Ginkgetin inhibits growth of breast carcinoma via regulating MAPKs pathway

The role of Ginkgo Folium on antitumor: Bioactive constituents and the potential mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. is a well-known and highly regarded resource in Chinese traditional medicine due to its effectiveness and safety. Ginkgo Folium, the leaf of Ginkgo biloba L., contains biologically active constituents with diverse pharmacological activities. Recent studies have shown promising antitumor effects of the bioactive constituents found in Ginkgo Folium against various types of cancer cells, highlighting its potential as a natural source of antitumor agents. Further research is needed to elucidate the underlying mechanisms and optimize its therapeutic potential.

AIM OF THE REVIEW

To provide a detailed understanding of the pharmacological activities of Ginkgo Folium and its potential therapeutic benefits for cancer patients.

MATERIALS AND METHODS

In this study, we conducted a thorough and systematic search of multiple online databases, including PubMed, Web of Science, Medline, using relevant keywords such as "Ginkgo Folium," "flavonoids," "terpenoids," "Ginkgo Folium extracts," and "antitumor" to cover a broad range of studies that could inform our review. Additionally, we followed a rigorous selection process to ensure that the studies included in our review met the predetermined inclusion criteria.

RESULTS

The active constituents of Ginkgo Folium primarily consist of flavonoids and terpenoids, with quercetin, kaempferol, isorhamnetin, ginkgolides, and bilobalide being the major compounds. These active constituents exert their antitumor effects through crucial biological events such as apoptosis, cell cycle arrest, autophagy, and inhibition of invasion and metastasis via modulating diverse signaling pathways. During the process of apoptosis, active constituents primarily exert their effects by modulating the caspase-8 mediated death receptor pathway and caspase-9 mediated mitochondrial pathway via regulating specific signaling pathways. Furthermore, by modulating multiple signaling pathways, active constituents effectively induce G1, G0/G1, G2, and G2/M phase arrest. Among these, the pathways associated with G2/M phase arrest are particularly extensive, with the cyclin-dependent kinases (CDKs) being most involved. Moreover, active constituents primarily mediate autophagy by modulating certain inflammatory factors and stressors, facilitating the fusion stage between autophagosomes and lysosomes. Additionally, through the modulation of specific chemokines and matrix metalloproteinases, active constituents effectively inhibit the processes of epithelial-mesenchymal transition (EMT) and angiogenesis, exerting a significant impact on cellular invasion and migration. Synergistic effects are observed among the active constituents, particularly quercetin and kaempferol.

CONCLUSION

Active components derived from Ginkgo Folium demonstrate a comprehensive antitumor effect across various levels and pathways, presenting compelling evidence for their potential in new drug development. However, in order to facilitate their broad and adaptable clinical application, further extensive experimental investigations are required to thoroughly explore their efficacy, safety, and underlying mechanisms of action.

Role of TBK1 Inhibition in Targeted Therapy of Cancer

TANK-binding kinase 1 (TBK1) is a serine/threonine protein that plays a crucial role in various biological processes like immunity, autophagy, cell survival, and proliferation. The level and kinase activity of the TBK1 protein is regulated through post-translational modifications (PTMs). TBK1 mainly mediates the activation of IRF3/7 and NF-κB signaling pathways while also participating in the regulation of cellular activities such as autophagy, mitochondrial metabolism, and cell proliferation. TBK1 regulates immune, metabolic, inflammatory, and tumor occurrence and development within the body through these cellular activities. TBK1 kinase has emerged as a promising therapeutic target for tumor immunity. However, its molecular mechanism of action remains largely unknown. The identification of selective TBK1 small molecule inhibitors can serve as valuable tools for investigating the biological function of TBK1 protein and also as potential drug candidates for tumor immunotherapy. The current research progress indicates that some TBK1 inhibitors (compounds 15,16 and 21) exhibit certain antitumor effects in vitro culture systems. Here, we summarize the mechanism of action of TBK1 in tumors in recent years and the progress of small molecule inhibitors of TBK1.

Ginkgetin Alleviates Intervertebral Disc Degeneration by Inhibiting Apoptosis, Inflammation, and Disturbance of Extracellular Matrix Synthesis and Catabolism via Inactivation of NLRP3 Inflammasome

BACKGROUND

Apoptosis, inflammation, and the extracellular matrix (ECM) synthesis and catabolism are compromised with intervertebral disc degeneration (IDD). Ginkgetin (GK) has been demonstrated to alleviate several diseases; however, its effect on IDD remains unknown.

METHODS

The nucleus pulposus cells (NPCs) were stimulated with interleukin (IL)-1β to construct the IDD models in vitro. Rats were used for the construction of the IDD models in vivo via the fibrous ring puncture method. The effect and mechanism of GK on IDD were determined by cell counting kit-8 (CCK-8), flow cytometry, western blot, real-time quantitative polymerase chain reaction (RT-qPCR), enzyme‑linked immunosorbent assay (ELISA), hematoxylin and eosin (HE) and safranine O staining, and immunohistochemistry (IHC) assays, respectively.

