Artesunate inhibits angiogenesis and downregulates vascular endothelial growth factor expression in chronic myeloid leukemia K562 cells

Searching for the Holy Grail - Highly Potent Bridged Endoperoxides for Targeted Cancer Therapy

The International Agency for Research on Cancer (IARC) recently estimated the global cancer burden in 2050. The statistics are startling, with a 77% hike and 35 million new cancer cases per year. The present discoveries have recommended plant-derived bridged endoperoxides or artemisinin-based semisynthetic analogues as safe, well-tolerated and powerful substitutes that could be effectively utilized as a warhead to fight against global enemies like cancer. In addition, artemisinin-based drug repositioning crucially can reduce overriding drug development expenditures and establish accessibility of approved drugs with low risk to patients. Hence, the present review article provides a comprehensive account of the recent chemical and synthetic advancement of diverse cytotoxic artemisinin derivatives such as C(10)-O, C, N, S linked artemisinin analogues, artemisinin-derived metal complexes, artemisinin-derived hybrids/conjugates with other pharmaceutically active substances, and artemisinin-derived dimers, trimers and tetramers perceived during the last three decades (1997-2024). Moreover, the current preclinical and clinical anticancer application prospects of artemisinin derivatives with other defined drugs and their utilization in combination therapy and also nanoformulation approaches for targeted drug delivery have been discussed.

Antitumour effects of artesunate via cell cycle checkpoint controls in human oesophageal squamous carcinoma cells

Artesunate (ART), an effective antimalarial semisynthetic derivative of artemisinin, exhibits antitumour properties, but the mechanism(s) involved remain elusive. In this study, we investigated the antitumour effects of ART on human oesophageal squamous cell carcinoma (ESCC) cell lines. Treatment of ESCC cell lines with ART resulted in the production of excessive reactive oxygen species (ROS) that induced DNA damage, reduced cell proliferation and inhibited clonogenicity via G1-S cell cycle arrest and/or apoptosis in vitro. The administration of ART to nude mice with ESCC cell xenografts inhibited tumour formation in vivo. However, the cytotoxicity of ART strongly differed among the ESCC cell lines tested. Transcriptomic profiling revealed that although the expression of large numbers of genes in ESCC cell lines was affected by ART treatment, these genes could be functionally clustered into pathways involved in regulating cell cycle progression, DNA metabolism and apoptosis. We revealed that p53 and Cdk4/6-p16-Rb cell cycle checkpoint controls were critical determinants required for mediating ART cytotoxicity in ESCC cell lines. Specifically, KYSE30 cells with p53Mut/p16Mut were the most sensitive to ART, KYSE150 and KYSE180 cells with p53Mut/p16Nor exhibited intermediate responses to ART, and Eca109 cells with p53Nor/p16Nor exhibited the most resistance to ATR. Consistently, perturbation of p53 expression using RNA interference (RNAi) and/or Cdk4/6 activity using the inhibitor palbociclib altered ART cytotoxicity in KYSE30 cells. Given that the p53 and Cdk4/6-cyclin D1-p16-Rb genes are commonly mutated in ESCC, our results potentially shed new light on neoadjuvant chemotherapy strategies for ESCC.

Overcoming Chemotherapy Resistance in Metastatic Cancer: A Comprehensive Review

The management of metastatic cancer is complicated by chemotherapy resistance. This manuscript provides a comprehensive academic review of strategies to overcome chemotherapy resistance in metastatic cancer. The manuscript presents background information on chemotherapy resistance in metastatic cancer cells, highlighting its clinical significance and the current challenges associated with using chemotherapy to treat metastatic cancer. The manuscript delves into the molecular mechanisms underlying chemotherapy resistance in subsequent sections. It discusses the genetic alterations, mutations, and epigenetic modifications that contribute to the development of resistance. Additionally, the role of altered drug metabolism and efflux mechanisms, as well as the activation of survival pathways and evasion of cell death, are explored in detail. The strategies to overcome chemotherapy resistance are thoroughly examined, covering various approaches that have shown promise. These include combination therapy approaches, targeted therapies, immunotherapeutic strategies, and the repurposing of existing drugs. Each strategy is discussed in terms of its rationale and potential effectiveness. Strategies for early detection and monitoring of chemotherapy drug resistance, rational drug design vis-a-vis personalized medicine approaches, the role of predictive biomarkers in guiding treatment decisions, and the importance of lifestyle modifications and supportive therapies in improving treatment outcomes are discussed. Lastly, the manuscript outlines the clinical implications of the discussed strategies. It provides insights into ongoing clinical trials and emerging therapies that address chemotherapy resistance in metastatic cancer cells. The manuscript also explores the challenges and opportunities in translating laboratory findings into clinical practice and identifies potential future directions and novel therapeutic avenues. This comprehensive review provides a detailed analysis of strategies to overcome chemotherapy resistance in metastatic cancer. It emphasizes the importance of understanding the molecular mechanisms underlying resistance and presents a range of approaches for addressing this critical issue in treating metastatic cancer.

Artesunate mitigates choroidal neovascularization and scar formation

Angiogenesis, although required during eye development, has a causative effect in many ocular diseases. Aberrant neovascularization contributes to the progression of neovascular age-related macular degeneration (nAMD), a vision-threaten disease in aging Americans. Since increased amounts of vascular endothelial growth factor (VEGF) drives neovascularization during the pathogenesis of nAMD the standard of care are anti-VEGF therapies attempt to disrupt this vicious cycle. These current anti-VEGF therapies try to maintain vascular homeostasis while abating aberrant neovascularization but regrettably don't prevent fibrosis or scar formation. In addition, some patients demonstrate an incomplete response to anti-VEGF therapy as demonstrated by progressive vision loss. Here, we show choroidal endothelial cells (ChEC) incubated with artesunate demonstrated decreased migration and inflammatory and fibrotic factor expression, which corresponded with decreased sprouting in a choroid/retinal pigment epithelium (RPE) explant sprouting angiogenesis assay. To assess the efficacy of artesunate to curtail neovascularization in vivo, we utilized laser photocoagulation-induced rupture of the Bruch's membrane to induce choroidal neovascularization (CNV). Artesunate significantly inhibited CNV and the accompanying fibrotic scar, perhaps due in part to its ability to inhibit mononuclear phagocyte (MP) recruitment. Thus, artesunate shows promise in inhibiting both CNV and fibrosis.

