Dihydroartemisinin improves the efficiency of chemotherapeutics in lung carcinomas in vivo and inhibits murine Lewis lung carcinoma cell line growth in vitro

Exploring combinations of dihydroartemisinin for cancer therapy: A comprehensive review

Cancer remains a significant threat to human health due to its multifaceted causes and complex pathogenesis. While advancements in research have improved outcomes for many cancer patients, treatments for specific tumor types still face limitations. Dihydroartemisinin (DHA), an active metabolite of artemisinin and its derivatives, has proven to be an effective anti-malarial agent. Recently, its anticancer potential has garnered increasing interest as it acts through multiple molecular pathways, including anti-proliferation, induction of apoptosis, autophagy and endoplasmic reticulum (ER) stress, anti-metastasis, inhibition of angiogenesis, and modulation of immune function. This review aims to thoroughly explain and summarize the mechanisms of DHA against cancer and the latest progress in this field. Due to the insufficiency of monotherapy in effectively treating cancer, the use of chemotherapy in combination with alternative therapies has witnessed a notable increase in popularity. DHA has shown synergistic anti-tumor efficacy with a range of therapeutic drugs, but its co-delivery with chemotherapeutics has been limited by low solubility and bioavailability. Nanotechnology-assisted co-delivery of anti-tumor agents, utilizing advanced stimulus-triggered drug release systems in tumor cells, offers the potential to enhance selective delivery and increase antitumor efficacy. Additionally, this article provides suggestions for further research on the anticancer effects of DHA.

New Roles of Artemisinins in Atherosclerosis Progression

Artemisinin is a natural compound derived from the Chinese plant Artemisia annua , which was officially approved by the FDA for its antimalarial effects. In recent years, a growing body of studies has shown the novel function of artemisinin in atherosclerosis therapy. In vivo studies have shown that artemisinin can inhibit the progression of atherosclerosis plaque. In the present review, the evidence showing the inhibitory effects of artemisinin on the progression of atherosclerosis plaque and its underlying mechanisms is discussed. Mechanistically, artemisinin and its derivatives act by modulating various atherosclerosis-mediating risk factors, including hyperlipidemia, inflammation, oxidative stress, and malfunctioning vascular smooth muscle cells (VSMCs). Notably, artesunate, but not artemisinin, can attenuate the plasma levels of TG, TC, VLDL-C, and LDL-c, along with a substantial decline in arterial lipid deposition through enhancing the LDPL activity via inducing the KFL2/NRF2/TCF7L2 axis. Artemisinin was found to ameliorate the atherosclerosis plaque inflammation by reducing monocyte adhesion and subsequent transmigration to the intima, via inhibiting the expression of ICAM-1 and VCAM-1, diminishing NLRP3 inflammasome activation, and reducing the expression of inflammatory factors such as IL-1β, IL-18, TNF-α, MCP-1, and TGF-β1 mechanistically and mainly via suppressing the by NF-κB activity. Artemisinin could exert antioxidant effects through activating the PI3K/Akt/eNOS signaling pathway and suppressing the ROS-mediated NF-κB signal pathway. Artemisinin could also improve the VSMC function in the atherosclerosis plaque. These findings can suggest artemisinin as a new therapeutic agent for treating atherosclerosis; however, future clinical trials are warranted to validate its therapeutic efficiency in patients with atherosclerosis.

Proanthocyanidin Regulates NETosis and Inhibits the Growth and Proliferation of Liver Cancer Cells - In Vivo, In Vitro and In Silico Investigation

Liver cancer ranks third in global cancer-related mortality, with about 700,000 deaths recorded yearly, making it one of the most common cancers worldwide. Even though prognoses differ according to the severity of the diseases, many patients now exhibit an increased life cycle since the implementation of chemotherapy. In the current study, we investigated the effect of proanthocyanidin ‒a polyphenol molecule found in many plants‒ on the proliferation and invasion of liver cancer cells. In particular, we determined the effect of proanthocyanidin on the serum levels of four strategic liver cancer target, TNFα, IL-6, cfDNA, and IL-1β. Further molecular insight on the inhibitory mechanism of proanthocyanidin against TNFα, IL-6, and IL-1β was obtained via molecular docking, molecular dynamics simulations and binding free energy calculations. Results showed that proanthocyanidin inhibited the growth of HepG2 and HEP3B cells, and effectively reduced clonogenic survival and invasion potential when compared to control cells. Proanthocyanidin was also found to suppress the expression of Bcl-2 (26 kDa) protein in HepG2 cells, while increasing the expression of Bax (21 kDa). Molecular dynamics (MD) and thermodynamic binding free energy calculations showed that proanthocyanidin maintained stable binding within the active site of target proteins across the entire 100 ns MD simulation period, and its binding affinity outscored respective control molecules.In conclusion, the multifaceted analysis showcased in this study demonstrated promising anti-cancer effect of proanthocyanidin on HepG2 and HEP3B cancer cells, highlighting its potential as a viable liver cancer therapeutic alternative.

Dihydroartemisinin ameliorates skeletal muscle atrophy in the lung cancer cachexia mouse model

INTRODUCTION

Cancer cachexia (CC) is characterized by weight loss with specifically reduced skeletal muscles and adipose tissues in patients with late-stage cancer. Dihydroartemisinin (DHA), an effective antimalarial derivative of artemisinin, has been demonstrated to have anti-inflammatory and antitumor properties.

MATERIALS AND METHODS

This study examined the effects of DHA on the Lewis lung carcinoma (LLC)-induced CC mouse model.

RESULTS

DHA treatment significantly increases tumor-free body weight and food intake but decreases serum interleukin-6 level and tumor weight in CC mice. In addition, DHA treatment relieves muscle atrophy and decreases muscle ring finger 1 (MuRF1) and F-box-only protein 32 (Fbx32) expressions in CC mice. In vitro, DHA reverses the reduction in myotube formation induced by an LLC-conditioned medium and increases Fbx32 expression in C2C12 mouse myotubular cells.

CONCLUSIONS

Our study demonstrated that DHA ameliorates the cachectic state and skeletal muscle atrophy in LLC-induced cachectic mouse models, suggesting its therapeutic potential for CC.

