Inhibition of caspase-9 by oridonin, a diterpenoid isolated from Rabdosia rubescens, augments apoptosis in human laryngeal cancer cells

Induction of apoptosis by oridonin in nonfunctioning pituitary adenoma cells

Nonfunctioning pituitary adenoma (NFPA) is one of the major subtypes of pituitary adenomas (PA) and its primary treatment is surgical resection. However, normal surgery fails to remove lesions completely and there remains in lack of frontline treatment, so the development of new drugs for NFPA is no doubt urgent. Oridonin (ORI) has been reported to have antitumor effects on a variety of tumors, but whether it could exhibit the same effect on NFPA requires to be further investigated. The effects of ORI on pituitary-derived folliculostellate cell line (PDFS) cell viability, colony formation, proliferation ability, migration, and invasion were examined by Cell Counting Kit-8, colony formation assay, 5‑Ethynyl‑2'‑deoxyuridine proliferation assay, wound-healing assay, and Transwell assay. The differentially expressed genes in the control and ORI-treated groups were screened by transcriptome sequencing analysis and analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment. Cell cycle analysis was performed to detect changes in cell cycle. Annexin V-fluorescein isothiocyanate/propidium iodide staining was performed to detect apoptosis in ORI-treated cells. Western blot assay was performed to detect Bax, Bcl-2, and cleaved Caspase-3 protein expression. ORI inhibited PDFS cell viability and significantly suppressed cell proliferation, migration, and invasion. GO and KEGG results showed that ORI was associated with signaling pathways such as cell cycle and apoptosis in PDFS cells. In addition, ORI blocked cells in G2/M phase and induced apoptosis in PDFS cells. ORI can trigger cell cycle disruption and apoptosis collaboratively in PDFS cells, making it a promising and effective agent for NFPA therapy.

Integrating Epigenetics, Proteomics, and Metabolomics to Reveal the Involvement of Wnt/β-Catenin Signaling Pathway in Oridonin-Induced Reproductive Toxicity

Oridonin is the primary active component in the traditional Chinese medicine Rabdosia rubescens, displaying anti-inflammatory, anti-tumor, and antibacterial effects. It is widely employed in clinical therapy for acute and chronic pharyngitis, tonsillitis, as well as bronchitis. Nevertheless, the clinical application of oridonin is significantly restricted due to its reproductive toxicity, with the exact mechanism remaining unclear. The aim of this study was to investigate the mechanism of oridonin-induced damage to HTR-8/SVneo cells. Through the integration of epigenetics, proteomics, and metabolomics methodologies, the mechanisms of oridonin-induced reproductive toxicity were discovered and confirmed through fluorescence imaging, RT-qPCR, and Western blotting. Experimental findings indicated that oridonin altered m6A levels, gene and protein expression levels, along with metabolite levels within the cells. Additionally, oridonin triggered oxidative stress and mitochondrial damage, leading to a notable decrease in WNT6, β-catenin, CLDN1, CCND1, and ZO-1 protein levels. This implied that the inhibition of the Wnt/β-catenin signaling pathway and disruption of tight junction might be attributed to the cytotoxicity induced by oridonin and mitochondrial dysfunction, ultimately resulting in damage to HTR-8/SVneo cells.

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.

Multi-omics analysis of small RNA, transcriptome, and degradome to identify putative miRNAs linked to MeJA regulated and oridonin biosynthesis in Isodon rubescens

Isodon rubescens has garnered much attention due to its anti-tumor or anti-cancer properties. However, little is known about the molecular mechanism of oridonin biosynthesis leveraging the regulatory network between small RNAs and mRNAs. In this study, the regulatory networks of miRNAs and targets were examined by combining mRNA, miRNA, and degradome. A total of 348 miRNAs, including 287 known miRNAs and 61 novel miRNAs, were identified. Among them, 51 miRNAs were significantly expressed, and 36 miRNAs responded to MeJA. A total of 3066 target genes were associated with 228 miRNAs via degradome sequencing. Multi-omics analysis demonstrated that 27 miRNA-mRNA pairs were speculated to be involved in MeJA regulation, and 36 miRNA-mRNA pairs were hypothesized to be involved in the genotype-dependence of I. rubescens. Furthermore, 151 and 7 miRNA-mRNA modules were likely engaged in oridonin biosynthesis as identified by psRNATarget and degradome sequencing, respectively. Some miRNA-mRNA modules were confirmed via RT-qPCR. Moreover, miRNAs targeting plant hormone signal transduction pathway genes were identified, such as miR156, miR167, miR393, and PC-3p-19822_242. Collectively, our results demonstrate for the first time that miRNAs are identified in I. rubescens, and laid a solid foundation for further research on the molecular mechanism of oridonin biosynthesis mediated by miRNA.

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.