Repurposing approved non-oncology drugs for cancer therapy: a comprehensive review of mechanisms, efficacy, and clinical prospects

Cancer poses a significant global health challenge, with predictions of increasing prevalence in the coming years due to limited prevention, late diagnosis, and inadequate success with current therapies. In addition, the high cost of new anti-cancer drugs creates barriers in meeting the medical needs of cancer patients, especially in developing countries. The lengthy and costly process of developing novel drugs further hinders drug discovery and clinical implementation. Therefore, there has been a growing interest in repurposing approved drugs for other diseases to address the urgent need for effective cancer treatments. The aim of this comprehensive review is to provide an overview of the potential of approved non-oncology drugs as therapeutic options for cancer treatment. These drugs come from various chemotherapeutic classes, including antimalarials, antibiotics, antivirals, anti-inflammatory drugs, and antifungals, and have demonstrated significant antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties. A systematic review of the literature was conducted to identify relevant studies on the repurposing of approved non-oncology drugs for cancer therapy. Various electronic databases, such as PubMed, Scopus, and Google Scholar, were searched using appropriate keywords. Studies focusing on the therapeutic potential, mechanisms of action, efficacy, and clinical prospects of repurposed drugs in cancer treatment were included in the analysis. The review highlights the promising outcomes of repurposing approved non-oncology drugs for cancer therapy. Drugs belonging to different therapeutic classes have demonstrated notable antitumor effects, including inhibiting cell proliferation, promoting apoptosis, modulating the immune response, and suppressing metastasis. These findings suggest the potential of these repurposed drugs as effective therapeutic approaches in cancer treatment. Repurposing approved non-oncology drugs provides a promising strategy for addressing the urgent need for effective and accessible cancer treatments. The diverse classes of repurposed drugs, with their demonstrated antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties, offer new avenues for cancer therapy. Further research and clinical trials are warranted to explore the full potential of these repurposed drugs and optimize their use in treating various cancer types. Repurposing approved drugs can significantly expedite the process of identifying effective treatments and improve patient outcomes in a cost-effective manner.

Nano-Drug Delivery Systems Entrapping Natural Bioactive Compounds for Cancer: Recent Progress and Future Challenges

Cancer is a prominent cause of mortality globally, and it becomes fatal and incurable if it is delayed in diagnosis. Chemotherapy is a type of treatment that is used to eliminate, diminish, or restrict tumor progression. Chemotherapeutic medicines are available in various formulations. Some tumors require just one type of chemotherapy medication, while others may require a combination of surgery and/or radiotherapy. Treatments might last from a few minutes to many hours to several days. Each medication has potential adverse effects associated with it. Researchers have recently become interested in the use of natural bioactive compounds in anticancer therapy. Some phytochemicals have effects on cellular processes and signaling pathways with potential antitumor properties. Beneficial anticancer effects of phytochemicals were observed in both in vivo and in vitro investigations. Encapsulating natural bioactive compounds in different drug delivery methods may improve their anticancer efficacy. Greater in vivo stability and bioavailability, as well as a reduction in undesirable effects and an enhancement in target-specific activity, will increase the effectiveness of bioactive compounds. This review work focuses on a novel drug delivery system that entraps natural bioactive substances. It also provides an idea of the bioavailability of phytochemicals, challenges and limitations of standard cancer therapy. It also encompasses recent patents on nanoparticle formulations containing a natural anti-cancer molecule.

Combination of artesunate and WNT974 induces KRAS protein degradation by upregulating E3 ligase ANACP2 and β-TrCP in the ubiquitin–proteasome pathway

Background

KRAS mutation is one of the dominant gene mutations in colorectal cancer (CRC). Up to present, targeting KRAS for CRC treatment remains a clinical challenge. WNT974 (LGK974) is a porcupine inhibitor that interferes Wnt signaling pathway. Artesunate (ART) is a water-soluble semi-synthetic derivative of artemisinin.

Methods

The synergistic effect of ART and WNT974 combination in reducing CRC cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RT-PCR was utilized for the mRNA levels of KRAS, CUL7, ANAPC2, UBE2M, RNF123, SYVN1, or β-TrCP. Western blot assay was utilized for the protein levels of NRAS, HRAS, KRAS, ANAPC2, β-TrCP, GSK-3β, p-Akt (Ser473), t-Akt, p-PI3K (Tyr458), t-PI3K, p-mTOR (Ser2448), t-mTOR. Xenograft mouse model assay was performed for the anti-CRC effect of combination of ART and WNT974 in vivo. IHC assay was utilized for the levels of KRAS, β-TrCP, GSK-3β or ANAPC2 in tumor tissues.

Results

Our study shows that the combination of WNT974 and ART exhibits synergistic effect in reducing CRC growth. The combination treatment significantly reduces KRAS protein level and activity in CRC cells. Interestingly, the combination treatment increases E3 ligases ANAPC2 expression. Our data show that overexpression of ANAPC2 significantly reduces KRAS protein levels, which is reversed by MG132. Knockdown of ANAPC2 in CRC abolishes the combination treatment-reduce KRAS expression. Besides, the treatment also increases the expressions of GSK-3β and E3 ligase β-TrCP that is known to degrade GSK-3β-phosphorylated KRAS protein. Knockdown of β-TrCP- and inhibition of GSK-3β abolish the combination treatment-induce KRAS ubiquitination and reduction in expression. Last but not least, combination treatment suppresses PI3K/Akt/m-TOR signaling pathway.