Dihydroartemisinin suppresses glioma growth by repressing ERRα-mediated mitochondrial biogenesis

Malignant gliomas are an exceptionally lethal form of cancer with limited treatment options. Dihydroartemisinin (DHA), a sesquiterpene lactone antimalarial compound, has demonstrated therapeutic effects in various solid tumors. In our study, we aimed to investigate the mechanisms underlying the anticancer effects of DHA in gliomas. To explore the therapeutic and molecular mechanisms of DHA, we employed various assays, including cell viability, flow cytometry, mitochondrial membrane potential, glucose uptake and glioma xenograft models. Our data demonstrated that DHA significantly inhibited glioma cell proliferation in both temozolomide-resistant cells and glioma stem-like cells. We found that DHA-induced apoptosis occurred via the mitochondria-mediated pathway by initiating mitochondrial dysfunction before promoting apoptosis. Moreover, we discovered that DHA treatment substantially reduced the expression of the mitochondrial biogenesis-related gene, ERRα, in glioma cells. And the ERRα pathway is a critical target in treating glioma with DHA. Our results also demonstrated that the combination of DHA and temozolomide synergistically inhibited the proliferation of glioma cells. In vivo, DHA treatment remarkably extended survival time in mice bearing orthotopic glioblastoma xenografts. Thus, our findings suggest that DHA has a novel role in modulating cancer cell metabolism and suppressing glioma progression by activating the ERRα-regulated mitochondrial apoptosis pathway.

Inhibition of Liver Cancer Cell Viability by Triazole through Up-regulation of p38 Phosphorylation and Targeting the Activation of p-ERK1/2 and Akt Protein Expression

The present study was aimed to explore the effect of triazole on growth and viability of liver cancer cells. Cell growth was examined using the MTT test and expression of several proteins was assessed by western blotting assay. The Matrigel-coated Transwell assay was employed to examine the infiltration of cells. The data from MTT assay showed that MHCC97H and H4TG liver cancer cell viability was inhibited by triazole in a concentration-dependent manner. After treatment with 0.5, 1.0, 2.0, 4, 8, and 16 µM doses of triazole, the rate of H4TG cell viability was decreased to 96, 73, 58, 39, 29, and 28%, respectively. Treatment of MHCC97H cells with 0.5, 1.0, 2.0, 4, 8, and 16 µM doses of triazole resulted in a reduction in cell viability to 94, 70, 53, 35, 22, and 21%, respectively. Triazole treatment also led to a significant reduction in MHCC97H cell invasiveness compared to the control cells. In MHCC97H cells treated with triazole, there was a noticeable decrease in the levels of p-ERK1/2, and p-Akt protein expression. Treatment of MHCC97H cells with triazole resulted in a prominent increase in p-p38 level. In summary, triazole inhibits growth and viability of liver cancer cells through targeting the activation of p-ERK1/2 and Akt proteins. Therefore, triazole may be investigated further as a therapeutic agent for the treatment of liver cancer.

Dihydroartemisinin breaks the immunosuppressive tumor niche during cisplatin treatment in Hepatocellular carcinoma

OBJECTIVE

Hepatocellular carcinoma, characterized by high mortality rates, often exhibits limited responsiveness to conventional treatments such as surgery, radiotherapy, and chemotherapy. Therefore, identifying a sensitizer for cisplatin has become crucial. Dihydroartemisinin, known for its potent role of tumor treatment, arises as a prospective candidate for cisplatin sensitization in clinical settings.

METHODS

A mouse model of liver tumor was established through chemical induction of DEN/TCPOBOP. Upon successful model establishment, ultrasound was employed to detect tumors, Hematoxylin and eosin staining was conducted for observation of liver tissue pathology, and ELISA was utilized to assess cytokine changes (IFN-γ, IL-2, IL-4, IL-10, TGF-β, IL-1β, CCL2, and CCL21) in peripheral blood, para-tumor tissues, and tumor tissues. The infiltration of CD8+T cells and macrophages in tumor tissue sections was detected by immunofluorescence.

RESULTS

Dihydroartemisinin combined with cisplatin obviously restrained the growth of liver tumors in mice and improved the weight and spleen loss caused by cisplatin. Cisplatin treatment of liver tumor mice increased the content of CCL2 and the number of macrophages in tumor tissues and promoted the formation of an immunosuppressive microenvironment. The combination therapy decreased the content of TGF-β in tumor tissues while increasing CCL2 levels in para-tumor tissues. Both combination therapy and cisplatin alone increased the number of CD8+T cells in tumor tissue, but there was no difference between them.

CONCLUSION

Dihydroartemisinin combined with cisplatin obviously prevented the deterioration of liver tumor in hepatocellular carcinoma mice and improve the therapeutic effect of cisplatin by improving the immunosuppressive microenvironment induced by cisplatin. Our findings provide a theoretical basis for considering dihydroartemisinin as an adjuvant drug for cisplatin in the treatment of hepatocellular carcinoma in the future.

Protective effect of tretinoin on cervical cancer growth and proliferation through downregulation of pFAK2 expression

BACKGROUND

Cervical cancer, a life-threatening disease, is the seventh most commonly detected cancer among women throughout the world. The present study investigated the effect of tretinoin on cervical cancer growth and metastasis in vitro and in vivo in the mice model.

MATERIALS AND METHODS

Cell Counting Kit-8, clonogenic survival, and transwell chamber assays were used for determination cells proliferation, colony formation, and invasiveness. Western blotting assay was used for assessment of protein expression whereas AutoDock Vina and Discovery studio software for in silico studies.

RESULTS

Tretinoin treatment significantly (p < .05) reduced the proliferation of HT-3 and Caski cells in concentration-based manner. Incubation with tretinoin caused a significant decrease in clonogenic survival of HT-3 and Caski cells compared with the control cultures. The invasive potential of HT-3 cells was decreased to 18%, whereas that of Caski cells to 21% on treatment with 8 μM concentration of tretinoin. In HT-3 cells, tretinoin treatment led to a prominent reduction in p-focal adhesion kinase (FAK), matrix metalloproteinases (MMP)-2, and MMP-9 expression in HT-3 cells. Treatment of the cervical cancer mice model with tretinoin led to a prominent decrease in tumor growth. The metastasis of tumor in model cervical cancer mice group was effectively inhibited in spleen, intestines, and peritoneal cavity. In silico studies showed that tretinoin interacts with alanine, proline, isoleucine, and glycine amino acid residues of FAK protein to block its activation. The 2-dimensional diagram of interaction of tretinoin with FAK protein revealed that tretinoin binds to alanine and glycine amino acids through conventional hydrogen bonding.

CONCLUSION

In summary, tretinoin suppressed the proliferation, colony formation, and invasiveness of cervical cancer cells in vitro. It decreased the expression of activated focal adhesion kinase, MMP-2, and MMP-9 in HT-3 cells in dose-dependent manner. In silico studies showed that tretinoin interacts with alanine and glycine amino acids through conventional hydrogen bonding. In vivo data demonstrated that treatment of the cervical cancer mice model with tretinoin led to a prominent decrease in tumor growth. Therefore, tretinoin can be developed as an effective therapeutic agent for cervical cancer treatment.

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.

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.