Validation of suitable reference genes by various algorithms for gene expression analysis in Isodon rubescens under different abiotic stresses

Isodon rubescens (Hemsley) H. Hara (Lamiaceae) is a traditional Chinese medicine plant that has been used to treat various human diseases. Oridonin is one of the main active ingredients, and the route of its molecular biosynthesis remains to be determined. The study of gene expression patterns can provide clues toward the understanding of its biological functions. The selection of suitable reference genes for normalizing target gene expression is the first steps in any quantitative real-time PCR (RT-qPCR) gene expression study. Therefore, validation of suitable reference genes is necessary for obtaining reliable results in RT-qPCR analyses of I. rubescens. Here, 12 candidate reference genes were chosen, and their expression stability in different tissues of I. rubescens and in leaves under different abiotic stresses (NaCl, dehydration, SA, MeJA, and ABA) was evaluated using the ∆Ct, NormFinder, GeNorm, BestKeeper, and RankAggreg statistical tools. Analysis using the comprehensive tools of RankAggreg algorithm showed that GADPH, 18S and eIF were stably expressed in different tissues; UBQ, Apt, and HIS; Cycl, UBQ, and PP2A; GADPH, 18S, and eIF; eIF, UBQ, and PP2A; TUB, Cycl, and UBQ; were the best three candidate reference genes for the samples of Dehydration, NaCl, SA, MeJA, and ABA treatment, respectively. While for the concatenated sets of ND (NaCl and dehydration) and SMA (SA, MeJA, and ABA), UBQ, HIS, and TUA; UBQ, eIF and Apt were the three appropriate candidate reference genes, respectively. In addition, the expression patterns of HMGR in different tissues and under different treatments were used to confirm the reliability of the selected reference genes, indicating that the use of an inappropriate reference gene as the internal control will cause results with a large deviation. This work is the first study on the expression stability of reference genes in I. rubescens and will be particularly useful for gene functional research in this species.

Inhibitory Effects of Rabdosia rubescens in Esophageal Squamous Cell Carcinoma: Network Pharmacology and Experimental Validation

Esophageal squamous cell carcinoma (ESCC) is one of the most frequently occurring diseases in the world. Rabdosia rubescens (RR) has been demonstrated to be effective against ESCC; however, the mechanism is unknown. The primary gene modules related to the clinical characteristics of ESCC were initially investigated in this research using weighted gene co-expression network analysis (WCGNA) and differential expression gene (DEG) analysis. We employed network pharmacology to study the hub genes linked with RR therapy on ESCC. A molecular docking simulation was achieved to identify the binding activity of central genes to RR compounds. Lastly, a chain of experimentations was used to verify the inhibitory effect of RR water extract on the ESCC cell line in vitro. The outcomes revealed that CCNA2, TOP2A, AURKA, CCNB2, CDK2, CHEK1, and other potential central targets were therapeutic targets for RR treatment of ESCC. In addition, these targets are over-represented in several cancer-related pathways, including the cell cycle signaling pathway and the p53 signaling pathway. The predicted targets displayed good bonding activity with the RR bioactive chemical according to a molecular docking simulation. In vitro experiments revealed that RR water extracts could inhibit ESCC cells, induce cell cycle arrest, inhibit cell proliferation, increase P53 expression, and decrease CCNA2, TOP2A, AURKA, CCNB2, CDK2, and CHEK1. In conclusion, our study reveals the molecular mechanism of RR therapy for ESCC, providing great potential for identifying effective compounds and biomarkers for ESCC therapy.

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.

Development of natural products for anti-PD-1/PD-L1 immunotherapy against cancer

ETHNOPHARMACOLOGICAL RELEVANCE

The programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint is one of the most promising therapeutic targets for cancer immunotherapy, but several challenges remain in current anti-PD-1/PD-L1 therapy. Natural products, mainly derived from traditional medicine, could improve and expand anti-PD-1/PD-L1 therapy because of their advantages such as large diversity and multi-target effects.

AIM OF THE STUDY

This review summarize natural products, raw extracts, and traditional medicines with pharmacological effects associated with the PD-1/PD-L1 axis, particularly PD-L1.

MATERIALS AND METHODS

Electronic literature databases, including Web of Science, PubMed, and ScienceDirect, and online drugs and chemicals databases, including DrugBank, ZINC, PubChem, STITCH, and CTD, were searched without date limitation by February 2021. 'Natural product or herb or herbal plant or traditional medicine' and 'PD-L1' and 'Cancer immunotherapy' were used as the search keywords. Among 112 articles identified in database searching, 54 articles are full text articles, reporting in silico, in vitro, in vivo and clinical trials. 68 articles included are review articles and grey literature such as thesis and congress abstracts.

RESULTS

Several natural products and traditional medicines have exhibited diverse and multi-functional effects including direct blockade of PD-1/PD-L1 interactions, modulation of PD-L1 expression, and cooperation with PD-1/PD-L1 inhibitors.

