Recent advance of ATP citrate lyase inhibitors for the treatment of cancer and related diseases.

ATP citrate lyase (ACLY), a strategic metabolic enzyme that catalyzes the glycolytic to lipidic metabolism, has gained increasing attention as an attractive therapeutic target for hyperlipidemia, cancers and other human diseases. Despite of continual research efforts, targeting ACLY has been very challenging. In this field, most reported ACLY inhibitors are "substrate-like" analogues, which occupied with the same active pockets. Besides, some ACLY inhibitors have been disclosed through biochemical screening or high throughput virtual screening. In this review, we briefly summarized the cancer-related functions and the recent advance of ACLY inhibitors with a particular focus on the SAR studies and their modes of action. We hope to provide a timely and updated overview of ACLY and the discovery of new ACLY inhibitors.

An Intelligent Laser-Free Photodynamic Therapy Based on Endogenous miRNA-Amplified CRET Nanoplatform.

Laser-free photodynamic therapy (PDT) is a promising noninvasive therapeutic modality for deep-seated tumor, yet is constrained by low efficiency due to the limited stimulation strategies. Herein, a novel miRNA-responsive laser-free PDT was developed through metal-organic frameworks (MOFs)-mediated chemiluminescence resonance energy transfer (CRET) nanoplatform. The photosensitizer chlorin e6 (Ce6)-loaded MOFs were functionalized with hairpin nucleic acids for sensitive responsiveness of tumor biomarker miRNA through catalytic hairpin assembly (CHA), which enabled the amplified assembly of horseradish peroxidase (HRP)-mimicking hemin/G-quadruplex DNAzyme on MOFs. Simultaneously, the on-MOF assembled DNAzymes efficiently catalyzed chemiluminescence reaction to stimulate adjacent Ce6 in the presence of luminol and H2 O2 , thus allowing the CRET-mediated Ce6 luminescence and reactive oxygen species (ROS) generation for self-illuminating PDT. The CRET nanoplatform achieved significant malignant cell apoptosis and tumor inhibition effects without external laser irradiation. It is envisioned that the miRNA-amplified CRET nanoplatform might be a selective and highly efficient antitumor nanomedicine for precise theranostic.

Dual-Signal Cascaded Nucleic Acid Amplification Circuit-Loaded Metal-Organic Frameworks for Accurate and Robust Imaging of Intracellular MicroRNA.

Cascaded signal amplification technologies play an important role in the sensitive detection of lowly expressed biomarkers of interests yet are constrained by severe background interference and low cellular accessibility. Herein, we constructed a metal-organic framework-encapsulating dual-signal cascaded nucleic acid sensor for precise intracellular miRNA imaging. ZIF-8 nanoparticles load and deliver FAM-labeled upstream catalytic hairpin assembly (CHA) and Cy5-modified downstream hybridization chain reaction (HCR) hairpin reactants to tumor cells, enabling visualization of the target-initiated signal amplification process for double-insurance detection of analytes. The pH-responsive ZIF-8 nanoparticles effectively protect DNA hairpins from degradation and allow the release of them in the acid tumor microenvironment. Then, intracellular target miRNAs orderly trigger cascaded nucleic acid signal amplification reaction, of which the exact progress is investigated through the analysis of the fluorescence recovering process of FAM and Cy5. In addition, DNA@ZIF-8 nanoparticles improve measurement accuracy by dual-signal colocalization imaging, effectively avoiding nonspecific false-positive signals and enabling in situ imaging of miRNAs in living cells. A dual-signal colocalization strategy allows accurate target detection in living cells, and DNA@ZIF-8 provides a promising intracellular sensing platform for signal amplification and visual monitoring.

Chemiluminescence resonance energy transfer-based multistage nucleic acid amplification circuits for MiRNA detection with low background.

