Oridonin derivatives as potential anticancer drug candidates triggering apoptosis through mitochondrial pathway in the liver cancer cells

Oridonin impedes breast cancer growth by blocking cells in S phase and inhibiting the PI3K/AKT/mTOR signaling pathway

Breast cancer is one of the most common cancers. Oridonin, a traditional Chinese medicine, is believed to inhibit tumor growth, but its particular effects on breast cancer remain unknown. In this study, we examined oridonin's effects on 4T1, MCF-7, and MDAMB-231 cellular activity using CCK8. Scratch assays were used to detect oridonin's effects on cellular migration. Oridonin's effects on the breast cancer cell cycle were studied using flow cytometry, and expression of cell cycle related proteins p53, CDK2, and p21 was detected using Western blot assays. Metabolomics assays were used to detect changes in small molecule metabolites and metabolic pathways in breast cancer cells after treatment with oridonin. Oridonin's effects on breast cancer growth were also studied using xenograft mice. Metabolomics assays were used to detect changes in metabolites and metabolic pathways in xenograft mouse plasma in a control group, model group, and drug administration group. Experimental results showed that oridonin could significantly inhibit breast cancer growth both in vivo and in vitro. Scratch experiments showed that oridonin could inhibit breast cancer cell migration. Oridonin was also able to arrest cells in S phase by affecting several cell cycle-related proteins, including p53, CDK2, and p21. Metabolomic analysis of 4T1 cells identified a total of 33 differential metabolites, including multiple amino acids (such as l-Glutamic acid, l-Asparagine, l-Histidine, l-Valine, and l-Isoleucine). KEGG pathway enrichment analysis showed significant changes in aminoacyl-tRNA biosynthesis, and in multiple amino acid metabolic pathways. Plasma metabolomic analyses of xenograft mice revealed 28 differentially-expressed metabolites between the different animal model groups, including multiple amino acids. KEGG pathway analysis showed significant alterations in multiple amino acid metabolic pathways in oridonin-treated mice. Additionally, changes in the expression of PI3K, AKT and mTOR proteins, as well as in branched amino acids, suggest that oridonin affects the PI3K/AKT/mTOR signaling pathway by inhibiting the biosynthesis of valine, leucine and isoleucine. Taken together, our results suggest that oridonin has strong anti-tumor activity in vitro and in vivo, and has potential as an adjuvant to breast cancer treatment regimens.

Oridonin promotes endoplasmic reticulum stress via TP53-repressed TCF4 transactivation in colorectal cancer

BACKGROUND

The incidence of colorectal cancer and cancer death rate are increasing every year, and the affected population is becoming younger. Traditional Chinese medicine therapy has a unique effect in prolonging survival time and improving the prognosis of patients with colorectal cancer. Oridonin has been reported to have anti-cancer effects in a variety of tumors, but the exact mechanism remains to be investigated.

METHODS

Cell Counting Kit-8 assay (CCK8) and 5-Ethynyl-2'-deoxyuridine (EdU) staining assay, Tranwell, and Wound healing assays were performed to measure cell proliferation, invasion, and migration capacities, respectively. The protein and mRNA expression levels of various molecules were reflected by Western blot and Reverse Transcription quantitative Polymerase Chain Reaction (qRT-PCR). Transcription Factor 4 (TCF4) and its target genes were analyzed by Position Weight Matrices (PWMs) software and the Gene Expression Omnibus (GEO) database. Immunofluorescence (IF) was performed to visualize the expression and position of Endoplasmic Reticulum (ER) stress biomarkers. The morphology of the ER was demonstrated by the ER tracker-red. Reactive Oxygen Species (ROS) levels were measured using a flow cytometer (FCM) or fluorescent staining. Calcium ion (Ca²⁺) concentration was quantified by Fluo-3 AM staining. Athymic nude mice were modeled with subcutaneous xenografts.

