Chrysophanol induces apoptosis and ferroptosis of gastric cancer cells by targeted regulation of mTOR.

Programmed cell death (PCD) induction is a promising strategy for killing gastric cancer cells. In this study, we investigated the effects of chrysophanol on apoptosis and ferroptosis in gastric cancer cells. Chrysophanol in concentrations ranging from 0 to 100 µM were used to treat GES-1, HGC-27 and AGS cells. Cell counting kit-8 assay, colony formation assay, 5-ethynyl-2'-deoxyuridine staining, flow cytometry, JC-1 probe insertion, dihydroethidium staining and western blotting were performed. The effects of chrysophanol on gastric cancer cells were evaluated in vivo using a xenograft mouse model. Chrysophanol had no cytotoxic effects on GES-1 cells. Chrysophanol with concentrations higher than 25 µM inhibited gastric cancer cell colony formation and proliferation. Chrysophanol induces gastric cancer cell apoptosis in a dose-dependent manner, accompanied by mitochondrial membrane potential dysfunction and cytochrome c release. Additionally, chrysophanol increased the levels of reactive oxygen species, total iron, and Fe2+ in HGC-27 and AGS cells, in a dose-dependent manner. Treatment of cells with the ferroptosis inhibitor ferrostatin-1 attenuated the effects of chrysophanol on cell survival and the expression of ferroptosis markers SLC7A11 and GPX4. Screening by GEO software indicated that the mTOR signalling pathway is possibly regulated by chrysophanol. Furthermore, mTOR overexpression significantly reversed the inhibitory effects of chrysophanol on gastric cancer cells. In gastric cancer xenograft mouse models, chrysophanol treatment inhibited tumour growth and downregulated SLC7A11 and GPX4. Chrysophanol induces apoptosis and ferroptosis, making it a potential candidate for killing gastric cancer cells. The beneficial effects of chrysophanol may be attribute to the targeted regulation of mTOR.

Integral Reinforcement-Learning-Based Optimal Containment Control for Partially Unknown Nonlinear Multiagent Systems.

This paper focuses on the optimal containment control problem for the nonlinear multiagent systems with partially unknown dynamics via an integral reinforcement learning algorithm. By employing integral reinforcement learning, the requirement of the drift dynamics is relaxed. The integral reinforcement learning method is proved to be equivalent to the model-based policy iteration, which guarantees the convergence of the proposed control algorithm. For each follower, the Hamilton-Jacobi-Bellman equation is solved by a single critic neural network with a modified updating law which guarantees the weight error dynamic to be asymptotically stable. Through using input-output data, the approximate optimal containment control protocol of each follower is obtained by applying the critic neural network. The closed-loop containment error system is guaranteed to be stable under the proposed optimal containment control scheme. Simulation results demonstrate the effectiveness of the presented control scheme.

Event-triggered adaptive dynamic programming for decentralized tracking control of input constrained unknown nonlinear interconnected systems.

This paper addresses decentralized tracking control (DTC) problems for input constrained unknown nonlinear interconnected systems via event-triggered adaptive dynamic programming. To reconstruct the system dynamics, a neural-network-based local observer is established by using local input-output data and the desired trajectories of all other subsystems. By employing a nonquadratic value function, the DTC problem of the input constrained nonlinear interconnected system is transformed into an optimal control problem. By using the observer-critic architecture, the DTC policy is obtained by solving the local Hamilton-Jacobi-Bellman equation through the local critic neural network, whose weights are tuned by the experience replay technique to relax the persistence of excitation condition. Under the event-triggering mechanism, the DTC policy is updated at the event-triggering instants only. Then, the computational resource and the communication bandwidth are saved. The stability of the closed-loop system is guaranteed by implementing event-triggered DTC policy via Lyapunov's direct method. Finally, simulation examples are provided to demonstrate the effectiveness of the proposed scheme.

A novel matrine derivative, WM130, inhibits activation and movement of human hepatic stellate LX-2 cells by targeting cofilin 1.

