Artemisinin derivatives inhibit epithelial ovarian cancer cells via autophagy-mediated cell cycle arrest

Target prediction and potential application of dihydroartemisinin on hepatocarcinoma treatment

With high incidence of hepatocarcinoma and limited effective treatments, most patients suffer in pain. Antitumor drugs are single-targeted, toxicity, causing adverse side effects and resistance. Dihydroartemisinin (DHA) inhibits tumor through multiple mechanisms effectively. This study explores and evaluates safety and potential mechanism of DHA towards human hepatocarcinoma based on network pharmacology in a comprehensive way. Adsorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of DHA were evaluated with pkCSM, SwissADME, and ADMETlab. Potential targets of DHA were obtained from SwissTargetPrediction, Drugbank, TargetNET, and PharmMapper. Target gene of hepatocarcinoma was obtained from OMIM, GeneCards, and DisGeNET. Overlapping targets and hub genes were identified and analyzed for Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway. Molecular docking was utilized to investigate the interactions sites and hydrogen bonds. Cell counting kit-8 (CCK8), wound healing, invasion, and migration assays on HepG2 and SNU387 cell proved DHA inhibits malignant biological features of hepatocarcinoma cell. DHA is safe and desirable for clinical application. A total of 131 overlapping targets were identified. Biofunction analysis showed targets were involved in kinase activity, protein phosphorylation, intracellular reception, signal transduction, transcriptome dysregulation, PPAR pathway, and JAK-STAT signaling axis. Top 9 hub genes were obtained using MCC (Maximal Clique Centrality) algorithm, namely CDK1, CCNA2, CCNB1, CCNB2, KIF11, CHEK1, TYMS, AURKA, and TOP2A. Molecular docking suggests that all hub genes form a stable interaction with DHA for optimal binding energy were all less than - 5 kcal/mol. Dihydroartemisinin might be a potent and safe anticarcinogen based on its biological safety and effective therapeutic effect.

Dihydroartemisinin, a potential PTGS1 inhibitor, potentiated cisplatin-induced cell death in non-small cell lung cancer through activating ROS-mediated multiple signaling pathways

Dihydroartemisinin (DHA) exerts an anti-tumor effect in multiple cancers, however, the molecular mechanism of DHA and whether DHA facilitates the anti-tumor efficacy of cisplatin in non-small cell lung cancer (NSCLC) are unclear. Here, we found that DHA potentiated the anti-tumor effects of cisplatin in NSCLC cells by stimulating reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress, C-Jun-amino-terminal kinase (JNK) and p38 MAPK signaling pathways both in vitro and in vivo. Of note, we demonstrated for the first time that DHA inhibits prostaglandin G/H synthase 1 (PTGS1) expression, resulting in enhanced ROS production. Importantly, silencing PTGS1 sensitized DHA-induced cell death by increasing ROS production and activating ER-stress, JNK and p38 MAPK signaling pathways. In summary, our findings provided new experimental basis and therapeutic prospect for the combined therapy with DHA and cisplatin in some NSCLC patients.

Design, Synthesis, and Antitumor Activity Evaluation of Artemisinin Bivalent Ligands

Five artemisinin bivalent ligands molecules 4a-4e were designed, synthesized, and confirmed by 1H NMR, 13C NMR, and low-resolution mass spectrometry, and the bioactivities of the target compounds were investigated against four human tumor cell lines in vitro, including BGC-823, HepG-2, MCF-7, and HCT-116. The results showed 4a, 4d, and 4e exhibited significantly tumor cell inhibitory activity compared with the artemisinin and dihydroartemisinin; compound 4e has good biological activity inhibiting BGC-823 with an IC50 value of 8.30 μmol/L. Then, the good correlations with biological results were validated by molecular docking through the established bivalent ligands multi-target model, which showed that 4e could bind well with the antitumor protein MMP-9.

Medicinal and mechanistic overview of artemisinin in the treatment of human diseases

Artemisinin (ART) is a bioactive compound isolated from the plant Artemisia annua and has been traditionally used to treat conditions such as malaria, cancer, viral infections, bacterial infections, and some cardiovascular diseases, especially in Asia, North America, Europe and other parts of the world. This comprehensive review aims to update the biomedical potential of ART and its derivatives for treating human diseases highlighting its pharmacokinetic and pharmacological properties based on the results of experimental pharmacological studies in vitro and in vivo. Cellular and molecular mechanisms of action, tested doses and toxic effects of artemisinin were also described. The analysis of data based on an up-to-date literature search showed that ART and its derivatives display anticancer effects along with a wide range of pharmacological activities such as antibacterial, antiviral, antimalarial, antioxidant and cardioprotective effects. These compounds have great potential for discovering new drugs used as adjunctive therapies in cancer and various other diseases. Detailed translational and experimental studies are however needed to fully understand the pharmacological effects of these compounds.

