A redox-responsive dihydroartemisinin dimeric nanoprodrug for enhanced antitumor activity

Redox-responsive drug delivery system emerges as a hopeful platform for tumor treatment. Dihydroartemisinin (DHA) has been investigated as an innovative tumor therapeutic agent. Herein, a DHA dimeric prodrug bridged with disulfide bond as linker (DHA2-SS) has been designed and synthesized. The prepared prodrugs could self-assemble into nanoparticles (SS NPs) with high DHA content (> 90%) and robust stability. These SS NPs display sensitive redox responsive capability and can release DHA under the tumor heterogeneity microenvironment. SS NPs possess preferable antitumor therapeutic activity in contrast with free DHA. Moreover, the possible anti-cancer mechanism of SS NPs was investigated through RNA-seq analysis, bioinformatics and molecular biological method. SS NPs could induce apoptosis via mitochondrial apoptosis pathway, as well as glycolysis inhibition associate with the regulation of PI3K/AKT/HIF-1α signal path, which may offer an underlying therapeutic target for liver cancer. Our study highlights the potential of using redox responsive prodrug nanoparticles to treat cancer, meanwhile provides insights into the anti-cancer mechanism of DHA prodrug.

Dihydroartemisinin inhibits Lewis Lung carcinoma progression by inducing macrophages M1 polarization via AKT/mTOR pathway

Preclinical and clinical data show a close relationship between high infiltration of tumor-associated macrophages (TAMs) and a poor prognosis in most types of tumors, thus targeting TAMs stands out as promising anticancer immunotherapies. Recent studies have demonstrated the anti-tumor effects of artemisinin via enhancing anti-tumor immunity within tumor microenvironment, but the underlying mechanism is still not clear. In the present study we uncovered an important role of dihydroartemisinin (DHA) in regulating intratumoral TAM polarization and anti-tumor immune responses in mouse Lewis Lung carcinoma model. We found that DHA inhibited Lewis Lung carcinoma progress, moderately decreased the frequencies of TAMs within tumor stroma, and significantly increased CD86 expression while decreased CD206 expression on TAMs which indicates the role of DHA in polarizing TAMs into a M1-like phenotype. Then, our in vitro data confirmed that DHA dose-dependently promoted macrophage M1 phenotype transition by increasing M1 phenotype-related molecules, meanwhile decreasing the expression of M2 phenotype-related molecules. In addition, DHA increased proinflammatory cytokine production, enhanced the phagocytic capacity while decreased anti-inflammatory cytokine production. Finally, in order to prove that AKT/mTOR signaling potentially mediated DHA-induced macrophage differentiation, we used rapamycin to specifically block the activity of mTOR and stimulated macrophages under M1 stimuli. Our data clearly showed that rapamycin significantly decreased DHA-induced M1-related phenotypes and proinflammatory cytokine expression. In summary, our study highlighted DHA as one of future potential therapeutic options for the development of novel anticancer immunotherapies in lung cancer.

Dihydroartemisinin alleviates morphine-induced neuroinflammation in BV-2 cells

Morphine tolerance poses a great challenge for clinicians, whose pathogenesis has a close connection with microglial activation and neuroinflammation. Dihydroartemisinin (DHA) that derives from artemisinin, may serve as a potential anti-inflammatory drug. In this study, the effects as well as the underlying mechanism of DHA on suppressing microglial activation and neuroinflammation were explored. The microglial cell line BV-2 cells were induced by morphine and treated with DHA or minocycline. With the application of CCK-8, the cell viability was detected. Western blot was employed to assess the expressions of Ki67, IBa-1, and TLR4 and quantitative real-time PCR (qRT-PCR) was adopted to evaluate miRNA-16 (miR-16) expression. With the adoption of ELISA kits and qRT-PCR, the release of inflammatory cytokines was evaluated. Besides, luciferase reporter assay was applied to testify the binding relationship between miR-16 and TLR4. NF-κB expression was measured by immunofluorescence. DHA reduced cell viability and decreased protein expression of Ki67 and IBa-1 in morphine-induced BV-2 cells. Additionally, DHA contributed to the declined release of pro-inflammatory cytokines. miR-16 was down-regulated by morphine but was up-regulated by DHA concentration-dependently in BV-2 cells. The inhibition of miR-16 partly abolished the inhibitory effects of DHA on morphine-induced microglial activation and neuroinflammation. Moreover, TLR4 was found to be bound to miR-16, and the inhibitory effect of DHA on TLR4/NF-κB was partly reversed by miR-16 inhibition. In conclusion, DHA remarkably suppressed microglial activation and neuroinflammation through regulating miR-16-mediated TLR4/NF-κB signaling. This study may provide a new solution to improve clinical analgesic efficacy of morphine.

