Fraxetin Suppresses Cell Proliferation and Induces Apoptosis through Mitochondria Dysfunction in Human Hepatocellular Carcinoma Cell Lines Huh7 and Hep3B

The genus Fraxinus L. (Oleaceae): A review of botany, traditional and modern applications, phytochemistry, and bioactivity

Fraxinus L., a member of the Oleaceae family with approximately 60 species worldwide, is widely distributed in the warm temperate zone of the northern hemisphere. It is not only used as a folk medicine for treating various illnesses but is also documented in medical books. The traditional Chinese medicine "Qin Pi" originated from this genus and is known for its efficacy in treating conditions such as intestinal inflammation, redness and pain in the eyes, abomination of redness and leucorrhoea, and bacterial infections. This paper aims to fill the gap in the existing literature by providing a comprehensive review and critical analysis of the Fraxinus genus plant. The discussion in this paper covers various aspects of the plant, including its botany, traditional and modern applications, phytochemistry, bioactivity, role in ecosystems, phytogenetic evolution, economic benefits, and future challenges. By synthesizing this information, the review aims to offer valuable insights for the advancement, utilization, and further research of the Fraxinus spp.. Phytochemical studies have identified a total of 281 chemical constituents in Fraxinus spp., including secoiridoids, coumarins, and flavonoids. These Fraxinus spp. plants exhibit a wide range of biological activities, such as anti-inflammatory, antioxidant, and antibacterial properties. Furthermore, this paper delves into potential research directions within the genus and addresses the challenges associated with achieving a comprehensive understanding of Fraxinus spp. This paper provides a comprehensive overview of Fraxinus spp., highlighting their bioactivity mechanism and the opportunity to facilitate the advancement of new pharmaceuticals.

The possible anti-tumor actions and mechanisms of active metabolites from Cortex Fraxini

Cortex Fraxini is a traditional Chinese herb that is widely available, inexpensive, and has low toxicity. Modern pharmacological studies have demonstrated that the active metabolites in Cortex Fraxini, including esculin, esculetin, and fraxetin, exert anti-tumor activities by regulating genes and proteins involved in cancer cell proliferation, apoptosis, invasion, and migration. Additionally, these metabolites play a pivotal role in the regulation of several tumor-associated signaling pathways, including the PI3K/Akt, MAPK/ERK, JAK/STAT3, and Wnt/β-catenin pathways. Due to their pro-apoptotic and anti-proliferative properties in vitro and in vivo, Cortex Fraxini and its active metabolites may be considered as potential candidates for the treatment of tumor. The aim of this review is to highlight the anti-tumor biological activities and underlying mechanisms of action of the active metabolites of Cortex Fraxini, with a view to providing a reference for their further development and application in the treatment of tumors.

Exploration of the mechanism of fraxetin in treating acute myeloid leukemia based on network pharmacology and experimental verification

Objective

To explore the pharmacological mechanism of the effect of fraxetin in treating acute myeloid leukemia (AML) by the network pharmacology method combined with experimental validation.

Methods

The targets of fraxetin were identified through Swisstarget prediction, PhammerMap, and CTDBASE. Disease-related targets of AML were explored using GeneCards and DisGenet databases, and the intersected targets were analyzed in the String website to construct a protein-protein interaction (PPI) network. Subsequently, gene ontology (GO) functional enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were conducted using the DAVID database. Molecular docking of core proteins with drugs was performed using Auto Dock Vina software. Finally, the effect of fraxetin on AML was evaluated by in vitro experiments. The effect of fraxetin on AML cell proliferation was assessed by CCK8, the effect of fraxetin on AML cell apoptosis was assessed by flow cytometry, and the expression of relevant protein targets was detected by Western blotting to evaluate the anti-AML effect of fraxetin.

Results

In this study, fraxetin exerts its effect against AML through 101 intersecting genes. The pathway enrichment analysis revealed that the pharmacological effects of fraxetin on AML were related to the Adenosine 5'-monophosphate (AMP)-activated protein kinase （AMPK） signaling pathway, and the molecular docking results indicated that fraxetin had an excellent binding affinity to both the core target and AMPK. In vitro experiments have demonstrated that fraxetin inhibited the proliferation and induced apoptosis of THP1 and HL60 cells, and the western blotting results indicated that the p-AMPK of the fraxetin intervention group was significantly changed in a dose-dependent manner.