Gambogenic acid induces apoptosis and autophagy through ROS-mediated endoplasmic reticulum stress via JNK pathway in prostate cancer cells

Prostate cancer (PCa) is the most common malignant tumor in males, which frequently develops into castration-resistant prostate cancer (CRPC) with limited therapies. Gambogenic acid (GNA), a flavonoids compound isolated from Gamboge, exhibits anti-tumor capacity in various cancers. Our results showed that GNA revealed not only antiproliferative and pro-apoptotic activities but also the induction of autophagy in PCa cells. In addition, autophagy inhibitor chloroquine enhanced the pro-apoptosis effect of GNA. Moreover, the activation of JNK pathway and the induction of apoptosis and autophagy triggered by GNA were attenuated by JNK inhibitor SP600125. We also found that GNA significantly promoted reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress. Meanwhile, suppressing ER stress with 4-phenylbutyric acid (4-PBA) markedly blocked the activation of JNK pathway induced by GNA. Further research indicated that ROS scavenger N-acetyl-L-cysteine (NAC) effectively abrogated ER stress and JNK pathway activation induced by GNA. Furthermore, NAC and 4-PBA significantly reversed GNA-triggered apoptosis and autophagy. Finally, GNA remarkably suppressed prostate tumor growth with low toxicity in vivo. In conclusion, the present study revealed that GNA induced apoptosis and autophagy through ROS-mediated ER stress via JNK signaling pathway in PCa cells. Thus, GNA might be a promising therapeutic drug against PCa.

High expression of CETN2 is associated with platinum resistance and poor prognosis in epithelial ovarian cancer

PURPOSE

The poor prognosis of ovarian cancer is largely due to platinum resistance. It has been demonstrated that nucleotide excision repair (NER) involving centrin-2(CETN2) is connected to platinum resistance in ovarian cancer. The molecular mechanism of CETN2 in ovarian cancer and the mechanism affecting the outcome of chemotherapy are unknown.

METHODS

The protein-protein interaction (PPI) network was mapped after obtaining the interacting proteins of CETN2, and the interacting genes were subjected to enrichment analysis. To examine the relationship between CETN2 and platinum resistance, gene microarray data and clinical data related to platinum resistance in ovarian cancer were downloaded. The possible signaling pathway of CETN2 was investigated by Gene set enrichment analysis (GSEA). Immune infiltration analysis was performed. Immunohistochemistry (IHC) and quantitative real-time PCR (QRT-PCR) were used to examine the expression of CETN2 in clinical samples in relation to the effectiveness of chemotherapy. The capacity of CETN2 to predict chemotherapy results was proven by receiver operating characteristic (ROC) curves after the construction of two prediction models, the logistic regression model and the decision tree model. The impact of CETN2 on prognosis was examined using the Kaplan-Meier technique.

RESULTS

CETN2 was associated with NER, oxidative phosphorylation (OXPHOS) and cell cycle pathways in ovarian cancer drug-resistant samples. In clinical samples, CETN2 showed its possible correlation with immune infiltration. The protein expression level of CETN2 was significantly higher in platinum-resistant patients than that in platinum-sensitive patients, and the expression level had some predictive value for chemotherapy outcome, and high CETN2 protein expression was associated with poorer progression-free survival.

CONCLUSIONS

CETN2 protein had a significant effect on ovarian cancer platinum sensitivity and prognosis, which may be related to the activation of NER, OXPHOS and cell cycle pathways upon CETN2 upregulation. Further research is necessary to determine the therapeutic application value of CETN2, which may be a new biomarker of chemoresponsiveness.

