cells.

Germ cells are alternative sources for deriving pluripotent stem cells. Because embryonic germ cells (EGCs) possess physiological and developmental features similar to those of embryonic stem cells, pig EGCs are considered a potential tool for generating transgenic animals for agricultural usage. Therefore, in this study, we attempted to establish and characterize pig EGCs from fetal gonads. EGC lines were derived from the genital ridges of porcine fetuses in media containing leukemia inhibitory factor (LIF), fibroblast growth factor 2 (FGF2), and stem cell factor. After establishment, these cells were cultured and stabilized in LIF- or FGF2-containing media. The cell lines were maintained under both conditions over an extended time period and spontaneously differentiated into the three germ layers in vitro. Interestingly, expression of pluripotency markers showed different patterns between cell lines cultured in LIF or FGF2. SSEA4 was only expressed in FGF2-treated pig EGCs (FGF2-pEGCs), not LIF-treated pig EGCs (LIF-pEGCs). Pluripotency genes were upregulated in FGF2-pEGCs, and germline markers were highly expressed, indicating that FGF2 supplements are more efficient in supporting the pluripotency of pEGCs. In conclusion, we verified that FGF2 signaling plays an important role in reprogramming and maintaining pEGCs from fetal gonads.

Measuring water contents in animal organ tissues using terahertz spectroscopic imaging.

We investigated the water contents in several organ tissues such as the liver, spleen, kidney, and brain tissue of rats using the terahertz spectroscopic imaging technique. The water contents of the tissues were determined by using a simple equation containing the absorption coefficients of fresh and lyophilized tissues and water. We compared the measured water contents with the difference in mass of tissues before and after lyophilization. All results showed a good match except for the kidney, which has several Bowman's capsules.

Convenient Monitoring System of Intracellular microRNA Expression during Adipogenesis via Mechanical Stimulus-Induced Exocytosis of Lipovesicular miRNA Beacon.

Noninvasive investigation of microRNAs (miRNAs) expression, which is deeply related to biological phenomena such as stem cell differentiation, in culture soup is particularly useful for monitoring of stem cell differentiation without phototoxicity of living cells, especially when cell morphologies remain unchanged during differentiation. However, real-time detection of miRNA in culture soup is not recommended because of insufficient miRNA amounts in culture soup. In this study, a convenient method is introduced for real-time assessing intracellular miRNA in culture soup by using lipovesicular miRNA beacon (Lipo-mB) and mechanical stimulus-mediated exocytosis. Pipetting-harvest of culture soup induces exocytosis-secretion of fluorescence signal of Lipo-mB from cytoplasm into culture soup. To demonstrate this method, Lipo-mB is applied for monitoring of adipogenesis by analyzing the expression levels of various intracellular miRNAs, which are related to adipogenesis regulators. The fluorescence intensity profile of the culture soup is correlated with the quantitative reverse-transcription-polymerase chain reaction data and absorbance of Oil Red O staining. These results demonstrate that Lipo-mB can successfully monitor stem cell differentiation by sensing changes in miRNA expression from culture soup of living cells. Lipo-mB can be further developed as an accurate sensing system for analyzing subtle differences in genotype, even when changes in phenotype cannot be observed.

Nanovesicle-mediated systemic delivery of microRNA-34a for CD44 overexpressing gastric cancer stem cell therapy.

The cancer stem cell (CSC) hypothesis postulates that cancer cells overexpressing CD44 are marked as CSCs that cause tumorigenesis and recurrence. This hypothesis suggests that CD44 is a potential therapeutic target that can interfere with CSCs qualities. MicroRNA-34a (miR-34a) is a promising candidate for CD44 repression-based cancer therapy as it has been reported to inhibit proliferation, metastasis, and survival of CD44-positive CSCs. Here, we used nanovesicles containing PLI/miR complexes (NVs/miR) to systemically deliver miR-34a and induce miR-34a-triggered CD44 suppression in orthotopically and subcutaneously implanted tumors in nude mice. Poly(l-lysine-graft-imidazole) (PLI) condenses miRs and is functionally modified to deliver miRs to the site of action by buffering effect of imidazole residues under endosomal pH. Indeed, NVs/miR consisting of PEGylated lipids enveloping PLI/miR complexes greatly reduced inevitable toxicity of polycations by compensating their surface charge and markedly improved their in vivo stability and accumulation to tumor tissue compared to PLI/miR polyplexes. Our NVs-mediated miR-34a delivery system specifically increased endogenous target miR levels, thereby attenuating proliferation and migration of gastric cancer cells by repressing the expression of CD44 with decreased levels of Bcl-2, Oct 3/4 and Nanog genes. Our strategy led to a greater therapeutic outcome than PLI-based delivery with highly selective tumor cell death and significantly delayed tumor growth in CD44-positive tumor-bearing mouse models, thus providing a fundamental therapeutic window for CSCs.

Redoxable heteronanocrystals functioning magnetic relaxation switch for activatable T1 and T2 dual-mode magnetic resonance imaging.

