Dihydroartemisinin inhibits HepG2.2.15 proliferation by inducing cellular senescence and autophagy

TCM targets ferroptosis: potential treatments for cancer

Ferroptosis is caused by the accumulation of cellular reactive oxygen species that exceed the antioxidant load that glutathione (GSH) and phospholipid hydroperoxidases with GSH-based substrates can carry When the antioxidant capacity of cells is reduced, lipid reactive oxygen species accumulate, which can cause oxidative death. Ferroptosis, an iron-dependent regulatory necrosis pathway, has emerged as a new modality of cell death that is strongly associated with cancer. Surgery, chemotherapy and radiotherapy are the main methods of cancer treatment. However, resistance to these mainstream anticancer drugs and strong toxic side effects have forced the development of alternative treatments with high efficiency and low toxicity. In recent years, an increasing number of studies have shown that traditional Chinese medicines (TCMs), especially herbs or herbal extracts, can inhibit tumor cell growth and metastasis by inducing ferroptosis, suggesting that they could be promising agents for cancer treatment. This article reviews the current research progress on the antitumor effects of TCMs through the induction of ferroptosis. The aim of these studies was to elucidate the potential mechanisms of targeting ferroptosis in cancer, and the findings could lead to new directions and reference values for developing better cancer treatment strategies.

Molecular mechanisms and therapeutic applications of huaier in breast cancer treatment

Breast cancer is one of the most common female malignant tumors today and represents a serious health risk for women. Although the survival rate and quality of life of patients with breast cancer are improving with the continuous development of medical technology, metastasis, recurrence, and drug resistance of breast cancer remain a significant problem. Huaier, a traditional Chinese medicine (TCM) fungus, is a type of Sophora embolism fungus growing on old Sophora stems. The polysaccharides of Trametes robiniophila Murr (PS-T) are the main active ingredient of Huaier. There is increasing evidence that Huaier has great potential in breast cancer treatment, and its anti-cancer mechanism may be related to a variety of biological activities, such as the inhibition of cell proliferation, metastasis, tumor angiogenesis, the promotion of cancer cell death, and regulation of tumor-specific immunity. There is growing evidence that Huaier may be effective in the clinical treatment of breast cancer. This review systematically summarizes the basic and clinical studies on the use of Huaier in the treatment of breast cancer, providing useful information to guide the clinical application of Huaier and future clinical studies.

Natural bioactive compounds-doxorubicin combinations targeting topoisomerase II-alpha: Anticancer efficacy and safety

Cancer is one of the leading causes of death worldwide, so pursuing effective and safe therapeutics for cancer is a key research objective nowadays. Doxorubicin (DOX) is one of the commonly prescribed chemotherapeutic agents that has been used to treat cancer with its antimitotic properties via inhibition of topoisomerase II (TOP2) activity. However, many problems hinder the broad use of DOX in clinical practice, including cardiotoxicity and drug resistance. Research in drug discovery has confirmed that natural bioactive compounds (NBACs) display a wide range of biological activities correlating to anticancer outcomes. The combination of NBACs has been seen to be an ideal candidate that might increase the effectiveness of DOX therapy and decreases its unfavorable adverse consequences. The current review discusses the chemo-modulatory mechanism and the protective effects of combined DOX with NBACs with a binding affinity (pKi) toward TOP2A more than pKi of DOX. This review will also discuss and emphasize the molecular mechanisms to provide a pathway for further studies to reveal other signaling pathways. Taken together, understanding the fundamental mechanisms and implications of combined therapy may provide a practical approach to battling cancer diseases.

Natural biomolecules and derivatives as anticancer immunomodulatory agents

Despite advancements in chemotherapy, the issue of resistance and non-responsiveness to many chemotherapeutic drugs that are currently in clinical use still remains. Recently, cancer immunotherapy has gathered attention as a novel treatment against select cancers. Immunomodulation is also emerging as an effective strategy to improve efficacy. Natural phytochemicals, with known anticancer properties, been reported to mediate their effects by modulating both traditional cancer pathways and immunity. The mechanism of phytochemical mediated-immunomodulatory activity may be attributed to the remodeling of the tumor immunosuppressive microenvironment and the sensitization of the immune system. This allows for improved recognition and targeting of cancer cells by the immune system and synergy with chemotherapeutics. In this review, we will discuss several well-known plant-derived biomolecules and examine their potential as immunomodulators, and therefore, as novel immunotherapies for cancer treatment.