Dihydroartemisinin mediating PKM2-caspase-8/3-GSDME axis for pyroptosis in esophageal squamous cell carcinoma

Pyroptosis is a novel type of pro-inflammatory programmed cell death that has been strongly reported to be related to inflammation, immune, and cancer. Dihydroartemisinin (DHA) has good anti-tumor properties. However, the exact mechanism by which DHA induces pyroptosis to inhibit esophageal squamous cell carcinoma (ESCC) remains unclear. After applying DHA treatment to ESCC, we found that some dying cells exhibited the characteristic morphology of pyroptosis, such as blowing large bubbles from the cell membrane, accompanied by downregulation of pyruvate kinase isoform M2 (PKM2), activation of caspase-8/3, and production of GSDME-NT. Meanwhile, it was accompanied by an increased release of LDH and inflammatory factors (IL-18 and IL-1β). Both knockdown of GSDME and application of caspase-8/3 specific inhibitors (z-ITED-FMK/Ac-DEVD-CHO) significantly inhibited DHA-induced pyroptosis. However, the former did not affect the activation of caspase-3. In contrast, overexpression of PKM2 inhibited caspase-8/3 activation as well as GSDME-N production. Furthermore, both si-GSDME and OE-PKM2 inhibited DHA-induced pyroptosis in vivo and in vitro. Therefore, the results suggest that DHA can induce pyroptosis of ESCC cells via the PKM2-caspase-8/3-GSDME pathway. Implication: In this study, we identified new mechanism of DHA in inhibiting ESCC development and progression, and provide a potential therapeutic agent for the treatment of ESCC.

Dihydroartemisinin ameliorates retinal vascular dysfunction in diabetes mellitus via the FASN/Kmal-mTOR/SREBP1 feedback loop

Microvascular dysfunction is the primary aetiology of visual impairment caused by diabetic retinopathy (DR). Dihydroartemisinin (DHA), the active metabolite of the antimalarials artemisinins, exhibits antiangiogenic properties in numerous diseases. Here, we investigated the function and mechanisms of DHA as a vasculoprotective agent in DR. DHA exerted its protective effect on vascular injuries in diabetic mice and inhibited cell proliferation and tube formation in human retinal microvascular endothelial cells by decreasing the level of fatty acid synthase (FASN), enhancing the malonylation of mechanistic target of rapamycin (mTOR) at lysine 1218 (K1218) and attenuating the activation of mTOR complex 1 (mTORC1). Impressively, a chemosynthetic small interfering RNA against FASN and mutagenesis of K1218 of mTOR showed therapeutic potential in suppressing cell proliferation and tube formation induced by high glucose. Notably, suppression of mTORC1 kinase activity further inhibited FASN by reducing p70S6K phosphorylation to subsequently reduce the expression of sterol regulatory element binding protein 1, which interacted directly with the FASN promoter at nucleotide positions -64 and -55. In conclusion, our study elucidated the promising effects of FASN and malonylation on vascular injuries of DR and indicated the great potential of DHA as a therapeutic approach.

Dihydroartemisinin inhibits IL-6-induced epithelial-mesenchymal transition in laryngeal squamous cell carcinoma via the miR-130b-3p/STAT3/β-catenin signaling pathway

Objective

To explore whether dihydroartemisinin (DHA) can block interleukin (IL)-6-induced epithelial–mesenchymal transition (EMT) in laryngeal squamous cell carcinoma (LSCC).

Methods

The expression of SLUG, signal transducer and activator of transcription 3 (STAT3), and microRNA (miR)-130b-3p was measured. In addition, a dual-luciferase reporter assay was performed to examine the interaction of miR-130b-3p with STAT3.

Results

We found that IL-6 can promote EMT and invasion in LSCC cells, whereas DHA can inhibit these two processes. However, DHA alone does not influence EMT and cancer invasion. Furthermore, DHA upregulated miR-130b-3p, which can downregulate STAT3 and β-catenin protein expression and decrease the activity of the IL-6/STAT3 signaling pathway. Moreover, we found that miR-130b-3p can target STAT3 directly.

Conclusions

DHA can block IL-6-triggered EMT and invasion in LSCC, and during these processes, DHA increases miR-130b-3p expression to decrease the activation of the IL-6/STAT3 and β-catenin signaling pathways. These findings may provide new insights into strategies for suppressing and even preventing LSCC metastasis.

Loss of pro-apoptotic Bax and Bak increases resistance to dihydroartemisinin-mediated cytotoxicity in normoxia but not in hypoxia in HCT116 colorectal cancer cells

