Preclinical Efficacy and Safety Assessment of Artemisinin-Chemotherapeutic Agent Conjugates for Ovarian Cancer

Preparation and in vitro evaluation of cell adhesion and long-term proliferation of stem cells cultured on silibinin co-embedded PLGA/Collagen electrospun composite nanofibers

The present research aims to evaluate the efficacy of Silibinin-loaded mesoporous silica nanoparticles (Sil@MSNs) immobilized into polylactic-co-glycolic acid/Collagen (PLGA/Col) nanofibers on the in vitro proliferation of adipose-derived stem cells (ASCs) and cellular senescence. Here, the fabricated electrospun PLGA/Col composite scaffolds were coated with Sil@MSNs and their physicochemical properties were examined by FTIR, FE-SEM, and TGA. The growth, viability and proliferation of ASCs were investigated using various biological assays including PicoGreen, MTT, and RT-PCR after 21 days. The proliferation and adhesion of ASCs were supported by the biological and mechanical characteristics of the Sil@MSNs PLGA/Col composite scaffolds, according to FE- SEM. PicoGreen and cytotoxicity analysis showed an increase in the rate of proliferation and metabolic activity of hADSCs after 14 and 21 days, confirming the initial and controlled release of Sil from nanofibers. Gene expression analysis further confirmed the increased expression of stemness markers as well as hTERT and telomerase in ASCs seeded on Sil@MSNs PLGA/Col nanofibers compared to the control group. Ultimately, the findings of the present study introduced Sil@MSNs PLGA/Col composite scaffolds as an efficient platform for long-term proliferation of ASCs in tissue engineering.

Facilitated Drug Repurposing with Artemisinin-Derived PROTACs: Unveiling PCLAF as a Therapeutic Target

Artemisinin, a prominent anti-malaria drug, is being investigated for its potential as a repurposed cancer treatment. However, its effectiveness in tumor cell lines remains limited, and its mechanism of action is unclear. To make more progress, the PROteolysis-TArgeting chimera (PROTAC) technique has been applied to design and synthesize novel artemisinin derivatives in this study. Among them, AD4, the most potent compound, exhibited an IC50 value of 50.6 nM in RS4;11 cells, over 12-fold better than that of its parent compound, SM1044. This was supported by prolonged survival of RS4;11-transplanted NOD/SCID mice. Meanwhile, AD4 effectively degraded PCLAF in RS4;11 cells and thus activated the p21/Rb axis to exert antitumor activity by directly targeting PCLAF. The discovery of AD4 highlights the great potential of using PROTACs to improve the efficacy of natural products, identify therapeutic targets, and facilitate drug repurposing. This opens a promising avenue for transforming other natural products into effective therapies.

Molecular Hybridization as a Strategy for Developing Artemisinin-Derived Anticancer Candidates

Artemisinin is a natural compound extracted from Artemisia species belonging to the Asteraceae family. Currently, artemisinin and its derivatives are considered among the most significant small-molecule antimalarial drugs. Artemisinin and its derivatives have also been shown to possess selective anticancer properties, however, there are several limitations and gaps in knowledge that retard their repurposing as effective anticancer agents. Hybridization resulting from a covalent combination of artemisinin with one or more active pharmacophores has emerged as a promising approach to overcome several issues. The variety of hybridization partners allows improvement in artemisinin activity by tuning the ability of conjugated artemisinin to interact with various molecule targets involved in multiple biological pathways. This review highlights the current scenario of artemisinin-derived hybrids with potential anticancer activity. The synthetic approaches to achieve the corresponding hybrids and the structure-activity relationships are discussed to facilitate further rational design of more effective candidates.

GPX4 inhibition synergistically boosts mitochondria targeting nanoartemisinin-induced apoptosis/ferroptosis combination cancer therapy

Artemisinin, originally used for its antimalarial activity, has received much attention in recent years for cancer therapy. The anticancer mechanisms of artemisinin are complicated and debatable. Challenges in the delivery of artemisinin also persist because the anticancer effect of artemisinin alone is often not satisfactory when used with traditional nanocarriers. We herein report the mitochondrial delivery of artemisinin with extremely high anticancer capacity. The action mode of artemisinin in the mitochondria of cancer cells includes heme-participating and oxygen-independent conversion of artemisinin into a carbon-centered radical, which is partly converted into ROS in the presence of molecular oxygen. We reveal that artemisinin alone in the mitochondria can induce strong cancer cell apoptosis. In addition, due to the weak inhibition of GPX4 activity by artemisinin, weak ferroptosis is also observed. We further discover that GPX4 activity in MCF-7 cells is greatly inhibited by RSL3 to synergistically enhance the anticancer capacity of artemisinin via enhancing ferroptosis. The synergistic anticancer activity of artemisinin and RSL3 in the mitochondria not only improves cancer cell-killing ability, but also inhibits the re-proliferation of residual cancer cells. This study provides a new insight into developing highly efficient and practical artemisinin nanomedicines for cancer therapy.