The Effect of Dual Bioactive Compounds Artemisinin and Metformin Co-loaded in PLGA-PEG Nano-particles on Breast Cancer Cell lines: Potential Apoptotic and Anti-proliferative Action

The most prevalent malignancy among women is breast cancer. Phytochemicals and their derivatives are rapidly being recognized as possible cancer complementary therapies because they can modify signaling pathways that lead to cell cycle control or directly alter cell cycle regulatory molecules. The phytochemicals' poor bioavailability and short half-life make them unsuitable as anticancer drugs. Applying PLGA-PEG NPs improves their solubility and tolerance while also reducing drug adverse effects. According to the findings, combining anti-tumor phytochemicals can be more effective in regulating several signaling pathways linked to tumor cell development. The point of the study was to compare the anti-proliferative impacts of combined artemisinin and metformin on cell cycle arrest and expression of cyclin D1 and apoptotic genes (bcl-2, Bax, survivin, caspase-7, and caspase-3), and also hTERT genes in breast cancer cells. T-47D breast cancer cells were treated with different concentrations of metformin (MET) and artemisinin (ART) co-loaded in PLGA-PEG NPs and free form. The MTT test was applied to assess drug cytotoxicity in T47D cells. The cell cycle distribution was investigated using flow cytometry and the expression levels of cyclin D1, hTERT, Bax, bcl-2, caspase-3, and caspase-7, and survivin genes were then determined using real-time PCR. The findings of the MTT test and flow cytometry revealed that each state was cytotoxic to T47D cells in a time and dose-dependent pattern. Compared to various state of drugs (free and nano state, pure and combination state) Met-Art-PLGA/PEG NPs demonstrated the strongest anti-proliferative impact and considerably inhibited the development of T-47D cells; also, treatment with nano-formulated forms of Met-Art combination resulted in substantial downregulation of hTERT, Bcl-2, cyclin D1, survivin, and upregulation of caspase-3, caspase-7, and Bax, in the cells, as compared to the free forms, as indicated by real-time PCR findings. The findings suggested that combining an ART/MET-loaded PLGA-PEG NP-based therapy for breast cancer could significantly improve treatment effectiveness.

Non-apoptotic cell death in ovarian cancer: Treatment, resistance and prognosis

Ovarian cancer is mostly diagnosed at an advanced stage due to the absence of effective screening methods and specific symptoms. Repeated chemotherapy resistance and recurrence before PARPi are used as maintenance therapies, lead to low survival rates and poor prognosis. Apoptotic cell death plays a crucial role in ovarian cancer, which is proved by current researches. With the ongoing development of targeted therapy, non-apoptotic cell death has shown substantial potential in tumor prevention and treatment, including autophagy, ferroptosis, necroptosis, immunogenic cell death, pyroptosis, alkaliptosis, and other modes of cell death. We systematically reviewed the research progress on the role of non-apoptotic cell death in the onset, development, and outcome of ovarian cancer. This review provides a more theoretical basis for exploring therapeutic targets, reversing drug resistance in refractory ovarian cancer, and establishing risk prediction models that help realize the clinical transformation of vital drugs.

Discovery and repurposing of artemisinin

Malaria is an ancient infectious disease that threatens millions of lives globally even today. The discovery of artemisinin, inspired by traditional Chinese medicine (TCM), has brought in a paradigm shift and been recognized as the “best hope for the treatment of malaria” by World Health Organization. With its high potency and low toxicity, the wide use of artemisinin effectively treats the otherwise drug-resistant parasites and helps many countries, including China, to eventually eradicate malaria. Here, we will first review the initial discovery of artemisinin, an extraordinary journey that was in stark contrast with many drugs in western medicine. We will then discuss how artemisinin and its derivatives could be repurposed to treat cancer, inflammation, immunoregulation-related diseases, and COVID-19. Finally, we will discuss the implications of the “artemisinin story” and how that can better guide the development of TCM today. We believe that artemisinin is just a starting point and TCM will play an even bigger role in healthcare in the 21st century.

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.

Artemisinins in Combating Viral Infections Like SARS-CoV-2, Inflammation and Cancers and Options to Meet Increased Global Demand

Artemisinin is a natural bioactive sesquiterpene lactone containing an unusual endoperoxide 1, 2, 4-trioxane ring. It is derived from the herbal medicinal plant Artemisia annua and is best known for its use in treatment of malaria. However, recent studies also indicate the potential for artemisinin and related compounds, commonly referred to as artemisinins, in combating viral infections, inflammation and certain cancers. Moreover, the different potential modes of action of artemisinins make these compounds also potentially relevant to the challenges the world faces in the COVID-19 pandemic. Initial studies indicate positive effects of artemisinin or Artemisia spp. extracts to combat SARS-CoV-2 infection or COVID-19 related symptoms and WHO-supervised clinical studies on the potential of artemisinins to combat COVID-19 are now in progress. However, implementing multiple potential new uses of artemisinins will require effective solutions to boost production, either by enhancing synthesis in A. annua itself or through biotechnological engineering in alternative biosynthesis platforms. Because of this renewed interest in artemisinin and its derivatives, here we review its modes of action, its potential application in different diseases including COVID-19, its biosynthesis and future options to boost production.