Conclusions

Our data clearly show that the combination treatment significantly enhances KRAS protein degradation via the ubiquitination ubiquitin–proteasome pathway, which is also demonstrated in xenograft mouse model. The study provides strong scientific evidence for the development of the combination of WNT974 and ART as KRAS-targeting therapeutics for CRC treatment.

Repurposing Artemisinin and its Derivatives as Anticancer Drugs: A Chance or Challenge?

Cancer has become a global health problem, accounting for one out of six deaths. Despite the recent advances in cancer therapy, there is still an ever-growing need for readily accessible new therapies. The process of drug discovery and development is arduous and takes many years, and while it is ongoing, the time for the current lead compounds to reach clinical trial phase is very long. Drug repurposing has recently gained significant attention as it expedites the process of discovering new entities for anticancer therapy. One such potential candidate is the antimalarial drug, artemisinin that has shown anticancer activities in vitro and in vivo. In this review, major molecular and cellular mechanisms underlying the anticancer effect of artemisinin and its derivatives are summarised. Furthermore, major mechanisms of action and some key signaling pathways of this group of compounds have been reviewed to explore potential targets that contribute to the proliferation and metastasis of tumor cells. Despite its established profile in malaria treatment, pharmacokinetic properties, anticancer potency, and current formulations that hinder the clinical translation of artemisinin as an anticancer agent, have been discussed. Finally, potential solutions or new strategies are identified to overcome the bottlenecks in repurposing artemisinin-type compounds as anticancer drugs.

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

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

Pharmacological Targeting of Ferroptosis in Cancer Treatment

Ferroptosis is a non-apoptotic mode of Regulated Cell Death (RCD) driven by excessive accumulation of toxic lipid peroxides and iron overload. Ferroptosis could be triggered by inhibiting the antioxidant defense system and accumulating iron-dependent Reactive Oxygen Species (ROS) that react with polyunsaturated fatty acids in abundance. Emerging evidence over the past few years has revealed that ferroptosis is of great potential in inhibiting growth and metastasis and overcoming tumor cell resistance. Thus, targeting this form of cell death could be perceived as a potentially burgeoning approach in cancer treatment. This review briefly presents the underlying mechanisms of ferroptosis and further aims to discuss various types of existing drugs and natural compounds that could be potentially repurposed for targeting ferroptosis in tumor cells. This, in turn, will provide critical perspectives on future studies concerning ferroptosis-based cancer therapy.

Artesunate Suppresses Choroidal Melanoma Vasculogenic Mimicry Formation and Angiogenesis via the Wnt/CaMKII Signaling Axis

Angiogenesis and vasculogenic mimicry (VM) are considered to be the main processes to ensure tumor blood supply during the proliferation and metastasis of choroidal melanoma (CM). The traditional antimalarial drug artesunate (ART) has some potential anti-CM effects; however, the underlying mechanisms remain unclarified. Recent studies have shown that the Wnt5a/calmodulin-dependent kinase II (CaMKII) signaling pathway has a close correlation with angiogenesis and VM formation. This study demonstrated that ART eliminated VM formation by inhibiting the aforementioned signaling pathway in CM cells. The microvessel sprouting of the mouse aortic rings and the microvessel density of chicken chorioallantoic membrane (CAM) decreased significantly after ART treatment. VM formation assay and periodic acid schiff (PAS) staining revealed that ART inhibited VM formation in CM. Moreover, ART downregulated the expression levels of the angiogenesis-related proteins vascular endothelial growth factor receptor (VEGFR) 2, platelet-derived growth factor receptor (PDGFR) and vascular endothelial growth factor (VEGF) A, and VM-related proteins ephrin type-A receptor (EphA) 2 and vascular endothelial (VE)-cadherin. The expression of hypoxia-inducible factor (HIF)-1α, Wnt5a, and phosphorylated CaMKII was also downregulated after ART treatment. In addition, we further demonstrated that ART inhibited the proliferation, migration, and invasion of OCM-1 and C918 cells. Collectively, our results suggested that ART inhibited angiogenesis and VM formation of choroidal melanoma likely by regulating the Wnt5a/CaMKII signaling pathway. These findings further supported the feasibility of ART for cancer therapy.

Suppression of USP7 induces BCR-ABL degradation and chronic myelogenous leukemia cell apoptosis

Chronic myelogenous leukemia (CML) is a clonal malignancy of hematopoietic stem cells featured with the fusion protein kinase BCR-ABL. To elicit the mechanism underlying BCR-ABL stability, we perform a screen against a panel of deubiquitinating enzymes (DUBs) and find that the ubiquitin-specific protease 7 (USP7) drastically stabilizes the BCR-ABL fusion protein. Further studies show that USP7 interacts with BCR-ABL and blocks its polyubiquitination and degradation. Moreover, USP7 knockdown triggers BCR-ABL degradation and suppresses its downstream signaling transduction. In line with this finding, genetic or chemical inhibition of USP7 leads to BCR-ABL protein degradation, suppresses BCR/ABL signaling, and induces CML cell apoptosis. Furthermore, we find the antimalarial artesunate (ART) significantly inhibits USP7/BCR-ABL interaction, thereby promoting BCR-ABL degradation and inducing CML cell death. This study thus identifies USP7 as a putative Dub of BCR-ABL and provides a rationale in targeting USP7/BCR-ABL for the treatment of CML.

Ferroptosis: A Novel Mechanism of Artemisinin and its Derivatives in Cancer Therapy

BACKGROUND

Artemisinin is a sesquiterpene lactone compound with a special peroxide bridge that is tightly linked to the cytotoxicity involved in fighting malaria and cancer. Artemisinin and its derivatives (ARTs) are considered to be potential anticancer drugs that promote cancer cell apoptosis, induce cell cycle arrest and autophagy, inhibit cancer cell invasion and migration. Additionally, ARTs significantly increase intracellular Reactive Oxygen Species (ROS) in cancer cells, which result in ferroptosis, a new form of cell death, depending on the ferritin concentration. Ferroptosis is regarded as a cancer suppressor and as well as considered a new mechanism for cancer therapy.

