8-Epi-xanthatin induces the apoptosis of DU145 prostate carcinoma cells through signal transducer and activator of transcription 3 inhibition and reactive oxygen species generation

Acovenosigenin A β-glucoside mediates JAK2-STAT3 signaling pathway by targeting GP130 in A549 and H460 cells based on integrative analysis of transcriptome and proteome and biological verification

Acovenosigenin A β-glucoside (AAG) is a cardiac glycoside derived from Streptocaulon juventas (Lour.) Merr, which exhibited the potential in treating lung cancer in our previous research. However, the action mechanism remains unclear. In this research, JAK2-STAT3 signaling pathway was predicted to be the critical regulation pathway based on the integrative analysis of transcriptome and proteome. Western blotting and qPCR assays were performed to identify that AAG can regulate JAK2-STAT3 signaling pathway and its downstream genes, such as c-Myc, Survivin, Cyclin B1, CDK1, Bcl-2. And this action of AAG depended on the suppression of STAT3 phosphorylation and its nuclear translocation through the experiments of Immunofluorescence, transient transfection and cryptotanshinone treatment. Additionally, AAG was discovered to mediate the JAK2-STAT3 pathway in IL-6-driven A549 and H460 cells, which in turn inhibited cell proliferation, promoted mitochondria-related apoptosis, and arrested the cell cycle progression. By molecular docking analysis, CETSA and SIP experiments, the protein of GP130 was identified as the specific target of AAG in A549 and H460 cells. Further studies suggested that AAG inhibited JAK2-STAT3 pathway and its downstream genes by targeting GP130 in nude mice xenograft model in vivo. This research presented that AAG exhibits the promising potential in the treatment of NSCLC.

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.

Telocinobufagin inhibits osteosarcoma growth and metastasis by inhibiting the JAK2/STAT3 signaling pathway

Osteosarcoma is the most common primary bone malignancy in children and adolescents; it exhibits rapid growth and a high metastatic potential and may thus lead to relatively high mortality. The JAK2/STAT3 signaling pathway, which plays a critical role in the occurrence and development of osteosarcoma, is a potential target for the treatment of osteosarcoma. Here, we identified the natural product telocinobufagin (TCB), which is a component isolated from toad cake, as a potent candidate with anti-osteosarcoma effects. TCB inhibited osteosarcoma cell growth, migration, invasion and induced cancer cell apoptosis. Mechanistically, TCB specifically inhibited the JAK2/STAT3 signaling pathway. More importantly, TCB significantly suppressed tumor growth and metastasis in an osteosarcoma xenograft animal model. Moreover, TCB also showed strong inhibitory effects in other cancer types, such as lung cancer, liver cancer, colon cancer, breast cancer and gastric cancer. Hence, our study reveals TCB as a potent anti-osteosarcoma therapeutic agent that inhibits the JAK2/STAT3 signaling pathway.

Targeting regulated cell death with plant natural compounds for cancer therapy: A revisited review of apoptosis, autophagy-dependent cell death, and necroptosis

Regulated cell death (RCD) refers to programmed cell death regulated by various protein molecules, such as apoptosis, autophagy-dependent cell death, and necroptosis. Accumulating evidence has recently revealed that RCD subroutines have several links to many types of human cancer; therefore, targeting RCD with pharmacological small-molecule compounds would be a promising therapeutic strategy. Moreover, plant natural compounds, small-molecule compounds synthesized from plant sources, and their derivatives have been widely reported to regulate different RCD subroutines to improve potential cancer therapy. Thus, in this review, we focus on updating the intricate mechanisms of apoptosis, autophagy-dependent cell death, and necroptosis in cancer. Moreover, we further discuss several representative plant natural compounds and their derivatives that regulate the above-mentioned three subroutines of RCD, and their potential as candidate small-molecule drugs for the future cancer treatment.

