Emodin mitigates the oxidative stress induced by cisplatin in osteosarcoma MG63 cells

Effect of traditional Chinese medicine in osteosarcoma: Cross-interference of signaling pathways and potential therapeutic targets

Osteosarcoma (OS) has a high recurrence rate, disability rate, mortality and metastasis, it brings great economic burden and psychological pressure to patients, and then seriously affects the quality of life of patients. At present, the treatment methods of OS mainly include radiotherapy, chemotherapy, surgical therapy and neoadjuvant chemotherapy combined with limb salvage surgery. These treatment methods can relieve the clinical symptoms of patients to a certain extent, and also effectively reduce the disability rate, mortality and recurrence rate of OS patients. However, because metastasis of tumor cells leads to new complications, and OS cells become resistant with prolonged drug intervention, which reduces the sensitivity of OS cells to drugs, these treatments still have some limitations. More and more studies have shown that traditional Chinese medicine (TCM) has the characteristics of "multiple targets and multiple pathways," and can play an important role in the development of OS through several key signaling pathways, including PI3K/AKT, Wnt/β-catenin, tyrosine kinase/transcription factor 3 (JAK/STAT3), Notch, transforming growth factor-β (TGF-β)/Smad, nuclear transcription factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), nuclear factor E2-related factor 2 (Nrf2), Hippo/YAP, OPG/RANK/RANKL, Hedgehog and so on. In this paper, the signaling pathways of cross-interference between active ingredients of TCM and OS were reviewed, and the development status of novel OS treatment was analyzed. The active ingredients in TCM can provide therapeutic benefits to patients by targeting the activity of signaling pathways. In addition, potential strategies for targeted therapy of OS by using ferroptosis were discussed. We hope to provide a unique insight for the in-depth research and clinical application of TCM in the fields of OS growth, metastasis and chemotherapy resistance by understanding the signaling crosstalk between active ingredients in TCM and OS.

Emodin protects against apoptosis and inflammation by regulating reactive oxygen species-mediated NF-κB signaling in interleukin-1β-stimulated human nucleus pulposus cells

Intervertebral disc degeneration (IDD) is a complex degradative disorder associated with inflammation. Emodin, an anthraquinone derivative, possesses strong anti-inflammatory activity. This study focused on the in vitro therapeutic action of emodin in a cellular model of IDD. Human nucleus pulposus cells (NPCs) were stimulated with interleukin-1β (IL-1β) to induce inflammation. Cell Counting Kit-8 and terminal deoxynucleotidyl transferase dUTP nick end labeling staining assays were performed to evaluate the viability and apoptosis of NPCs, respectively. Caspase-3 activity was measured to indirectly assess cell apoptosis. Western blot analysis was performed to detect protein expression levels. Reverse transcription-polymerase chain reaction was performed for the detection of relative mRNA levels of tumor necrosis factor-α (TNF-α) and IL-6. Enzyme-linked immunosorbent assay was performed to analyze TNF-α and IL-6 secretion. Our results showed that emodin treatment mitigated IL-1β-induced reduction of cell viability in NPCs. Moreover, the increase in reactive oxygen species (ROS) production, apoptotic rate, and caspase-3 activity in IL-1β-stimulated NPCs was reduced by emodin treatment. Treatment with emodin also abolished IL-1β-induced inflammation in NPCs, as indicated by reduced secretion of IL-6 and TNF-α. Besides, the increase in expression levels of phosphorylated p65 and nuclear p65 in IL-1β-stimulated NPCs was suppressed by emodin treatment. Furthermore, inhibition of nuclear factor kappa B (NF-κB) activation with pyrrolidine dithiocarbamate aggravated the protective effects of emodin. These results suggested that emodin protected NPCs against IL-1β-induced apoptosis and inflammation via inhibiting ROS-mediated activation of NF-κB.

