Dihydroartemisinin induces apoptosis in human gastric cancer cell line BGC-823 through activation of JNK1/2 and p38 MAPK signaling pathways

Targeting PI3K/AKT/mTOR and MAPK Signaling Pathways in Gastric Cancer

Gastric cancer (GC) is the fourth leading cause of death worldwide, with more than 1 million cases diagnosed every year. Helicobacter pylori represents the main risk factor, being responsible for 78% of the cases. Increased amounts of salt, pickled food, red meat, alcohol, smoked food, and refined sugars negatively affect the stomach wall, contributing to GC development. Several gene mutations, including PIK3CA, TP53, ARID1A, CDH1, Ras, Raf, and ERBB3 are encountered in GC pathogenesis, leading to phosphatidylinositol 3-kinase (PI3K) protein kinase B (AKT)/mammalian target of rapamycin (mTOR)-PI3K/AKT/mTOR-and mitogen-activated protein kinase (MAPK) signaling pathway activation and promoting tumoral activity. Helicobacter pylori, growth factors, cytokines, hormones, and oxidative stress also activate both pathways, enhancing GC development. In clinical trials, promising results have come from monoclonal antibodies such as trastuzumab and ramucirumab. Dual inhibitors targeting the PI3K/AKT/mTOR and MAPK signaling pathways were used in vitro studies, also with promising results. The main aim of this review is to present GC incidence and risk factors and the dysregulations of the two protein kinase complexes together with their specific inhibitors.

Anti-Apoptotic Effect of Chrysophanol Isolated from Cassia tora Seed Extract on Blue-Light-Induced A2E-Loaded Human Retinal Pigment Epithelial Cells

The seeds of Cassia tora (C. tora) species mainly contain anthraquinone, anthraquinone glycoside, and naphthalene derivatives. We investigated the anti-apoptotic effects of C. tora seed extract and its isolated compounds on blue-light-induced lipofuscin (A2E)-loaded human retinal pigment epithelial (RPE) cells. For analysis of the C. tora extract, high-performance liquid chromatography method was used. A2E-loaded human retinal pigment epithelial cells and blue light were used to create excessive photo-oxidation to induce cell death. Lactate dehydrogenase (LDH) assay was used to measure cell cytotoxicity, and the mRNA expression of genes involved in apoptosis was examined to evaluate the mechanism of cell death. C. tora extract, n-hexane fraction, and chrysophanol were found to inhibit apoptotic cell death. Additionally, C. tora extract, n-hexane fraction, and chrysophanol reduced the mRNA expression of genes involved in the apoptosis pathway. C. tora and chrysophanol were considered to inhibit apoptosis and oxidative stress response. The major component of C. tora has a protective effect against apoptosis. The ingredients of C. tora can be used as therapeutic substances or to prevent diseases caused by the excessive oxidation of A2E substances in the retina, such as in age-related macular degeneration.

Molecular mechanisms underlying the action of carcinogens in gastric cancer with a glimpse into targeted therapy

BACKGROUND

Gastric cancer imposes a substantial global health burden despite its overall incidence decrease. A broad spectrum of inherited, environmental and infectious factors contributes to the development of gastric cancer. A profound understanding of the molecular underpinnings of gastric cancer has lagged compared to several other tumors with similar incidence and morbidity rates, owing to our limited knowledge of the role of carcinogens in this malignancy. The International Agency for Research on Cancer (IARC) has classified gastric carcinogenic agents into four groups based on scientific evidence from human and experimental animal studies. This review aims to explore the potential comprehensive molecular and biological impacts of carcinogens on gastric cancer development and their interactions and interferences with various cellular signaling pathways.