CONCLUSION

Natural products and traditional medicines can facilitate the development of more effective and acceptable diverse strategies for anti-PD-1/PD-L1 therapy, but further exploration of natural products and pharmaceutical techniques is required.

Oridonin: A Review of Its Pharmacology, Pharmacokinetics and Toxicity

Oridonin, as a natural terpenoids found in traditional Chinese herbal medicine Isodon rubescens (Hemsl.) H.Hara, is widely present in numerous Chinese medicine preparations. The purpose of this review focuses on providing the latest and comprehensive information on the pharmacology, pharmacokinetics and toxicity of oridonin, to excavate the therapeutic potential and explore promising ways to balance toxicity and efficacy of this natural compound. Information concerning oridonin was systematically collected from the authoritative internet database of PubMed, Elsevier, Web of Science, Wiley Online Library and Europe PMC applying a combination of keywords involving "pharmacology," "pharmacokinetics," and "toxicology". New evidence shows that oridonin possesses a wide range of pharmacological properties, including anticancer, anti-inflammatory, hepatorenal activities as well as cardioprotective protective activities and so on. Although significant advancement has been witnessed in this field, some basic and intricate issues still exist such as the specific mechanism of oridonin against related diseases not being clear. Moreover, several lines of evidence indicated that oridonin may exhibit adverse effects, even toxicity under specific circumstances, which sparked intense debate and concern about security of oridonin. Based on the current progress, future research directions should emphasize on 1) investigating the interrelationship between concentration and pharmacological effects as well as toxicity, 2) reducing pharmacological toxicity, and 3) modifying the structure of oridonin-one of the pivotal approaches to strengthen pharmacological activity and bioavailability. We hope that this review can provide some inspiration for the research of oridonin in the future.

An integrative method based on UHPLC-Q-TOF-MS/MS combined with metabolomics to authenticate Isodon rubescens

Genuine regional drugs have played a vital role in clinical use for a long time. There are differences in traditional Chinese medicines (TCM) from different regions based on their chemical composition. Differences in chemical composition may lead to deviations in therapeutic effects. To our knowledge, to date, there are no effective methods for distinguishing genuine regional drugs based on the differences in their chemical composition. Therefore, establishing an analytical platform for distinguishing the compounds used in TCM from various geographical locations is essential. In this work, an integrated platform based on UPLC-Q-TOF-MS/MS combined with plant metabolomics approach was established for comprehensively distinguishing genuine regional drugs. Isodon rubescens (Hemsl.) Hara, a widely used herbal medicine of China, was chosen for this study and 24 samples from four geographical locations in China were collected. A total of 60 ent-kaurane diterpenoids were tentatively identified, and then the samples from four geographical origins were distinguished using PCA (principal component analysis) and PLS-DA (partial least squares discrimination analysis). Different compounds were identified among the samples collected from the four geographical locations, and 12 of them were regarded as marker compounds responsible for the distinction. Our study highlights the essence and predictive ability of metabolomics in detecting minute differences in the same varieties of TCM samples based on the levels and compositions of their metabolites. These results showed that the analysis using UHPLC-Q-TOF-MS/MS combined with metabolomics could be applied to distinguish the geographical origins and varieties of TCM.

Preparation of oridonin nanocrystals and study of their endocytosis and transcytosis behaviours on MDCK polarized epithelial cells

Context: Oridonin (ORI) has obvious anticancer effects, but its solubility is poor. Nanocrystal (NC) is a novel nano-drug delivery system for increasing bioavailability for ORI. However, the endocytosis and transcytosis behaviours of oridonin nanocrystals (ORI-NCs) through epithelial membrane are still unclear.Objectives: ORI-NCs were prepared and characterized. The in vitro cytotoxicity and endocytosis and transcytosis process on Madin-Darby canine kidney (MDCK) monolayer were investigated.Materials and methods: Anti-solvent precipitation method was adopted in preparation of ORI-NCs. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were adopted to explore crystallography of ORI-NCs. Sulforhodamine B (SRB) method was used to test the inhibition effect on proliferation of MDCK cells. Quantitative analysis by HPLC was performed to study the endocytosis and transcytosis of ORI-NCs and ORI bulk drug, and the process was observed by confocal laser spectrum microscopy (CLSM) and flow cytometry.Results: The particle size of ORI-NCs was about 274 nm. The crystallography form of ORI was not changed after prepared into NCs. The dissolution rate of ORI-NCs was higher than pure ORI in 120 min. At higher concentrations (34, 84 and 135 μg/mL), ORI-NCs significantly reduced the cell viability compared with free ORI (p < 0.05, p < 0.01). ORI-NCs demonstrated higher endocytosis in MDCK cells than free ORI (p < 0.01). In the transport process, ORI-NC was taken up into cells in an intact form, and excreted out from basolateral membrane of polarized epithelial cells in an intact form. The internalization and transmembrane amount increased as a function of time.Conclusions: ORI-NCs transported through the MDCK monolayers in an intact form.

