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Planta Medica Jun 2024Many polyprenylated acylphloroglucinols with fascinating chemical structures and intriguing biological activities have been identified as key to phytochemicals isolated...
Many polyprenylated acylphloroglucinols with fascinating chemical structures and intriguing biological activities have been identified as key to phytochemicals isolated from , and related genera. In the present work, two chiral, tautomeric, highly-oxygenated polyprenylated acylphloroglucinols tethered with acyl and prenyl moieties on a bicyclo[3.3.1]nonanetrione core were isolated from the 95% ethanolic extract of fruit. The structures of both compounds were elucidated based on the NMR and MS data with ambiguity in the exact position of the enol and keto functions at C-1 and C-3 of the core structure. The structures of both polyprenylated acylphloroglucinols were established as a structurally revised guttiferone J and the new -guttiferone J with the aid of gauge-independent atomic orbital NMR calculations, CP3 probability analyses, specific rotation calculations, and electronic circular dichroism calculations in combination with the experimental data. The structures of both compounds resemble hyperforin, a potent activator of the human pregnane X receptor. As expected, both compounds showed strong pregnane X receptor activation at 10 µM [7.1-fold (guttiferone J) and 5.0-fold (-guttiferone J)], explained by a molecular docking study, necessitating further in-depth investigation to substantiate the herb-drug interaction potential of upon co-administration with pharmaceutical drugs.
Topics: Garcinia; Magnetic Resonance Spectroscopy; Molecular Structure; Fruit; Benzophenones; Plant Extracts; Phytochemicals; Phloroglucinol; Humans
PubMed: 38843801
DOI: 10.1055/a-2232-4755 -
Drug Metabolism and Disposition: the... Jun 2024This research aimed to clarify the impacts of cannflavin-C on angiotensin II (Ang II)-induced cardiac hypertrophy and their potential role in modulating cytochrome P450...
This research aimed to clarify the impacts of cannflavin-C on angiotensin II (Ang II)-induced cardiac hypertrophy and their potential role in modulating cytochrome P450 1B1 (CYP1B1) and arachidonic acid (AA) metabolites. Currently there is no evidence to suggest that cannflavin-C; a prenylated flavonoid, has any significant effects on the heart or cardiac hypertrophy. The metabolism of arachidonic acid (AA) into midchain hydroxyeicosatetraenoic acids (HETEs), facilitated by CYP1B1 enzyme, plays a role in the development of cardiac hypertrophy which is marked by enlarged cardiac cells. Adult human ventricular cardiomyocytes cell line (AC16) were cultured and exposed to cannflavin-C in the presence and absence of Ang II. The assessment of mRNA expression pertaining to cardiac hypertrophic markers and CYPs was conducted via real-time polymerase chain reaction (PCR) while the quantification of CYPs protein levels was carried out through western blot analysis. Ang II induced hypertrophic markers myosin heavy chain (β/α-MHC), atrial natriuretic peptide (ANP), and brain natriuretic peptide (BNP) and increased cell surface area, while cannflavin-C mitigated these effects. Gene and protein expression analysis revealed that cannflavin-C downregulated CYP1B1 gene expression, protein level as well as the enzyme activity assessed by 7-methoxyresorufin O-deethylase (MROD). Arachidonic acid metabolites analysis, using LC-MS/MS, demonstrated that Ang II increased midchain (R/S)-HETEs concentrations, which were attenuated by cannflavin-C. This study provides novel insights into the potential of cannflavin-C in modulating arachidonic acid metabolites and attenuating Ang II-induced cardiac hypertrophy, highlighting the importance of this compound as potential therapeutic agents for cardiac hypertrophy. This study demonstrates that cannflavin-C offers protection against cellular hypertrophy induced by Ang II. The significance of this research lies in its novel discovery, which elucidates a mechanistic pathway involving the inhibition of CYP 1B1 by cannflavin-C. This discovery opens up new avenues for leveraging this compound in the treatment of heart failure.
PubMed: 38839111
DOI: 10.1124/dmd.124.001705 -
Angewandte Chemie (International Ed. in... Jun 2024Prenylation of peptides is widely observed in the secondary metabolites of diverse organisms, granting peptides unique chemical properties distinct from proteinogenic...
