Alkannin induces cytotoxic autophagy and apoptosis by promoting ROS-mediated mitochondrial dysfunction and activation of JNK pathway

Targeted degradation of NDUFS1 by agrimol B promotes mitochondrial ROS accumulation and cytotoxic autophagy arrest in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a global public health problem with increased morbidity and mortality. Agrimol B, a natural polyphenol, has been proved to be a potential anticancer drug. Our recent report showed a favorable anticancer effect of agrimol B in HCC, however, the mechanism of action remains unclear. Here, we found agrimol B inhibits the growth and proliferation of HCC cells in vitro as well as in an HCC patient-derived xenograft (PDX) model. Notably, agrimol B drives autophagy initiation and blocks autophagosome-lysosome fusion, resulting in autophagosome accumulation and autophagy arrest in HCC cells. Mechanistically, agrimol B downregulates the protein level of NADH:ubiquinone oxidoreductase core subunit S1 (NDUFS1) through caspase 3-mediated degradation, leading to mitochondrial reactive oxygen species (mROS) accumulation and autophagy arrest. NDUFS1 overexpression partially restores mROS overproduction, autophagosome accumulation, and growth inhibition induced by agrimol B, suggesting a cytotoxic role of agrimol B-induced autophagy arrest in HCC cells. Notably, agrimol B significantly enhances the sensitivity of HCC cells to sorafenib in vitro and in vivo. In conclusion, our study uncovers the anticancer mechanism of agrimol B in HCC involving the regulation of oxidative stress and autophagy, and suggests agrimol B as a potential therapeutic drug for HCC treatment.

DDX39B protects against sorafenib-induced ferroptosis by facilitating the splicing and cytoplasmic export of GPX4 pre-mRNA in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the main histological subtype of primary liver cancer and remains one of the most common solid malignancies globally. Ferroptosis was recently defined as an iron-catalyzed form of regulated necrosis. Because cancer cells exhibit higher iron requirements than noncancer cells, treatment with ferroptosis-inducing compounds may be a feasible strategy for cancer therapy. However, cancer cells develop acquired resistance to evade ferroptosis, and the mechanisms responsible for ferroptosis resistance are not fully clarified. In the current study, we reported that DDX39B was downregulated during sorafenib-induced ferroptosis in a dose- and time-dependent manner. Exogenous introduction of DDX39B ensured the survival of HCC cells upon exposure to sorafenib, while the opposite phenomenon was observed in DDX39B-silenced HCC cells. Mechanistically, we demonstrated that DDX39B increased GPX4 levels by promoting the splicing and cytoplasmic translocation of GPX4 pre-mRNA, which was sufficient to detoxify sorafenib-triggered excess lipid ROS production, lipid peroxidation accumulation, ferrous iron levels, and mitochondrial damage. Inhibition of DDX39B ATPase activity by CCT018159 repressed the splicing and cytoplasmic export of GPX4 pre-mRNA and synergistically assisted sorafenib-induced ferroptotic cell death in HCC cells. Taken together, our data uncover a novel role for DDX39B in ferroptosis resistance by modulating the maturation of GPX4 mRNA via a posttranscriptional approach and suggest that DDX39B inhibition may be a promising therapeutic strategy to enhance the sensitivity and vulnerability of HCC cells to sorafenib.

Shengjihuayu formula ameliorates the oxidative injury in human keratinocytes via blocking JNK/c-Jun/MMPs signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The reactive oxygen species (ROS) surge in the chronic wound tissue of diabetic ulcers (DUs) aggravates the inflammatory response. The oxidative stress state during inflammation will exacerbate inflammation and cause tissue damage, resulting in prolonged wound healing. Shengjihuayu Formula (SJHYF) is a renowned Chinese medicine prescription for treating chronic wounds in diabetic ulcers. Growing clinical evidence has demonstrated that SJHYF exhibits superior therapeutic efficacy and has a favorable safety profile. However, the underlying mechanisms by which SJHYF ameliorates oxidative damage under pathological conditions of DUs remain unclear.

OBJECTIVE

To investigate the cytoprotective properties of SJHYF on hydrogen peroxide (H2O2)-induced cell damage in human HaCaT keratinocytes and to explore its potential targets and molecular pathways in treating DUs using RNA-seq.