ROS-Mediated Therapeutic Strategy in Chemo-/Radiotherapy of Head and Neck Cancer

Head and neck cancer is a highly genetic and metabolic heterogeneous collection of malignancies of the lip, oral cavity, salivary glands, pharynx, esophagus, paranasal sinuses, and larynx with five-year survival rates ranging from 12% to 93%. Patients with head and neck cancer typically present with advanced stage III, IVa, or IVb disease and are treated with comprehensive modality including chemotherapy, radiotherapy, and surgery. Despite advancements in treatment modality and technique, noisome recurrence, invasiveness, and resistance as well as posttreatment complications severely influence survival rate and quality of life. Thus, new therapeutic strategies are urgently needed that offer enhanced efficacy with less toxicity. ROS in cancer cells plays a vital role in regulating cell death, DNA repair, stemness maintenance, metabolic reprogramming, and tumor microenvironment, all of which have been implicated in resistance to chemo-/radiotherapy of head and neck cancer. Adjusting ROS generation and elimination to reverse the resistance of cancer cells without impairing normal cells show great hope in improving the therapeutic efficacy of chemo-/radiotherapy of head and neck cancer. In the current review, we discuss the pivotal and targetable redox-regulating system including superoxide dismutases (SODs), tripeptide glutathione (GSH), thioredoxin (Trxs), peroxiredoxins (PRXs), nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/keap1), and mitochondria electron transporter chain (ETC) complexes and their roles in regulating ROS levels and their clinical significance implicated in chemo-/radiotherapy of head and neck cancer. We also summarize several old drugs (referred to as the non-anti-cancer drugs used in other diseases for a long time) and small molecular compounds as well as natural herbs which effectively modulate cellular ROS of head and neck cancer to synergize the efficacy of conventional chemo-/radiotherapy. Emerging interdisciplinary techniques including photodynamic, nanoparticle system, and Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy are promising measures to broaden the potency of ROS modulation for the benefit of chemo-/radiotherapy in head and neck cancer.

Oxidative stress and apoptotic effects of copper and cadmium in the zebrafish liver cell line ZFL

•

Oxidative stress and apoptosis created by Cu²⁺ and Cd²⁺ insults were studied in ZFL.

•

Cu²⁺ and Cd²⁺ both created lipid peroxidation, causing oxidative stress in cytoplasm.

•

Mitochondrial superoxide was induced by Cd²⁺ but supressed by Cu²⁺.

•

Cu²⁺ suppressed Casp3 activity, resulting in suppressed the apoptosis.

•

Pre-treatments of low concentration of Cu²⁺ protected the cell from Cd²⁺ insults.

Copper (Cu) and cadmium (Cd) are widely used in industrial activities, resulting in Cu and Cd contamination in aquatic systems worldwide. Although Cu plays an essential role in many biological functions, an excessive amount of the metal causes cytotoxicity. In contrast, Cd is a non-essential metal that usually co-exists with Cu. Together, they cause oxidative stress in cells, leading to cell damage. These metal ions are also believed to cause cell apoptosis. In this study, we used a zebrafish liver cell line, ZFL, to study combined Cu and Cd cytotoxicity. Although Cd is more toxic than Cu, both were found to regulate the expression of oxidative stress related genes, and neither significantly altered the activity of oxidative stress related enzymes. Co-exposure tests with the antioxidant N-acetyl-l-cysteine and the Cu chelator bathocuproinedisulfonic acid disodium salt demonstrated that Cd toxicity was due to the oxidative stress caused by Cu, and that Cu at a low concentration could in fact exert an antioxidant effect against the oxidative stress in ZFL. Excessive Cu concentration triggered the expression of initiator caspases (caspase 8 and caspase 9) but suppressed that of an executioner caspase (caspase 3), halting apoptosis. Cd could only trigger the expression of initiator caspases; it could not halt apoptosis. However, a low concentration of Cu reduced the mitochondrial superoxide level, suppressing the Cd-induced apoptotic effects in ZFL.

