A Very Deep Graph Convolutional Network for 13C NMR Chemical Shift Calculations with Density Functional Theory Level Performance for Structure Assignment.

Nuclear magnetic resonance (NMR) chemical shift calculations are powerful tools for structure elucidation and have been extensively employed in both natural product and synthetic chemistry. However, density functional theory (DFT) NMR chemical shift calculations are usually time-consuming, while fast data-driven methods often lack reliability, making it challenging to apply them to computationally intensive tasks with a high requirement on quality. Herein, we have constructed a 54-layer-deep graph convolutional network for 13C NMR chemical shift calculations, which achieved high accuracy with low time-cost and performed competitively with DFT NMR chemical shift calculations on structure assignment benchmarks. Our model utilizes a semiempirical method, GFN2-xTB, and is compatible with a broad variety of organic systems, including those composed of hundreds of atoms or elements ranging from H to Rn. We used this model to resolve the controversial J/K ring junction problem of maitotoxin, which is the largest whole molecule assigned by NMR calculations to date. This model has been developed into user-friendly software, providing a useful tool for routine rapid structure validation and assignation as well as a new approach to elucidate the large structures that were previously unsuitable for NMR calculations.

Discovery of novel chloropyramine-cinnamic acid hybrids as potential FAK inhibitors for intervention of metastatic triple-negative breast cancer.

To search for novel focal adhesion kinase (FAK) inhibitors for intervention of metastatic triple-negative breast cancer (TNBC), a series of hybrids 7a-s from chloropyramine and cinnamic acid analogs were designed, synthesized and biologically evaluated. The most active compound 7d could potently inhibit the proliferation, invasion and migration of TNBC cells in vitro. The docking analysis of 7d was performed to elucidate its possible binding modes to focal adhesion targeting (FAT) domain of FAK scaffold. Further mechanism studies indicated the ability of 7d in disrupting Y925 autophosphorylation of FAK, reducing formation of focal adhesions (FAs) and stress fibers (SFs) as well as inducing apoptosis of TNBC cells. Together, 7d is a novel FAK inhibitor to inhibit the essential nonkinase scaffolding function of FAK via binding FAT domain and may be worth studying further for intervention of TNBC.

Identification of a new natural biflavonoids against breast cancer cells induced ferroptosis via the mitochondrial pathway.

Breast cancer is one of the major malignant tumors in females, and currently, recurrence and metastasis are the main obstacles preventing effective breast cancer treatment. Biflavonoids of secondary metabolites from plants are excellent anticancer agents to fight sensitive and resistant breast cancer cell lines. In this study, six C-3'-C-6″ biflavonoids, including one new robustaflavone A (1, RF-A) and five known robustaflavone derivatives (2-6), were isolated from Selaginella trichoclada for the first time. We aimed to evaluate the inhibitory effects of compounds 1-6 against human breast cancer MCF-7 cells. Among the six compounds, RF-A showed the strongest activity, decreasing cell viability with an IC50 value of 11.89 µΜ. Furthermore, RF-A strikingly induced MCF-7 nonapoptotic cell death through ferroptosis by enhancing the expression of VDAC2 channels and reducing the expression of Nedd4 E3 ubiquitin ligase, leading to lipid peroxidation and ROS production. The results suggested that RF-A has potential as a novel breast cancer treatment through its regulation of the mitochondrial VDAC2 and Nedd4 pathways.

Rhytidhyesters A - D, 4 New Chlorinated Cyclopentene Derivatives from the Endophytic Fungus Rhytidhysteron sp. BZM-9.

Four new chlorinated cyclopentene derivatives, rhytidhyesters A - D (1:  - 4: ), were isolated from Rhytidhysteron sp. BZM-9, an endophytic fungus from Leptospermum brachyandrum. The planar structures of compounds 1:  - 4: were mainly elucidated by 1D, 2D NMR, and HRESIMS data. Their absolute configurations were established by X-ray crystallographic analysis, quantum chemical 13C NMR, and electronic circular dichroism calculations. Compounds 1: and 2: are a pair of epimers. Moreover, all the isolated compounds were evaluated for cytotoxic activities against 3 human colon cancer cell lines (SW620, HT29, SW480) and antimicrobial activity against Staphylococcus aureus. All compounds exhibited weak to moderate antiproliferative activities with IC50 values ranging from 15.4 to 37.7 µM but were inactive against S. aureus.

