Oridonin inhibits tumor growth and metastasis through anti-angiogenesis by blocking the Notch signaling

Oridonin from Rabdosia rubescens: An emerging potential in cancer therapy - A comprehensive review

Cancer incidences are rising each year. In 2020, approximately 20 million new cancer cases and 10 million cancer-related deaths were recorded. The World Health Organization (WHO) predicts that by 2024 the incidence of cancer will increase to 30.2 million individuals annually. Considering the invasive characteristics of its diagnostic procedures and therapeutic methods side effects, scientists are searching for different solutions, including using plant-derived bioactive compounds, that could reduce the probability of cancer occurrence and make its treatment more comfortable. In this regard, oridonin (ORI), an ent-kaurane diterpenoid, naturally found in the leaves of Rabdosia rubescens species, has been found to have antitumor, antiangiogenesis, antiasthmatic, antiinflammatory, and apoptosis induction properties. Extensive research has been performed on ORI to find various mechanisms involved in its anticancer activities. This review article provides an overview of ORI's effectiveness on murine and human cancer populations from 1976 to 2022 and provides insight into the future application of ORI in different cancer therapies.

The Natural Product Oridonin as an Anticancer Agent: Current Achievements and Problems

Oridonin, an active diterpenoid isolated from traditional Chinese herbal medicine, has received a rising attention for its remarkable roles in cancer therapy. In recent years, increasing evidences have revealed that oridonin inhibits the occurrence and development of tumor cells through multiple mechanisms, including induction of apoptosis and autophagy, cell cycle arrest, and inhibition of angiogenesis as well as migration and invasion. In addition, several molecular signal targets have been identified, including ROS, EGFR, NF-κB, PI3K/Akt, and MAPK. In this paper, we review considerable knowledge about the molecular mechanisms and signal targets of oridonin, which has been studied in recent years. It is expected that oridonin may be developed as a novel anti-tumor herbal medicine in human cancer treatment.

Characterization of the Dynamic Gastrointestinal Digests of the Preserved Eggs and Their Effect and Mechanism on HepG2 Cells

Preserved eggs, an alkaline-fermented food, have been widely searched for their anti-inflammatory activity. Their digestive characteristics in the human gastrointestinal tract and anti-cancer mechanism have not been well explained. In this study, we investigated the digestive characteristics and anti-tumor mechanisms of preserved eggs using an in vitro dynamic human gastrointestinal-IV (DHGI-IV) model. During digestion, the sample pH dynamically changed from 7.01 to 8.39. The samples were largely emptied in the stomach with a lag time of 45 min after 2 h. Protein and fat were significantly hydrolyzed with 90% and 87% digestibility, respectively. Moreover, preserved eggs digests (PED) significantly increased the free radical scavenging activity of ABTS, DPPH, FRAP and hydroxyl groups by 15, 14, 10 and 8 times more than the control group, respectively. PED significantly inhibited the growth, cloning and migration of HepG2 cells at concentrations of 250-1000 μg/mL. Meanwhile, it induced apoptosis by up/down-regulating the expression of the pro-apoptotic factor Bak and the anti-apoptotic gene Bcl-2 in the mitochondrial pathway. PED (1000 μg/mL) treatment resulted in 55% higher ROS production than the control, which also led to apoptosis. Furthermore, PED down-regulated the expression of the pro-angiogenic genes HIF-1α and VEGF. These findings provided a reliable scientific reference for the study of the anti-tumor activity of preserved eggs.

Anti-angiogenic effects of aqueous extract from Agrostemma githago L. seed in human umbilical vein endothelial cells via regulating Notch/VEGF, MMP2/9, ANG2, and VEGFR2

Abnormal angiogenesis contributes to the pathogenesis of various diseases. The medicinal usage of Agrostemma githago L. seed (A. githago herein) has been stated in traditional medicine. This study aims to investigate the anti-angiogenic potential of aqueous extract of A. githago. In order to test the effect of A. githago extract, its impact on HUVECs, T98G, and HGF2PI2 cells was assessed by looking at cellular viability, changes in the distribution of cells in different phases of the cell cycle, induction of oxidative stress, and apoptosis. In addition, the release of VEGF, ANG2, and MMP2/9 factors, along with the expressions of the critical Notch signaling pathway players and VEGF receptors (VEGFR), was measured. Furthermore, a γ-secretase inhibitor (LY411575) was applied to determine whether Notch inhibition restores A. githago effects. As a further characterization, total phenolic and flavonoid contents of A. githago were estimated, and five triterpene saponin compounds were identified using LC-ESI-MS. In response to A. githago extract, a reduction in total cell viability, along with the induction of ROS and apoptosis, was detected. Exposure to the A. githago extract could modulate the release of VEGF and ANG2 from T98G and HUVECs, respectively. In addition, A. githago reduced the release of MMP2/9. Furthermore, Notch1, DLL4, and HEY2 transcripts and protein expressions were up-regulated, while VEGFR2 was down-regulated in treated HUVEC cells. Treatment with the A. githago extract resulted in a dose-dependent inhibition of AKT phosphorylation. Inhibition of Notch signaling retrieved the viability loss, reduced intracellular ROS, and alleviated the impaired tube formation in A. githago-treated HUVECs. Overall, these data underscore the anti-angiogenic potential of A. githago via inducing apoptosis, modifying the expression levels of VEGF/VEGFR2, and impacting the release of MMP2/9 and ANG2, effects that are most probably modulated through the Notch/VEGF signaling axis.

Targeting cancer signaling pathways by natural products: Exploring promising anti-cancer agents

Cancer is one of the leading causes of death and significantly burdens the healthcare system. Due to its prevalence, there is undoubtedly an unmet need to discover novel anticancer drugs. The use of natural products as anticancer agents is an acceptable therapeutic approach due to accessibility, applicability, and reduced cytotoxicity. Natural products have been an incomparable source of anticancer drugs in the modern era of drug discovery. Along with their derivatives and analogs, natural products play a major role in cancer treatment by modulating the cancer microenvironment and different signaling pathways. These compounds are effective against several signaling pathways, mainly cell death pathways (apoptosis and autophagy) and embryonic developmental pathways (Notch pathway, Wnt pathway, and Hedgehog pathway). The historical record of natural products is strong, but there is a need to investigate the current role of natural products in the discovery and development of cancer drugs and determine the possibility of natural products being an important source of future therapeutic agents. Many target-specific anticancer drugs failed to provide successful results, which accounts for a need to investigate natural products with multi-target characteristics to achieve better outcomes. The potential of natural products to be promising novel compounds for cancer treatment makes them an important area of research. This review explores the significance of natural products in inhibiting the various signaling pathways that serve as drivers of carcinogenesis and thus pave the way for developing and discovering anticancer drugs.

Preventive and therapeutic effect of intraportal oridonin on BALb/c nude mice hemispleen model of colon cancer liver metastasis

Background

This study is to investigate the preventive and therapeutic effect of intraportal oridonin on colorectal cancer liver metastasis (CRCLM).

Methods

The inhibitory effect of oridonin on HT29 cells was determined by CCK-8 and MTT assays. The preventive and therapeutic effect of intraportal oridonin on CRCLM were investigated by establishing BALb/c nude mice hemispleen models of colon cancer liver metastasis. The microscopic characteristics of tumor tissues were observed by hematoxylin-eosin staining, immunohistochemistry and TUNEL staining. On the other hand, liver function enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), were detected to evaluate the hepatotoxicity of intraportal oridonin. The serum levels of tumor markers, including carcinoembryonic antigen (CEA) and α-fetoprotein (AFP), were used to investigate the intervention effect of intraportal oridonin on CRCLM.