CONCLUSIONS

In this review, we highlight recent clinical trial data reported in the literature dealing with different ways to target various carcinogens in gastric cancer. Moreover, we touch upon other multidisciplinary therapeutic approaches such as surgery, adjuvant and neoadjuvant chemotherapy. Rational clinical trials focusing on identifying suitable patient populations are imperative to the success of single-agent therapeutics. Novel insights regarding signaling pathways that regulate gastric cancer can potentially improve treatment responses to targeted therapy alone or in combination with other/conventional treatments. Preventive strategies such as control of H. pylori infection through eradication or immunization as well as dietary habit and lifestyle changes may reduce the incidence of this multifactorial disease, especially in high prevalence areas. Further in-depth understanding of the molecular mechanisms involved in the role of carcinogenic agents in gastric cancer development may offer valuable information and update state-of-the-art resources for physicians and researchers to explore novel ways to combat this disease, from bench to bedside. A schematic outlining of the interaction between gastric carcinogenic agents and intracellular pathways in gastric cancer H. pylori stimulates multiple intracellular pathways, including PI3K/AKT, NF-κB, Wnt, Shh, Ras/Raf, c-MET, and JAK/STAT, leading to epithelial cell proliferation and differentiation, apoptosis, survival, motility, and inflammatory cytokine release. EBV can stimulate intracellular pathways such as the PI3K/Akt, RAS/RAF, JAK/STAT, Notch, TGF-β, and NF-κB, leading to cell survival and motility, proliferation, invasion, metastasis, and the transcription of anti-apoptotic genes and pro-inflammatory cytokines. Nicotine and alcohol can lead to angiogenesis, metastasis, survival, proliferation, pro-inflammatory, migration, and chemotactic by stimulating various intracellular signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, ROS, and JAK/STAT. Processed meat contains numerous carcinogenic compounds that affect multiple intracellular pathways such as sGC/cGMP, p38 MAPK, ERK, and PI3K/AKT, leading to anti-apoptosis, angiogenesis, metastasis, inflammatory responses, proliferation, and invasion. Lead compounds may interact with multiple signaling pathways such as PI3K/AKT, NF-κB, Ras/Raf, DNA methylation-dependent, and epigenetic-dependent, leading to tumorigenesis, carcinogenesis, malignancy, angiogenesis, DNA hypermethylation, cell survival, and cell proliferation. Stimulating signaling pathways such as PI3K/Akt, RAS/RAF, JAK/STAT, WNT, TGF-β, EGF, FGFR2, and E-cadherin through UV ionizing radiation leads to cell survival, proliferation, and immortalization in gastric cancer. The consequence of PI3K/AKT, NF-κB, Ras/Raf, ROS, JAK/STAT, and WNT signaling stimulation by the carcinogenic component of Pickled vegetables and salted fish is the Warburg effect, tumorigenesis, angiogenesis, proliferation, inflammatory response, and migration.

Sesquiterpenes from Artemisia annua and Their Cytotoxic Activities

Artemisia annua is a well-known traditional Chinese medicine. Due to its highest antimalarial efficacy, China has a long history of cultivating A. annua, and it is used for “clearing heat and detoxicating”. Several, studies have shown that the A. annua extract exerts cytotoxicity. In order to clarify the basis of the cytotoxic effect of A. annua, 18 sesquiterpenes were isolated from the herb, including 2 new sesquiterpenes and 16 known analogues. The structures of new compounds were elucidated by comprehensive spectroscopic analyses, including HR-ESI-MS, NMR experiments, single-crystal X-ray, and DP4+ and electronic circular dichroism (ECD) calculations. Cytotoxic activity screening revealed three compounds that exhibited cytotoxicity in a dose-dependent manner. Additional exploration showed that compound 5 significantly inhibited the proliferation of CT26 and HCT116 cells and induced apoptosis of HCT116 cells after 24 h. These chemical constituents contributed to elucidating the mechanism of action of the cytotoxic activity of A. annua.

A Network Pharmacology Perspective Investigation of the Pharmacological Mechanisms of the Herbal Drug FDY003 in Gastric Cancer

Gastric cancer (GC) is one of the most common and deadly malignant tumors worldwide. While the application of herbal drugs for GC treatment is increasing, the multicompound–multitarget pharmacological mechanisms involved are yet to be elucidated. By adopting a network pharmacology strategy, we investigated the properties of the anticancer herbal drug FDY003 against GC. We found that FDY003 reduced the viability of human GC cells and enhanced their chemosensitivity. We also identified 8 active phytochemical compounds in FDY003 that target 70 GC-associated genes and proteins. Gene ontology (GO) enrichment analysis suggested that the targets of FDY003 are involved in various cellular processes, such as cellular proliferation, survival, and death. We further identified various major FDY003 target GC-associated pathways, including PIK3-Akt, MAPK, Ras, HIF-1, ErbB, and p53 pathways. Taken together, the overall analysis presents insight at the systems level into the pharmacological activity of FDY003 against GC.