METHODS

HaCaT cells were incubated with H2O2 for 24 h to construct an oxidative stress cell model. Cell viability and proliferation were measured using the MTT and EdU assays, respectively. Cell migration was assessed using the scratch assay, and the fluorescence intensity of ROS was measured using the DCFH-DA probe. The chemical components of SJHYF were analyzed by UPLC-Q-TOF/MS, while the therapeutic effects of SJHYF on H2O2-induced HaCaT cells were analyzed using RNA-Seq. The potential target genes were validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). At the same time, the pathway phenotype expression of SJHYF on the protection of H2O2-induced HaCaT cells was explored using Western Blot.

RESULTS

The application of SJHY at a concentration of 0.25 mg/mL promoted cell proliferation, cell migration, and reduced ROS production. In addition, SJHYF was detected to have a total of 93 active compounds, including key components such as Galloyl-beta-D-glucose, Danshensu, Procyanidin B2, Catechin, and Alkannin. The RNA-seq analysis identified several core targets namely KRT17, TGM1, JUNB, PRDX5, TXNIP, PRDX1, HSP90AA1, HSP90AB1, HSPA8, and TNF-α. Western blot revealed the presence of the JNK/c-Jun/MMPs pathway and its related transcription factors.

CONCLUSION

SJHYF displays significant protective effects on H2O2-induced oxidative cell damage in HaCaT cells via blocking the JNK/c-Jun/MMPs pathway.

Unlocking the potential of 1,4-naphthoquinones: A comprehensive review of their anticancer properties

Cancer encompasses a group of pathologies with common characteristics, high incidence, and prevalence in all countries. Although there are treatments available for this disease, they are not always effective or safe, often failing to achieve the desired results. This is why it is necessary to continue the search for new therapies. One of the strategies for obtaining new antitumor drugs is the use of 1,4-naphthoquinone as a scaffold in synthetic or natural products with antitumor activity. This review focuses on compiling studies related to the antitumor activity of 1,4-naphthoquinone and its natural and synthetic derivatives over the last 10 years. The work describes the main natural naphthoquinones with antitumor activity and classifies the synthetic naphthoquinones based on the structural modifications made to the scaffold. Additionally, the formation of metal complexes using naphthoquinones as a ligand is considered. After a thorough review, 197 synthetic compounds with potent biological activity against cancer have been classified according to their chemical structures and their mechanisms of action have been described.

Exploiting Nanotechnology for Drug Delivery: Advancing the Anti-Cancer Effects of Autophagy-Modulating Compounds in Traditional Chinese Medicine

Background

Cancer continues to be a prominent issue in the field of medicine, as demonstrated by recent studies emphasizing the significant role of autophagy in the development of cancer. Traditional Chinese Medicine (TCM) provides a variety of anti-tumor agents capable of regulating autophagy. However, the clinical application of autophagy-modulating compounds derived from TCM is impeded by their restricted water solubility and bioavailability. To overcome this challenge, the utilization of nanotechnology has been suggested as a potential solution. Nonetheless, the current body of literature on nanoparticles delivering TCM-derived autophagy-modulating anti-tumor compounds for cancer treatment is limited, lacking comprehensive summaries and detailed descriptions.

Methods

Up to November 2023, a comprehensive research study was conducted to gather relevant data using a variety of databases, including PubMed, ScienceDirect, Springer Link, Web of Science, and CNKI. The keywords utilized in this investigation included "autophagy", "nanoparticles", "traditional Chinese medicine" and "anticancer".

Results

This review provides a comprehensive analysis of the potential of nanotechnology in overcoming delivery challenges and enhancing the anti-cancer properties of autophagy-modulating compounds in TCM. The evaluation is based on a synthesis of different classes of autophagy-modulating compounds in TCM, their mechanisms of action in cancer treatment, and their potential benefits as reported in various scholarly sources. The findings indicate that nanotechnology shows potential in enhancing the availability of autophagy-modulating agents in TCM, thereby opening up a plethora of potential therapeutic avenues.

Conclusion

Nanotechnology has the potential to enhance the anti-tumor efficacy of autophagy-modulating compounds in traditional TCM, through regulation of autophagy.