Triterpenoids with antiproliferative activities from the twigs and leaves of Melaleuca linariifolia.

One new pentacyclic triterpenoid, urs-12,16-dien-3-one (1), together with twelve known pentacyclic triterpenoids (2‒13), were isolated from the twigs and leaves of Melaleuca linariifolia. Their structures were characterized by their 1D- and 2 D-NMR spectra analysis and mass spectra studies. Furthermore, all isolated compounds were tested the inhibitory effect on proliferation of six human cancer cell lines in vitro, including NCI-H441, NCI-H460, A549, SKOV3, hela, and caki-1 cells. Among them, compounds 3, 5, 7, 9, 12, and 13 exhibited moderate antiproliferative activities with IC50 values ranging from 3.85 to 33.31 µM.

Rhytidhylides A and B, Two New Phthalide Derivatives from the Endophytic Fungus Rhytidhysteron sp. BZM-9.

Two new phthalide derivatives, rhytidhylides A (1) and B (2), together with ten known compounds (3-12) were isolated from cultures of Rhytidhysteron sp. BZM-9, an endophyte isolated from the leaves of Leptospermum brachyandrum. Their structures were identified by an extensive analysis of NMR, HRESIMS, ECD, and through comparison with data reported in the literature. In addition, the cytotoxic activities against two human hepatoma cell lines (HepG2 and SMMC7721) and antibacterial activities against MRSA and E. coli were evaluated.

Biflavonoids from Selaginella doederleinii as Potential Antitumor Agents for Intervention of Non-Small Cell Lung Cancer.

Four new biflavonoids (1-4) were isolated from Selaginella doederleinii together with a known biflavonoid derivative (5). Their structures contained a rare linker of individual flavones to each other by direct C-3-O-C-4''' bonds, and were elucidated by extensive spectroscopic data, including HRESIMS, NMR and ECD data. All isolates significantly inhibited the proliferation of NSCLC cells (IC50 = 2.3-8.4 µM) with low toxicity to non-cancer MRC-5 cells, superior to the clinically used drug DDP. Furthermore, the most active compound 3 suppressed XIAP and survivin expression, promoted upregulation of caspase-3/cleaved-caspase-3, as well as induced cell apoptosis and cycle arrest in A549 cells. Together, our findings suggest that 3 may be worth studying further for intervention of NSCLC.

Serratane triterpenoids from Lycopodium complanatum and their anti-cancer and anti-inflammatory activities.

Phytochemical investigation of the ethyl acetate fraction of Lycopodium complanatum led to eight new serratane triterpenoids (lycomplanatums A-H, 1-8), along with five known analogues (9-13). Their structures were elucidated by extensive spectroscopic methods, including 1D/2D NMR, HRESIMS, and DFT GIAO 13C NMR calculation. Among them, compounds 2 and 13 showed moderate antiproliferative effects against seven human cancer cell lines, especially for MCF-7 with IC50 values of 13.8-44.7 µM. Additionally, the compounds were screened for anti-inflammatory effects based on their inhibitory activities of nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 cells, and compounds 2 and 13 diminished NO production more potently than others in a concentration-dependent manner.

Two New Abietane Diterpenoids from Selaginella moellendorffii Hieron.

Two new abietane diterpenoids, (3S,5R,10S)-3-hydroxy-12-O-demethyl-11-deoxy-19(4→3)-abeo-cryptojaponol, 12,19-dihydroxyabieta-8,11,13-trien-7-one, were isolated from Selaginella moellendorffii Hieron., together with one known abietane diterpenoid and four known tetracyclic triterpenoids. Their structures were characterized by their 1D- and 2D-NMR, ECD and mass spectral studies. All compounds were tested for their inhibitory effects on proliferation of three human cancer cells (human non-small-cell lung carcinoma cell lines A549 and human breast adenocarcinoma cell lines MDA-MB-231 and MCF-7) in vitro. Among them, three compounds displayed modest cytotoxic activities against the above three human cancer cell lines with IC50 values ranging from 16.28 to 40.67 µM.

Selective geranylation of biflavonoids by Aspergillus terreus aromatic prenyltransferase (AtaPT).