RESULTS

Oridonin inhibited the proliferation, invasion, and migration of colorectal cancer, and this effect was weakened in a concentration-dependent manner by ER stress inhibitors. In addition, oridonin-induced colorectal tumor cells showed increased expression of ER stress biomarkers, loose morphology of ER, increased vesicles, and irregular shape. TCF4 was identified as a regulator of ER stress by PWMs software and GEO survival analysis. In vitro and in vivo experiments confirmed that TCF4 inhibited ER stress, reduced ROS production, and maintained Ca²⁺ homeostasis. In addition, oridonin also activated TP53 and inhibited TCF4 transactivation, further exacerbating the elevated ROS levels and calcium ion release in tumor cells and inhibiting tumorigenesis in colorectal cancer cells in vivo.

CONCLUSIONS

Oridonin upregulated TP53, inhibited TCF4 transactivation, and induced ER stress dysregulation in tumor cells, promoting colorectal cancer cell death. Therefore, TCF4 may be one of the important nodes for tumor cells to regulate ER stress and maintain protein synthesis homeostasis. And the inhibition of the TP53/TCF4 axis plays a key role in the anti-cancer effects of oridonin.

Natural-product-based fluorescent probes: recent advances and applications

Fluorescent probes are attractive tools for biology, drug discovery, disease diagnosis, and environmental analysis. In bioimaging, these easy-to-operate and inexpensive probes can be used to detect biological substances, obtain detailed cell images, track in vivo biochemical reactions, and monitor disease biomarkers without damaging biological samples. Over the last few decades, natural products have attracted extensive research interest owing to their great potential as recognition units for state-of-the-art fluorescent probes. This review describes representative natural-product-based fluorescent probes and recent discoveries, with a particular focus on fluorescent bioimaging and biochemical studies.

Oridonin attenuates low shear stress-induced endothelial cell dysfunction and oxidative stress by activating the nuclear factor erythroid 2-related factor 2 pathway

Background

Atherosclerosis (AS) is the primary cause of cardiovascular disease and the incidence is extremely common; however, there are currently few drugs that can effectively treat AS. Although oridonin has been widely used to treat inflammation and cancer for numerous years, to the best of our knowledge, its protective effect against AS has not been reported. Therefore, the present study aimed to investigate whether oridonin attenuated AS.

Methods

By using text mining, chemometric and chemogenomic methods, oridonin was predicted to be a beneficial agent for the treatment of AS. A parallel flow chamber was used to establish a low shear stress (LSS)-induced endothelial cell (EC) dysfunction model. Briefly, ECs were exposed to 3 dyn/cm² LSS for 30 min and subsequently treated with oridonin or transfected with a small interfering RNA (siRNA) targeting nuclear factor erythroid 2-related factor 2 (NRF2). Reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH) and glutathione disulfide (GSSG) in EA.hy926 cells were analyzed to determine the level of oxidative stress. The nitric oxide (NO) levels and mRNA expression levels of endothelial NO synthase (eNOS), endothelin-1 (ET-1) and prostaglandin synthase (PGIS) in EA.hy926 cells were analyzed to determine EC dysfunction. Furthermore, the mRNA and protein expression levels of NRF2 were analyzed using reverse transcription-quantitative PCR and western blot. In addition, zebrafish were fed with a high-cholesterol diet to establish a zebrafish AS model, which was used to observe lipid accumulation and inflammation under a fluorescence microscope.

Results

We found LSS led to oxidative stress and EC dysfunction; this was primarily indicated through the significantly decreased SOD and GSH content, the significantly increased MDA, GSSG and ROS content, the upregulated mRNA expression levels of ET-1, and the downregulated NO levels and mRNA expression levels of eNOS and PGIS in ECs. Notably, oridonin could improve LSS-induced oxidative stress and EC dysfunction, and the effects of oridonin were reversed by the transfection with NRF2 siRNA. Oridonin also attenuated lipid accumulation and neutrophil recruitment at the LSS regions in the zebrafish AS model.

Conclusions

In conclusion, the results of the present study suggested that oridonin may ameliorate LSS-induced EC dysfunction and oxidative stress by activating NRF2, thereby attenuating AS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03658-2.