Molecular mechanisms of apoptosis and autophagy elicited by combined treatment with oridonin and cetuximab in laryngeal squamous cell carcinoma

Combined oridonin (ORI), a natural and safe kaurene diterpenoid isolated from Rabdosia rubescens, and cetuximab (Cet), an anti-EGFR monoclonal antibody, have been reported to exert synergistic anti-tumor effects against laryngeal squamous cell carcinoma (LSCC) both in vitro and in vivo by our group. In the present study, we further found that ORI/Cet treatment not only resulted in apoptosis but also induced autophagy. AMPK/mTOR signaling pathway was found to be involved in the activation of autophagy in ORI/Cet-treated LSCC cells, which is independent of p53 status. Additionally, chromatin immunoprecipitation (ChIP) assay showed that ORI/Cet significantly increased the binding NF-κB family member p65 with the promotor of BECN 1, and p65-mediated up-regulation of BECN 1 caused by ORI/Cet is coupled to increased autophagy. On the other hand, we demonstrated that either Beclin 1 SiRNA or autophagy inhibitors could increase ORI/Cet induced-apoptosis, indicating that autophagy induced by combination of the two agents plays a cytoprotective role. Interestingly, 48 h after the combined treatment, autophagy began to decrease but apoptosis was significantly elevated. Our findings suggest that autophagy might be strongly associated with the antitumor efficacy of ORI/Cet, which may be beneficial to the clinical application of ORI/Cet in LSCC treatment.

Oridonin Induces Apoptosis of Laryngeal Carcinoma via Endoplasmic Reticulum Stress

PURPOSE

Oridonin, a bioactive diterpenoid derived from Rabdosia rubescens, has been widely reported to exhibit anticancer activity in multiple types of cancer. However, the molecular mechanism of oridonin in human laryngeal carcinoma has not been clearly elucidated. This study investigated the function of oridonin in laryngeal carcinoma to provide a research basis for laryngeal carcinoma therapy.

METHODS

The proliferation of laryngeal carcinoma Hep-2 and TU212 cells treated with oridonin was determined by MTT assay. The apoptotic induction effect of oridonin on Hep-2 and TU212 cells was analyzed by flow cytometry, Western blot analysis and caspase3 activity assay. In addition, the caspase inhibitor, Z-VAD-fmk, was synergistically treated with oridonin to detect the function of caspase cascade in oridonin-mediated apoptosis. Then, the expressions of endoplasmic reticulum (ER) stress-related proteins (GRP78, phosphorylated-PERK, phosphorylated-eIF2α and CHOP) were measured in Hep-2 and TU212 cells by Western blotting. The cells were treated with 4-PBA (an ER stress inhibitor) or knockdown of CHOP to explore the role of ER stress in oridonin-mediated apoptosis in laryngeal carcinoma. Subsequently, a nude mouse xenograft model was constructed to confirm the function of oridonin in laryngeal carcinoma in vivo.

RESULTS

Oridonin was found to significantly inhibit the proliferation of laryngeal carcinoma Hep-2 and TU212 cells in a concentration-dependent manner. Then, we confirmed that oridonin could induce apoptosis in human laryngeal carcinoma cells. The caspase inhibitor, Z-VAD-fmk, could partially reverse the pro-apoptotic effect of oridonin on human laryngeal carcinoma cells. Subsequently, Western blotting analysis demonstrated that endoplasmic reticulum (ER) stress-related proteins (GRP78, phosphorylated-PERK, phosphorylated-eIF2α and CHOP) were up-regulated in Hep-2 and TU212 cells exposed to oridonin. In addition, 4-PBA (an ER stress inhibitor) or knockdown of CHOP could antagonize oridonin-induced apoptosis. Oridonin significantly decreased the tumorigenicity of Hep-2 cells in a nude mouse xenograft model.

CONCLUSION

Oridonin-induced apoptosis of human laryngeal carcinoma through the activation of ER stress.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

MYCT1 represses apoptosis of laryngeal cancerous cells through the MAX/miR-181a/NPM1 pathway

MYCT1 is an important gene known to regulate cell viability and apoptosis of laryngeal cancer cells. However, the underlying molecular mechanism remains unclear. Here, we show that MAX enhances the expression of miR-181a by directly binding to its promoter, whereas miR-181a targets NPM1 and suppresses its expression in laryngeal cancer cells. MYCT1 and miR-181a decrease cell viability and colony formation through enhanced apoptosis, whereas NPM1 displays opposite effects in laryngeal cancer cells. Their opposing functions are further supported by the findings (a) that miR-181a is down-regulated, while NPM1 is up-regulated in laryngeal cancer, and (b) that either inhibition of miR-181a or overexpression of NPM1 can revert the pro-apoptotic effects of MYCT1 on laryngeal cancer cells through extracellular and intracellular apoptotic pathways. Our data suggest that MYCT1 may synergistically interact with MAX as a co-transcription factor or a component of MAX transcriptional complex, to transcriptionally regulate the expression of miR-181a, which, in turn, decreases NPM1 expression at post-transcriptional levels, leading to enhanced apoptosis in laryngeal cancer cells. These factors may serve as potential targets for early diagnosis and treatment of laryngeal cancer.