Prenylation increases the bioactivity of flavonoids. Herein, we report the first examples of regioselective enzymatic geranylation of biflavonoids using Aspergillus terreus aromatic prenyltransferase (AtaPT). For biflavonoids 1-3 dimerized through a diphenyl linkage, geranylation occurs at the hydrogen bond involving C5''-OH group, which is less chemically accessible than other OH groups in the molecule. This study would be referential for developing green synthetic solutions for prenylated biflavonoids.

High-Throughput Screening of Stapled Helical Peptides in Drug Discovery.

Therapeutic peptides have revolutionized treatment for a number of human diseases. In particular, the past two decades have witnessed rapid progress of stapled helical peptides in drug discovery. Stapled helical peptides are chemically modified and constrained in their bioactive α-helical conformation. Compared to unstabilized linear peptides, stapled helical peptides exhibit superior binding affinity and selectivity, enhanced membrane permeability, and improved metabolic stability, presenting exciting promise for targeting otherwise challenging protein-protein interfaces. In this Perspective, we summarize recent applications of high-throughput screening technologies for identification of potent stapled helical peptides with optimized binding properties. We expect to provide a broad reference to accelerate the development of stapled helical peptides as the next generation of therapeutic peptides for various human diseases.

Design, synthesis and evaluation of nitric oxide releasing derivatives of 2,4-diaminopyrimidine as novel FAK inhibitors for intervention of metastatic triple-negative breast cancer.

To search for novel medicines for intervention of triple-negative breast cancer (TNBC), a series of phenylsulfonyl furoxan-based 2,4-diaminopyrimidine derivatives (8a-t) were designed and synthesized based on blocking FAK-mediated signaling pathways through both kinase-dependent and -independent manners. The most active compound 8f not only significantly inhibited FAK kinase activity (IC50 = 27.44 nM), displayed potent inhibitory effects on the proliferation (IC50 = 0.126 µM), invasion and migration of MDA-MB-231 cells, superior to the most widely studied FAK inhibitor, TAE226, bearing 2,4-diaminopyrimidine, but also released high levels of NO, contributing to blockage of FAK mediated-signaling pathways by upregulating of p53 as well as suppressing the Y397 phosphorylation and its downstream effectors, including p-Akt, MMP-2, and MMP-9 via kinase-independent manner, leading to apoptosis induction and decrease of FAs and SFs in TNBC cells. Importantly, 8f inhibited the lung metastasis of TNBC in vivo. Together, 8f may serve as a promising candidate for the treatment of metastatic TNBC.

Three new metabolites from the endophyte Fusarium proliferatum T2-10.

One new cyclopeptide, cyclo-(L-Trp-L-Phe-L-Phe) (1), one new 2-pyridone derivative, fusarone A (3), and one new natural indole derivative, ethyl 3-indoleacetate (4), along with six known compounds were isolated from the endophytic fungus Fusarium proliferatum T2-10. The planar structures of three new compounds were identified by spectral methods including 1D and 2D NMR techniques, and the absolute configuration of compound 1 was elucidated by Marfey-MS method. In addition, all compounds were evaluated for their cytotoxic and antibacterial activities in vitro. Compound 2 showed remarkable cytotoxic activities against two human hepatoma cell lines SMMC7721 and HepG2 with IC50 values of 5.89 ± 0.74 and 6.16 ± 0.52 µM, and showed moderate antibacterial activities against Staphylococcus aureus and Enterococcus faecalis with MIC values of 7.81 and 15.62 µg/mL, respectively.

Pseudocercones A-C, three new polyketide derivatives from the endophytic fungus Pseudocercospora sp. TSS-1.

Chemical investigation of an EtOAc extract of the endophytic fungus Pseudocercospora sp. TSS-1 led to the isolation of three new polyketide derivatives, including one benzophenon derivative (1), two spirocyclic polyketides (4 and 5), along with four known compounds (2, 3, 6 and 7). Their structures and the absolute configurations were characterized by means of NMR, HRESIMS, 13C NMR and theoretical electronic circular dichroism calculations. Furthermore, all compounds were evaluated for their antibacterial activity against four microbial pathogens (Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli), and compounds 1, 2, 3 and 5 displayed significant selective antibacterial activity against S. aureus with MIC values ranging from 3.9 to 7.8 µg/mL.

Diaportones A-C: Three New Metabolites From Endophytic Fungus Diaporthe foeniculina BZM-15.