RESULTS

GK increased the cell viability and upregulated the expressions of anti-apoptosis and ECM synthesis markers in NPCs treated with IL-1β. GK also decreased apoptosis rate, and downregulated the expressions of proteins related to pro-apoptosis, ECM catabolism, and inflammation in vitro. Mechanically, GK reduced the expression of nucleotide binding oligomeric domain like receptor protein 3 (NLRP3) inflammasome-related proteins. Overexpression of NLRP3 reversed the effect of GK on the proliferation, apoptosis, inflammation, and ECM degradation in IL-1β-induced NPCs. Moreover, GK attenuated the pathological manifestations, inflammation, ECM degradation, and NLRP3 inflammasome expression in IDD rats.

CONCLUSION

GK suppressed apoptosis, inflammation, and ECM degradation to alleviate IDD via the inactivation of NLRP3 inflammasome.

Ginkgetin suppresses ovarian cancer growth through inhibition of JAK2/STAT3 and MAPKs signaling pathways

BACKGROUND

Ginkgo biloba L., a kind of traditional Chinese medicine, is always used to treat various diseases. Ginkgetin is an active biflavonoid isolated from leaves of Ginkgo biloba L., which exhibits diverse biological activities, including anti-tumor, anti-microbial, anti-cardiovascular and cerebrovascular diseases, and anti-inflammatory effects. However, there are few reports on the effects of ginkgetin on ovarian cancer (OC).

HYPOTHESIS/PURPOSE

OC is one of the most common cancers with high mortality in women. The purpose of this study was to find out how ginkgetin inhibited OC and which signal transduction pathways was involved to suppress OC.

METHODS

The OC cell lines, A2780, SK-OV-3 and CP70, were used for in vitro experiments. MTT assay, colony formation, apoptosis assay, scratch wound assay and cell invasion assay were used to determine the inhibitory effect of ginkgetin. BALB/c nude female mice were injected with A2780 cells subcutaneously, then treated with ginkgetin by intragastric administration. Western blot experiment was used to verify the inhibitory mechanism of OC in vitro and in vivo.

RESULTS

We found that ginkgetin inhibited the proliferation and induced apoptosis in OC cells. In addition, ginkgetin reduced migration and invasion of OC cells. In vivo study showed that ginkgetin significantly reduced tumor volume in the xenograft mouse model. Furthermore, the anti-tumor effects of ginkgetin were associated with a down regulation of p-STAT3, p-ERK and SIRT1 both in vitro and in vivo.

CONCLUSION

Our results suggest that ginkgetin exhibits anti-tumor activity in OC cells via inhibiting the JAK2/STAT3 and MAPK pathways and SIRT1 protein. Ginkgetin could be a potential candidate for the treatment of OC.

Comparative Inhibitory Effects of Natural Biflavones from Ginkgo against Human CYP1B1 in Recombinant Enzymes and MCF-7 Cells

Human cytochrome P450 1B1 (CYP1B1) is an extrahepatic enzyme overexpressed in many tumors and associated with angiogenesis. Ginkgetin, isoginkgetin, sciadopitysin, and amentoflavone, the primary biflavones found in Ginkgo biloba, have excellent anti-inflammatory and anti-tumor effects. However, the effect of biflavones on CYP1B1 activities remains unknown. In this study, 7-ethoxyresorufin O-deethylation (EROD) was used to characterize the activities of CYP1 families. The impacts of four ginkgo biflavones on CYP1B1 activity and the cellular protein expression of CYP1B1 were systematically investigated. The results showed that amentoflavone with six hydroxyl substituents exhibited the most potent selective inhibitory effect on CYP1B1 activity with IC₅₀ of 0.054 µM in four biflavones. Sciadopitysin, with three hydroxyl and three methoxy substituents, had the weakest inhibitory activity against CYP1B1. Ginkgetin and isoginkgetin, both with four hydroxyl and two methoxy substituents, showed similar inhibitory intensity towards CYP1B1 with IC₅₀ values of 0.289 and 0.211 µM, respectively. Kinetic analysis showed that ginkgetin and amentoflavone inhibited CYP1B1 in a non-competitive mode, whereas sciadopitysin and isoginkgetin induced competitive or mixed types of inhibition. Notably, four ginkgo biflavones were also confirmed to suppress the protein expressions of CYP1B1 and AhR in MCF-7. Furthermore, molecular docking studies indicated more hydrogen bonds formed between amentoflavone and CYP1B1, which might explain the strongest inhibitory action towards CYP1B1. In summary, these findings suggested that biflavones remarkably inhibited both the activity and protein expression of CYP1B1 and the inhibitory activities enhanced with the increasing hydroxyl substitution, providing new insights into the anti-tumor potentials of biflavones.

