Glaucocalyxin A delays the progression of OA by inhibiting NF-κB and MAPK signaling pathways.

BACKGROUND: Osteoarthritis (OA) is a common degenerative joint condition marked by inflammation and cartilage breakdown. Currently, there is a dearth of treatment medications that can clearly slow the course of OA. Glaucocalyxin A (GLA) is a diterpene chemical identified and extracted from Rabdosia japonica with antithrombotic, anticoagulant, anti-tumor, anti-inflammatory, anti-oxidant, and other pharmacological properties. Previous research has linked inflammation to abnormalities in the homeostasis of the extracellular matrix (ECM). Although GLA has been shown to have anti-inflammatory qualities, its effects on the progression of OA are unknown. As a result, the goal of this study was to see if GLA could slow the course of OA. METHODS: ATDC5 cells were stimulated by IL-1ß to create an inflammatory chondrocyte damage model. Quantitative polymerase chain reaction, Western Blot, high-density culture, and immunofluorescence were used to detect the expression levels of associated gene phenotypes. We also created a mouse model of OA induced by destabilization of the medial meniscus (DMM) instability, and GLA was administered intraperitoneally once every two days for eight weeks. Mice knee specimens were stained with hematoxylin-eosin, Safranin O/fast green, and immunohistochemical, and the Osteoarthritis Research Society International grade system and Mankin's score were used to assess the protective effect of GLA on cartilage. RESULTS: In vitro and in vivo, we explored the effects and molecular processes of GLA as a therapy for OA. The findings demonstrated that GLA might reduce the expression of associated inflammatory mediators and protect the ECM by inhibiting the NF-κB and MAPK signaling pathways. Animal research revealed that GLA could protect against the DMM-induced OA model mice by stabilizing ECM. CONCLUSION: Taken together, our findings show that GLA has a protective impact on cartilage throughout OA progression, implying that GLA could be employed as a possible therapeutic agent for OA, thus giving a new therapeutic method for the treatment of OA.

Chemoproteomics Reveals Glaucocalyxin A Induces Mitochondria-Dependent Apoptosis of Leukemia Cells via Covalently Binding to VDAC1.

Chronic myelogenous leukemia (CML) that is resistant to tyrosine kinase inhibitors is one of the deadliest hematologic malignancies, and the T315I mutation in the breakpoint cluster region-Abelson (BCR-ABL) kinase domain is the most prominent point mutation responsible for imatinib resistance in CML. Glaucocalyxin A (GLA), a natural bioactive product derived from the Rabdosia rubescens plant, has strong anticancer activity. In this study, the effect and molecular mechanism of GLA on imatinib-sensitive and imatinib-resistant CML cells harboring T315I mutation via a combined deconvolution strategy of chemoproteomics and label-free proteomics is investigated. The data demonstrated that GLA restrains proliferation and induces mitochondria-dependent apoptosis in both imatinib-sensitive and resistant CML cells. GLA covalently binds to the cysteine residues of mitochondrial voltage-dependent anion channels (VDACs), resulting in mitochondrial damage and overflow of intracellular apoptotic factors, eventually leading to apoptosis. In addition, the combination of GLA with elastin, a mitochondrial channel VDAC2/3 inhibitor, enhances mitochondria-dependent apoptosis in imatinib-sensitive and -resistant CML cells, representing a promising therapeutic approach for leukemia treatment. Taken together, the results show that GLA induces mitochondria-dependent apoptosis via covalently targeting VDACs in CML cells. GLA may thus be a candidate compound for the treatment of leukemia.

Glaucocalyxin A attenuates carbon tetrachloride-induced liver fibrosis and improves the associated gut microbiota imbalance.

Liver fibrosis refers to the pathophysiological process of dysplasia on the connective tissue of the liver, caused by a variety of pathogenic factors. Glaucocalyxin A (GLA) has anticoagulation, antibacterial, anti-inflammation, antioxidant and antitumour properties. However, whether GLA ameliorates liver fibrosis or not is still unclear. In this study, a liver fibrosis model was established using male C57BL/6 mice. The mice were treated with 5 and 10 mg/kg GLA via intraperitoneal injection, respectively. The ones that were treated with 5 mg/kg OCA were used as the positive control group. The levels of liver function, liver fibrosis biomarkers and liver pathological changes were then evaluated. We also explored the effects of GLA on inflammatory response and liver cell apoptosis. In addition, we investigated the gut microbiota mechanisms of GLA on liver fibrosis. The results from this study that GLA could significantly decrease the level of liver function (AST, ALT, TBA) and liver fibrosis (HA, LN, PC-III, IV-C). On the other hand, a significant decrease in inflammation levels (IL-1ß, TNF-α) were also noted. GLA also improves CCl4-induced pathological liver injuries and collagen deposition, in addition to decreasing apoptosis levels. In addition, an increase in the ratio of Bacteroidetes and Firmicutes in liver disease was also observed. GLA also improves the gut microbiota. In conclusion, GLA attenuates CCl4-induced liver fibrosis and improves the associated gut microbiota imbalance.

