Mycosynthetix (United States)

Perylenequinones (PQs) such as hypocrellins and hypomycinsarefungal-derived redox-active metabolites with known roles as photosensitizersin the oxidative stress response and applications in photodynamictherapy (PDT). Here, we report that Shiraia sp.,a filamentous fungus, can survive and grow under strictly anaerobic(argon) conditionsan unexpected finding for a multicellulareukaryote. Modulating redox homeostasis through chemical reductionand oxygen limitation promotes the intramolecular cyclization of hypocrellins,enhancing hypomycin biosynthesis. Moisture content further influencesthese transformations, with high water levels favoring keto–enoltautomerization and dry, reducing environments promoting hydride substitutionat the peripheral positions. These findings highlight redox modulationas a key driver of perylenequinone metabolism and suggest that PQsmay contribute to maintaining redox balance under anaerobic stress,hinting at a broader role in oxygen-independent adaptation in filamentousfungi. This work offers new insights at the interface of redox biology,chemical signaling, and fungal metabolism, with potential implicationsfor the stability and function of PQ-based PDT agents in hypoxic,reducing conditions such as tumor microenvironments.

Multiple myeloma (MM) is a hematologic malignancy associated with malignant plasma cell proliferation in the bone marrow. Despite the available treatments, drug resistance and adverse side effects pose significant challenges, underscoring the need for alternative therapeutic strategies. Natural products, like the fungal metabolite neosetophomone B (NSP-B), have emerged as potential therapeutic agents due to their bioactive properties. Our study investigated NSP-B's antitumor effects on MM cell lines (U266 and RPMI8226) and the involved molecular mechanisms. NSP-B demonstrated significant growth inhibition and apoptotic induction, triggered by reduced AKT activation and downregulation of the inhibitors of apoptotic proteins and S-phase kinase protein. This was accompanied by an upregulation of p21Kip1 and p27Cip1 and an elevated Bax/BCL2 ratio, culminating in caspase-dependent apoptosis. Interestingly, NSP-B also enhanced the cytotoxicity of bortezomib (BTZ), an existing MM treatment. Overall, our findings demonstrated that NSP-B induces caspase-dependent apoptosis, increases cell damage, and suppresses MM cell proliferation while improving the cytotoxic impact of BTZ. These findings suggest that NSP-B can be used alone or in combination with other medicines to treat MM, highlighting its importance as a promising phytoconstituent in cancer therapy.

Verticillins are epipolythiodioxopiperazine alkaloids isolated from a fungus with nanomolar anti-tumor activity in high-grade serous ovarian cancer (HGSOC). HGSOC is the fifth leading cause of death in women, and natural products continue to be an inspiration for new drug entities to help tackle chemoresistance. Verticillin D was recently found in a new fungal strain and compared to verticillin A. Both compounds exhibited nanomolar cytotoxic activity against OVCAR4 and OVCAR8 HGSOC cell lines, significantly reduced 2D foci and 3D spheroids, and induced apoptosis. In addition, verticillin A and verticillin D reduced tumor burden in vivo using OVCAR8 xenografts in the peritoneal space as a model. Unfortunately, mice treated with verticillin D displayed signs of liver toxicity. Tolerability studies to optimize verticillin A formulation for in vivo delivery were performed and compared to a semi-synthetic succinate version of verticillin A to monitor bioavailability in athymic nude females. Formulation of verticillins achieved tolerable drug delivery. Thus, formulation studies are effective at improving tolerability and demonstrating efficacy for verticillins.

Hypocrellins and hypomycins are two sub-classes of fungalperylenequinones with unique structural, biological, and photochemicalproperties. With the growing interest in these naturally-occurringphotosensitizers, more studies were warranted to better understand thestructural relationships between these two sub-classes of perylenequinones. Inthis study, the long-postulated biosynthetic precursor (7) of classB fungal perylenequinones was isolated and characterized from aShiraia-like sp. (strain MSX60519). Furthermore, theelectrochemical and chemical redox behaviors of hypocrellins and hypomycins wereinvestigated under aerobic and anaerobic conditions. These studies served todefine the structural relationship within hypocrellins (1-3), whichwas further supported by X-ray crystallography, and between hypocrellins andhypomycins (4-6). Chemical reductions of hypocrellins underanaerobic conditions identified the origin of hypomycin A (4),hypomycin C (5), and hypomycin E (6), which in turnserved to confirm 4 and revise the absolute configurations of5 and 6. Hypocrellins were shown to undergoreversible reduction and re-oxidation under aerobic conditions, while in ananaerobic environment and longer timescale, the fully reduced form can, to someextent, undergo an intramolecular ring closing metathesis. This may impart ameans of reductive pathway for self-protection against these phototoxins andexplain the chemical diversity observed in the fungal metabolites.

The verticillins, a class of epipolythiodioxopiperazine alkaloids (ETPs) first described 50 years ago with the discovery of verticillin A (1), have gained attention due to their potent activity against cancer cells, noted both in vitro and in vivo. In this study, the complex scaffold afforded through optimized fermentation was used as a feedstock for semisynthetic efforts designed to explore the reactivity of the C11 and C11' hydroxy substituents. Functionality introduced at these positions would be expected to impact not only the potency but also the pharmacokinetic properties of the resulting compound. With this in mind, verticillin H (2) was used as a starting material to generate nine semisynthetic analogues (4-12) containing a variety of ester, carbonate, carbamate, and sulfonate moieties. Likewise, verticillin A succinate (13) was synthesized from 1 to demonstrate the successful application of this strategy to other ETPs. The synthesized compounds and their corresponding starting materials (i.e., 1 and 2) were screened for activity against a panel of melanoma, breast, and ovarian cancer cell lines: MDA-MB-435, MDA-MB-231, and OVCAR3. All analogues retained IC50 values in the nanomolar range, comparable to, and in some cases more potent than, the parent compounds.

A series of thielavins I, V, and Q (1-3) and the previously undescribed thielavin Z8 (4) were isolated from cultures of a fungal Shiraia-like sp. (strain MSX60519) that were grown under a suite of media and light conditions, with enhanced biosynthesis noted using rice as a substrate with 12:12 h light:dark cycles. Conversely, oatmeal medium and continuous white LED light exposure negatively affected the production of these compounds, at least by strain MSX60519. The structure of 4 was determined using NMR spectroscopic data and mass fragmentation patterns. Of note, the utility of LR-HSQMBC and NOESY NMR experiments in the structural elucidation of these hydrogen-deficient natural products was demonstrated. Compounds 1-4 exhibited cytotoxic activity at the micromolar level against human breast, ovarian, and melanoma cancer cell lines.