Research progress of VEGFR small molecule inhibitors in ocular neovascular diseases

Angiogenesis is the biological process in which existing blood vessels generate new ones and it is essential for body growth and development, wound healing, and granulation tissue formation. Vascular endothelial growth factor receptor (VEGFR) is a crucial cell membrane receptor that binds to VEGF to regulate angiogenesis and maintenance. Dysregulation of VEGFR signaling can lead to several diseases, such as cancer and ocular neovascular disease, making it a crucial research area for disease treatment. Currently, anti-VEGF drugs commonly used in ophthalmology are mainly four macromolecular drugs, Bevacizumab, Ranibizumab, Conbercept and Aflibercept. Although these drugs are relatively effective in treating ocular neovascular diseases, their macromolecular properties, strong hydrophilicity, and poor blood-eye barrier penetration limit their efficacy. However, VEGFR small molecule inhibitors possess high cell permeability and selectivity, allowing them to traverse and bind to VEGF-A specifically. Consequently, they have a shorter duration of action on the target, and they offer significant therapeutic benefits to patients in the short term. Consequently, there is a need to develop small molecule inhibitors of VEGFR to target ocular neovascularization diseases. This review summarizes the recent developments in potential VEGFR small molecule inhibitors for the targeted treatment of ocular neovascularization diseases, with the aim of providing insights for future studies on VEGFR small molecule inhibitors.

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.

Aqueous Extract of Artemisia annua Shows In Vitro Antimicrobial Activity and an In Vivo Chemopreventive Effect in a Small-Cell Lung Cancer Model

Artemisia annua (A. annua) has been used as a medicinal plant in the treatment of several infectious and non-infectious diseases in the forms of tea and press juice since ancient times. The aim of this study was to evaluate the aqueous extract of A. annua (AAE) as an antimicrobial agent in vitro and to evaluate its chemopreventive efficacy in vivo in a small-cell lung cancer (SCLC) animal model. The dried powder of AAE was prepared using the Soxhlet extraction system from the leaves of Artemisia annua. The in vitro activity of AAE was determined against Candida albicans (C. albicans), Enterococcus faecalis (E. faecalis), Klebsiella pneumoniae (K. pneumoniae), and methicillin-resistant Staphylococcus aureus (MRSA) using the agar well diffusion method and propidium iodide (PI)-stained microbial death under a confocal microscope. The pretreatment of mice with AAE was initiated two weeks before the first dose of benzo[a]pyrene and continued for 21 weeks. The chemopreventive potential of the extract was evaluated by flow cytometry and biochemical and histopathological analyses of the tissues and serum accordingly, after sacrificing the mice. The data revealed the antimicrobial potential of AAE against all the species investigated, as it showed growth-inhibitory activity by MIC, as well as confocal microscopy. The pretreatment of AAE exhibited significant protection in carcinogen-modulated, average body weight (ABW), and relative organ weight (ROW) cancer biomarkers in the serum and antioxidants in the lungs. The hematoxylin and eosin (H&E) staining of the tissues revealed that AAE prevented malignancy in the lungs. AAE also induced apoptosis and decreased intracellular reactive oxygen species (ROS) in the lung cells analyzed by flow cytometry. The current findings demonstrated the use of AAE as an alternative medicine in the treatment of infectious disease and the chemoprevention of lung cancer. To our knowledge, this is the first study that summarizes the chemopreventive potential of AAE in a lung cancer model in vivo. However, further investigations are suggested to understand the role of AAE to potentiate the therapeutic index of the commercially available drugs that show multiple drug resistance against microbial growth and high toxicity during cancer chemotherapy.

Dihydroartemisinin enhances the anti-tumor activity of oxaliplatin in colorectal cancer cells by altering PRDX2-reactive oxygen species-mediated multiple signaling pathways

BACKGROUND

Globally, colorectal cancer (CRC) is one of the leading causes of cancer-related deaths. Oxaliplatin based treatments are frequently used as chemotherapeutic methods for CRC, however, associated side effects and drug resistance often limit their clinical application. Dihydroartemisinin (DHA) induces apoptosis in various cancer cells by increasing reactive oxygen species (ROS) production. However, the direct target of DHA and underlying molecular mechanisms in oxaliplatin-mediated anti-tumor activities against CRC are unclear.

METHODS

We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), flow cytometry, and colony formation assays to investigate cell phenotype alterations and ROS generation. We also used quantitative Real-Time PCR (qRT-PCR) and western blotting to measure relative gene and protein expression. Finally, an in vivo mouse xenograft model was used to assess the anti-tumor activity of oxaliplatin and DHA alone, and combinations.

RESULTS

DHA synergistically enhanced the anti-tumor activity of oxaliplatin in colon cancer cells by regulating ROS-mediated ER stress, signal transducer and activator of transcription 3 (STAT3), C-Jun-amino-terminal kinase (JNK), and p38 signaling pathways. Mechanistically, DHA increased ROS levels by inhibiting peroxiredoxin 2 (PRDX2) expression, and PRDX2 knockdown sensitized DHA-mediated cell growth inhibition and ROS production in CRC cells. A mouse xenograft model showed strong anti-tumor effects from combination treatments when compared with single agents.

CONCLUSIONS

We demonstrated an improved therapeutic strategy for CRC patients by combining DHA and oxaliplatin treatments.

An albumin-binding dimeric prodrug nanoparticle with long blood circulation and light-triggered drug release for chemo-photodynamic combination therapy against hypoxia-induced metastasis of lung cancer

Photodynamic therapy (PDT) has been widely used in cancer therapy, but its therapeutic effect is reduced by the aggravating hypoxic microenvironment via upregulating hypoxia-associated proteins and promoting tumor metastasis. To mitigate these issues, we designed an albumin-binding and light-triggered core-shell dimeric prodrug nanoparticle to inhibit hypoxia-induced tumor metastasis and enhance the PDT efficacy. The prodrug nanoparticles, Ce6&DHA-S-DHA@CMN NPs (CDC NPs), were prepared using a single thioether-linked dihydroartemisinin (DHA) dimer co-encapsulated with Chlorin e6 (Ce6) and stabilized by albumin-capturing maleimide- and hypoxia-sensitive 2-nitroimidazole-modified carboxymethyl chitosan (CMCTS-MAL&NI, CMN for short). Upon laser irradiation, Ce6 could generate reactive oxygen species (ROS), which not only exerted the effect of the PDT but also broke the ROS-sensitive single thioether bridge in the dimeric prodrug DHA-S-DHA, thus accelerating the disassembly of the nanoparticles. DHA-S-DHA served as both an ROS-responsive carrier for Ce6 and a chemotherapeutic drug, synergizing with PDT and inhibiting tumor metastasis by downregulating hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF). Polyethylene glycol (PEG) modification has been widely used to stabilize hydrophobic prodrug nanoparticles and prolong the circulation time, but the PEGylated nanoparticles always suffer from accelerated blood clearance (ABC), a phenomenon which restricts their application severely. In this study, PEG was replaced by an amphipathic micelle, CMN, which could specifically capture albumin in the blood, conferring the nanoparticles long circulation and no ABC phenomenon. Under the aggravating hypoxic condition during PDT, the conversion of 2-nitroimidazole groups to 2-aminoimidazole groups in CMN could destabilize the structure of the shell and accelerate drug release. Results showed that the novel CDC NPs exhibited unique advantages in chemo-photodynamic combination therapy, such as long systemic circulation, high tumor accumulation, light-triggered drug release, HIF-1α/VEGF downregulation, and anti-metastasis efficacy, which provided a new route to overcome the ABC phenomenon of the PEGylated prodrug nanoparticles and reverse the hypoxia-induced metastasis simultaneously.