Potential Focal Adhesion Kinase Inhibitors in Management of Cancer: Therapeutic Opportunities from Herbal Medicine

Focal adhesion kinase (FAK) is a multifunctional protein involved in cellular communication, integrating and transducing extracellular signals from cell-surface membrane receptors. It plays a central role intracellularly and extracellularly within the tumor microenvironment. Perturbations in FAK signaling promote tumor occurrence and development, and studies have revealed its biological behavior in tumor cell proliferation, migration, and adhesion. Herein we provide an overview of the complex biology of the FAK family members and their context-dependent nature. Next, with a focus on cancer, we highlight the activities of FAK signaling in different types of cancer and how knowledge of them is being used for screening natural compounds used in herbal medicine to fight tumor development.

Spirolactone-type and enmein-type derivatives as potential anti-cancer agents derived from oridonin

Natural products (NPs) are always the important sources in the field of drug discovery, among which spirolactone-type and enmein-type compounds exhibit a wide range of biological activities, especially anti-tumor activity. Based on previous studies, the spirolactone-type and enmein-type compounds could be derived from natural oridonin (1) by several chemical reactions. Herein, a series of novel spirolactone-type and enmein-type derivatives with different aryl allyl ester substitutions at their C-14 hydroxyl group were designed and synthesized. The anti-tumor activity results showed that most of the compounds exhibited better anti-proliferative activities than parent compound oridonin, and the most potent compound had an IC₅₀ value of 0.40 μM in K562 cells. Further mechanistic studies revealed that the optimal compound could arrest K562 cells at G2/M phase by inhibiting cdc-2, cdc-25c and cyclin B1 expression. In addition, the optimal compound induced apoptosis in K562 cells through increasing ROS production and depolarizing mitochondrial membrane potential. Collectively, these valuable results suggested that the most potent compound could be an anti-tumor agent candidate and is worthy of further investigation.

Traditional Medicinal Plants as a Source of Inspiration for Osteosarcoma Therapy

Osteosarcoma is one of the most common types of bone cancers among paediatric patients. Despite the advances made in surgery, chemo-, and radiotherapy, the mortality rate of metastatic osteosarcoma remains unchangeably high. The standard drug combination used to treat this bone cancer has remained the same for the last 20 years, and it produces many dangerous side effects. Through history, from ancient to modern times, nature has been a remarkable source of chemical diversity, used to alleviate human disease. The application of modern scientific technology to the study of natural products has identified many specific molecules with anti-cancer properties. This review describes the latest discovered anti-cancer compounds extracted from traditional medicinal plants, with a focus on osteosarcoma research, and on their cellular and molecular mechanisms of action. The presented compounds have proven to kill osteosarcoma cells by interfering with different pathways: apoptosis induction, stimulation of autophagy, generation of reactive oxygen species, etc. This wide variety of cellular targets confer natural products the potential to be used as chemotherapeutic drugs, and also the ability to act as sensitizers in drug combination treatments. The major hindrance for these molecules is low bioavailability. A problem that may be solved by chemical modification or nano-encapsulation.

iRGD Tumor-Penetrating Peptide-Modified Nano-Delivery System Based on a Marine Sulfated Polysaccharide for Enhanced Anti-Tumor Efficiency Against Breast Cancer

Background

Breast cancer is a common malignancy in women. Conventional clinical therapies for breast cancer all display moderate clinical efficacies and limitations. It is urgent to explore the novel and combined therapeutic strategies for breast cancer to meet clinical demand.

Methods

An iRGD tumor-penetrating peptide-modified nano-delivery system (denoted as iRGD-PSS@PBAE@JQ1/ORI nanoparticles) based on a marine sulfated polysaccharide was developed by codelivery of JQ1 (BET inhibitor) and oridonin (ORI, bioactive diterpenoid derived from traditional Chinese medicine herb). The iRGD-PSS@PBAE@JQ1/ORI NPs, surface modified with iRGD peptide conjugated propylene glycol alginate sodium sulfate (iRGD-PSS). The antitumor efficacy was evaluated both in vitro and in vivo.

Results

The prepared iRGD-PSS@PBAE@JQ1/ORI NPs effectively enhanced the tumor targeting and cellular internalization of JQ1 and ORI. Thus, JQ1 exerted the reversal effect on immune tolerance by decreasing the expression of PD-L1, while ORI displayed multiple antitumor effects, such as antiproliferation, inhibition of intracellular ROS production and inhibition of lactic acid secretion.