Chemiluminescence resonance energy transfer (CRET)-based assays have shown great potential in biosensing due to their negligible background autofluorescence, yet are still limited by their low sensitivity and short half-life luminescence. Herein, a multistage CRET-based DNA circuit was constructed with amplified luminescence signals for accurate miRNA detection and fixed reactive oxygen species (ROS) signals for cell imaging. The DNA circuit is designed through an ingenious programmable catalytic hairpin assembly (CHA), hybridization chain reaction (HCR), and the use of DNAzyme to realize target-triggered precise regulation of distance between the donor and acceptor for CRET-mediated excitation of photosensitizers. In detail, the analyte catalyzes the hybridization of CHA reactants, which leads to the assembly of multiple HCR-mediated DNAzyme nanowires. Subsequently, DNAzymes catalyze the oxidation of luminol by H2O2, and the adjacent photosensitizer chlorin e6 (Ce6) anchored on the DNA nanostructure is stimulated by the CRET process, resulting in the amplified long-wavelength luminescence and the generation of single oxygen signals through further energy transfer to oxygen. The biomarker miRNA can be detected with great sensitivity by integrating the recognition module into a universal platform. Furthermore, the DNA circuit enables CRET-mediated intracellular miRNA imaging, by detecting singlet oxygen signals through a ROS probe. The significant amplification effect is attributed to the robust multiple recognition of the target and the guaranteed transduction of the CRET signal through programmable engineering of DNA nanostructures. The CRET-based DNA circuit achieves amplified long-wavelength luminescence for accurate miRNA detection with low background and ROS-mediated signal fixation for cell imaging, making it a promising candidate for early diagnosis and theranostics.

10,11-dehydrocurvularin exerts antitumor effect against human breast cancer by suppressing STAT3 activation.

Aberrant activation of signal transducer and activator of transcription 3 (STAT3) plays a critical role in many types of cancers. As a result, STAT3 has been identified as a potential target for cancer therapy. In this study we identified 10,11-dehydrocurvularin (DCV), a natural-product macrolide derived from marine fungus, as a selective STAT3 inhibitor. We showed that DCV (2-8 µM) dose-dependently inhibited the proliferation, migration and invasion of human breast cancer cell lines MDA-MB-231 and MDA-MB-468, and induced cell apoptosis. In the two breast cancer cell lines, DCV selectively inhibited the phosphorylation of STAT3 Tyr-705, but did not affect the upstream components JAK1 and JAK2, as well as dephosphorylation of STAT3. Furthermore, DCV treatment strongly inhibited IFN-γ-induced STAT3 phosphorylation but had no significant effect on IFN-γ-induced STAT1 and STAT5 phosphorylation in the two breast cancer cell lines. We demonstrated that the α, ß-unsaturated carbonyl moiety of DCV was essential for STAT3 inactivation. Cellular thermal shift assay (CETSA) further revealed the direct engagement of DCV with STAT3. In nude mice bearing breast cancer cell line MDA-MB-231 xenografts, treatment with DCV (30 mg·kg-1·d-1, ip, for 14 days) markedly suppressed the tumor growth via inhibition of STAT3 activation without observed toxicity. Our results demonstrate that DCV acts as a selective STAT3 inhibitor for breast cancer intervention.

Molecular Imaging and In Situ Quantitative Profiling of Fatty Acid Synthase with a Chemical Probe.

Cancer cells rely on fatty acid synthase (FASN), a key enzyme for de novo biosynthesis of long chain fatty acids, to sustain their proliferative potential and drive invasion. Unfortunately, conventional FASN assays are technically inadequate for discerning otherwise elusive FASN activity in complex biological milieux, which has hindered progress in the functional study of FASN and development of its inhibitors. Here, we describe a chemical probe with unprecedented selectivity and sensitivity for the labeling of active FASN in living cells, thus demonstrating a new analytical modality for visualizing endogenous FASN activity and exploring opportunities for drug discovery.

High cell density culture of baker's yeast FX-2 based on pH-stat coupling with respiratory quotient.

The high cell density culture of baker's yeast FX-2 was investigated in a 50 L(A) automatic bioreactor. Herein, it was found firstly that the Crabtree effect clearly existed in batch fermentation with higher glucose content, then the critical initial glucose content range (≤2.00 g L-1 ) was reasonably ascertained to effectively avoid Crabtree effect. In the next fed-batch fermentations with different strategies, the second strategy (maintain ethanol concentration lower than 0.10% and pH around 4.80) was confirmed to be more beneficial to yeast growth than the first strategy (keep reducing sugar not more than 2.00 g L-1 and control steady Carbon/Nitrogen ratio 3.05:1.00). After that, one optimal control strategy (maintain pH around 4.80 and keep respiratory quotient in the range of 0.90-1.00) was constructed to further enhance cell yield. Under an optimal control strategy, four schemes with the aim of achieving pH-stat were compared, and yeast extract instead of other alkaline materials was selected as a better regulator. As a result, 148.37 g L-1 dry cell weight, 38.25 × 108 mL-1 living cells, and 8.24 g L-1  h-1 productivity were harvested, which respectively elevated 23.74%, 135.38%, and 24.47% compared to that obtained under the traditional scheme (regulate pH with ammonia); meanwhile, the maximum oxygen uptake rate and carbon dioxide excretion rate were both more than 250.00 mmol L-1  min-1 .