Modulation of Bleomycin-induced Oxidative Stress and Pulmonary Fibrosis by Ginkgetin in Mice via AMPK

BACKGROUND

Ginkgetin, a flavonoid extracted from Ginkgo biloba, has been shown to exhibit broad anti-inflammatory, anticancer, and antioxidative bioactivity. Moreover, the extract of Ginkgo folium has been reported on attenuating bleomycin-induced pulmonary fibrosis, but the anti-fibrotic effects of ginkgetin are still unclear. This study was intended to investigate the protective effects of ginkgetin against experimental pulmonary fibrosis and its underlying mechanism.

METHODS

In vivo, bleomycin (5 mg/kg) in 50 μL saline was administrated intratracheally in mice. One week after bleomycin administration, ginkgetin (25 or 50 mg/kg) or nintedanib (40 mg/kg) was administrated intragastrically daily for 14 consecutive days. In vitro, the AMPK-siRNA transfection in primary lung fibroblasts further verified the regulatory effect of ginkgetin on AMPK.

RESULTS

Administration of bleomycin caused characteristic histopathology structural changes with elevated lipid peroxidation, pulmonary fibrosis indexes, and inflammatory mediators. The bleomycin- induced alteration was normalized by ginkgetin intervention. Moreover, this protective effect of ginkgetin (20 mg/kg) was equivalent to that of nintedanib (40 mg/kg). AMPK-siRNA transfection in primary lung fibroblasts markedly blocked TGF-β1-induced myofibroblasts transdifferentiation and abolished oxidative stress.

CONCLUSION

All these results suggested that ginkgetin exerted ameliorative effects on bleomycininduced oxidative stress and lung fibrosis mainly through an AMPK-dependent manner.

Potential roles and molecular mechanisms of phytochemicals against cancer

Increasing evidence has been reported regarding phytochemicals, plant secondary metabolites, having therapeutic functions against numerous human diseases. Recently, phytochemicals (flavonoids, polyphenols, terpenoids, alkaloids, saponins, coumarins and so on) have shown promising anti-cancer efficacy with their distinct advantages of high efficiency and low toxicity. They regulate programmed cell death (apoptosis, pyroptosis, and autophagy), migration and senescence-related signaling pathways of cancer via the modulation of reactive oxygen species (ROS), mitogen activated protein kinase (MAPK) pathway, deleted in liver cancer 1 (DLC1), nuclear factor κ light-chain-enhancer of activated B cell (NF-κB) pathways and glycolytic enzymes. Here, we review the molecular mechanisms by which phytochemicals prevent the development of cancer. Furthermore, phytochemicals combined with chemotherapeutic agents could target the crosstalk among multiple signal cascades to block chemoresistance and attenuate carcinogenic properties, and can be considered as a novel and potential therapeutic strategy. Our review highlights that the mechanisms and promising applications are required to be understood to decisively establish the anti-cancer efficacy of natural phytochemicals.

Cytotoxic effects of the biflavonoids isolated from Selaginella trichoclada on MCF-7 cells and its potential mechanism

A new biflavonoid, (2''S)-6''-methyl-2'',3''-dihydroochnaflavone (1), along with two known ochnaflavones (2, 3), four known amentoflavones (4-7) and two known robustaflavones (8, 9) were obtained from the 70% EtOH extract of Selaginella trichoclada. The chemical structures of isolated compounds were elucidated by extensive spectroscopic analyses. Overall, compounds 1-9 displayed moderate cytotoxic effects against human breast cancer MCF-7 cell lines. Among them, compounds 2 and 8 exhibited relatively strong cytotoxic effects against MCF-7 cells with an IC₅₀ value of 7.7 and 6.9 μΜ, respectively. The results of RNA-sequencing and KEGG functional enrichment analysis showed that 8 could induce ferroptosis in MCF-7 cells by down-regulating the expression of ferroptosis-related genes including ACSL4, NOXO1, NOXA1, ACSL5, STEAP3, LPCAT3, ATG7 and TP53. Then 8 could inhibit the expression of ACSL4 proteins through molecule docking analysis, which showed a strong interaction of - 11.89 Kcal/mol binding energy. Those results indicate that 8 could be chemotherapy agents to fight drug resistance in breast cancer by down-regulating the expression level of ACSL4 proteins via ferroptosis, which needs to be further certified in vitro.

Wharton jelly stem cells inhibits AGS gastric cancer cells through induction of apoptosis and modification of MAPK and NF-κB signaling pathways

BACKGROUND

Gastric cancer) GC) is one of the most common cancer with high mortality worldwide. The human Wharton's jelly stem cells (hWJSCs) can inhibit several cancer cells through several molecular pathways. Therefore, the present study aimed to investigate anticancer effects of hWJSCs conditioned medium (hWJSC-CM) and cell-free lysate (hWJSC-CL) against of GC cell line AGS and underlying signaling pathways.