Conclusion

Our data revealed that iRGD peptide could significantly improve the cellular internalization and tumor penetration of the nano-delivery system. The combination of JQ1 and ORI could exert synergistic antitumor activities. Taken together, this study provides a multifunctional nanotherapeutic system to enhance the anti-tumor efficiency against breast cancer.

Preparation, Characterization, and Evaluation of Liposomes Containing Oridonin from Rabdosia rubescens

Due to the remarkable anti-tumor activities of oridonin (Ori), research on Rabdosia rubescens has attracted more and more attention in the pharmaceutical field. The purpose of this study was to extract Ori from R. rubescens by ultrasound-assisted extraction (UAE) and prepare Ori liposomes as a novel delivery system to improve the bioavailability and biocompatibility. Response surface methodology (RSM), namely Box-Behnken design (BBD), was applied to optimize extraction conditions, formulation, and preparation process. The results demonstrated that the optimal extraction conditions were an ethanol concentration of 75.9%, an extraction time of 35.7 min, and a solid/liquid ratio of 1:32.6. Under these optimal conditions, the extraction yield of Ori was 4.23 mg/g, which was well matched with the predicted value (4.28 mg/g). The optimal preparation conditions of Ori liposomes by RSM, with an ultrasonic time of 41.1 min, a soybean phospholipids/drug ratio of 9.6 g/g, and a water bath temperature of 53.4 °C, had higher encapsulation efficiency (84.1%). The characterization studies indicated that Ori liposomes had well-dispersible spherical shapes and uniform sizes with a particle size of 137.7 nm, a polydispersity index (PDI) of 0.216, and zeta potential of −24.0 mV. In addition, Ori liposomes presented better activity than free Ori. Therefore, the results indicated that Ori liposomes could enhance the bioactivity of Ori, being proposed as a promising vehicle for drug delivery.

Combination of oridonin and TRAIL induces apoptosis in uveal melanoma cells by upregulating DR5

AIM

To investigate the inhibitory effect of the combined use of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and oridonin on choroidal melanoma cell lines, and to explore its underlying mechanism.

METHODS

MUM-2B and C918 cells were treated with different concentrations of TRAIL and oridonin, and MTT assay used to evaluate the inhibition rate of the two compounds on cells. Then, the cell cycle distribution and apoptosis were detected by flow cytometry, and changes in apoptosis-related proteins such as death receptor 5 (DR5), a-caspase-3, and x-linked inhibitor of apoptosis protein (XIAP) were detected by Western blot. MUM-2B cells were transfected with si-DR5, which interfered with the expression of the DR5 gene. MTT and Western blot assay were used to detect cell activity and apoptosis-related proteins.

RESULTS

When TRAIL and oridonin were simultaneously administered to the MUM-2B cells, the apoptosis rate was significantly higher than that by the two drugs individually. However, the effect of combined use of TRAIL and oridonin on C918 cells was not significantly different from that used alone. Cell cycle analysis showed that TRAIL and oridonin could induce G2/M arrest in MUM-2B cells. The Western blot results showed that the protein expression levels of the DR5, a-caspase-3, and BAX increased, while the expression levels of the anti-apoptosis-related proteins XIAP and BCL-2 were suppressed when TRAIL and oridonin simultaneously administered to MUM-2B cells. Interfering the expression of DR5 gene in MUM-2B cells could reverse the inhibitory effect of oridonin and TRAIL on the proliferation and apoptosis induction of MUM-2B cells.

CONCLUSION

The inhibitory effects of oridonin and TRAIL on MUM-2B cells are significantly enhanced when they were administered as a combined treatment, which may ascribe to up-regulation of DR5.

Synthesis, biological evaluation and cellular localization study of fluorescent derivatives of Jiyuan Oridonin A