Recent Development of Oridonin Derivatives with Diverse Pharmacological Activities

Oridonin is one of the major components isolated from Isodon rubescens, a traditional Chinese medicine, and it has been confirmed to exhibit many kinds of biological activities including anticancer, anti-inflammation, antibacterial and so on. However, the poor pharmaceutical property limits the clinical applications of oridonin. So many strategies have been explored in the purpose of improving the potencies of oridonin, and structure modification is one thus way. This review outlines the landscape of the recent development of oridonin derivatives with diverse pharmacological activities, mainly focusing on the biological properties, structure-activity relationships, and mechanism of actions.

Glaucocalyxin B protects against oxygen-glucose-deprivation/reperfusion-induced neuronal injury in PC-12 cells

Oxidative stress has been implicated in the development of cerebral ischemia/reperfusion (I/R) injury. Glaucocalyxin B (GLB), one of five ent-kauranoid diterpenoids, was reported to possess neuroprotective activity. However, the effect of GLB on oxygen-glucose-deprivation/reperfusion (OGD/R)-induced cell injury in PC-12 cells has not been explored. PC-12 cells was treated with various concentrations of GLB (0, 2.5, 5 and 10 μM), and cell viability was detected using the MTT assay. PC-12 cells were pretreated with the indicated concentration of GLB (2.5-10 μM, 2 hours pretreatment), and were maintained under OGD for 3 hours, followed by 24 hours of reoxygenation. Cell viability was assessed using the MTT assay. The levels of superoxide dismutase, malondialdehyde, and glutathione peroxidase were detected using commercially available ELISA Kits. Intracellular reactive oxygen species level was measured using the fluorescent probe 2',7'-dichlorofluorescein diacetate. The levels of Bcl-2, Bax, p-Akt, Akt, p-mTOR, mTOR were detected using Western blot. Our results revealed that GLB significantly protected PC12 cells against OGD/R-induced cell injury. In addition, GLB efficiently inhibited oxidative stress and cell apoptosis in OGD/R-stimulated PC-12 cells. Mechanistic studies revealed that pretreatment with GLB could induce the activation of Akt/mTOR signaling pathway resulting in protection of OGD-treated PC12 cells. In conclusion, our data indicate for the first time that GLB protects against OGD/R-induced neuronal injury in PC-12 cells. The mechanism of the protective effect of GLB is partially associated with activation of the Akt/mTOR signaling pathway. Thus, GLB may be a potential agent for protection against cerebral I/R injury.

Oridonin enhances the radiosensitivity of lung cancer cells by upregulating Bax and downregulating Bcl-2

Oridonin is an active component of the traditional Chinese herb Rabdosia rubescens. The present study aimed to evaluate the antitumor effects of oridonin on human non-small cell lung cancer (NSCLC) cells and explore whether oridonin could enhance their radiosensitivity. Oridonin was demonstrated to inhibit the proliferation of SPC-A-1 and HCC827 lung cancer cells in a time- and dose-dependent manner, which was detected using the MTT assay. In addition, pretreatment with oridonin for 24 h prior to irradiation was identified to enhance the radiosensitivity of SPC-A-1 cells. Furthermore, the levels of apoptosis regulator BAX (Bax) and apoptosis regulator Bcl-2 (Bcl-2) were detected by western blotting analysis. The results demonstrated that the level of Bax was increased and the level of Bcl-2 was decreased in SPC-A-1 cells treated with oridonin and irradiation compared with the group that received irradiation alone. These results indicate that oridonin may have a novel application as a radiosensitizing agent for the treatment of human NSCLC.

Natural Diterpenoid Isoferritin A (IsoA) Inhibits Glioma Cell Growth and Metastasis via Regulating of TGFβ-Induced EMT Signal Pathway

Background

Malignant glioma is intractable primary brain carcinoma that has a poor survival rate. Natural diterpenoid isoferritin A (IsoA) presents antitumor effects by regulating signal pathways in tumor cells. In the present study we investigated the inhibitory effects of IsoA on glioma cells.

Material/Methods

The potential molecular mechanism of IsoA-mediated glioma cell growth and metastasis were investigated using Western blot, gene knockdown, immunofluorescence, and immunohistochemistry.

Results

Results showed that IsoA significantly inhibits growth and metastasis of glioma cells in multiple preclinical settings. In vitro assay showed that IsoA (4 mg/ml) treatment significantly induced apoptosis of glioma cells. Mechanism analysis demonstrated that IsoA (4 mg/ml) treatment decreased TGFβ and regulated EMT markers expression in glioma cells. Reduced expression of TGFβ in glioma cells was closely correlated with inhibitory effects of IsoA on growth and metastasis of glioma cells. TGFβ overexpression promoted glioma cell growth and invasion. Results also showed that IsoA treatment significantly decreased Fibronectin and Vimentin and increased E-cadherin, while TGFβ overexpression abolished the regulation mediated by IsoA in glioma cells. In vivo assay showed that IsoA treatment inhibited tumor growth in a glioma-bearing mouse model.