Glaucocalyxin A Inhibits the Malignant Progression of Epithelial Ovarian Cancer by Affecting the MicroRNA-374b-5p/HMGB3/Wnt-ß-Catenin Pathway Axis.

Objective: Glaucocalyxin A (GLA) is an ent-kaurene diterpenoid from Rabdosia japonica var possessing anti-tumor activity. This study aimed to investigate effects of GLA on epithelial ovarian cancer (EOC) and elucidate underlying mechanisms. Methods: The expression of HMGB3 in EOC tissues was analyzed by GEPIA and immunohistochemistry. Cell proliferation was determined using CCK-8 and colony formation assays. Cell invasion, migration, and apoptosis were detected using Transwell, wound healing, and flow cytometry assays, respectively. Interactions between HMGB3 and miRNAs were predicted using ENCORI and validated using a dual-luciferase assay. mRNA expression levels of HMGB3 and miRNAs were measured using qPCR. Protein expression levels of HMGB3, E-cadherin, N-cadherin, Wnt3a,ß-catenin, Bcl-2, and Bax were measured by western blotting. A tumor xenograft model was established to validate the efficacy and mechanism of GLA in vivo. Results: HMGB3 was upregulated in EOC tissues and cells. GLA dose-dependently inhibited EOC cell proliferation and epithelial-mesenchymal transition (EMT). HMGB3 overexpression promoted proliferation, invasion, migration, and EMT, and suppressed the apoptosis of EOC cells. In addition, miR-374b-5p was targeted by HMGB3, and its overexpression hindered malignant characteristics of EOC cells. HMGB3 overexpression weakened antitumor effects of GLA and miR-374b-5p in EOC cells. Moreover, the Wnt-ß-catenin pathway was inhibited by the GLA-mediated miR-374b-5p/HMGB3 axis. In vivo experiments showed that GLA inhibited EOC tumor growth, meanwhile, upregulated the miR-374b-5p level and downregulated the expression of HMGB3, Wnt3a, and ß-catenin in tumor tissues. Conclusions: GLA suppressed the malignant progression of EOC by regulating the miR-374b-5p/HMGB3/Wnt-ß-catenin pathway axis.

Protective effects of glaucocalyxin A on the airway of asthmatic mice.

The aim of this study is to investigate the protective effects of glaucocalyxin A (GLA) on airways in mouse models of asthma, concerning the inflammatory mediators, Th1/Th2 subgroup imbalance, and Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Hematoxylin and eosin/periodic acid-Schiff staining was used to observe the pathological changes in lung tissues. Inflammatory cytokine contents in the bronchoalveolar lavage fluid were detected by enzyme-linked immunosorbent assay. Protein expression levels were detected with Western blot, immunohistochemistry, and immunofluorescence. In vivo studies showed that, in ovalbumin (OVA)-induced asthmatic mouse models, the GLA treatments reduced the airway hyperresponsiveness and the secretion of inflammatory cells, declined the proliferation of goblet cells, decreased the levels of IL-4, IL-5, and IL-13, and increased the contents of interferon-γ and IL-12. Moreover, GLA inhibited the protein expression levels of TLR4, MyD88, TRAF6, and NF-κB in OVA-induced asthmatic mouse models. Further in vitro studies showed that GLA inhibited the expression of NF-κB, p-IκBα, tumor necrosis factor-α, IL-6, and IL-1ß and blocked the nuclear transfer of NF-κB in lipopolysaccharide-stimulated RAW264.7 macrophages. Conclusively, GLA can inhibit the inflammatory responses in OVA-induced asthmatic mice and inhibit the release of inflammatory factors in LPS-induced RAW264.7 macrophages, which may be related to the inhibition of TLR4/NF-κB signaling pathway.

Glaucocalyxin A Inhibits the Malignancies of Gastric Cancer Cells by Downregulating MDM2 and RNF6 via MiR-3658 and the SMG1-UPF mRNA Decay Pathway.