Conclusion

Fraxetin may modulate the AMPK signal pathway by interactine with the core target, thereby potentially therapeutic effect on AML.

Health benefits of fraxetin: From chemistry to medicine

Fraxetin is a bioactive molecule present in various natural plants, especially Cortex Fraxini. Evidenced outcomes in phytochemical and biological analyses for this agent are now available in the literature, but an insightful review is yet unknown. The goal of the current research is to offer a panoramic illustration of natural observation, biosynthesis, synthesis, pharmacology, and pharmacokinetics for fraxetin. Esculetin and ferulic acid acted as precursors in the enzymatic biosynthetic route, whereas fraxetin could be easily synthesized from simple phenols. A great deal of interest was obtained in using this molecule for pharmacological targets. Herein, its pharmacological value included anticancer, antioxidative, anti-inflammatory, antidiabetic, antiobesity, and antimicrobial activities, as well as the protection of the liver, neurons, heart, bone, lung, kidney, and others. Anticancer activity may involve the inhibition of proliferation, invasion, and migration, together with apoptotic induction. Health benefits from this molecule were deduced from its ability to suppress cytokines and protect the immune syndrome. Various signaling pathways, such as Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt), nuclear factor kappa B (NF-κB)/NLRP3, Akt/AMPK, have been proposed for in vitro and in vivo mechanisms of action. Fraxetin is highly distributed to rat plasma and several organs. However, more pharmacokinetic studies to improve its bioavailability are needed since its solubility in water is still limited.

Fraxini cortex: Progresses in phytochemistry, pharmacology and ethnomedicinal uses

ETHNOPHARMACOLOGICAL RELEVANCE

Fraxini cortex, which has been widely used as a traditional Chinese medicine for 2000 years, is made from the dried bark of four plant species: Fraxinus chinensis subsp. rhynchophylla (Hance) A.E.Murray, Fraxinus chinensis Roxb., Fraxinus chinensis subsp. chinensis and Fraxinus stylosa Lingelsh.. In Chinese traditional medicine, it possesses the properties of heat-clearing and dampness-drying, asthma relief and cough suppression, as well as vision improvement. It is utilized for treating bacterial disorders, enteritis, leukorrhea, chronic bronitis, painful red eyes with swelling, lacrimation due to windward exposure, psoriasis, and other diseases or related symptoms.

AIM OF THE STUDY

Fraxini cortex is abundant in chemical constituents and has garnered significant attention from plant chemists, particularly regarding coumarins, as evidenced by the recently identified three coumarin compounds. Considering the current dearth of systematic reporting on studies pertaining to Fraxini cortex, herein we provide a comprehensive summary of the advancements in phytochemistry, pharmacology, detection methods, and ethnomedicinal applications of Fraxini cortex.

MATERIALS AND METHODS

We conducted a comprehensive search across online data sources (Web of Science, Public Medicine (PubMed), China National Knowledge Infrastructure (CNKI), as well as Chinese dissertations) and traditional Chinese medicine classics to gather the necessary literature resources for this review.

RESULTS

Briefly, The Fraxini cortex yielded a total of 132 phytochemicals, including coumarins, lignans, secoiridoids, phenylethanol glycosides, flavonoids, triterpenoids, and other compounds. Among them, the main active ingredients are coumarins which possess a diverse range of pharmacological activities such as anti-inflammatory effects, anti-tumor properties, prevention of tissue fibrosis and oxidation damage as well as cardioprotective effects.

CONCLUSIONS

All types of research conducted on Fraxini cortex, particularly in the field of ethnopharmacology, phytochemistry, and pharmacology, have been thoroughly reviewed. However, certain traditional applications and pharmacological activities of Fraxini cortex lack scientific evaluation or convincing evidence due to incomplete methodologies and ambiguous results, as well as a lack of clinical data. To validate its pharmacological activity, clinical efficacy, and safety profile, a systematic and comprehensive research evaluation is imperative. As an important traditional Chinese medicine, Fraxini cortex should be further explored to facilitate the development of novel drugs and therapeutics for various diseases. Greater attention should be given to how it can be better utilized.