Matrine, one of the active ingredients of Sophora flavescens Ait., has a protective effect in animal models on acute liver injury and liver fibrosis. However, since the protective effects are short-lived, a structural modification of matrine is needed to improve its anti-fibrotic effects. In the previous study we obtained a stable, highly active new matrine derivative, WM130, and explored its anti-fibrotic effects on the human hepatic stellate cell line, LX-2. CCK-8, wound healing, and transwell assays were used to investigate cell proliferation and migration, while 3D mimic study was used to determine the target of WM130. Western blots investigated the levels of α-SMA, cofilin 1, p-cofilin 1, F-actin, PI3K, p-Akt, Akt, and PTEN in LX-2 cells treated with MW130. The results revealed that WM130 can significantly inhibit the proliferation of LX-2 cells at an IC50 of 60 µg/ml. At 30 µg/ml, matrine or WM130 significantly inhibited the migration of LX-2 cells. Moreover, WM130 significantly reduced the expression of α-SMA, cofilin 1, F-actin, PI3K, and p-Akt, and increased PTEN levels. In conclusion, WM130 inhibits the proliferation, activation, and migration of human hepatic stellate LX-2 cells by targeting cofilin 1. Supplementary Information: The online version contains supplementary material available at 10.1007/s10616-022-00548-w.

Synthesis and preliminary immunologic properties of di-/trisaccharide-conjugates related to Bacillus anthracis.

Herein, the di- and trisaccharide mimics of the hexasaccharide antigen related to Bacillus anthracis were synthesized and covalently coupled with carrier proteins, such as keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA), to form the corresponding glycoconjugates 1-6. 2,3,4,6-Tetra-O-benzyl thioglycoside and 2-deoxyl-2-phthalylamino-3,4,6-tri-O-benzyl thioglycoside were applied as glycosyl donors to guarantee α or ß-configuration of the newly formed glycosidic bonds. Glutaraldehyde was used as a homobifunctional cross-linker for high-efficiency coupling. The synthetic KLH-glycoconjugates 2, 4 and 6 were also used to vaccinate female Balb/c mice and the preliminary results of ELISA uncovered that all three KLH-conjugates could induce immune responses and generate oligosaccharide-specific total IgG antibodies. The trisaccharide 8, the glycosyl part of glycoconjugate 4, is of great immunogenicity.

Synthesis and immunological studies of ß-1,2-mannan-peptide conjugates as antifungal vaccines.

Fungal cell surface carbohydrates and proteins are useful antigens for the development of antifungal vaccines. In this study, glycopeptides consisting of the ß-1,2-mannan and N-terminal peptide epitopes of Candida albicans (C. albicans) cell wall phosphomannan complex and Als1p (rAls1p-N) protein, respectively, were synthesized and covalently conjugated with keyhole limpet hemocyanin (KLH) and human serum albumin (HSA) through homobifunctional disuccinimidyl glutarate. The resultant KLH-conjugates were immunologically evaluated using Balb/c mice to reveal that they induced high levels of IgG antibodies. Furthermore, these conjugates showed self-adjuvanting property, as they could promote robust antibody responses without the presence of an external adjuvant. More significantly, the obtained antisera could effectively recognize both the carbohydrate and the Als1 peptide epitopes and immunofluorescence and flow cytometry assays also demonstrated that the elicited antibodies could react with the cell surface of a number of fungi, including C. albicans, C. tropicalis, C. lustaniae and C. glabrata. These results suggested the great potential of these conjugates as antifungal vaccines.

WM130 preferentially inhibits hepatic cancer stem-like cells by suppressing AKT/GSK3ß/ß-catenin signaling pathway.

The eradication of cancer stem cells (CSCs) is significant for cancer therapy and prevention. In this study, we evaluated WM130, a novel derivative of matrine, for its effect on CSCs using human hepatocellular carcinoma (HCC) cell lines, their sphere cells, and sorted EpCAM+ cells. We revealed that WM130 could not only inhibit proliferation and colony formation of HCC cells, but also suppress the expression of some stemness-related genes and up-regulate some mature hepatocyte marker genes, indicating a promotion of differentiation from CSCs to hepatocytes. WM130 also suppressed the proliferation of doxorubicin-resistant hepatoma cells, and markedly reduced the cells with CSC biomarker EpCAM. Moreover, WM130 suppressed HCC spheres, not only primary spheres but also subsequent spheres, indicating an inhibitory effect on self-renewal capability of CSCs. Interestingly, WM130 exhibited a remarkable inhibitory preference on HCC spheres and EpCAM+ cells rather than their parental HCC cells and EpCAM- cells respectively. In vivo, WM130 inhibited HCC xenograft growth, decreased the number of sphere-forming cells, and remarkably decreased the levels of EpCAM mRNA and protein in tumor xenografts. Better inhibitory effect was achieved by WM130 in combination with doxorubicin. Further mechanism study revealed that WM130 inhibited AKT/GSK3ß/ß-catenin signaling pathway. Collectively, our results suggest that WM130 remarkably inhibits hepatic CSCs, and this effect may via the down-regulation of the AKT/GSK3ß/ß-catenin pathway. These findings provide a strong rationale for the use of WM130 as a novel drug candidate in HCC therapy.