Results

Oridonin exerted an inhibitory effect on the proliferation of HT29 cells in vitro. Intraportal oridonin was found to effectively prevent the occurrence and formation of CRCLM, whilst intraportal oridonin can also exert a therapeutic effect on CRCLM. Additionally, liver enzymes testing indicated that intraportal oridonin possesses non-hepatotoxicity, instead can effectively alleviate liver injury caused by tumor. Furthermore, intraportal oridonin was also revealed to decrease the serum levels of AFP and CEA.

Conclusions

Intraportal oridonin can effectively inhibit the formation of liver metastatic tumor and exert a certain degree of preventive and therapeutic effect on CRCLM. These findings indicate intraportal oridonin to be a promising anti-metastasis agent for CRCLM.

Oridonin represses epithelial-mesenchymal transition and angiogenesis of thyroid cancer via downregulating JAK2/STAT3 signaling

Oridonin, a bioactive diterpenoid isolated from Rabdosia rubescens, has been reported to exert anticancer activity in various cancers. However, the molecular mechanism of oridonin in thyroid cancer has not yet been elucidated. In the present study, oridonin was found to significantly inhibit migration and invasion of thyroid cancer TPC-1 and BCPAP cells, as evidenced by wound healing assay, transwell migration assay and Matrigel invasion assay. In addition, oridonin could partially impede epithelial-mesenchymal transition by upregulating E-Cadherin expression and downregulating N-Cadherin and vimentin expressions in a concentration-dependent manner. Accumulating evidence indicated that JAK2 (Janus kinase-2)/STAT3 (Signal Transducer and Activator of Transcription 3) signaling pathway was associated with epithelial-mesenchymal transition. As expected, the protein levels of phosphorylated-JAK2 and phosphorylated-STAT3 were dramatically reduced upon oridonin treatment in thyroid cancer TPC-1 and BCPAP cells. Subsequently, the findings revealed that JAK2 overexpression could weaken the anti-metastatic effect and partially attenuate MET (mesenchymal-to-epithelial transition) by oridonin, while AG490, a JAK2 antagonist, enhanced the above process in thyroid cancer cells. The subsequent results showed that oridonin inhibited angiogenesis and VEGFA expression in thyroid cancer cells by tube formation assay, western blot and ELISA assay. Meanwhile, AG490 could further attenuate oridonin-treated VEGFA protein level. In addition, the in vivo results further confirmed that oridonin inhibited tumorigenicity in thyroid cancer xenograft. In conclusion, the results demonstrated that oridonin repressed metastatic phenotype, angiogenesis and modulated EMT (epithelial-mesenchymal transition) of thyroid cancer cells via the inactivation of JAK2/STAT3 signaling pathway, suggesting that JAK2 may be a novel therapeutic target of oridonin against thyroid cancer.

Selective synergistic anticancer effects of cisplatin and oridonin against human p53-mutant esophageal squamous carcinoma cells

Oridonin (ORI) is known to pose anticancer activity against cancer, which could induce the therapeutic impact of chemotherapy drugs. However, such simple combinations have numerous side effects such as higher toxicity to normal cells and tissues. To enhance the therapeutic effects with minimal side effects, here we used ORI in combination with cisplitin (CIS) against different esophageal squamous cell carcinoma (ESCC) cell lines in vitro, to investigate the synergistic anticancer effects of the two drugs against ESCC. Calcusyn Graphing Software was used to assess the synergistic effect. Apoptosis, wound healing and cell invasion assay were conducted to further confirm the synergistic effects of ORI and CIS. Intracellular glutathione (GSH) and reactive oxygen species assay, immunofluorescence staining and western blot were used to verify the mechanism of synergistic cytotoxicity. ORI and CIS pose selective synergistic effects on ESCC cells with p53 mutations. Moreover, we found that the synergistic effects of these drugs are mediated by GSH/ROS systems, such that intracellular GSH production was inhibited, whereas the ROS generation was induced following ORI and CIS application. In addition, we noted that DNA damage was induced as in response to ORI and CIS treatment. Overall, these results suggest that ORI can synergistically enhance the effect of CIS, and GSH deficiency and p53 mutation, might be biomarkers for the combinational usage of ORI and CIS.

Oridonin inhibits tumor angiogenesis and induces vessel normalization in experimental colon cancer

Purpose: Tumor blood vessels exhibit morphological and functional aberrancies. Its maturity and functionality are closely associated with colon cancer progression and therapeutic efficacy. The direct evidence proving whether oridonin (ORI) has vascular normalization promoting effect from which combination therapies will benefit is still lacking. Methods: We established a subcutaneous xenograft model of human colon cancer. The animals were divided into the Control and ORI-treated groups. Immunohistochemical analysis and TUNEL staining was applied to evaluate the proliferation, apoptosis and angiogenesis. Western blot analysis was employed to characterize the angiogenesis-related factors and JAK2/STAT3 signaling. Then, vascular normalization and macrophage reprogramming were assessed by immunofluorescence analysis. Results: The results showed that ORI obviously reduced tumor growth, diminished the numbers of Ki67⁺ cells and CD31⁺ microvessel density, while increased the numbers of TUNEL⁺ cells. The expression levels of VEGF and bFGF proteins were dramatically down-regulated while the angiostatin and endostatin levels were increased in the ORI-treated group. Moreover, ORI therapy remarkably promoted the pericyte coverage of tumor vessels from days 5 to 10, with the highest pericyte coverage rate occurred at day 7. In the time window of vascular normalization, hypoxia of the tumor microenvironment was improved by ORI, the expression of HIF-1a was downregulated. Moreover, CD206⁺ macrophage cells were diminished in the ORI-treated group. These anticancer effects of ORI maybe partly mediated by suppressing JAK2/STAT3 signaling pathway. Conclusions: These results highlight the potential effect of ORI on anti-angiogenesis and inducing vessel normalization roles of ORI, and probably provide optimum time point for the ORI therapy in conjunction with the chemoradiotherapy or immunotherapy.

An Insight into the Anti-Angiogenic and Anti-Metastatic Effects of Oridonin: Current Knowledge and Future Potential

Cancer is one of the leading causes of death worldwide, with a mortality rate of more than 9 million deaths reported in 2018. Conventional anti-cancer therapy can greatly improve survival however treatment resistance is still a major problem especially in metastatic disease. Targeted anti-cancer therapy is increasingly used with conventional therapy to improve patients' outcomes in advanced and metastatic tumors. However, due to the complexity of cancer biology and metastasis, it is urgent to develop new agents and evaluate the anti-cancer efficacy of available treatments. Many phytochemicals from medicinal plants have been reported to possess anti-cancer properties. One such compound is known as oridonin, a bioactive component of Rabdosia rubescens. Several studies have demonstrated that oridonin inhibits angiogenesis in various types of cancer, including breast, pancreatic, lung, colon and skin cancer. Oridonin's anti-cancer effects are mediated through the modulation of several signaling pathways which include upregulation of oncogenes and pro-angiogenic growth factors. Furthermore, oridonin also inhibits cell migration, invasion and metastasis via suppressing epithelial-to-mesenchymal transition and blocking downstream signaling targets in the cancer metastasis process. This review summarizes the recent applications of oridonin as an anti-angiogenic and anti-metastatic drug both in vitro and in vivo, and its potential mechanisms of action.