Fraxetin pretreatment alleviates cisplatin-induced kidney injury by antagonizing autophagy and apoptosis via mTORC1 activation

Cisplatin-induced kidney injury (CKI) is a common complication of chemotherapy. Fraxetin, derived from Fraxinus bungeana A. DC. bark, has antioxidant, anti-inflammatory, and anti-fibrotic effects. This study aims to investigate fraxetin's effects on CKI and its underlying mechanism in vivo and in vitro. Tubular epithelial cells (TECs) and mice were exposed to cisplatin with and without fraxetin preconditioning assess fraxetin's role in CKI. TECs autophagy was observed using transmission electron microscopy. Apoptosis levels in animal tissues were measured using TUNEL staining. The protective mechanism of fraxetin was explored through pharmacological and genetic regulation of mTORC1. Molecular docking was used to identify potential binding sites between fraxetin and mTORC1. The results indicated that fraxetin pretreatment reduced cisplatin-induced kidney injury in a time- and concentration-dependent way. Fraxetin also decreased autophagy in TECs, as observed through electron microscopy. Tissue staining confirmed that fraxetin pretreatment significantly reduced cisplatin-induced apoptosis. Inhibition of mTORC1 using rapamycin or siRNA reversed the protective effects of fraxetin on apoptosis and autophagy in cisplatin-treated TECs, while activation of mTORC1 enhanced fraxetin's protective effect. Molecular docking analysis revealed that fraxetin can bind to HEAT-repeats binding site on mTORC1 protein. In  summary, fraxetin pretreatment alleviates CKI by antagonizing autophagy and apoptosis via mTORC1 activation. This provides evidence for the potential therapeutic application of fraxetin in CKI.

Fraxetin reduces endometriotic lesions through activation of ER stress, induction of mitochondria-mediated apoptosis, and generation of ROS

BACKGROUND

Fraxetin, a phytochemical obtained from Fraxinus rhynchophylla, is well known for its anti-inflammatory and anti-fibrotic properties. However, fraxetin regulates the progression of endometriosis, which is a benign reproductive disease that results in low quality of life and infertility.

HYPOTHESIS/PURPOSE

We hypothesized that fraxetin may have therapeutic effects on endometriosis and aimed to elucidate the underlying mechanisms of mitochondrial function and tiRNA regulation.

STUDY DESIGN

Endometriotic animal models and cells (End1/E6E7 and VK2/E6E7) were used to identify the mode of action of fraxetin.

METHODS

An auto-implanted endometriosis animal model was established and the effects of fraxetin on lesion size reduction were analyzed. Cell-based assays including proliferation, cell cycle, migration, apoptosis, mitochondrial function, calcium efflux, and reactive oxygen species (ROS) were performed. Moreover, fraxetin signal transduction was demonstrated by western blotting and qPCR analyses.

RESULTS

Fraxetin inhibited proliferation and migration by inactivating the P38/JNK/ERK mitogen-activated protein kinase (MAPK) and AKT/S6 pathways. Fraxetin dissipates mitochondrial membrane potential, downregulates oxidative phosphorylation (OXPHOS), and disrupts redox and calcium homeostasis. Moreover, it triggered endoplasmic reticulum stress and intrinsic apoptosis. Furthermore, we elucidated the functional role of tiRNAHisGTG in endometriosis by transfection with its inhibitor. Finally, we established an endometriosis mouse model and verified endometriotic lesion regression and downregulation of adhesion molecules with inflammation.

CONCLUSION

This study suggests that fraxetin is a novel therapeutic agent that targets mitochondria and tiRNAs. This is the first study to demonstrate the mechanisms of tiRNAHisGTG with mitochondrial function and cell fates and can be applied as a non-hormonal method against the progression of endometriosis.