Dihydroartemisinin Suppresses the Tumorigenesis and Cycle Progression of Colorectal Cancer by Targeting CDK1/CCNB1/PLK1 Signaling

Dihydroartemisinin (DHA), a well-known antimalarial drug, has been widely investigated for its antitumor effects in multiple malignancies. However, its effects and regulatory mechanisms in colorectal cancer (CRC) are still unproved. In this study, in vitro experiments including CCK8, EdU, Transwell, and flow cytometry analyses and an in vivo tumorigenesis model were conducted to assess the effects of DHA on the bio-behaviors of CRC cells. Additionally, RNA-seq combined with gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses was used to obtain the targets of DHA, and these were verified by molecular docking, qRT-PCR, and Western blotting. As a result, we found that DHA significantly suppressed the proliferation, DNA synthesis, and invasive capabilities and induced cell apoptosis and cell cycle arrest in HCT116, DLD1, and RKO cells in vitro and in vivo. Further analyses indicated that the targets of DHA were predominantly enriched in cell cycle-associated pathways, including CDK1, CCNB1, and PLK1; and DHA could bind with the CDK1/CCNB1 complex and inhibit the activation of CDK1/CCNB1/PLK1 signaling. Moreover, cucurbitacin E, a specific inhibitor of the CDK1/CCNB1 axis, enhanced the inhibitory effects of DHA on DNA synthesis and colony formation in HCT116 and DLD1 cells. In short, DHA could suppress the tumorigenesis and cycle progression of CRC cells by targeting CDK1/CCNB1/PLK1 signaling.

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.

Progress on the study of the anticancer effects of artesunate

Artesunate (ART) is a derivative of artemisinin that is extracted from the wormwood plant Artemisia annua. ART is an antimalarial drug that has been shown to be safe and effective for clinical use. In addition to its antimalarial properties, ART has been attracting attention over recent years due to its reported inhibitory effects on cancer cell proliferation, invasion and migration. Therefore, ART has a wider range of potential clinical applications than first hypothesized. The aim of the present review was to summarize the latest research progress on the possible anticancer effects of ART, in order to lay a theoretical foundation for the further development of ART as a therapeutic option for cancer.

Mechanisms and Molecular Targets of Artemisinin in Cancer Treatment

The major problems with cancer therapy are drug-induced side effects. There is an urgent need for safe anti-tumor drugs. Artemisinin is a Chinese herbal remedy for malaria with efficacy and safety. However, several studies reported that artemisinin causes neurotoxicity and cardiotoxicity in animal models. Recently, nanostructured drug delivery systems have been designed to improve therapeutic efficacy and reduce toxicity. Artemisinin has been reported to show anticancer properties. The anticancer effects of artemisinin appear to be mediated by inducing cell cycle arrest, promoting ferroptosis and autophagy, inhibiting cell metastasis. Therefore, the review is to concentrate on mechanisms and molecular targets of artemisinin as anti-tumor agents. We believe these will be important topics in realizing the potential of artemisinin and its derivatives as potent anticancer agents.

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.

Progress in Redirecting Antiparasitic Drugs for Cancer Treatment

Drug repurposing is a feasible strategy in developing novel medications. Regarding the cancer field, scientists are continuously making efforts to redirect conventional drugs into cancer treatment. This approach aims at exploring new applications in the existing agents. Antiparasitic medications, including artemisinin derivatives (ARTs), quinine-related compounds, niclosamide, ivermectin, albendazole derivatives, nitazoxanide and pyrimethamine, have been deeply investigated and widely applied in treating various parasitic diseases for a long time. Generally, their pharmacokinetic and pharmacodynamic properties are well understood, while the side effects are roughly acceptable. Scientists noticed that some of these agents have anticancer potentials and explored the underlying mechanisms to achieve drug repurposing. Recent studies show that these agents inhibit cancer progression via multiple interesting ways, inducing ferroptosis induction, autophagy regulation, mitochondrial disturbance, immunoregulation, and metabolic disruption. In this review, we summarize the recent advancement in uncovering antiparasitic drugs' anticancer properties from the perspective of their pharmacological targets. Instead of paying attention to the previously discovered mechanisms, we focus more on newly emerging ones that are worth noticing. While most investigations are focusing on the mechanisms of their antiparasitic effect, more in vivo exploration in clinical trials in the future is necessary. Moreover, we also paid attention to what limits the clinical application of these agents. For some of these agents like ARTs and niclosamide, drug modification, novel delivery system invention, or drug combination are strongly recommended for future exploration.