Discovery of VEGFR-2 inhibitors exerting significant anticancer activity against CD44+ and CD133+ cancer stem cells (CSCs): Reversal of TGF-β induced epithelial-mesenchymal transition (EMT) in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignancy characterized by neoangiogenesis, which is an augmented production of proangiogenic factors by the tumor and its adjacent infected cells. These dysregulated angiogenic factors are the therapeutic targets in anti-angiogenic drug development. The signaling pathway of vascular endothelial growth factor (VEGF)/VEGFR-2 is crucial for controlling the angiogenic responses in endothelial cells (ECs). In this study, we carried out a rational drug design approach wherein we have identified the novel orally bioavailable compound VS 8 as a potent VEGFR-2 inhibitor, which remarkably suppresses hVEGF and hVEGFR-2 expression in HUVECs and exhibits significant anti-angiogenic effects in CAM assay. Besides, VS 8 significantly induces apoptosis in HCC cell line (Hep G2). Later we examined its effectiveness against CD44+ and CD133+ CSCs. Here, VS 8 was found to be active against CSCs, and adequate for the cessation of the cell cycle at 'G₀/G₁' and 'S' phase in CD44+ and CD133+ CSCs respectively. Factually, transforming growth factor-β (TGF-β) stimulated epithelial-mesenchymal transition (EMT) induces invasion and migration of HCC cells, which results in the metastasis. Therefore, we studied the effect of VS 8 on EMT markers using flow cytometry, which suggested that VS 8 significantly upregulates E-cadherin (epithelial biomarker) and downregulates vimentin (mesenchymal biomarker). Further, VS 8 downregulates the expression of EMT-inducing transcription factors (EMT-TFs), i.e., SNAIL. Altogether, our findings indicate that VS 8 could be a promising drug candidate for cancer therapy.

Oridonin exhibits anti-angiogenic activity in human umbilical vein endothelial cells by inhibiting VEGF-induced VEGFR-2 signaling pathway

Oridonin has been found to be a potential anti-angiogenesis agent. However, its functional targets and the underlying mechanisms are still vague. In vitro studies we found that oridonin not only inhibited VEGF-induced cell proliferation, migration and tube formation but also caused G2/M phase arrest and triggered cellular apoptosis in HUVECs. In mechanistic studies revealed that oridonin exhibited the anti-angiogenic potency, at least in part, through the down-regulation of VEGFR2-mediated FAK/MMPs, mTOR/PI3K/Akt and ERK/p38 signaling pathways which led to reduced invasion, migration, and tube formation in HUVECs. Our results could provide evidence that oridonin exerts strong anti-angiogenesis activities via specifically targeting VEGFR2 and its signaling pathway.

Oridonin inhibits the migration and epithelial-to-mesenchymal transition of small cell lung cancer cells by suppressing FAK-ERK1/2 signalling pathway

Small cell lung cancer (SCLC) is a severe malignant with high morbidity; however, few effective and secure therapeutic strategy is used in current clinical practice. Oridonin is a small molecule from the traditional Chinese herb Rabdosia rubescens. This study mainly aimed to investigate the role of oridonin on inhibiting the process of H1688, a kind of small cell lung cancer cells from human. Oridonin could suppress H1688 cell proliferation and induce their apoptosis in a high dosage treatment (20 μmol/L). Meanwhile, cell migration was suppressed by oridonin (5 and 10 μmol/L) that did not affect cell proliferation and apoptosis. The expression level of E-cadherin was significantly increased, and the expression of vimentin, snail and slug was reduced after administration of oridonin. These expression changes were associated with the suppressed integrin β1, phosphorylation of focal adhesion kinase (FAK) and ERK1/2. In addition, oridonin (5 and 10 mg/kg) inhibited tumour growth in a nude mouse model; however, HE staining revealed a certain degree of cytotoxicity in hepatic tissue after treatment oridonin (10 mg/kg). Furthermore, the concentration of alanine aminotransferase (ALP) was significantly increased and lactate dehydrogenase (LDH) was reduced after oridonin treatment (10 mg/kg). Immunohistochemical analysis further revealed that oridonin increased E-cadherin expression and reduced vimentin and phospho-FAK levels in vivo. These findings indicated that oridonin can inhibit the migration and epithelial-to-mesenchymal transition (EMT) of SCLC cells by suppressing the FAK-ERK1/2 signalling pathway. Thus, oridonin may be a new drug candidate to offer an effect of anti-SCLC with relative safety.

Notch1 in Tumor Microvascular Endothelial Cells and Tumoral miR-34a as Prognostic Markers in Locally Advanced Triple-Negative Breast Cancer

Purpose

Triple-negative breast cancer (TNBC) is associated with poor prognosis with limited treatment options. Angiogenesis is known to be involved in the progression of TNBC, and targeting this pathway results in modest clinical benefits. In this study, we analyzed the role of tumor microvascular endothelial Notch1 (EC Notch1) and tumoral miR-34a as prognostic markers in patients with TNBC.

Methods

The expression of miR-34a was analyzed using archival tumor tissues from 114 patients with TNBC. Simultaneously, archival tumor tissues were also checked for the expression of CD34 and Notch1 by immunostaining. The ratio of Notch1-microvascular density (MVD) to CD34-MVD was defined as EC Notch1. The association between the expression of miR-34a or EC Notch1 and clinicopathological characteristics was analyzed.

Results

In the overall patient population, patients with low expression of EC Notch1 was associated with better overall survival (OS, p = 0.041) than those with high expression of EC Notch1. In lymph node-positive TNBC patients, high levels of miR-34a and low levels of EC Notch1 correlated significantly with higher survival benefits in terms of OS (p = 0.026), disease-free survival (p = 0.009), and metastasis-free survival (p = 0.038) relative to that in other patients. Decreased expression of EC Notch1 and increased expression of miR-34a also showed a survival benefit in locally advanced TNBC.

Conclusion

The fact that miR-34a and EC Notch1 are associated with the angiogenesis suggests that angiogenesis may play a role in the development and progression of TNBC.

Preliminary safety assessment of oridonin in zebrafish

Context: Oridonin, isolated from the leaves of Isodon rubescens (Hemsl.) H.Hara (Lamiaceae), has good antitumor activity. However, its safety in vivo is still unclear. Objective: To investigate the preliminary safety of oridonin in zebrafish. Materials and methods: Embryo, larvae and adult zebrafish (n = 40) were used. Low, medium and high oridonin concentrations (100, 200 and 400 mg/L for embryo; 150, 300 and 600 mg/L for larvae; 200, 400 and 800 mg/L for adult zebrafish) and blank samples were administered. At specific stages of zebrafish development, spontaneous movement, heartbeat, hatching rate, etc., were recorded to assess the developmental effects of oridonin. VEGFA, VEGFR2 and VEGFR3 gene expression were also examined. Results: Low-dose oridonin increased spontaneous movement and hatching rate with median effective doses (ED₅₀) of 115.17 mg/L at 24 h post-fertilization (hpf) and 188.59 mg/L at 54 hpf, but these values decreased at high doses with half maximal inhibitory concentrations (IC₅₀) of 209.11 and 607.84 mg/L. Oridonin decreased heartbeat with IC₅₀ of 285.76 mg/L at 48 hpf, and induced malformation at 120 hpf with half maximal effective concentration (EC₅₀) of 411.94 mg/L. Oridonin also decreased body length with IC₅₀ of 324.78 mg/L at 144 hpf, and increased swimming speed with ED₅₀ of 190.98 mg/L at 120 hpf. The effects of oridonin on zebrafish embryo development may be attributed to the downregulation of VEGFR3 gene expression. Discussions and conclusions: Oridonin showed adverse effects at early stages of zebrafish development. We will perform additional studies on mechanism of oridonin based on VEGFR3.