Mechanisms of ferroptosis regulating oxidative stress and energy metabolism in myocardial ischemia-reperfusion injury and a novel perspective of natural plant active ingredients for its treatment

Acute myocardial infarction remains the leading cause of death in humans. Timely restoration of blood perfusion to ischemic myocardium remains the most effective strategy in the treatment of acute myocardial infarction, which can significantly reduce morbidity and mortality. However, after restoration of blood flow and reperfusion, myocardial injury will aggravate and induce apoptosis of cardiomyocytes, a process called myocardial ischemia-reperfusion injury. Studies have shown that the loss and death of cardiomyocytes caused by oxidative stress, iron load, increased lipid peroxidation, inflammation and mitochondrial dysfunction, etc., are involved in myocardial ischemia-reperfusion injury. In recent years, with the in-depth research on the pathology of myocardial ischemia-reperfusion injury, people have gradually realized that there is a new form of cell death in the pathological process of myocardial ischemia-reperfusion injury, namely ferroptosis. A number of studies have found that in the myocardial tissue of patients with acute myocardial infarction, there are pathological changes closely related to ferroptosis, such as iron metabolism disorder, lipid peroxidation, and increased reactive oxygen species free radicals. Natural plant products such as resveratrol, baicalin, cyanidin-3-O-glucoside, naringenin, and astragaloside IV can also exert therapeutic effects by correcting the imbalance of these ferroptosis-related factors and expression levels. Combining with our previous studies, this review summarizes the regulatory mechanism of natural plant products intervening ferroptosis in myocardial ischemia-reperfusion injury in recent years, in order to provide reference information for the development of targeted ferroptosis inhibitor drugs for the treatment of cardiovascular diseases.

Unveiling the antitumor potential of novel N-(substituted-phenyl)-8-methoxycoumarin-3-carboxamides as dual inhibitors of VEGFR2 kinase and cytochrome P450 for targeted treatment of hepatocellular carcinoma

Being the sixth most diagnosed cancer and the fourth leading cause of cancer-related deaths worldwide, liver cancer is considered as a serious disease with a high prevalence and poor prognosis. Current anticancer drugs for liver cancer have drawbacks, such as limited efficacy in later stages of the disease, toxicity to healthy cells, and the potential for drug resistance. There is ample evidence that coumarin-based compounds are potent anticancer agents, with numerous analogues currently being investigated in preclinical and clinical studies. The current study aimed to explore the antitumor potency of a new class of 8-methoxycoumarin-3-carboxamides against liver cancer. Toward this aim, we have designed, synthesized, and characterized a new set of N-(substituted-phenyl)-8-methoxycoumarin-3-carboxamide analogues. The assessment of antitumor activity revealed that the synthesized class of compounds possesses substantial cytotoxicity toward Hep-G2 cells when compared to staurosporine, without significant impact on normal cells. Out of the synthesized compounds, compound 7 demonstrated the most potent cytotoxic effect against Hep-G2 cells with an IC50 of 0.75 µM, which was more potent than the drug staurosporine (IC50 = 8.37 µM). The investigation into the mechanism behind the antiproliferative activity of compound 7 revealed that it interferes with DNA replication and induces DNA damage, leading to cell cycle arrest as demonstrated by a significant decrease in the percentage of cells in the G1 and G2/M phases, along with an increase in the percentage of cells in the S phase. Flow cytometric analysis further revealed that compound 7 has the ability to trigger programmed cell death by inducing necrosis and apoptosis in HepG-2 cells. Further explorations into the mechanism of action demonstrated that compound 7 displays a potent dual-inhibitory activity toward cytochrome P450 and vascular endothelial growth factor receptor-2 (VEGFR-2) proteins, as compared to sorafenib drug. Further, detailed computational studies revealed that compound 7 displays a considerable binding affinity toward the binding cavity of VEGFR2 and CYP450 proteins. Taken together, our findings indicate that the newly synthesized class of compounds, particularly compound 7, could serve as a promising scaffold for the development of highly effective anticancer agents against liver cancer.

In Silico and In Vitro Studies of 4-Hydroxycoumarin-Based Heterocyclic Enamines as Potential Anti-Tumor Agents

The present study reports the one-step synthesis of several 3-formyl-4-hydroxycouramin-derived enamines (4a-4i) in good yields (65-94%). The characterization of the synthesized compounds was carried out via advanced analytical and spectroscopic techniques, such as melting point, electron impact mass spectrometry (EI-MS), 1H-NMR, 13C-NMR, elemental analysis, FTIR, and UV-Visible spectroscopy. The reaction conditions were optimized, and the maximum yield was obtained at 3-4 h of reflux of the reactants, using 2-butanol as a solvent. The potato disc tumor assay was used to assess Agrobacterium tumefaciens-induced tumors to evaluate the anti-tumor activities of compounds (4a-4i), using Vinblastine as a standard drug. The compound 4g showed the lowest IC50 value (1.12 ± 0.2), which is even better than standard Vinblastine (IC50 7.5 ± 0.6). For further insight into their drug actions, an in silico docking of the compounds was also carried out against the CDK-8 protein. The binding energy values of compounds were found to agree with the experimental results. The compounds 4g and 4h showed the best affinities toward protein, with a binding energy value of -6.8 kcal/mol.