Dihydroartemisinin Potentiates VEGFR-TKIs Antitumorigenic Effect on Osteosarcoma by Regulating Loxl2/VEGFA Expression and Lipid Metabolism Pathway

Anti-angiogenesis therapy has shown significant anti-tumor effects against a variety of cancers. But resistance to antiangiogenic drugs, intrinsic and evasive, is frequently found in patients during treatment. Here, we report that dihydroartemisinin (DHA), a derivative of the Chinese medicine artemisinin, enhances antiangiogenic drug-induced cytotoxicity in osteosarcoma (OS) cells. Proteomics analysis revealed that DHA treatment significantly affected the activity of the collagen-modifying enzyme lysyl oxidase-like 2 (LOXL2), a regulatory gene associated with poor prognosis of OS. Furthermore, we found that DHA reduced the expression of vascular endothelial growth factor (VEGFA) by downregulating LOXL2. This mechanism was confirmed by QRT-PCR, western blot, and ELISA assays. Correspondingly, vector-enforced expression of LOXL2 markedly reduced VEGFA secretion. Untargeted metabolomic analysis revealed that the lipid metabolism that confers antiangiogenic drug resistance, was also interfered with by DHA. Thus, DHA not only exerts antitumor effects in OS cells directly but also synergizes with the antiangiogenic drug by regulating vascular endothelial growth factor A (VEGFA) expression and lipid metabolism.

Network Pharmacology-Based Exploration on the Intervention of Qinghao Biejia Decoction on the Inflammation-Carcinoma Transformation Process of Chronic Liver Disease via MAPK and PI3k/AKT Pathway

Chronic liver disease(CLD) is a slow-developing and long-term disease that can cause serious damage to the liver. Thus far, it has been associated with viral hepatitis, non-alcoholic fatty liver disease(NAFLD), alcoholic liver disease(ALD), hepatic fibrosis(HF), liver cirrhosis (LC), and liver cancer. Qinghao Biejia Decoction (QBD) is a classic ancient Chinese herbal prescription with strong immune-enhancing, anti-inflammatory, and anti-tumor effects. In this study, we used a network pharmacology approach to investigate the molecular mechanisms of QBD in the inflammation-carcinoma transformation process of chronic liver disease. Two key drug targets, MAPK1 and PIK3CA, were screened using network pharmacology and molecular docking techniques, revealing dihydroartemisinin, artesunate, 12-O-Nicotinoylisolineolone, caffeic acid, and diincarvilone A as active ingredients involved in QBD mechanisms. The main signaling pathways involved were the PI3K-AKT signaling pathway and MAPK signaling pathway. In summary, our results indicated that QBD affects the inflammatory transformation of chronic liver disease through MAPK1 and PIK3CA and signaling pathways MAPK and PI3K/AKT. These data provide research direction for investigating the mechanisms underlying the inflammation-carcinoma transformation process in QBD for chronic liver disease.

Potential roles and molecular mechanisms of phytochemicals against cancer

Increasing evidence has been reported regarding phytochemicals, plant secondary metabolites, having therapeutic functions against numerous human diseases. Recently, phytochemicals (flavonoids, polyphenols, terpenoids, alkaloids, saponins, coumarins and so on) have shown promising anti-cancer efficacy with their distinct advantages of high efficiency and low toxicity. They regulate programmed cell death (apoptosis, pyroptosis, and autophagy), migration and senescence-related signaling pathways of cancer via the modulation of reactive oxygen species (ROS), mitogen activated protein kinase (MAPK) pathway, deleted in liver cancer 1 (DLC1), nuclear factor κ light-chain-enhancer of activated B cell (NF-κB) pathways and glycolytic enzymes. Here, we review the molecular mechanisms by which phytochemicals prevent the development of cancer. Furthermore, phytochemicals combined with chemotherapeutic agents could target the crosstalk among multiple signal cascades to block chemoresistance and attenuate carcinogenic properties, and can be considered as a novel and potential therapeutic strategy. Our review highlights that the mechanisms and promising applications are required to be understood to decisively establish the anti-cancer efficacy of natural phytochemicals.

The Regulatory Effects of Traditional Chinese Medicine on Ferroptosis

Traditional Chinese medicine (TCM) has significantly contributed to protecting human health and promoting the progress of world civilization. A total of 2,711 TCMs are included in the 2020 version of the Chinese Pharmacopoeia, which is an integral part of the world’s medical resources. Tu Youyou and her team discovered and purified artemisinin. And their contributions made the values and advantageous effects of TCM more and more recognized by the international community. There has been a lot of studies on TCM to treat diseases through antioxidant mechanisms, the reports on the new mechanisms beyond antioxidants of TCM has also increased year by year. Recently, many TCMs appear to have significant effects in regulating ferroptosis. Ferroptosis is an iron-dependent, non-apoptotic, regulated cell death characterized by intracellular lipid peroxide accumulation and oxidative membrane damage. Recently, accumulating studies have demonstrated that numerous organ injuries and pathophysiological process of many diseases are companied with ferroptosis, such as cancer, neurodegenerative disease, acute renal injury, arteriosclerosis, diabetes, and ischemia-reperfusion injury. This work mainly introduces dozens of TCMs that can regulate ferroptosis and their possible mechanisms and targets.