Synthesis and biological evaluation of novel artemisone-piperazine-tetronamide hybrids

For the first time, six novel artemisone-piperazine-tetronamide hybrids (12a-f) were efficiently synthesised from dihydroartemisinin (DHA) and investigated for their in vitro cytotoxicity against some human cancer cells and benign cells. All the targets showed good cytotoxic activity in vitro. Hybrid 12a exhibited much better inhibitory activity against human liver cancer cell line SMMC-7721 (IC₅₀ = 0.03 ± 0.04 μM for 24 h) than the parent DHA (IC₅₀ > 0.7 μM), and two references, vincristine (VCR; IC₅₀ = 0.27 ± 0.03 μM) & cytosine arabinoside (ARA; IC₅₀ = 0.63 ± 0.04 μM). Furthermore, hybrid 12a had low toxicity against human benign liver cell line LO2 (IC₅₀ = 0.70 ± 0.02 μM for 24 h) compared with VCR, ARA, and DHA in vitro. Moreover, the inhibitory activity of hybrid 12a was obviously enhanced when human liver cancer cell line MHCC97H absorbed Fe²⁺ in vitro.

Synthesis of artemisinin-piperazine-furan ether hybrids and evaluation of in vitro cytotoxic activity

For the first time, eight novel artemisinin-piperazine-furane ether hybrids (5a-h) were efficiently synthesized and investigated for their in vitro cytotoxic activity against some human cancer and benign cells. The absolute configuration of hybrid 5c was determined by X-ray crystallographic analysis. Hybrids 5a-h exhibited more pronounced growth-inhibiting action on hepatocarcinoma cell lines than their parent dihydroartemisinin (DHA) and the reference cytosine arabinoside (ARA). The hybrid 5a showed the best cytotoxic activity against human hepatocarcinoma cells SMMC-7721 (IC₅₀ = 0.26 ± 0.03 μM) after 24 h. Furthermore, hybrid 5a also showed good cytotoxic activity against human breast cancer cells MCF-7 and low cytotoxicity against human breast benign cells MCF-10A in vitro. We found the cytotoxicity of hybrid 5a did not change when tumour cells absorb iron sulfate (FeSO₄); thus, we conclude the anti-tumour mechanism induced by iron ions (Fe²⁺) is unclear.

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.

Eliminating Radiation Resistance of Non-Small Cell Lung Cancer by Dihydroartemisinin Through Abrogating Immunity Escaping and Promoting Radiation Sensitivity by Inhibiting PD-L1 Expression

Radiation resistance is linked to immune escaping and radiation sensitivity. In this study, we found that the PD-L1 expressions of non-killed tumor cells in NSCLC were enhanced after radiotherapy, and dihydroartemisinin (DHA) could synergistically enhance the antitumor effect of radiotherapy in NSCLC. A total of 48 NSCLC patients with sufficient tumor tissues for further analyses were enrolled. The PD-L1 expressions of NSCLC were evaluated by immunohistochemistry. Cell apoptosis was measured by flow cytometry, and the relationship between the PD-L1 expression and radiation resistance was investigated in patient specimens, xenograft model, and cell lines. First, the results indicate that the PD-L1 expression of NSCLC was positively related with the radiation resistance. Second, we found that DHA could eliminate the radiation resistance and synergistically enhance the antitumor effect of radiotherapy in the NSCLC cells lines and xenograft model. Finally, mechanistically, DHA could inhibit the PD-L1 expression to avoid immune escaping by inhibiting TGF-β, PI3K/Akt, and STAT3 signaling pathways. In addition, DHA could activate TRIM21 and regulate the EMT-related proteins by inhibiting the PD-L1 so as to enhance the radiation sensitivity and eliminate radiation resistance to NSCLC. Collectively, this study established a basis for the rational design of integrated radiotherapy and DHA for the treatment of NSCLC.

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.

Nanoparticles Formulations of Artemisinin and Derivatives as Potential Therapeutics for the Treatment of Cancer, Leishmaniasis and Malaria

Cancer, malaria, and leishmaniasis remain the deadly diseases around the world although several strategies of treatment have been developed. However, most of the drugs used to treat the aforementioned diseases suffer from several pharmacological limitations such as poor pharmacokinetics, toxicity, drug resistance, poor bioavailability and water solubility. Artemisinin and its derivatives are antimalarial drugs. However, they also exhibit anticancer and antileishmanial activity. They have been evaluated as potential anticancer and antileishmanial drugs but their use is also limited by their poor water solubility and poor bioavailability. To overcome the aforementioned limitations associated with artemisinin and its derivatives used for the treatment of these diseases, they have been incorporated into nanoparticles. Several researchers incorporated this class of drugs into nanoparticles resulting in enhanced therapeutic outcomes. Their potential efficacy for the treatment of parasitic infections such as malaria and leishmaniasis and chronic diseases such as cancer has been reported. This review article will be focused on the nanoparticles formulations of artemisinin and derivatives for the treatment of cancer, malaria, and leishmaniasis and the biological outcomes (in vitro and in vivo).

Dihydroartemisinin Induces Growth Arrest and Overcomes Dexamethasone Resistance in Multiple Myeloma

The discovery of artemisinin (ART) for malaria treatment won the 2015 Nobel Prize in Medicine, which inspired the rediscovery and development of ART for the treatment of other diseases including cancer. In this study, we investigated the potential therapeutic effect of ART and dihydroartemisinin (DHA) on multiple myeloma (MM) cells including primary MM cells and in 5TMM3VT mouse model. Both in vitro and in vivo experiments showed that DHA might be a more promising anti-MM agent with significantly improved efficacy compared to ART. Mechanistic analyses suggested that DHA activated the mitochondrial apoptotic pathway by interacting with ferrous (Fe2+) ions and oxygen to produce reactive oxygen species (ROS). Intriguingly, DHA could reverse the upregulated expression of B-cell lymphoma 2 (Bcl-2) protein, a typical mitochondrial apoptotic marker, induced by dexamethasone (Dexa) in MM. We further demonstrated that DHA treatment could overcome Dexa resistance and enhance Dexa efficacy in MM. Additionally, DHA combined with Dexa resulted in increased ROS production and cytochrome C translocation from the mitochondria to the cytoplasm, resulting in alterations to the mitochondrial membrane potential and caspase-mediated apoptosis. In summary, our study demonstrated that DHA was superior to ART in MM treatment and overcame Dexa resistance both in vitro and in vivo, providing a promising therapeutic strategy for MM therapy.