Oxyfluorfen induces cell cycle arrest by regulating MAPK, PI3K and autophagy in ruminant immortalized mammary epithelial cells

Oxyfluorfen, a phenoxy phenyl-type herbicide, causes significant damage to ecosystems through chronically effecting invertebrates, fish, and mammals. Considering its adverse effect on ecosystem conservation, it is necessary to investigate its toxic effects on animals. However, the mechanisms of oxyfluorfen toxicity on bovines are not well established. This study investigated the cytotoxic effect of oxyfluorfen on bovine mammary epithelial cells (MAC-T). We conducted several functional experiments to examine the response of MAC-T to oxyfluorfen under various concentrations (0, 1, 2, 5, and 10 ppm). Oxyfluorfen decreased cell viability and increased apoptotic cells by regulating the expression of apoptotic genes and proteins in MAC-T. In addition, oxyfluorfen-treated cells exhibited reduced PCNA expression with a low 3D spheroid formation as compared to that of control cells. Furthermore, oxyfluorfen treatment suppressed cell cycle progression with a decrease in cyclin D1 and cyclin A2 in MAC-T. Next, we performed western blot analysis to verify intercellular signaling changes in oxyfluorfen-treated MAC-T. The phosphor-AKT protein was increased, whereas MAPK signal pathways were decreased. Particularly, the combination of oxyfluorfen with U0126 or SP600125 completely blocked the ERK1/2 and JNK pathways leading to cell viability in MAC-T. Moreover, oxyfluorfen induced inflammatory gene expression and autophagy by increasing phosphorylation of P62 and LC3B in MAC-T. These results demonstrated that oxyfluorfen has cytotoxic effect on MAC-T, implying that the milk production capacity in cows may eventually harm humans.

Effect of LGR4/EGFR signaling on cell growth and cancer stem cell-like characteristics in liver cancer

PURPOSE

Hepatocellular carcinoma (HCC) is the most common primary liver cancer. Leucine-rich repeat containing G-protein-coupled receptors 4 (LGR4) participates in tumor progression, invasion, and metastasis. Our study aimed to investigate the effect of LGR4 with epidermal growth factor receptor (EGFR) in HCC cells.

METHODS

We employed Hep3B and Huh7 cells to conduct our research. Comprehensive biological activities were characterized by CCK8 and transwell assay. Molecular biology techniques were used to determine the expression of proteins. Hep3B was employed to conduct subcutaneous tumor in mice. The tumor growth and the expression levels of proteins were assessed.

RESULTS

LGR4 overexpression could promote the cells proliferation, migration, and invasion ability, while siLGR4 and siEGFR could inhibit cells biological activities. In addition, LGR4 overexpression promoted the expression levels of RSPO2, β-catenin, EGFR and cancer stem cells (CSCs) markers, whereas silence of LGR4 or EGFR could diminish the expression levels of β-catenin and CSCs markers. Furthermore, knockdown of LGR4 or EGFR also inhibited tumor growth and reduced the expression levels of RSPO2, CD133, CD44, Nanog, β-catenin in vivo.

CONCLUSION

Our data suggest that LGR4 /EGFR signaling in HCC leads to induce tumor growth, which then contributes to stem cell characteristics. It maybe a new perspective for the targeted therapy of HCC treatment.