Shikonin and Alkannin inhibit ATP synthase and impede the cell growth in Escherichia coli

Naturally occurring naphthoquinones, shikonin and alkannin, are important ingredients of traditional Chinese medicine Zicao. These constituents are reported to have many therapeutic uses, such as wound healing; scar treatment; and anti-inflammation, anti-acne, anti-ulcer, anti-HIV, anticancer, and antibacterial properties. The primary objective of this investigation was to explore the effect of shikonin and alkannin on Escherichia coli ATP synthase and its cell growth. Shikonin caused complete (100 %) inhibition, and alkannin caused partial (79 %) inhibition of wild-type E. coli ATP synthase. Both caused partial (4 %-27 %) inhibition of ATP synthase with genetically modified phytochemical binding site. The growth inhibition of strains expressing normal, deficient, and mutant ATP synthase by shikonin and alkannin, corroborated the inhibition observed in isolated normal wild-type and mutant ATP synthase. Trivial inhibition of mutant enzymes indicated αR283D, αE284R, βV265Q, and γT273A are essential for formation of the phytochemical binding site where shikonin and alkannin bind. Further, shikonin was a potent inhibitor of ATP synthase than alkannin. The antimicrobial properties of shikonin and alkannin were tied to the binding at phytochemical site of microbial ATP synthase. Selective targeting of bacterial ATP synthase by shikonin and alkannin may be an advantageous alternative to address the antibiotic resistance issue.

JNK regulates the Nrf2/NQO1-ARE pathway against Microcystins-Induced oxidative stress in freshwater mussel Cristaria plicata

In response to stress, cells can utilize several processes, such as the activation of the Nrf2/Keap1 pathway as a critical regulator of oxidative stress to protect against oxidative damage. C-Jun N-terminal kinase (JNK), a member of the mitogen-activated protein kinase (MAPK) family, is involved in regulating the NF-E2-related nuclear factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway. NAD(P)H quinone redox enzyme-1 (NQO1), a downstream target gene of the Nrf2 pathway, plays a vital role in removing peroxide and providing resistance to oxidative injury. We found that microcystins (MCs) stimulated CpNrf2 to express and increase anti-oxidative enzyme activities in a previous experiment. In our current study, the full-length cDNAs of JNK and NQO1 from Cristaria plicata (designated CpJNK and CpNQO1) were cloned. The relative levels of CpJNK and CpNQO1 were high in hepatopancreas. Upon MCs induction, the relative level of CpNQO1 was increased, whereas that of CpJNK was decreased significantly. In contrast, CpNrf2 knockdown upregulated the expression of CpJNK mRNA and phosphorylation of CpJNK protein (Cpp-JNK), but inhibited CpNQO1 expression. Additionally, we found that JNK inhibitor SP600125 stimulated expression of CpNQO1 and CpNrf2 upon exposure to MCs, and we further confirmed that CpNrf2 protein combined with the ARE element in CpNQO1 gene promoter in vitro, and increased CpNQO1-ARE-luciferase activity in a CpNrf2-dependent manner. These findings indicated C. plicata effectively alleviated MC-induced oxidative injury through JNK participated in regulating the Nrf2/NQO1-ARE pathway.

Aging, oxidative stress and degenerative diseases: mechanisms, complications and emerging therapeutic strategies

Aging accompanied by several age-related complications, is a multifaceted inevitable biological progression involving various genetic, environmental, and lifestyle factors. The major factor in this process is oxidative stress, caused by an abundance of reactive oxygen species (ROS) generated in the mitochondria and endoplasmic reticulum (ER). ROS and RNS pose a threat by disrupting signaling mechanisms and causing oxidative damage to cellular components. This oxidative stress affects both the ER and mitochondria, causing proteopathies (abnormal protein aggregation), initiation of unfolded protein response, mitochondrial dysfunction, abnormal cellular senescence, ultimately leading to inflammaging (chronic inflammation associated with aging) and, in rare cases, metastasis. RONS during oxidative stress dysregulate multiple metabolic pathways like NF-κB, MAPK, Nrf-2/Keap-1/ARE and PI3K/Akt which may lead to inappropriate cell death through apoptosis and necrosis. Inflammaging contributes to the development of inflammatory and degenerative diseases such as neurodegenerative diseases, diabetes, cardiovascular disease, chronic kidney disease, and retinopathy. The body's antioxidant systems, sirtuins, autophagy, apoptosis, and biogenesis play a role in maintaining homeostasis, but they have limitations and cannot achieve an ideal state of balance. Certain interventions, such as calorie restriction, intermittent fasting, dietary habits, and regular exercise, have shown beneficial effects in counteracting the aging process. In addition, interventions like senotherapy (targeting senescent cells) and sirtuin-activating compounds (STACs) enhance autophagy and apoptosis for efficient removal of damaged oxidative products and organelles. Further, STACs enhance biogenesis for the regeneration of required organelles to maintain homeostasis. This review article explores the various aspects of oxidative damage, the associated complications, and potential strategies to mitigate these effects.