METHODS

The anticancer activities of ARTs and reference molecules were compared by literature search and analysis. The latest research progress on ferroptosis was described, with a special focus on the molecular mechanism of artemisinin-induced ferroptosis.

RESULTS

Artemisinin derivatives, artemisinin-derived dimers, hybrids and artemisinin-transferrin conjugates, could significantly improve anticancer activity, and their IC50 values are lower than those of reference molecules such as doxorubicin and paclitaxel. The biological activities of linkers in dimers and hybrids are important in the drug design processes. ARTs induce ferroptosis mainly by triggering intracellular ROS production, promoting the lysosomal degradation of ferritin and regulating the System Xc-/Gpx4 axis. Interestingly, ARTs also stimulate the feedback inhibition pathway.

CONCLUSION

Artemisinin and its derivatives could be used in the future as cancer therapies with broader applications due to their induction of ferroptosis. Meanwhile, more attention should be paid to the development of novel artemisinin-related drugs based on the mechanism of artemisinininduced ferroptosis.

Artemisinin-type drugs for the treatment of hematological malignancies

Qinghaosu, known as artemisinin (ARS), has been for over two millennia, one of the most common herbs prescribed in traditional Chinese medicine (TCM). ARS was developed as an antimalarial drug and currently belongs to the established standard treatments of malaria as a combination therapy worldwide. In addition to the antimalarial bioactivity of ARS, anticancer activities have been shown both in vitro and in vivo. Like other natural products, ARS acts in a multi-specific manner also against hematological malignancies. The chemical structure of ARS is a sesquiterpene lactone, which contains an endoperoxide bridge essential for activity. The main mechanism of action of ARS and its derivatives (artesunate, dihydroartemisinin, artemether) toward leukemia, multiple myeloma, and lymphoma cells comprises oxidative stress response, inhibition of proliferation, induction of various types of cell death as apoptosis, autophagy, ferroptosis, inhibition of angiogenesis, and signal transducers, as NF-κB, MYC, amongst others. Therefore, new pharmaceutically active compounds, dimers, trimers, and hybrid molecules, could enhance the existing therapeutic alternatives in combating hematologic malignancies. Owing to the high potency and good tolerance without side effects of ARS-type drugs, combination therapies with standard chemotherapies could be applied in the future after further clinical trials in hematological malignancies.

Dihydroartemisinin inhibits the expression of von Willebrand factor by downregulation of transcription factor ERG in endothelial cells

Dihydroartemisinin (DHA), a semi‐synthetic derivative of artemisinin, has effective antitumor and anti‐inflammatory actions. von Willebrand factor (vWF), a large multifunctional glycoprotein, has a prominent function in hemostasis and is a key factor in thrombus formation. In addition, vWF has been regarded as a prospective biomarker for the diagnosis of endothelial dysfunction. In our experiment, we observed that 25 μM DHA specifically downregulated the expression of vWF mRNA and protein in human umbilical vein endothelial cells (HUVECs). Further investigations demonstrated that this DHA‐decreased vWF expression was mediated by the transcription factor ERG and not GATA3. Luciferase activity assay confirmed that DHA regulated the ERG binding with the −56 ETS‐binding motif on the human vWF promoter. Thus, the −56 ETS motif on the vWF promoter region regulates the expression of vWF gene which is induced by DHA. Taken together, we proved that DHA decreased the vWF transcription through the downregulation of ERG in HUVECs. As vWF plays a key role in vascular homeostasis, our findings suggest a new role of DHA in vascular diseases.

Secondary metabolites (essential oils) from sand-dune plants induce cytotoxic effects in cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

Despite advances in modern therapeutic strategies, cancer remains the second leading cause of death worldwide. Therefore, there is a constant need to develop more efficient anticancer targeting strategies. The anticancer therapeutic proprieties of medicinal plants and their bioactive compounds have been reported for several years, making natural extracts and/or compounds derived from these a promising source of novel anticancer agents. Sand dune plants are subjected to severe environmental stresses, leading to the development of adaptations, including the production of secondary metabolites with a wide range of bioactivities, such as: anti-inflammatory, analgesic, antiseptic, hypoglycaemic, hypotensive, antinociceptive, antioxidant and anticancer.

AIM OF THE STUDY

The anticancer potential of sand dune plants remains under-investigated, so this research describes the characterisation of the composition of bioactive EOs from sand-dune plants of Peniche (Portugal), and assessment of their activity in vitro and potential mechanism of action.

MATERIALS AND METHODS

EOs were extracted from six sand-dune species of plants from Peniche sand dunes: Crithmum maritimum L., Seseli tortuosum L., Artemisia campestris subsp. maritima (DC.) Arcang., Juniperus phoenicea var. turbinata (Guss.) Parl., Otanthus maritimus (L.) Hoffmanns. & Link, and Eryngium maritimum L.. EOs composition was fully characterised chemically using Gas Chromatography-Mass Spectrometry (GC-MS). The assessment of anticancer activity and mechanism of action was performed in vitro using breast and colorectal cancer 2D and 3D spheroid cell line models, through cell proliferation assay, western blotting analysis, and cell cycle analysis.

RESULTS

EOs from the majority of the species tested (S. tortuosum, A. campestris subsp. maritima, O. maritimus, and E. maritimum) were mainly composed by hydrocarbon compounds (sequisterpenes and monoterpenes), showing antiproliferative activity in both 2D and 3D models. EO extracted from S. tortuosum and O. maritimus were identified as having the lowest IC₅₀ values for both cell lines when compared with the other species tested. Furthermore, this antiproliferative activity was associated with increased p21 expression and induction of apoptosis.

CONCLUSIONS

The present study suggests that EOs extracted from S. tortuosum and O. maritimus present promising cytotoxic properties. Further evaluation of the extracts and their key components as potential anticancer agents should therefore be explored.