Conclusions

Results indicate that IsoA could be regarded as a potential anti-cancer agent by regulating TGFβ-induced EMT signal pathway.

Synergistic Antitumour Properties of viscumTT in Alveolar Rhabdomyosarcoma

Aqueous mistletoe extracts from the European mistletoe (Viscum album) contain mainly mistletoe lectins and viscotoxins as cytotoxic compounds. Lipophilic triterpene acids, which do not occur in conventional mistletoe preparations, were solubilised with β-cyclodextrins. The combination of an aqueous extract (viscum) and a triterpene-containing extract (TT) recreated a whole mistletoe extract (viscumTT). These extracts were tested on rhabdomyosarcoma in vitro, ex vivo, and in vivo with regard to anticancer effects. Viscum and viscumTT inhibited cell proliferation and induced apoptosis effectively in a dose-dependent manner in vitro and ex vivo, whereas TT showed only moderate inhibitory effects. viscumTT proved to be more effective than the single extracts and displayed a synergistic effect in vitro and a stronger effect in vivo. viscumTT induced apoptosis via the extrinsic and intrinsic pathways, evidenced by the loss of mitochondrial membrane potential and activation of CASP8 and CASP9. CASP10 inhibitor inhibited apoptosis effectively, emphasising the importance of CASP10 in viscumTT-induced apoptosis. Additionally, viscumTT changed the ratio of apoptosis-associated proteins by downregulation of antiapoptotic proteins such as XIAP and BIRC5, thus shifting the balance towards apoptosis. viscumTT effectively reduced tumour volume in patient-derived xenografts in vivo and may be considered a promising substance for rhabdomyosarcoma therapy.

Diterpenes and Their Derivatives as Potential Anticancer Agents

As therapeutic tools, diterpenes and their derivatives have gained much attention of the medicinal scientists nowadays. It is due to their pledging and important biological activities. This review congregates the anticancer diterpenes. For this, a search was made with selected keywords in PubMed, Science Direct, Web of Science, Scopus, The American Chemical Society and miscellaneous databases from January 2012 to January 2017 for the published articles. A total 28, 789 published articles were seen. Among them, 240 were included in this study. More than 250 important anticancer diterpenes and their derivatives were seen in the databases, acting in the different pathways. Some of them are already under clinical trials, while others are in the nonclinical and/or pre-clinical trials. In conclusion, diterpenes may be one of the lead molecules in the treatment of cancer. Copyright © 2017 John Wiley & Sons, Ltd.

Mycobacterium avium MAV2054 protein induces macrophage apoptosis by targeting mitochondria and reduces intracellular bacterial growth

Mycobacterium avium complex induces macrophage apoptosis. However, the M. avium components that inhibit or trigger apoptosis and their regulating mechanisms remain unclear. We recently identified the immunodominant MAV2054 protein by fractionating M. avium culture filtrate protein by multistep chromatography; this protein showed strong immuno-reactivity in M. avium complex pulmonary disease and in patients with tuberculosis. Here, we investigated the biological effects of MAV2054 on murine macrophages. Recombinant MAV2054 induced caspase-dependent macrophage apoptosis. Enhanced reactive oxygen species production and JNK activation were essential for MAV2054-mediated apoptosis and MAV2054-induced interleukin-6, tumour necrosis factor, and monocyte chemoattractant protein-1 production. MAV2054 was targeted to the mitochondrial compartment of macrophages treated with MAV2054 and infected with M. avium. Dissipation of the mitochondrial transmembrane potential (ΔΨ_m) and depletion of cytochrome c also occurred in MAV2054-treated macrophages. Apoptotic response, reactive oxygen species production, and ΔΨ_m collapse were significantly increased in bone marrow-derived macrophages infected with Mycobacterium smegmatis expressing MAV2054, compared to that in M. smegmatis control. Furthermore, MAV2054 expression suppressed intracellular growth of M. smegmatis and increased the survival rate of M. smegmatis-infected mice. Thus, MAV2054 induces apoptosis via a mitochondrial pathway in macrophages, which may be an innate cellular response to limit intracellular M. avium multiplication.

JD enhances the anti-tumour effects of low-dose paclitaxel on gastric cancer MKN45 cells both in vitro and in vivo

BACKGROUND

Gastric cancer is the third most common cause of cancer mortality worldwide, and paclitaxel (PTX) is one of the most widely used traditional drugs in gastric cancer therapy. However, the response to traditional therapy is limited by acquired chemo-resistance and side effects. Here, we establish a newly designed combination therapy consisting of a compound that is a structural variant of oridonin, i.e. Jesridonin (JD), and low-dose PTX for gastric cancer cells (MKN45) to investigate whether the anti-tumour activity of low-dose PTX could be enhanced when combined with JD.