AGS-30, an andrographolide derivative, suppresses tumor angiogenesis and growth in vitro and in vivo

Poor bioavailability and limited efficacy are challenges associated with using andrographolide as a therapeutic agent. We recently synthesized AGS-30, a new andrographolide derivative, in our laboratory. In this study we investigated the potential anti-tumor effect of AGS-30 and the underlying mechanisms, particularly those related to angiogenesis. Results from our in vitro experiments showed that AGS-30 exerted anti-angiogenic effects by inhibiting endothelial cell proliferation, migration, invasion, and tube formation. Phosphorylation and activation of angiogenesis-related signaling molecules (e.g., vascular endothelial growth factor [VEGF] receptor 2, mitogen-activated protein kinase kinase 1/2, extracellular signal-regulated kinase 1/2, mechanistic target of rapamycin [mTOR], protein kinase B [Akt], and p38) were markedly reduced by AGS-30. Meanwhile, AGS-30 potently inhibited cell proliferation and phosphorylation of cell survival-related proteins (e.g., Akt, mTOR, and ERK1/2) and decreased the expression of VEGF in HT-29 colon cancer cells. AGS-30 blocked microvessel sprouting in a rat aortic ring model and blood vessel formation in zebrafish embryos and a mouse Matrigel plug model. Additionally, AGS-30 suppressed tumor growth and angiogenesis in HT-29 colon cancer cell xenografts in nude mice. These effects were not observed when same concentration of andrographolide, the parent compound of AGS-30, was used. Thus, AGS-30 exerted a strong antitumor effect by inhibiting tumor cell growth and angiogenesis and is a candidate compound for the treatment of cancer.

Delivery of Oridonin and Methotrexate via PEGylated Graphene Oxide

Graphene oxide (GO) possessing plenty of hydroxyls and carboxyls is often used in the field of biomedicine. To improve its water solubility and biocompatibility, 6-armed poly(ethylene glycol) (PEG) was bonded on the surface of GO sheets via a facile amidation process to form the universal drug delivery platform (GO-PEG_10K-6arm) with a 200 nm size in favor of the enhanced permeability and retention effect. Herein, we prepared the stable and biocompatible platform of GO-PEG_10K-6arm under mild conditions and characterized the chemical structure and micromorphology via thermogravimetric analysis and atomic force microscopy. This nanosized GO-PEG_10K-6arm was found to be of very low toxicity to human normal cells of 293T and tumor cells of CAL27, MG63, and HepG2. Moreover, oridonin and methotrexate (MTX), widely used hydrophobic cancer chemotherapy drugs, were compounded with GO-PEG_10K-6arm via π-π stacking and hydrophobic interactions so as to afford nanocomplexes of oridonin@GO-PEG_10K-6arm and MTX@GO-PEG_10K-6arm, respectively. Both nanocomplexes could quickly enter into tumor cells, which was evidenced by inverted fluorescence microscopy using fluorescein isothiocyanate as a probe, and they both showed remarkably high cytotoxicity to the tumor cells of CAL27, MG63, and HepG2 within a broad range of concentration in comparison with free drugs. This kind of nanoscale drug delivery system based on GO-PEG_10K-6arm may have potential applications in biomedicine, and GO-PEG_10K-6arm would be a universal and available carrier for extensive hydrophobic anticarcinogens.

Oridonin inhibits metastasis of human ovarian cancer cells by suppressing the mTOR pathway

INTRODUCTION

Oridonin, which is isolated from the Chinese herb Rabdosia rubescens, has been reported to exhibit an anti-tumorous effect on different cancers. In this study, we investigated the molecular mechanism by which oridonin suppresses human ovarian cancer.

MATERIAL AND METHODS

The inhibition of oridonin on cell proliferation was assessed by CCK8 assay. Cell cycle and apoptosis were analyzed by flow cytometry, staining with propidium iodide (PI) or annexin-V/PI respectively. The metastasis rate was evaluated using a transwell migration assay. The expression of metastasis-associated genes and mTOR pathway related genes were detected by western blot.

RESULTS

We demonstrated that oridonin suppressed the proliferation and blocked the cell cycle in G1/S phage and induced apoptosis in SKOV3 and A2780 cells (p < 0.01). We further found that the mTOR signaling pathway was suppressed by the treatment with oridonin, and the activation of the mTOR pathway attenuated the anti-tumorous effect of oridonin in human ovarian cancer cells, suggesting that the mTOR pathway was involved in the anti-tumorous process of oridonin. Additionally, the activation of the mTOR pathway by an exogenous activator reduced the expression level of FOXP3 (p < 0.01), thus providing evidence that FOXP3 is a factor that is necessary for the anti-tumorous effect of oridonin, and is negatively regulated by the mTOR pathway.

CONCLUSIONS

These results suggested that oridonin suppressed the mTOR signaling pathway, up-regulated the FOXP3 level, and inhibited metastasis of human ovarian cancer cells.

Oridonin synergistically enhances the anti-tumor efficacy of doxorubicin against aggressive breast cancer via pro-apoptotic and anti-angiogenic effects

The therapeutic outcomes of doxorubicin (Dox) treatment in breast cancer are limited by decreased drug efficiency and cardiotoxicity. The aim of this study was to investigate whether oridonin (Ori), a natural chemical abundant in the Chinese herb Isodon rubescens, might potentiate the anticancer effects, and decrease the adverse cardiotoxic effects, of Dox. On the basis of the optimized drug ratio determined through combination index calculations, we evaluated the synergistic effects and potential mechanisms of combining Dox with Ori to suppress breast cancer growth and angiogenesis both in vitro and in vivo. Dox plus Ori synergistically induced apoptosis in MDA-MB-231 cells, in a manner involving regulation of the Bcl-2/Bax, PARP, Caspase 3 and Survivin signaling pathways. Additionally, Ori increased the intracellular accumulation of Dox in MDA-MB-231 cells. Moreover, Dox plus Ori significantly decreased the proliferation, migration, invasion and tube formation of HUVECs. The underlying anti-angiogenic mechanism may have been due to the inhibition of VEGFR2-mediated signaling. Computational docking analysis further demonstrated that Dox plus Ori had high affinity toward the ATP-binding domain of VEGFR-2 kinase. Consistently with these findings, in vivo studies indicated that Ori enhanced the antitumor effect of Dox via activating apoptosis and inhibiting blood vessel formation at tumor sites. Moreover, Ori reversed the Dox-induced cardiotoxicity in a mouse model. In conclusion, our findings provide strong evidence that Ori may be highly promising in enhancing the efficacy of Dox and decreasing its adverse cardiotoxic effects, thus suggesting that Ori may serve as a potential adjunct therapy during Dox-based chemotherapy.

Natural Diterpenoid Oridonin Ameliorates Experimental Autoimmune Neuritis by Promoting Anti-inflammatory Macrophages Through Blocking Notch Pathway

The diterpenoid compound, Oridonin, extracted from the Chinese herb, Rabdosia rubescens, possesses multiple biological activities and properties. Oridonin exhibited efficient anti-inflammatory activity by inducing a switch in macrophage polarization to the anti-inflammatory phenotype through inhibition of the Notch pathway in our in vitro study; therefore, its potential therapeutic effects were further investigated in the animal model of human Guillain-Barré syndrome (GBS) and other polyneuropathies - experimental autoimmune neuritis (EAN). Either preventive or therapeutic treatments with Oridonin greatly attenuated disease peak severity, suppressed paraparesis, shortened disease duration, and even delayed EAN onset. Progression of neuropathic pain, demyelination, inflammatory cellular accumulations, and inflammatory cytokines in peripheral nerves were significantly attenuated. Meanwhile, accumulation of immune cells in the spinal roots and microglial activation in the lumbar spinal cord were also reduced. Interestingly, Oridonin treatment significantly increased the proportion of anti-inflammatory macrophages and made them locally dominant among all infiltrated macrophages in the peripheral nerves. The down-regulation of local Notch pathway proteins, together with our in vitro results indicated their possible involvement. Taken together, our results demonstrated that Oridonin effectively suppressed EAN by attenuating local inflammatory reaction and increasing the proportion of immune regulating macrophages in the peripheral nerves, possibly through blockage of the Notch pathway, which suggests Oridonin as a potential therapeutic candidate for human GBS and neuropathies.

Structural modification of oridonin via DAST induced rearrangement

A simple and efficient protocol was developed for the syntheses of oridonin analogues, i.e. 6,20-epoxy ent-kaurane diterpenoid analogues from oridonin via diethylaminosulfur trifluoride (DAST) promoted rearrangement, most of which exhibited superior anticancer activities compared with their precursor.

