Farnesyl phenolic enantiomers as natural MTH1 inhibitors from Ganoderma sinense

Role of MTH1 in oxidative stress and therapeutic targeting of cancer

Cancer cells maintain high levels of reactive oxygen species (ROS) to drive their growth, but ROS can trigger cell death through oxidative stress and DNA damage. To survive enhanced ROS levels, cancer cells activate their antioxidant defenses. One such defense is MTH1, an enzyme that prevents the incorporation of oxidized nucleotides into DNA, thus preventing DNA damage and allowing cancer to proliferate. MTH1 levels are often elevated in many cancers, and thus, inhibiting MTH1 is an attractive strategy for suppressing tumor growth and metastasis. Targeted MTH1 inhibition can induce DNA damage in cancer cells, exploiting their vulnerability to oxidative stress and selectively targeting them for destruction. Targeting MTH1 is promising for cancer treatment because normal cells have lower ROS levels and are less dependent on these pathways, making the approach both effective and specific to cancer. This review aims to investigate the potential of MTH1 as a therapeutic target, especially in cancer treatment, offering detailed insights into its structure, function, and role in disease progression. We also discussed various MTH1 inhibitors that have been developed to selectively induce oxidative damage in cancer cells, though their effectiveness varies. In addition, this review provide deeper mechanistic insights into the role of MTH1 in cancer prevention and oxidative stress management in various diseases.

Insights into Ganoderma fungi meroterpenoids opening a new era of racemic natural products in mushrooms

Ganoderma meroterpenoids (GMs) containing 688 structures to date were discovered to have multiple remarkable biological activities. 65.6% of meroterpenoids featuring stereogenic centers from Ganoderma species are racemates. Further, GMs from different Ganoderma species seem to have their own characteristics. In this review, a comprehensive summarization of GMs since 2000 is presented, including GM structures, structure corrections, biological activities, physicochemical properties, total synthesis, and proposed biosynthetic pathways. Additionally, we especially discuss the racemic nature, species-related structural distribution, and structure-activity relationship of GMs, which will provide a likely in-house database and shed light on future studies on GMs.

Targeting the nucleic acid oxidative damage repair enzyme MTH1: a promising therapeutic option

The accumulation of reactive oxygen species (ROS) plays a pivotal role in the development of various diseases, including cancer. Elevated ROS levels cause oxidative stress, resulting in detrimental effects on organisms and enabling tumors to develop adaptive responses. Targeting these enhanced oxidative stress protection mechanisms could offer therapeutic benefits with high specificity, as normal cells exhibit lower dependency on these pathways. MTH1 (mutT homolog 1), a homolog of Escherichia coli's MutT, is crucial in this context. It sanitizes the nucleotide pool, preventing incorporation of oxidized nucleotides, thus safeguarding DNA integrity. This study explores MTH1's potential as a therapeutic target, particularly in cancer treatment, providing insights into its structure, function, and role in disease progression.

CETSA and thermal proteome profiling strategies for target identification and drug discovery of natural products

BACKGROUND

Monitoring target engagement at various stages of drug development is essential for natural product (NP)-based drug discovery and development. The cellular thermal shift assay (CETSA) developed in 2013 is a novel, broadly applicable, label-free biophysical assay based on the principle of ligand-induced thermal stabilization of target proteins, which enables direct assessment of drug-target engagement in physiologically relevant contexts, including intact cells, cell lysates and tissues. This review aims to provide an overview of the work principles of CETSA and its derivative strategies and their recent progress in protein target validation, target identification and drug lead discovery of NPs.

METHODS

A literature-based survey was conducted using the Web of Science and PubMed databases. The required information was reviewed and discussed to highlight the important role of CETSA-derived strategies in NP studies.

RESULTS

After nearly ten years of upgrading and evolution, CETSA has been mainly developed into three formats: classic Western blotting (WB)-CETSA for target validation, thermal proteome profiling (TPP, also known as MS-CETSA) for unbiased proteome-wide target identification, and high-throughput (HT)-CETSA for drug hit discovery and lead optimization. Importantly, the application possibilities of a variety of TPP approaches for the target discovery of bioactive NPs are highlighted and discussed, including TPP-temperature range (TPP-TR), TPP-compound concentration range (TPP-CCR), two-dimensional TPP (2D-TPP), cell surface-TPP (CS-TPP), simplified TPP (STPP), thermal stability shift-based fluorescence difference in 2D gel electrophoresis (TS-FITGE) and precipitate supported TPP (PSTPP). In addition, the key advantages, limitations and future outlook of CETSA strategies for NP studies are discussed.