Influence of the flow field on α-cyclodextrin glycosyltransferase production by Escherichia coli BL21.

The computational fluid dynamics (CFD) software package Fluent was utilized to simulate the flow field of Escherichia coli (E. coli) BL21 fermentation in a 50 L automatic bioreactor for producing α-cyclodextrin glycosyltransferase (α-CGTase) in this study. 4-down-pumping propeller (4DPP), 6-curved-blade disc turbine (6CBDT), and Rushton turbine (RT) were assembled to form eight impeller combinations (C1-C8). Through flow field simulating, four referential impeller combinations, in which C6, C7, and C8 were three layers stirring blades and C1 as a control, were selected to carry out batch fermentation experiments (TC1, TC6, TC7, and TC8) for validation. The correlation analysis between simulation results and experimental measurements indicated that TC6 (tank equipped with C6 impeller combination) exhibited lower enzymatic activity though it had the better mixing effect, fastest oxygen uptake rate (OUR), and maximum specific growth rate (µ) in the initial stage, which was just to the contrary in TC8. It was revealed by next fed-batch fermentation experiments in TC6 and TC8 that TC6 was considered as excellent flow field properties brought about the higher µ of E. coli BL21 and fast acetic acid (HAc) accumulation, which resulting in a serious inhibition on α-CGTase expression and this negative effect could not be removed. As a result, there should be a threshold of HAc accumulation rate which brought about a terrible inhibitory effect on α-CGTase expression. Moreover, the yield of α-CGTase activity reached 231.38 U mL- 1 in TC8, which elevated 31.74% compared to that obtained in TC1.

Aspergoterpenins A⁻D: Four New Antimicrobial Bisabolane Sesquiterpenoid Derivatives from an Endophytic Fungus Aspergillus versicolor.

Aspergoterpenins A⁻D (1⁻4), four new bisabolane sesquiterpenoid derivatives, were obtained from the endophytic fungus, Aspergillus versicolor, together with eight known compounds (5⁻12), and their structures were elucidated by a comprehensive analysis of their NMR (Nuclear Magnetic Resonance), MS (Mass Spectrum) and CD (Circular Dichroism) spectra. Aspergoterpenin A (1) was the first example with a characteristic ketal bridged-ring part in the degraded natural bisabolane-type sesquiterpene structures. The compounds 1⁻12 displayed no significant activities against four cancer cell lines (A549, Caski, HepG2 and MCF-7). Further, the antimicrobial activities to Erwinia carotovora sub sp. Carotovora were evaluated, and the results showed that compounds 1⁻12 displayed antimicrobial activities with MIC values ranging from 15.2 to 85.2 µg/mL.

Penicitroamide, an Antimicrobial Metabolite with High Carbonylization from the Endophytic Fungus Penicillium sp. (NO. 24).

Penicitroamide (1), a new metabolite with a new framework, was isolated from the ethyl acetate extract of the PDB (Potato Dextrose Broth) medium of Penicillium sp. (NO. 24). The endophytic fungus Penicillium sp. (NO. 24) was obtained from the healthy leaves of Tapiscia sinensis Oliv. The structure of penicitroamide (1) features a bicyclo[3.2.1]octane core unit with a high degree of carbonylization (four carbonyl groups and one enol group). The chemical structure of penicitroamide (1) was elucidated by analysis of 1D-, 2D-NMR and MS data. In bioassays, penicitroamide (1) displayed antibacterial potency against two plant pathogens, Erwinia carotovora subsp. Carotovora (Jones) Bersey, et al. and Sclerotium rolfsii Sacc. with MIC50 at 45 and 50 µg/mL. Compound 1 also showed 60% lethality against brine shrimp at 10 µg/mL. Penicitroamide (1) exhibited no significant activity against A549, Caski, HepG2 and MCF-7 cells with IC50 > 50 µg/mL. Finally, the possible biosynthetic pathway of penicitroamide (1) was discussed.