Gastric cancer (GC) ranks as the most common gastrointestinal cancer and is among the leading causes of cancer death worldwide. Glaucocalyxin A (GLA), an entkauranoid diterpene isolated from Rab-dosia japonica var., possesses various bioactivities. To date, the data on the effect of GLA on GC are still minimal, and the molecular mechanisms remain largely unknown. Herein, we found that GLA could significantly inhibit the proliferation, cell adhesion, and invasion of HGT-1, SNU-1, SNU-6, and NCI-N87 GC cells in a dose-dependent manner. GLA enhanced the apoptosis of the GC cells as evidenced by the increased caspase-3 activity and the elevated levels of cleaved caspase-3 and cleaved PARP in GC cells in the presence of GLA. We then showed that the downregulation of Murine Double Minute Clone 2 (MDM2) and Ring Finger Protein 6 (RNF6) by GLA was implicated in the GLA-induced inhibition of the GC cells. Furthermore, MDM2 and RNF6 were identified as the targets of miR-3658 that was downregulated in the GC cells and upregulated by GLA. Moreover, it was shown that miR-3658 was hypermethylated in the GC cells, and GLA could rescue the expression of miR-3658 via demethylation by abrogating EZH2-mediated epigenetic silencing. In addition to the miR-3658-MDM2/RNF6 regulatory axis, activation of the SMG1-UPF mRNA decay pathway contributed to the downregulation of MDM2 and RNF6 by GLA in the GC cells. The inhibitory effect of GLA on gastric cancer and the expression of MDM2 and RNF6 was also validated in in vivo study. Our findings suggest that has the therapeutic potential for GC by downregulating oncogenes via posttranscriptional regulation.

Glaucocalyxin A induces apoptosis of non-small cell lung carcinoma cells by inhibiting the PI3K/Akt/GSK3ß pathway.

Lung cancer is one of the fastest growing malignancies in morbidity and mortality, and current therapies are in general not sufficiently effective for this deadly disease. This study characterizes the anticancer effects of glaucocalyxin A (GLA) and explores the underlying mechanisms using human non-small cell lung carcinoma (NSCLC) cells. First, our data showed that GLA suppressed the viability of cancer cells, whereas no effect was observed in the normal bronchial epithelial cell BEAS-2B cells. Second, GLA inhibited colony formation, induced apoptosis of cancer cells. Third, GLA downregulated the expression of B-cell lymphoma-2 (Bcl-2) protein; upregulated the expression of Bcl2-associated X protein (Bax), and strengthened cleavage of caspase 3 and polyadenyl diphosphate ribose polymerase (PARP). Fourth, GLA also diminished mitochondrial membrane potential and inhibited phosphatidylinositol 3-kinase (PI3K)/Akt/ glycogen synthase kinase-3ß (GSK3ß) pathway. In addition, injection of GLA (20 mg/kg) every 2 days significantly inhibited A549 xenograft tumour growth, accompanied by increased apoptosis and decreased proliferation. Together, our study provides evidence that the anticancer effect of GLA in NSCLC is mediated by inducing apoptosis through inhibiting PI3K/Akt/GSK3ß pathway and suggests that GLA may be used as a promising natural medicine for NSCLC therapy.

Glaucocalyxin A alleviates lipopolysaccharide-induced inflammation and apoptosis in pulmonary microvascular endothelial cells and permeability injury by inhibiting STAT3 signaling.

Glaucocalyxin A (GLA), an ent-kauranoid diterpene derived from Rabdosia japonica var. glaucocalyx, possesses antibacterial, anti-oxidative and anti-neuroinflammatory properties. The present study aimed to investigate the potential mechanisms underlying GLA in the pathogenesis of pneumonia. Human pulmonary microvascular endothelial cells (hPMVECs) treated with lipopolysaccharide (LPS) were treated with GLA, followed by the detection of cell viability, inflammation, apoptosis and cell permeability. Furthermore, the protein expression levels of apoptosis- and permeability-associated proteins were determined using western blot analysis. Following treatment with a signal transducer and activator of transcription 3 (STAT3) activator, the protein expression levels of STAT3 and endoplasmic reticulum stress-associated proteins were determined, to confirm whether STAT3 signaling was mediated by GLA. Lastly, the mRNA expression level of inflammatory cytokines, apoptosis and permeability injury were also determined following treatment with a STAT3 activator. The results revealed that GLA ameliorated inflammation, apoptosis and permeability injury in LPS-induced hPMVECs. Following treatment with a STAT3 activator, the therapeutic effects of GLA on LPS-induced hPMVECs were abrogated. In conclusion, GLA alleviated LPS-induced inflammation, apoptosis and permeability injury in hPMVECs by inhibiting STAT3 signaling, which highlighted the potential therapeutic value of GLA in the treatment of pneumonia.