Tumor hypoxia is a major biological factor that drives resistance to chemotherapy and radiotherapy. We previously demonstrated that the pro-oxidative drug dihydroartemisinin (DHA) efficiently targeted normoxic and hypoxic cancer cells. Although well studied in normoxia, the mechanism behind DHA-mediated cytotoxicity in hypoxia is insufficiently explored. Here, we analyzed the effect of DHA in HCT116 wild type (wt) cells and in HCT116 Bax^-/-Bak^sh cells with a defective intrinsic apoptosis pathway. Normoxic HCT116 wt cells underwent apoptosis shortly after treatment with DHA. Autophagy-associated cell death contributes to short-term cytotoxicity of DHA in normoxia. These cells switched to an apoptosis- and autophagy-independent cell death after treatment with DHA in hypoxia and displayed similar long-term survival in response to DHA in normoxia and hypoxia. In HCT116 Bax^-/-Bak^sh cells, DHA induced cell cycle arrest shortly after treatment irrespective of oxygen levels. Later, HCT116 Bax^-/-Bak^sh cells induced a delayed cell death after treatment with DHA in hypoxia followed by return to normoxia, while treatment with DHA in normoxia was hardly toxic. We identified lower glutathione levels in hypoxic HCT116 cells which correlated with higher lipid peroxidation after treatment with DHA. Moreover, insufficient expression of Bax/Bak counteracted hypoxia-mediated downregulation of mitochondrial function, thereby adding to DHA-induced ROS production and lipid peroxidation in hypoxia. In summary, DHA-mediated cytotoxicity in normoxia depended on Bax/Bak expression, while cytotoxicity after treatment with DHA in hypoxia was regulated independently of Bax/Bak in HCT116 colorectal cancer cells.

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.

Dihydroartemisinin Induces O-GlcNAcylation and Improves Cognitive Function in a Mouse Model of Tauopathy

BACKGROUND

Tauopathies are a group of neurodegenerative disorders, including Alzheimer's disease (AD) and frontotemporal lobar degeneration with tau pathology. Hyperphosphorylation modification promotes tau protein misfolding and aggregation into neurofibrillary tangles, leading to impairments of synaptic plasticity and learning and memory. However, very limited therapeutic strategies are available.

OBJECTIVE

In the present study, we wanted to investigate the potential effects of Dihydroartemisinin (DHA) on tauopathies.

METHODS

We constructed adeno-associated virus carrying hTau cDNA (AAVhTau) to establish a mouse model of tauopathy through intrahippocampal microinjection. Using a combination of behavioral test, electrophysiological recording, and western blotting assay, we examined the neuroprotective effects of DHA on learning and memory deficits in mice with tauopathy.

RESULTS

DHA improved learning and memory and increased hippocampal CA1 long-term potentiation (LTP) in mice overexpressed human tau (hTau) in the hippocampus. More importantly, further study revealed that DHA could induce protein O-GlcNAcylation modification and reduce protein phosphorylation. O-GlcNAc transferase inhibitor alloxan could suppress DHA-induced protein O-GlcNAcylation, and subsequently prevent therapeutic effect of DHA on the deficits of learning and memory as well as synaptic plasticity in hTau mice.

CONCLUSION

These results indicate that DHA may exert neuroprotective role in tauopathy through a crosstalk between O-GlcNAcylation and phosphorylation, suggesting a potential therapeutic for learning and memory deficits associated with tau pathology.

Dietary dihydroartemisinin supplementation alleviates intestinal inflammatory injury through TLR4/NOD/NF-κB signaling pathway in weaned piglets with intrauterine growth retardation

The aim of present study was to evaluate whether diets supplemented with dihydroartemisinin (DHA) could alleviate intestinal inflammatory injury in weaned piglets with intrauterine growth retardation (IUGR). Twelve normal birth weight (NBW) piglets and 12 piglets with IUGR were fed a basal diet (NBW-CON and IUCR-CON groups), and another 12 piglets with IUGR were fed the basal diet supplemented with DHA at 80 mg/kg (IUGR-DHA group) from 21 to 49 d of age. At 49 d of age, 8 piglets with similar body weight in each group were sacrificed. The jejunal and ileal samples were collected for further analysis. The results showed that IUGR impaired intestinal morphology, increased intestinal inflammatory response, raised enterocyte apoptosis and reduced enterocyte proliferation and activated transmembrane toll-like receptor 4 (TLR4)/nucleotide-binding and oligomerization domain (NOD)/nuclear factor-κB (NF-κB) signaling pathway. Dihydroartemisinin inclusion ameliorated intestinal morphology, indicated by increased villus height, villus height-to-crypt depth ratio, villus surface area and decreased villus width of piglets with IUGR (P < 0.05). Compared with NBW piglets, IUGR piglets supplemented with DHA exhibited higher apoptosis index and caspase-3 expression, and lower proliferation index and proliferating cell nuclear antigen expression in the intestine (P < 0.05). Dihydroartemisinin supplementation attenuated the intestinal inflammation of piglets with IUGR, indicated by increased concentrations of intestinal inflammatory cytokines and lipopolysaccharides (P < 0.05). In addition, DHA supplementation down-regulated the related mRNA expressions of TLR4/NOD/NF-κB signaling pathway and upregulated mRNA expressions of negative regulators of TLR4 and NOD signaling pathway in the intestine of piglets with IUGR (P < 0.05). Piglets in the IUGR-DHA group showed lower protein expressions of TLR4, phosphorylated NF-κB (pNF-κB) inhibitor α, nuclear pNF-κB, and higher protein expression of cytoplasmic pNF-κB in the intestine than those in the IUGR-CON group (P < 0.05). In conclusion, DHA supplementation could improve intestinal morphology, regulate enterocyte proliferation and apoptosis, and alleviate intestinal inflammation through TLR4/NOD/NF-κB signaling pathway in weaned piglets with IUGR.

