Triterpene Acids from Frankincense and Semi-Synthetic Derivatives That Inhibit 5-Lipoxygenase and Cathepsin G

Age-related diseases, such as osteoarthritis, Alzheimer’s disease, diabetes, and cardiovascular disease, are often associated with chronic unresolved inflammation. Neutrophils play central roles in this process by releasing tissue-degenerative proteases, such as cathepsin G, as well as pro-inflammatory leukotrienes produced by the 5-lipoxygenase (5-LO) pathway. Boswellic acids (BAs) are pentacyclic triterpene acids contained in the gum resin of the anti-inflammatory remedy frankincense that target cathepsin G and 5-LO in neutrophils, and might thus represent suitable leads for intervention with age-associated diseases that have a chronic inflammatory component. Here, we investigated whether, in addition to BAs, other triterpene acids from frankincense interfere with 5-LO and cathepsin G. We provide a comprehensive analysis of 17 natural tetra- or pentacyclic triterpene acids for suppression of 5-LO product synthesis in human neutrophils. These triterpene acids were also investigated for their direct interference with 5-LO and cathepsin G in cell-free assays. Furthermore, our studies were expanded to 10 semi-synthetic BA derivatives. Our data reveal that besides BAs, several tetra- and pentacyclic triterpene acids are effective or even superior inhibitors of 5-LO product formation in human neutrophils, and in parallel, inhibit cathepsin G. Their beneficial target profile may qualify triterpene acids as anti-inflammatory natural products and pharmacological leads for intervention with diseases related to aging

Synthesis and structure-activity-relationships of boswellic acids and derivatives

Extrakte und Verreibungen des Weihrauchharzes Olibanum von Boswellia serrata werden wegen ihrer antiinflammatorischen Wirkung seit Jahrtausenden in der indischen Volksmedizin Ayurveda eingesetzt. Als wirksame Bestandteile wurden so genannte beta-Boswelliasäuren identifiziert, die zur Substanzklasse der pentazyklischen Triterpene gehören und bis dato als spezifische Inhibitoren der 5-Lipoxygenase betrachtet werden. Die Anbindung von beta-Boswelliasäuren an EAH Sepharose 4B® ermöglichte durch die Identifikation dreier neuer Targets einen Beitrag zur Aufklärung des Wirkungsmechanismus dieser Substanzen, weshalb beta-Boswelliasäuren nicht länger als spezifische Inhibitoren der 5-Lipoxygenase zu betrachten sind. Die Synthese zahlreicher Derivate ermöglichte die Durchführung von Aktivitätsmessungen an neuen und bekannten Targets zur Aufstellung von Struktur-Wirkungs-Beziehungen. Motivation für die Synthesen waren gezielte Molecular Modeling Berechnungen sowie der Wunsch, das hydrophobe Grundgerüst hydrophiler zu machen und bereits bestehende Synthesemethoden zu verbessern. Durch die Umsetzung von beta-Boswelliasäuren mit Gallussäure gelang die Darstellung eines potenten 5-Lipoxygenase-Inhibitors, dessen Wirkung auf einer dualen Hemmung des Enzyms beruht. Die Targetfishing-Experimente sowie die Aktivitätsmessungen wurden in Kooperation mit der Arbeitsgruppe WERZ (Universität Tübingen) durchgeführt.Extracts and preparations of frankincense from Boswellia serrata are used in Indian folk medicine Ayurveda due to their anti-inflammatory activity for thousands of years. The so called beta-boswellic acids which belong to the class of pentacyclic triterpenes were identified as effective components and are so far regarded as specific inhibitors of 5-lipoxygenase. The immobilization of beta-boswellic acids at EAH Sepharose 4B™ enabled the identification of three new targets of these compounds, giving new insights into the mode of action of beta-boswellic acids. Therefore they should no longer be regarded as specific inhibitors of 5-lipoxygenase. Motivated by selective molecular modeling calculations as well as the wish to make the hydrophobic basis more hydrophilic and to improve already existing synthetic methods, numerous derivatives of beta-boswellic acids were synthesized. Their activities were tested with different targets to establish structure-activity-relationships. The reaction of beta-boswellic acids with gallic acid led to a potent 5-lipoxygenase inhibitor which inhibits the enzyme by two different mechanisms. Targetfishing experiments as well as the activity tests were carried out in cooperation with the group of Prof. Dr. WERZ (University Tübingen)

Triterpene acids from frankincense and semi-synthetic derivatives that inhibit 5-Lipoxygenase and Cathepsin G