METHODS

In this study, we evaluated the effects of hWJSC-CM and hWJSC-CL on viability, proliferation, migration, invasion, apoptosis, and MAPK and NF-κB signaling pathways in AGS cells. Moreover, mRNA expression of genes involved in apoptosis (BAX, BCL2, SMAC, and SURVIVIN), as well as expression of proteins involved in NF-κB and MAPK signaling pathways were evaluated.

RESULTS

The obtained results showed that the hWJSC-CM and hWJSC-CL decreased viability, migration, and invasion of GC cell line AGS in a concentration and time dependent manner. We observed that the hWJSC-CM and hWJSC-CL induced apoptosis pathway through regulation of apoptosis involved genes mRNA expression. In addition, the hWJSC-CM and hWJSC-CL suppressed NF-κB signaling pathways as well as promoted MAPK signaling pathways.

CONCLUSION

In general, our study suggested that the hWJSC-CM and hWJSC-CL inhibits proliferation and viability of GC cell line AGS through induction of apoptosis, as well as modification of NF-κB and MAPK signaling pathways.

A Brief Updated Review of Advances to Enhance Resveratrol's Bioavailability

Resveratrol (RES) has a low bioavailability. This limitation was addressed in an earlier review and several recommendations were offered. A literature search was conducted in order to determine the extent of the research that was conducted in line with these recommendations, along with new developments in this field. Most of the identified studies were pre-clinical and confirmed the heightened activity of RES analogues compared to their parent compound. Although this has provided additional scientific kudos for these compounds and has strengthened their potential to be developed into phytopharmaceutical products, clinical trials designed to confirm this increased activity remain lacking and are warranted.

Ginkgetin derived from Ginkgo biloba leaves enhances the therapeutic effect of cisplatin via ferroptosis-mediated disruption of the Nrf2/HO-1 axis in EGFR wild-type non-small-cell lung cancer

BACKGROUND

Cisplatin (DDP) is the first-in-class drug for advanced and non-targetable non-small-cell lung cancer (NSCLC). A recent study indicated that DDP could slightly induce non-apoptotic cell death ferroptosis, and the cytotoxicity was promoted by ferroptosis inducer. The agents enhancing the ferroptosis may therefore increase the anticancer effect of DDP. Several lines of evidence supporting the use of phytochemicals in NSCLC therapy. Ginkgetin, a bioflavonoid derived from Ginkgo biloba leaves, showed anticancer effects on NSCLC by triggering autophagy. Ferroptosis can be triggered by autophagy, which regulates redox homeostasis. Thus, we aimed to elucidate the possible role of ferroptosis involved in the synergistic effect of ginkgetin and DDP in cancer therapy.

METHODS

The promotion of DDP-induced anticancer effects by ginkgetin was examined via a cytotoxicity assay and western blot. Ferroptosis triggered by ginkgetin in DDP-treated NSCLC was observed via a lipid peroxidation assay, a labile iron pool assay, western blot, and qPCR. With ferroptosis blocking, the contribution of ferroptosis to ginkgetin + DDP-induced cytotoxicity, the Nrf2/HO-1 axis, and apoptosis were determined via a luciferase assay, immunostaining, chromatin immunoprecipitation (CHIP), and flow cytometry. The role of ferroptosis in ginkgetin + DDP-treated NSCLC cells was illustrated by the application of ferroptosis inhibitors, which was further demonstrated in a xenograft nude mouse model.

RESULTS

Ginkgetin synergized with DDP to increase cytotoxicity in NSCLC cells, which was concomitant with increased labile iron pool and lipid peroxidation. Both these processes were key characteristics of ferroptosis. The induction of ferroptosis mediated by ginkgetin was further confirmed by the decreased expression of SLC7A11 and GPX4, and a decreased GSH/GSSG ratio. Simultaneously, ginkgetin disrupted redox hemostasis in DDP-treated cells, as demonstrated by the enhanced ROS formation and inactivation of the Nrf2/HO-1 axis. Ginkgetin also enhanced DDP-induced mitochondrial membrane potential (MMP) loss and apoptosis in cultured NSCLC cells. Furthermore, blocking ferroptosis reversed the ginkgetin-induced inactivation of Nrf2/HO-1 as well as the elevation of ROS formation, MMP loss, and apoptosis in DDP-treated NSCLC cells.

CONCLUSION

This study is the first to report that ginkgetin derived from Ginkgo biloba leaves promotes DDP-induced anticancer effects, which can be due to the induction of ferroptosis.