ZEB1 potentiates chemoresistance in breast cancer stem cells by evading apoptosis

Chemoresistance renders a challenge to the clinics to treat breast cancer patients. Current treatment strategies are effective in mitigating tumor growth but remain largely ineffective against cancer-initiating cells or breast Cancer Stem Cells (CSCs). Epithelial-to-mesenchymal-transition (EMT) regulates breast CSC physiology. Zinc finger E-box binding homeobox 1 (ZEB1) is a key EMT-transcription factor that regulates breast CSC - differentiation and metastasis. However, its potential role in modulating tumor chemoresistance has not yet been fully understood. In-silico analysis revealed a higher ZEB1 expression in breast cancer patients that leads to decreased overall and relapse-free survival. We generated sorted breast CSC with stable ZEB1 overexpression (CD24-/CD44+GFP-ZEB1) and/or silencing (CD24-/CD44+ZEB1 shRNA) as well as breast cancer cells with stable ZEB1 overexpression (CD24+GFP-ZEB1) and/or silencing (CD24+ZEB1 shRNA). An increased colony-forming efficiency and doxorubicin accumulation correlated with decreased promoter activity and expression profile of ABCC1 drug-efflux ABC transporter in CD24-/CD44+GFP-ZEB1. Additionally, CD24-/CD44+GFP-ZEB1 demonstrated doxorubicin-induced higher anti-apoptotic and lower pro-apoptotic protein expressions in the mitochondrial and cytosolic fractions. Chemoresistant CD24-/CD44+GFP-ZEB1 cells depicted 1000-fold higher IC-50 values of doxorubicin and decreased activation of JNK-p38 stress kinase molecular signaling-dependent mammosphere forming efficiency to evade apoptosis. Thus, ZEB1 and its downstream effectors are plausible therapeutic targets for the mitigation of breast cancer chemoresistance in patients.

Anticancer therapeutic effect of ginsenosides through mediating reactive oxygen species

Dysregulation of reactive oxygen species (ROS) production and ROS-regulated pathways in cancer cells leads to abnormal accumulation of reactive oxygen species, displaying a double-edged role in cancer progression, either supporting transformation/proliferation and stimulating tumorigenesis or inducing cell death. Cancer cells can accommodate reactive oxygen species by regulating them at levels that allow the activation of pro-cancer signaling pathways without inducing cell death via modulation of the antioxidant defense system. Therefore, targeting reactive oxygen species is a promising approach for cancer treatment. Ginsenosides, their derivatives, and related drug carriers are well-positioned to modulate multiple signaling pathways by regulating oxidative stress-mediated cellular and molecular targets to induce apoptosis; regulate cell cycle arrest and autophagy, invasion, and metastasis; and enhance the sensitivity of drug-resistant cells to chemotherapeutic agents of different cancers depending on the type, level, and source of reactive oxygen species, and the type and stage of the cancer. Our review focuses on the pro- and anticancer effects of reactive oxygen species, and summarizes the mechanisms and recent advances in different ginsenosides that bring about anticancer effects by targeting reactive oxygen species, providing new ideas for designing further anticancer studies or conducting more preclinical and clinical studies.

Integrative analysis of multi-omics data for discovery of ferroptosis-related gene signature predicting immune activity in neuroblastoma