CONCLUSION

The accumulation of CETSA-based data can significantly accelerate the elucidation of the mechanism of action and drug lead discovery of NPs, and provide strong evidence for NP treatment against certain diseases. The CETSA strategy will certainly bring a great return far beyond the initial investment and open up more possibilities for future NP-based drug research and development.

Korean red ginseng water extract inhibits cadmium-induced lung injury via suppressing MAPK/ERK1/2/AP-1 pathway

Background

Few studies reported the therapeutic effect of Korean Red Ginseng (KRG) in lung inflammatory diseases. However, the anti-inflammatory role and underlying molecular in cadmium-induced lung injury have been poorly understood, directly linked to chronic lung diseases (CLDs): chronic obstructive pulmonary disease (COPD), cancer etc. Therefore, in this study we aim to investigate the therapeutic activities of water extract of KRG (KRG-WE) in mouse cadmium-induced lung injury model.

Method

The anti-inflammatory roles and underlying mechanisms of KRG-WE were evaluated in vitro under cadmium-stimulated lung epithelial cells (A549) and HEK293T cell line and in vivo in cadmium-induced lung injury mouse model using semi-quantitative polymerase chain reaction (RT-PCR), quantitative real-time PCR (qPCR), luciferase assay, immunoblotting, and FACS.

Results

KRG-WE strongly ameliorated the symptoms of CdSO₄-induced lung injury in mice according to total cell number in bronchoalveolar lavage fluid (BALF) and severity scores as well as cytokine levels. KRG-WE significantly suppressed the upregulation of inflammatory signaling comprising mitogen-activated protein kinases (MAPK) and their upstream enzymes. In in vitro study, KRG-WE suppressed expression of interleukin (IL)-6, matrix metalloproteinase (MMP)-2, and IL-8 while promoting recovery in CdSO₄-treated A549 cells. Similarly, KRG-WE reduced phosphorylation of MAPK and c-Jun/c-Fos in cadmium-exposed A549 cells.

Conclusion

KRG-WE was found to attenuate symptoms of cadmium-induced lung injury and reduce the expression of inflammatory genes by suppression of MAPK/AP-1-mediated pathway.

Ziprasidone suppresses pancreatic adenocarcinoma cell proliferation by targeting GOT1 to trigger glutamine metabolism reprogramming

Pancreatic ductal adenocarcinoma (PDAC) is a fatal malignant tumor whose effective treatment has not been found. The redox state and proliferative activity of PDAC cells are maintained by the conversion of aspartic acid in the cytoplasm into oxaloacetate though aspartate aminotransferase 1 (GOT1). Therefore, GOT1 inhibitors as a potential approach for treating PDAC have attracted more attention of researchers. Ziprasidone effectively inhibited GOT1 in a non-competitive manner. The potential cytotoxicity and anti-proliferation effects of ziprasidone against PDAC cells in vitro and in vivo were evaluated. Ziprasidone can induce glutamine metabolism disorder and redox state imbalance of PDAC cells by targeting GOT1, thereby inhibiting proliferation, preventing migration, and inducing apoptosis. Ziprasidone displayed significant in vivo antitumor efficacy in SW1990 cell-derived xenografts. What's more, knockdown of GOT1 in SW1990 reduced the anti-proliferative effects of ziprasidone. As a novel GOT1 inhibitor, ziprasidone may be a lead compound for the treatment of PDAC. KEY MESSAGES: Small molecule inhibitors targeting GOT1 may provide a therapeutic target in PDAC. Ziprasidone effectively inhibited GOT1 enzyme in a non-competitive manner. Ziprasidone repressed glutamine metabolism and inhibited the growth of tumor in vivo. Knockdown of GOT1 decreased the anti-proliferative effects of ziprasidone.

Caragana rosea Turcz Methanol Extract Inhibits Lipopolysaccharide-Induced Inflammatory Responses by Suppressing the TLR4/NF-κB/IRF3 Signaling Pathways

Caragana rosea Turcz, which belongs to the Leguminosae family, is a small shrub found in Northern and Eastern China that is known to possess anti-inflammatory properties and is used to treat fever, asthma, and cough. However, the underlying molecular mechanisms of its anti-inflammatory effects are unknown. Therefore, we used lipopolysaccharide (LPS) in RAW264.7 macrophages to investigate the molecular mechanisms that underlie the anti-inflammatory activities of a methanol extract of Caragana rosea (Cr-ME). We showed that Cr-ME reduced the production of nitric oxide (NO) and mRNA levels of iNOS, TNF-α, and IL-6 in a concentration-dependent manner. We also found that Cr-ME blocked MyD88- and TBK1-induced NF-κB and IRF3 promoter activity, suggesting that it affects multiple targets. Moreover, Cr-ME reduced the phosphorylation levels of IκBα, IKKα/β and IRF3 in a time-dependent manner and regulated the upstream NF-κB proteins Syk and Src, and the IRF3 protein TBK1. Upon overexpression of Src and TBK1, Cr-ME stimulation attenuated the phosphorylation of the NF-κB subunits p50 and p65 and IRF3 signaling. Together, our results suggest that the anti-inflammatory activity of Cr-ME occurs by inhibiting the NF-κB and IRF3 signaling pathways.