Artemisinin and its derivatives: a promising cancer therapy

The world is experiencing a cancer epidemic and an increase in the prevalence of the disease. Cancer remains a major killer, accounting for more than half a million deaths annually. There is a wide range of natural products that have the potential to treat this disease. One of these products is artemisinin; a natural product from Artemisia plant. The Nobel Prize for Medicine was awarded in 2015 for the discovery of artemisinin in recognition of the drug's efficacy. Artemisinin produces highly reactive free radicals by the breakdown of two oxygen atoms that kill cancerous cells. These cells sequester iron and accumulate as much as 1000 times in comparison with normal cells. Generally, chemotherapy is toxic to both cancerous cells and normal cells, while no significant cytotoxicity from artemisinin to normal cells has been found in more than 4000 case studies, which makes it far different than conventional chemotherapy. The pleiotropic response of artemisinin in cancer cells is responsible for growth inhibition by multiple ways including inhibition of angiogenesis, apoptosis, cell cycle arrest, disruption of cell migration, and modulation of nuclear receptor responsiveness. It is very encouraging that artemisinin and its derivatives are anticipated to be a novel class of broad-spectrum antitumor agents based on efficacy and safety. This review aims to highlight these achievements and propose potential strategies to develop artemisinin and its derivatives as a new class of cancer therapeutic agents.

Artemisinin and its derivatives: a potential treatment for leukemia

Artemisinin (ART) and its derivatives are one of the most important classes of antimalarial agents, originally derived from a Chinese medicinal plant called Artemisia annua L. Beyond their outstanding antimalarial and antischistosomal activities, ART and its derivatives also possess both in-vitro and in-vivo activities against various types of cancer. Their anticancer effects range from initiation of apoptotic cell death to inhibition of cancer proliferation, metastasis and angiogenesis, and even modulation of the cell signal transduction pathway. This review provides a comprehensive update on ART and its derivatives, their mechanisms of action, and their synergistic effects with other chemicals in targeting leukemia cells. Combined with limited evidence of drug resistance and low toxicity profile, we conclude that ART and its derivatives, including dimers, trimers, and hybrids, might be a potential therapeutic alternative to current chemotherapies in combating leukemia, although more studies are necessary before they can be applied clinically.

pH-Responsive Artesunate Polymer Prodrugs with Enhanced Ablation Effect on Rodent Xenograft Colon Cancer

Purpose

In this study, pH-sensitive poly(2-ethyl-2-oxazoline)-poly(lactic acid)-poly(β-amino ester) (PEOz-PLA-PBAE) triblock copolymers were synthesized and were conjugated with an antimalaria drug artesunate (ART), for inhibition of a colon cancer xenograft model.

Methods

The as-prepared polymer prodrugs are tended to self-assemble into polymeric micelles in aqueous milieu, with PEOz segment as hydrophilic shell and PLA-PBAE segment as hydrophobic core.

Results

The pH sensitivity of the as-prepared copolymers was confirmed by acid-base titration with pKb values around 6.5. The drug-conjugated polymer micelles showed high stability for at least 96 h in PBS and 37°C, respectively. The as-prepared copolymer prodrugs showed high drug loading content, with 9.57%±1.24% of drug loading for PEOz-PLA-PBAE-ART4. The conjugated ART could be released in a sustained and pH-dependent manner, with 92% of released drug at pH 6.0 and 57% of drug released at pH 7.4, respectively. In addition, in vitro experiments showed higher inhibitory effect of the prodrugs on rodent CT-26 cells than that of free ART. Animal studies also demonstrated the enhanced inhibitory efficacy of PEOz-PLA-PBAE-ART2 micelles on the growth of rodent xenograft tumor.

Conclusion

The pH-responsive artesunate polymer prodrugs are promising candidates for colon cancer adjuvant therapy.

Research Progress on Artemisinin and Its Derivatives against Hematological Malignancies

Although current therapeutic methods against hematological malignancies are effective in the early stage, they usually lose their effectiveness because of the development of drug resistances. Seeking new drugs with significant therapeutic effects is one of the current research hotspots. Artemisinin, an extract from the plant Artemisia annua Linne, and its derivatives have excellent antimalarial effects in clinical applications as well as excellent safety. Recent studies have documented that artemisinin and its derivatives (ARTs) also have significant effects against multiple types of tumours, including hematological malignancies. This review focuses on the latest research achievements of ARTs in the treatment of hematological malignancies as well as its mechanisms and future applications. The mechanisms of ARTs against different types of hematological malignancies mainly include cell cycle arrest, induction autophagy and apoptosis, inhibition of angiogenesis, production of reactive oxygen species, and induction of differentiation. Additionally, the review also summarizes the anticancer effects of ARTs in many drug-resistant hematological malignancies and its synergistic effects with other drugs.

Potential applications of artemisinins in ocular diseases

Artemisinin, also named qinghaosu, is a family of sesquiterpene trioxane lactone originally derived from the sweet wormwood plant (Artemisia annua), which is a traditional Chinese herb that has been universally used as anti-malarial agents for many years. Evidence has accumulated during the past few years which demonstrated the protective effects of artemisinin and its derivatives (artemisinins) in several other diseases beyond malaria, including cancers, autoimmune disorders, inflammatory diseases, viral and other parasite-related infections. Recently, this long-considered anti-malarial agent has been proved to possess anti-oxidant, anti-inflammatory, anti-apoptotic and anti-excitotoxic properties, which make it a potential treatment option for the ocular environment. In this review, we first described the overview of artemisinins, highlighting the activity of artemisinins to other diseases beyond malaria and the mechanisms of these actions. We then emphasized the main points of published results of using artemisinins in targeting ocular disorders, including uveitis, retinoblastoma, retinal neurodegenerative diseases and ocular neovascularization. To conclude, we believe that artemisinins could also be used as a promising therapeutic drug for ocular diseases, especially retinal vascular diseases in the near future.