Recent advances in the therapeutic potential of emodin for human health

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a bioactive compound, a natural anthraquinone aglycone, present mainly in herbaceous species of the families Fabaceae, Polygonaceae and Rhamnaceae, with a physiological role in protection against abiotic stress in vegetative tissues. Emodin is mainly used in traditional Chinese medicine to treat sore throats, carbuncles, sores, blood stasis, and damp-heat jaundice. Pharmacological research in the last decade has revealed other potential therapeutic applications such as anticancer, neuroprotective, antidiabetic, antioxidant and anti-inflammatory. The present study aimed to summarize recent studies on bioavailability, preclinical pharmacological effects with evidence of molecular mechanisms, clinical trials and clinical pitfalls, respectively the therapeutic limitations of emodin. For this purpose, extensive searches were performed using the PubMed/Medline, Scopus, Google scholar, TRIP database, Springer link, Wiley and SciFinder databases as a search engines. The in vitro and in vivo studies included in this updated review highlighted the signaling pathways and molecular mechanisms of emodin. Because its bioavailability is low, there are limitations in clinical therapeutic use. In conclusion, for an increase in pharmacotherapeutic efficacy, future studies with carrier molecules to the target, thus opening up new therapeutic perspectives.

Exploration of components and mechanisms of Polygoni Multiflori Radix-induced hepatotoxicity using siRNA -mediated CYP3A4 or UGT1A1 knockdown liver cells

ETHNOPHARMACOLOGICAL RELEVANCE

Polygoni Multiflori Radix, the dried root of Polygonum multiflorum Thunb., and its processed products have been used as restoratives for centuries in China. However, the reports of Polygoni Multiflori Radix-induced liver injury (PMR-ILI) have received wide attention in recent years, and the components and mechanism of PMR-ILI are not completely clear yet. Our previous studies found that the PMR-ILI was related to the down-regulation of some drug metabolism enzymes (DME).

AIM OF THE STUDY

To explore the effect of the inhibition of CYP3A4 or UGT1A1 on PMR-ILI, screen the relevant hepatotoxic components and unveil its mechanism.

METHODS

RT-qPCR was used to detect the effects of water extract of Polygoni Multiflori Radix (PMR) and its main components on the mRNA expression of CYP3A4 and UGT1A1 in human hepatic parenchyma cell line L02. High-performance liquid chromatography (HPLC) was employed to detect the content of major components in the PMR. And then, the stable CYP3A4 or UGT1A1 knockdown cells were generated using short hairpin RNAs (shRNA) in L02 and HepaRG cells. Hepatotoxic components were identified by cell viability assay when PMR and its four representative components, 2,3,5,4'-tetrahydroxy stilbene glycoside (TSG), emodin (EM), emodin-8-O-β-D-glucoside (EG), and gallic acid (GA), acted on CYP3A4 or UGT1A1 knockdown cell lines. The PMR-ILI mechanism of oxidative stress injury and apoptosis in L02 and HepaRG cells were detected by flow cytometry. Finally, the network toxicology prediction analysis was employed to excavate the targets of its possible toxic components and the influence on the metabolic pathway.

RESULTS

PMR and EM significantly inhibited the mRNA expression of CYP3A4 and UGT1A1 in L02 cells, while TSG and GA activated the mRNA expression of CYP3A4 and UGT1A1, and EG activated CYP3A4 expression while inhibited UGT1A1 expression. The contents of TSG, EG, EM and GA were 34.93 mg/g, 1.39 mg/g, 0.43 mg/g and 0.44 mg/g, respectively. The CYP3A4 or UGT1A1 knockdown cells were successfully constructed in both L02 and HepaRG cells. Low expression of CYP3A4 or UGT1A1 increased PMR cytotoxicity remarkably. Same as PMR, the toxicity of EM and GA increased in shCYP3A4 and shUGT1A1 cells, which suggested EM and GA may be the main components of hepatotoxicity in PMR. Besides, EM not only inhibited the expression of metabolic enzymes but also reduced the cytotoxicity threshold. EM and GA affected the level of ROS, mitochondrial membrane potential, Ca²⁺ concentration, and dose-dependent induced hepatocyte apoptosis in L02 and HepaRG cells. The network toxicology analysis showed that PMR-ILI was related to drug metabolism-cytochrome P450, glutathione metabolism, and steroid hormone biosynthesis.

CONCLUSION

The inhibition of mRNA expression of CYP3A4 or UGT1A1 enhanced hepatotoxicity of PMR. EM and GA, especially EM, may be the main hepatotoxic components in PMR. The mechanism of PMR, EM and GA induced hepatotoxicity was proved to be related to elevated levels of ROS, mitochondrial membrane potential, Ca²⁺ concentration, and induction of apoptosis in liver cells.