Glaucocalyxin A impairs tumor growth via amplification of the ATF4/CHOP/CHAC1 cascade in human oral squamous cell carcinoma.

ETHNOPHARMACOLOGICAL RELEVANCE: The natural extract glaucocalyxin A (GLA), purified from the aboveground sections of the Chinese traditional medicinal herb Rabdosia japonica (Burm. f.) Hara var. glaucocalyx (Maxim.) Hara, has various pharmacological benefits, such as anti-bacterial, anti-coagulative, anti-neoplastic, and anti-inflammatory activities. Although GLA has shown anti-tumor activity against various cancers, the therapeutic potential and biological mechanisms of GLA remain to be further explored in oral squamous cell carcinoma (OSCC). AIM OF THE STUDY: This study aimed to elucidate the therapeutic potential and regulatory mechanisms of GLA in OSCC. MATERIALS AND METHODS: The cell proliferation and apoptosis effects of GLA were analyzed by CCK-8, clone formation, Annexin V/PI staining, and apoptotic protein expression in vitro. An OSCC xenograft model was applied to confirm the anti-neoplastic effect in vivo. Furthermore, the changes of reactive oxygen species (ROS) were determined by DCFH-DA probe and GSH/GSSG assay, and inhibited by the pan-caspase inhibitor Z-VAD(OMe)-FMK and the ROS scavenger N-acetylcysteine (NAC). The modulation of GLA on mitochondria and ER-dependent apoptosis pathways was analyzed by JC-1 probe, quantitative real-time PCR, and Western blot. Finally, public databases, clinical samples, and transfection cells were analyzed to explore the importance of GLA's indirect targeting molecule CHAC1 in OSCC. RESULTS: GLA significantly inhibited cell proliferation and induced apoptosis in vitro and in vivo. GLA perturbed the redox homeostasis, and cell apoptosis was totally rescued by Z-VAD(OMe)-FMK and NAC. Furthermore, GLA activated the mitochondrial apoptosis pathway. Simultaneously, the overexpression and knockdown of CHAC1 dramatically affected GLA-mediated apoptosis. The endoplasmic reticulum stress-associated ATF4/CHOP signal was identified to participate in GLA-upregulated CHAC1 expression. Finally, we found that CHAC1 expression was lower in OSCC compared with normal tissues and positively correlated with 4-Hydroxynonenal (4-HNE) level. High CHAC1 expression also indicated better overall survival. Moreover, CHAC1 selectively regulated the viability of oral cancer cells. CONCLUSION: GLA is a promising therapeutic agent that activates the ROS-mediated ATF4/CHOP/CHAC1 axis in OSCC patients.

Glaucocalyxin a prevents hypoxia-induced epithelial-mesenchymal transition in human gastric cancer cells through the PI3K/Akt signaling pathway.

Hypoxia is a frequent occurrence in most solid tumors and associated with multiple cancer progression. Glaucocalyxin A (GLA) has been found to exhibit anti-tumor effect in several types of cancer, except gastric cancer (GC). The present study aimed to evaluate the function of GLA in GC and explore the underlying mechanism under hypoxia condition. Our results showed that GLA suppressed cell viability of MGC-803 cells in both normoxic or hypoxic conditions. MGC-803 cells were more sensitive to GLA in hypoxic condition. GLA attenuated hypoxia-induced migration and invasion of GC cells. Western blot assay proved that GLA elevated E-cadherin expression, as well reduced N-cadherin and vimentin expressions in hypoxia-induced GC cells. Moreover, we also found that GLA suppressed the expression of HIF-1α in both mRNA and protein levels. Furthermore, GLA blocked hypoxia-induced activation of PI3K/Akt pathway in GC cells. Notably, insulin like growth factor 1 (IGF-1), an activator of PI3K/Akt pathway, reversed the effects of GLA on cell migration, invasion and EMT in hypoxia-treated MGC-803 cells. In conclusion, these findings demonstrated that GLA exerted inhibitory effects on cell migration, invasion and epithelial to mesenchymal transition (EMT) via the PI3K/Akt signaling pathway in GC cells.