Immunotherapy for neuroblastoma remains unsatisfactory due to heterogeneity and weak immunogenicity. Exploring powerful signatures for the evaluation of immunotherapy outcomes remain the primary purpose. We constructed a ferroptosis-related gene (FRG) signature by least absolute shrinkage and selection operator and Cox regression, identified 10 independent prognostic FRGs in a training cohort (GSE62564), and then verified them in an external validation cohort (TCGA). Associated with clinical factors, the signature accurately predicts overall survival of 3, 5, and 10 years. An independent prognostic nomogram, which included FRG risk, age, stage of the International Neuroblastoma Staging System, and an MYCN status, was constructed. The area under the curves showed satisfactory prognostic predicting performance. Through bulk RNA-seq and proteomics data, we revealed the relationship between hub genes and the key onco-promoter MYCN gene and then validated the results in MYCN-amplified and MYCN-non-amplified cell lines with qRT-PCR. The FRG signature significantly divided patients into high- and low-risk groups, and the differentially expressed genes between the two groups were enriched in immune actions, autophagy, and carcinogenesis behaviors. The low-risk group embodied higher positive immune component infiltration and a higher expression of immune checkpoints with a more favorable immune cytolytic activity (CYT). We verified the predictive power of this signature with data from melanoma patients undergoing immunotherapy, and the predictive power was satisfactory. Gene mutations were closely related to the signature and prognosis. AURKA and PRKAA2 were revealed to be nodal hub FRGs in the signature, and both were shown to have significantly different expressions between the INSS stage IV and other stages after immunohistochemical validation. With single-cell RNA-seq analysis, we found that genes related to T cells were enriched in TNFA signaling and interferon-γ hallmark. In conclusion, we constructed a ferroptosis-related gene signature that can predict the outcomes and work in evaluating the effects of immunotherapy.

Targeting regulated cell death with plant natural compounds for cancer therapy: A revisited review of apoptosis, autophagy-dependent cell death, and necroptosis

Regulated cell death (RCD) refers to programmed cell death regulated by various protein molecules, such as apoptosis, autophagy-dependent cell death, and necroptosis. Accumulating evidence has recently revealed that RCD subroutines have several links to many types of human cancer; therefore, targeting RCD with pharmacological small-molecule compounds would be a promising therapeutic strategy. Moreover, plant natural compounds, small-molecule compounds synthesized from plant sources, and their derivatives have been widely reported to regulate different RCD subroutines to improve potential cancer therapy. Thus, in this review, we focus on updating the intricate mechanisms of apoptosis, autophagy-dependent cell death, and necroptosis in cancer. Moreover, we further discuss several representative plant natural compounds and their derivatives that regulate the above-mentioned three subroutines of RCD, and their potential as candidate small-molecule drugs for the future cancer treatment.

Molecular mechanisms behind ROS regulation in cancer: A balancing act between augmented tumorigenesis and cell apoptosis

ROS include hydroxyl radicals (HO^.), superoxide (O₂^..), and hydrogen peroxide (H₂O₂). ROS are typically produced under physiological conditions and play crucial roles in living organisms. It is known that ROS, which are created spontaneously by cells through aerobic metabolism in mitochondria, can have either a beneficial or detrimental influence on biological systems. Moderate levels of ROS can cause oxidative damage to proteins, DNA and lipids, which can aid in the pathogenesis of many disorders, including cancer. However, excessive concentrations of ROS can initiate programmed cell death in cancer. Presently, a variety of chemotherapeutic drugs and herbal agents are being investigated to induce ROS-mediated cell death in cancer. Therefore, preserving ROS homeostasis is essential for ensuring normal cell development and survival. On account of a significant association of ROS levels at various concentrations with carcinogenesis in a number of malignancies, further studies are needed to determine the underlying molecular mechanisms and develop the possibilities for intervening in these processes.

Alkannin exerts antitumor properties in cutaneous squamous cell carcinoma by inducing apoptosis and shifting the M1/M2 polarization of tumor-associated macrophages by upregulating PTEN

Cutaneous squamous cell carcinoma (CSCC) is a common cancer in humans and is the second major type of skin cancer that causes death in humans. In this article, we investigated the effects of alkannin on CSCC progression. We revealed that alkannin curbed CSCC cell viability in a dose-dependent manner and accelerated CSCC cell apoptosis. In addition, alkannin expedited macrophage M1 polarization while curbing M2 polarization. Moreover, alkannin elevated phosphatase and tensin homolog (PTEN) abundance in CSCC cells. The results of bioinformatics analysis revealed that alkannin might modulate CSCC via PTEN. Downregulation of PTEN reversed the effects of alkannin on apoptosis of CSCC cells and M1/M2 polarization of macrophages. Alkannin reduced CSCC tumor growth in a mouse xenograft model. In conclusion, alkannin curbed the advancement of CSCC by expediting apoptosis and facilitating M1 polarization of macrophages by upregulating PTEN. These data may offer a therapeutic approach against CSCC.