Dihydroartemisinin promoted FXR expression independent of YAP1 in hepatocellular carcinoma

Loss of FXR, one of bile acid receptors, enlarged livers. Yes-associated protein 1 (YAP1), a dominant oncogene, promotes hepatocellular carcinoma (HCC). However, the relationship between FXR and YAP1 was unspecified in bile acid homeostasis in HCC. Here, we used TIMER2.0, the Cancer Genome Atlas (TCGA) Database, and Kaplan-Meier Plotter Database and discovered that FXR was positively correlated with better prognosis in liver cancer patients. Our previous research showed that dihydroartemisinin (DHA) inhibited cell proliferation in HepG2 and HepG22215 cells. However, the relationship of YAP1 and the bile acid receptor FXR remains elusive during DHA treatment. Furthermore, we showed that DHA improved FXR and reduced YAP1 in the liver cancer cells and mice. Additionally, the expression of nucleus protein FXR was enhanced in Yap1^LKO mice with liver cancer. DHA promoted the expression level of whole and nuclear protein FXR independent of YAP1 in Yap1^LKO mice with liver cancer. DHA declined cholesterol 7α-hydroxylase, but not sterol 27-hydroxylase, and depressed cholic acid and chenodeoxycholic acid of liver tissue in Yap1^LKO mice with liver cancer. Generally, our results suggested that DHA improved FXR and declined YAP1 to suppress bile acid metabolism. Thus, we suggested that FXR acted as a potential therapeutic target in HCC.

Targeting TCTP sensitizes tumor to T cell-mediated therapy by reversing immune-refractory phenotypes

Immunotherapy has emerged as a powerful approach to cancer treatment. However, immunotherapeutic resistance limits its clinical application. Therefore, identifying immune-resistant factors, which can be targeted by clinically available drugs and it also can be a companion diagnostic marker, is needed to develop combination strategies. Here, using the transcriptome data of patients, and immune-refractory tumor models, we identify TCTP as an immune-resistance factor that correlates with clinical outcome of anti-PD-L1 therapy and confers immune-refractory phenotypes, decreased T cell trafficking to the tumor and resistance to cytotoxic T lymphocyte-mediated tumor cell killing. Mechanistically, TCTP activates the EGFR-AKT-MCL-1/CXCL10 pathway by phosphorylation-dependent interaction with Na, K ATPase. Furthermore, treatment with dihydroartenimsinin, the most effective agent impending the TCTP-mediated-refractoriness, synergizes with T cell-mediated therapy to control immune-refractory tumors. Thus, our findings suggest a role of TCTP in promoting immune-refractoriness, thereby encouraging a rationale for combination therapies to enhance the efficacy of T cell-mediated therapy.

Translationally controlled tumor protein (TCTP) regulates several cellular processes, including apoptosis, and is overexpressed in several cancer types. Here, the authors report that high levels of TCTP are associated with poor response to anti-PD-L1 and that TCTP targeting increases the efficacy of T cell-mediated anti-tumor therapy.

Artemisinin-Type Drugs in Tumor Cell Death: Mechanisms, Combination Treatment with Biologics and Nanoparticle Delivery

Artemisinin, the most famous anti-malaria drug initially extracted from Artemisia annua L., also exhibits anti-tumor properties in vivo and in vitro. To improve its solubility and bioavailability, multiple derivatives have been synthesized. However, to reveal the anti-tumor mechanism and improve the efficacy of these artemisinin-type drugs, studies have been conducted in recent years. In this review, we first provide an overview of the effect of artemisinin-type drugs on the regulated cell death pathways, which may uncover novel therapeutic approaches. Then, to overcome the shortcomings of artemisinin-type drugs, we summarize the recent advances in two different therapeutic approaches, namely the combination therapy with biologics influencing regulated cell death, and the use of nanocarriers as drug delivery systems. For the former approach, we discuss the superiority of combination treatments compared to monotherapy in tumor cells based on their effects on regulated cell death. For the latter approach, we give a systematic overview of nanocarrier design principles used to deliver artemisinin-type drugs, including inorganic-based nanoparticles, liposomes, micelles, polymer-based nanoparticles, carbon-based nanoparticles, nanostructured lipid carriers and niosomes. Both approaches have yielded promising findings in vitro and in vivo, providing a strong scientific basis for further study and upcoming clinical trials.