Metal-organic framework-encapsulated dihydroartemisinin nanoparticles induces apoptotic cell death in ovarian cancer by blocking ROMO1-mediated ROS production

Dihydroartemisinin (DHA), a natural product derived from the herbal medicine Artemisia annua, is recently used as a novel anti-cancer agent. However, some intrinsic disadvantages limit its potential for clinical management of cancer patients, such as poor water solubility and low bioavailability. Nowadays, the nanoscale drug delivery system emerges as a hopeful platform for improve the anti-cancer treatment. Accordingly, a metal-organic framework (MOF) based on zeolitic imidazolate framework-8 was designed and synthesized to carry DHA in the core (ZIF-DHA). Contrast with free DHA, these prepared ZIF-DHA nanoparticles (NPs) displayed preferable anti-tumor therapeutic activity in several ovarian cancer cells accompanied with suppressed production of cellular reactive oxygen species (ROS) and induced apoptotic cell death. 4D-FastDIA-based mass spectrometry technology indicated that down-regulated reactive oxygen species modulator 1 (ROMO1) might be regarded as potential therapeutic targets for ZIF-DHA NPs. Overexpression of ROMO1 in ovarian cancer cells significantly reversed the cellular ROS-generation induced by ZIF-DHA, as well as the pro-apoptosis effects. Taken together, our study elucidated and highlighted the potential of zeolitic imidazolate framework-8-based MOF to improve the activity of DHA to treat ovarian cancer. Our findings suggested that these prepared ZIF-DHA NPs could be an attractive therapeutic strategy for ovarian cancer.

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.

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

A comprehensive overview of Artemisinin and its derivatives as anticancer agents

Artemisinin is the crucial ingredient of artemisia annua, a traditional Chinese medicine used for the therapy of malaria in China for hundreds of years. In recent years, the anticancer properties of artemisinin and its derivatives have also been reported. This review has summarized the research and development of artemisinin and its derivatives as anticancer agents, which included both natural and synthetic monomers as well as their dimers. In addition, it highlights the antitumor effects of artemisinin and its derivatives after site-modification or after transformation to a nano-delivery system. Moreover, we have further explored their potential mechanisms of action and also discussed the clinical trials of ARTs used to treat cancer, which will facilitate in further development of novel anticancer drugs based on the scaffold of artemisinin.

Role of Plant-Derived Active Constituents in Cancer Treatment and Their Mechanisms of Action

Despite significant technological advancements in conventional therapies, cancer remains one of the main causes of death worldwide. Although substantial progress has been made in the control and treatment of cancer, several limitations still exist, and there is scope for further advancements. Several adverse effects are associated with modern chemotherapy that hinder cancer treatment and lead to other critical disorders. Since ancient times, plant-based medicines have been employed in clinical practice and have yielded good results with few side effects. The modern research system and advanced screening techniques for plants’ bioactive constituents have enabled phytochemical discovery for the prevention and treatment of challenging diseases such as cancer. Phytochemicals such as vincristine, vinblastine, paclitaxel, curcumin, colchicine, and lycopene have shown promising anticancer effects. Discovery of more plant-derived bioactive compounds should be encouraged via the exploitation of advanced and innovative research techniques, to prevent and treat advanced-stage cancers without causing significant adverse effects. This review highlights numerous plant-derived bioactive molecules that have shown potential as anticancer agents and their probable mechanisms of action and provides an overview of in vitro, in vivo and clinical trial studies on anticancer phytochemicals.

Artemisinin and Derivatives-Based Hybrid Compounds: Promising Therapeutics for the Treatment of Cancer and Malaria

Cancer and malaria are major health conditions around the world despite many strategies and therapeutics available for their treatment. The most used strategy for the treatment of these diseases is the administration of therapeutic drugs, which suffer from several shortcomings. Some of the pharmacological limitations associated with these drugs are multi-drug resistance, drug toxicity, poor biocompatibility and bioavailability, and poor water solubility. The currently ongoing preclinical studies have demonstrated that combination therapy is a potent approach that can overcome some of the aforementioned limitations. Artemisinin and its derivatives have been reported to exhibit potent efficacy as anticancer and antimalarial agents. This review reports hybrid compounds containing artemisinin scaffolds and their derivatives with promising therapeutic effects for the treatment of cancer and malaria.