Prenylation of peptides is widely observed in the secondary metabolites of diverse organisms, granting peptides unique chemical properties distinct from proteinogenic amino acids. Discovery of prenylated peptide agents has largely relied on isolation or genome mining of naturally occurring molecules. To devise a platform technology for de novo discovery of artificial prenylated peptides targeting a protein of choice, here we have integrated the thioether-macrocyclic peptide (teMP) library construction/selection technology, so-called RaPID (Random nonstandard Peptides Integrated Discovery) system, with a Trp-C3-prenyltransferase KgpF involved in the biosynthesis of a prenylated natural product. This unique enzyme exhibited remarkably broad substrate tolerance, capable of modifying various Trp-containing teMPs to install a prenylated residue with tricyclic constrained structure. We constructed a vast library of prenylated teMPs and subjected it to in vitro selection against a phosphoglycerate mutase. This selection platform has led to the identification of a pseudo-natural prenylated teMP inhibiting the target enzyme with an IC50 of 30 nM. Importantly, the prenylation was essential for the inhibitory activity, enhanced serum stability, and cellular uptake of the peptide, highlighting the benefits of peptide prenylation. This work showcases the de novo discovery platform for pseudo-natural prenylated peptides, which is readily applicable to other drug targets.
PubMed: 38837490
DOI: 10.1002/anie.202409973 -
Faraday Discussions Jun 2024The prenylated-flavin mononucleotide-dependent decarboxylases (also known as UbiD-like enzymes) are the most recently discovered family of decarboxylases. The modified...
The prenylated-flavin mononucleotide-dependent decarboxylases (also known as UbiD-like enzymes) are the most recently discovered family of decarboxylases. The modified flavin facilitates the decarboxylation of unsaturated carboxylic acids through a novel mechanism involving 1,3-dipolar cyclo-addition chemistry. UbiD-like enzymes have attracted considerable interest for biocatalysis applications due to their ability to catalyse (de)carboxylation reactions on a broad range of aromatic substrates at otherwise unreactive carbon centres. There are now ∼35 000 protein sequences annotated as hypothetical UbiD-like enzymes. Sequence similarity network analyses of the UbiD protein family suggests that there are likely dozens of distinct decarboxylase enzymes represented within this family. Furthermore, many of the enzymes so far characterized can decarboxylate a broad range of substrates. Here we describe a strategy to identify potential substrates of UbiD-like enzymes based on detecting enzyme-catalysed solvent deuterium exchange into potential substrates. Using ferulic acid decarboxylase (FDC) as a model system, we tested a diverse range of aromatic and heterocyclic molecules for their ability to undergo enzyme-catalysed H/D exchange in deuterated buffer. We found that FDC catalyses H/D exchange, albeit at generally very low levels, into a wide range of small, aromatic molecules that have little resemblance to its physiological substrate. In contrast, the sub-set of aromatic carboxylic acids that are substrates for FDC-catalysed decarboxylation is much smaller. We discuss the implications of these findings for screening uncharacterized UbiD-like enzymes for novel (de)carboxylase activity.
PubMed: 38837123
DOI: 10.1039/d4fd00006d -
Molecular Metabolism Jul 2024Cancer cells must maintain lipid supplies for their proliferation and do so by upregulating lipogenic gene programs. The sterol regulatory element-binding proteins...
OBJECTIVE
Cancer cells must maintain lipid supplies for their proliferation and do so by upregulating lipogenic gene programs. The sterol regulatory element-binding proteins (SREBPs) act as modulators of lipid homeostasis by acting as transcriptional activators of genes required for fatty acid and cholesterol synthesis and uptake. SREBPs have been recognized as chemotherapeutic targets in multiple cancers, however it is not well understood which SREBP target genes are essential for tumorigenesis. In this study, we examined the requirement of SREBP target genes for pancreatic ductal adenocarcinoma (PDAC) tumor growth.