Effect of Culture Conditions on Metabolite Production of Xylaria sp.

Seeking a strategy for triggering the cryptic natural product biosynthesis to yield novel compounds in the plant-associated fungus Xylaria sp., the effect of culture conditions on metabolite production was investigated. A shift in the production of five known cytochalasin-type analogues 1-5 to six new α-pyrone derivatives, xylapyrones A-F (compounds 6-11), from a solid to a liquid medium was observed. These compounds were identified by analysis of 1D and 2D NMR and HRMS data. Compounds 1-3 showed moderate cytotoxicity against HepG2 and Caski cancer cell lines with IC50 values ranging from 25 to 63 µM and compounds 4-11 were found to be inactive, with IC50 values>100 µM.

Pestalafuranones F-J, five new furanone analogues from the endophytic fungus Nigrospora sp. BM-2.

Five new 2(5H)-furanone-type derivatives, pestalafuranones F-J (compounds 3-7), together with two known compounds, pestalafuranones A (1) and B (2), were isolated from the ethyl acetate extract from the fermentation broth of the endophytic fungus Nigrospora sp. BM-2 in a hypersaline medium. The structures of these metabolites were elucidated by EIMS, HREIMS and NMR spectroscopic data. Compounds 1-7 exhibited no cytotoxic activities against the MDA-MB-231 and Caski cancer cell lines.

Protoberberine isoquinoline alkaloids from Arcangelisia gusanlung.

HPLC-DAD-directed isolation and purification of the methanol extract of stems of Arcangelisia gusanlung H. S. Lo. led to the isolation of a new protoberberine alkaloid, gusanlung E (1), along with fourteen known derivatives 2-15, seven of which were obtained from the genus Arcangelisia for the first time. The structures and absolute stereochemistry of these compounds were elucidated on the basis of spectroscopic analyses, including 1D and 2D NMR, mass spectrometry, and CD analyses. Gusanlung E (1) expressed weak cytotoxic activity against the SGC 7901 cell line with an IC50 value of 85.1 µM.

Dehydrocurvularin-loaded mPEG-PLGA nanoparticles for targeted breast cancer drug delivery: preparation, characterization, in vitro, and in vivo evaluation.

Dehydrocurvularin (DCV) is a promising lead compound for anti-cancer therapy. Unfortunately, the development of DCV-based drugs has been hampered by its poor solubility and bioavailability. Herein, we prepared a DCV-loaded mPEG-PLGA nanoparticles (DCV-NPs) with improved drug properties and therapeutic efficacy. The spherical and discrete particles of DCV-NPs had a uniform diameter of 101.8 ± 0.45 nm and negative zeta potential of -22.5 ± 1.12 mV (pH = 7.4), and its entrapment efficiency (EE) and drug loading (DL) were ∼53.28 ± 1.12 and 10.23 ± 0.30%, respectively. In vitro the release of DCV-NPs lasted for more than 120 h in a sustained-release pattern, its antiproliferation efficacy towards breast cancer cell lines (MCF-7, MDA-MB-231, and 4T1) was better than that of starting drug DCV, and it could be efficiently and rapidly internalised by breast cancer cells. In vivo DCV-NPs were gradually accumulated in tumour areas of mice and significantly suppressed tumour growth. In summary, loading water-insoluble DCV onto nanoparticles has the potential to be an effective agent for breast cancer therapy with injectable property and tumour targeting capacity.

Mechanism of Phloretin Accumulation in Malus hupehensis Grown at High Altitudes: Evidence from Quantitative 4D Proteomics.

Phloretin is a natural dihydrochalcone (DHC) that exhibits various pharmacological and therapeutic activities. Malus hupehensis Rehd. (M. hupehensis) is widely planted in the middle of China and its leaves contain an extremely high content of phloridzin, a glycosylated derivative of phloretin. In the present study, we observed a significant increase in phloretin content in the leaves of M. hupehensis planted at high altitudes. To investigate the mechanisms of phloretin accumulation, we explored changes in the proteome profiles of M. hupehensis plants grown at various altitudes. The results showed that at high altitudes, photosynthesis- and DHC biosynthesis-related proteins were downregulated and upregulated, respectively, leading to reduced chlorophyll content and DHC accumulation in the leaves. Moreover, we identified a novel phloridzin-catalyzing glucosidase whose expression level was significantly increased in high-altitude-cultivated plants. This work provided a better understanding of the mechanism of phloretin accumulation and effective and economic strategies for phloretin production.