Celecoxib prevents tumor necrosis factor-α (TNF-α)-induced cellular senescence in human chondrocytes

Osteoarthritis (OA) is a cartilage degenerative disease commonly observed in the elderly population and significantly impacts the normal life of OA patients. It has been reported that the development of pathological cell senescence in chondrocytes is involved in the pathogenesis of OA. Celecoxib is a common non-steroidal anti-inflammatory drug, and it has been recently reported to exert therapeutic effects on OA. However, its underlying mechanism is still unclear. The present study intends to explore its mechanism and provide fundamental evidence for the application of Celecoxib in the treatment of clinical OA. Tumor necrosis factor-α (TNF-α) was utilized to establish an in vitro model of chondrocytes senescence. The elevated reactive oxygen species (ROS) generation, increased cell cycle arrest in G0/G1 phase, reduced telomerase activity, and upregulated senescence-associatedβ-galactosidase (SA-β-Gal) staining were all observed in TNF-α-treated chondrocytes, which were then dramatically reversed by 10 and 20 μM Celecoxib. In addition, the upregulated DNA damage biomarkers, p-ATM, and p-CHK2, observed in TNF-α-treated chondrocytes were significantly downregulated by 10 and 20 μM Celecoxib. Lastly, the expression level of p21 and p53 was greatly elevated in chondrocytes by stimulation with TNF-α which was then pronouncedly repressed by treatment with Celecoxib. Taken together, our data reveal that Celecoxib ameliorated TNF-α-induced cellular senescence in human chondrocytes.

Human Telomerase Reverse Transcriptase as a Therapeutic Target of Dihydroartemisinin for Esophageal Squamous Cancer

Objective: To elucidate the oncogenic role of human telomerase reverse transcriptase (hTERT) in esophageal squamous cancer and unravel the therapeutic role and molecular mechanism of dihydroartemisinin (DHA) by targeting hTERT. Methods: The expression of hTERT in esophageal squamous cancer and the patients prognosis were analyzed by bioinformatic analysis from TCGA database, and further validated with esophageal squamous cancer tissues in our cohort. The Cell Counting Kit-8 (CCK8) and colony formation assay were used to evaluate the proliferation of esophageal squamous cancer cell lines (Eca109, KYSE150, and TE1) after hTERT overexpression or treated with indicated concentrations of DHA. Transwell migration assay and scratch assay were employed to determine the migration abilities of cancer cells. Fluorescence microscopy and flow cytometry were conducted to measure the intracellular reactive oxygen species (ROS) levels in cancer cells after treated with DHA. Moreover, RT-PCR and Western blot were performed to test the alteration of associated genes on mRNA and protein level in DHA treated esophageal squamous cancer cell lines, respectively. Furthermore, tumor-bearing nude mice were employed to evaluate the anticancer effect of DHA in vivo. Results: We found that hTERT was significantly upregulated in esophageal squamous cancer both from TCGA database and our cohort also. Overexpression of hTERT evidently promoted the proliferation and migration of esophageal squamous cancer cells in vitro. Moreover, DHA could significantly inhibit the proliferation and migration of esophageal cancer cell lines Eca109, KYSE150, and TE1 in vitro, and significantly down-regulate the expression of hTERT on both mRNA and protein level in a time- and dose-dependent manner as well. Further studies showed that DHA could induce intracellular ROS production in esophageal cancer cells and down-regulate SP1 expression, a transcription factor that bound to the promoter region of hTERT gene. Moreover, overexpression of SP1 evidently promoted the proliferation and migration of Eca109 and TE1 cells. Intriguingly, rescue experiments showed that inhibiting ROS by NAC alleviated the downregulation of SP1 and hTERT in cells treated with DHA. Furthermore, overexpression of SP1 or hTERT could attenuate the inhibition effect of DHA on the proliferation and migration of Eca109 cells. In tumor-bearing nude mice model, DHA significantly inhibited the growth of esophageal squamous cancer xenografts, and downregulated the expression of SP1 and hTERT protein, while no side effects were observed from heart, kidney, liver, and lung tissues by HE stain. Conclusion: hTERT plays an oncogenic role in esophageal squamous cancer and might be a therapeutic target of DHA through regulating ROS/SP1 pathway.