Chemoselective Synthesis of Mannich Adducts from 1,4-Naphthoquinones and Profile as Autophagic Inducers in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a worldwide public health problem, accounting for approximately 90% of all oral cancers, and is the eighth most common cancer in men. Cisplatin and carboplatin are the main chemotherapy drugs used in the clinic. However, in addition to their serious side effects, such as damage to the nervous system and kidneys, there is also drug resistance. Thus, the development of new drugs becomes of great importance. Naphthoquinones have been described with antitumor activity. Some of them are found in nature, but semi synthesis has been used as strategy to find new chemical entities for the treatment of cancer. In the present study, we promote a multiple component reaction (MCR) among lawsone, arylaldehydes, and benzylamine to produce sixteen chemoselectively derivated Mannich adducts of 1,4-naphthoquinones in good yield (up to 97%). The antitumor activities and molecular mechanisms of action of these compounds were investigated in OSCC models and the compound 6a induced cytotoxicity in three different tumor cell lines (OSCC4, OSCC9, and OSCC25) and was more selective (IS > 2) for tumor cells than the chemotropic drug carboplatin and the controls lapachol and shikonin, which are chemically similar compounds with cytotoxic effects. The 6a selectively and significantly reduced the amount of cell colony growth, was not hemolytic, and tolerable in mice with no serious side effects at a concentration of 100 mg/kg with a LD50 of 150 mg/kg. The new compound is biologically stable with a profile similar to carboplatin. Morphologically, 6a does not induce cell retraction or membrane blebs, but it does induce intense vesicle formation and late emergence of membrane bubbles. Exploring the mechanism of cell death induction, compound 6a does not induce ROS formation, and cell viability was not affected by inhibitors of apoptosis (ZVAD) and necroptosis (necrostatin 1). Autophagy followed by a late apoptosis process appears to be the death-inducing pathway of 6a, as observed by increased viability by the autophagy inhibitor (3-MA) and by the appearance of autophagosomes, later triggering a process of late apoptosis with the presence of caspase 3/7 and DNA fragmentation. Molecular modeling suggests the ability of the compound to bind to topoisomerase I and II and with greater affinity to hPKM2 enzyme than controls, which could explain the mechanism of cell death by autophagy. Finally, the in-silico prediction of drug-relevant properties showed that compound 6a has a good pharmacokinetic profile when compared to carboplatin and doxorubicin. Among the sixteen naphthoquinones tested, compound 6a was the most effective and is highly selective and well tolerated in animals. The induction of cell death in OSCC through autophagy followed by late apoptosis possibly via inhibition of the PKM2 enzyme points to a promising potential of 6a as a new preclinical anticancer candidate.

Natural Products as Anticancer Agents: Current Status and Future Perspectives

Natural products have been an invaluable and useful source of anticancer agents over the years. Several compounds have been synthesized from natural products by modifying their structures or by using naturally occurring compounds as building blocks in the synthesis of these compounds for various purposes in different fields, such as biology, medicine, and engineering. Multiple modern and costly treatments have been applied to combat cancer and limit its lethality, but the results are not significantly refreshing. Natural products, which are a significant source of new therapeutic drugs, are currently being investigated as potential cytotoxic agents and have shown a positive trend in preclinical research and have prompted numerous innovative strategies in order to combat cancer and expedite the clinical research. Natural products are becoming increasingly important for drug discovery due to their high molecular diversity and novel biofunctionality. Furthermore, natural products can provide superior efficacy and safety due to their unique molecular properties. The objective of the current review is to provide an overview of the emergence of natural products for the treatment and prevention of cancer, such as chemosensitizers, immunotherapeutics, combinatorial therapies with other anticancer drugs, novel formulations of natural products, and the molecular mechanisms underlying their anticancer properties.