Recent pharmacological advances in the repurposing of artemisinin drugs

Artemisinins are a family of sesquiterpene lactones originally derived from the sweet wormwood (Artemisia annua). Beyond their well-characterized role as frontline antimalarial drugs, artemisinins have also received increased attention for other potential pharmaceutical effects, which include antiviral, antiparsitic, antifungal, anti-inflammatory, and anticancer activities. With concerted efforts in further preclinical and clinical studies, artemisinin-based drugs have the potential to be viable treatments for a great variety of human diseases. Here, we provide a comprehensive update on recent reports of pharmacological actions and applications of artemisinins outside of their better-known antimalarial role and highlight their potential therapeutic viability for various diseases.

Dihydroartemisinin as a Sensitizing Agent in Cancer Therapies

Cancer is one of the major threats to human health. Although humans have struggled with cancer for decades, the efficacy of treatments for most tumors is still very limited. Dihydroartemisinin (DHA) is a derivative of artemisinin, a first-line antimalarial drug originally developed in China. Beyond the anti-malarial effect, DHA has also been reported to show anti-inflammatory, anti-parasitosis, and immune-modulating properties in vitro and in vivo. Furthermore, an increasing number of studies report that DHA possesses anticancer activities on a wide range of cancer types both in vitro and in vivo, as well as enhances the efficacy of chemotherapy, targeted therapy, and even radiotherapy. However, the mechanisms of DHA on different tumors differ in various ways. In this review, we intend to summarize how DHA sensitizes cancer cells to anti-cancer therapies, highlight its molecular mechanisms and pharmacological effects in vitro and in vivo as well as in current clinical trials, and discuss potential issues concerning DHA. Hopefully, more attention will be paid to DHA as a sensitizer for cancer therapy in the future.

Repurposing Quinoline and Artemisinin Antimalarials as Therapeutics for SARS-CoV-2: Rationale and Implications

The coronavirus disease-2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected more than 116 million individuals globally and resulted in over 2.5 million deaths since the first report in December 2019. For most of this time, healthcare professionals have had few tools at their disposal. In December 2020, several vaccines that were shown to be highly effective have been granted emergency use authorization (EUA). Despite these remarkable breakthroughs, challenges include vaccine roll-out and implementation, in addition to deeply entrenched antivaccination viewpoints. While vaccines will prevent disease occurrence, infected individuals still need treatment options, and repurposing drugs circumvents the lengthy and costly process of drug development. SARS-CoV-2, like many other enveloped viruses, require the action of host proteases for entry. In addition, this novel virus employs a unique method of cell exit of deacidified lysosomes and exocytosis. Thus, inhibitors of lysosomes or other players in this pathway are good candidates to target SARS-CoV-2. Chemical compounds in the quinoline class are known to be lysomotropic and perturb pH levels. A large number of quinolines are FDA-approved for treatment of inflammatory diseases and antimalarials. Artemisinins are another class of drugs that have been demonstrated to be safe for use in humans and are widely utilized as antimalarials. In this Review, we discuss the use of antimalarial drugs in the class of quinolines and artemisinins, which have been shown to be effective against SARS-CoV-2 in vitro and in vivo, and provide a rationale in employing quinolines as treatment of SARS-CoV-2 in clinical settings.

Therapeutic Potentials and Mechanisms of Artemisinin and its Derivatives for Tumorigenesis and Metastasis

BACKGROUND

Tumor recurrence and metastasis are still leading causes of cancer mortality worldwide. The influence of traditional treatment strategies against metastatic tumors may still be limited. To search for novel and powerful agents against tumors has become a major research focus. In this study, Artemisinin (ARM), a natural compound isolated from herbs, Artemisia annua L., proceeding from drug repurposing methods, attracts more attention due to its good efficacy and tolerance in antimalarial practices, as well as newly confirmed anticancer activity.

METHODS

We have searched and reviewed the literatures about ARM and its derivatives (ARMs) for cancer using keywords "artemisinin" until May 2019.