Anti-malarial drug, artemisinin and its derivatives for the treatment of respiratory diseases

Artemisinins are sesquiterpene lactones with a peroxide moiety that are isolated from the herb Artemisia annua. It has been used for centuries for the treatment of fever and chills, and has been recently approved for the treatment of malaria due to its endoperoxidase properties. Progressively, research has found that artemisinins displayed multiple pharmacological actions against inflammation, viral infections, and cell and tumour proliferation, making it effective against diseases. Moreover, it has displayed a relatively safe toxicity profile. The use of artemisinins against different respiratory diseases has been investigated in lung cancer models and inflammatory-driven respiratory disorders. These studies revealed the ability of artemisinins in attenuating proliferation, inflammation, invasion, and metastasis, and in inducing apoptosis. Artemisinins can regulate the expression of pro-inflammatory cytokines, nuclear factor-kappa B (NF-κB), matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), promote cell cycle arrest, drive reactive oxygen species (ROS) production and induce Bak or Bax-dependent or independent apoptosis. In this review, we aim to provide a comprehensive update of the current knowledge of the effects of artemisinins in relation to respiratory diseases to identify gaps that need to be filled in the course of repurposing artemisinins for the treatment of respiratory diseases. In addition, we postulate whether artemisinins can also be repurposed for the treatment of COVID-19 given its anti-viral and anti-inflammatory properties.

Fabrication and in vivo evaluation of ligand appended paclitaxel and artemether loaded lipid nanoparticulate systems for the treatment of NSCLC: A nanoparticle assisted combination oncotherapy

The aim of present study was to develop folate appended PEGylated solid lipid nanoparticles(SLNs) of paclitaxel(FPS) and artemether(FAS). The SLNs were prepared by employing high pressure homogenization technique. The results of MTT assays revealed better cytotoxicity of FPS when given in combination with FAS on human lung cancer cell line H-1299 as compared to pure drugs, unconjugated SLNs and FPS alone. The cellular uptake of FPS and FAS was confirmed by fluorescence imaging and flow cytometric analysis. In-vivo pharmacokinetic study revealed better absorption and long circulation of FPS and FAS, which further leads to increased relative bioavailability of drugs(13.81-folds and 7.07-folds for PTX and ART, respectively) as compared to their solutions counterpart. In-vivo pharmacodynamic study confirmed tumor regression of developed SLNs formulations, which was observed highest when used in combination of FPS and FAS. Serum creatinine, blood urea nitrogen(BUN), SGOT, albumin and total protein levels revealed that formulated FPS and FAS does not exhibit any renal and hepatic toxicity. It can be concluded that by administering ART-SLNs along with PTX-SLNs via oral route, anticancer potential of PTX was improved without any toxicity (both renal, hepatic), thus, indicating the potential of developed formulations in reducing dose related toxicity of PTX.

TMT-based proteomics analysis of the anti-hepatocellular carcinoma effect of combined dihydroartemisinin and sorafenib

Hepatocellular carcinoma (HCC), as the major primary liver cancer, is one of the most prevalent malignant diseases with a high mortality rate worldwide. Prior studies have demonstrated that dihydroartemisinin (DHA), the semisynthetic derivative of artemisinin, possesses anti-HCC activity. The multikinase inhibitor sorafenib has been approved for the treatment of HCC. However, the anti-HCC efficacy of DHA combined with sorafenib has not been reported. In this study, we confirmed the significantly enhanced anti-HCC efficacy of DHA in combination with sorafenib compared with that of each agent alone. Tandem Mass Tag (TMT) peptide labeling coupled with LC-MS/MS was used to quantify the proteins from the control, DHA, sorafenib, and DHA + sorafenib groups. In total, 532, 426, 628 differentially expressed proteins (fold change >1.20 or <0.83 and P-value <0.05) were determined by comparing DHA versus control, sorafenib versus control and DHA + sorafenib versus control groups, respectively. Moreover, optimized screening was performed, and 101 optimized differentially expressed proteins were identified. The results of functional analysis of the optimized differentially expressed proteins suggested that they were enriched in cell components such as membrane-bound vesicles, extracellular vesicles, and organelle lumens, and they were mainly involved in biological processes such as cellular component organization, response to stress, and response to chemicals; in addition, they were related to various molecular functions such as protein binding, chromatin binding and enzyme binding. KEGG pathway analysis showed that the optimized differentially expressed proteins were enriched in pyrimidine metabolism, RNA polymerase, base excision repair, and osteoclast differentiation. Protein-protein interaction (PPI) networks of some of the optimized upregulated proteins suggested that they might not only affect vitamin and fat digestion and absorption but may also be involved in tight junctions. In the PPI network, some of the optimized downregulated proteins were enriched in base excision repair, RNA polymerase, purine metabolism, pyrimidine metabolism and mucin type O-glycan biosynthesis. Overall, this research explored the anti-HCC efficacy of DHA combined with sorafenib by using the TMT-based quantitative proteomics technique and might facilitate the understanding of the related anti-HCC molecular mechanism.

Pleuromutilin Inhibits Proliferation and Migration of A2780 and Caov-3 Ovarian Carcinoma Cells and Growth of Mouse A2780 Tumor Xenografts by Down-Regulation of pFAK2

BACKGROUND Pleuromutilin is a natural tricyclic, derived from the fungus, Pleurotus mutilus. This study aimed to investigate the effects of pleuromutilin on migration and proliferation of A2780 and Caov-3 human ovarian carcinoma cells and the growth of A2780 tumor xenografts in mice and the molecular mechanisms involved. MATERIAL AND METHODS A2780 and Caov-3 human ovarian carcinoma cells were cultured with and without 40, 160, and 200 μM of pleuromutilin. The Edu fluorescence assay, the wound-healing assay, and Matrigel were used to measure A2780 and Caov-3 cell proliferation, migration, invasion, and adhesion in vitro, respectively. Western blot measured protein levels of FAK, p-FAK, MMP-2, and MMP-9. A2780 cells were injected subcutaneously into mice to determine the effects of pleuromutilin on the growth of tumor xenografts. RESULTS Pleuromutilin significantly reduced A2780 and Caov-3 cell proliferation at 48 h in a dose-dependent manner (P<0.05), and at 200 μM, pleuromutilin reduced cell proliferation by 21.43% and 23.65%, respectively. Treatment of A2780 cells with pleuromutilin significantly reduced cell migration, invasion, and adhesion and the expression of p-FAK, MMP-2, and MMP-9 compared with untreated controls. In the mouse tumor xenograft model, treatment with pleuromutilin significantly reduced tumor size compared with the untreated group and inhibited tumor metastasis to the intestine, spleen, and peritoneal cavity. CONCLUSIONS In A2780 and Caov-3 human ovarian carcinoma cells, pleuromutilin inhibited cell proliferation, migration, invasion, and adhesion in a dose-dependent manner, and reduced tumor growth and metastases in a mouse A2780 cell tumor xenograft model.