Jiyuan Oridonin A (JOA) is a naturally occurring ent-kaurane diterpenoid that exhibits significant potential in the field of anti-tumor drug development. However, its detailed anti-cancer mechanism of action has not been fully understood. In order to investigate its anticancer mode of action, two series of novel fluorescent derivatives of JOA conjugated with naphthalimide dyes were synthesized, and their antitumor activity against five selected cancer cell lines (MGC-803, SW1990, PC-3, TE-1 and HGC-27) was evaluated. Compared with JOA, the anti-tumor activity of the vast majority of compounds were improved. Among them, B12 exhibited promising anti-proliferative activity against HGC-27 cells with IC₅₀ value of 0.39 ± 0.09 μM. Fluorescence imaging studies demonstrated that probe B12 could enter HGC-27 cells in a dose-dependent and time-dependent manner and was mainly accumulated in mitochondria. Preliminary biological mechanism studies indicated that B12 was able to inhibit cell cloning and migration. Further studies suggested that B12-induced apoptosis was related to the mitochondrial pathway. Overall, our results provide new approaches to explore the molecular mechanism of the natural product JOA, which would contribute to its further development as an antitumor agent.

Oridonin Alters Hepatic Urea Cycle via Gut Microbiota and Protects against Acetaminophen-Induced Liver Injury

Acetaminophen (APAP) hepatotoxicity is the leading cause of acute liver failure in the western world. Oridonin (OD), which is the major active ingredient of the traditional Chinese medicine Rabdosia rubescens, reportedly exerts anti-inflammatory and antioxidative effects. Here, we first find that OD protects against APAP-induced hepatotoxicity. The results of hepatic tissue-associated RNA-seq and metabolomics showed that the protective effects of OD were dependent upon urea cycle regulation. And such regulation of OD is gut microbiota partly dependent, as demonstrated by fecal microbiota transplantation (FMT). Furthermore, using 16S rRNA sequencing, we determined that OD significantly enriched intestinal Bacteroides vulgatus, which activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway to regulate redox homeostasis against APAP by urea cycle. In conclusion, our study suggests that the Bacteroides vulgatus-urea cycle-Nrf2 axis may be a potential target for reducing APAP-induced liver injury, which is altered by OD.

Side-Chain Selenium-Grafted Polymers Combining Antiangiogenesis Treatment with Photodynamic Therapy and Chemotherapy

The abnormal tumor vasculature in solid tumors creates hypoxia and leads to compromising the delivery and anticancer efficiency of nanomedicine. Nanomaterials with intrinsic antiangiogenesis ability might normalize tumor vessels and improve the therapeutic effect of O₂-related treatment like PDT. Herein, we designed and prepared ROS-responsive side-chain selenium-grafted polymers, which had potential antiangiogenic activity, as vehicles to load photodynamic therapeutic agent Ce6 and chemotherapeutic drug oridonin. Under NIR irradiation, the C-Se bonds on the side chain of polymers could be cleaved in the presence of ¹O₂ produced by Ce6 and further formed organic selenic acid through selenoxide elimination reaction. The generated seleninic acid could downregulate the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP-2) to inhibit angiogenesis and further relieve hypoxia. The released oridonin could significantly increase the intracellular ROS concentration. Both could modulate cancer cells' microenvironment to reinforce PDT. Therefore, these nanomedicines could be a good candidate for synergistic treatments of antiangiogenesis treatment, PDT, and chemotherapy.

Oridonin interrupts cellular bioenergetics to suppress glioma cell growth by down-regulating PCK2

We aim to evaluate the tumor metabolic suppressive activity of Oridonin (extract of Rabdosia rubescens) in glioma and elucidate its potential mechanism. Effects of Oridonin on U251/U87 cells were determined by CCK8, RTCA, colony formation, flow cytometry, wound healing, and Transwell assay. Xenograft tumor model to evaluate the effect of Oridonin on glioma cells in vivo. Cellular bioenergetics were measured by Seahorse. RNA-seq was performed to screen potential biological pathways in Oridonin treated cells. Bioinformatics analysis of PCK2 in glioma was performed based on TCGA/CGGA. Endogenous PCK2 was knocked-down by lentivirus packaged shRNA. We found Oridonin significantly inhibited cell growth in U251/U87 in vitro and in vivo. Both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were decreased in Oridonin-treated U251/U87 cells. Oridonin treatment led to PCK2 down-regulation. Additionally, PCK2 was up-regulated in higher grade glioma and correlated with poor outcomes. Furthermore, PCK2 depletion significantly inhibited cell growth and decreased OCR/ECAR in U251/U87 which coincided with the effects of Oridonin. Therefore, we evaluated the potent anti-tumor property of Oridonin in glioma. Importantly, we demonstrated that PCK2 might be a novel target of Oridonin on glioma by inducing energy crisis and increasing oxidative stress.