Age-related diseases, such as osteoarthritis, Alzheimer’s disease, diabetes, and cardiovascular disease, are often associated with chronic unresolved inflammation. Neutrophils play central roles in this process by releasing tissue-degenerative proteases, such as cathepsin G, as well as pro-inflammatory leukotrienes produced by the 5-lipoxygenase (5-LO) pathway. Boswellic acids (BAs) are pentacyclic triterpene acids contained in the gum resin of the anti-inflammatory remedy frankincense that target cathepsin G and 5-LO in neutrophils, and might thus represent suitable leads for intervention with age-associated diseases that have a chronic inflammatory component. Here, we investigated whether, in addition to BAs, other triterpene acids from frankincense interfere with 5-LO and cathepsin G. We provide a comprehensive analysis of 17 natural tetra- or pentacyclic triterpene acids for suppression of 5-LO product synthesis in human neutrophils. These triterpene acids were also investigated for their direct interference with 5-LO and cathepsin G in cell-free assays. Furthermore, our studies were expanded to 10 semi-synthetic BA derivatives. Our data reveal that besides BAs, several tetra- and pentacyclic triterpene acids are effective or even superior inhibitors of 5-LO product formation in human neutrophils, and in parallel, inhibit cathepsin G. Their beneficial target profile may qualify triterpene acids as anti-inflammatory natural products and pharmacological leads for intervention with diseases related to aging

Triterpene Acids from Frankincense and Semi-Synthetic Derivatives That Inhibit 5-Lipoxygenase and Cathepsin G

Age-related diseases, such as osteoarthritis, Alzheimer’s disease, diabetes, and cardiovascular disease, are often associated with chronic unresolved inflammation. Neutrophils play central roles in this process by releasing tissue-degenerative proteases, such as cathepsin G, as well as pro-inflammatory leukotrienes produced by the 5-lipoxygenase (5-LO) pathway. Boswellic acids (BAs) are pentacyclic triterpene acids contained in the gum resin of the anti-inflammatory remedy frankincense that target cathepsin G and 5-LO in neutrophils, and might thus represent suitable leads for intervention with age-associated diseases that have a chronic inflammatory component. Here, we investigated whether, in addition to BAs, other triterpene acids from frankincense interfere with 5-LO and cathepsin G. We provide a comprehensive analysis of 17 natural tetra- or pentacyclic triterpene acids for suppression of 5-LO product synthesis in human neutrophils. These triterpene acids were also investigated for their direct interference with 5-LO and cathepsin G in cell-free assays. Furthermore, our studies were expanded to 10 semi-synthetic BA derivatives. Our data reveal that besides BAs, several tetra- and pentacyclic triterpene acids are effective or even superior inhibitors of 5-LO product formation in human neutrophils, and in parallel, inhibit cathepsin G. Their beneficial target profile may qualify triterpene acids as anti-inflammatory natural products and pharmacological leads for intervention with diseases related to aging

Nerve Fibers in the Tumor Microenvironment Are Co-Localized with Lymphoid Aggregates in Pancreatic Cancer

B cells and tertiary lymphoid structures (TLS) are reported to be important in survival in cancer. Pancreatic Cancer (PDAC) is one of the most lethal cancer types, and currently, it is the seventh leading cause of cancer-related death worldwide. A better understanding of tumor biology is pivotal to improve clinical outcome. The desmoplastic stroma is a complex system in which crosstalk takes place between cancer-associated fibroblasts, immune cells and cancer cells. Indirect and direct cellular interactions within the tumor microenvironment (TME) drive key processes such as tumor progression, metastasis formation and treatment resistance. In order to understand the aggressiveness of PDAC and its resistance to therapeutics, the TME needs to be further unraveled. There are some limited data about the influence of nerve fibers on cancer progression. Here we show that small nerve fibers are located at lymphoid aggregates in PDAC. This unravels future pathways and has potential to improve clinical outcome by a rational development of new therapeutic strategies

Nerve Fibers in the Tumor Microenvironment Are Co-Localized with Lymphoid Aggregates in Pancreatic Cancer

B cells and tertiary lymphoid structures (TLS) are reported to be important in survival in cancer. Pancreatic Cancer (PDAC) is one of the most lethal cancer types, and currently, it is the seventh leading cause of cancer-related death worldwide. A better understanding of tumor biology is pivotal to improve clinical outcome. The desmoplastic stroma is a complex system in which crosstalk takes place between cancer-associated fibroblasts, immune cells and cancer cells. Indirect and direct cellular interactions within the tumor microenvironment (TME) drive key processes such as tumor progression, metastasis formation and treatment resistance. In order to understand the aggressiveness of PDAC and its resistance to therapeutics, the TME needs to be further unraveled. There are some limited data about the influence of nerve fibers on cancer progression. Here we show that small nerve fibers are located at lymphoid aggregates in PDAC. This unravels future pathways and has potential to improve clinical outcome by a rational development of new therapeutic strategies

Author Correction:Pan-cancer image-based detection of clinically actionable genetic alterations (Nature Cancer, (2020), 1, 8, (789-799), 10.1038/s43018-020-0087-6)

In the version of this article initially published, the sample size (n = 794) was incorrect in Fig. 2f and Extended Data Fig. 4a,e; the correct sample size is ‘n = 397’. The sample size (n = 826) was also incorrect in Fig. 2h and Extended Data Fig. 4q,u; the correct sample size is ‘n = 413’. Also, the values in Supplementary Table 2, row ‘TCGA-HNSC’, column ‘Quality OK and tumor on slide’ (424, 424) were incorrect;the correct values are ‘457, 439’. The errors have been corrected in the HTML and PDF versions of the article