Dihydroartemisinin regulates lipid droplet metabolism in hepatic stellate cells by inhibiting lncRNA-H19-induced AMPK signal

Activation of hepatic stellate cells (HSCs) is a central event in the pathogenesis of liver fibrosis and is often accompanied by the disappearance of lipid droplets (LDs). Although interference with LD metabolism can effectively reverse the activation of HSCs, there is currently no effective therapy for liver fibrosis. Our previous evidence indicates that long non-coding RNA (lncRNA)-H19 plays an essential role in LD metabolism of HSC. In this study, we investigated the potential molecular mechanism of dihydroartemisinin (DHA) inhibits LD metabolism and liver fibrosis by regulating H19-AMPK pathway. We found that DHA restores LDs content in activated HSCs via reducing the transcription of H19 driven by hypoxia inducible factor 1 subunit alpha (HIF1α) and inhibiting the lipid oxidation signal mediated by AMP-activated protein kinase (AMPK) phosphorylation. In vivo experiments, we have proved that DHA reduced the deposition of extracellular matrix (ECM) and reduce the level of liver fibrosis in CCl₄-induced liver fibrosis of mice. In summary, our results emphasize the importance of H19 in liver fibrosis and the potential of DHA to regulate H19 to treat liver fibrosis, providing a new direction for the prevention and treatment of liver fibrosis.

Artemisia annua L. extracts inhibit the in vitro replication of SARS-CoV-2 and two of its variants

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. has been used for millennia in Southeast Asia to treat "fever". Many infectious microbial and viral diseases have been shown to respond to A. annua and communities around the world use the plant as a medicinal tea, especially for treating malaria.

AIM OF THE STUDY

SARS-CoV-2 (the cause of Covid-19) globally has infected and killed millions of people. Because of the broad-spectrum antiviral activity of artemisinin that includes blockade of SARS-CoV-1, we queried whether A. annua suppressed SARS-CoV-2.

MATERIALS AND METHODS

Using Vero E6 and Calu-3 cells, we measured anti SARS-CoV-2 activity against fully infectious virus of dried leaf extracts of seven cultivars of A. annua sourced from four continents. IC50s were calculated and defined as the concentrations that inhibited viral replication by 50%; CC50s were also calculated and defined as the concentrations that kill 50% of cells.

RESULTS

Hot-water leaf extracts based on artemisinin, total flavonoids, or dry leaf mass showed antiviral activity with IC₅₀ values of 0.1-8.7 μM, 0.01-0.14 μg, and 23.4-57.4 μg, respectively. Antiviral efficacy did not correlate with artemisinin or total flavonoid contents of the extracts. One dried leaf sample was >12 years old, yet its hot-water extract was still found to be active. The UK and South African variants, B1.1.7 and B1.351, were similarly inhibited. While all hot water extracts were effective, concentrations of artemisinin and total flavonoids varied by nearly 100-fold in the extracts. Artemisinin alone showed an estimated IC₅₀ of about 70 μM, and the clinically used artemisinin derivatives artesunate, artemether, and dihydroartemisinin were ineffective or cytotoxic at elevated micromolar concentrations. In contrast, the antimalarial drug amodiaquine had an IC₅₀ = 5.8 μM. Extracts had minimal effects on infection of Vero E6 or Calu-3 cells by a reporter virus pseudotyped by the SARS-CoV-2 spike protein. There was no cytotoxicity within an order of magnitude above the antiviral IC₉₀ values.

CONCLUSIONS

A. annua extracts inhibit SARS-CoV-2 infection, and the active component(s) in the extracts is likely something besides artemisinin or a combination of components that block virus infection at a step downstream of virus entry. Further studies will determine in vivo efficacy to assess whether A. annua might provide a cost-effective therapeutic to treat SARS-CoV-2 infections.

Structure-activity relationship study of dihydroartemisinin C-10 hemiacetal derivatives as Toll-like receptor 4 antagonists