Potential hepatic and renal toxicity induced by the biflavonoids from Ginkgo biloba

Evidence continues to grow on potential health risks associated with Ginkgo biloba and its constituents. While biflavonoid is a subclass of the flavonoid family in Ginkgo biloba with a plenty of pharmacological properties, the potential toxicological effects of biflavonoids remains largely unknown. Thus, the aim of this study was to investigate the in vitro and in vivo toxicological effects of the biflavonoids from Ginkgo biloba (i.e., amentoflavone, sciadopitysin, ginkgetin, isoginkgetin, and bilobetin). In the in vitro cytotoxicity test, the five biflavonoids all reduced cell viability in a dose-dependent manner in human renal tubular epithelial cells (HK-2) and human normal hepatocytes (L-02), indicating they might have potential liver and kidney toxicity. In the in vivo experiments, after intragastrical administration of these biflavonoids at 20 mg·kg^-1·d^-1 for 7 days, serum biochemical analysis and histopathological examinations were performed. The activity of alkaline phosphatase was significantly increased after all the biflavonoid administrations and widespread hydropic degeneration of hepatocytes was observed in ginkgetin or bilobetin-treated mice. Moreover, the five biflavonoids all induced acute kidney injury in treated mice and the main pathological lesions were confirmed to the tubule, glomeruli, and interstitium injuries. As the in vitro and in vivo results suggested that these biflavonoids may be more toxic to the kidney than the liver, we further detected the mechanism of biflavonoids-induced nephrotoxicity. The increased TUNEL-positive cells were detected in kidney tissues of biflavonoids-treated mice, accompanied by elevated expression of proapoptotic protein BAX and unchanged levels of antiapoptotic protein BCL-2, indicating apoptosis was involved in biflavonoids-induced nephrotoxicity. Taken together, our results suggested that the five biflavonoids from Ginkgo biloba may have potential hepatic and renal toxicity and more attentions should be paid to ensure Ginkgo biloba preparations safety.

The apatinib inhibits breast cancer cell line MDA-MB-231 in vitro by inducing apoptosis, cell cycle arrest, and regulating nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways

BACKGROUND AND PURPOSE

Breast cancer is one of the most common cancers and leading causes of death in the women worldwide. The evidence shows efficacy of apatinib against breast cancer. Accordingly, the present study was conducted to investigate the effect of apatinib on apoptosis, cell cycle, and Mitogen‑Activated Protein Kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways in the breast cancer MDA-MB-231 cell line.

METHODS

The effects of apatinib on viability, morphology, tumor spheroid, cell cycle, migration, invasion, and apoptosis of MDA-MB-231 breast cancer cells were evaluated in vitro. In addition, expression of proteins involved in NF-κB and MAPK signaling pathways was evaluated using the western blotting analysis.

RESULTS

Apatinib decreased viability, tumor spheroid, migration, and invasion of MDA-MB-231 cells. Furthermore, apatinib altered morphology and regulated cell cycle which followed by apoptosis induction in MDA-MB-231 cells. Apatinib decreased expression of p-p65 and p65 proteins in NF-κB signaling pathways and increased expression of p38, p-p38, JNK, and p-JNK in MAPK signaling pathways.

CONCLUSION

The results suggested that apatinib can inhibit proliferation, migration and invasion of breast cancer cell line MDA-MB-231 through inducing apoptosis, cell cycle arrest, and regulating NF-κB and MAPK signaling pathways.

Synergy of Ginkgetin and Resveratrol in Suppressing VEGF-Induced Angiogenesis: A Therapy in Treating Colorectal Cancer

Ginkgetin, a biflavone from Ginkgo biloba leaf, and resveratrol, a polyphenol found in grape and wine, are two phytochemicals being identified for its binding to vascular endothelial growth factor (VEGF): the binding, therefore, resulted in the alteration of the physiological roles of VEGF-mediated angiogenesis. The bindings of ginkgetin and resveratrol were proposed on different sites of VEGF, but both of them suppressed the angiogenic properties of VEGF. The suppressive activities of ginkgetin and resveratrol in VEGF-mediated angiogenesis were supported by several lines of evidence including (i) inhibiting the formation of sub-intestinal vessel in zebrafish embryos and microvascular sprouting in rat aortic ring; and (ii) suppressing the phosphorylations of VEGFR2, Akt, eNOS, and Erk as well as expressions of matrix metalloproteinases (MMPs), MMP-2, and MMP-9 in human umbilical vein endothelial cells (HUVECs). Here, we showed the synergy of ginkgetin and resveratrol in suppressing the VEGF-induced endothelial cell proliferation, migration, invasion, and tube formation. The synergy of ginkgetin and resveratrol was further illustrated in HT-29 colon cancer xenograft nude mice. Ginkgetin and resveratrol, when applied together, exerted a synergistic anti-tumor effect of 5-fluorouracil with decreasing microvessel density of tumors. In parallel, the combination of ginkgetin and resveratrol synergistically relieved the 5-fluorouracil-induced inflammatory response by suppressing expressions of COX-2 and inflammatory cytokines. Thus, the anti-angiogenic roles of ginkgetin and/or resveratrol could provide effective therapeutic strategy in cancer, similar to that of Avastin, in suppressing the VEGF-mediated angiogenesis during cancer development.