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

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

Artemether confers neuroprotection on cerebral ischemic injury through stimulation of the Erk1/2-P90rsk-CREB signaling pathway

Ischemic stroke is one of the leading causes of death and disability among adults. Despite the economic burden of the disease, available treatment options are still very limited. With the exception of anti-thrombolytics and hypothermia, current therapies fail to reduce neuronal injury, neurological deficits and mortality rates, suggesting that the development of novel and more effective therapies against ischemic stroke is urgent. In the present study, we found that artemether, which has been used in the clinic as an anti-malarial drug, was able to improve the neurological deficits, attenuate the infarction volume and the brain water content in a middle cerebral artery occlusion (MCAO) animal model. Furthermore, artemether treatment significantly suppressed cell apoptosis, stimulated cell proliferation and promoted the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), P90^rsk and cAMP responsive element-binding protein (CREB). Artemether protective effect was attenuated by PD98059, an ERK1/2 inhibitor, administration. Similarly, in oxygen-glucose deprivation/reperfusion (OGD/RP) cell models, artemether pre-treatment induced the suppression of the intracellular ROS, the down-regulation of LDH activity, the reduction of caspase 3 activity and of the apoptosis cell rate and reversed the decrease of mitochondrial membrane potential. As with MCAO animal model, artemether promoted the activation of Erk1/2-P90^rsk-CREB signaling pathway. This effect was blocked by the inhibition or knock-down of ERK1/2. The present study provides evidences of the neuroprotective effect of artemether unravelling its potential as a new therapeutic candidate for the prevention and treatment of stroke.

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Artemether conferred neuroprotection in a middle cerebral artery occlusion (MCAO) animal model.

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Artemether conferred neuroprotection on oxygen-glucose deprivation/reperfusion-induced cell injury model.

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Artemether promoted the activation of Erk1/2-P90^rsk-CREB signaling pathway in vitro and in vivo.

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.

Dihydroartemisinin inhibits the tumorigenesis and invasion of gastric cancer by regulating STAT1/KDR/MMP9 and P53/BCL2L1/CASP3/7 pathways

Dihydroartemisinin (DHA), an effective antimalarial drug, has been widely investigated as an anti-tumor agent. Although previous studies have indicated the potential therapeutic effects of DHA on multiple malignancies, its detailed molecular mechanisms in gastric cancer (GC) are still undocumented. In the present study, we applied network pharmacology and bioinformatics (gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses) to obtain the collective targets of DHA and GC and analyzed their involvement in constructing a protein-protein interaction (PPI) network. The top 10% hub targets in this network were identified, and TCGA database was utilized for the single gene analysis of their correlation with the prognosis of GC. CCK8, EdU, Transwell, and flow cytometry analyses were conducted, and subcutaneous xenograft tumor models were constructed to assess the effects of DHA on the tumorigenesis and invasion of GC. Furthermore, the targets of DHA were verified by molecular docking, quantitative real-time PCR (qPCR) and western blot analyses in GC cells. The results indicated that the common targets of DHA and GC were enriched in multiple cancer-related pathways including KDR, STAT1 and apoptosis signaling pathways, where the core genes included KDR, MMP9, STAT1, TP53, CASP3/7 and BCL2L1. The lowered expression of KDR and increased expression of TP53 and CASP7 harbored a favorable survival for patients with GC patients. CASP7 showed a positive correlation with CASP3 but a negative correlation with KDR and could be regarded as an independent protective factor for overall survival in GC. Moreover, DHA treatment induced cell apoptosis and suppressed the cell proliferation, DNA synthesis, cycle progression and invasive capabilities both in vitro and in vivo. DHA also upregulated p53, CASP3, and cleaved-CASP3 and downregulated BCL2L1, MMP9, KDR, p-KDR, STAT1 and p-STAT1 in GC cell lines. In conclusion, DHA could suppress the tumorigenesis and invasion of GC by regulating STAT1/KDR/MMP9 and p53/BCL2L1/CASP3/7 pathways. Our findings might provide a novel approach for the treatment of GC.

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.