Immunomolecular evaluation of dihydroartemisinin effects on apoptosis in chronic lymphocytic leukemia cell lines

INTRODUCTION

Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, has recently shown to induce apoptosis in many types of cancer cells. In this study, we aimed to determine the effects of DHA on apoptosis in human chronic lymphocytic leukemia (CLL) cell lines.

METHODS

The cells were treated separately and combined by DHA and Fludurabine (FLU) during 24, 48 and 72 hours. The cell viabilities determined by XTT method. Following separate and combined treatment of IC50 concentrations of DHA and FLU to the cells during 24 hours, the cells were analyzed by flow cytometry to determine the effects on apopotis staining with AnnexinV FITC and PI. mRNA and protein expression levels of TCTP, Mcl-1, Bcl-2, Bax and Caspase-3 were analyzed to find out the molecular mechanisms of apoptosis by using quantitative real-time PCR and flow cytometric methods.

RESULTS

Treatment with DHA alone or in combination with FLU induced apoptosis in a dose dependent manner in CLL cells. DHA alone was more effective than FLU alone or combined treatment with DHA and FLU. Our results suggest that Bcl-2 protein family member Bax was active in the apoptotic response of CLL cells after DHA treatment. Moreover, the apoptotic response induced by DHA was independent from the p53 mutation status of the CLL cells.

CONCLUSION

DHA might be a potential anti-cancer therapeutic for CLL.

Synthesis and biological activities of novel mitochondria-targeted artemisinin ester derivatives

A series of novel artemisinin ester derivatives were designed and synthesized for targeting mitochondria. Cytotoxicity against SMMC-7721, HepG2, OVCAR3, A549 and J82 cancer cell lines was evaluated. Compound 2c (IC₅₀ = 3.0 μM) was the most potent anti-proliferative molecule against the OVCAR3 cells with low cytotoxicity in normal HUVEC cells. The mechanism of action of compound 2c was further investigated by analyzing cell apoptosis, mitochondrial membrane potential (Δψm) and intracellular ROS generation. The results indicated that compound 2c targeted mitochondria and induced cell apoptosis. ROS and heme attributed to the cytotoxicity and cell apoptosis of compound 2c. These promising findings indicated the compound 2c could serve as a great candidate against ovarian cancer for further investigation.

TGFβ signaling networks in ovarian cancer progression and plasticity

Epithelial ovarian cancer (EOC) is a leading cause of cancer-related death in women. Late-stage diagnosis with significant tumor burden, accompanied by recurrence and chemotherapy resistance, contributes to this poor prognosis. These morbidities are known to be tied to events associated with epithelial-mesenchymal transition (EMT) in cancer. During EMT, localized tumor cells alter their polarity, cell-cell junctions, cell-matrix interactions, acquire motility and invasiveness and an exaggerated potential for metastatic spread. Key triggers for EMT include the Transforming Growth Factor-β (TGFβ) family of growth factors which are actively produced by a wide array of cell types within a specific tumor and metastatic environment. Although TGFβ can act as either a tumor suppressor or promoter in cancer, TGFβ exhibits its pro-tumorigenic functions at least in part via EMT. TGFβ regulates EMT both at the transcriptional and post-transcriptional levels as outlined here. Despite recent advances in TGFβ based therapeutics, limited progress has been seen for ovarian cancers that are in much need of new therapeutic strategies. Here, we summarize and discuss several recent insights into the underlying signaling mechanisms of the TGFβ isoforms in EMT in the unique metastatic environment of EOCs and the current therapeutic interventions that may be relevant.

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.