Ginkgetin in vitro and in vivo reduces Streptococcus suis virulence by inhibiting suilysin activity

AIMS

Suilysin (SLY), a crucial virulence-related factor, has multiple cytotoxicities that are regarded as playing a key role in several diseases induced by Streptococcus suis. The aim of this study was to identify an effective inhibitor of SLY and to evaluate the potential inhibitory effect of the inhibitor against S. suis virulence.

METHODS AND RESULTS

Antibacterial activity experiments and haemolysis tests were used to identify the SLY inhibitor ginkgetin, and Western blot analysis and oligomerization inhibition tests were employed to determine the potential mechanism for its inhibition effect. The potential inhibitory effect of ginkgetin against S. suis virulence was then assessed through a cytotoxicity test and a mouse infection model. In this study, we demonstrated that the natural ingredient ginkgetin can significantly reduce the haemolytic activity of SLY to protect against S. suis-mediated cell injury in vitro by directly binding to SLY to block the oligomerization of the protein and reducing the bacterial burden in vivo.

CONCLUSIONS

The results suggest that ginkgetin can start being used as a potential lead drug for the treatment of S. suis infections.

SIGNIFICANCE AND IMPACT OF THE STUDY

The prevention and treatment of S. suis infection might be possible through the targeting of SLY by ginkgetin.

Aromatase (CYP19) inhibition by biflavonoids obtained from the branches of Garcinia gardneriana (Clusiaceae)

Overexpression of aromatase in breast cancer cells may substantially influence its progression and maintenance. In this sense, the inhibition of aromatase is a key target for the treatment of breast cancer in postmenopausal women. Although several flavonoids had already demonstrated the capacity of inhibiting aromatase activity, the role of biflavonoids as aromatase inhibitors is poorly studied. In this work, the biflavonoids isolated from Garcinia gardneriana, morelloflavone (1), Gb-2a (2) and Gb-2a-7-O-glucose (3) were submitted to in vitro assay to evaluate the aromatase modulatory effect. As results, it was demonstrated that all biflavonoids were able to inhibit the enzyme, with IC50 values ranging from 1.35 to 7.67 μM. This demonstrates that biflavonoids are an important source of scaffolds for the development of new aromatase inhibitors, focusing on the development of new anticancer agents.

Neuroprotective effect of ginkgetin in experimental cerebral ischemia/reperfusion via apoptosis inhibition and PI3K/Akt/mTOR signaling pathway activation

BACKGROUND

Ginkgetin, extracted from Ginkgo biloba L leaves, has been demonstrated to have potential anti-inflammatory and immune-suppressive properties. But the neuroprotective effect and potential mechanisms of ginkgetin on cerebral ischemia/reperfusion (IR) injury remain unclear.

METHODS

In this research, we studied the neuroprotective effect of ginkgetin in the middle part of the middle cerebral artery occlusion/reperfusion rat model, by analyzing the apoptosis of brain tissues harvested from treatment groups and control groups using the terminal deoxynucleotidyl transferase dUTP nick-end labeling and apoptosis assays. In addition, we detected the association of the neuroprotective effect of ginkgetin with apoptosis inhibition via the activation of the phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway using Western blot analysis.

RESULTS

Our results showed that administration of ginkgetin remarkably reduced brain infarction volumes and neurologic deficits; in addition, reducing apoptotic cell numbers, downregulating the levels of cleaved caspase-3 and Bax, and upregulating the level of Bcl-2 in rats subjected to IR injury in a dose-dependent manner. Moreover, high-dose ginkgetin treatment (100 mg/kg) significantly increased the phosphorylations of Akt and mTOR. Blocking of PI3K by LY294002 clearly decreased its antiapoptotic effect and reduced both Akt and mTOR phosphorylation levels.

CONCLUSIONS

Taken together, these results for the first time suggest that ginkgetin antagonizes cerebral IR-induced injury by inhibiting apoptosis in rats, and this effect was attenuated by the activation of PI3K/Akt/mTOR signaling pathway.

A Novel Peptide from Abalone (Haliotis discus hannai) to Suppress Metastasis and Vasculogenic Mimicry of Tumor Cells and Enhance Anti-Tumor Effect In Vitro

Vasculogenic mimicry (VM) formed by tumor cells plays a vital role in the progress of tumor, because it provides nutrition for tumor cells and takes away the metabolites. Therefore, the inhibition of VM is crucial to the clinical treatment of tumors. In this study, we investigated the anti-tumor effect of a novel peptide, KVEPQDPSEW (AATP), isolated from abalone (Haliotis discus hannai) on HT1080 cells by migration, invasion analysis and the mode of action. The results showed that AATP effectively inhibited MMPs by blocking MAPKs and NF-κB pathways, leading to the downregulation of metastasis of tumor cells. Moreover, AATP significantly inhibited VM and pro-angiogenic factors, including VEGF and MMPs by suppression of AKT/mTOR signaling. In addition, molecular docking was used to study the interaction of AATP and HIF-1α, and the results showed that AATP was combined with an active site of HIF-1α by a hydrogen bond. The effect of AATP on anti-metastatic and anti-vascular in HT1080 cells revealed that AATP may be a potential lead compound for treatment of tumors in the future.