Sesquiterpenes and their derivatives-natural anticancer compounds: An update

Sesquiterpenes belong to the largest group of plant secondary metabolites, which consist of three isoprene building units. These compounds are widely distributed in various angiosperms, a few gymnosperms and bryophytes. Sesquiterpenes and their allied derivatives are bio-synthesized in various plant parts including leaves, fruits and roots. These plant-based metabolites are predominantly identified in the Asteraceae family, wherein up to 5000 complexes have been documented to date. Sesquiterpenes and their derivatives are characteristically associated with plant defence mechanisms owing to their antifungal, antibacterial and antiviral activities. Over the last two decades, these compounds have been reportedly demonstrated health promoting perspectives against a wide range of metabolic syndromes i.e. hyperglycemia, hyperlipidemia, cardiovascular complications, neural disorders, diabetes, and cancer. The high potential of sesquiterpenes and their derivatives against various cancers like breast, colon, bladder, pancreatic, prostate, cervical, brain, liver, blood, ovarium, bone, endometrial, oral, lung, eye, stomach and kidney are the object of this review. Predominantly, it recapitulates the literature elucidating sesquiterpenes and their derivatives while highlighting the mechanistic approaches associated with their potent anticancer activities such as modulating nuclear factor kappa (NF-kB) activity, inhibitory action against lipid peroxidation and retarding the production of reactive oxygen & nitrogen species (ROS&RNS).

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

Background

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

Methods

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

Results

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

Conclusion

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

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

Dihydroartemisinin (DHA) has been reported to possess anti-cancer activity against many cancers. However, the pharmacologic effect of DHA on HBV-positive hepatocellular carcinoma (HCC) remains unknown. Thus, the objective of the present study was to determine whether DHA could inhibit the proliferation of HepG2.2.15 cells and uncover the underlying mechanisms involved in the effect of DHA on HepG2.2.15 cells. We found that DHA effectively inhibited HepG2.2.15 HCC cell proliferation both in vivo and in vitro. DHA also reduced the migration and tumorigenicity capacity of HepG2.2.15 cells. Regarding the underlying mechanisms, results showed that DHA induced cellular senescence by up-regulating expression levels of proteins such as p-ATM, p-ATR, γ-H₂AX, P53, and P21 involved in DNA damage response. DHA also induced autophagy (green LC3 puncta gathered together and LC3II/LC3I ratio increased through AKT-mTOR pathway suppression). Results also revealed that DHA-induced autophagy was not linked to senescence or cell death. TPP1 (telomere shelterin) overexpression could not rescue DHA-induced anticancer activity (cell proliferation). Moreover, DHA down-regulated TPP1 expression. Gene knockdown of TPP1 caused similar phenotypes and mechanisms as DHA induced phenotypes and mechanisms in HepG2.2.15 cells. These results demonstrate that DHA might inhibit HepG2.2.15 cells proliferation through inducing cellular senescence and autophagy.

Artemisinin Protects Human Retinal Pigmented Epithelial Cells Against Hydrogen Peroxide-induced Oxidative Damage by Enhancing the Activation of AMP-active Protein Kinase

Dry age-related macular degeneration (AMD), a leading cause of blindness in aged population, is directly associated with oxidative stress induced damage of the retinal pigmented epithelial (RPE) cells. In the current study, we investigated the role of AMPK in the protective effect of artemisinin, an FDA approved anti-malarial Chinese herbal drug, on RPE cell line D407, against H₂O₂ induced oxidative stress. Our results showed that artemisinin promoted the survival of D407 cells from H₂O₂. Artemisinin reduced intracellular ROS generation and oxidative stress, decreased LDH release and the loss of mitochondrial membrane potential in D407 cells treated with H₂O₂. Western blotting showed that artemisinin concentration- and time-dependently stimulated the phosphorylation of AMP-activated protein kinase (AMPK) in D407 cells while AMPK inhibitor Compound C or knock-down of AMPK by si-RNA, inhibited the survival protective effect of artemisinin. More importantly, artemisinin produced a similar protective effect in primary cultured retinal pigment cells which was also blocked by inhibitors of AMPK. Taken together, these results suggested that artemisinin promotes survival of human retinal pigment cells against H₂O₂-induced cell death at least in part through enhancing the activation of AMPK. Therefore, artemisinin may be a beneficial therapeutic candidate for the treatment of age-related diseases, including retinal disorders like AMD.