Dihydroartemisinin (DHA), a natural product isolated from the traditional Chinese herb Artemisia annua and one of the clinical frontline drugs against malarial infections, has recently been discovered as a Toll-like Receptor 4 (TLR4) antagonist. However, the TLR4 antagonistic activity of DHA is modest and it exhibits cellular toxicity. In this work, the structure-activity relationship (SAR) of DHA as TLR4 antagonist was explored. Since destroying the sesquiterpene endoperoxide scaffold substantially compromised the TLR4 antagonistic activity and molecular dynamics analysis showed that the C-10 hydroxyl group formed a hydrogen bond with E72 of myeloid differentiation factor 2 (MD2) to prevent it moving deeper into MD2, SAR of DHA was focused on the C-10 hemiacetal position. With extending the length of the linear alkane chain at C10 position, the TLR4 antagonistic activity of DHA analogs increased first and then decreased with the best TLR4 antagonism occurring at the length of the carbon chain of 3-4 carbons. In contrast, the cellular toxicity of DHA analogs was raised with the increasing length of the linear alkane chain. The TLR4 antagonistic activity of DHA derivatives with substituted halogen as the terminal functional group decreased with the decrease of electronegativity of the substituted halogen, which implies the electron-rich functional group at the end of the alkane chain appears preferred. Therefore, DHA derivative 2k with alkynyl as the end functional group, exhibited 14 times more potent TLR4 antagonistic activity than DHA. Moreover, 2k showed less cellular toxicity than DHA. Cellular signaling characterizations indicated that 2k inhibited LPS-induced TLR4 dimerization and endocytosis and suppressed LPS-induced NF-κB but not MAPKs activation, culminating in blocking LPS-induced TLR4 signaling downstream pro-inflammatory factors NO and IL-1β. Further, 2k was active in vivo; it significantly increased and prolonged morphine analgesia. Collectively, this study provides a structural guidance to reposition DHA derivatives as TLR4 antagonists.

Comments on "Dihydroartemisinin induces pyroptosis by promoting the AIM2/caspase-3/DFNA5 axis in breast cancer cells."

We read the article "Dihydroartemisinin induces pyroptosis by promoting the AIM2/caspase-3/DFNA5 axis in breast cancer cells" published in Chemico-Biological Interactions. Authors revealed that dihydroartemisinin induced pyroptosis through activating the AIM2/caspase-3/DFNA5 pathway in breast cancer cells. However, some issues in this paper need to be commented. Authors suggested that dihydroartemisinin activated AIM2/caspase-3/DFNA5 axis in MCF-7 cell line. However, previous studies have confirmed that MCF-7 cell line does not express the caspase-3 protein. This makes us confused.

Dihydroartemisinin overcomes the resistance to osimertinib in EGFR-mutant non-small-cell lung cancer

Osimertinib, a third-generation EGFR tyrosine kinase inhibitor (TKI), is commonly used to treat EGFR-mutant non-small-cell lung cancer (NSCLC). However, acquired resistance to mutant EGFR (T790M) can evolve following osimertinib treatment. High reactive oxygen species (ROS) levels in lung cancer cells can influence heme levels and have an impact on osimertinib resistance. Here, we found that heme levels were increased in osimertinib resistant EGFR-mutant NSCLC cell lines and plasma heme levels were also elevated in osimertinib-treated EGFR-mutant NSCLC patients. The antimalarial drug dihydroartemisinin (DHA), which has anticancer effects and requires heme, was tested to determine its potential to revert osimertinib resistance. DHA downregulated the expression of heme oxygenase 1 and inhibited cell proliferation in osimertinib-resistant EGFR-mutant NSCLC cells (PC9-GR4-AZD1), which was further enhanced by addition of 5-aminolevulinic acid, protoporphyrin IX and hemin. DHA was synergistic with osimertinib in inhibiting cell proliferation and colony formation of all osimertinib-resistant cell lines tested. Combination treatment with osimertinib and DHA also increased the levels of ROS, downregulated the phosphorylation or protein levels of several RTKs that often are overexpressed in osimertinib-resistant EGFR-mutant NSCLC cells, and inhibited tumor growth without toxicity in a PC9-GR4-AZD1 xenograft mouse model. The results suggest that DHA is able to reverse the resistance to osimertinib in EGFR-mutant NSCLC by elevating ROS level and impair heme metabolism.

Effect of fresh pomegranate juice on the pharmacokinetic profile of artemether: An open-label, randomized, 2- period crossover study in healthy human volunteers

This study was designed to evaluate the effect of fresh pomegranate (Punica granatum L.) juice on the pharmacokinetic profile of artemether in healthy volunteers. A randomized, open-label, crossover study was conducted on healthy subjects (n = 26). Each volunteer received 250 mL of fresh pomegranate juice twice daily for 2 weeks. On day 14, they were administered a single oral dose of artemether (80 mg) with either water or 250 mL of pomegranate juice. Thirteen blood samples were collected up to 12 h and 6 electrocardiograms were recorded. Plasma concentrations of artemether and its metabolite dihydroartemisinin were analyzed by a noncompartmental method using LC-MS/MS. The lower limit of detection (LLOD) and lower limit of quantification (LLOQ) for artemether were estimated as 0.3 and 0.8 ng/mL, respectively, while for dihydroartemisinin it was 0.2 and 0.6 ng/mL, respectively. The pharmacokinetic parameters of artemether and dihydroartemisinin were not significantly altered when co-administered with the fresh pomegranate juice. AUC _(0-∞) was slightly increased from 742 to 859 ng/mL for artemether [geometric mean ratio: 1.14 (95 % CI, 1.08,1.18); P = 0.45] and from 699 to 818 ng/mL for dihydroartemisinin [geometric mean ratio: 1.15 (95 % CI, 1.09, 1.15); P = 0.4]. Difference in C_max for artemether was also statistically non-significant [173 vs 195 ng/mL; geometric mean ratio: 1.09 (95 % CI, 0.91, 1.15); P = 0.61]. Likewise, elimination half-life (t_1/2) for both artemether and dihydroartemisinin remained unchanged (P = 0.43 and 0.31, respectively). In addition, there was no significant difference in t_max for artemether (P = 0.66) and its metabolite (P = 0.65). In conclusion, findings of the present study demonstrated that the administration of pomegranate juice had no significant effect on the pharmacokinetic profile of artemether.