Discovery of Artemisinins as Microsomal Prostaglandins Synthase-2 Inhibitors for the Treatment of Colorectal Cancer via Chemoproteomics.

Colorectal cancer remains the second leading cause of cancer-related mortalities worldwide. While artemisinin (ART), a key active compound from the traditional Chinese medicinal herb Artemisia annua, has been recognized for its antiproliferative activity against colon cancer cells, its underlying molecular underpinnings remain elusive. Whereas promiscuity of heme-dependent alkylating of macromolecules, mainly proteins, has been seen pivotal as a universal and primary mode of action of ART in cancer cells, accumulating evidence suggests the existence of unique targets and mechanisms of actions contingent on cell or tissue specificities. Here, we employed photoaffinity probes to identify the specific targets responsible for ART's anti-colon cancer actions. Upon validation, microsomal prostaglandins synthase-2 emerged as a specific and reversible target of ART in HCT116 colorectal cancer cells, whose inhibition resulted in reduced cellular prostaglandin E2 biosynthesis and cell growth. Our discovery opens new opportunities for pharmacological treatment of colon cancer.

Citrus polymethoxyflavones degrade estrogen receptor-alpha (ERα) and combine with tamoxifen for the treatment of estrogen receptor-positive breast cancer.

Estrogen receptor-positive (ER+) breast cancer seriously endangers the women's physical and mental health worldwide and ER targeting therapy is vital. Here, we found that a citrus polymethoxyflavones (PMFs)-rich hydrolysate (C-H) and its major components (nobiletin and 3-methoxynobiletin) potently degrade ERα protein via the ubiquitin-proteasome pathway, thereby impairing the proliferation of ER+ breast cancer cells. Moreover, our study exhibited that C-H combined with tamoxifen (TAM) inhibited the cell proliferation of ER+ breast cancer in vitro. It was further confirmed that C-H decreased tumor growth of ER+ breast cancer in tumor-bearing 129 mice in vivo and improved the efficacy of tamoxifen. Our study revealed that the citrus PMFs have potential applications as pharmaceutical and healthcare products in breast cancer treatment by targeting ERα protein degradation.

Review of 10,11-Dehydrocurvularin: Synthesis, Structural Diversity, Bioactivities and Mechanisms.

10,11-Dehydrocurvularin is a natural benzenediol lactone (BDL) with a 12-membered macrolide fused to a resorcinol ring produced as a secondary metabolite by many fungi. In this review, we summarized the pieces of literature regarding biosynthesis, chemical synthesis, biological activities, and assumed work mechanisms of 10,11-dehydrocurvularin, which presented a potential for agricultural and pharmaceutical uses.

Chemoproteomic profiling reveals celastrol as a potential modulator of cholesterol signaling.

We report a quantitative chemoproteomic approach that utilizes a clickable photoreactive probe for global profiling of celastrol targets, which may significantly improve the current understanding of celastrol's mode of action.

Characterization of precipitation from citrus vinegar during ageing: chemical constituents, formation mechanism and anti-proliferative effect.

Precipitation formation commonly occurs in the ageing step of fermented citrus vinegar. Hitherto, the chemical characteristics and biological properties of precipitates remain unveiled. This study focused on investigating the chemical profile, formation mechanism and biological repurposing of precipitates. Nine principal components, two flavonoid glycosides and their aglycones along with five polymethoxyflavones (PMFs), were identified from a methanol extract of precipitates. Using hydrolysis models, we demonstrated that insoluble aglycones were generated through the breakage of glycosidic bonds in flavonoid glycosides under acidic condition. Moreover, soluble bound-PMFs were destroyed by yeast-acid hybrid catalysis to release insoluble free-PMFs to form precipitates. A methanol extract of precipitates exhibited a potent anti-proliferative effect on MCF-7 cells (IC50 = 0.032 µg µL-1) via inhibiting tubulin polymerization. This study will be helpful for the food industry to aid optimizing citrus vinegar brewing and for reutilizing precipitates for functional foods and health products. Furthermore, it also provides a green strategy of PMFs enrichment from citrus using an enzyme-acid hybrid system.