Fungal secondary metabolites rasfonin induces autophagy, apoptosis and necroptosis in renal cancer cell line

<p>Rasfonin (A304) is a fungal natural product isolated from the fermentation substrate of <i>Talaromyces</i> sp. 3656-A1, which was named according to its activity against the small G-protein Ras. In a former study, we demonstrated that it induced autophagy and apoptosis; however, whether rasfonin activated necroptosis remained unknown. Moreover, the interplay among different cell death processes induced by rasfonin was unexplored. In the present study, we revealed that, in addition of promoting autophagy and caspase-dependent apoptosis, rasfonin also activated necroptosis. Nectrostatin-1 (Nec-1), an inhibitor of necroptosis, affected rasfonin-induced autophagy in a time-dependent manner concurring with an increased caspase-dependent apoptosis. The aforementioned results were confirmed by knockdown of receptor-interacting protein 1 (RIP1), a crucial necrostatin-1-targeted adaptor kinase mediating cell death and survival. Taken together, the data presented indicate that rasfonin activates various cell death pathways, and RIP1 plays a critical role in rasfonin-induced autophagy and apoptosis.</p

Dioxatricyclic and Oxabicyclic Polyketides from <i>Trichocladium opacum</i>

Five new polyketides, trichocladinols D–H (<b>1</b>–<b>5</b>) with dioxatricyclic (<b>1</b>–<b>3</b>) and oxabicyclic (<b>4</b> and <b>5</b>) skeletons, and the known massarilactone C (<b>6</b>) were isolated from the solid-substrate fermentation cultures of the ascomycete fungus <i>Trichocladium opacum</i>. The structures of <b>1</b>–<b>5</b> were determined mainly by NMR experiments, and <b>1</b>, <b>3</b>, and <b>4</b> were confirmed by X-ray crystallography. The absolute configurations of <b>1</b> and <b>3</b> were assigned by X-ray crystallography using Cu Kα radiation, whereas that of C-5 in <b>2</b> and <b>4</b> was deduced via the circular dichroism (CD) data. Compounds <b>2</b>–<b>4</b> showed weak cytotoxicity against the human tumor cell lines A549, HCT116, and SW480

Festuca loliacea

Three new <i>ent</i>-eudesmane sesquiterpenoids, arundinols A–C (<b>1</b>–<b>3</b>), one isochroman-1-one, arundinone A (<b>4</b>), and a polyoxygenated benzofuran-3­(2<i>H</i>)-one dimer, arundinone B (<b>5</b>), were isolated from the extract of a plant endophytic fungus, <i>Microsphaeropsis arundinis</i>. Their structures were elucidated primarily by NMR experiments, and <b>1</b> was confirmed by X-ray crystallography. The absolute configuration of <b>1</b> was assigned by X-ray crystallography using Cu Kα radiation, whereas those of the C-11 tertiary alcohols in <b>2</b> and <b>3</b> were deduced via the circular dichroism data of the in situ formed [Rh₂(OCOCF₃)₄] complexes. Arundinone B (<b>5</b>) represents the first dimeric benzofuran-3­(2<i>H</i>)-one, showing cytotoxicity against T24 and A549 cells. The co-isolated known compound <b>6</b> showed a modest inhibitory effect against <i>Staphylococcus aureus</i>

Cytotoxic Cleistanthane and Cassane Diterpenoids from the Entomogenous Fungus <i>Paraconiothyrium hawaiiense</i>