Oridonin inhibits VEGF-A-associated angiogenesis and epithelial-mesenchymal transition of breast cancer in vitro and in vivo

Metastasis is the primary cause of mortality in patients with breast cancer and lacks effective therapeutic agents. Oridonin, an active diterpenoid compound isolated from Rabdosia rubescens, was identified to be the most potent anti-tumor ingredient. However, the molecular mechanisms responsible for its anti-metastatic effects remain unclear. In the present study, oridonin significantly suppressed the migration, invasion and adhesion of MDA-MB-231 and 4T1 breast cancer cells, and inhibited tube formation of human umbilical vein endothelial cells in a dose-dependent manner. The expression levels of epithelial-mesenchymal transition (EMT)-associated marker and the hypoxia inducible factor 1α (HIF-1α)/vascular endothelium growth factor (VEGF) signaling pathway mRNA and proteins were determined by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively in vitro. The results demonstrated that oridonin effectively inhibited EMT as demonstrated by the significant increases in the expression levels of E-cadherin, and decreased expression of N-cadherin, Vimentin and Snail. In addition, oridonin exerted its anti-angiogenesis activity through significantly decreasing HIF-1α, VEGF-A and VEGF receptor-2 protein expression. Furthermore, oridonin was demonstrated to decrease the micro-vessel density as evidenced by the decreased expression of cluster of differentiation 31, a marker for neovasculature. In brief, oridonin inhibits tumor cell migration, invasion and adhesion, as well as tumor angiogenesis, which are mediated by suppressing EMT and the HIF-1α/VEGF signaling pathway. The results of the present study suggest that oridonin may be a promising anti-metastatic agent in breast cancer treatment.

Carbon nanotubes in the delivery of anticancer herbal drugs

Cancer is estimated to be a significant health problem of the 21st century. The situation gets even tougher when it comes to its treatment using chemotherapy employing synthetic anticancer molecules with numerous side effects. Recently, there has been a paradigm shift toward the adoption of herbal drugs for the treatment of cancer. In this context, a suitable delivery system is principally warranted to deliver these herbal biomolecules specifically at the tumorous site. To achieve this goal, carbon nanotubes (CNTs) have been widely explored to deliver anticancer herbal molecules with improved therapeutic efficacy and safety. This review uniquely expounds the biopharmaceutical, clinical and safety aspects of different anticancer herbal drugs delivered through CNTs with a cross-talk on their outcomes. This review will serve as a one-stop-shop for the readers on various anticancer herbal drugs delivered through CNTs as a futuristic delivery device.

Oridonin protects against the inflammatory response in diabetic nephropathy by inhibiting the TLR4/p38-MAPK and TLR4/NF-κB signaling pathways

Inflammation plays a pivotal role in the development and progression of diabetic nephropathy (DN). Oridonin (Ori), a component isolated from Rabdosia rubescens, possesses remarkable anti-inflammatory, immunoregulatory and antitumor properties. However, the renoprotective effects of Ori and the underlying molecular mechanisms have not been explored in DN. In this study, we aimed to investigate the protective effects and potential mechanisms responsible for the anti-inflammatory effects of Ori in diabetes-induced renal injury in vivo and in vitro. Our results showed that Ori significantly attenuated diabetes-induced renal injury and markedly decreased urinary protein excretion levels, serum creatinine concentrations and blood urea nitrogen concentrations in rats. Ori also significantly alleviated infiltration of inflammatory cells (cluster of differentiation (CD)68) in kidney tissues and reduced the levels of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β and monocyte chemotactic protein 1 (MCP-1), both in vivo and in vitro. TLR4 is a principal mediator of innate immune and inflammatory responses and participates in the development of DN. Our molecular studies indicated that Ori administration significantly down-regulated TLR4 overexpression in DN. Additional studies were conducted to investigate the effect of Ori on the p38-mitogen-activated protein kinase (p38-MAPK) and nuclear factor (NF)-κB pathways. The results showed that Ori inhibited IκBα, p65, and p38 phosphorylation, as well as NF-κB DNA-binding activity. In conclusion, these results demonstrated that Ori exerts protective effects in diabetes-induced renal injury in vivo and in vitro. These effects may be ascribed to its anti-inflammatory and modulatory effects on the TLR4/p38-MAPK and TLR4/NF-κB signaling pathways.

GE11 peptide conjugated selenium nanoparticles for EGFR targeted oridonin delivery to achieve enhanced anticancer efficacy by inhibiting EGFR-mediated PI3K/AKT and Ras/Raf/MEK/ERK pathways

Selenium nanoparticles (Se NPs) have attracted increasing interest in recent decades because of their anticancer, immunoregulation, and drug carrier functions. In this study, GE11 peptide-conjugated Se NPs (GE11-Se NPs), a nanosystem targeting EGFR over-expressed cancer cells, were synthesized for oridonin delivery to achieve enhanced anticancer efficacy. Oridonin loaded and GE11 peptide conjugated Se NPs (GE11-Ori-Se NPs) were found to show enhanced cellular uptake in cancer cells, which resulted in enhanced cancer inhibition against cancer cells and reduced toxicity against normal cells. After accumulation into the lysosomes of cancer cells and increase of oridonin release under acid condition, GE11-Ori-Se NPs were further transported into cytoplasm after the damage of lysosomal membrane integrity. GE11-Ori-Se NPs were found to induce cancer cell apoptosis by inducting reactive oxygen species (ROS) production, activating mitochondria-dependent pathway, inhibiting EGFR-mediated PI3K/AKT and inhibiting Ras/Raf/MEK/ERK pathways. GE11-Se NPs were also found to show active targeting effects against the tumor tissue in esophageal cancer bearing mice. And in nude mice xenograft model, GE11-Ori-Se NPs significantly inhibited the tumor growth via inhibition of tumor angiogenesis by reducing the angiogenesis-marker CD31 and activation of the immune system by enhancing IL-2 and TNF-α production. The selenium contents in mice were found to accumulate into liver, tumor, and kidney, but showed no significant toxicity against liver and kidney. This cancer-targeted design of Se NPs provides a new strategy for synergistic treating of cancer with higher efficacy and reduced side effects, introducing GE11-Ori-Se NPs as a candidate for further evaluation as a chemotherapeutic agent for EGFR over-expressed esophageal cancers.

Synergistic suppression of t(8;21)-positive leukemia cell growth by combining oridonin and MAPK1/ERK2 inhibitors

One of the most common chromosomal translocations in acute myeloid leukemia is t(8;21)(q22;q22), which results in the appearance of abnormal transcripts encoding for the fusion protein RUNX1-ETO. Therefore, this oncoprotein is considered to be a pertinent and promising target for treating t(8;21) leukemia. Previously, we have shown that downregulation of RUNX1-ETO leads to activation of intracellular signaling pathways enhancing cell survival and determined that the protein ERK2 can mediate activation of most of these pathways. Here we used a combination of oridonin (natural tetracycline diterpenoid), which has been shown to exhibit anti-RUNX1-ETO activity, and ERK2 kinase inhibitors. We found that treatment of leukemic t(8;21)-positive Kasumi-1 cells with oridonin cause decrease of phosphorylated ERK1/2. Treatment of these cells with ERK2 inhibitors makes them more sensitive to RUNX1-ETO inhibition with oridonin. Therefore we postulate that simultaneous inhibition of RUNX1-ETO and ERK2 cause synergistic effect on survival of leukemic cells.