Indomethacin and juglone inhibit inflammatory molecules to induce apoptosis in colon cancer cells

Colorectal cancer (CRC) is the third most common fatal cancer. Indomethacin, a nonsteroidal anti-inflammatory drug, is known to reduce the occurrence of CRC. This study evaluated the potential anticolon cancer effects of juglone (5-hydroxy-1,4-naphthoquinone) in combination with indomethacin. Human colon adenocarcinoma cells (HT29) were subjected to treatment with indomethacin, juglone, and a combination of both. Morphological analysis, cell cycle regulation, and dual staining using acridine orange and ethidium bromide in control and treated cells revealed the apoptotic potential of these compounds. Bcl2 and inflammatory molecules (tumor necrosis factor-α, nuclear factor kappa B, and Cox-2) were found to be decreased with a concomitant increase in the expression of proapoptotic molecules (Bad, Bax, cytochrome c, and PUMA) as a result of the molecular regulation of Wnt, Notch, and peroxisome proliferator-activated receptor-γ signaling. Treatment with juglone was not as effective as with indomethacin; however, a combination of both was shown to be more effective, suggesting that juglone may be considered for therapeutic intervention of colon 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.

Dihydroartemisinin induces apoptosis and autophagy-dependent cell death in cholangiocarcinoma through a DAPK1-BECLIN1 pathway

Cholangiocarcinoma (CCA) is a very aggressive cancer arising from the malignant transformation of cholangiocytes. Intrahepatic CCA is associated with reactive inflammation and intense fibrosis of the hepatobiliary tract. Dihydroartemisinin (DHA), the active compound found in Artemisia annua, has been shown to possess anti-tumor activity in a variety of human cancers, including hepatoma. Here, we tested the ability of DHA to specifically kill CCA cells and have investigated the underlying mechanisms. DHA induced both apoptosis and autophagy-dependent caspase-independent cell death in many CCA cell lines, while being slightly toxic to immortalized cholangiocytes. DHA induced the expression of many apoptosis- and autophagy-related genes in CCA cells. In particular, it greatly induced the expression of DAPK1, and reduced the interaction of BECLIN1 with BCL-2 while promoting its interaction with PI3KC3. Genetic silencing of DAPK1 prevented DHA-induced autophagy. Pharmacologic and genetic inhibition of BECLIN1 function prevented autophagy and cell death induced by DHA in CCA cells. These data unravel a novel pathway of DHA cancer toxicity and open the possibility to introduce DHA in the therapeutic regimen for the treatment of CCA.

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.

Artemisinin and Its Synthetic Derivatives as a Possible Therapy for Cancer

To assess the possibility of using the antimalarial drug artemisinin and its synthetic derivatives as antineoplastic drugs. A Pubmed and Google Scholar (1983–2018) search was performed using the terms artemisinin, cancer, artesunate and Artemisia annua. Case reports and original research articles, review articles, and clinical trials in both humans and animals were evaluated. Both in vitro and in vivo clinical trials and case reports have shown promising activity of the artemisinin drug derivatives in treating certain types of cancer. However, the reported articles are few, and therefore not statistically significant. The minimal toxicity shown in clinical trials and case reports, along with the selective cytotoxic activity of the compounds, make them possible cancer therapies due to the emerging evidence of the drug’s effectiveness.

Artesunate enhances the therapeutic response of glioma cells to temozolomide by inhibition of homologous recombination and senescence

Glioblastoma multiforme (GBM), a malignant brain tumor with a dismal prognosis, shows a high level of chemo- and radioresistance and, therefore, attempts to sensitize glioma cells are highly desired. Here, we addressed the question of whether artesunate (ART), a drug currently used in the treatment of malaria, enhances the killing response of glioblastoma cells to temozolomide (TMZ), which is the first-line therapeutic for GBM. We measured apoptosis, necrosis, autophagy and senescence, and the extent of DNA damage in glioblastoma cells. Further, we determined the tumor growth in nude mice. We show that ART enhances the killing effect of TMZ in glioblastoma cell lines and in glioblastoma stem-like cells. The DNA double-strand break level induced by TMZ was not clearly enhanced in the combined treatment regime. Also, we did not observe an attenuation of TMZ-induced autophagy, which is considered a survival mechanism. However, we observed a significant effect of ART on homologous recombination (HR) with downregulation of RAD51 protein expression and HR activity. Further, we found that ART is able to inhibit senescence induced by TMZ. Since HR and senescence are pro-survival mechanisms, its inhibition by ART appears to be a key node in enhancing the TMZ-induced killing response. Enhancement of the antitumor effect of TMZ by co-administration of ART was also observed in a mouse tumor model. In conclusion, the amelioration of TMZ-induced cell death upon ART co-treatment provides a rational basis for a combination regime of TMZ and ART in glioblastoma therapy.

Dihydroartemisinin and gefitinib synergistically inhibit NSCLC cell growth and promote apoptosis via the Akt/mTOR/STAT3 pathway

Non‑small cell lung cancer (NSCLC) is among the leading causes of cancer‑associated mortality worldwide. In clinical practice, therapeutic strategies based on drug combinations are often used for the treatment of various types of cancer. The present study aimed to investigate the effects of the combination of dihydroartemisinin (DHA) and gefitinib on NSCLC. Cell Counting kit 8 assay was used to evaluate cell viability. Transwell assays were performed to investigate cellular migration and invasion, and cellular apoptosis was evaluated using the terminal deoxynucleotidyl transferase dUTP nick‑end labeling assay. Flow cytometry was used to investigate cell cycle distribution and the expression levels of target proteins were determined using western blot analysis. The results of the present study demonstrated that DHA (5, 10, 20, 50 and 100 µM) reduced cancer cell viability in a dose‑dependent manner in the NCI‑H1975 human NSCLC cell line and significantly enhanced gefitinib‑induced apoptosis. Furthermore, DHA and gefitinib co‑administration induced cell cycle arrest in G2/M phase, which was associated with a marked decline in the protein expression levels of G2/M regulatory proteins, including cyclin B1 and cyclin‑dependent kinase 1. The addition of DHA appeared to potentiate the inhibitory actions of gefitinib on the migratory and invasive capabilities of NCI‑H1975 cells. DHA and gefitinib co‑administration also downregulated the expression levels of phosphorylated (p)‑Akt, p‑mechanistic target of rapamycin, p‑signal transducer and activator of transcription 3 and B‑cell lymphoma 2 (Bcl‑2), and upregulated the expression of Bcl‑2‑associated X protein. In conclusion, the present results suggested that the combination of DHA and gefitinib may have potential as a novel and more effective therapeutic strategy for the treatment of patients with NSCLC.