Anticancer Activity of Natural Compounds from Plant and Marine Environment

This paper describes the substances of plant and marine origin that have anticancer properties. The chemical structure of the molecules of these substances, their properties, mechanisms of action, their structure⁻activity relationships, along with their anticancer properties and their potential as chemotherapeutic drugs are discussed in this paper. This paper presents natural substances from plants, animals, and their aquatic environments. These substances include the vinca alkaloids, mistletoe plant extracts, podophyllotoxin derivatives, taxanes, camptothecin, combretastatin, and others including geniposide, colchicine, artesunate, homoharringtonine, salvicine, ellipticine, roscovitine, maytanasin, tapsigargin, and bruceantin. Compounds (psammaplin, didemnin, dolastin, ecteinascidin, and halichondrin) isolated from the marine plants and animals such as microalgae, cyanobacteria, heterotrophic bacteria, invertebrates (e.g., sponges, tunicates, and soft corals) as well as certain other substances that have been tested on cells and experimental animals and used in human chemotherapy.

Dihydroartemisinin enhances VEGFR1 expression through up-regulation of ETS-1 transcription factor

Angiogenesis is required for tumor growth. Dihydroartemisinin (DHA), a the effective anti-malarial derivative of artemisinin, demonstrated potent anti-angiogenic activities that closely related to the regulation of vascular endothelial growth factor (VEGF) signaling cascade. VEGF receptor 1 (VEGFR1), a receptor in endothelial cells (ECs), coordinately regulate angiogenic activity triggered by ligand-receptor binding. Here we aimed to explore the effects of DHA on VEGFR1 expression in ECs. We found that DHA significantly increases VEGFR1 expression in human umbilical vein endothelial cells (HUVECs). In addition, DHA significantly upregulates the level of V-Ets Avian Erythroblastosis Virus E26 Oncogene Homolog 1 (ETS-1), a transcriptional factor which binds to the human VEGFR1 promoter. ChIP assay showed that DHA increases ETS-1 binding to the -52 ETS motif on the VEGFR1 promoter. Knockdown of ETS-1 by RNA interference abolished DHA-induced increase of VEGFR1 expression. Taken together, we demonstrated that DHA elevates VEGFR1 expression via up-regulation of ETS-1 transcription in HUVECs.

Nucleolin mediated pro-angiogenic role of Hydroxysafflor Yellow A in ischaemic cardiac dysfunction: Post-transcriptional regulation of VEGF-A and MMP-9

Hydroxysafflor Yellow A (HSYA), a most representative ingredient of Carthamus tinctorius L., had long been used in treating ischaemic cardiovascular diseases in China and exhibited prominently anticoagulant and pro-angiogenic activities, but the underlying mechanisms remained largely unknown. This study aimed to further elucidate the pro-angiogenic effect and mechanism of HSYA on ischaemic cardiac dysfunction. A C57 mouse model of acute myocardial infarction (AMI) was firstly established, and 25 mg/kg HSYA was intraperitoneally injected immediately after operation and given once, respectively, each morning and evening for 2 weeks. It was found that HSYA significantly improved ischaemia-induced cardiac haemodynamics, enhanced the survival rate, alleviated the myocardial injury and increased the expressions of CD31, vascular endothelial growth factor-A (VEGF-A) and nucleolin in the ischaemic myocardium. In addition, HSYA promoted the migration and tube formation of human umbilical vein endothelial cells (HUVECs), enhanced the expressions of nucleolin, VEGF-A and matrix metalloproteinase-9 (MMP-9) in a dose- and time-dependent manner. However, down-regulation of nucleolin expression sharply abrogated the effect mentioned above of HSYA. Further protein-RNA coimmunoprecipitation and immunoprecipitation-RT-PCR assay showed that nucleolin binded to VEGF-A and MMP-9 mRNA and overexpression of nucleolin up-regulated the mRNA expressions of VEGF-A and MMP-9 in the HUVECs through enhancing the stability of VEGF-A and MMP-9 mRNA. Furthermore, HSYA increased the mRNA expressions of VEGF-A and MMP-9 in the extract of antinucleolin antibody-precipitated protein from the heart of AMI mice. Our data revealed that nucleolin mediated the pro-angiogenic effect of HSYA through post-transcriptional regulation of VEGF-A and MMP-9 expression, which contributed to the protective effect of HSYA on ischaemic cardiac dysfunction.

A phase I study of intravenous artesunate in patients with advanced solid tumor malignancies

PURPOSE

The artemisinin class of anti-malarial drugs has shown significant anti-cancer activity in pre-clinical models. Proposed anti-cancer mechanisms include DNA damage, inhibition of angiogenesis, TRAIL-mediated apoptosis, and inhibition of signaling pathways. We performed a phase I study to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of intravenous artesunate (IV AS).

METHODS

Patients were enrolled in an accelerated titration dose escalation study with planned dose levels of 8, 12, 18, 25, 34 and 45 mg/kg given on days 1 and 8 of a 21-day cycle. Toxicities were assessed using the NCI CTCAE (ver. 4.0), and response was assessed using RECIST criteria (version 1.1). Pharmacokinetic (PK) studies were performed during cycle 1.

RESULTS

A total of 19 pts were enrolled, 18 of whom were evaluable for toxicity and 15 were evaluable for efficacy. DLTs were seen at dosages of 12 (1 of 6 patients), 18 (1 of 6) and 25 mg/kg (2 of 2), and were neutropenic fever (Gr 4), hypersensitivity reaction (Gr 3), liver function test abnormalities (Gr 3/4) along with neutropenic fever, and nausea/vomiting (Gr 3) despite supportive care. The MTD was determined to be 18 mg/kg. No responses were observed, while four patients had stable disease, including three with prolonged stable disease for 8, 10, and 11 cycles, for a disease control rate of 27%. PK parameters of AS and its active metabolite, dihydroartemisinin (DHA), correlated with dose.