Fraxetin Interacts Additively with Cisplatin and Mitoxantrone, Antagonistically with Docetaxel in Various Human Melanoma Cell Lines-An Isobolographic Analysis

Malignant melanoma is a skin cancer characterized by rapid development, poor prognosis and high mortality. Due to the frequent drug resistance and/or early metastases in melanoma, new therapeutic methods are urgently needed. The study aimed at assessing the cytotoxic and antiproliferative effects of scoparone and fraxetin in vitro, when used alone and in combination with three cytostatics: cisplatin, mitoxantrone, and docetaxel in four human melanoma cell lines. Our experiments showed that scoparone in the concentration range tested up to 200 µM had no significant effect on the viability of human malignant melanoma (therefore, it was not possible to evaluate it in combination with other cytostatics), while fraxetin inhibited cell proliferation with IC₅₀ doses in the range of 32.42-73.16 µM, depending on the cell line. Isobolographic analysis allowed for the assessment of the interactions between the studied compounds. Importantly, fraxetin was not cytotoxic to normal keratinocytes (HaCaT) and melanocytes (HEMa-LP), although it slightly inhibited their viability at high concentrations. The combination of fraxetin with cisplatin and mitoxantrone showed the additive interaction, which seems to be a promising direction in melanoma therapy. Unfortunately, the combination of fraxetin with docetaxel may not be beneficial due to the antagonistic antiproliferative effect of both drugs used in the mixture.

Multi-Omics Analysis Revealed a Significant Alteration of Critical Metabolic Pathways Due to Sorafenib-Resistance in Hep3B Cell Lines

Hepatocellular carcinoma (HCC) is the second prominent cause of cancer-associated death worldwide. Usually, HCC is diagnosed in advanced stages, wherein sorafenib, a multiple target tyrosine kinase inhibitor, is used as the first line of treatment. Unfortunately, resistance to sorafenib is usually encountered within six months of treatment. Therefore, there is a critical need to identify the underlying reasons for drug resistance. In the present study, we investigated the proteomic and metabolomics alterations accompanying sorafenib resistance in hepatocellular carcinoma Hep3B cells by employing ultra-high-performance liquid chromatography quadrupole time of flight mass spectrometry (UHPLC-QTOF-MS). The Bruker Human Metabolome Database (HMDB) library was used to identify the differentially abundant metabolites through MetaboScape 4.0 software (Bruker). For protein annotation and identification, the Uniprot proteome for Homo sapiens (Human) database was utilized through MaxQuant. The results revealed that 27 metabolites and 18 proteins were significantly dysregulated due to sorafenib resistance in Hep3B cells compared to the parental phenotype. D-alanine, L-proline, o-tyrosine, succinic acid and phosphatidylcholine (PC, 16:0/16:0) were among the significantly altered metabolites. Ubiquitin carboxyl-terminal hydrolase isozyme L1, mitochondrial superoxide dismutase, UDP-glucose-6-dehydrogenase, sorbitol dehydrogenase and calpain small subunit 1 were among the significantly altered proteins. The findings revealed that resistant Hep3B cells demonstrated significant alterations in amino acid and nucleotide metabolic pathways, energy production pathways and other pathways related to cancer aggressiveness, such as migration, proliferation and drug-resistance. Joint pathway enrichment analysis unveiled unique pathways, including the antifolate resistance pathway and other important pathways that maintain cancer cells' survival, growth, and proliferation. Collectively, the results identified potential biomarkers for sorafenib-resistant HCC and gave insights into their role in chemotherapeutic drug resistance, cancer initiation, progression and aggressiveness, which may contribute to better prognosis and chemotherapeutic outcomes.

Alpinumisoflavone Impairs Mitochondrial Respiration via Oxidative Stress and MAPK/PI3K Regulation in Hepatocellular Carcinoma Cells

Alpinumisoflavone is a natural prenylated isoflavonoid extracted from the raw fruit of Cudrania tricuspidata. Several studies have reported the beneficial characteristics of alpinumisoflavone, such as its antioxidant, anti-inflammation, anti-bacterial, osteoprotective, and neuroprotective effects. Alpinumisoflavone also has anti-cancer effects on thyroid, renal, and ovarian cancers, but its therapeutic effects on hepatocellular carcinoma (HCC) have not yet been demonstrated. We investigated the anti-cancer effects of alpinumisoflavone on HCC using human liver cancer cell lines, Hep3B and Huh7. Our results confirmed that alpinumisoflavone inhibited viability and regulated the MAPK/PI3K pathway in Hep3B and Huh7 cells. We also verified that alpinumisoflavone can depolarize the mitochondrial membrane potential and suppress the mitochondrial respiration in HCC cells. Moreover, we confirmed the dysregulation of the mitochondrial complexes I, III, and V involving mitochondrial oxidative phosphorylation at the mRNA level and the accumulation of calcium ions in the mitochondrial matrix. Lastly, we demonstrated that alpinumisoflavone induced mitochondria-mediated apoptosis via regulation of the Bcl-xL and BAK proteins. This study elucidates the anti-cancer effects of alpinumisoflavone on HCC.