Differentiated embryonic chondrocyte expressed gene-1 (DEC1) enhances the development of colorectal cancer with an involvement of the STAT3 signaling

Colorectal cancer (CRC) is the second deadly and the third most common malignancy worldwide. It has been projected that annual new cases of CRC will increase by 63% in 2040, constituting an even greater health challenge for decades to come. This study has linked DEC1 (differentiated embryonic chondrocyte expressed gene 1) to the pathogenesis of CRC. Based on the analysis of patient samples and database data, DEC1 is expressed much higher in CRC than the adjacent normal tissues. CRC patients with higher DEC1 expression have a shorter survival time. The carcinogenesis protocol with azoxymethane/dextran sulfate induces a higher number of tumors with larger sizes in DEC1^+/+ than DEC1^−/− mice. Overexpression of DEC1 increases the expression of proliferation- and antiapoptosis-related genes, but decreases the level of proapoptotic genes. Mechanistically, this study has shown that DEC1 is functionally looped to the IL-6/STAT3 signaling pathway (interleukin-6/signal transducer and activator of transcription 3). IL-6 induces DEC1, and DEC1 enhances the phosphorylation of STAT3, resulting in increased pSTAT3/STAT3 ratio. DEC1 and STAT3 are present in reciprocal immunocomplexes, pointing to physical interactions (presumably with pSTAT3). These findings establish that DEC1 is a CRC enhancer. The enhancement is achieved largely through the IL-6/STAT3 pathway. The potential of the physical interaction between DEC1 and STAT3 will likely serve as a foundation to develop intervention strategies for CRC prevention and therapy.

Sesquiterpene lactones from Xanthium sibiricum Patrin alleviate asthma by modulating the Th1/Th2 balance in a murine model

BACKGROUND

Asthma is a complex airway disease involving a variety of cells and cytokines. Xanthium sibiricum Patrin ex Widder (X. sibiricum) is a traditional Chinese medicine for various immune diseases, especially allergic rhinitis and asthma. Sesquiterpene lactones are the main bioactive and most abundant constituent, and are characteristic component of the plant. We explore whether sesquiterpene lactones from X. sibiricum (SL-XS) is the main active constitute for its anti-asthma activity.

PURPOSE

In the present study, SL-XS was isolated, the major compounds were isolated and identified in extract of SL-XS, and the anti-asthma activity of SL-XS was validated in vivo.

METHODS

SL-XS was isolated by a standard phytochemical method. The structures of major sesquiterpene lactones were identified by NMR and LC-MS spectra. The contents of major SL-XS were analyzed by HPLC. The anti-asthma effect of SL-XS was evaluated in a house dust mite (HDM)-induced mouse model.

RESULTS

The sesquiterpene lactones were isolated from X. sibiricum, and five major constituents i.e., 8‑epi-xanthatin-1β, 5β-epoxide (1), tomentosin (2), 8‑epi-xanthatin (3), 2‑epi-xanthumin (4) and sibiriolide B (5) were identified from SL-XS. Oral administration of SL-XS dose-dependently ameliorated airway inflammation and remodeling in HDM-challenged asthma mouse model. Furthermore, SL-XS treatment inhibited the upregulation of proinflammatory and Th2 cytokines, while reversed the downregulation of Th1 related cytokines. In addition, SL-XS regulated the balance between T-bet and GATA-3. Moreover, SL-XS inhibited the upregulation of JAK1, p-JAK1, JAK2, p-JAK2, JAK3, p-JAK3 and p-STAT6 in HDM-challenged mice.

CONCLUSION

The sesquiterpene lactones including five major constituents may be the main anti-asthma active constituent of X. sibiricum. SL-XS exerted its anti-asthma effect by modulating the Th1/Th2 balance via the JAK/STAT signaling pathway.

Drug affinity responsive target stability (DARTS) accelerated small molecules target discovery: Principles and application

Drug affinity responsive target stability (DARTS) is a novel target discovery approach and is particularly adept at screening small molecule (SM) targets without requiring any structural modifications. The DARTS method is capable of revealing drug-target interactions from cells or tissues by tracking changes in the stability of proteins acting as receptors of bioactive SMs. Due to its simple operation and high efficiency, the DARTS method has been applied to uncover the drug-action mechanism. This review summarized analytical principles, protocols, validation approaches, applications, and challenges involved in the DARTS method. Due to the innate advantages of the DARTS method, it is expected to be a powerful tool to accelerate SM target discovery, especially for bioactive natural products with unknown mechanisms.