Structural optimization and biological evaluation for novel artemisinin derivatives against liver and ovarian cancers

An increasing number of artemisinin (ARS) and its derivatives have been reported for their potential therapeutic value of human cancer. However, their therapeutic potencies are limited owing to their poor pharmacokinetic profiles. Our previous studies showed that a lead compound ARS4 originated from incorporating the pharmacophore of the approved chemotherapeutic agent melphalan into the basic skeleton of artemisinin with a succinic linker exhibited an excellent toxicity to human ovarian cancer cells and low cytotoxicity to normal cells. The mechanism studies demonstrated that it inhibited the growth and proliferation of ovarian cancer cells and resulted in S-phase arrest, apoptosis and inhibition of migration. Meanwhile, it exhibited excellent antitumor activities in animal models. Herein, further structure optimization for this lead compound ARS4 was performed and nineteen novel derivatives were designed and synthesized. Among them, compounds 10-12, 15, 16, 18 and 19 demonstrated powerful cytotoxic effects against human liver cancer and ovarian cancer cell lines, with their IC_50s below 0.86 μM against Hep3B and A2780 cell lines, which are superior to that of ARS4. Four compounds (11, 15, 16 and 18) were selected to further evaluate their antitumor activities in in vitro and in vivo ovarian and liver cancer models, the results indicated that compound 18 exhibited the best therapeutic effect, not only effectively inhibited the growth of 7404 xenograft and Huh7 xenograft, but also presented a good dose-dependent inhibition toward the growth of A2780 xenograft. Overall, based on these positive results, these novel chemical structures may provide a new inspiration for the discovery of novel antitumor agents originated from artemisinin scaffolds.

Artemisinins as Anticancer Drugs: Novel Therapeutic Approaches, Molecular Mechanisms, and Clinical Trials

Artemisinin and its derivatives have shown broad-spectrum antitumor activities in vitro and in vivo. Furthermore, outcomes from a limited number of clinical trials provide encouraging evidence for their excellent antitumor activities. However, some problems such as poor solubility, toxicity and controversial mechanisms of action hamper their use as effective antitumor agents in the clinic. In order to accelerate the use of ARTs in the clinic, researchers have recently developed novel therapeutic approaches including developing novel derivatives, manufacturing novel nano-formulations, and combining ARTs with other drugs for cancer therapy. The related mechanisms of action were explored. This review describes ARTs used to induce non-apoptotic cell death containing oncosis, autophagy, and ferroptosis. Moreover, it highlights the ARTs-caused effects on cancer metabolism, immunosuppression and cancer stem cells and discusses clinical trials of ARTs used to treat cancer. The review provides additional insight into the molecular mechanism of action of ARTs and their considerable clinical potential.

The potential of artemisinins as anti-obesity agents via modulating the immune system

Artemisinin and its derivatives are the most effective antimalarial drugs. Besides anti-malarial activity, artemisinin and its derivatives have displayed wide-spectrum bioactivities such as anti-parasite, anti-tumor, and anti-obesity effects. Obesity is an epidemic worldwide which is a big threat to human health, but there are only a few approved anti-obesity drugs in the world. Also, these drugs are efficient to limited patients partly because their safety and efficacy are questioned. Anti-inflammatory therapies may be valuable in obesity treatment since growing evidence shows chronic metabolic inflammation is implicated in metabolic disease pathogenesis. As artemisinin and its derivatives display effective anti-inflammatory and immunoregulatory properties with less toxicity, it provides an insight for novel drug development in obesity therapeutic strategies via immune-regulatory mechanisms. In this review, the potential of artemisinin and its derivatives to treat various metabolic diseases such as obesity and diabetes is discussed.

Dissecting pharmacological effects of chloroquine in cancer treatment: interference with inflammatory signaling pathways

Chloroquines are 4-aminoquinoline-based drugs mainly used to treat malaria. At pharmacological concentrations, they have significant effects on tissue homeostasis, targeting diverse signaling pathways in mammalian cells. A key target pathway is autophagy, which regulates macromolecule turnover in the cell. In addition to affecting cellular metabolism and bioenergetic flow equilibrium, autophagy plays a pivotal role at the interface between inflammation and cancer progression. Chloroquines consequently have critical effects in tissue metabolic activity and importantly, in key functions of the immune system. In this article, we will review the work addressing the role of chloroquines in the homeostasis of mammalian tissue, and the potential strengths and weaknesses concerning their use in cancer therapy.

Fourier Transform Infrared Spectroscopy Monitoring of Dihydroartemisinin-Induced Growth Inhibition in Ovarian Cancer Cells and Normal Ovarian Surface Epithelial Cells

Purpose

Ovarian cancer is the most lethal of gynecological malignancies. Dihydroartemisinin (DHA), a derivative of artemisinin (ARS), has profound effects against human tumors. The aim of this study was to provide a convenient, cost-efficient technique, Fourier transform infrared (FTIR) spectroscopy, to monitor and evaluate responses to DHA-induced growth inhibition of ovarian cancer cells.