Oridonin ameliorates insulin resistance partially through inhibition of inflammatory response in rats subjected to chronic unpredictable mild stress

BACKGROUND

Oridonin (Ori) has multiple biological properties, especially anti-inflammatory. However, its effects on chronic unpredictable mild stress (CUMS)-induced insulin resistance are still unclear. In this study, we explored the regulatory role of Ori in CUMS-triggered insulin resistance, and the underlying molecular mechanisms; Methods: SD rats were subjected to CUMS for 4 weeks, some of which were injected with Ori or fluoxetine (FLX) in durations of CUMS. After CUMS procedure, the behavioral and metabolic tests were performed. Elisa, immunofluorescence and western blotting were used to determine the inflammatory response and NLRP3 inflammasome activation. We investigated the interaction between NLRP3 and NEK7 using immunoprecipitation. Finally, we detected the proinflammatory cytokines in Lipopolysaccharide (LPS)-activated RAW264.7 cells treated with Ori; RESULTS: In this study, we found that chronic stress resulted in depressive-like behavior comorbid with insulin resistance. Ori was discovered to ameliorate insulin resistance as well as insulin signaling disturbance in the hippocampus. In addition, CUMS caused the infiltration of macrophages into the islets. And IL-1β, IL-18 and caspase-1 were elevated in pancreases of CUMS rats, which could also be reversed by Ori treatment via reducing the interaction between NLRP3 and NEK7. Furthermore, Ori dose-dependently inhibited the levels of IL-1β and IL-18 in LPS-activated RAW264.7 cells; CONCLUSIONS: All these results supported our hypothesis that Ori possesses potent anti-insulin resistant actions, which is partially correlated with inhibiting infiltration of macrophages into the islets and NLRP3 activation induced by CUMS. Therefore, our results highlighted the protective role of Ori against CUMS-elicited insulin resistance.

ent-Kaurane-Based Diterpenoids, Dimers, and Meroditerpenoids from Isodon xerophilus

Eight new diterpenoids (1-8) with varied structures were isolated from the aerial parts of Isodon xerophilus. Among them, xerophilsin A (1) was found to be an unusual meroditerpenoid representing a hybrid of an ent-kauranoid and a long-chain aliphatic ester, xerophilsins B-D (2-4) are dimeric ent-kauranoids, while xerophilsins E-H (5-8) are new ent-kauranoids. The structures of 1-8 were elucidated mainly through the analyses of their spectroscopic data. The absolute configurations of 2, 6, and 8 were confirmed by single-crystal X-ray diffraction, and the configuration of C-16 in 7 was established through quantum chemical calculation of NMR chemical shifts, as well as modeling of key interproton distances. Bioactivity evaluation of all isolated compounds revealed that 2, 3, and 5 inhibited NO production in LPS-stimulated RAW264.7 cells.

Oridonin Sensitizes Hepatocellular Carcinoma to the Anticancer Effect of Sorafenib by Targeting the Akt Pathway

Background

Oridonin is the core bioactive component of Rabdosia rubescens, a traditional Chinese herbal medicine used in the treatment of hepatoma. Sorafenib, a targeted therapeutic agent for advanced hepatocellular carcinoma (HCC), has recently been shown to exert limited clinical effects. However, few studies have focused on the synergistic effect of these two drugs on hepatocellular carcinoma.

Methods

We treated different HCC cell lines with different concentrations of oridonin and sorafenib and assessed the viability by using MTT assays and examined proliferation, migration, invasion and apoptosis after cotreatment of HepG2 cells with 20 μM oridonin and 5 μM sorafenib via colony formation assays, Transwell assays and flow cytometry. Regulatory effects were measured by Western blotting. The in vivo synergistic effect was confirmed through xenograft tumor models, and tumor tissues were analyzed by immunohistochemistry.

Results

The inhibitory effects of oridonin and sorafenib cotreatment on HCC cells were stronger than those of either drug alone. In addition, combined treatment with the two drugs synergistically inhibited epithelial–mesenchymal transition and the Akt pathway but not NF-κB or MAPK signaling. Akt phosphorylation by SC79 reversed the inhibitory effects of the combined treatment. Synergistic inhibition was equally observed in vivo.