Hydrogen sulfide-induced oxidative stress mediated apoptosis via mitochondria pathway in embryo-larval stages of zebrafish

Hydrogen sulfide (H₂S), a highly toxic gas, has become a polluting gas that cannot be ignored, while H₂S exposure results in acute or chronic poisoning or even death in humans or animals and plants, but the relevant mechanisms remain poorly understood. In this study, 9-day-old zebrafish larvae were exposed continuously to culture medium containing 30 μM survival rate was counted on H₂S, and our results indicated that H₂S exposure increased intracellular ROS, Ca²⁺, NO and MDA contents and decreased SOD activity, meaning that H₂S caused oxidative stress in embryo-larval stages of zebrafish. Furthermore, we found that transgenic zebrafish (cms Tg/+ AB) displayed a lower fluorescence intensity, and cytochrome c oxidase (COX) activity and JC-1 monomer fluorescence ratio increased under H₂S treatment conditions. These findings indicated that H₂S caused mitochondrial dysfunction. Moreover, in this experiment, after H₂S treatment, the increase of apoptotic cells, activity of caspase 3 and transcription of typical apoptosis-associated genes including BCL2 associated agonist of cell death (Bad), and BCL2 associated X apoptosis (Baxa) and so on were found, which suggested that H₂S caused apoptosis in zebrafish larvae. Therefore, our data meant that H₂S-traggered oxidative stress mediate mitochondrial dysfunction, thus triggering apoptosis. In conclusion, oxidative stress triggered H₂S-induced apoptosis via mitochondria pathway in embryo-larval stages of zebrafish.

Label-Free Target Identification Reveals the Anticancer Mechanism of a Rhenium Isonitrile Complex

Elucidation of the molecular mechanism of therapeutic agents and potential candidates is in high demand. Interestingly, rhenium-based complexes have shown a highly selective anticancer effect, only on cancer cells, unlike platinum-based drugs, such as cisplatin and carboplatin. These differences might be attributed to their different molecular targets. We confirmed that the target of tricarbonyl rhenium isonitrile polypyridyl (TRIP) complex is a protein, not DNA, using ICP-MS analysis and identified heat shock protein 60 (HSP60) as its target protein using a label-free target identification method. The subsequent biological evaluation revealed that TRIP directly inhibits the chaperone function of HSP60 and induces the accumulation of misfolded proteins in mitochondria, thereby leading to the activation of mitochondrial unfolded protein response (mtUPR)-mediated JNK2/AP-1/CHOP apoptotic pathway.

Synergistic inhibition of the growth of MDA‑MB‑231 cells in triple‑negative breast cancer by salinomycin combined with 17‑AAG and its mechanism

Salinomycin (SAL), a typical ion carrier antibiotic, inhibits tumor growth and metastasis by inducing apoptosis or autophagy in cancer or cancer stem cells and thus overcomes drug resistance. 17-allylamino-17-demethoxygeldanamycin (17-AAG), a heat shock protein Hsp90 competitive inhibitor, also has a role in inhibiting tumor development. However, their combination on the growth of breast cancer cells and its specific mechanism remains to be elucidated. The present study tested the influence of SAL and 17-AAG on cell growth, apoptosis and autophagy by MTT assays, Annexin V-FITC and propidium iodide double staining assay and immunoelectron microscopy. The influence of SAL and 17-AAG on proteomics was investigated by isobaric tag for relative and absolute quantitation. It was found that SAL combined with 17-AAG synergistically inhibited the cell growth and induced the apoptosis in a concentration-dependent manner, with the expression of caspase 3 and Bcl-2 were decreased while the expression of Bax was increased. In addition, SAL combined with 17-AAG inhibited autophagy, with the expression of microtubule-associated protein 1 light chain 3, Beclin1, p62 being decreased. Mechanistically, SAL combined with 17-AAG synergistically inhibited the reactive oxygen species/JNK signaling pathway. In conclusion, SAL combined with 17-AAG had a synergistic inhibitory effect on cell growth of breast cancer via inducing apoptosis and inhibiting autophagy. The present study might provide a new strategy for potential clinical application of SAL as a new anti-tumor drug especially as a drug combination with other molecular targeting therapeutics.

2,5-dimethyl celecoxib induces apoptosis and autophagy via activation of ROS/JNK axis in nasopharyngeal carcinoma cells

2,5-dimethyl celecoxib (DMC), a close derivative of celecoxib, has also been reported to have anticancer effects. However, the effects and underlying molecular mechanisms of DMC with respect to nasopharyngeal carcinoma are still largely unknown. In this study, we present that DMC has displayed anticancer potency in nasopharyngeal carcinoma in vitro and in vivo. Mechanistically, we found DMC induced apoptosis and autophagy for anticancer therapy against nasopharyngeal carcinoma. Furthermore, DMC-induced autophagy could remarkably attenuate after the treatment of reactive oxygen species (ROS) scavenger N-acetyl cysteine (NAC) and c-Jun N-terminal kinase (JNK) inhibitor SP600125 (SP). Taken together, these results suggested DMC induced apoptosis and autophagic death via activation of ROS/JNK axis in NPC cells, which providing us new insights into developing potential therapeutic agents for nasopharyngeal carcinoma patients.