RESULTS

In preclinical studies, ARMs can induce cell cycle arrest and cell death by apoptosis etc., to inhibit the progression of tumors, and suppress EMT and angiogenesis to inhibit the metastasis of tumors. Notably, the complex relationships of ARMs and autophagy are worth exploring. Inspired by the limitations of its antimalarial applications and the mechanical studies of artemisinin and cancer, people are also committed to develop safer and more potent ARM-based modified compounds (ARMs) or combination therapy, such as artemisinin dimers/ trimers, artemisinin-derived hybrids. Some clinical trials support artemisinins as promising candidates for cancer therapy.

CONCLUSION

ARMs show potent therapeutic potentials against carcinoma including metastatic tumors. Novel compounds derived from artemisinin and relevant combination therapies are supposed to be promising treatment strategies for tumors, as the important future research directions.

Dihydroartemisinin: A Potential Natural Anticancer Drug

Dihydroartemisinin (DHA) is an active metabolite of artemisinin and its derivatives (ARTs), and it is an effective clinical drug widely used to treat malaria. Recently, the anticancer activity of DHA has attracted increasing attention. Nevertheless, there is no systematic summary on the anticancer effects of DHA. Notably, studies have shown that DHA exerts anticancer effects through various molecular mechanisms, such as inhibiting proliferation, inducing apoptosis, inhibiting tumor metastasis and angiogenesis, promoting immune function, inducing autophagy and endoplasmic reticulum (ER) stress. In this review, we comprehensively summarized the latest progress regarding the anticancer activities of DHA in cancer. Importantly, the underlying anticancer molecular mechanisms and pharmacological effects of DHA in vitro and in vivo are the focus of our attention. Interestingly, new methods to improve the solubility and bioavailability of DHA are discussed, which greatly enhance its anticancer efficacy. Remarkably, DHA has synergistic anti-tumor effects with a variety of clinical drugs, and preclinical and clinical studies provide stronger evidence of its anticancer potential. Moreover, this article also gives suggestions for further research on the anticancer effects of DHA. Thus, we hope to provide a strong theoretical support for DHA as an anticancer drug.

Development of Potential Antitumor Agents from the Scaffolds of Plant-Derived Terpenoid Lactones

Naturally occurring terpenoid lactones and their synthetic derivatives have attracted increasing interest for their promising antitumor activity and potential utilization in the discovery and design of new antitumor agents. In the present perspective article, selected plant-derived five-membered γ-lactones and six-membered δ-lactones that occur with terpenoid scaffolds are reviewed, with their structures, cancer cell line cytotoxicity and in vivo antitumor activity, structure-activity relationships, mechanism of action, and the potential for developing cancer chemotherapeutic agents discussed in each case. The compounds presented include artemisinin (ART, 1), parthenolide (PTL, 2), thapsigargin (TPG, 3), andrographolide (AGL, 4), ginkgolide B (GKL B, 5), jolkinolide B (JKL B, 6), nagilactone E (NGL E, 7), triptolide (TPL, 8), bruceantin (BRC, 9), dichapetalin A (DCT A, 10), and limonin (LMN, 11), and their naturally occurring analogues and synthetic derivatives. It is hoped that this contribution will be supportive of the future development of additional efficacious anticancer agents derived from natural products.

Artesunate Impairs Growth in Cisplatin-Resistant Bladder Cancer Cells by Cell Cycle Arrest, Apoptosis and Autophagy Induction

Cisplatin, which induces DNA damage, is standard chemotherapy for advanced bladder cancer (BCa). However, efficacy is limited due to resistance development. Since artesunate (ART), a derivative of artemisinin originating from Traditional Chinese Medicine, has been shown to exhibit anti-tumor activity, and to inhibit DNA damage repair, the impact of artesunate on cisplatin-resistant BCa was evaluated. Cisplatin-sensitive (parental) and cisplatin-resistant BCa cells, RT4, RT112, T24, and TCCSup, were treated with ART (1-100 µM). Cell growth, proliferation, and cell cycle phases were investigated, as were apoptosis, necrosis, ferroptosis, autophagy, metabolic activity, and protein expression. Exposure to ART induced a time- and dose-dependent significant inhibition of tumor cell growth and proliferation of parental and cisplatin-resistant BCa cells. This inhibition was accompanied by a G0/G1 phase arrest and modulation of cell cycle regulating proteins. ART induced apoptos is by enhancing DNA damage, especially in the resistant cells. ART did not induce ferroptosis, but led to a disturbance of mitochondrial respiration and ATP generation. This impairment correlated with autophagy accompanied by a decrease in LC3B-I and an increase in LC3B-II. Since ART significantly inhibits proliferative and metabolic aspects of cisplatin-sensitive and cisplatin-resistant BCa cells, it may hold potential in treating advanced and therapy-resistant BCa.