The chemistry and biology of fungal meroterpenoids (2009-2019)

Fungal meroterpenoids are secondary metabolites from mixed terpene-biosynthetic origins. Their intriguing chemical structural diversification and complexity, potential bioactivities, and pharmacological significance make them attractive targets in natural product chemistry, organic synthesis, and biosynthesis. This review provides a systematic overview of the isolation, chemical structural features, biological activities, and fungal biodiversity of 1585 novel meroterpenoids from 79 genera terrestrial and marine-derived fungi including macrofungi, Basidiomycetes, in 441 research papers in 2009-2019. Based on the nonterpenoid starting moiety in their biosynthesis pathway, meroterpenoids were classified into four categories (polyketide-terpenoid, indole-, shikimate-, and miscellaneous-) with polyketide-terpenoids (mainly tetraketide-) and shikimate-terpenoids as the primary source. Basidiomycota produced 37.5% of meroterpenoids, mostly shikimate-terpenoids. The genera of Ganoderma, Penicillium, Aspergillus, and Stachybotrys are the four dominant producers. Moreover, about 56% of meroterpenoids display various pronounced bioactivities, including cytotoxicity, enzyme inhibition, antibacterial, anti-inflammatory, antiviral, antifungal activities. It's exciting that several meroterpenoids including antroquinonol and 4-acetyl antroquinonol B were developed into phase II clinically used drugs. We assume that the chemical diversity and therapeutic potential of these fungal meroterpenoids will provide biologists and medicinal chemists with a large promising sustainable treasure-trove for drug discovery.

Identification of novel 1,3-diaryl-1,2,4-triazole-capped histone deacetylase 6 inhibitors with potential anti-gastric cancer activity

Histone deacetylase 6 (HDAC6) has emerged as a critical regulator of many cellular pathways in tumors due to its unique structure basis and abundant substrate types. Over the past few decades, the role played by HDAC6 inhibitors as anticancer agents has sparked great interest of biochemists worldwide. However, they were less reported for gastric cancer therapy. In this paper, with the help of bioisosteric replacement, in-house library screening, and lead optimization strategies, we designed, synthesized and verified a series of 1,3-diaryl-1,2,4-triazole-capped HDAC6 inhibitors with promising anti-gastric cancer activities. Amongst, compound 9r displayed the best inhibitory activity towards HDAC6 (IC₅₀ = 30.6 nM), with 128-fold selectivity over HDAC1. Further BLI and CETSA assay proved the high affinity of 9r to HDAC6. In addition, 9r could dose-dependently upregulate the levels of acetylated α-tubulin, without significant effect on acetylated histone H3 in MGC803 cells. Besides, 9r exhibited potent antiproliferative effect on MGC803 cells, and promoted apoptosis and suppressed the metastasis without obvious toxicity, suggesting 9r would serve as a potential lead compound for the development of novel therapeutic agents of gastric cancer.

Targeting human MutT homolog 1 (MTH1) for cancer eradication: current progress and perspectives

Since accelerated metabolism produces much higher levels of reactive oxygen species (ROS) in cancer cells compared to ROS levels found in normal cells, human MutT homolog 1 (MTH1), which sanitizes oxidized nucleotide pools, was recently demonstrated to be crucial for the survival of cancer cells, but not required for the proliferation of normal cells. Therefore, dozens of MTH1 inhibitors have been developed with the aim of suppressing cancer growth by accumulating oxidative damage in cancer cells. While several inhibitors were indeed confirmed to be effective, some inhibitors failed to kill cancer cells, complicating MTH1 as a viable target for cancer eradication. In this review, we summarize the current status of developing MTH1 inhibitors as drug candidates, classify the MTH1 inhibitors based on their structures, and offer our perspectives toward the therapeutic potential against cancer through the targeting of MTH1.

Anti-inflammatory activities of Canarium subulatum Guillaumin methanol extract operate by targeting Src and Syk in the NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Canarium subulatum Guillaumin is an herbal medicinal plant native to Southeast Asia. Ethnopharmacological evidence suggests that plants of the genus Canarium cure a variety of inflammatory diseases.