Combination of onconase and dihydroartemisinin synergistically suppresses growth and angiogenesis of non-small-cell lung carcinoma and malignant mesothelioma

Onconase (Onc) is a cytotoxic ribonuclease derived from leopard frog oocytes or early embryos, and has been applied to the treatment of malignant mesothelioma in clinics. Onc also exhibits effective growth suppression of human non-small-cell lung cancer (NSCLC). Artemisinin (Art) and its derivatives are novel antimalarial drugs that exhibit antitumor and antivirus activities. In this study, we investigated the antitumor effects of combinations of Onc and an Art derivative, dihydroartemisinin (DHA), both in vitro and in vivo Isobologram analyses showed synergistic effects on the proliferation of NSCLC cells under the treatment with Onc and DHA. In vivo experiments also showed that the antitumor effect of Onc was markedly enhanced by DHA in mouse xenograft models. No obvious adverse effect was observed after the treatment. The density of microvasculature in the tumor tissues treated with Onc/DHA combination was lower than those treated with Onc or DHA alone. The above results are consistent with the results of the matrigel plug test for angiogenesis suppression using the Onc/DHA combination. These results imply that the anti-angiogenesis effects may make important contributions to the in vivo antitumor effects of the Onc/DHA combination treatment. The Onc/DHA combination therapy may have the potential to become a novel regimen for NSCLC and mesothelioma.

Methylene Homologues of Artemisone: An Unexpected Structure-Activity Relationship and a Possible Implication for the Design of C10-Substituted Artemisinins

We sought to establish if methylene homologues of artemisone are biologically more active and more stable than artemisone. The analogy is drawn with the conversion of natural O- and N-glycosides into more stable C-glycosides that may possess enhanced biological activities and stabilities. Dihydroartemisinin was converted into 10β-cyano-10-deoxyartemisinin that was hydrolyzed to the α-primary amide. Reduction of the β-cyanide and the α-amide provided the respective methylamine epimers that upon treatment with divinyl sulfone gave the β- and α-methylene homologues, respectively, of artemisone. Surprisingly, the compounds were less active in vitro than artemisone against P. falciparum and displayed no appreciable activity against A549, HCT116, and MCF7 tumor cell lines. This loss in activity may be rationalized in terms of one model for the mechanism of action of artemisinins, namely the cofactor model, wherein the presence of a leaving group at C10 assists in driving hydride transfer from reduced flavin cofactors to the peroxide during perturbation of intracellular redox homeostasis by artemisinins. It is noted that the carba analogue of artemether is less active in vitro than the O-glycoside parent toward P. falciparum, although extrapolation of such activity differences to other artemisinins at this stage is not possible. However, literature data coupled with the leaving group rationale suggest that artemisinins bearing an amino group attached directly to C10 are optimal compounds.

Cyclic AMP efflux inhibitors as potential therapeutic agents for leukemia

Apoptotic evasion is a hallmark of cancer. We propose that some cancers may evade cell death by regulating 3'-5'-cyclic adenosine monophosphate (cAMP), which is associated with pro-apoptotic signaling. We hypothesize that leukemic cells possess mechanisms that efflux cAMP from the cytoplasm, thus protecting them from apoptosis. Accordingly, cAMP efflux inhibition should result in: cAMP accumulation, activation of cAMP-dependent downstream signaling, viability loss, and apoptosis. We developed a novel assay to assess cAMP efflux and performed screens to identify inhibitors. In an acute myeloid leukemia (AML) model, several identified compounds reduced cAMP efflux, appropriately modulated pathways that are responsive to cAMP elevation (cAMP-responsive element-binding protein phosphorylation, and deactivation of Very Late Antigen-4 integrin), and induced mitochondrial depolarization and caspase activation. Blocking adenylyl cyclase activity was sufficient to reduce effects of the most potent compounds. These compounds also decreased cAMP efflux and viability of B-lineage acute lymphoblastic leukemia (B-ALL) cell lines and primary patient samples, but not of normal primary peripheral blood mononuclear cells. Our data suggest that cAMP efflux is a functional feature that could be therapeutically targeted in leukemia. Furthermore, because some of the identified drugs are currently used for treating other illnesses, this work creates an opportunity for repurposing.

Dihydroartemisinin targets VEGFR2 via the NF-κB pathway in endothelial cells to inhibit angiogenesis

The anti-malarial agent dihydroartemisinin (DHA) has strong anti-angiogenic activity. This study aimed to investigate the molecular mechanism underlying this effect of DHA on angiogenesis. We found that DHA shows a dose-dependent inhibition of proliferation and migration of in HUVECs. DHA specifically down-regulates the mRNA and protein expression of VEGFR2 in endothelial cells. Treatment with DHA increases IκB-α protein and blocks nuclear translocation of NF-κB p65. In addition, DHA directly regulates VEGFR2 promoter activity through p65 binding motif, and decreases the binding activity of p65 and VEGFR2 promoter, suggesting defective NF-κB signaling may underlie the observed effects of DHA on VEGFR2 expression. In the presence of the NF-κB inhibitor PDTC, DHA could not further repress VEGFR2. Co-treatment with PDTC and DHA produced minimal changes compared to the effects of either drug alone in in vitro angiogenesis assays. Similar findings were found in vivo through a mouse retinal neovascularization model examining the effects of PDTC and DHA. Our data suggested that DHA inhibits angiogenesis largely through repression of the NF-κB pathway. DHA is well tolerated, and therefore may be an ideal candidate to use clinically as an angiogenesis inhibitor for cancer treatment.

Anticancer Effect of AntiMalarial Artemisinin Compounds

The anti-malarial drug artemisinin has shown anticancer activity in vitro and animal experiments, but experience in human cancer is scarce. However, the ability of artemisinins to kill cancer cells through a variety of molecular mechanisms has been explored. A PubMed search of about 127 papers on anti-cancer effects of antimalarials has revealed that this class of drug, including other antimalarials, have several biological characteristics that include anticancer properties. Experimental evidences suggest that artemisinin compounds may be a therapeutic alternative in highly aggressive cancers with rapid dissemination, without developing drug resistance. They also exhibit synergism with other anticancer drugs with no increased toxicity toward normal cells. It has been found that semisynthetic artemisinin derivatives have much higher antitumor activity than their monomeric counterparts via mechanisms like apoptosis, arrest of cell cycle at G₀/G₁, and oxidative stress. The exact mechanism of activation and molecular basis of these anticancer effects are not fully elucidated. Artemisinins seem to regulate key factors such as nuclear factor-kappa B, survivin, NOXA, hypoxia-inducible factor-1α, and BMI-1, involving multiple pathways that may affect drug response, drug interactions, drug resistance, and associated parameters upon normal cells. Newer synthetic artemisinins have been developed showing substantial antineoplastic activity, but there is still limited information regarding the mode of action of these synthetic compounds. In view of the emerging data, specific interactions with established chemotherapy need to be further investigated in different cancer cells and their phenotypes and validated further using different semisynthetic and synthetic artemisinin derivatives.