Oridonin inhibits breast cancer growth and metastasis through blocking the Notch signaling

Background: Oridonin is a diterpenoid isolated from Rabdosia rubescens with potent anticancer activity. The aim of our study is to investigate the role of oridonin to inhibit growth and metastasis of human breast cancer cells. Methods: The effect of oridonin on proliferation was evaluated by MTT assay, cell migration and invasion were evaluated by transwell migration and invasion assays in human breast cancer cells. The inhibitive effect of oridonin in vivo was determined by using xenografted nude mice. In addition, the expression of Notch receptors (Notch 1–4) was detected by western blot. Results: Oridonin inhibited human breast cancer cells in vitro and in vivo. In addition, oridonin significantly induced human breast cancer cells apoptosis. Furthermore, the oridonin treatment not only inhibited cancer cell migration and invasion, but more significantly, decreased the expression of Notch 1-4 protein. Conclusion: Our results suggest that the inhibitive effect of oridonin is likely to be driven by the inhibition of Notch signaling pathway and the resulting increased apoptosis.

Antiangiogenic effects of oridonin

Background

Oridonin, the major terpene found in Rabdosia rubescens (Henmsl.) Hara, is widely used as a dietary supplement and therapeutic drug. Oridonin has been proven to possess good anti-tumour activity, but little is known about its effect on angiogenesis. The aim of this study was to investigate the antiangiogenic effects of oridonin in vivo and in vitro and prove that oridonin anti-tumour activity is based on suppressing angiogenesis.

Methods

In vitro, the antiangiogenesis effect was studied by proliferation, apoptosis, migration, invasion, and tube formation experiments on human umbilical vascular endothelial cells (HUVECs). In vivo, using the Tg (fli1: GFP) zebrafish model, the embryonic vasculogenesis and postnatal regeneration were evaluated. The vascular endothelial growth factor (VEGF) signalling pathway gene expressions were assessed by reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, the inhibition effects on tumour growth and metastasis were observed using a xenograft zebrafish tumour model and xenograft nude mouse tumour model. Angiogenesis was assayed by immunostaining with cluster of differentiation 31. Importantly, the proteins were identified as being differentially expressed in an in vivo model by two-dimensional electrophoresis-mass spectrometry (2D–MS) and western blot (WB).

Results

The results indicated that oridonin inhibited HUVEC proliferation, migration, invasion, and tube formation and induced cell apoptosis. Oridonin inhibited zebrafish angiogenesis during embryonic development and tail fin regeneration. RT-PCR showed that oridonin decreased the VEGFA, VEGFR2, and VEGFR3 expressions in zebrafish, while the TP53 expression increased. Moreover, oridonin had strong effects on tumour growth and metastasis in vivo. 2D–MS identified a total of 50 proteins differentially expressed (17 up-expressed, 28 down-expressed). Lastly, WB showed that Claudin 1, Claudin 4, and Claudin 7 were closely related to tumour growth and metastasis.

Conclusion

This study demonstrated that oridonin could inhibit tumour growth and metastasis, which mainly based on oridonin antiangiogenic effects. Claudin 1, Claudin 4, and Claudin 7 were the main contributors to the mechanism.

Triple-negative breast cancer: New therapeutic options via signalling transduction cascades

Triple-negative breast cancer is a highly aggressive type of mammalian carcinoma. It is defined by a rather weak expression of estrogen-, progesterone- and Her2-receptor, and is thus difficult to treat, resulting in low disease-free and overall survival rates of the affected patients. Hence it is important to find new therapeutic options. To this aim we analysed the incidence of some molecules from different signal transduction cascades by immunohistochemistry, which are known to correlate with triple-negative breast cancer, and correlated the expression of these molecules to different tumour traits, such as size, grading, menopausal stage, histology, lymph node affection, remote metastasis formation, and to the incidence of local and lymph node recurrence and metastasis by statistical analysis. Statistically significant correlations were found for a number of tumour characteristics and signalling molecules: HIF1α is correlated to tumour grading, β-catenin to the menopausal state of the patient, and for Notch1 a relation to lymph node affection is seen. In terms of different recurrences, a correlation of β-catenin to metastasis formation and lymph node affection could be shown, as well as coherences between XBP1 and lymph node recurrence, Notch1 and metastasis formation and FOXP3 and the occurrence of local recurrence. The presented results are in accordance with formerly published studies and therefore might comprise opportunities to develop new therapeutical strategies, which could help to handle this aggressive form of breast cancer in a manner, by which side effects would be reduced and therapeutical efficiency is increased.

VEGF165 induces differentiation of hair follicle stem cells into endothelial cells and plays a role in in vivo angiogenesis

Within the vascular endothelial growth factor (VEGF) family of five subtypes, VEGF165 secreted by endothelial cells has been identified to be the most active and widely distributed factor that plays a vital role in courses of angiogenesis, vascularization and mesenchymal cell differentiation. Hair follicle stem cells (HFSCs) can be harvested from the bulge region of the outer root sheath of the hair follicle and are adult stem cells that have multi-directional differentiation potential. Although the research on differentiation of stem cells (such as fat stem cells and bone marrow mesenchymal stem cells) to the endothelial cells has been extensive, but the various mechanisms and functional forms are unclear. In particular, study on HFSCs' directional differentiation into vascular endothelial cells using VEGF165 has not been reported. In this study, VEGF165 was used as induction factor to induce the differentiation from HFSCs into vascular endothelial cells, and the results showed that Notch signalling pathway might affect the differentiation efficiency of vascular endothelial cells. In addition, the in vivo transplantation experiment provided that HFSCs could promote angiogenesis, and the main function is to accelerate host-derived neovascularization. Therefore, HFSCs could be considered as an ideal cell source for vascular tissue engineering and cell transplantation in the treatment of ischaemic diseases.

Oridonin induces G2/M cell cycle arrest and apoptosis via the PI3K/Akt signaling pathway in hormone-independent prostate cancer cells

Oridonin is an active constituent isolated from the traditional Chinese herb Rabdosia rubescens, which exerts antitumor effects in experimental and clinical settings. However, its antitumor effects and underlying mechanisms on prostate cancer cells have not yet been clearly identified. In the present study, the androgen-independent prostate cancer PC3 and DU145 cell lines were used as models to investigate the effects and possible mechanisms of oridonin on cellular proliferation and apoptosis. Results demonstrated that oridonin inhibited cellular proliferation, and was able to significantly induce G₂/M cell cycle arrest and apoptosis. Detailed signaling pathway analysis by western blotting demonstrated that the expression levels of p53 and p21 were upregulated, whereas the expression of cyclin-dependent kinase 1 was downregulated following oridonin treatment, which led to cell cycle arrest in the G₂/M phase. Oridonin also upregulated the proteolytic cleaved forms of caspase-3, caspase-9 and poly (ADP-ribose) polymerase. Furthermore, the protein expression levels of B-cell lymphoma 2 were decreased and those of Bcl-2-associated X protein were increased following oridonin treatment. In addition, oridonin treatment significantly inhibited the expression of phosphoiniositide-3 kinase (PI3K) p85 subunit and the phosphorylation of Akt. The downstream gene murine double minute 2 was also downregulated, which may contribute to the elevated expression of p53 following oridonin treatment. In conclusion, the results of the present study suggested that oridonin is able to inactivate the PI3K/Akt pathway and activate p53 pathways in prostate cancer cells, resulting in the suppression of proliferation and the induction of caspase-mediated apoptosis.