Dihydroartemisinin: A Potential Drug for the Treatment of Malignancies and Inflammatory Diseases

Dihydroartemisinin (DHA) has been globally recognized for its efficacy and safety in the clinical treatment of malaria for decades. Recently, it has been found that DHA inhibits malignant tumor growth and regulates immune system function in addition to anti-malaria. In parasites and tumors, DHA causes severe oxidative stress by inducing excessive reactive oxygen species production. DHA also kills tumor cells by inducing programmed cell death, blocking cell cycle and enhancing anti-tumor immunity. In addition, DHA inhibits inflammation by reducing the inflammatory cells infiltration and suppressing the production of pro-inflammatory cytokines. Further, genomics, proteomics, metabolomics and network pharmacology of DHA therapy provide the basis for elucidating the pharmacological effects of DHA. This review provides a summary of the recent research progress of DHA in anti-tumor, inhibition of inflammatory diseases and the relevant pharmacological mechanisms. With further research of DHA, it is likely that DHA will become an alternative therapy in the clinical treatment of malignant tumors and inflammatory diseases.

Anti-malarial drug: the emerging role of artemisinin and its derivatives in liver disease treatment

Artemisinin and its derivatives belong to a family of drugs approved for the treatment of malaria with known clinical safety and efficacy. In addition to its anti-malarial effect, artemisinin displays anti-viral, anti-inflammatory, and anti-cancer effects in vivo and in vitro. Recently, much attention has been paid to the therapeutic role of artemisinin in liver diseases. Several studies suggest that artemisinin and its derivatives can protect the liver through different mechanisms, such as those pertaining to inflammation, proliferation, invasion, metastasis, and induction of apoptosis and autophagy. In this review, we provide a comprehensive discussion of the underlying molecular mechanisms and signaling pathways of artemisinin and its derivatives in treating liver diseases. Further pharmacological research will aid in determining whether artemisinin and its derivatives may serve as promising medicines for the treatment of liver diseases in the future.

Terpenoids' anti-cancer effects: focus on autophagy

Terpenoids are the largest class of natural products, most of which are derived from plants. Amongst their numerous biological properties, their anti-tumor effects are of interest for they are extremely diverse which include anti-proliferative, apoptotic, anti-angiogenic, and anti-metastatic activities. Recently, several in vitro and in vivo studies have been dedicated to understanding the 'terpenoid induced autophagy' phenomenon in cancer cells. Light has already been shed on the intricacy of apoptosis and autophagy relationship. This latter crosstalk is driven by the delicate balance between activating or silencing of certain proteins whereby the outcome is expressed via interrelated signaling pathways. In this review, we focus on nine of the most studied terpenoids and on their cell death and autophagic activity. These terpenoids are grouped in three classes: sesquiterpenoid (artemisinin, parthenolide), diterpenoids (oridonin, triptolide), and triterpenoids (alisol, betulinic acid, oleanolic acid, platycodin D, and ursolic acid). We have selected these nine terpenoids among others as they belong to the different major classes of terpenoids and our extensive search of the literature indicated that they were the most studied in terms of autophagy in cancer. These terpenoids alone demonstrate the complexity by which these secondary metabolites induce autophagy via complex signaling pathways such as MAPK/ERK/JNK, PI3K/AKT/mTOR, AMPK, NF-kB, and reactive oxygen species. Moreover, induction of autophagy can be either destructive or protective in tumor cells. Nevertheless, should this phenomenon be well understood, we ought to be able to exploit it to create novel therapies and design more effective regimens in the management and treatment of cancer.

Dihydroartemisinin Inhibits mTORC1 Signaling by Activating the AMPK Pathway in Rhabdomyosarcoma Tumor Cells

Dihydroartemisinin (DHA), an anti-malarial drug, has been shown to possess potent anticancer activity, partly by inhibiting the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) signaling. However, how DHA inhibits mTORC1 is still unknown. Here, using rhabdomyosarcoma (RMS) as a model, we found that DHA reduced cell proliferation and viability in RMS cells, but not those in normal cells, which was associated with inhibition of mTORC1. Mechanistically, DHA did not bind to mTOR or FK506 binding protein 12 (FKBP12). In addition, DHA neither inhibited insulin-like growth factor-1 receptor (IGF-1R), phosphoinositide 3-kinase (PI3K), and extracellular signal-regulated kinase ½ (Erk1/2), nor activated phosphatase and tensin homolog (PTEN) in the cells. Rather, DHA activated AMP-activated protein kinase (AMPK). Pharmacological inhibition of AMPK, ectopic expression dominant negative or kinase-dead AMPK, or knockdown of AMPKα attenuated the inhibitory effect of DHA on mTORC1 in the cells. Additionally, DHA was able to induce dissociation of regulatory-associated protein of mTOR (raptor) from mTOR and inhibit mTORC1 activity. Moreover, treatment with artesunate, a prodrug of DHA, dose-dependently inhibited tumor growth and concurrently activated AMPK and suppressed mTORC1 in RMS xenografts. The results indicated that DHA inhibits mTORC1 by activating AMPK in tumor cells. Our finding supports that DHA or artesunate has a great potential to be repositioned for treatment of RMS.