Phytochemical investigation of Diaporthe foeniculina BZM-15 led to one new γ-butyrolactone derivative, diaportone A (1), one cyclopentenone derivative, diaportone B (3), and one monoterpene derivative, diaportone C (5), along with six known compounds (2, 4, and 6-9). Their structures as well as the absolute configurations were characterized by means of NMR, HRESIMS, and ECD spectroscopy and quantum chemistry calculation, respectively. Furthermore, all compounds were evaluated for their cytotoxic activity and antibacterial activity, and compounds 7 and 8 displayed significant antiproliferative effects on three human cancer cell lines (SF-268, MCF-7, and HepG2) with IC50 values ranging from 3.6 to 15.8 µM.

Design, Synthesis, and Biological Evaluation of Organic Nitrite (NO2-) Donors as Potential Anticerebral Ischemia Agents.

The treatment of ischemic stroke (IS) remains a big challenge in clinics, and it is urgently needed to develop novel, safe, and effective medicines against IS. Here, we report the design, synthesis, and biological evaluation of organic NO2- donors as potential agents for the treatment of IS. The representative compound 4a was able to slowly generate low concentrations of NO2- by reaction with a thiol-containing nucleophile, and the NO2- was selectively converted into NO under ischemic/hypoxia conditions to protect primary rat neurons from oxygen-glucose deprivation and recovery (OGD/R)-induced cytotoxicity by enhancing the Nrf2 signaling and activating the NO/cGMP/PKG pathway. Treatment with 4a at 2 h before or after ischemia mitigated the ischemia/reperfusion-induced brain injury in middle cerebral artery occlusion (MCAO) rats by producing NO and enhancing Nrf2 signaling. Furthermore, 4a significantly promoted endothelial cell proliferation and angiogenesis within the ischemic penumbra. Our findings suggest that this type of NO2- donors, like 4a, may be valuable to fight IS and other ischemic diseases.

A novel Apigenin derivative suppresses renal cell carcinoma via directly inhibiting wild-type and mutant MET.

MET, the receptor of hepatocyte growth factor (HGF), is a driving factor in renal cell carcinoma (RCC) and also a proven drug target for cancer treatment. To improve the activity and to investigate the mechanisms of action of Apigenin (APG), novel derivatives of APG with improved properties were synthesized and their activities against Caki-1 human renal cancer cell line were evaluated. It was found that compound 15e exhibited excellent potency against the growth of multiple RCC cell lines including Caki-1, Caki-2 and ACHN and is superior to APG and Crizotinib. Subsequent investigations demonstrated that compound 15e can inhibit Caki-1 cell proliferation, migration and invasion. Mechanistically, 15e directly targeted the MET kinase domain, decreased its auto-phosphorylation at Y1234/Y1235 and inhibited its kinase activity and downstream signaling. Importantly, 15e had inhibitory activity against mutant MET V1238I and Y1248H which were resistant to approved MET inhibitors Cabozantinib, Crizotinib or Capmatinib. In vivo tumor graft study confirmed that 15e repressed RCC growth through inhibition of MET activation. These results indicate that compound 15e has the potential to be developed as a treatment for RCC, and especially against drug-resistant MET mutations.

Seladelicatulasine A-G, C27 steroidal glycosides with cholinesterase inhibitory activities from Selaginella delicatula.

Seven undescribed C27 steroidal glycosides, Seladelicatulasine A-G, including six cholestanol glycosides and one spirostanol glycoside, were isolated from Selaginella delicatula. Their structures were elucidated by 1D/2D NMR spectra and HRESIMS analyses. The absolute configurations of the sugars were determined by enzymatic hydrolysis and GC/MS analyses. These cholestanol glycosides were isolated from the family Selaginellaceae for the first time. Seladelicatulasine F is characterized as a rare B-5,6-secosteroid. In addition, all the compounds were evaluated for their inhibitory activities against cholinesterase (AChE/BChE) and monoamine oxidase (MAO-A/MAO-B). These steroidal glycosides displayed selective inhibition activities on cholinesterase. Seladelicatulasine A, B and E inhibited the AChE activity with IC50 values of 0.31, 0.09, and 0.04 µM, respectively. Seladelicatulasine A and F showed the strongest inhibition activity on BChE with IC50 values of 0.37 and 0.65 µM, respectively.

Extracts of Cordyceps sinensis inhibit breast cancer growth through promoting M1 macrophage polarization via NF-κB pathway activation.