A novel synthetic small molecule YF-452 inhibits tumor growth through antiangiogenesis by suppressing VEGF receptor 2 signaling

Tumor angiogenesis is characterized by abnormal vessel morphology, endowing tumor with highly hypoxia and unresponsive toward treatment. To date, mounting angiogenic factors have been discovered as therapeutic targets in antiangiogenic drug development. Among them, vascular endothelial growth factor receptor 2 (VEGFR2) inhibitors exerts potent antiangiogenic activity in tumor therapy. Therefore, it may provide a valid strategy for cancer treatment through targeting the tumor angiogenesis via VEGFR2 pathway. In this study, we established a high-profile compounds library and certificated a novel compound named N-(N-pyrrolidylacetyl)-9-(4-bromobenzyl)-1,3,4,9-tetrahydro-β-carboline (YF-452), which remarkably inhibited the migration, invasion and tube-like structure formation of human umbilical vein endothelial cells (HUVECs) with little toxicity invitro. Rat thoracic aorta ring assay indicated that YF-452 significantly blocked the formation of microvascular exvivo. In addition, YF-452 inhibited angiogenesis in chick chorioallantoic membrane (CAM) and mouse corneal micropocket assays. Moreover, YF-452 remarkably suppressed tumor growth in xenografts mice model. Furthermore, investigation of molecular mechanism revealed that YF-452 inhibited VEGF-induced phosphorylation of VEGFR2 kinase and the downstream protein kinases including extracellular signal regulated kinase (ERK), focal adhesion kinase (FAK) and Src. These results indicate that YF-452 inhibits angiogenesis and may be a potential antiangiogenic drug candidate for cancer therapy.

Oridonin inhibition and miR‑200b‑3p/ZEB1 axis in human pancreatic cancer

The relationship among oridonin, miR-200b-3p and pancreatic cancer on epithelial-to-mesenchymal transition (EMT) was investigated for the molecular mechanism or signaling pathways on the migration in pancreatic cancer. BxPC-3 and PANC-1 cells were cultivated and the IC50 of oridonin in BxPC-3 and PANC-1 cells were obtained by the CCK-8 array. The expression of miR‑200b-3p was verified by using real-time PCR and its target gene was predicted. BxPC-3 and PANC-1 cells were treated with oridonin or transfected by miR-200b-3p, those cells were used for western blot assay, Transwell assay, ELISA, immunofluorescence staining, tumorigenesis assay in nude mice and immunohistochemical assay to verify the effects of oridonin or miR-200b-3p on pancreatic cancer. We found that oridonin inhibited the proliferation of BxPC-3 and PANC-1 cells in a dose-dependent manner. miR-200b-3p was downregulated by oridonin in BxPC-3 and PANC-1 cells. ZEB1 was a target gene for miR-200b-3p. Oridonin or overexpression of miR‑200b-3p can inhibit the cell migration in BxPC-3 and PANC-1 cells. miR-200b-3p can inhibit the EMT and oridonin can inhibit the expression of ZEB1, N-cadherin and fibronectin but not increase the expression of E-cadherin, while the cell adhesion molecules ICAM-1 and VCAM-1 were decreased by oridonin in BxPC-3 and PANC-1 cells and the cytoskeleton was altered by oridonin in PANC-1 cells compared with the control. In summary, the results demonstrate that miR‑200b-3p was able to inhibit the EMT of human pancreatic cancer in vivo and in vitro by targeted ZEB1. In vitro, oridonin had a certain effect on the migration in BxPC-3 and PANC-1 cells, but not though type III EMT by miR-200-3p/ZEB1 axis, and may be related to type Ⅱ EMT, tumor microenvironment or altering the cytoskeleton. In vivo, oridonin inhibited the cancer migration in the nude mouse model though inhibiting EMT.

Oridonin, a Promising ent-Kaurane Diterpenoid Lead Compound

Oridonin belongs to ent-kaurane tetracyclic diterpenoid and was first isolated from Isodon species. It exhibits inhibitory activities against a variety of tumor cells, and pharmacological study shows that oridonin could inhibit cell proliferation, DNA, RNA and protein synthesis of cancer cells, induce apoptosis and exhibit an antimutagenic effect. In addition, the large amount of the commercially-available supply is also very important for the natural lead oridonin. Moreover, the good stability, suitable molecular weight and drug-like property guarantee its further generation of a natural-like compound library. Oridonin has become the hot molecule in recent years, and from the year 2010, more than 200 publications can be found. In this review, we summarize the synthetic medicinal chemistry work of oridonin from the first publication 40 years ago and share our research experience of oridonin for about 10 years, which may provide useful information to those who are interested in this research field.

Identification and comparative oridonin metabolism in different species liver microsomes by using UPLC-Triple-TOF-MS/MS and PCA

Oridonin (ORI) is an active natural ent-kaurene diterpenoid ingredient with notable anti-cancer and anti-inflammation activities. Currently, a strategy was developed to identify metabolites and to assess the metabolic profiles of ORI in vitro using ultra-high-performance liquid chromatography-Triple/time-of-flight mass spectrometry (UPLC-Triple-TOF-MS/MS). Meanwhile, the metabolism differences of ORI in the liver microsomes of four different species were investigated using a principal component analysis (PCA) based on the metabolite absolute peak area values as the variables. Based on the proposed methods, 27 metabolites were structurally characterized. The results indicate that ORI is universally metabolized in vitro, and the metabolic pathway mainly includes dehydration, hydroxylation, di-hydroxylation, hydrogenation, decarboxylation, and ketone formation. Overall, there are obvious inter-species differences in types and amounts of ORI metabolites in the four species. These results will provide basic data for future pharmacological and toxicological studies of ORI and for other ent-kauranes diterpenoids. Meanwhile, studying the ORI metabolic differences helps to select the proper animal model for further pharmacology and toxicological assessment.

Oridonin inhibits pancreatic cancer cell migration and epithelial-mesenchymal transition by suppressing Wnt/β-catenin signaling pathway

BACKGROUND

Oridonin (ORI) can inhibit proliferation and migration in various types of cancer cell lines. However, the exact mechanism remains unclear. We investigated the migration inhibitory effect of ORI on human pancreatic cancer SW1990 cells and dissected the possible molecular mechanism(s).

METHODS

CCK-8 assay was used to observe the cell viability. Wound healing assay, transwell assay and spontaneous metastasis model were used to observe the migration activities. Real-time PCR, immunofluorescence, western blot analysis and immunohistochemistry methods were used to observe the expression of genes or proteins.

RESULTS

ORI inhibited the migration of SW1990 cells. Real-time PCR and immuno-fluorescence analyses of epithelial-to-mesenchymal transition (EMT) markers were compared between control group and ORI group. The expression of mesenchymal molecular markers, such as vimentin, snail and slug decreased. The expression of epithelial-related marker E-cadherin increased. Wnt/β-catenin signalling was inhibited by ORI using luciferase reporter assay. ORI can decrease the β-catenin protein level not only in the nucleus, but also in the cytoplasm and the whole cell after the treatment with ORI and glycogen synthase kinase 3β (GSK3β) was increased in the ORI-treated group. CHIR could attenuate the effects of ORI in SW1990 cells. We established a mice model by injecting 1 × 10(6) SW1990 cells into nude mice intraperitoneally to test whether ORI affects tumour metastasis. Metastatic formation was inhibited by ORI (5 and 10 mg/kg) compared with the control group. Tumour sections stained with anti-E-cadherin, anti-vimentin and anti-β-catenin antibodies revealed that ORI inhibited EMT, as well as the Wnt/β-catenin pathway in vivo.

CONCLUSIONS

ORI can inhibit pancreatic cancer cell SW1990 migration and EMT by down-regulating Wnt/β-catenin signal transduction in vitro and in vivo. Therefore, it can be potentially and effectively used in the clinical management of pancreatic cancer.

Probing the Anticancer Action of Oridonin with Fluorescent Analogues: Visualizing Subcellular Localization to Mitochondria

Oridonin (1) is a complex ent-kaurane diterpenoid exhibiting remarkable antitumor activity. However, the detailed mechanism or cellular target that underlies this activity has not yet been identified. Herein, we report an efficient approach for exploring the anticancer mechanism of oridonin through development of the potent fluorescent analogues. A series of novel fluorescent oridonin probes linked with coumarin moieties were designed, synthesized, and characterized. Fluorescence microscopy and confocal imaging studies suggested that fluorescent oridonin probe 17d was rapidly taken up into tumor cells and the mitochondrion was the main site of its accumulation. Moreover, we confirmed that cytochrome c played an important role in oridonin induced mitochondrion-mediated apoptosis and α,β-unsaturated ketone is the active moiety of oridonin, which is crucial to its uptake, localization, and cytotoxicity. Our results provide new insights on the molecular mechanism of oridonin and would be useful for its further development into an antitumor agent.