CONCLUSION

The MTD of intravenous artesunate is 18 mg/kg on this schedule. Treatment was well tolerated. Modest clinical activity was seen in this pre-treated population. CLINICALTRIALS.

GOV IDENTIFIER

NCT02353026.

VEGFR2-targeted fusion antibody improved NK cell-mediated immunosurveillance against K562 cells

MHC class I polypeptide-related sequence A (MICA), which is normally expressed on cancer cells, activates NK cells via NK group 2-member D pathway. However, some cancer cells escape NK-mediated immune surveillance by shedding membrane MICA causing immune suppression. To address this issue, we designed an antibody-MICA fusion targeting tumor-specific antigen (vascular endothelial growth factor receptor 2, VEGFR2) based on our patented antibody (mAb04) against VEGFR2. In vitro results demonstrate that the fusion antibody retains both the antineoplastic and the immunomodulatory activity of mAb04. Further, we revealed that it enhanced NK-mediated immunosurveillance against K562 cells through increasing degranulation and cytokine production of NK cells. The overall data suggest our new fusion protein provides a promising approach for cancer-targeted immunotherapy and has prospects for potential application of chronic myeloid leukemia.

Artesunate inhibits proliferation and invasion of mouse hemangioendothelioma cells in vitro and of tumor growth in vivo

Artesunate has been demonstrated to be a novel potential antitumor agent in numerous studies. However, its efficacy in infantile hemangioma is unknown. The aim of the present study was to investigate the role of artesunate in the control of vascular tumor biological behavior and molecular mechanism using mouse hemangioendothelioma endothelial (EOMA) cells and a nude mouse model. Cell viability, apoptosis and invasion were determined by an MTT assay, flow cytometric analysis and Transwell invasion assay, respectively. Reverse transcription-quantitative polymerase chain reaction and western blotting were utilized to examine the expression of genes and proteins. Inoculated EOMA cells were injected into the subcutaneous tissues of nude mice to observe the effect of artesunate therapy on the vascular tumor, an effect that was similar to that of pingyangmycin (PYM). It was identified that artesunate treatment (0-600 µg/ml) inhibited cell growth in a time- and dose-dependent manner. Artesunate at 300 µg/ml significantly reduced the proliferation and invasion of EOMA cells, and significantly decreased the expression of vascular endothelial growth factor (VEGF)-A, VEGFR-1, VEGFR-2 and hypoxia inducible factor-1α over time; caspase-3 was simultaneously upregulated in vitro. Artesunate significantly inhibited tumor growth, and the curative effect was similar to that observed with PYM in vivo. It was concluded that artesunate could effectively inhibit the growth of vascular tumors, and thus could be a novel drug candidate for the treatment of infantile hemangioma.

Molecular Cloning and Characterization of Ribosomal Protein RPS9 in Echinococcus granulosus

Ribosomal protein S9 (RPS9) is an essential functional gene that participates in DNA repair and developmental regulations. A sequence homolog of RPS9 has been found to be upregulated in the protoscoleces (PSCs) of Echinococcus granulosus treated with artemisinin. However, E. granulosus RPS9 (EgRPS9) has not been identified before. In the present study, the 657-base pair (bp) cDNA encoding EgRPS9 was cloned. Amino acid sequence analysis showed that EgRPS9 was similar to the RSP9 proteins from Schistosoma japonicum (SjRPS9, 86%) and Schistosoma mansoni (SmRPS9, 79%). Phylogenetic tree analysis showed that EgRPS9, SmRPS9, and SjRPS9 were clustered together. We detected the EgRPS9 gene and protein expression in PSCs exposed to artesunate (AS) which displayed a dose-dependent reduction in PSC viability for 24 hr. The results showed that the EgRPS9 ratio of the 10-μM AS-treated ( P < 0.01) and 40-μM AS-treated ( P < 0.05) groups were increased from that of the control group. In addition, the level of reactive oxygen species (ROS) in the AS-treated groups increased in a dose-dependent manner compared to the level in the control group. In conclusion, the expression of EgRPS9 could be induced by ROS and might participate in the oxidative damage-based anti-parasite mechanism of AS treatment.

Drug repurposing in cancer

Cancer is a major health issue worldwide, and the global burden of cancer is expected to increase in the coming years. Whereas the limited success with current therapies has driven huge investments into drug development, the average number of FDA approvals per year has declined since the 1990s. This unmet need for more effective anti-cancer drugs has sparked a growing interest for drug repurposing, i.e. using drugs already approved for other indications to treat cancer. As such, data both from pre-clinical experiments, clinical trials and observational studies have demonstrated anti-tumor efficacy for compounds within a wide range of drug classes other than cancer. Whereas some of them induce cancer cell death or suppress various aspects of cancer cell behavior in established tumors, others may prevent cancer development. Here, we provide an overview of promising candidates for drug repurposing in cancer, as well as studies describing the biological mechanisms underlying their anti-neoplastic effects.

Effective Medicinal Plant in Cancer Treatment, Part 2: Review Study

Cancer is the second cause of death after cardiovascular diseases. With due attention to rapid progress in the phytochemical study of plants, they are becoming popular because of their anticancer effects. The aim of this study was to investigate the effective medicinal plants in the treatment of cancer and study their mechanism of action. In order to gather information the keywords “traditional medicine,” “plant compounds,” “medicinal plant,” “medicinal herb,” “toxicity,” “anticancer effect,” “cell line,” and “treatment” were searched in international databases such as ScienceDirect, PubMed, and Scopus and national databases such as Magiran, Sid, and Iranmedex, and a total of 228 articles were collected. In this phase, 49 nonrelevant articles were excluded. Enhancement P53 protein expression, reducing the expression of proteins P27, P21, NFκB expression and induction of apoptosis, inhibition of the PI3K/Akt pathway, and reduction of the level of acid phosphatase and lipid peroxidation are the most effective mechanisms of herbal plants that can inhibit cell cycle and proliferation. Common treatments such as radiotherapy and chemotherapy can cause some complications. According to results of this study, herbal extracts have antioxidant compounds that can induce apoptosis and inhibit cell proliferation by the investigated mechanisms.