METHODS
Here we constructed a custom CRISPR knockout library containing known SREBP target genes and performed in vitro 2D culture and in vivo orthotopic xenograft CRISPR screens using a patient-derived PDAC cell line. In vitro, we grew cells in medium supplemented with 10% fetal bovine serum (FBS) or 10% lipoprotein-deficient serum (LPDS) to examine differences in gene essentiality in different lipid environments. In vivo, we injected cells into the pancreata of nude mice and collected tumors after 4 weeks.
RESULTS
We identified terpenoid backbone biosynthesis genes as essential for PDAC tumor development. Specifically, we identified the non-sterol isoprenoid product of the mevalonate pathway, geranylgeranyl diphosphate (GGPP), as an essential lipid for tumor growth. Mechanistically, we observed that restricting mevalonate pathway activity using statins and SREBP inhibitors synergistically induced apoptosis and caused disruptions in small G protein prenylation that have pleiotropic effects on cellular signaling pathways. Finally, we demonstrated that geranylgeranyl diphosphate synthase 1 (GGPS1) knockdown significantly reduces tumor burden in an orthotopic xenograft mouse model.
CONCLUSIONS
These findings indicate that PDAC tumors selectively require GGPP over other lipids such as cholesterol and fatty acids and that this is a targetable vulnerability of pancreatic cancer cells.
Topics: Humans; Animals; Pancreatic Neoplasms; Mice; Mice, Nude; Cell Line, Tumor; Cell Proliferation; Polyisoprenyl Phosphates; Carcinoma, Pancreatic Ductal; Sterol Regulatory Element Binding Proteins; Clustered Regularly Interspaced Short Palindromic Repeats
PubMed: 38823776
DOI: 10.1016/j.molmet.2024.101964 -
Anticancer Research Jun 2024Thymic carcinoma is a rare cancer type with limited treatment options. Our previous study demonstrated that statins, which inhibit 3-hydroxy-3-methylglutaryl coenzyme A...
BACKGROUND/AIM
Thymic carcinoma is a rare cancer type with limited treatment options. Our previous study demonstrated that statins, which inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase, can prevent thymic carcinoma. However, the mechanisms through which statins affect intracellular events in cancer cells are not well understood. The aim of the study was to determine how thymic carcinoma modulates the intracellular signals in response to statin administration.
MATERIALS AND METHODS
We analyzed statin-induced protein phosphorylation in Ty82 human thymic carcinoma cells, which were cultured with fluvastatin, and protein phosphorylation was examined using western blotting.
RESULTS
Treating Ty82 with fluvastatin led to ERK5 phosphorylation via protein prenylation attenuation. The antitumor effects of fluvastatin on thymic carcinoma were enhanced when combined with an ERK5 inhibitor.
CONCLUSION
Statin therapy in combination with ERK5 inhibition may be a promising therapeutic approach for treating thymic carcinoma.
Topics: Fluvastatin; Humans; Thymus Neoplasms; Cell Line, Tumor; Mitogen-Activated Protein Kinase 7; Phosphorylation; Indoles; Fatty Acids, Monounsaturated; Thymoma; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Animals
PubMed: 38821590
DOI: 10.21873/anticanres.17057 -
Disease Models & Mechanisms May 2024Prenylated proteins are prevalent in eukaryotic biology (∼1-2% of proteins) and are associated with human disease, including cancer, premature aging and infections....
Prenylated proteins are prevalent in eukaryotic biology (∼1-2% of proteins) and are associated with human disease, including cancer, premature aging and infections. Prenylated proteins with a C-terminal CaaX sequence are targeted by CaaX-type prenyltransferases and proteases. To aid investigations of these enzymes and their targets, we developed Saccharomyces cerevisiae strains that express these human enzymes instead of their yeast counterparts. These strains were developed in part to explore human prenyltransferase specificity because of findings that yeast FTase has expanded specificity for sequences deviating from the CaaX consensus (i.e. atypical sequence and length). The humanized yeast strains displayed robust prenyltransferase activity against CaaX sequences derived from human and pathogen proteins containing typical and atypical CaaX sequences. The system also recapitulated prenylation of heterologously expressed human proteins (i.e. HRas and DNAJA2). These results reveal that substrate specificity is conserved for yeast and human farnesyltransferases but is less conserved for type I geranylgeranyltransferases. These yeast systems can be easily adapted for investigating the prenylomes of other organisms and are valuable new tools for helping define the human prenylome, which includes physiologically important proteins for which the CaaX modification status is unknown.