Dihydroartemisinin regulates apoptosis, migration, and invasion of ovarian cancer cells via mediating RECK

BACKGROUND

Dihydroartemisinin (DHA) possesses an inhibitory effect on ovarian cancer and promotes reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expression in glioma cells. This study explored the role of DHA and RECK on ovarian cancer.

METHODS

The RECK level in ovarian cancer was analyzed under GEPIA 2 database and proved by RT-qPCR. After being treated with DHA or infected with siRECK lentivirus, the viability, apoptosis, migration, and invasion of ovarian cancer cells were evaluated by CCK-8, flow cytometry, wound healing, and transwell assays. Also, the expressions of factors related to apoptosis and epithelial-mesenchymal transition were measured by Western blot or RT-qPCR.

RESULTS

DHA-treatment weakened the viability, migration, invasion, and enhanced apoptosis of ovarian cancer cells. DHA also down-regulated the levels of Bcl-2, N-cadherin, and Vimentin, and up-regulated the levels of Bax, C-caspase-3 and E-cadherin in ovarian cancer cells. RECK was lowly expressed in both ovarian cancer tissues and cells. siRECK not only had an effect opposite to DHA on the viability, apoptosis, migration, invasion, and related-factors of ovarian cancer cells but also offset the effect of DHA on ovarian cancer cells.

CONCLUSION

DHA regulated apoptosis, migration, and invasion of ovarian cancer cells via mediating RECK.

AMPK-mTOR-ULK1-mediated autophagy protects carbon tetrachloride-induced acute hepatic failure by inhibiting p21 in rats

Autophagy is a lysosomal-dependent degradation pathway in eukaryotic cells. Recent studies have reported that autophagy can facilitate the activation of hepatic stellate cells (HSCs) and fibrogenesis of the liver during long-term carbon tetrachloride (CCl₄) exposure. However, little is known about the role of autophagy in CCl₄-induced acute hepatic failure (AHF). This study aimed to identify whether modulation of autophagy can affect CCl₄-induced AHF and evaluate the upstream signaling pathways mediated by CCl₄-induced autophagy in rats. The accumulation of specific punctate distribution of endogenous LC3-II, increased expression of LC3-II, Atg5, and Atg7 genes/proteins, and decreased expression of p62 gene were observed after acute liver injury was induced by CCl₄ in rats, indicating that CCl₄ resulted in a high level of autophagy. Moreover, loss of autophagic function by using chloroquine (CQ, an autophagic inhibitor) aggravated liver function, leading to increased expression of p21 (a cyclin-dependent kinase inhibitor) in CCl₄-treated rats. Furthermore, the AMPK-mTORC1-ULK1 axis was found to serve a function in CCl₄-induced autophagy. These results reveal that AMPK-mTORC1-ULK1 signaling-induced autophagy has a protective role in CCl₄-induced hepatotoxicity by inhibiting the p21 pathway. This study suggests a useful strategy aimed at ameliorating CCl₄-induced acute hepatotoxicity by autophagy.

pH-Sensitive Nanoparticles Codelivering Docetaxel and Dihydroartemisinin Effectively Treat Breast Cancer by Enhancing Reactive Oxidative Species-Mediated Mitochondrial Apoptosis

Tumor growth and metastasis are the major causes of high mortality in breast cancer. We previously constructed pH-sensitive nanoparticles (D/D NPs) for the codelivery of docetaxel (DTX) and dihydroartemisinin (DHA) and demonstrated that D/D NPs showed anticancer activity in breast cancer cells in vitro. The present study further investigated the therapeutic effect of D/D NPs on orthotopic breast cancer in vivo and examined the antitumor mechanism of D/D NPs. D/D NPs significantly increased the apoptosis of 4T1 cells with a synergistic effect of DTX and DHA. D/D NPs increased reactive oxygen species, reduced mitochondrial membrane potential, increased the expression of p53, and induced cytochrome c release into the cytoplasm to activate caspase-3. In an orthotopic metastatic breast cancer mouse model derived from 4T1 cells, D/D NPs inhibited tumor growth and prevented lung metastasis due to the synergistic effect of DTX and DHA. No distinct changes were observed in the histology of major organs. These results indicate that pH-sensitive D/D NP-based combination therapy may be a promising strategy for the treatment of metastatic breast cancers via the ROS-mediated mitochondrial apoptosis pathway.