Decreased expression of IDH1 by chronic unpredictable stress suppresses proliferation and accelerates senescence of granulosa cells through ROS activated MAPK signaling pathways

Studies suggested that psychosocial stress was associated with female fertility decline, but the underlying mechanisms remained unclear. Granulosa cells (GCs) are important somatic cells to support follicular development and oocyte maturation. Herein, by using a mouse model of chronic unpredictable stress (CUS), we found that CUS induced oxidative stress damage in mouse ovaries, also inhibited GCs proliferation and accelerated GCs senescence. Isocitrate dehydrogenase-1 (IDH1), an antioxidant related gene by generating NADPH, was shown to be downregulated in GCs of CUS mice. Consistently, IDH1 knockdown inhibited cell proliferation and accelerated cellular senescence in KGN cells in vitro. In addition, IDH1 knockdown increased ROS content, induced autophagy activation and triggered cell cycle arrest in S and G2/M phases in KGN cells, which could be rescued by N-acetyl-l-cysteine (NAC), a ROS scavenger in these cells. Besides, IDH1 knockdown activated MAPK signaling pathways, including ERK, JNK and p38 signaling pathways in KGN cells, while NAC could suppress the activation. Through using inhibitors of MAPK signaling pathways, we showed that the activation of ERK pathway participated in autophagy related cell proliferation inhibition and cellular senescence, whereas JNK and p38 MAPK signaling pathways took part in regulation cell cycle arrest associated cell proliferation inhibitory and senescence in IDH1 knockdown KGN cells. Our findings suggested that downregulated expression of IDH1 induced by CUS has a physiological function in GCs proliferation and senescence through ROS activated MAPK signaling pathways, and improvement of IDH1 activity might be a beneficial therapeutic strategy for ovarian dysfunction.

Roflumilast prevents ischemic stroke-induced neuronal damage by restricting GSK3β-mediated oxidative stress and IRE1α/TRAF2/JNK pathway

Inhibition of phosphodiesterase 4 (PDE4) protects against neuronal apoptosis induced by cerebral ischemia. However, the exact mechanisms responsible for the protection of PDE4 inhibition have not been completely clarified. Roflumilast (Roflu) is an FDA-approved PDE4 inhibitor for the treatment of chronic obstructive pulmonary disease. The potential protective role of Roflu against ischemic stroke-associated neuronal injury remains unexplored. In this study, we investigated the effect and mechanism of Roflu against ischemic stroke using in vitro oxygen-glucose deprivation reperfusion (OGD/R) and in vivo rat middle cerebral artery occlusion (MCAO) models. We demonstrated that Roflu significantly reduced the apoptosis of HT-22 cells exposed to OGD/R, enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf-2), and reduced oxidative stress. Treatment with Roflu increased the phosphorylation of protein kinase B (Akt) and glycogen synthase kinase 3β (GSK3β) but decreased the level of phosphorylated inositol requiring enzyme 1α (IRE1α). Interestingly, constitutively active GSK3β (S9A) mutation abolished the effects of Roflu on oxidative stress and IRE1α phosphorylation. Moreover, Roflu decreased the binding of IRE1α to tumor necrosis factor receptor-associated factor 2 (TRAF2) and attenuated the phosphorylation of c-Jun N-terminal kinase (JNK). We also found that PDE4B knockdown reduced the phosphorylation of both IRE1α and JNK, while overexpression of PDE4B antagonized the role of PDE4B knockdown on the activation of IRE1α and JNK. Besides, the inhibition of PDE4 by Roflu produced similar effects in primary cultured neurons. Finally, Roflu ameliorated MCAO-induced cerebral injury by decreasing infarct volume, restoring neurological score, and reducing the phosphorylation of IRE1α and JNK. Collectively, these data suggest that Roflu protects neurons from cerebral ischemia reperfusion-mediated injury via the activation of GSK3β/Nrf-2 signaling and suppression of the IRE1α/TRAF2/JNK pathway. Roflu has the potential as a protective drug for the treatment of cerebral ischemia.