Dihydroartemisinin alleviates skin fibrosis and endothelial dysfunction in bleomycin-induced skin fibrosis models

OBJECTIVE

The present study was to investigate whether dihydroartemisinin (DHA), which is a highly effective and safe drug in the treatment of malaria, could be repurposed for the treatment of skin fibrosis and vascular dysfunction in systemic sclerosis (SSc).

METHODS

The value of DHA was determined using a bleomycin-induced model of skin fibrosis. mRNA transcriptome analysis was performed, and the targets of DHA on fibroblasts were identified. Immunofluorescence staining was used to identify dermal vessels undergoing endothelial-to-mesenchymal transition (EndoMT). Autophagic flux was detected by western blot and mRFP-GFP-LC3 adenovirus vector transfection.

RESULTS

Both systemic and topical administration of DHA decreased dermal thickness and collagen deposition and alleviated EndoMT in bleomycin-induced skin fibrosis mice model. Treatment of human umbilical vein endothelial cells (HUVECs) with TGF-β1 resulted in the acquisition of the activation marker (α-SMA) and loss of endothelial markers (CD31 and VE-cadherin), a process that was restored by DHA. DHA significantly suppressed skin fibroblast activation and collagen-1 production mainly through regulating PI3K-Akt pathway. DHA also induced fibroblast autophagic flux and that autophagy dependently suppressed collagen-1 production.

CONCLUSION

The results of the present study revealed that oral and topical DHA administration ameliorated tissue fibrosis and protected dermal blood vessels from bleomycin-induced EndoMT. Our study has elucidated the value of repurposing DHA for the treatment of SSc. Key Points • Oral or topical usage of DHA alleviated dermal fibrosis and EndoMT in bleomycin-induced skin fibrosis mice models. • DHA autophagy dependently inhibited fibroblast activation and collagen deposition via PI3K-ATK pathway. • DHA inhibited EndoMT of HUVECs induced by TGF-β1 by the downregulation of α-SMA and the upregulation of CD31 and VE-cadherin.

Discovery of novel dihydroartemisinin-cinnamic hybrids inducing lung cancer cells apoptosis via inhibition of Akt/Bad signal pathway

A series of dihydroartemisinin-cinnamic acid hybrids were designed, synthesized and evaluated. Most of the tested compounds showed enhanced anti-proliferative activities than artemisinin and dihydroartemisinin, among which 16 g had the superior potency with IC₅₀ values ranging from 5.07 μM to 7.88 μM against four tested cancer cell lines. The cell cycle arrest revealed that 16 g induced A549 cell cycle arrest at G0/G1 phase via regulation of G1-related protein expression (Cdk4). Further mechanism studies reveal that 16 g induced A549 cells apoptosis via inhibiting Akt/Bad pathway. Moreover, 16 g depolarized the mitochondria membrane potentials and induced ROS generation in A549. Additionally, 16 g blocked migration of A549 cells in a concentration-dependent manner. What's more, 16 g is barely nontoxic to zebrafish embryos. Overall, the cell cycle arrest, inhibition of Akt/Bad signal pathway, ROS generation and migration blocked might explain the potent anti-proliferative activities of these compounds.

Dihydroartemisinin prompts amplification of photodynamic therapy-induced reactive oxygen species to exhaust Na/H exchanger 1-mediated glioma cells invasion and migration