Artemisinin Attenuated Atherosclerosis in High-Fat Diet-Fed ApoE-/- Mice by Promoting Macrophage Autophagy Through the AMPK/mTOR/ULK1 Pathway

Artemisinin is an endoperoxide sesquiterpene lactone from Artemisia annua L with multiple beneficial effects, including anti-inflammation, antioxidant, and vascular protection. Recent studies have found that inflammation along with autophagy deficiency in macrophages is the possible reason for foam cell accumulation in the intima, which leads to atherosclerotic plaque formation. The primary aims of this study were to explore the inhibiting effect of artemisinin on atherosclerosis in high-fat diet-fed ApoE mice and investigate the probable mechanism. Artemisinin (50 and 100 mg/kg, intragastric administration) treatment effectively inhibited foamy macrophage transformation and decreased atherosclerotic plaque formation in atherosclerotic mice. Moreover, artemisinin promoted AMP-activated protein kinase (AMPK) activation, inhibited mammalian target of rapamycin (mTOR) and uncoordinated-51-like kinase 1 (ULK1) phosphorylation, and increased LC-3II accumulation and P62 degradation, thereby enhancing macrophage autophagy. Besides, the inhibiting effect of artemisinin on mTOR and ULK1 phosphorylation could be abrogated by AMPK knockdown, suggesting AMPK was the essential target of artemisinin on promoting macrophage autophagy. Our study indicated that artemisinin alleviated atherosclerotic lesions by accelerating macrophage autophagy through the AMPK/mTOR/ULK1 pathway.

Pristine Cu-MOF Induces Mitotic Catastrophe and Alterations of Gene Expression and Cytoskeleton in Ovarian Cancer Cells

Metals-organic frameworks (MOFs) have been widely explored in biomedicine, mostly in drug delivery, biosensing, and bioimaging due to their large surface area, tunable porosity, readily chemical functionalization, and good biocompatibility. However, the underlining cellular mechanisms controlling the process for MOF cytotoxicity remains almost completely unknown. Here, we demonstrate that pristine Cu-MOF without any loaded drug selectively inhibited ovarian cancer mainly through promoting tubulin polymerization and destroying the cell actin cytoskeleton (F-actin) to trigger the mitotic catastrophe, accompanying by conventional programmed cell death. To our knowledge, this is the first report claiming that mitotic catastrophe may be an explaining mechanism of MOF cytotoxicity. Cu-MOF with an intrinsic protease-like activity also hydrolyzed cellular cytoskeleton proteins (F-actin). The RNA sequencing data indicated the differential expressional mRNA of cell proliferation and actin cytoskeleton (ACTA2, ACTN3, FSCN2, and SCIN) and mitotic spindles (PLK1 and TPX2) related genes. We found that Cu-MOF as a promising candidate in the disruption of cellular cytoskeleton and the change of the gene expression could be actin altering and antimitotic agents against cancer cells, allowing for fundamental biological and biophysical studies of MOFs.

Dihydroartemisinin suppresses bladder cancer cell invasion and migration by regulating KDM3A and p21

Emerging evidences have shown that Dihydroartemisinin (DHA), used in malaria treatment, possess anti-cancer activity. However, the study of its potential functional roles and the anti-cancer mechanisms in bladder cancer is limited. We performed this study to elucidate the influence of DHA in the biological behavior of bladder cancer cells and tried to explore the molecular mechanism. The results of CCK-8 assay showed that DHA significantly inhibited bladder cancer cell 5637, UMUC3 and T24 proliferation and the inhibitory effect is dose- and time- dependent. Further mechanism study showed that DHA performed its function via down-regulating the expression of histone demethylase KDM3A and inducing p21 expression. Moreover, wound healing and transwell migration/invasion assays revealed that DHA inhibited the ability of migration and metastasis in bladder cancer cell line T24. Finally, flow cytometry and colony formation assays demonstrated that DHA significantly promoted apoptosis of T24 cells and suppressed tumorigenesis as expected. Taken together, our study identifies the anti-cancer capacity of DHA in bladder cancer and explores the underlying mechanism.