Licochalcone A Inhibits Cellular Motility by Suppressing E-cadherin and MAPK Signaling in Breast Cancer

A compound isolated from Glycyrrhiza uralensis, licochalcone A (LA) exhibits anti-inflammatory and anti-tumor properties in various cell lines. LA has been found to promote autophagy and suppress specificity protein 1, inducing apoptosis in breast cancer cells. However, the regulation of breast cancer cell invasion and migration by LA is elusive. Thus, the present study investigated whether LA induces apoptosis and cellular motility in MDA-MB-231 breast cells, and investigated the underlying molecular mechanisms. MDA-MB-231 cells treated with LA and cell viability measured by cell counting kit-8 assay. Apoptotic signal proteins checked by flow cytometry, fluorescent staining, and Western blot. LA effectively suppressed cell migration, and modulated E-cadherin and vimentin expression by blocking MAPK and AKT signaling. LA inhibited cell proliferation and cell cycle, modulated mitochondrial membrane potential and DNA damage, and reduced oxidative stress in MDA-MB-231 cells. LA also activated cleaved-caspase 3 and 9, significantly decreased Bcl-2 expression, ultimately causing the release of cytochrome c from the mitochondria into the cytoplasm. Overall, our findings suggest that LA decreases cell proliferation and increases reactive oxygen species production for induced apoptosis, and regulates E-cadherin and vimentin by reducing MAPK and AKT signaling, resulting in suppressed MDA-MB-231 cell migration and invasion.

Coupling Ultrasound with Heat-Reflux to Improve the Extraction of Quercetin, Kaempferol, Ginkgetin and Sciadopitysin from Mairei Yew Leaves

The coupling of ultrasound and heat–reflux extraction (UHRE) was developed for separation for quercetin (QU), kaempferol (KA), ginkgetin (GI) and sciadopitysin (SC) from Mairei Yew leaves. The Box–Behnken design was used to optimize the UHRE conditions for obtaining the maximum yield of flavonoids. The optimal extraction conditions were as follows: boiling 80% methanol (V/V) for extraction solvent, 20 min for the extraction time, 200 W for the ultrasonic power and 26 mL/g for the liquid–solid ratio. By UHRE, the yields of QU, KA, GI and SC were, respectively, 0.109, 0.406, 0.031 and 0.355 mg/g, and total yield of four flavonoids was 0.901 mg/g, which were, respectively, 1.25-fold and 1.23-fold higher than those by using ultrasonic-assisted extraction (UAE) and heating reflux extraction (HRE). Moreover, the extraction time for the equilibrium yields of flavonoids using UHRE was 83.3% and 27.8%, respectively, less than the corresponding time using UAE and HRE. Compared with HRE and UAE, UHRE showed the increase of cell disruption degree as observed by scanning electron microscopy, which may be the reason for high yield and rapid extraction of target compounds.

[Aloin induces apoptosis via regulating the activation of MAPKs signaling pathway in human gastric cancer cells in vitro]

OBJECTIVE

To investigate the effect of aloin on apoptosis of human gastric cancer cells and explore the molecular mechanism.

METHODS

Gastric cancer MKN-28 and HGC-27 cells were cultured routinely in 1640 medium supplemented with 10% fetal bovine serum and 10% non-essential amino acids (for HGC-27 cells) and treated with different concentrations of aloin for different durations. The cell viability, cell nuclear morphology, and apoptotic rate of the cells were detected using CCK-8 assay, DAPI staining and AnnexinV-FITC/PI, respectively; Western blotting was used to detect the expression levels of PARP, procaspase 3 and the phosphorylation of p38, ERK and JNK. The cells were treated with specific inhibitors of p38, ERK and JNK, and the inhibitory effects on these pathways were detected with Western blotting; DAPI staining was used to detect the effects of inhibitors on apoptosis of gastric cancer cells.

RESULTS

Aloin dose-dependently inhibited the viability and induced apoptosis of HGC-27 and MKN-28 cells. Alion treatment obvious enhanced the phosphorylation of p38 and JNK but decreased ERK phosphorylation in the cells. Blocking ERK activation with the ERK inhibitor obviously enhanced aloin-induced cell apoptosis, where inhibiting p38 and JNK activation partly reversed alion-induced apoptosis in the cells.

CONCLUSIONS

Aloin induces apoptosis of human gastric cancer cells in vitro by activating p38 and JNK signaling pathways and inhibiting ERK signaling pathway.