T1/T2 dual-mode magnetic resonance (MR) contrast agents (DMCAs) have gained much attention because of their ability to improve accuracy by providing two pieces of complementary information with one instrument. However, most of these agents are "always ON" systems that emit MR contrast regardless of their interaction with target cells or biomarkers, which may result in poor target-to-background ratios. Herein, we introduce a rationally designed magnetic relaxation switch (MGRS) for an activatable T1/T2 dual MR imaging system. Redox-responsive heteronanocrystals, consisting of a superparamagnetic Fe3O4 core and a paramagnetic Mn3O4 shell, are synthesized through seed-mediated growth and subsequently surface-modified with polysorbate 80. The Mn3O4 shell acts as both a protector of Fe3O4 in aqueous environments to attenuate T2 relaxation and as a redoxable switch that can be activated in intracellular reducing environments by glutathione. This simultaneously generates large amounts of magnetically decoupled Mn(2+) ions and allows Fe3O4 to interact with the water protons. This smart nanoplatform shows an appropriate hydrodynamic size for the EPR effect (10-100 nm) and demonstrates biocompatibility. Efficient transitions of OFF/ON dual contrast effects are observed by in vitro imaging and MR relaxivity measurements. The ability to use these materials as DMCAs is demonstrated via effective passive tumor targeting for T1- and T2-weighted MR imaging in tumor-bearing mice.

Embryo Aggregation Promotes Derivation Efficiency of Outgrowths from Porcine Blastocysts.

Porcine embryonic stem cells (pESCs) have become an advantageous experimental tool for developing therapeutic applications and producing transgenic animals. However, despite numerous reports of putative pESC lines, deriving validated pESC lines from embryos produced in vitro remains difficult. Here, we report that embryo aggregation was useful for deriving pESCs from in vitro-produced embryos. Blastocysts derived from embryo aggregation formed a larger number of colonies and maintained cell culture stability. Our derived cell lines demonstrated expression of pluripotent markers (alkaline phosphatase, Oct4, Sox2, and Nanog), an ability to form embryoid bodies, and the capacity to differentiate into the three germ layers. A cytogenetic analysis of these cells revealed that all lines derived from aggregated blastocysts had normal female and male karyotypes. These results demonstrate that embryo aggregation could be a useful technique to improve the efficiency of deriving ESCs from in vitro-fertilized pig embryos, studying early development, and deriving pluripotent ESCs in vitro in other mammals.

Sulfur deposition simulations over China, Japan, and Korea: a model intercomparison study for abating sulfur emission.

In response to increasing trends in sulfur deposition in Northeast Asia, three countries in the region (China, Japan, and Korea) agreed to devise abatement strategies. The concepts of critical loads and source-receptor (S-R) relationships provide guidance for formulating such strategies. Based on the Long-range Transboundary Air Pollutants in Northeast Asia (LTP) project, this study analyzes sulfur deposition data in order to optimize acidic loads over the three countries. The three groups involved in this study carried out a full year (2002) of sulfur deposition modeling over the geographic region spanning the three countries, using three air quality models: MM5-CMAQ, MM5-RAQM, and RAMS-CADM, employed by Chinese, Japanese, and Korean modeling groups, respectively. Each model employed its own meteorological numerical model and model parameters. Only the emission rates for SO(2) and NO(x) obtained from the LTP project were the common parameter used in the three models. Three models revealed some bias from dry to wet deposition, particularly the latter because of the bias in annual precipitation. This finding points to the need for further sensitivity tests of the wet removal rates in association with underlying cloud-precipitation physics and parameterizations. Despite this bias, the annual total (dry plus wet) sulfur deposition predicted by the models were surprisingly very similar. The ensemble average annual total deposition was 7,203.6 ± 370 kt S with a minimal mean fractional error (MFE) of 8.95 ± 5.24 % and a pattern correlation (PC) of 0.89-0.93 between the models. This exercise revealed that despite rather poor error scores in comparison with observations, these consistent total deposition values across the three models, based on LTP group's input data assumptions, suggest a plausible S-R relationship that can be applied to the next task of designing cost-effective emission abatement strategies.

Comparison of oral omeprazole and endoscopic ethanol injection therapy for prevention of recurrent bleeding from peptic ulcers with nonbleeding visible vessels or fresh adherent clots.

OBJECTIVES: Omeprazole is a potent inhibitor of gastric acid secretion. Recently it was reported that p.o. omeprazole therapy reduced the rebleeding rate in patients with nonbleeding visible vessels or adherent clots. The aim of this study was to ascertain whether p.o. administration of omeprazole can be an effective alternative to endoscopic injection therapy in peptic ulcers with stigmata of recent hemorrhage. METHODS: A total of 101 patients who had peptic ulcer bleeding based on endoscopic findings of nonbleeding visible vessels or fresh adherent clots were randomly assigned to receive omeprazole (40 mg p.o. every 12 h) or endoscopic ethanol injection therapy. RESULTS: Rebleeding rates were 22.9% (11 of 48) in the omeprazole group and 20.8% (11 of 53) in the endoscopic injection therapy group. The rebleeding rates of clinical significance were 14.6% and 13.2%, respectively. There was no significance difference in the rebleeding rate, requirement for surgery, total units of blood transfused, or mortality between the two groups. CONCLUSIONS: Oral omeprazole administration is comparable to endoscopic ethanol injection therapy for prevention of rebleeding in patients with nonbleeding visible vessels or adherent clots.