Study on regulation mechanism of glaucocalyxin A on the autophagy and apoptosis of HCCLM 3 hepatocellular carcinoma cells through Bcl- 2/Beclin1 target / 中国药房

OBJECTIVE To study the regulator y mech anism of glaucocalyxin A （GLA） on autophagy and apoptosis of HCCLM3 hepatocellular carcinoma cells. METHODS HCCLM3 cells were taken ，and control group ，GLA 2.5 μg/mL group，GLA 5 μg/mL group and GLA 10 μg/mL group were mainly set according to different experimental purposes. In control group，only complete medium was added ；in each administration group ，complete medium containing the corresponding final concentration of GLA was added. Cell cycle distribution and apoptosis were detected by flow cytometry ；mitochondrial morphology and autophagy were observed by transmission electron microscope （only control group ，GLA 5 μg/mL group）；JC-1 staining and fluorescence inverted microscope were used to observe and detect the mitochondrial membrane potential of the cells ；Western blot assay was used to detect the protein expression of Bcl- 2， Bax， Beclin1 and cleaved caspase- 3 proteins in the cells ； the co-immunoprecipitation method was used to detect the binding and dissociation of Bcl- 2 and Beclin 1（only GLA 5 μg/mL group， GLA 10 μg/mL group）. RESULTS Compared with control group ，GLA 5 μg/mL and GLA 10 μg/mL could induce a significant arrest of the cell cycle in the G 2-M phase for HCCLM 3，a significant decrease in mitochondrial membrane potential ，an increase in apoptosis as well as significant promotion of the protein expression of Bax ，cleaved caspase- 3 and Beclin 1，and significant inhibition of the protein expression of Bcl- 2（P＜0.01）. GLA 5 μg/mL also significantly changed mitochondrial morphology and increased autophagosomes. The results of co-immunoprecipitation showed that compared with GLA 5 μg/mL，GLA 10 μg/mL could enhance the binding of Bcl- 2 and Beclin 1. CONCLUSIONS GLA can regulate the autophagy and apoptosis of HCCLM 3 cells by Bcl-2/Beclin1 target. The effect is closely related to the dose of GLA.

Glaucocalyxin A suppresses multiple myeloma progression in vitro and in vivo through inhibiting the activation of STAT3 signaling pathway.

BACKGROUND: Multiple myeloma (MM) is the most common malignant hematological disease in the people worldwide. Glaucocalyxin A (GLA) is a bioactive ent-kauranoid diterpenoid, that is derived from Rabdosia japonica var. GLA has been demonstrated that it had various pharmacological activities, such as anti-coagulation, anti-bacterial, anti-tumor, anti-inflammation, antioxidant activities. Although GLA has effective anti-tumor properties, its effects on multiple myeloma remain unclear. The aim of this study was to examine the possible anti-cancer effects of GLA and their molecular mechanisms on MM cells in vitro and in vivo. METHODS: To evaluate the role of GLA on the proliferation of MM cells in vitro and in vivo, we used MTT method to detect the role of GLA on the proliferation of MM cells. Cell apoptosis and cell cycle assay were evaluated by flow cytometry. Protein expressions in GLA-treated and untreated MM cells were evaluated by western blot analyses. MM xenograft nude mice model was used to investigate the role of GLA on the proliferation of MM cells in vivo. IHC assay was used to examine the role of GLA on the MM xenograft model in vivo. RESULTS: In the present study, we firstly reported the potent anti-myeloma activity of GLA on MM cells. We found that GLA could induce apoptosis in vitro and in vivo. GLA could inhibit the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) and downregulate interleukin IL-6 induced STAT3 phosphorylation in MM. Overexpression of STAT3 could significantly prevent apoptosis induced by GLA; while knockdown of STAT3 enhanced it. Moreover, GLA could inhibit cell proliferation by inducing the cell cycle arrest. GLA reduced the expression of cell cycle-related proteins CCNB1, CCND1, CCND2, and CCND3 and increased the expression of p21 in MM cell lines. In addition, in the MM xenograft nude mice model, GLA exhibited very good anti-myeloma activity. Administration of GLA almost completely inhibited tumor growth within 19 days without physical toxicity. And the IHC results showed GLA significantly inhibited cell proliferation and interfered STAT3 pathway on MM xenograft model tumor tissues. CONCLUSIONS: Taken together, our present research indicated that GLA inhibits the MM cell proliferation, induces MM cell apoptosis and cell cycle arrest through blocking the activation of STAT3 pathway. Thus, GLA may be a potential therapeutic candidate for MM patients in the future.