6-O-Branched Oligo-ß-glucan-Based Antifungal Glycoconjugate Vaccines.

With the rapid growth in fungal infections and drug-resistant fungal strains, antifungal vaccines have become an especially attractive strategy to tackle this important health problem. ß-Glucans, a class of extracellular carbohydrate antigens abundantly and consistently expressed on fungal cell surfaces, are intriguing epitopes for antifungal vaccine development. ß-Glucans have a conserved ß-1,3-glucan backbone with sporadic ß-1,3- or ß-1,6-linked short glucans as branches at the 6-O-positions, and the branches may play a critical role in their immunologic functions. To study the immunologic properties of branched ß-glucans and develop ß-glucan-based antifungal vaccines, three branched ß-glucan oligosaccharides with 6-O-linked ß-1,6-tetraglucose, ß-1,3-diglucose, and ß-1,3-tetraglucose branches on a ß-1,3-nonaglucan backbone, which mimic the structural epitopes of natural ß-glucans, were synthesized and coupled with keyhole limpet hemocyanin (KLH) to form novel synthetic conjugate vaccines. These glycoconjugates were proved to elicit strong IgG antibody responses in mice. It was also discovered that the number, size, and structure of branches linked to the ß-glucan backbone had a significant impact on the immunologic property. Moreover, antibodies induced by the synthetic oligosaccharide-KLH conjugates were able to recognize and bind to natural ß-glucans and fungal cells. Most importantly, these conjugates elicited effective protection against systemic Candida albicans infection in mice. Thus, branched oligo-ß-glucans were identified as functional epitopes for antifungal vaccine design and the corresponding protein conjugates as promising antifungal vaccine candidates.

A six-membered-ring incorporated Si-rhodamine for imaging of copper(ii) in lysosomes.

The regulation of copper homeostasis in lysosomes of living cells is closely related to various physiological and pathological processes. Thus, it is of urgent need to develop a fluorescent probe for selectively and sensitively monitoring the location and concentration of lysosomal Cu(2+). Herein, a six-membered ring, thiosemicarbazide, was incorporated into a Si-rhodamine (SiR) scaffold for the first time, affording a SiR-based fluorescent probe SiRB-Cu. Through the effective Cu(2+)-triggered ring-opening process, the probe exhibits fast NIR chromogenic and fluorogenic responses to Cu(2+) within 2 min as the result of formation of a highly fluorescent product SiR-NCS. Compared with a five-membered ring, the expanded ring retains great tolerance to H(+), ensuring the superior sensitivity with a detection limit as low as 7.7 nM and 200-fold enhancement of relative fluorescence in the presence of 1.0 equiv. of Cu(2+) in pH = 5.0 solution, the physiological pH of lysosome. Moreover, the thiosemicarbazide moiety acts not only as the chelating and reactive site, but also as an efficient lysosome-targeting group, leading to the proactive accumulation of the probe into lysosomes. Taking advantage of these distinct properties, SiRB-Cu provides a functional probe suitable for imaging exogenous and endogenous lysosomal Cu(2+) with high imaging contrast and fidelity.

A Lysosome-Compatible Near-Infrared Fluorescent Probe for Targeted Monitoring of Nitric Oxide.

The requirement for nitric oxide (NO) of lysosomes has motivated the development of a sophisticated fluorescent probe to monitor the distribution of this important biomolecule at the subcellular level in living cells. A near-infrared (NIR) fluorescent Si-rhodamine (SiRB)-NO probe was designed based on the NO-induced ring-opening process of Si-rhodamine. The probe exhibits fast chromogenic and fluorogenic responses, and high sensitivity and selectivity toward trace amounts of NO. Significantly, the spirolactam in Si-rhodamine exhibits very good tolerance to H(+), which in turn brings extremely low background fluorescence not only in the physiological environment but also under acidic conditions. The stability of the highly fluorescent product in acidic solution provides persistent fluorescence emission for long-term imaging experiments. To achieve targeted imaging with improved spatial resolution and sensitivity, an efficient lysosome-targeting moiety was conjugated to a SiRB-NO probe, affording a tailored lysosome-targeting NIR fluorescent Lyso-SiRB-NO probe. Inheriting the key advantages of its parent SiRB-NO probe, Lyso-SiRB-NO is a functional probe that is suited for monitoring lysosomal NO with excellent lysosome compatibility. Imaging experiments demonstrated the monitoring of both exogenous and endogenous NO in real time by using the Lyso-SiRB-NO probe.

Synthesis, In Vitro Biological Evaluation, and Molecular Docking of New Triazoles as Potent Antifungal Agents.