Dihydroartemisinin as a potential drug candidate for cancer therapy: a structural-based virtual screening for multitarget profiling

Cancer is a rapidly growing non-communicable disease worldwide that is responsible for high mortality rates, which account for 9.6 million death in 2018. Dihydroartemisinin (DHA) is an active metabolite of artemisinin, an active principle present in the Chinese medicinal plant Artemisia annua used for malaria treatment. Dihydroartemisinin possesses remarkable and selective anticancer properties however the underlying mechanism of the antitumor effects of DHA from the structural point of view is still not yet elucidated. In the present study, we employed molecular docking simulation techniques using Autodock suits to access the binding properties of dihydroartemisinin to multiple protein targets implicated in cancer pathogenesis. Its potential targets with comprehensive pharmacophore were predicted using a PharmMapper database. The co-crystallised structures of the protein were obtained from a Protein Data Bank and prepared for molecular docking simulation. Out of the 24 selected protein targets, DHA has shown about 29% excellent binding to the targets compared to their co-crystallised ligand. Additionally, 75% of the targets identified for dihydroartemisinin binding are protein kinases, and 25% are non-protein kinases. Hydroxyl functional group of dihydroartemisinin contributed to 58.5% of the total hydrogen interactions, while pyran (12.2%), endoperoxide (9.8%), and oxepane (19.5%) contributed to the remaining hydrogen bonding. The present findings have elucidated the possible antitumor properties of dihydroartemisinin through the structural-based virtual studies, which provides a lead to a safe and effective anticancer agent useful for cancer therapy.Communicated by Ramaswamy H. Sarma.

Cytotoxic and Anti-Plasmodial Activities of Stephania dielsiana Y.C. Wu Extracts and the Isolated Compounds

Natural products remain a viable source of novel therapeutics, and as detection and extraction techniques improve, we can identify more molecules from a broader set of plant tissues. The aim of this study was an investigation of the cytotoxic and anti-plasmodial activities of the methanol extract from Stephania dielsiana Y.C. Wu leaves and its isolated compounds. Our study led to the isolation of seven alkaloids, among which oxostephanine (1) is the most active against several cancer cell lines including HeLa, MDA-MB231, MDA-MB-468, MCF-7, and non-cancer cell lines, such as 184B5 and MCF10A, with IC₅₀ values ranging from 1.66 to 4.35 μM. Morever, oxostephanine (1) is on average two-fold more active against cancer cells than stephanine (3), having a similar chemical structure. Cells treated with oxostephanine (1) are arrested at G2/M cell cycle, followed by the formation of aneuploidy and apoptotic cell death. The G2/M arrest appears to be due, at least in part, to the inactivation of Aurora kinases, which is implicated in the onset and progression of many forms of human cancer. An in-silico molecular modeling study suggests that oxostephanine (1) binds to the ATP binding pocket of Aurora kinases to inactivate their activities. Unlike oxostephanine (1), thailandine (2) is highly effective against only the triple-negative MDA-MB-468 breast cancer cells. However, it showed excellent selectivity against the cancer cell line when compared to its effects on non-cancer cells. Furthermore, thailandine (2) showed excellent anti-plasmodial activity against both chloroquine-susceptible 3D7 and chloroquine-resistant W2 Plasmodium falciparum strains. The structure-activity relationship of isolated compound was also discussed in this study. The results of this study support the traditional use of Stephania dielsiana Y.C. Wu and the lead molecules identified can be further optimized for the development of highly effective and safe anti-cancer and anti-plasmodial drugs.

Iron Promotes Dihydroartemisinin Cytotoxicity via ROS Production and Blockade of Autophagic Flux via Lysosomal Damage in Osteosarcoma

Osteosarcoma cellular iron concentration is higher than that in normal bone cells and other cell types. High levels of cellular iron help catalyze the Fenton reaction to produce reactive oxygen species (ROS), which promotes cancer cell proliferation. Dihydroartemisinin (DHA), a classic anti-malarial drug, kills plasmodium through iron-dependent ROS generation. In this research, we observed the anti-osteosarcoma effects and mechanisms of DHA. We found that DHA induced ROS production, caused mitochondrial damage, and activated autophagy via stimulation of the ROS/Erk1/2 pathway. As the storage site for a pool of ferrous iron, lysosomes are often the key organelles affected by drugs targeting iron. In this study, we observed that DHA induced lysosomal superoxide production, leading lysosomal membrane permeabilization (LMP), and autophagic flux blockage. By reducing or increasing cellular iron using deferoxamine (DFO) or ferric ammonium citrate (FAC), respectively, we found that DHA inhibited osteosarcoma in an iron-dependent manner. Therefore, iron may be a potential adjuvant for DHA in osteosarcoma treatment.