Dihydroartemisinin regulates the immune system by promotion of CD8+ T lymphocytes and suppression of B cell responses

Artemisia annua is an anti-fever herbal medicine first described in traditional Chinese medicine 1,000 years ago. Artemisinin, the extract of A. annua, and its derivatives (dihydroartemisinin (DHA), artemether, and artesunate) have been used for the treatment of malaria with substantial efficacy. Recently, DHA has also been tested for the treatment of lupus erythematosus, indicating that it may function to balance the immune response in immunocompromised individuals. In the present study, the regulatory effect of artemisinin on the murine immune system was systematically investigated in mice infected with two different protozoan parasites (Toxoplasma gondii and Plasmodium berghei). Our results revealed that the mouse spleen index significantly increased (spleen enlargement) in the healthy mice after DHA administration primarily due to the generation of an extra number of lymphocytes and CD8⁺ T lymphocytes in both the spleen and circulation. DHA could increase the proportion of T helper cells and CD8⁺ T cells, as well as decrease the number of splenic and circulatory B cells. Further, DHA could reduce the production of proinflammatory cytokines. Our study revealed that apart from their anti-parasitic activity, artemisinin and its derivatives can also actively modulate the immune system to directly benefit the host.

Effects of dihydroartemisinin on HSP70 expression in human prostate cancer PC-3 cells

We aimed to evaluate the effects of dihydroartemisinin (DHA) on heat-shock protein 70 (HSP70) expression in human prostate cancer PC-3 cells and to examine the molecular mechanism. The viability of PC-3 cells following treatment with 25, 50, 100 and 200 μmol/L DHA for 48 hr was detected by flow cytometry and MTT assay. The expression of HSP70 mRNA was detected by RT-qPCR. The expression levels and locations of HSP70, caspase-3 and apoptosis-inducing factor (AIF) were detected with immunofluorescence assay. With 100 μmol/L HSP70 inhibitor quercetin as positive control and dimethyl sulphoxide (DMSO) as solvent control, the protein expressions of HSP70, apoptotic protease activating factor-1 (Apaf-1) and AIF were detected by Western blot. DHA promoted PC-3 cell apoptosis dose-dependently. With increasing DHA dose, the expression of HSP70 mRNA significantly decreased (p < 0.05). DHA did not change the location of HSP70 or AIF. Compared with control and DMSO groups, the expression of HSP70 protein significantly decreased, and those of Apaf-1, caspase-3 and AIF significantly increased following treatment with DHA and quercetin for 48 hr. In conclusion, DHA inhibits the expression of HSP70 and induces the apoptosis of PC-3 cells. The results provide valuable experimental evidence for prostate cancer therapies using DHA.

Antimalarial Dihydroartemisinin triggers autophagy within HeLa cells of human cervical cancer through Bcl-2 phosphorylation at Ser70

BACKGROUND

As an effective antimalarial medicine, Dihydroartemisinin (DHA) has therapeutic potential on human cervical cancer. However, its working mechanism has not been elucidated.

PURPOSE

This study aimed to investigate the reversal effect of DHA on human cervical cancer HeLa cells, and explored its mechanism of action in vitro and in vivo.

STUDY DESIGN/METHODS

The effect and mechanism of DHA on HeLa cells was examined by using CCK-8 assay, flow cytometry, transmission electron microscopy, immunofluorescence, and Western blot analysis in human hepatocellular carcinoma cells.

RESULTS

In this study, it was confirmed that DHA had statistically equivalent anti-tumor efficiency in HeLa cells with a clinical chemotherapeutic agent of cisplatin. Meanwhile, DHA triggered autophagy, where LC3B-II expression was dose-dependently increased. Further, it was revealed that DHA promotes reactive oxygen species (ROS) generation, with DNA double-strand breaks (DSB) damage, as up-regulation of γH2AX protein and foci formation. Interestingly, we firstly demonstrated that DHA induced autophagy through promotion of the phosphorylation of Bcl-2 (Ser70), independent of the phosphorylated JNK1/2 (Thr183/Tyr185). Moreover, DHA-treated HeLa cells displayed an increase in the pro-autophagic protein Beclin-1 with downregulated the phospho-mTOR (Ser2448). Furthermore, upregulated pro-apoptotic protein Bak-1, but not Bax, suggesting Bak-1 is included in DHA-induced autophagy.

CONCLUSION

Therefore, DHA upregulates the phosphorylation of Bcl-2 (Ser70) and mTOR (Ser2448) and induces autophagic cell death in Hela cells. This study provided a mechanism to support DHA, an autophagy inducer, as a potential therapeutic agent for human cervical cancer.