Artesunate inhibits the mevalonate pathway and promotes glioma cell senescence

Glioma is a common brain malignancy for which new drug development is urgently needed because of radiotherapy and drug resistance. Recent studies have demonstrated that artemisinin (ARS) compounds can display antiglioma activity, but the mechanisms are poorly understood. Using cell lines and mouse models, we investigated the effects of the most soluble ARS analogue artesunate (ART) on glioma cell growth, migration, distant seeding and senescence and elucidated the underlying mechanisms. Artemisinin effectively inhibited glioma cell growth, migration and distant seeding. Further investigation of the mechanisms showed that ART can influence glioma cell metabolism by affecting the nuclear localization of SREBP2 (sterol regulatory element‐binding protein 2) and the expression of its target gene HMGCR (3‐hydroxy‐3‐methylglutaryl coenzyme A reductase), the rate‐limiting enzyme of the mevalonate (MVA) pathway. Moreover, ART affected the interaction between SREBP2 and P53 and restored the expression of P21 in cells expressing wild‐type P53, thus playing a key role in cell senescence induction. In conclusion, our study demonstrated the new therapeutic potential of ART in glioma cells and showed the novel anticancer mechanisms of ARS compounds of regulating MVA metabolism and cell senescence.

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

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

Artemisinin and its derivatives prevent Helicobacter pylori-induced gastric carcinogenesis via inhibition of NF-κB signaling

BACKGROUND

Gastric cancer has a high morbidity and is a leading cause of cancer-related mortality worldwide. Helicobacter pylori (H. pylori) infection is commonly found in the early stage of gastric cancer pathogenesis, which induces chronic gastritis. Artemisinin (ART) and its derivatives (ARTS, artesunate and DHA, dihydroartemisinin), a new class of potent antimalarials, have been reported to exert both preventive and anti-gastric cancer effects. However, the underlying mechanisms of the chemopreventive effects of ART and its derivatives in H. pylori infection induced-gastric cancer are not fully elucidated.

PURPOSE

We investigated the effects of H. pylori infection in gastric cancer; and the preventive mechanisms of ART, ARTS and DHA.

METHODS

The H. pylori growth was determined by the broth macro-dilution method, and its adhesion to gastric cancer cells was evaluated by using the urease assay. The protein and mRNA levels, reactive oxygen species (ROS) production, as well as the production of inflammatory cytokines were evaluated by Western blot, real-time PCR, flow cytometry and ELISA, respectively. Moreover, an in vivo MNU (N-methyl-N-nitroso-urea) and H. pylori-induced gastric adenocarcinoma mouse model was established for the investigation of the cancer preventive effects of ART and its derivaties, and the underlying mechanisms of action.

RESULTS

ART, DHA and ARTS inhibited the growth of H. pylori and gastric cancer cells,suppressed H. pylori adhesion to the gastric cancer cells, and reduced the H. pylori-enhanced ROS production. Moreover, ART, DHA and ARTS significantly reduced tumor incidence, number of tumor nodules and tumor size in the mouse model. Among these three compounds, DHA exerted the most potent chemopreventive effect. Mechanistic studies showed that ART and its derivatives potently inhibited the NF-κB activation.

CONCLUSION

ART, DHA and ARTS have potent preventive effects in H. pylori-induced gastric carcinogenesis. These effects are, at least in part, attributed to the inhibition of NF-κB signaling pathway. Our findings provide a molecular justification of using ART and its derivatives for the prevention and treatment of gastric cancer.

Targeting autophagy enhances the anticancer effect of artemisinin and its derivatives

Artemisinin and its derivatives, with their outstanding clinical efficacy and safety, represent the most effective and impactful antimalarial drugs. Apart from its antimalarial effect, artemisinin has also been shown to exhibit selective anticancer properties against multiple cancer types both in vitro and in vivo. Specifically, our previous studies highlighted the therapeutic effects of artemisinin on autophagy regulation. Autophagy is a well-conserved degradative process that recycles cytoplasmic contents and organelles in lysosomes to maintain cellular homeostasis. The deregulation of autophagy is often observed in cancer cells, where it contributes to tumor adaptation to nutrient-deficient tumor microenvironments. This review discusses recent advances in the anticancer properties of artemisinin and its derivatives via their regulation of autophagy, mitophagy, and ferritinophagy. In particular, we will discuss the mechanisms of artemisinin activation in cancer and novel findings regarding the role of artemisinin in regulating autophagy, which involves changes in multiple signaling pathways. More importantly, with increasing failure rates and the high cost of the development of novel anticancer drugs, the strategy of repurposing traditional therapeutic Chinese medicinal agents such as artemisinin to treat cancer provides a more attractive alternative. We believe that the topics covered here will be important in demonstrating the potential of artemisinin and its derivatives as safe and potent anticancer agents.