Dihydroartemisinin inhibits glucose uptake and cooperates with glycolysis inhibitor to induce apoptosis in non-small cell lung carcinoma cells

Despite recent advances in the therapy of non-small cell lung cancer (NSCLC), the chemotherapy efficacy against NSCLC is still unsatisfactory. Previous studies show the herbal antimalarial drug dihydroartemisinin (DHA) displays cytotoxic to multiple human tumors. Here, we showed that DHA decreased cell viability and colony formation, induced apoptosis in A549 and PC-9 cells. Additionally, we first revealed DHA inhibited glucose uptake in NSCLC cells. Moreover, glycolytic metabolism was attenuated by DHA, including inhibition of ATP and lactate production. Consequently, we demonstrated that the phosphorylated forms of both S6 ribosomal protein and mechanistic target of rapamycin (mTOR), and GLUT1 levels were abrogated by DHA treatment in NSCLC cells. Furthermore, the upregulation of mTOR activation by high expressed Rheb increased the level of glycolytic metabolism and cell viability inhibited by DHA. These results suggested that DHA-suppressed glycolytic metabolism might be associated with mTOR activation and GLUT1 expression. Besides, we showed GLUT1 overexpression significantly attenuated DHA-triggered NSCLC cells apoptosis. Notably, DHA synergized with 2-Deoxy-D-glucose (2DG, a glycolysis inhibitor) to reduce cell viability and increase cell apoptosis in A549 and PC-9 cells. However, the combination of the two compounds displayed minimal toxicity to WI-38 cells, a normal lung fibroblast cell line. More importantly, 2DG synergistically potentiated DHA-induced activation of caspase-9, -8 and -3, as well as the levels of both cytochrome c and AIF of cytoplasm. However, 2DG failed to increase the reactive oxygen species (ROS) levels elicited by DHA. Overall, the data shown above indicated DHA plus 2DG induced apoptosis was involved in both extrinsic and intrinsic apoptosis pathways in NSCLC cells.

VSIG4 expression on macrophages facilitates lung cancer development

Tumor-associated macrophages are a prominent component of lung cancer stroma and contribute to tumor progression. The protein V-set and Ig domain-containing 4 (VSIG4), a novel B7 family-related macrophage protein that has the capacity to inhibit T-cell activation, has a potential role in the development of lung cancer. In this study, 10 human non-small-cell lung cancer specimens were collected and immunohistochemically analyzed for VSIG4 expression. Results showed massive VSIG4(+) cell infiltration throughout the samples. Immunofluorescent double staining showed that VSIG4 was present on CD68(+) macrophages, but absent from CD3(+) T cells, CD31(+) endothelial cells, and CK-18(+) epithelial cells. Moreover, VSIG4 was coexpressed on B7-H1(+) and B7-H3(+) cells in these tumor specimens. Transfection of the VSIG4 gene into 293FT cells demonstrated that the VSIG4 signal could inhibit cocultured CD4(+) and CD8(+) T-cell proliferation and cytokine (IL-2 and IFN-γ) production in vitro. Interestingly, in a murine tumor model induced by Lewis lung carcinoma cell line, we found that tumors grown in VSIG4-deficient (VSIG4(-/-)) mice were significantly smaller than those found in wild-type littermates. All of these results demonstrate that macrophage-associated VSIG4 is an activator that facilitates lung carcinoma development. Specific targeting of VSIG4 may prove to be a novel, efficacious strategy for the treatment of this carcinoma.

DJ-1 mediates the resistance of cancer cells to dihydroartemisinin through reactive oxygen species removal

Dihydroartemisinin (DHA), one of the main metabolites of artemisinin and its derivatives, presents anti-cancer potential in vitro and in vivo. To explore the mechanisms of resistance toward DHA, a DHA-resistant cell line, HeLa/DHA, was established with a resistance factor of 7.26 in vitro. Upon DHA treatment, apoptotic cells were significantly elicited in parental HeLa cells but minimally induced in HeLa/DHA cells. HeLa/DHA cells also displayed much less sensitivity to DHA-induced tumor suppression in cancer xenograft models than HeLa cells. Intriguingly, DHA-resistant cells did not display a multidrug-resistant phenotype. Based on a proteomic study employing LC-ESI-MS/MS together with pathway analysis, DJ-1 (PARK7) was found to be highly expressed in HeLa/DHA cells. Western blot and immunofluorescence assays confirmed the higher expression of DJ-1 in HeLa/DHA cells than in parental cells in both cell line and xenograft models. DJ-1 is translocated to the mitochondria of HeLa/DHA cells and oxidized, providing DJ-1 with stronger cytoprotection activity. Further study revealed that DJ-1 knockdown in HeLa/DHA cells abolished the observed resistance, whereas overexpression of DJ-1 endowed the parental HeLa cells with resistance toward DHA. Reactive oxygen species (ROS) were also significantly induced by either DHA or hydrogen peroxide in HeLa cells but not in resistant HeLa/DHA cells. When the cells were pretreated with N-acetyl-l-cysteine, the effect of DJ-1 knockdown on sensitizing HeLa/DHA cells to DHA was significantly attenuated. In summary, our study suggests that overexpression and mitochondrial translocation of DJ-1 provides HeLa/DHA cells with resistance to DHA-induced ROS and apoptosis.

Treatment of Iron-Loaded Veterinary Sarcoma by Artemisia annua

Artemisinin, a constituent of Artemisia annua L., is a well-known antimalarial drug. Artemisinin-type drugs also inhibit cancer growth in vitro and in vivo. Herbal extracts of A. annua inhibit the growth of cancer cell lines. Here, we report on the use of capsules containing powder of Herba Artemisiae annuae to treat pet sarcoma. The surgical tumor removal as standard treatment was supplemented by adjuvant therapy with A. annua. One cat and one dog with fibrosarcoma survived 40 and 37 months, respectively, without tumor relapse. Two other dogs suffering from fibrosarcoma and hemangioendothelial sarcoma also showed complete remission and are still alive after 39 and 26 months, respectively. A. annua was well tolerated without noticeable side effects. These four cases indicate that A. annua may be a promising herbal drug for cancer therapy.