The Research Progress of Chalcone Isomerase (CHI) in Plants

Chalcone isomerase (CHI) is the second rate-limiting and the first reported enzyme involved in the biosynthetic pathway of flavonoids. It catalyzes the intramolecular cyclization reaction, converting the bicyclic chalcone into tricyclic (2S)-flavanone. In this paper, we obtained and analyzed 916 DNA sequences, 1310 mRNA sequences, and 2403 amino acid sequences of CHI registered in NCBI by Jan 2018. The full length of CHI DNA sequences ranges from 218 to 3758 bp, CHI mRNA sequences ranges from 265 to 1436 bp, and CHI amino acid sequences ranges from 35 to 465 amino acid residues. Forty representative species were selected from each family to construct the maximum likelihood tree and analyze the evolutionary relationship. According to the medicinal and agricultural use, 13 specific species were selected, and their physicochemical properties were analyzed. The molecular weight of CHI ranges from 23 to 26 kD, and the isoelectric point of CHI ranges from 4.93 to 5.85. All the half-life periods of CHI are 30 h in mammalian reticulocytes in vitro, 20 h in yeast, and 10 h in E. coli in vivo, theoretically. The consistency of the 13 CHI amino acid sequences is 63.55%. According to the similarity between each sequence, we selected four CHI sequences of Paeonia suffruticosa, Paeonia lactiflora, Taxus wallichiana, and Tradescantia hirsutiflora for secondary structure, three-dimensional protein models, conserved domains, transmembrane structure, and signal peptide prediction analysis. It was found that CHI sequences of Paeonia suffruticosa and Paeonia lactiflora owned a higher similarity; they both share the template 4doi.1.A. The four CHI all have no signal peptides, and they exert their activities in cytoplasm. Then, PubMed, Web of Science, Science Direct, and Research Gate were used as information sources through the search terms 'chalcone isomerase', 'biosynthesis', 'expression', and their combinations to get the latest and comprehensive information of CHI, mainly from the year 2010 to 2018. More than 300 papers were searched and 116 papers were reviewed in the present work. We summarized the classification of CHI, catalytic reaction mechanism of CHI, and progress of genetic engineering regarding CHI clone, expression, and exogenous stimulator regulation. This paper will lay a foundation for further studies of CHI and other functional genes involved in flavonoids biosynthetic pathway.

Nobiletin inhibits breast cancer via p38 mitogen-activated protein kinase, nuclear transcription factor-κB, and nuclear factor erythroid 2-related factor 2 pathways in MCF-7 cells

INTRODUCTION

Breast cancer is one of the most commonly diagnosed cancers in women, with a high mortality rate.

OBJECTIVE

In the present study, we evaluated the anticancer effect of nobiletin, a flavone glycoside, on the breast cancer cell line MCF-7.

RESULT

Cell viability and proliferation decreased and cell morphology changed from diamond to round after being treated with nobiletin. Nobiletin induced apoptosis of breast cancer MCF-7 cells via regulating the protein expression of Bax, Bcl-2, cleaved caspase-3, and p53. The expression of Bcl-2 decreased, while the expression of Bax and p53 increased in MCF-7 cells treated with nobiletin. Meanwhile, nobiletin inhibited cell migration by downregulating the protein expression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). Moreover, phosphorylation of p38 was increased, and the translocation of p65 and nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus was decreased, which suggested that the anticancer effects of nobiletin might at least partially rely on mediating the p38 mitogen-activated protein kinase, nuclear transcription factor-κB, and Nrf2 pathways in MCF-7 breast cancer cells.

CONCLUSION AND RECOMMENDATION

Our data showed that nobiletin was a potential antitumor drug, and it provided some experimental basis for the clinical application of tumor therapy.

Inducible HSP70 antagonizes cisplatin‑induced cell apoptosis through inhibition of the MAPK signaling pathway in HGC‑27 cells

Inducible heat shock protein 70 (HSP70; also known as HSPA1 or HSP72) is implicated in cancer. As a stress-inducible heat shock protein, HSP70 is highly expressed in a variety of cancers and correlates with metastasis, chemotherapy resistance and tumor prognosis. The present study demonstrated that suppression of HSP70 through the specific inhibitor pifithrin-µ or by HSP70 knockdown enhanced cisplatin-induced apoptosis in HGC-27 gastric cancer cells. By contrast, upregulation of HSP70 through transfection of a HSP70 overexpressing plasmid decreased cisplatin-induced HGC-27 cell apoptosis. In exploring the underlying molecular mechanisms, the present results revealed that HSP70 antagonized cisplatin-induced HGC-27 cell apoptosis by regulating the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, suppressing the MAPK pathway enhanced cisplatin-induced HGC-27 cell apoptosis. Collectively, the present findings suggest that inhibition of HSP70 expression enhanced the sensitivity of HGC-27 cells to cisplatin via the MAPK signaling pathway, and that HSP70 may serve as a potential therapeutic target in gastric cancer.