Autophagy-dependent cell cycle arrest in esophageal cancer cells exposed to dihydroartemisinin

Background

Dihydroartemisinin (DHA), a derivate of artemisinin, is an effective antimalarial agent. DHA has been shown to exert anticancer activities to numerous cancer cells in the past few years, while the exact molecular mechanisms remain to be elucidated, especially in esophageal cancer.

Methods

Crystal violet assay was conducted to determine the cell viability of human esophageal cancer cell line Eca109 treated with DHA. Tumor-bearing nude mice were employed to evaluate the anticancer effect of DHA in vivo. Soft agar and crystal violet assays were used to measure the tumorigenicity of Eca109 cells. Flow cytometry was performed to evaluate ROS or cell cycle distribution. GFP-LC3 plasmids were delivered into Eca109 cells to visualize autophagy induced by DHA under a fluorescence microscope. The mRNA and protein levels of each gene were tested by qRT-PCR and western blot, respectively.

Results

Our results proved that DHA significantly reduced the viability of Eca109 cells in a dose- and time-dependent manner. Further investigation showed that DHA evidently induced cell cycle arrest at the G2/M phase in Eca109 cells. Mechanistically, DHA induced intracellular ROS generation and autophagy in Eca109 cells, while blocking ROS by an antioxidant NAC obviously inhibited autophagy. Furthermore, we found that telomere shelterin component TRF2 was down-regulated in Eca109 cells exposed to DHA through autophagy-dependent degradation, which could be rescued after autophagy was blocked by ROS inhibition. Moreover, the DNA damage response (DDR) was induced obviously in DHA treated cells. To further explore whether ROS or autophagy played a vital role in DHA induced cell cycle arrest, the cell cycle distribution of Eca109 cells was evaluated after ROS or autophagy blocking, and the results showed that autophagy, but not ROS, was essential for cell cycle arrest in DHA treated cells.

Conclusion

Taken together, DHA showed anticancer effect on esophageal cancer cells through autophagy-dependent cell cycle arrest at the G2/M phase, which unveiled a novel mechanism of DHA as a chemotherapeutic agent, and the degradation of TRF2 followed by DDR might be responsible for this cell phenotype.

Dihydroartemisinin Sensitizes Mutant p53 (R248Q)-Expressing Hepatocellular Carcinoma Cells to Doxorubicin by Inhibiting P-gp Expression

Mutant p53 (R248Q) induces doxorubicin (ADM) resistance in hepatocellular carcinoma (HCC). Dihydroartemisinin (DHA) can synergistically enhance anticancer effect of many chemotherapeutic agents. However, whether DHA could increase therapeutic efficacy of ADM in p53 (R248Q)-expressing HCC cells remains unknown. In the present study, we established mutant p53 (R248Q)-expressing Hep3B cells to study the effect and mechanism of DHA on ADM resistance and the synergistic effect of DHA with ADM. We found that P-gp was highly expressed in p53 (R248Q)-expressing Hep3B cells. As a result, cells expressing p53 (R248Q) displayed higher cell viability and lower cell apoptosis level upon ADM treatment. Meanwhile, phosphorylation levels of ERK1/2 and p65 were elevated in p53 (R248Q)-expressing Hep3B cells. However, combination of DHA and ADM treatment decreased cell viability and elevated cell apoptosis level in p53 (R248Q)-expressing Hep3B cells. Molecular dynamics simulations showed that DHA had the potential to bind with mutant p53 (R248Q) protein. Furthermore, DHA treatment decreased P-gp expression and inhibited phosphorylation levels of ERK1/2 and p65 in p53 (R248Q)-expressing Hep3B cells. Finally, DHA treatment could significantly reduce ADM efflux in p53 (R248Q)-expressing cells. Our results indicate that DHA could decrease P-gp expression via inhibiting the p53 (R248Q)-ERK1/2-NF-κB signaling pathway, which eventually confers sensitization of p53 (R248Q)-expressing HCC cells to ADM. Our study provides evidence for the potential application of DHA and ADM combination in treatment of mutant p53 (R248Q)-harbored HCC.