Manilkara zapota (L.) P. Royen Leaf Water Extract Induces Apoptosis in Human Hepatocellular Carcinoma (HepG2) Cells via ERK1/2/Akt1/JNK1 Signaling Pathways

Manilkara zapota (L.) P. Royen, called sapodilla, or locally known as ciku, belongs to the family Sapotaceae. We found that Manilkara zapota leaf water extract has cytotoxic effect against human hepatocellular carcinoma (HepG2) cell line in our earlier study. Therefore, this study aimed to explore the anticancer properties of Manilkara zapota leaf water extract in HepG2 cells. We also aimed to unravel yet undiscovered mechanisms and identified several expressed genes whose functions in cytotoxicity activity of Manilkara zapota leaf water extract in HepG2 cells have not been well-studied. The apoptosis and intracellular reactive oxygen species (ROS) activities were analyzed using Annexin V-propidium iodide staining and dichlorodihydrofluorescein diacetate, respectively, by NovoCyte Flow Cytometer. Bax and Bcl-2 expression were assessed using Enzyme-Linked Immunosorbent Assay. The associated molecular pathways were evaluated by quantitative real-time PCR. Overall analyses revealed that Manilkara zapota leaf water extract can increase percentage of early apoptotic cells, induce the formation of ROS, upregulate c-Jun N-terminal kinase 1 (JNK1) and inducible nitric oxide synthase (iNOS), and reduce Akt1 and vascular endothelial growth factor A (VEGFA) transcriptional activities. Our data suggest that Manilkara zapota leaf water extract can suppress the growth of HepG2 cells via modulation of ERK1/2/Akt1/JNK1 transcriptional expression.

An Intrinsic Mitochondrial Pathway Is Required for Phytic Acid-Chitosan-Iron Oxide Nanocomposite (Phy-CS-MNP) to Induce G₀/G₁ Cell Cycle Arrest and Apoptosis in the Human Colorectal Cancer (HT-29) Cell Line

Magnetic iron oxide nanoparticles are among the most useful metal nanoparticles in biomedical applications. A previous study had confirmed that phytic acid-chitosan-iron oxide nanocomposite (Phy-CS-MNP) exhibited antiproliferative activity towards human colorectal cancer (HT-29) cells. Hence, in this work, we explored the in vitro cytotoxicity activity and mechanistic action of Phy-CS-MNP nanocomposite in modulating gene and protein expression profiles in HT-29 cell lines. Cell cycle arrest and apoptosis were evaluated by NovoCyte Flow Cytometer. The mRNA changes (cyclin-dependent kinase 4 (Cdk4), vascular endothelial growth factor A (VEGFA), c-Jun N-terminal kinase 1 (JNK1), inducible nitric oxide synthase (iNOS), and matrix metallopeptidase 9 (MMP9)) and protein expression (nuclear factor-kappa B (NF-κB) and cytochrome c) were assessed by quantitative real-time polymerase chain reaction (PCR) and western blotting, respectively. The data from our study demonstrated that treatment with Phy-CS-MNP nanocomposite triggered apoptosis and G₀/G₁ cell cycle arrest. The transcriptional activity of JNK1 and iNOS was upregulated after treatment with 90 μg/mL Phy-CS-MNP nanocomposite. Our results suggested that Phy-CS-MNP nanocomposite induced apoptosis and cell cycle arrest via an intrinsic mitochondrial pathway through modulation of Bax and Bcl-2 and the release of cytochrome c from the mitochondria into the cytosol.

Nanostructured Dihydroartemisinin Plus Epirubicin Liposomes Enhance Treatment Efficacy of Breast Cancer by Inducing Autophagy and Apoptosis

The heterogeneity of breast cancer and the development of drug resistance are the relapse reasons of disease after chemotherapy. To address this issue, a combined therapeutic strategy was developed by building the nanostructured dihydroartemisinin plus epirubicin liposomes. Investigations were performed on human breast cancer cells in vitro and xenografts in nude mice. The results indicated that dihydroartemisinin could significantly enhance the efficacy of epirubicin in killing different breast cancer cells in vitro and in vivo. We found that the combined use of dihydroartemisinin with epirubicin could efficiently inhibit the activity of Bcl-2, facilitate release of Beclin 1, and further activate Bax. Besides, Bax activated apoptosis which led to the type I programmed death of breast cancer cells while Beclin 1 initiated the excessive autophagy that resulted in the type II programmed death of breast cancer cells. In addition, the nanostructured dihydroartemisinin plus epirubicin liposomes prolonged circulation of drugs, and were beneficial for simultaneously delivering drugs into breast cancer tissues. Hence, the nanostructured dihydroartemisinin plus epirubicin liposomes could provide a new therapeutic strategy for treatment of breast cancer.