Topics: Humans; Saccharomyces cerevisiae; Protein Prenylation; Substrate Specificity; Amino Acid Sequence; Dimethylallyltranstransferase; Viral Proteins; Alkyl and Aryl Transferases
PubMed: 38818856
DOI: 10.1242/dmm.050516 -
The Journal of Biological Chemistry May 2024Recent research has identified the mechanistic Target of Rapamycin Complex 2 (mTORC2) as a conserved direct effector of Ras proteins. While previous studies suggested...
Recent research has identified the mechanistic Target of Rapamycin Complex 2 (mTORC2) as a conserved direct effector of Ras proteins. While previous studies suggested the involvement of the Switch I (SWI) effector domain of Ras in binding mTORC2 components, the regulation of the Ras-mTORC2 pathway is not entirely understood. In Dictyostelium, mTORC2 is selectively activated by the Ras protein RasC, and the RasC-mTORC2 pathway then mediates chemotaxis to cAMP and cellular aggregation by regulating the actin cytoskeleton and promoting cAMP signal relay. Here, we investigated the role of specific residues in RasC's SWI, C-terminal allosteric domain, and hypervariable region (HVR) related to mTORC2 activation. Interestingly, our results suggest that RasC SWI residue A31, which was previously implicated in RasC-mediated aggregation, regulates RasC's specific activation by the Aimless RasGEF. On the other hand, our investigation identified a crucial role for RasC SWI residue T36, with secondary contributions from E38 and allosteric domain residues. Finally, we found that conserved basic residues and the adjacent prenylation site in the HVR, which are crucial for RasC's membrane localization, are essential for RasC-mTORC2 pathway activation by allowing for both RasC's own cAMP-induced activation and its subsequent activation of mTORC2. Therefore, our findings revealed new determinants of RasC-mTORC2 pathway specificity in Dictyostelium, contributing to a deeper understanding of Ras signaling regulation in eukaryotic cells.
PubMed: 38815864
DOI: 10.1016/j.jbc.2024.107423 -
Organic & Biomolecular Chemistry Jun 2024The first biomimetic and concise racemic total syntheses of renifolin F and antiarone K, accomplished in 8 and 7 linear steps, respectively, are presented in this...
The first biomimetic and concise racemic total syntheses of renifolin F and antiarone K, accomplished in 8 and 7 linear steps, respectively, are presented in this article. Our synthetic approach commences with substituted aldehydes to produce prenylated aldol products followed by ene-type intramolecular cyclization affording a five-member core ring. This key step mediated by InCl·4HO is a novel procedure first utilized in prenylated systems which directly culminates mainly into tertiary alcohols.
PubMed: 38804914
DOI: 10.1039/d4ob00651h -
Acta Pharmaceutica Sinica. B May 2024Mornaphthoate E (MPE) is a prenylated naphthoic acid methyl ester isolated from the roots of a famous Chinese medicinal plant and shows remarkable cytotoxicity against...
Mornaphthoate E (MPE) is a prenylated naphthoic acid methyl ester isolated from the roots of a famous Chinese medicinal plant and shows remarkable cytotoxicity against several human tumor cell lines. In the current project, the first total synthesis of (±)-MPE was achieved in seven steps and 5.6% overall yield. Then the anti-tumor activity of MPE was first assessed for both enantiomers in two breast cancer cells, with the levoisomer exerting slightly better potency. The anti-tumor effect was further verified by applying the racemate in an orthotopic autograft mouse model. Notably, MPE exerted promising anti-metastasis activity both and and showed no obvious toxicity on mice at the therapeutic dosage. Mechanistic investigations demonstrated that MPE acted as a tubulin polymerization stabilizer and disturbed the dynamic equilibrium of microtubules regulating PI3K/Akt signaling. In conclusion, our work has provided a new chemical template for the future design and development of next-generation tubulin-targeting chemotherapies.
PubMed: 38799630
DOI: 10.1016/j.apsb.2024.02.012