Photodynamic therapy (PDT) is a promising glioma therapy; however, its efficacy is compromised due to the PDT-induced reactive oxygen species (ROS) production being limited by the local hypoxic tumor microenvironment. Furthermore, Hypoxia activates sodium/hydrogen exchanger 1 (NHE1), an essential component for tumor progression and metastasis, enables glioma cells (GC) to escape PDT-mediated phototoxicity via increased H⁺ extrusion. However, interactions between NHE1 expression with ROS level involving response of GC remain unclear. Dihydroartemisinin (DHA), a ROS generator, has extensive anti-tumor effects. This study aimed to explore whether PDT along with DHA could amplify the total ROS levels and diminish GC invasion and migration by inhibiting NHE1 expression. Proliferation and invasion of U251 and LN229 cells were evaluated under different treatments using cell counting Kit-8 (CCK-8), transwell, and wound healing assays. ROS levels were measured using fluorescence probes and flow cytometry. NHE1 levels were detected by immunofluorescence and western blotting. Co-treatment effects and molecular events were further confirmed in a bilateral tumor-bearing nude mouse model. PDT with synergistic DHA significantly increased the total abundance of ROS to further suppress the invasion and migration of GC by reducing NHE1 levels in vitro. Using a bilateral glioma xenograft mouse model with primary and recurrent gliomas, we found that PDT markedly suppressed primary tumor growth, while PDT in synergy with DHA also suppressed recurrent tumors, and improved overall survival by regulating the ROS-NHE1 axis. No evident side effects were observed. Our results suggest that PDT with DHA can amplify the total ROS levels to weaken GC invasion and migration by suppressing NHE1 expression in vitro and in vivo, thus abolishing the resistance of GC to PDT. The synergistic therapy of PDT and DHA therefore represents a more efficient and safe strategy for comprehensive glioma treatment.

Therapeutic effects of dihydroartemisinin in multiple stages of colitis-associated colorectal cancer

Colitis-associated colorectal cancer (CAC) develops from chronic intestinal inflammation. Dihydroartemisinin (DHA) is an antimalarial drug exhibiting anti-inflammatory and anti-tumor effects. Nonetheless, the therapeutic effects of DHA on CAC remain unestablished.

Methods: Mice were challenged with azoxymethane (AOM) and dextran sulfate sodium (DSS) to establish CAC models. DHA was administered via oral gavage in different stages of CAC models. Colon and tumor tissues were obtained from the AOM/DSS models to investigate inflammatory responses and tumor development. Inflammatory cytokines in the murine models were detected through qRT-PCR and ELISA. Toll-like receptor 4 (TLR4) signaling-related proteins were detected by western blot. Macrophage infiltration was measured using immunostaining analysis, and apoptosis in the colon cancer cells was detected by flow cytometry and western blot.

Results: DHA inhibited inflammatory responses in the early stage of the AOM/DSS model and subsequent tumor formation. In the early stage, DHA reversed macrophage infiltration in colon mucosa and decreased the expression of pro-inflammatory cytokines. DHA inhibited the activation of macrophage by suppressing the TLR4 signal pathway. In the late stage of CAC, DHA inhibited tumor growth by enhancing cell cycle arrest and apoptosis in tumor cells. Administration of DHA during the whole period of the AOM/DSS model generated an addictive effect based on the inhibition of inflammation and tumor growth, thereby improving the therapeutic effect of DHA on CAC.

Conclusion: Our study indicated that DHA could be a potent agent in managing the initiation and development of CAC without obvious side effects, warranting further clinical translation of DHA for CAC treatment.

Cannabidiol-dihydroartemisinin conjugates for ameliorating neuroinflammation with reduced cytotoxicity

Cannabidiol (CBD) and dihydroartemisinin (DHA) can alleviate neuroinflammatory responses. However, they show cytotoxicity, which severely limits their therapeutic windows. Therefore, there is a great need to develop neuroprotective agents with improved safety. Drug-drug conjugate is an emerging approach for enhancing therapeutic index. Herein, the development, synthesis, and the pharmacological characterization of CBD-DHA conjugates were performed. Meanwhile, the combination of CBD and DHA as separate entities was also quantitatively analyzed for direct comparison with CBD-DHA conjugates. In this study, BV-2 microglial cell line was used to mimic primary microglia and the effects of CBD, DHA, the combination of CBD and DHA, as well as CBD-DHA conjugates on LPS-activated signaling molecules and pro-inflammatory factors were assessed. The interaction of CBD and DHA in inhibiting LPS-induced nitric oxide (NO) production was found to be additive. In contrast, DHA was found to synergize with CBD in inhibiting BV-2 cellular viability which implies that the combination of CBD and DHA amplifies their cytotoxicity. CBD-DHA conjugate C3D eliminated the cytotoxicity associated with single CBD/DHA use without significantly compromising the anti-neuroinflammation activity. C3D was more potent than C2D and C4D in inhibiting LPS-induced NO and mRNAs of iNOS and IL-1β, which implies that the linker length is critical for CBD-DHA conjugates' anti-inflammatory activities. Further signaling characterizations showed that C3D inhibited LPS-induced NF-κB but not MAPKs activation in BV-2 cells, therefore blocking LPS-induced neuroinflammation. This work provides a good example that conjugated drug-drug approach may improve the therapeutic index by increasing the maximum tolerated concentration/dose compared to traditional combination strategy.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Dihydroartemisinin induces pyroptosis by promoting the AIM2/caspase-3/DFNA5 axis in breast cancer cells

BACKGROUND

Breast cancer is a complex disease. Recent research has examined the anticancer effects of dihydroartemisinin (DHA) on breast cancer. However, the molecular mechanism of the antitumour effect of DHA is unclear.