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.

L-A03, a dihydroartemisinin derivative, promotes apoptotic cell death of human breast cancer MCF-7 cells by targeting c-Jun N-terminal kinase

L-A03 is a dihydroartemisinin derivative and exerts distinct anti-tumor activity in vitro. Previous studies showed that induction of autophagy and deficiency in nitric oxide (NO) generation contributed to apoptotic cell death in L-A03-treated MCF-7 cells. However, the detailed mechanism is still unclear. In this study, the role of mitogen-activated protein kinases (MAPKs) in this apoptotic process was investigated. L-A03 (7.5-30 μM) selectively inhibited the activation of c-Jun N-terminal protein kinase (JNK) with no significant effect on extracellular signal related kinase (ERK) and p38. In addition, the possible mechanism of interaction between JNK and L-A03 was also investigated by molecular docking. In the presence of SP600125, a specific JNK inhibitor, induction of autophagy and apoptosis with L-A03 at 15 μM were elevated, but NO generation was attenuated, indicating that JNK inactivation is essential for apoptotic cell death. Interestingly, autophagy induction and NO generation did not affect the activation of JNK, demonstrating that JNK is upstream to autophagy and NO. Taken together, L-A03-induced JNK inactivation enhances autophagic and apoptotic cell death, but represses the generation of NO. This study provides a new insight on the mechanism of L-A03-induced cell death by targeting JNK.

Repurposing the anti-malarial drug dihydroartemisinin suppresses metastasis of non-small-cell lung cancer via inhibiting NF-κB/GLUT1 axis

Non-small-cell lung cancer (NSCLC) is an aggressive malignancy and long-term survival remains unsatisfactory for patients with metastatic and recurrent disease. Repurposing the anti-malarial drug dihydroartemisinin (DHA) has been proved to possess potent antitumor effect on various cancers. However, the effects of DHA in preventing the invasion of NSCLC cells have not been studied. In the present study, we determined the inhibitory effects of DHA on invasion and migration and the possible mechanisms involved using A549 and H1975 cells. DHA inhibited in vitro migration and invasion of NSCLC cells even in low concentration with little cytotoxicity. Additionally, low concentration DHA also inhibited Warburg effect in NSCLC cells. Mechanically, DHA negatively regulates NF-κB signaling to inhibit the GLUT1 translocation. Blocking the NF-κB signaling largely abolishes the inhibitory effects of DHA on the translocation of GLUT1 to the plasma membrane and the Warburg effect. Furthermore, GLUT1 knockdown significantly decreased the inhibition of invasion, and migration by DHA. Our results suggested that DHA can inhibit metastasis of NSCLC by targeting glucose metabolism via inhibiting NF-κB signaling pathway and DHA may deserve further investigation in NSCLC treatment.

FPHPB inhibits gastric tumor cell proliferation by inducing G2-M cell cycle arrest

Gastric cancer is a common cancer in the world with high morbidity and mortality. Here, we report that FPHPB (4-(4-(2-fluoropyridin-3-yl)phenyl)-N-(4-hydroxyphenyl)), a derivative of CMPD-1/MK2a Inhibitor, had anti-tumor activities by inhibiting gastric tumor SNU-16 and SGC7901 cells. FPHPB dose-dependently inhibited cell proliferation, induced cell apoptosis and arrested SNU-16 and SGC7901 cells in G2-M cell cycle checkpoint. Upon treatment with FPHPB, apoptotic proteins cleaved PARP and cleaved caspase-3 were remarkably increased, and G2-M regulatory molecules, the phosphorylation of Cdc2 and Chk2, were significantly accentuated. Collectively, FPHPB has anti-tumor activities and may be a potential candidate for treating gastric cancers.

Dihydroartemisinin induced caspase-dependent apoptosis through inhibiting the specificity protein 1 pathway in hepatocellular carcinoma SK-Hep-1 cells

AIMS

Dihydroartemisinin (DHA) is a semi-synthetic derivative of artemisinin, well known for a safe and effective first-line antimalarial agent. This study investigated whether and how DHA induces apoptosis focusing on the specificity protein 1 (Sp1) pathway in hepatocellular carcinoma (HCC) SK-Hep-1 cells.