AIM OF THE STUDY

The pharmacological mechanisms of C. subulatum Guillaumin remain poorly understood. In this study, we investigate inflammatory mechanisms and target molecules using C. subulatum Guillaumin methanol extract (Cs-ME) in inflammatory reactions managed by macrophages.

MATERIALS AND METHODS

To identify the anti-inflammatory activities of Cs-ME, lipopolysaccharide (LPS)-stimulated macrophages and a murine HCl/EtOH-induced gastritis model were chosen. The luciferase reporter gene assay, Western blot analysis, overexpression strategy, and the cellular thermal shift assay (CETSA) were employed to investigate the molecular mechanisms and target enzymes of Cs-ME. The active ingredients of this extract were also determined by HPLC.

RESULTS

Released levels of nitric oxide (NO) and mRNA expression levels of iNOS and IL-6 were downregulated by Cs-ME without exhibiting cytotoxicity. This extract inhibited MyD88-induced promoter activity and the nuclear translocation of nuclear factor (NF)-κB. Moreover, we found that Cs-ME reduced the phosphorylation of NF-κB upstream signaling molecules including IκBα, IKKα/β, Src, and Syk in LPS-stimulated macrophage-like RAW264.7 cells. The results of Western blot and CETSA confirmed that Src and Syk are anti-inflammatory targets of Cs-ME. In addition, orally injected Cs-ME alleviated HCl/EtOH-induced gastric ulcers in mice. HPLC analysis indicated that quercetin, luteolin, and kaempferol are major active components of this extract with anti-inflammatory activity.

CONCLUSIONS

Cs-ME exhibits anti-inflammatory effects in vitro and in vivo by targeting Src and Syk in the NF-κB signaling pathway. Consequently, Cs-ME could be developed as an anti-inflammatory herbal medicine.

Triterpenoids from Ganoderma lucidum and Their Potential Anti-inflammatory Effects

Ganoderma lucidum, as food, tea, dietary supplement, and medicine, is widely used in China and Eastern Asian countries. In order to discover its anti-inflammatory constituents and provide some references for the usage of G. lucidum and G. sinense, two official species in China, the fruiting bodies of G. lucidum were studied, leading to the isolation of six new triterpenoids (1-6) and 27 known analogues (7-33). Compound 4 exhibited the most potent inhibition on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells. The production of IL-6 and IL-1β, as well as the expression of iNOS, COX-2, and NF-κB were dose-dependently reduced by 4. The phosphorylations of IκBα and IKKβ in LPS-induced macrophage cells were blocked by 4. Therefore, 4 could be used as a potential anti-inflammatory candidate and the total triterpenoids might be developed as value-added functional food for the prevention of inflammation. In combination of previous studies, it should be cautious for the interchangeable usage of G. lucidum and G. sinense.

Azacoccone E inhibits cancer cell growth by targeting 3-phosphoglycerate dehydrogenase

Serine plays critically important roles in tumorigenesis. Homo sapiens 3-phosphoglycerate dehydrogenase (PHGDH) catalyzes the first committed step for the synthesis of glucose-derived serine via the phosphoserine pathway and has been associated with a wide variety of cancers, including breast cancer, melanoma, colon cancer, glioma, nasopharyngeal carcinoma, cervical adenocarcinoma, etc. Azacoccone E, an aza-epicoccone derivative from the culture of Aspergillus flavipes, exhibited effective inhibitory activity against PHGDH in vitro. The microscale thermophoresis (MST) method and the cellular thermal shift assay (CETSA) confirmed that azacoccone E directly bound to PHGDH. And the cell-based experiments showed that this compound was selectively toxic to PHGDH-dependent cancer cells and could cause apoptosis. Further biochemical assays revealed that it was a noncompetitive inhibitor with respect to the substrate of 3-PG and exhibited a time-dependent inhibition. Furthermore, molecular docking demonstrated that azacoccone E coordinated in an allosteric site of PHGDH with low binding energy. Therefore, azacoccone E can be considered as a possible drug candidate targeting at PHGDH for treatment of cancers.

Ixocarpalactone A from dietary tomatillo inhibits pancreatic cancer growth by targeting PHGDH

3-Phosphoglycerate dehydrogenase (PHGDH) has been reported to associate with tumorigenesis in many cancers. IoxA, a natural withanolide obtained from dietary tomatillo (Physalis ixocarpa), was identified as the novel natural PHGDH inhibitor with high targeting and low toxicities for treatment of pancreatic cancers.

The dietary compound luteolin inhibits pancreatic cancer growth by targeting BCL-2

Luteolin, a bioactive flavonoid from celery (Apium graveolens), has been rationally proved to trigger SW1990 cells to apoptosis by targeting BCL-2, and may serve as a potential agent for this cancer therapy.