ETHNOPHARMACOLOGICAL RELEVANCE: Cordyceps sinensis is a traditional Chinese medicine. It is widely reported that Cordyceps sinensis has inhibitory effect on tumor growth and immunoregulation effect on macrophages. However, the exact mechanism of Cordyceps sinensis on macrophage polarization in tumor progression is not known. AIM OF STUDY: We aimed to investigate the role of extracts of Cordyceps sinensis on macrophage polarization and its underlying mechanism in antitumor activity. MATERIALS AND METHODS: The 4T1 orthotopic xenograft mouse model and immunohistochemical staining were used to investigate the effect of Cordyceps sinensis on breast tumor and the change of the macrophages phenotype in the tumor, respectively. A 3D co-culture assay was used to confirm the activity in vitro. Measurement of cytokines and NO, quantitative real-time PCR and flow cytometry assays were used to investigate the effect of Cordyceps sinensis on the macrophage polarization in vitro. The mechanism of the effect of Cordyceps sinensis on macrophages was investigated by using western blot assays. RESULTS: In the orthotopic mouse tumor model, Cordyceps sinensis inhibited the 4T1 tumor growth in a dose dependent manner, and the immunohistochemical staining analysis showed that there is a positive correlation between tumor growth inhibition and macrophage M1-like polarized phenotype. The cytokines and NO measurement, quantitative real-time PCR assay and flow cytometry assays confirmed that Cordyceps sinensis could promote macrophage differentiation toward the M1 phenotype. The 3D co-culture assay and western blot assay showed that Cordyceps sinensis could inhibit tumor growth by promoting macrophage polarization and enhance its activity by activating the NF-κB signaling pathway. CONCLUSION: These findings suggest that Cordyceps sinensis could potently suppress TNBC progression by promoting M1 phenotypic differentiation of macrophages via activation NF-κB signaling pathway in tumor microenvironment.

Olean-28,13b-olide 2 plays a role in cisplatin-mediated apoptosis and reverses cisplatin resistance in human lung cancer through multiple signaling pathways.

Lung cancer, similar to other chronic diseases, occurs due to perturbations in multiple signaling pathways. Mono-targeted therapies are not ideal since they are not likely to be effective for the treatment and prevention of lung cancer, and are often associated with drug resistance. Therefore, the development of multi-targeted agents is required for novel lung cancer therapies. Thioredoxin reductase (TrxR or TXNRD1) is a pivotal component of the thioredoxin (Trx) system. Various types of tumor cells are able to overexpress TrxR/Trx proteins in order to maintain tumor survival, and this overexpression has been shown to be associated with clinical outcomes, including irradiation and drug resistance. Emerging evidence has indicated that oleanolic acid (OA) and its derivatives exhibit potent anticancer activity, and are able to overcome drug resistance in cancer cell lines. In the present study, it was demonstrated that a novel synthesized OA family compound, olean-28,13b-olide 2 (OLO-2), synergistically enhanced cisplatin (CDDP)-mediated apoptosis, led to the activation of caspase-3 and the generation of reactive oxygen species (ROS), induced DNA damage, and inhibited the activation of the extracellular-signal-regulated kinase (ERK), signal transducer and activator of transcription 3 (STAT3), AKT and nuclear factor-κB (NF-κB) pathways in human multidrug-resistant A549/CDDP lung adenocarcinoma cells. Subsequent analyses revealed that OLO-2 inhibited P-glycoprotein (P-gp or ABCB1) and TrxR by reducing their expression at the protein and mRNA levels, and by suppressing P-gp ATPase and TrxR activities. Further biological evaluation indicated that OLO-2 significantly reduced Trx and excision repair cross-complementary1 (ERCC1) protein expression and significantly inhibited the proliferation of drug-sensitive (A549) and multidrug-resistant (A549/CDDP) non-small cell lung cancer (NSCLC) cells, but had no effect on non-tumor lung epithelial-like cells. In addition, the present study demonstrated, for the first time, to the best of our knowledge, that overexpressing or knocking down TrxR in NSCLC cells enhanced or attenuated, respectively, the resistance of NSCLC cells against CDDP, which indicated that TrxR plays an important role in CDDP resistance and functions as a protector of NSCLC against chemotherapeutic drugs. OLO-2 treatment also exhibited up to 4.6-fold selectivity against human lung adenocarcinoma cells. Taken together, the results of the present study shed light on the drug resistance-reversing effects of OLO-2 in lung cancer cells.