MAIN METHODS

The cell viability was evaluated by MTT assay. Cell cycle analysis was performed after PI staining by flow cytometry system. Apoptosis was confirmed by DAPI staining and by detecting cytoplasmic histone-associated-DNA-fragments using a cell death detection ELISAPLUS kit. The expression of proteins involved in apoptosis was evaluated by Western blot. The nuclear localization of Sp1 was evaluated by immunofluorescence assay.

KEY FINDINGS

DHA exerted potent cytotoxicity against HCC SK-Hep-1 cells compared with normal hepatocyte AML12 cells. The sub-G1 DNA content and apoptosis index were increased by DHA, which was accompanied by nuclei condensation and fragmentation. DHA activated caspase 3, caspase 8, and caspase 9 and cleaved poly (ADP-ribose) polymerase (PARP). DHA-induced apoptotic cell death, activation of caspases and cleavage of PARP were dramatically inhibited by pan caspase inhibitor Z-VAD-FMK. DHA down-regulated protein expression and nuclear localization of Sp1, which in turn decreased Sp1 downstream target protein, X-linked inhibitor of apoptosis. Decreased Sp1 protein expression by DHA was restored by proteasome inhibitor MG132. DHA led to a down-regulation of phospho-ERK, -p38 and -JNK without affecting their total forms.

SIGNIFICANCE

These results demonstrate that DHA induces caspase-dependent apoptosis in HCC SK-Hep-1 cells by proteasome-dependent degradation of Sp1, which is involved in mitogen-activate protein kinase pathway.

Dihydroartemisinin increases apoptosis of colon cancer cells through targeting Janus kinase 2/signal transducer and activator of transcription 3 signaling

As a derivative of artemisinin, dihydroartemisinin is effective in the treatment of malaria. Dihydroartemisinin has been identified to possess inhibitory effects in numerous types of animal model with tumors, indicating that it has an antineoplastic effect. The aim of the present study was to analyze the potential anticancer effects of dihydroartemisinin, particularly its effect on apoptosis of colon cancer cells. In the present study, it was identified that dihydroartemisinin inhibited cell viability, promoted cell apoptosis, increased B-cell lymphoma-2-associated X-protein expression, increased caspase-3/9 activities, decreased poly(ADP-ribose) polymerase levels, decreased phosphorylation of extracellular-signal-regulated kinase, and increased phosphorylation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase in colon cancer cells. Conversely, the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) was suppressed by dihydroartemisinin in colon cancer cells. These results demonstrate that the potential anticancer effects of dihydroartemisinin may increase apoptosis of colon cancer cells through targeting JAK2/STAT3 signaling.

Dihydroartemisinin Exerts Anti-Tumor Activity by Inducing Mitochondrion and Endoplasmic Reticulum Apoptosis and Autophagic Cell Death in Human Glioblastoma Cells

Glioblastoma (GBM) is the most advanced and aggressive form of gliomas. Dihydroartemisinin (DHA) has been shown to exhibit anti-tumor activity in various cancer cells. However, the effect and molecular mechanisms underlying its anti-tumor activity in human GBM cells remain to be elucidated. Our results proved that DHA treatment significantly reduced cell viability in a dose- and time-dependent manner by CCK-8 assay. Further investigation identified that the cell viability was rescued by pretreatment either with Z-VAD-FMK, 3-methyladenine (3-MA) or in combination. Moreover, DHA induced apoptosis of GBM cells through mitochondrial membrane depolarization, release of cytochrome c and activation of caspases-9. Enhanced expression of GRP78, CHOP and eIF2α and activation of caspase 12 were additionally confirmed that endoplasmic reticulum (ER) stress pathway of apoptosis was involved in the cytotoxicity of DHA. DHA-treated GBM cells exhibited the morphological and biochemical changes typical of autophagy. Co-treatment with chloroquine (CQ) significantly induced the above effects. Furthermore, ER stress and mitochondrial dysfunction were involved in the DHA-induced autophagy. Further study revealed that accumulation of reactive oxygen species (ROS) was attributed to the DHA induction of apoptosis and autophagy. The illustration of these molecular mechanisms will present a novel insight for the treatment of human GBM.