Methods

Cell growth and viability and the 50% inhibitory concentration (IC50) of DHA were assessed by the MTT assay. FTIR spectroscopy was used to monitor cells following DHA treatment, and data were analyzed by OMNIC 8.0 software.

Results

DHA can decrease the viability of ovarian cancer cells and normal cells, but cancer cells were more sensitive to this drug than normal cells. Spectral differences were observed between cells with or without DHA treatment. In particular, an increase in the amount of lipids and nucleic acids was observed. The band intensity ratio of 1454/1400, and the intensity of the band 1741 cm⁻¹ increased, indicating stronger absorption after DHA treatment. Moreover, the differences were larger for the cell lines that were more sensitive to DHA.

Conclusion

The spectral features provided information about important molecular characteristics of the cells in response to chemicals. These findings demonstrated the possible use of FTIR spectroscopy to evaluate DHA-induced growth inhibition effects in ovarian cancer cells and provided a promising new tool for monitoring cell growth and the effects of antitumor drugs in the clinic in the future.

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.

Artemisinin-Based Smart Nanomedicines with Self-Supply of Ferrous Ion to Enhance Oxidative Stress for Specific and Efficient Cancer Treatment

Though abundant researches report that artemisinin could inhibit cancer cell growth via generating toxic reactive oxygen species (ROS), the therapeutic efficiency of artemisinin for cancer treatment is still limited owing to the insufficient intracellular ferrous ion and defensive effect of intracellular glutathione. Herein, we report a cathepsin B-controllable smart nanomedicine based on the structural and pharmacodynamic characteristics of artemisinin, which employed transferrin-peptide-modified mesoporous silica to codeliver artemisinin and buthionine-sulfoximine, a glutathione scavenger, into cancer cells. As a gatekeeper, the transferrin-peptide can not only target the cancer cells but also supply the extra ferrous iron to catalyze artemisinin to produce excessive ROS to kill cancer cells efficiently. Once the designed nanomedicine attack into lysosome of tumor cells, the cargos of nanomedicine can be released in the presence of cathepsin B to immediately activate self-amplification of oxidative stress by simultaneously elevating the levels of ROS and weakening the levels of glutathione. We anticipate that this rational design strategy provides innovative opportunities for artemisinin in the clinical application of cancer.

Artemisinin and its derivatives; ancient tradition inspiring the latest therapeutic approaches against malaria

Artemisinin (ART) is an endoperoxide sesquiterpene lactone, commonly used in the treatment of malaria. Although it was isolated from Artemisia annua L., a plant widely applied in Chinese Traditional Medicine, its mechanism of action remains uncertain and its clinical use is still limited due to its low solubility, its poor bioavailability and short in vivo half-life. Over time, several studies have been aimed towards the discovery of potent ART derivatives that could overcome clinical drawbacks. In this review, we focus on the multifaced aspects of ART and on the efforts spent to improve its pharmacological profile that so far culminated in the discovery of more effective drugs. Lastly, we outline the new perspectives in the ART-derivatives scenario.

Artemisinin induced reversal of EMT affects the molecular biological activity of ovarian cancer SKOV3 cell lines

Accumulating evidence suggests that celecoxib and artemisinin could mediate ovarian cancer development and metastasis. The present study investigated the effects of celecoxib and artemisinin on the epithelial-mesenchymal transition (EMT) characteristics of the human ovarian epithelial adenocarcinoma cell line, SKOV3. SKOV3 cells were incubated with celecoxib (10 µM) for different periods of time to establish an EMT cell model. Subsequently, artemisinin (20, 40 and 80 µM) was used to establish a cell model of the reverse process, mesenchymal-epithelial transition (MET). Cell proliferation, metastasis, invasiveness and the expression of vimentin and E-cadherin were measured using Cell Counting Kit-8, wound healing assay, western blotting, flow cytometry and immunofluorescence. The EMT cell model exhibited enhanced proliferative capacity, increased migration, increased vimentin expression and decreased E-cadherin expression. By contrast, artemisinin decreased proliferative capacity, decreased migration, decreased vimentin expression and increased E-cadherin expression of EMT model cells, indicating that MET was induced. These results demonstrated that artemisinin may reverse celecoxib-induced epithelial-mesenchymal transition in SKOV3 cells.