The effect of emodin on melanogenesis through the modulation of ERK and MITF signaling pathway

The aim of this study was to investigate the effect of emodin derived from Polygonum multiflorum on melanin production in B16F1 cells. In this study, emodin did not show antioxidant activity in DPPH radical and reducing power assays. However, it was found that emodin scavenged intracellular H₂O₂. Emodin increased not only tyrosinase activity but also melanin synthesis in vitro. Moreover, emodin enhanced melanin synthesis by increasing the expression level of tyrosinase (TYR), tyrosine related protein (TRP)-1, TRP-2, MITF and SIRT1 proteins in live cells treated with H₂O₂ compared with H₂O₂ treatment group in the analyses of western blot and immunofluorescence. Moreover, emodin suppressed ERK activation by SIRT1 and FOXO1. Thus, emodin promoted melanin synthesis by increasing the expression of TRP-1, TRP-2, tyrosinase through the activation of MITF transcription factor. These findings suggest that emodin could promote melanin production related to anti-hair graying.

Effect of emodin on T cell subsets in NOD mice with NaI‑induced experimental autoimmune thyroiditis

Chronic lymphocytic thyroiditis (CLT), also known as Hashimoto's thyroiditis, is an autoimmune disease in which the thyroid gland is gradually destroyed. To date, only a limited number of agents can effectively suppress thyroiditis development in CLT patients. The aim of the current study was to investigate the protective effect of emodin on experimental autoimmune thyroiditis (EAT) in mice, which is considered an excellent model for CLT. NaI was used to induce the EAT model in non-obese diabetic (NOD) mice. An ELISA method was employed to detect the TgAb level (thyroid inflammation) in the serum of the EAT mice. The T cell subsets in peripheral blood and spleen were detected by flow cytometry. The histopathological study revealed that the thyroid inflammatory cell infiltration was significantly reduced by emodin compared with the model group. In addition, ELISA assays indicated that the NaI-induced serum TgAb upregulation was dramatically revered by emodin. Moreover, the level of serum IFN-γ and the cell populations of CD₃⁺CD₄⁺IL-4⁺, CD₃⁺CD₄⁺ IFN-γ⁺, CD₃⁺CD₈⁺IL-4⁺, CD₃⁺CD₈⁺ IFN-γ⁺ T cells in peripheral blood monocytes and splenic lymphocytes were significantly increased by NaI in the model group compared with in the normal group. Nevertheless, this type of increase was markedly attenuated by emodin. To conclude, the EAT model was successfully established by treating NOD mice with NaI. Emodin indicated an inhibitory effect on the autoimmune response that was significantly different in EAT compared with control mice. Furthermore, the anti-inflammatory action of emodin on EAT mice may be mediated via the inhibition of the secretion of IFN-γ and the cell numbers of CD₃⁺CD₄⁺IL-4⁺, CD₃⁺CD₄⁺ IFN-γ⁺, CD₃⁺CD₈⁺IL-4⁺ and CD₃⁺CD₈⁺ IFN-γ⁺ T cells in the peripheral blood monocytes and splenic lymphocytes. Therefore, the data may offer valuable insight on the efficacy of treatment of CLT with emodin.

Integration of bioinformatics and experiments to identify TP53 as a potential target in Emodin inhibiting diffuse large B cell lymphoma

Non-Hodgkin's Lymphoma (NHL) is a group of lymphoid malignancies with unsatisfactory treatment effect in some aggressive subtypes, including diffuse large B cell lymphoma (DLBCL). Emodin is an anthraquinone with potent anti-cancer activities. However, the molecular mechanism of Emodin repressing aggressive NHL remains to be revealed in detail. This study delineated the active mechanism of Emodin action in aggressive NHL by using bioinformatics analysis and in vitro assay. 4 Emodin's primary direct protein targets (DPT) were identified and the DPTs-associated proteins/genes were predicted. Those Emodin-related proteins/genes were subject to enrich Emodin-associated pathways, from which 3 significantly NHL-related signal pathways were refined identified. Advanced integrated analysis exhibited TP53 and PI3K as the significant molecule and pathway by which Emodin may function in NHL. To verify those bioinformatics findings, effects of Emodin and E35, a novel derivative of emodin were investigated on DLBCL cell lines SU-DHL4. Emodin and E35 suppressed proliferation and induced apoptosis of SU-DHL4 cells in a time- and dose-dependent manner. Emodin and E35 declined TP53 protein expression and decreased phosphorylation of PI3K/AKT protein in a dose-dependent manner. All of above showed that combined bioinformatics analysis with experiments offered a novel approach for outlining the mechanisms of Emodin action in DLBCL with convenience and integrity.