Grb2-associated binder-2 gene promotes migration of non-small cell lung cancer cells via Akt signaling pathway

Early stages of non-small cell lung cancer (NSCLC) can be successfully treated by surgical resection of the tumor, but there is still no effective treatment once it is progressed to metastatic phases. Investigation of NSCLC cancer cell migration, metastasis and development of strategies to block this process is essential to improve the disease prognosis. In the present study, we found that GRB2-associated-binding protein 2 (Gab2) is involved in the migration of NSCLC cells and demonstrated that Gab2 disruption impairs NSCLC cells migration. The requirement of Gab2 in the migration of NSCLC was further confirmed by gene silencing in vitro. In corresponding to this result, over-expression of Gab2 significantly promoted the migratory of NSCLC cells. Finally, we found that Gab2 promotes NSCLC migration through the protein kinase B (Akt) signaling pathway and up-regulation the activity of matrix metallopeptidase (MMP)-2/9. To conclude, our findings suggest a novel mechanism underlying the migration of NSCLC cells which might serve as a new intervention target for the treatment of NSCLC.

Oridonin derivative ameliorates experimental colitis by inhibiting activated T-cells and translocation of nuclear factor-kappa B

OBJECTIVE

To confirm the potential therapeutic efficacy of HAO472 against inflammatory bowel disease (IBD), we investigated the modulatory functions of HAO472 in a mouse model of trinitrobenzene sulfonic acid (TNBS)-induced colitis.

METHODS

Colitis was induced via an intrarectal injection of TNBS in mice. HAO472 (5.0 mg/kg or 7.5 mg/kg) or 1 mg/kg dexamethasone (DX) was injected intraperitoneally into the mice after the TNBS administration. Behavioral and weight changes, macroscopic and histological assessments of colon, the expressions of tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-17A, cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) in the colonic tissues were evaluated. The effect of HAO472 on NF-κB signaling pathway in lymphocytes was also invesigated.

RESULTS

HAO472 significantly ameliorated the clinical symptoms, reduced the severity of the inflammation and decreased mortality in the mouse model. HAO472 also reduced TNF-α, IFN-γ, IL-17A, iNOS/COX-2 and lymphocyte proliferation. These changes were associated with a significant decrease in NF-κB p65 expression and activity.

CONCLUSION

HAO472 has positive effects on TNBS-induced colitis by modulating the subsets and functions of lymphocytes, suppressing inflammation and inhibiting the nuclear translocation of NF-κB p65 subunits.

Targeting of proangiogenic signalling pathways in chronic inflammation

Angiogenesis is de novo capillary outgrowth from pre-existing blood vessels. This process not only is crucial for normal development, but also has an important role in supplying oxygen and nutrients to inflamed tissues, as well as in facilitating the migration of inflammatory cells to the synovium in rheumatoid arthritis, spondyloarthritis and other systemic autoimmune diseases. Neovascularization is dependent on the balance of proangiogenic and antiangiogenic mediators, including growth factors, cytokines, chemokines, cell adhesion molecules and matrix metalloproteinases. This Review describes the various intracellular signalling pathways that govern these angiogenic processes and discusses potential approaches to interfere with pathological angiogenesis, and thereby ameliorate inflammatory disease, by targeting these pathways.

Multiple myeloma cells modify VEGF/IL-6 levels and osteogenic potential of bone marrow stromal cells via Notch/miR-223

Bone marrow mesenchymal stromal cells (BMMSCs) represent a crucial component of multiple myeloma (MM) microenvironment supporting its progression and proliferation. Recently, microRNAs have become an important point of interest for research on micro-environmental interactions in MM with some evidence of tumor supportive roles in MM. In this study, we examined the role of miR-223 for MM support in BMMSCs of 56 patients with MM (MM-BMMSCs). miR-223 expression in MM-BMMSCs was reduced by the presence of MM cells in vitro in a cell-contact dependent manner compared to mono-cultured MM-BMMSCs. Co-cultivation of MM cells and MM-BMMSCs induced activation of notch amongst others via jagged-2/notch-2 leading to increased expression of Hes1, Hey2, or Hes5 in both cell types. Cultivation of MM-BMMSCs with increasing levels of recombinant jagged-2 reduced miR-223 and increased Hes1 levels in a concentration-dependent manner. Transient reduction of miR-223 levels increased VEGF and IL-6 expression and secretion by MM-BMMSCs. In addition, reduction of miR-223 degraded the osteogenic differentiation potential of MM-BMMSCs. Inhibition of notch signaling induced apoptosis in both MM cells and MM-BMMSCs. Furthermore, it increased miR-223 levels and reduced expression of VEGF and IL-6 by both cell types. These data provide first evidence that miR-223 participates in different MM supporting pathways in MM-BMMSCs inlcuding regulation of cytokine secretion and expression as well as osteogenic differentiation of MM-BMMSCs. More insights on the role of miR-223 in MM-BMMSCs and in cellular interactions between MM cells and MM-BMMSCs could provide starting points for a more efficient anti-myeloma treatment by targeting of notch signaling. © 2015 Wiley Periodicals, Inc.

Grb2-associated binder 2 silencing impairs growth and migration of H1975 cells via modulation of PI3K-Akt signaling

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related death and often has a poor prognosis. Investigation of NSCLC cancer cell migration, invasion and development of strategies to block this process is essential to improve the disease prognosis. In this study, we tested our hypothesis that Grb2-associated binder 2 (Gab2) regulate NSCLC cancer cell H1975 malignant biological behaviors, and silencing Gab2 reduced H1975 cellular colony forming ability, migration and invasion. Moreover, silenced cells present defects in phosphatidylinositol 3-kinase (PI3K)-serine/threonine kinase (Akt) signaling, and reduced expression/activity of matrix metallopeptidase (MMP)-2/9. Furthermore, in Gab2 siRNA-transfected cells, we detected a decrease in signal transducer and activator of transcription 3 (STAT3) phosphorylation and nuclear translocation. In vivo, Gab2 siRNA cells inoculated subcutaneously in nude mice demonstrated decreased tumor growth and PI3K-Akt signaling inhibition. These results indicate that Gab2 is a key factor in H1975 tumor migration, invasion, suggesting that Gab2 can be a novel therapeutic target in NSCLC.

Rhamnazin, a novel inhibitor of VEGFR2 signaling with potent antiangiogenic activity and antitumor efficacy

Anti-angiogenesis targeting vascular endothelial growth factor receptor 2 (VEGFR2) has emerged as an important tool for cancer therapy. The identification of new drugs from natural products has a long and successful history. In this study, we described a novel VEGFR2 inhibitor, rhamnazin, which inhibits tumor angiogenesis and growth. Rhamnazin significantly inhibited proliferation, migration and tube formation of human umbilical vascular endothelial cells (HUVECs) in vitro as well as inhibited sprouts formation of rat aorta ring. In addition, it inhibited vascular endothelial growth factor (VEGF)-induced phosphorylation of VEGFR2 and its downstream signaling regulator in HUVECs. Moreover, rhamnazin could directly inhibit proliferation of breast cancer cells MDA-MB-231 in vitro and in vivo. Oral administration of rhamnazin at a dose of 200 mg/kg/day could markedly inhibited human tumor xenograft growth and decreased microvessel densities (MVD) in tumor sections. Taken together, these preclinical evaluations suggest that rhamnazin inhibits angiogenesis and may be a promising anticancer drug candidate.