Hawaiinolides A–D (<b>1</b>–<b>4</b>), four new secondary metabolites including three cleistanthane (<b>1</b>, <b>3</b>, and <b>4</b>) and one cassane (<b>2</b>) type of diterpene lactones, were isolated from the crude extract of <i>Paraconiothyrium hawaiiense</i>, a fungus entomogenous to the <i>Septobasidium</i>-infected insect <i>Diaspidiotus</i> sp. The structures of <b>1</b>–<b>4</b> were elucidated by nuclear magnetic resonance experiments, and <b>1</b> and <b>3</b> were further confirmed by X-ray crystallography. The absolute configuration of <b>1</b> was assigned via single-crystal X-ray diffraction analysis using Cu Kα radiation, whereas that of <b>2</b>–<b>4</b> was deduced via the circular dichroism data. Compound <b>1</b> showed significant cytotoxicity against a small panel of five human tumor cell lines, A549, T24, HeLa, HCT116, and MCF-7

Cytotoxic Cleistanthane and Cassane Diterpenoids from the Entomogenous Fungus <i>Paraconiothyrium hawaiiense</i>

Hawaiinolides A–D (<b>1</b>–<b>4</b>), four new secondary metabolites including three cleistanthane (<b>1</b>, <b>3</b>, and <b>4</b>) and one cassane (<b>2</b>) type of diterpene lactones, were isolated from the crude extract of <i>Paraconiothyrium hawaiiense</i>, a fungus entomogenous to the <i>Septobasidium</i>-infected insect <i>Diaspidiotus</i> sp. The structures of <b>1</b>–<b>4</b> were elucidated by nuclear magnetic resonance experiments, and <b>1</b> and <b>3</b> were further confirmed by X-ray crystallography. The absolute configuration of <b>1</b> was assigned via single-crystal X-ray diffraction analysis using Cu Kα radiation, whereas that of <b>2</b>–<b>4</b> was deduced via the circular dichroism data. Compound <b>1</b> showed significant cytotoxicity against a small panel of five human tumor cell lines, A549, T24, HeLa, HCT116, and MCF-7

A Botryane Metabolite with a New Hexacyclic Skeleton from an Entomogenous Fungus <i>Hypocrea</i> sp.

Hypocrolide A (<b>1</b>), a botryane metabolite with a new hexacyclic skeleton, was isolated from cultures of the entomogenous fungus <i>Hypocrea</i> sp. The proposed structure was confirmed by X-ray crystallography using Cu Kα radiation. The mixed-biogenetic skeleton could be derived from the hypothetical precursors related to coumarin and dihydrobotrydiol, and the latter may be derived from the coisolated 10-oxodehydrodihydrobotrydial (<b>2</b>) or a similar analogue

Data_Sheet_1_Heterologous Biosynthesis of the Fungal Sesquiterpene Trichodermol in Saccharomyces cerevisiae.XLS

<p>Trichodermol, a fungal sesquiterpene derived from the farnesyl diphosphate pathway, is the biosynthetic precursor for trichodermin, a member of the trichothecene class of fungal toxins produced mainly by the genera of Trichoderma and Fusarium. Trichodermin is a promising candidate for the development of fungicides and antitumor agents due to its significant antifungal and cytotoxic effects. It can also serve as a scaffold to generate new congeners for structure-activity relationship (SAR) study. We reconstructed the biosynthetic pathway of trichodermol in Saccharomyces cerevisiae BY4741, and investigated the effect of produced trichodermol on the host by de novo RNA sequencing (RNA-Seq) and quantitative Real-time PCR analyses. Co-expression of pESC::FgTRI5 using plasmid pLLeu-tHMGR-UPC2.1 led to trichodiene production of 683 μg L^-1, while integration of only the codon-optimized FgTRI5 into the chromosome of yeast improved the production to 6,535 μg L^-1. Subsequent expression of the codon-optimized cytochrome P450 monooxygenase encoding genes, TaTRI4 and TaTRI11, resulted in trichodermol, with an estimated titer of 252 μg L^-1 at shake flask level. RNA-Seq and qPCR analyses revealed that the produced trichodermol downregulated the expression of the genes involved in ergosterol biosynthesis, but significantly upregulated the expression of PDR5 related to membrane transport pathway in S. cerevisiae. Collectively, we achieved the first heterologous biosynthesis of trichodermol by reconstructing its biosynthetic pathway in yeast, and the reconstructed pathway will serve as a platform to generate trichodermin analogs as potential candidates for agrochemicals and anticancer agents through further optimizations.</p

Identification of Oxaphenalenone Ketals from the Ascomycete Fungus <i>Neonectria</i> sp.