A novel cuproptosis-related subtypes and gene signature associates with immunophenotype and predicts prognosis accurately in neuroblastoma

Background

Neuroblastoma (NB) is the most frequent solid tumor in pediatrics, which accounts for roughly 15% of cancer-related mortality in children. NB exhibited genetic, morphologic, and clinical heterogeneity, which limited the efficacy of available therapeutic approaches. Recently, a new term 'cuproptosis' has been used to denote a unique biological process triggered by the action of copper. In this instance, selectively inducing copper death is likely to successfully overcome the limitations of conventional anticancer drugs. However, there is still a gap regarding the role of cuproptosis in cancer, especially in pediatric neuroblastoma.

Methods

We characterized the specific expression of cuproptosis-related genes (CRGs) in NB samples based on publicly available mRNA expression profile data. Consensus clustering and Lasso-Cox regression analysis were applied for CRGs in three independent cohorts. ESTIMATE and Xcell algorithm was utilized to visualize TME score and immune cell subpopulations' relative abundances. Tumor Immune Dysfunction and Exclusion (TIDE) score was used to predict tumor response to immune checkpoint inhibitors. To decipher the underlying mechanism, GSVA was applied to explore enriched pathways associated with cuproptosis signature and Connectivity map (CMap) analysis for drug exploration. Finally, qPCR verified the expression levels of risk-genes in NB cell lines. In addition, PDHA1 was screened and further validated by immunofluorescence in human clinical samples and loss-of-function assays.

Results

We initially classified NB patients according to CRGs and identified two cuproptosis-related subtypes that were associated with prognosis and immunophenotype. After this, a cuproptosis-related prognostic model was constructed and validated by LASSO regression in three independent cohorts. This model can accurately predict prognosis, immune infiltration, and immunotherapy responses. These genes also showed differential expression in various characteristic groups of all three datasets and NB cell lines. Loss-of-function experiments indicated that PDHA1 silencing significantly suppressed the proliferation, migration, and invasion, in turn, promoted cell cycle arrest at the S phase and apoptosis of NB cells.

Conclusions

Taken together, this study may shed light on new research areas for NB patients from the cuproptosis perspective.

Fraxetin down-regulates polo-like kinase 4 (PLK4) to inhibit proliferation, migration and invasion of prostate cancer cells through the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway

Fraxetin, a natural product isolated from herb Cortex Fraxini, has been demonstrated to exhibit anti-cancer effects on various cancers. The aim of this work is to investigate the anti-tumor effect of Fraxetin in prostate cancer and the potential mechanisms. In this study, the prostatic epithelial cell RWPE-1 and prostate cancer cell DU145 were exposed to Fraxetin (10, 20, 40, and 80 μM) to detect the changes in cell viability using cell counting kit-8 (CCK-8) assay. Fraxetin (10, 20, and 40 μM) was utilized to treat DU145 cell, then the changes in cell proliferation, apoptosis, migration, and invasion were assessed. Western blot assay was employed to detect the expression of proteins that participate in the above cellular processes as well as Polo-like kinase 4 (PLK4), phosphatidylinositol 3-kinase (PI3K). In addition to 40 μM Fraxetin treatment, DU145 cells were overexpressed with PLK4, and then the above experiments were repeated. Results revealed that Fraxetin markedly decreased DU145 cell viability, but didn’t affect the cell viability of RWPE-1. Fraxetin suppressed cell proliferation, migration, invasion, and induced apoptosis of DU145 cells in a concentration-dependent manner. Furthermore, the expression of PLK4 and phosphorylated PI3K and protein kinase B (Akt) were reduced upon Fraxetin treatment. Finally, PLK4 overexpression significantly reversed all the effects of Fraxetin on DU145 cells. Collectively, Fraxetin acted as a cancer suppressor in prostate cancer through inhibiting PLK4 expression thereby inactivating PI3K/Akt signaling.