Glaucocalyxin A suppresses osteoclastogenesis induced by RANKL and osteoporosis induced by ovariectomy by inhibiting the NF-κB and Akt pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Glaucocalyxin A (GLA), the most abundant active component of the aboveground sections of Rabdosia japonica (Burm. f.) Hara var. glaucocalyx (Maxim.) Hara, possesses various pharmacological activities, such as antioxidant, antithrombosis, anticoagulation, antibacterial, antitumor, anti-inflammatory activities. According to previous studies, inflammation is closely associated with osteoclast differentiation and activity. Although GLA has demonstrated effective anti-inflammatory properties, its effects on osteoclast differentiation remain unclear. AIM OF THE STUDY: To examine the possible inhibitory effects of GLA and its molecular mechanisms in osteogenesis induced by RANKL as well as ovariectomy (OVX)-induced osteoporosis (OP) in mice. MATERIALS AND METHODS: Tartrate-resistant acid phosphatase (TRAP) staining, F-actin staining, and a bone resorption pit assay were applied for identifying the effects of GLA on the differentiation of osteoclasts and the function of bone resorption. The mRNA expression of the genes related to osteoclast differentiation was measured by quantitative PCR. Protein expression of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), c-fos and phosphorylation of inhibitor of nuclear factor kappa B (IκBα), protein kinase B (AKT), c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 in RANKL-induced osteoclasts was determined using western blotting. The effect of GLA on OP was studied using a mouse model of OVX. RESULTS: At nontoxic concentrations ≤0.5 µM in vitro, GLA suppressed the formation of osteoclasts induced by RANKL with the decreased number and area size of TRAP-positive multinuclear osteoclasts, and the resorption of bone function by reducing F-actin ring number and bone resorption pit areas. It also reduced the expression of the genes specific for osteoclasts, which included genes encoding NFATc1, cathepsin K, c-fos, TRAP, vacuolar-type ATPase d2, and dendritic cell-specific transmembrane protein. Moreover, GLA repressed NF-κB and Akt pathway activation induced by RANKL. Micro-CT analysis of femur samples indicated decreased bone loss and greater trabecular bone density after GLA treatment, which showed that GLA played a protective role by inhibiting bone loss in OVX-induced OP mice in vivo. CONCLUSIONS: Our study is the first to show that GLA has significant therapeutic potential in OP, which is the disease of osteoclast increase caused by estrogen deficiency.

Glaucocalyxin A suppresses inflammatory responses and induces apoptosis in TNF-a-induced human rheumatoid arthritis via modulation of the STAT3 pathway.

The pathogenesis of rheumatoid arthritis (RA) is characterized by synoviocyte hyperplasia and proinflammatory cytokine secretion, as well as the destruction of cartilage and bone. Glaucocalyxin A (GLA) is an alkaloid derived from a Chinese medicinal plant that exhibits anti-inflammatory, anti-tumor and neuroprotective properties. We investigated the effects of GLA on RA-fibroblast-like synoviocytes (FLS cells), and collagen-induced arthritis (CIA), and further explored the underlying mechanisms. GLA inhibited TNF-a-induced RA-FLS proliferation, increased apoptotic ratios and upregulated levels of caspase-3, cleaved PARP, and Bax. GLA also inhibited the expression of IL-10, IL-1ß, and IL-6 in vitro. Levels of p-STAT3 were downregulated in a dose-dependent manner. Over-expression of STAT3 partly neutralized the GLA-mediated elevation of caspase-3 and cleaved PARP levels as well as the downregulation of IL-10, IL-1B and IL-6 expression levels. This suggests that GLA inactivated the STAT3 pathway. Furthermore, the production of inflammatory cytokines in RA-FLS and a CIA rat model were inhibited effectively by GLA. Taken together, our data suggest that GLA is a potential long-term therapeutic agent for patients with RA.

Glaucocalyxin A induces apoptosis and autophagy in tongue squamous cell carcinoma cells by regulating ROS.