Neonectrolides B–E (<b>4</b>–<b>7</b>), four new oxaphenalenone ketals incorporating the new furo­[2,3-<i>b</i>]­isochromeno­[3,4,5-<i>def</i>]­chromen-11­(6a<i>H</i>)-one skeleton, were isolated from the fermentation extract of the ascomycete fungus <i>Neonectria</i> sp. in an in-depth investigation guided by HPLC fingerprint and a cytotoxicity assay. The previously identified oxaphenalenone spiroketal neonectrolide A (<b>1</b>) and its putative biosynthetic precursors (<b>2</b> and <b>3</b>) were also reisolated in the current work. The structures of <b>4</b>–<b>7</b> were primarily elucidated by interpretation of NMR spectroscopic data, and the absolute configurations were deduced by electronic circular dichroism calculations. Compound <b>6</b> showed cytotoxic effects against four of the six human tumor cell lines tested. Biosynthetically, compounds <b>4</b>–<b>7</b> could be derived via the Diels–Alder reaction cascades starting from derivatives of the co-isolated metabolites <b>2</b> and <b>3</b>

A Botryane Metabolite with a New Hexacyclic Skeleton from an Entomogenous Fungus <i>Hypocrea</i> sp.

Hypocrolide A (<b>1</b>), a botryane metabolite with a new hexacyclic skeleton, was isolated from cultures of the entomogenous fungus <i>Hypocrea</i> sp. The proposed structure was confirmed by X-ray crystallography using Cu Kα radiation. The mixed-biogenetic skeleton could be derived from the hypothetical precursors related to coumarin and dihydrobotrydiol, and the latter may be derived from the coisolated 10-oxodehydrodihydrobotrydial (<b>2</b>) or a similar analogue

Data_Sheet_2_Heterologous Biosynthesis of the Fungal Sesquiterpene Trichodermol in Saccharomyces cerevisiae.XLS

<p>Trichodermol, a fungal sesquiterpene derived from the farnesyl diphosphate pathway, is the biosynthetic precursor for trichodermin, a member of the trichothecene class of fungal toxins produced mainly by the genera of Trichoderma and Fusarium. Trichodermin is a promising candidate for the development of fungicides and antitumor agents due to its significant antifungal and cytotoxic effects. It can also serve as a scaffold to generate new congeners for structure-activity relationship (SAR) study. We reconstructed the biosynthetic pathway of trichodermol in Saccharomyces cerevisiae BY4741, and investigated the effect of produced trichodermol on the host by de novo RNA sequencing (RNA-Seq) and quantitative Real-time PCR analyses. Co-expression of pESC::FgTRI5 using plasmid pLLeu-tHMGR-UPC2.1 led to trichodiene production of 683 μg L^-1, while integration of only the codon-optimized FgTRI5 into the chromosome of yeast improved the production to 6,535 μg L^-1. Subsequent expression of the codon-optimized cytochrome P450 monooxygenase encoding genes, TaTRI4 and TaTRI11, resulted in trichodermol, with an estimated titer of 252 μg L^-1 at shake flask level. RNA-Seq and qPCR analyses revealed that the produced trichodermol downregulated the expression of the genes involved in ergosterol biosynthesis, but significantly upregulated the expression of PDR5 related to membrane transport pathway in S. cerevisiae. Collectively, we achieved the first heterologous biosynthesis of trichodermol by reconstructing its biosynthetic pathway in yeast, and the reconstructed pathway will serve as a platform to generate trichodermin analogs as potential candidates for agrochemicals and anticancer agents through further optimizations.</p