METHODS

The interaction of JD and low-dose PTX was detected in MKN45 cells using the median-effect analysis method. The synergistic effect on cell viability and apoptosis was measured by MTT assay, colony formation assay, transient transfection, flow cytometry and Western blotting. The synergistic in vivo effect of JD plus low-dose PTX was evaluated in nude mouse xenograft models using H&E and TUNEL staining and Western blotting.

RESULTS

JD plus low-dose PTX showed a synergistic effect, as the combination indexes were less than 1. Additionally, a synergistic anti-proliferative and pro-apoptotic effect was detected for the combination of JD and low-dose PTX. The apoptotic mechanism induced by JD plus PTX revealed that the combination therapy synergistically activated the mitochondrial pathway.

CONCLUSION

Our findings suggest that JD enhances the anti-tumour effect of low-dose PTX on gastric carcinoma cancer cells in both vitro and in vivo, accompanied by activation of the mitochondrial pathway, which may present a more effective therapeutic strategy in gastric cancer treatment.

The inhibitory effects of carnosic acid on cervical cancer cells growth by promoting apoptosis via ROS-regulated signaling pathway

Cervical cancer has been the fourth most common cancer killing many women across the world. Carnosic acid (CA), as a phenolic diterpene, has been suggested to against cancer, exerting protective effects associated with inflammatory cytokines. It is aimed to demonstrate the therapeutic role of carnosic acid against cervical cancer and indicate its underlying molecular mechanisms. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) was performed to assess the possible anti-proliferative effects of carnosic acid. And also, colony formation was used to further estimate carnosic acid's ability in suppressing cervical cancer cells proliferation. Flow cytometry assays were performed here to indicate the alterations of cervical cancer cells cycle and the development of apoptosis. Western blot assays and RT-PCR were also applied to clarify the apoptosis-associated signaling pathways affected by reactive oxygen species (ROS) generation. And immunofluorescence was used to detect ROS-positive cells. In vivo experiments, CaSki xenograft model samples of nude mice were involved to further elucidate the effects of carnosic acid. In our results, we found that carnosic acid exerted anti-tumor ability in vitro supported by up-regulation of apoptosis and ROS production in cervical cancer cells. Also, acceleration of ROS led to the phospharylation of (c-Jun N-terminal kinase (JNK) and its-related signals, as well as activation of Endoplasmic Reticulum (ER) stress, promoting the progression of apoptosis via stimulating Caspase3 expression. The development and growth of xenograft tumors in nude mice were found to be inhibited by the administration of carnosic acid for five weeks. And the suppressed role of carnosic acid in proliferation of cervical cancer cells and apoptosis of nude mice with tumor tissues were observed in our study. Taken together, our data indicated that carnosic acid resulted in apoptosis both in vitro and vivo experiments via promoting ROS and activating JNK signaling pathways in human cervical cancer cells, which supplied a potential therapy for the application of carnosic acid in clinical treatment.

Oridonin induces apoptosis through the mitochondrial pathway in human gastric cancer SGC-7901 cells

Oridonin is one of the most important antitumor active ingredients of Rabdosia rubescens. Recently published studies from our laboratory have demonstrated that oridonin was able to arrest human gastric cancer SGC-7901 cells at G2/M phase. However, little is known about inducing apoptosis in gastric cancer. The aim of this study was to investigate the effect of oridonin on antineoplastic capability of SGC-7901 cells and the detailed molecular mechanism of oridonin-mediated intrinsic pathway of apoptosis. Cell proliferation was assessed by MTT assay while apoptosis induced by oridonin was determined by Hoechst 33342 staining assay and Annexin V/PI double staining assay. Early apoptotic rate was stained by Annexin V/PI and detected by flow cytometry. Apoptosis pathway was analyzed by western blot analysis of Bcl-2, Bax, cytochrome c and caspase-3 expression. The results showed that oridonin was able to inhibit the SGC-7901 cell proliferation, the 50% growth inhibition (IC50) was 22.74 µM. Oridonin could induce cell apoptosis of SGC-7901 cells and the early apoptotic rates induced by 0, 20, 40, 80 µmol/l oridonin were 1.53±0.67, 3.33±0.29, 84.80±0.82 and 96.43±0.51%, respectively. Western blot analysis revealed that oridonin downregulated Bcl-2 protein (the anti-apoptotic factor) and upregulated Bax protein (pro-apoptotic factor), eventually leading to a reduction in the ratio of Bcl-2/Bax proteins. Furthermore, oridonin induced the release of cytochrome c from the mitochondria to the cytosol and the activation of caspase-3. Taken together, the current study suggested that oridonin induced apoptosis in SGC-7901 cells via the mitochondrial signal pathway, which may represent one of the major mechanisms of oridonin-mediated apoptosis in SGC-7901 cells.