PURPOSE: Tongue squamous cell carcinoma (TSCC) is the most common highly invasive oral cancer. Glaucocalyxin A (GLA) is a diterpenoid component isolated from Rabdosia japonica var. with anti-bacterial and anti-cancer biological properties. However, the role of GLA in human TSCC remains uncertain. The aim of this paper was to investigate the anti-cancer effect of GLA on TSCC cells as well as its underlying mechanism. METHODS: Cell viability and growth were analyzed by CCK-8 assay and colony formation, respectively. DAPI staining and flow cytometry assay were used to detect the cell apoptosis. Lysotracker Red staining was used to observe the lysosomes and autolysosomes of TSCC cells. ROS fluorescent probe was used to test the intracellular ROS levels. Western blotting was used to detect the expression levels of apoptosis- and autophagy-related proteins. RESULTS: GLA inhibits the cell viability and growth in TSCC cells. GLA induces TSCC cells apoptosis, autophagy and ROS production in a time- and concentration-dependent manner. In addition, GLA inhibits the viability of TSCC cells by inducing intracellular ROS production. Finally, GLA triggers ROS-dependent apoptosis and autophagy in TSCC cells. CONCLUSION: Our results consistently suggested that GLA can induce apoptosis and autophagy in TSCC cells by generating ROS. GLA may serve as a promising therapeutic drug for overcoming TSCC.

Glaucocalyxin A induces cell cycle arrest and apoptosis via inhibiting NF-κB/p65 signaling pathway in melanoma cells.

AIMS: Melanoma is a malignant tumor of the skin with a high metastasis rate and poor prognosis. Glaucocalyxin A (GLA), isolated from Rabdosia japonica, is a diterpenoid compound with anticancer properties. Here, we investigated the anticancer properties and explored the mechanisms underlying GLA activity in melanoma cells in vitro and in vivo. MAIN METHODS: Cell Counting Kit-8 and colony formation assays were used to assess the effects of GLA on cell proliferation. Flow cytometry was used to evaluate the cell cycle, apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS), and western blot analysis and immunofluorescence staining were used to examine protein expression. Immunohistochemical analysis was performed to examine animal tissues and tumors in mice. KEY FINDINGS: GLA could effectively inhibit cell proliferation and induce cell apoptosis. GLA induced an overproduction of cellular ROS, decreased MMP, and upregulated the Bax/Bcl-2 ratio, which is an indicator of apoptosis. Phosphorylation of nuclear factor κB (NF-κB)/p65 and NF-κB/p65 nuclear expression decreased after GLA treatment in vitro and in vivo, suggesting that the anticancer effects of GLA are mediated through the NF-κB/p65 pathway. Moreover, we observed that GLA was effective in inhibiting tumor growth without obvious toxicity to major organs in mice. SIGNIFICANCE: This is the first study to show that GLA inhibits cell proliferation, arrests the cell cycle in the G2/M phase, and induces mitochondrial apoptosis via the NF-κB/p65 pathway in melanoma cells. Overall, our results demonstrate that GLA may be a potential anticancer agent for the treatment of melanoma.

Glaucocalyxin A Ameliorates Hypoxia/Reoxygenation-Induced Injury in Human Renal Proximal Tubular Epithelial Cell Line HK-2 Cells.

Ischemia-reperfusion injury is one of the major causes of acute kidney injury (AKI), which is increasingly prevalent in clinical settings. Glaucocalxin A (GLA), a biologically ent-kauranoid diterpenoid, has various pharmacological effects like antioxidation, immune regulation, and antiatherosclerosis. In this study, the effect of GLA on AKI and its mechanism were studied in vitro. HK-2 human renal tubular epithelial cells were exposed to hypoxia/reoxygenation (H/R), which were established as an in vitro AKI model. Subsequently, the mRNA expressions of inflammatory and antioxidant factors were determined by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Reactive oxygen species (ROS) production and cell death were detected by fluorescence-activated cell sorting. GLA pre-treatment improved the cell viability of HK-2 cells exposed to H/R. GLA suppressed the H/R-induced ROS production in HK-2 cells. GLA also elevated the activities of superoxide dismutase of HK-2 cells exposed to H/R. Moreover, GLA prevented H/R-induced cell death in HK-2 cells. Furthermore, GLA ameliorated the activation of the protein kinase B (Akt)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in HK-2 cells exposed to H/R. Our findings suggested that GLA protected HK-2 cells from H/R-induced oxidative damage, which was mediated by the Akt/Nrf2/HO-1 signaling pathway. These results indicate that GLA may serve as a promising therapeutic drug for AKI.

Activation of Nrf2/HO-1 signaling: An important molecular mechanism of herbal medicine in the treatment of atherosclerosis via the protection of vascular endothelial cells from oxidative stress.