Conclusion

Oridonin combined with sorafenib synergistically inhibited proliferation, migration, invasion, and epithelial–mesenchymal transition and induced apoptosis by targeting the Akt pathway but not NF-κB or MAPK signaling.

Amentotaxins C-V, Structurally Diverse Diterpenoids from the Leaves and Twigs of the Vulnerable Conifer Amentotaxus argotaenia and Their Cytotoxic Effects

A phytochemical investigation of the MeOH extract of the leaves and twigs of Amentotaxus argotaenia, a relict vulnerable coniferous species endemic to China, led to the isolation and characterization of 35 diterpenoids/norditerpenoids. Twenty of these are new, including 11 ent-kaurane-type (amentotaxins C-M, 1-11, respectively), three icetexane-type [= 9(10→20)abeo-abietane-type (amentotaxins N-P, 12-14, respectively)], four ent-labdane-type (amentotaxins Q-T, 15-18, respectively), and two isopimarane-type [amentotaxins U (19) and V (20)] compounds. Their structures were elucidated on the basis of spectroscopic data, single-crystal X-ray diffraction, the modified Mosher's method, and electronic circular dichroism data analyses. Compounds 1-9 are rare 18-nor-ent-kaurane-type diterpenoids featuring a 4β,19-epoxy ring. All the isolates were evaluated for their cytotoxic effects against a small panel of cultured human cancer cell lines (HeLa, A-549, MDA-MB-231, SKOV3, Huh-7, and HCT-116), and some of them exhibited cytotoxicities with IC₅₀ values ranging from 1.5 to 10.0 μM.

Identification of a Potent Oridonin Analogue for Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is one of the most highly invasive and metastatic breast cancers without safe and effective therapeutic drugs. The natural product oridonin is reported to be a potential anti-TNBC agent. However, its moderate activity and complex structure hampered its clinical application. In this study, the novel oridonin analogues were first identified by removal of multiple hydroxyl groups and structural simplification of oridonin. The representative analogue 20 exhibited potent anticancer effects. Further structural modification on 20 generated the most potent derivative 56, which possessed 120-fold more potent antiproliferative activity than oridonin in the TNBC cell line HCC1806. Importantly, compound 56 exhibited more potent anticancer activity than paclitaxel in TNBC xenograft nude mice. Moreover, 56 could attenuate the expression of MMP-2, MMP-9, p-FAK, and integrin β1 to inhibit TNBC cell metastasis. All results suggest that compound 56 may warrant further investigation as a promising candidate agent for the treatment of TNBC.

Mac-2-binding protein glycan isomer enhances the aggressiveness of hepatocellular carcinoma by activating mTOR signaling

Background

Wisteria floribunda agglutinin (WFA)⁺ Mac-2-binding protein (M2BPGi) is a novel serum marker for liver fibrosis. Although an elevated serum level of M2BPGi can predict development of hepatocellular carcinoma (HCC), the effect of M2BPGi on HCC remains unclear. There are no reports about the association of M2BPGi with HCC aggressiveness. We aimed to clarify the significance of M2BPGi in HCC.

Methods

The protein expression of M2BPGi and galectin-3, a ligand of M2BP, and the mRNA expression of M2BP were evaluated in surgically resected human HCC samples. M2BPGi-regulating signals in HCC cells were investigated using transcriptome analysis. The effects of M2BPGi on HCC properties and galectin-3/mTOR signaling were evaluated.

Results

M2BPGi and galectin-3 proteins co-localised in HCC cells, while M2BP mRNA was detected in cirrhotic liver stromal cells. mTOR signaling was upregulated in M2BPGi-treated HCC cells. Moreover, M2BPGi treatment induced tumour-promoting effects on HCC in vitro by activated mTOR signaling. In addition, M2BPGi bound to galectin-3 to induce membranous galectin-3 expression in HCC cells. In vivo, M2BPGi enhanced the growth of xenografted HCC.

Conclusions

M2BPGi is produced in stromal cells of the cirrhotic liver. Furthermore, M2BPGi enhances the progression of HCC through the galectin-3/mTOR pathway.