Based on the structure of the active site of CYP51 and the structure-activity relationships of azole antifungal compounds that we designed in a previous study, a series of 1-{1-[2-(substitutedbenzyloxy)ethyl]-1H-1,2,3-triazol-4-yl}-2-(2,4-difluorophenyl)-3-(1H-1,2,4-triazol-1-yl)propan-2-ols (6a-n) were designed and synthesized utilizing copper-catalyzed azide-alkyne cycloaddition. Preliminary antifungal tests against eight human pathogenic fungi in vitro showed that all the title compounds exhibited excellent antifungal activities with a broad spectrum in vitro. Molecular docking results indicated that the interaction between the title compounds and CYP51 comprised π-π interactions, hydrophobic interactions, and the narrow hydrophobic cleft.

Resolving the α-glycosidic linkage of arginine-rhamnosylated translation elongation factor P triggers generation of the first ArgRha specific antibody.

A previously discovered posttranslational modification strategy - arginine rhamnosylation - is essential for elongation factor P (EF-P) dependent rescue of polyproline stalled ribosomes in clinically relevant species such as Pseudomonas aeruginosa and Neisseria meningitidis. However, almost nothing is known about this new type of N-linked glycosylation. In the present study we used NMR spectroscopy to show for the first time that the α anomer of rhamnose is attached to Arg32 of EF-P, demonstrating that the corresponding glycosyltransferase EarP inverts the sugar of its cognate substrate dTDP-ß-l-rhamnose. Based on this finding we describe the synthesis of an α-rhamnosylated arginine containing peptide antigen in order to raise the first anti-rhamnosyl arginine specific antibody (anti-ArgRha). Using ELISA and Western Blot analyses we demonstrated both its high affinity and specificity without any cross-reactivity to other N-glycosylated proteins. Having the anti-ArgRha at hand we were able to visualize endogenously produced rhamnosylated EF-P. Thus, we expect the antibody to be not only important to monitor EF-P rhamnosylation in diverse bacteria but also to identify further rhamnosyl arginine containing proteins. As EF-P rhamnosylation is essential for pathogenicity, our antibody might also be a powerful tool in drug discovery.

Near-Infrared Phosphorus-Substituted Rhodamine with Emission Wavelength above 700†nm for Bioimaging.

Phosphorus has been successfully fused into a classic rhodamine framework, in which it replaces the bridging oxygen atom to give a series of phosphorus-substituted rhodamines (PRs). Because of the electron-accepting properties of the phosphorus moiety, which is due to effective σ*-π* interactions and strengthened by the inductivity of phosphine oxide, PR exhibits extraordinary long-wavelength fluorescence emission, elongating to the region above 700 nm, with bathochromic shifts of 140 and 40 nm relative to rhodamine and silicon-substituted rhodamine, respectively. Other advantageous properties of the rhodamine family, including high molar extinction coefficient, considerable quantum efficiency, high water solubility, pH-independent emission, great tolerance to photobleaching, and low cytotoxicity, stay intact in PR. Given these excellent properties, PR is desirable for NIR-fluorescence imaging in vivo.

Matrine derivative WM130 inhibits hepatocellular carcinoma by suppressing EGFR/ERK/MMP-2 and PTEN/AKT signaling pathways.

Matrine, a sophora alkaloid, has been demonstrated to exert antitumor effects on many types of cancer. However, its bioactivity is weak and its potential druggability is low. We modified the structure of matrine and obtained a new matrine derivative, WM130 (C30N4H40SO5F), which exhibited better pharmacological activities than matrine. In this study, we investigated the antitumor activity and the underlying mechanisms of WM130 on hepatocellular carcinoma (HCC) cells in vitro and in vivo, and found that WM130 inhibited the proliferation, invasion, migration and induced apoptosis of HCC cells in a dose-dependent manner. Furthermore, after treatment with WM130, the expressions of p-EGFR, p-ERK, p-AKT, MMP-2 and the ratio of Bcl-2/Bax were significantly down-regulated, whereas the expression of PTEN was increased in HCC cells. Moreover, WM130 inhibited Huh-7 xenograft tumor growth in a dose-dependent manner after intravenous administration. Immunohistochemistry results demonstrated that WM130 treatment resulted in down-regulation of p-EGFR, MMP-2, and Ki67 and up-regulation of PTEN. The findings indicated that WM130 could inhibit cell proliferation, invasion, migration and induced apoptosis in HCC cells by suppressing EGFR/ERK/MMP-2 and PTEN/AKT signaling pathways and may be a novel effective candidate for HCC treatment.