Antitumor Research on Artemisinin and Its Bioactive Derivatives

Cancer is the leading cause of human death which seriously threatens human life. The antimalarial drug artemisinin and its derivatives have been discovered with considerable anticancer properties. Simultaneously, a variety of target-selective artemisinin-related compounds with high efficiency have been discovered. Many researches indicated that artemisinin-related compounds have cytotoxic effects against a variety of cancer cells through pleiotropic effects, including inhibiting the proliferation of tumor cells, promoting apoptosis, inducing cell cycle arrest, disrupting cancer invasion and metastasis, preventing angiogenesis, mediating the tumor-related signaling pathways, and regulating tumor microenvironment. More importantly, artemisinins demonstrated minor side effects to normal cells and manifested the ability to overcome multidrug-resistance which is widely observed in cancer patients. Therefore, we concentrated on the new advances and development of artemisinin and its derivatives as potential antitumor agents in recent 5 years. It is our hope that this review could be helpful for further exploration of novel artemisinin-related antitumor agents.

Novel natural product therapeutics targeting both inflammation and cancer

Inflammation is recently recognized as one of the hallmarks of human cancer. Chronic inflammatory response plays a critical role in cancer development, progression, metastasis, and resistance to chemotherapy. Conversely, the oncogenic aberrations also generate an inflammatory microenvironment, enabling the development and progression of cancer. The molecular mechanisms of action that are responsible for inflammatory cancer and cancer-associated inflammation are not fully understood due to the complex crosstalk between oncogenic and pro-inflammatory genes. However, molecular mediators that regulate both inflammation and cancer, such as NF-κB and STAT have been considered as promising targets for preventing and treating these diseases. Recent works have further demonstrated an important role of oncogenes (e.g., NFAT1, MDM2) and tumor suppressor genes (e.g., p53) in cancer-related inflammation. Natural products that target these molecular mediators have shown anticancer and anti-inflammatory activities in preclinical and clinical studies. Sesquiterpenoids (STs), a class of novel plant-derived secondary metabolites have attracted great interest in recent years because of their diversity in chemical structures and pharmacological activities. At present, we and other investigators have found that dimeric sesquiterpenoids (DSTs) may exert enhanced activity and binding affinity to molecular targets due to the increased number of alkylating centers and improved conformational flexibility and lipophilicity. Here, we focus our discussion on the activities and mechanisms of action of STs and DSTs in treating inflammation and cancer as well as their structure-activity relationships.

Octreotide-modified liposomes containing daunorubicin and dihydroartemisinin for treatment of invasive breast cancer

Tumor invasion is considered a major promoter in the initiation of tumor metastasis, which is supposed to cause most cancer-related deaths. In the present study, octreotide (OCT)-modified daunorubicin plus dihydroartemisinin liposomes were developed and characterized. Evaluations were undertaken on breast cancer MDA-MB-435S cells and MDA-MB-435S xenografts nude mice. The liposomes were ∼100 nm in size with a narrow polydispersity index. In vitro results showed that the OCT-modified daunorubicin plus dihydroartemisinin liposomes could enhance cytotoxicity and cellular uptake by OCT-SSTRs (somatostatin receptors)-mediated active targeting, block on tumor cell wound healing and migration by incorporating dihydroartemisinin. The action mechanism might be related to regulations on E-cadherin, α5β1-integrin, TGF-β1, VEGF and MMP2/9 in breast cancer cells. In vivo, the liposomes displayed a prolonged circulating time, more accumulation in tumor location, and a robust overall antitumor efficacy with no obvious toxicity at the test dose in MDA-MB-435S xenograft mice. In conclusion, the OCT-modified daunorubicin plus dihydroartemisinin liposomes could prevent breast cancer invasion, hence providing a possible strategy for treatment of metastatic breast cancer.

EMT: Present and future in clinical oncology

Epithelial/mesenchymal transition (EMT) has emerged as a key regulator of metastasis by facilitating tumor cell invasion and dissemination to distant organs. Recent evidences support that the reverse mesenchymal/epithelial transition (MET) is required for metastatic outgrowth; moreover, the existence of hybrid epithelial/mesenchymal (E/M) phenotypes is increasingly being reported in different tumor contexts. The accumulated data strongly support that plasticity between epithelial and mesenchymal states underlies the dissemination and metastatic potential of carcinoma cells. However, the translation into the clinics of EMT and epithelial plasticity processes presents enormous challenges and still remains a controversial issue. In this review, we will evaluate current evidences for translational applicability of EMT and depict an overview of the most recent EMT in vivo models, EMT marker analyses in human samples as well as potential EMT therapeutic approaches and ongoing clinical trials. We foresee that standardized analyses of EMT markers in solid and liquid tumor biopsies in addition to innovative tools targeting the E/M states will become promising strategies for future translation to the clinical setting.