Introduction: Recently, Nrf2/HO-1 has received extensive attention as the main regulatory pathway of intracellular defense against oxidative stress and is considered an ideal target for alleviating endothelial cell (EC) injury. Objectives: This paper aimed to summarized the natural monomers/extracts that potentially exert protective effects against oxidative stress in ECs. Methods: A literature search was carried out regarding our topic with the keywords of "atherosclerosis" or "Nrf2/HO-1" or "vascular endothelial cells" or "oxidative stress" or "Herbal medicine" or "natural products" or "natural extracts" or "natural compounds" or "traditional Chinese medicines" based on classic books of herbal medicine and scientific databases including Pubmed, SciFinder, Scopus, the Web of Science, GoogleScholar, BaiduScholar, and others. Then, we analyzed the possible molecular mechanisms for different types of natural compounds in the treatment of atherosclerosis via the protection of vascular endothelial cells from oxidative stress. In addition, perspectives for possible future studies are discussed. Results: These agents with protective effects against oxidative stress in ECs mainly include phenylpropanoids, flavonoids, terpenoids, and alkaloids. Most of these agents alleviate cell apoptosis in ECs due to oxidative stress, and the mechanisms are related to Nrf2/HO-1 signaling activation. However, despite continued progress in research on various aspects of natural agents exerting protective effects against EC injury by activating Nrf2/HO-1 signaling, the development of new drugs for the treatment of atherosclerosis (AS) and other CVDs based on these agents will require more detailed preclinical and clinical studies. Conclusion: Our present paper provides updated information of natural agents with protective activities on ECs against oxidative stress by activating Nrf2/HO-1. We hope this review will provide some directions for the further development of novel candidate drugs from natural agents for the treatment of AS and other CVDs.

Synthesis and in vitro anticancer activities of biotinylated derivatives of glaucocalyxin A and oridonin.

Fourteen glaucocalyxin A biotinylated derivatives, one glaucocalyxin C biotinylated derivative, and two oridonin biotinylated derivatives were designed and synthesized. Their structures were confirmed from 1H NMR, 13C NMR and HRMS data. The derivatives were evaluated for cytotoxic activities against lung (A549), cervical cancer cell line HeLa derivative (KB), multidrug-resistant KB subline (KB-VIN), triple-negative breast (MDA-MB-231), and estrogen receptor-positive breast (MCF-7) cancer cell lines.[Formula: see text].

Glaucocalyxin A attenuates allergic responses by inhibiting mast cell degranulation through HMGB1/TLR4/NF-κB signaling pathways / 药学学报

The study is to investigate the effect of glaucocalyxin A (GLA) on mast cell-mediated anaphylaxis. The animal welfare and experimental process of this experiment followed the regulations of the Animal Ethics Committee of Yanbian University. BALB/c mice were used in the animal experiment and randomly divided into five groups, control group, model group, and GLA low, medium, and high dose groups (10, 20, and 40 mg·kg-1). Mice were sensitized by intradermal injection of anti-dinitrophenyl-immunoglobulin E (DNP-IgE) into the ears and challenged with a mixture of DNP-human serum albumin (HSA) and 4% evans blue into the tail veins to prepare an animal skin passive cutaneous anaphylaxis (PCA) model, which was collected from both ears for measurement of dye staining and histology. Rat peritoneal mast cells (RPMCs) were used in the cell experiment and divided into control, IgE + antigen (Ag), and IgE + Ag + GLA groups to determine histamine release as well as calcium influx levels. High-affinity IgE receptor (FcεRI)-mediated signaling pathway proteins and HMGB1/TLR4/NF-κB (high mobility group box 1/toll like receptor 4/nuclear transcription factor kappa B) signaling proteins were detected by Western blot. The results of animal experiments suggest that GLA inhibits PCA, reduces evans blue dye exudation, and reduces ear inflammation and ear thickness in mice. The results of cellular experiments suggested that GLA could reduce histamine release and calcium influx, and inhibit tumor necrosis factor-α (TNF-α), interleukin (IL)-4, IL-13, and IL-1β production; Western blot results showed that GLA inhibited FcεRI-mediated phosphorylation levels of spleen tyrosine kinase (Syk), Lck/Yes novel tyrosine kinase (Lyn), tyrosine kinase Fyn (Fyn), growth-factor receptor-bound protein 2 (Gab2), and phospholipase C (PLC) γ1, while GLA inhibited HMGB1/TLR4 signaling pathway to limit NF-κB p65 nuclear metastasis. The results indicate that GLA inhibits mast cell degranulation and attenuates allergic inflammation through the HMGB1/TLR4/NF-κB signaling pathway.