A Novel Matrine Derivative WM130 Inhibits Activation of Hepatic Stellate Cells and Attenuates Dimethylnitrosamine-Induced Liver Fibrosis in Rats.

Activation of hepatic stellate cells (HSCs) is a critical event in process of hepatic fibrogenesis and cirrhosis. Matrine, the active ingredient of Sophora, had been used for clinical treatment of acute/chronic liver disease. However, its potency was low. We prepared a high potency and low toxicity matrine derivate, WM130 (C30N4H40SO5F), which exhibited better pharmacological activities on antihepatic fibrosis. This study demonstrated that WM130 results in a decreased proliferative activity of HSC-T6 cells, with the half inhibitory concentration (IC50) of 68 µM. WM130 can inhibit the migration and induce apoptosis in HSC-T6 cells at both concentrations of 68 µM (IC50) and 34 µM (half IC50). The expression of α-SMA, Collagen I, Collagen III, and TGF-ß1 could be downregulated, and the protein phosphorylation levels of EGFR, AKT, ERK, Smad, and Raf (p-EGFR, p-AKT, p-ERK, p-Smad, and p-Raf) were also decreased by WM130. On the DMN-induced rat liver fibrosis model, WM130 can effectively reduce the TGF-ß1, AKT, α-SMA, and p-ERK levels, decrease the extracellular matrix (ECM) formation, and inhibit rat liver fibrosis progression. In conclusion, this study demonstrated that WM130 can significantly inhibit the activation of HSC-T6 cells and block the rat liver fibrosis progression by inducing apoptosis, suppressing the deposition of ECM, and inhibiting TGF-ß/Smad and Ras/ERK pathways.

Spiroboronate Si-rhodamine as a near-infrared probe for imaging lysosomes based on the reversible ring-opening process.

A cyclic boronate structure was incorporated into Si-rhodamine to design a pH-activatable near-infrared (NIR) probe based on the reversible ring-opening process triggered by H(+). The probe showed general suitability of specific labelling of acidic lysosomes and tracking their pH changes in living cells.

Synthesis and antibacterial activities of novel tyrocidine A glycosylated derivatives towards multidrug-resistant pathogens.

Glycosylation can have a multifaceted impact on the properties and functions of peptides and plays a critical role in interacting with or binding to the target molecules. Herein, based on the previously reported method for macrocyclic glycopeptide synthesis, two series of tyrocidine A glycosylated derivatives (1a-f and 2a-f) were synthesized and evaluated for their antibacterial activities to further study the structure and activity relationships (SAR). Biological studies showed that the synthetic glycosylated derivatives had good antibacterial activities towards methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. SAR studies based on various glycans and linkages were used to enhance the biochemical profile, resulting in the identification of several potent antibiotics, such as 1f, with a great improved therapeutic index than tyrocidine A.

Design, synthesis, and antifungal activities of novel triazole derivatives containing the benzyl group.

In previous studies undertaken by our group, a series of 1-(1H-1,2,4-triazole-1-yl)-2-(2,4-difluorophenyl)-3-substituted-2-propanols (1a-r), which were analogs of fluconazole, was designed and synthesized by click chemistry. In the study reported here, the in vitro antifungal activities of all the target compounds were evaluated against eight human pathogenic fungi. Compounds 1a, 1q, and 1r showed the more antifungal activity than the others.

A novel cancer immunotherapy based on the combination of a synthetic carbohydrate-pulsed dendritic cell vaccine and glycoengineered cancer cells.

Immune tolerance to tumor-associated carbohydrate antigens (TACAs) has severely restricted the usefulness of most TACAs. To overcome this problem, we selected a sialylated trisaccharide TACA, GM3, as a target antigen, and tested a new immunotherapeutic strategy by combining metabolic bioengineering with dendritic cell (DC) vaccination. We engineered cancer cells to express an artificial structure, N-phenylacetyl-D-neuraminic acid, in place of the natural N-acetyl-D-neuraminic acid of GM3 by using N-phenylacetyl-D-mannosamine (ManNPhAc) as a biosynthetic precursor. Next, we selectively targeted the bioengineered cancer cells by vaccination with DCs pulsed with the GM3 N-phenylacetyl derivative. Vaccination with GM3NPhAc-KLH-loaded DCs elicited robust GM3NPhAc-specific T cell-dependent immunity. The results showed that this strategy could significantly inhibit FBL3 tumor growth and prolong the survival of tumor-bearing mice; B16F10 lung metastases could also be reduced. These findings lay out a new strategy for overcoming immune tolerance to TACAs, such as GM3, for the development of effective tumor immunotherapies.