METHODS

MCF-7 and MDA-MB-231 cell lines were used for in vitro research. BALB/c nude mice were used to establish breast cancer xenografts. The mRNA and protein levels were analysed by qRT-PCR and western blotting, respectively. Flow cytometry was performed to examine cell apoptosis. ELISA kits were used to evaluate the production of interleukin-1β (IL-1β) and IL-18. LDH and ATP release were individually measured with the corresponding kits. A colony formation assay was used to examine the proliferation of breast cancer cells.

RESULTS

DHA inhibited proliferation and induced pyroptosis in breast cancer cells. Mechanistically, DHA activated the expression of absent in melanoma 2 (AIM2), caspase-3 and gasdermin E (DFNA5). In addition, AIM2 promoted DFNA5 expression by activating caspase-3. Knockdown of AIM2 and DFNA5 significantly enhanced breast cancer cell resistance to DHA. In vivo experiments showed that the tumorigenicity of breast cancer cells was significantly suppressed by DHA. Moreover, the AIM2/caspase-3/DFNA5 axis was activated by DHA and then induced pyroptosis.

CONCLUSIONS

Our findings indicate that DHA inhibits tumorigenesis by inducing pyroptosis in breast cancer cells, highlighting a promising therapeutic strategy for breast cancer.

N-alkyl triphenylvinylpyridinium conjugated dihydroartemisinin perturbs mitochondrial functions resulting in enhanced cancer versus normal cell toxicity

Dihydroartemisinin (DHA) is an FDA-approved antimalarial drug that has been repurposed for cancer therapy because of its preferential antiproliferative effects on cancer versus normal cells. Mitochondria represent an attractive target for cancer therapy based on their regulatory role in proliferation and cell death. This study investigates whether DHA conjugated to innately fluorescent N-alkyl triphenylvinylpyridinium (TPVP) perturbs mitochondrial functions resulting in a differential toxicity of cancer versus normal cells. TPVP-DHA treatments resulted in a dose-dependent toxicity of human melanoma and pancreatic cancer cells, whereas normal human fibroblasts were resistant to this treatment. TPVP-DHA treatments resulted in a G₁-delay of the cancer cell cycle, which was also associated with a significant inhibition of the mTOR-metabolic and ERK1/2-proliferative signaling pathways. TPVP-DHA treatments perturbed mitochondrial functions, which correlated with increases in mitochondrial fission. In summary, TPVP mediated mitochondrial targeting of DHA enhanced cancer cell toxicity by perturbing mitochondrial functions and morphology.

Artemisia annua L. extracts inhibit the in vitro replication of SARS-CoV-2 and two of its variants

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia annua L. has been used for millennia in Southeast Asia to treat "fever". Many infectious microbial and viral diseases have been shown to respond to A. annua and communities around the world use the plant as a medicinal tea, especially for treating malaria.

AIM OF THE STUDY

SARS-CoV-2 (the cause of Covid-19) globally has infected and killed millions of people. Because of the broad-spectrum antiviral activity of artemisinin that includes blockade of SARS-CoV-1, we queried whether A. annua suppressed SARS-CoV-2.

MATERIALS AND METHODS

Using Vero E6 and Calu-3 cells, we measured anti viral activity SARS-CoV-2 activity against fully infectious virusof dried leaf extracts of seven cultivars of A. annua sourced from four continents. IC50s were calculated and defined as (the concentrations that inhibited viral replication by 50%.) and CC50s (the concentrations that kill 50% of cells) were calculated.

RESULTS

Hot-water leaf extracts based on artemisinin, total flavonoids, or dry leaf mass showed antiviral activity with IC50 values of 0.1-8.7 μM, 0.01-0.14 μg, and 23.4-57.4 μg, respectively. Antiviral efficacy did not correlate with artemisinin or total flavonoid contents of the extracts. One dried leaf sample was >12 years old, yet the hot-water extract was still found to be active. The UK and South African variants, B1.1.7 and B1.351, were similarly inhibited. While all hot water extracts were effective, concentrations of artemisinin and total flavonoids varied by nearly 100-fold in the extracts. Artemisinin alone showed an estimated IC50 of about 70 μM, and the clinically used artemisinin derivatives artesunate, artemether, and dihydroartemisinin were ineffective or cytotoxic at elevated micromolar concentrations. In contrast, the antimalarial drug amodiaquine had an IC50 = 5.8 μM. Extracts had minimal effects on infection of Vero E6 or Calu-3 cells by a reporter virus pseudotyped by the SARS-CoV-2 spike protein. There was no cytotoxicity within an order of magnitude above the antiviral IC90 values.

CONCLUSIONS

A. annua extracts inhibit SARS-CoV-2 infection, and the active component(s) in the extracts is likely something besides artemisinin or a combination of components that block virus infection at a step downstream of virus entry. Further studies will determine in vivo efficacy to assess whether A. annua might provide a cost-effective therapeutic to treat SARS-CoV-2 infections.