Targeting the mitochondrial permeability transition pore for drug discovery: Challenges and opportunities

Several drug targets have been amenable to drug discovery pursuit not until the characterization of the mitochondrial permeability transition pore (MPTP), a pore with an undefined molecular identity that forms on the inner mitochondrial membrane upon mitochondrial permeability transition (MPT) under the influence of calcium overload and oxidative stress. The opening of the pore which is presumed to cause cell death in certain human diseases also has implications under physiological parlance. Different models for this pore have been postulated following its first identification in the last six decades. The mitochondrial community has witnessed many protein candidates such as; voltage-dependent anion channel (VDAC), adenine nucleotide translocase (ANT), Mitochondrial phosphate carrier (PiC), Spastic Paralegin (SPG7), disordered proteins, and F1Fo ATPase. However, genetic studies have cast out most of these candidates with only F1Fo ATPase currently under intense argument. Cyclophilin D (CyPD) remains the widely accepted positive regulator of the MPTP known to date, but no drug candidate has emerged as its inhibitor, raising concern issues for therapeutics. Thus, in this review, we discuss various models of MPTP reported with the hope of stimulating further research in this field. We went beyond the classical description of the MPTP to ascribe a 'two-edged sword property' to the pore for therapeutic function in human disease because its inhibition and activation have pharmacological relevance. We suggested putative proteins upstream to CyPD that can regulate its activity and prevent cell deaths in neurodegenerative disease and ischemia-reperfusion injury.

Cytotoxicity and Apoptosis Induction of 6,7-Dehydroroyleanone from Taiwania cryptomerioides Bark Essential Oil in Hepatocellular Carcinoma Cells

The objective of the present study is to evaluate the cytotoxicity of Taiwania cryptomerioides essential oil and its phytochemical on the Hep G2 cell line (human hepatocellular carcinoma). Bark essential oil has significant cytotoxicity to Hep G2 cells, and S3 fraction is the most active fraction in cytotoxicity to Hep G2 cells among the six fractions. The diterpenoid quinone, 6,7-dehydroroyleanone, was isolated from the active S3 fraction by bioassay-guided isolation. 6,7-Dehydroroyleanone exhibited significant cytotoxicity in Hep G2 cells, and the efficacy of 6,7-dehydroroyleanone was better than the positive control, etoposide. Apoptosis analysis of Hep G2 cells with different treatments was characterized via flow cytometry to confirm the cell death situation. Etoposide and 6,7-dehydroroyleanone could induce the apoptosis in Hep G2 cells using flow cytometric assay. Results revealed 6,7-dehydroroyleanone from T. cryptomerioides bark essential oil can be a potential phytochemical to develop the anticancer chemotherapeutic agent for the treatment of the human hepatocellular carcinoma.

Antimicrobial peptide 17BIPHE2 inhibits the proliferation of lung cancer cells in vitro and in vivo by regulating the ERK signaling pathway

In 2018, there were 18.1 million new cancer cases and 9.6 million cancer-related deaths worldwide, among which the incidence rate of lung cancer (11.6%) and fatality rate (18.4%) both ranked first. The antimicrobial peptide LL-37 is an important component of the natural immune system and possesses several biological properties, including antibacterial, antiviral and anticancer effects. The antimicrobial peptide 17BIPHE2, the shortest synthetic peptide derivative of LL-37, exhibits biological activities similar to those of LL-37. The objective of the present study was to investigate the mechanism of action of exogenous 17BIPHE2 against lung cancer cells. The human lung adenocarcinoma cell line A549 was treated with 17BIPHE2. Changes in cell proliferation, migration, invasion, mitochondrial membrane potential (ΔΨm), and the levels of reactive oxygen species (ROS), Ca2+ and apoptosis-related proteins, including BAX, BCL-2 and ERK, were detected using flow cytometry, transmission electron microscopy and western blotting. The results showed that 17BIPHE2 significantly increased the apoptosis rate of A549 cells and elevated BAX expression, ERK phosphorylation, and ROS and Ca2+ levels, but decreased the expression of BCL-2, ERK and Ki67. In addition, the peptide reduced ΔΨm and the cell migration ability of A549 cells and inhibited tumor growth. ERK inhibition significantly attenuated the anticancer effect of 17BIPHE2. The present observations suggested that 17BIPHE2 can effectively inhibit cancer cells by regulating the ERK signaling pathway.