Dihydroartemisinin transiently activates the JNK/SAPK signaling pathway in endothelial cells

Artemisinin and its derivatives are well-known anti-malaria drugs and in the early stages of research for cancer treatment. Dihydroartemisinin (DHA), a more water-soluble derivative of artemisinin, has demonstrated strong anti-angiogenic activity. The purpose of the present study was to investigate the underlying molecular mechanisms of the effect of DHA on angiogenesis. Human umbilical vein endothelial cells (HUVECs) treated with DHA were examined for apoptosis and activation of the c-Jun N-terminal kinase (JNK) signaling pathway, one of the major mitogen-activated protein kinase cascades. It was observed that 20 µM DHA induces transient activation of JNK in HUVECs. DHA also elevates the expression of cyclooxygenase-2 and matrix metalloproteinase-13, which is abolished by treatment with the JNK inhibitor SP600125. Although DHA persistently increases inhibitor of κB-α protein and thus inhibits nuclear factor-κB signaling, it does not affect apoptosis or caspase 3/9 activities in HUVECs. The present study provides key information for understanding the effects of DHA on endothelial cells, which is required for investigating its potential for clinic application as a chemotherapeutic agent.

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.

Repurposing the anti-malarial drug artesunate as a novel therapeutic agent for metastatic renal cell carcinoma due to its attenuation of tumor growth, metastasis, and angiogenesis

Despite advances in the development of molecularly targeted therapies, metastatic renal cell carcinoma (RCC) is still incurable. Artesunate (ART), a well-known anti-malarial drug with low toxicity, exhibits highly selective anti-tumor actions against various tumors through generation of cytotoxic carbon-centered free radical in the presence of free iron. However, the therapeutic efficacy of ART against metastatic RCC has not yet been fully elucidated. In the analysis on a dataset from The Cancer Genome Atlas (TCGA) (n = 469) and a tissue microarray set from Samsung Medical Center (n = 119) from a cohort of patients with clear cell RCC (ccRCC), up-regulation of transferrin receptor 1 (TfR1), which is a well-known predictive marker for ART, was correlated with the presence of distant metastasis and an unfavorable prognosis. Moreover, ART exerted potent selective cytotoxicity against human RCC cell lines (Caki-1, 786-O, and SN12C-GFP-SRLu2) and sensitized these cells to sorafenib in vitro, and the extent of ART cytotoxicity correlated with TfR1 expression. ART-mediated growth inhibition of human RCC cell lines was shown to result from the induction of cell cycle arrest at the G2/M phase and oncosis-like cell death. Furthermore, ART inhibited cell clonogenicity and invasion of human RCC cells and anti-angiogenic effects in vitro in a dose-dependent manner. Consistent with these in vitro data, anti-tumor, anti-metastatic and anti-angiogenic effects of ART were also validated in human 786-O xenografts. Taken together, ART is a promising novel candidate for treating human RCC, either alone or in combination with other therapies.

Small Molecular-Sized Artesunate Attenuates Ocular Neovascularization via VEGFR2, PKCα, and PDGFR Targets

Ocular neovascularization (NV) is the primary cause of blindness in many ocular diseases. Large molecular weight anti- vascular endothelial growth factor (VEGF) protein drugs, such as Avastin and Lucentis, have saved the vision of millions. However, approximately 20-30% of patients respond poorly to anti-VEGF treatment. We found that artesunate (ART), a small molecular derivative of artemisinin, had a significant inhibitory effect on ocular NV by downregulating the expression of VEGFR2, PKCα, and PDGFR. ART significantly inhibited retinal NV in rabbits and macular edema in monkeys with greater anterior chamber penetrability and more durable efficacy than Avastin. Our pilot study showed that intravitreal injection of 80 μg ART significantly inhibited iris and corneal NV in a severe retinal detachment case. Our results suggest that ART might be a potential persistent small-molecule drug to manage ocular NV via multi-targets.

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.

Artemisinin Represses Telomerase Subunits and Induces Apoptosis in HPV-39 Infected Human Cervical Cancer Cells

Artemisinin, a plant-derived antimalarial drug with relatively low toxicity on normal cells in humans, has selective anticancer activities in various types of cancers, both in vitro and in vivo. In the present study, we have investigated the anticancer effects of artemisinin in human cervical cancer cells, with special emphasis on its role in inducing apoptosis and repressing cell proliferation by inhibiting the telomerase subunits, ERα which is essential for maintenance of the cervix, and downstream components like VEGF, which is known to activate angiogenesis. Effects of artemisinin on apoptosis of ME-180 cells were measured by flow cytometry, DAPI, and annexin V staining. Expression of genes and proteins related to cell proliferation and apoptosis was quantified both at the transcriptional and translational levels by semi-quantitative RT-PCR and western blot analysis, respectively. Our findings demonstrated that artemisinin significantly downregulated the expression of ERα and its downstream component, VEGF. Antiproliferative activity was also supported by decreased telomerase activity and reduced expression of hTR and hTERT subunits. Additionally, artemisinin reduced the expression of the HPV-39 viral E6 and E7 components. Artemisinin-induced apoptosis was confirmed by FACS, nuclear chromatin condensation, annexin V staining. Increased expression of p53 with concomitant decrease in expression of the p53 inhibitor Mdm2 further supported that artemisinin-induced apoptosis was p53-dependent. The results clearly indicate that artemisinin induces antiproliferative and proapoptotic effects in HPV-39-infected ME-180 cells, and warrants further trial as an effective anticancer drug.

A Systematic Review of Iran’s Medicinal Plants With Anticancer Effects

Increase in cases of various cancers has encouraged the researchers to discover novel, more effective drugs from plant sources. This study is a review of medicinal plants in Iran with already investigated anticancer effects on various cell lines. Thirty-six medicinal plants alongside their products with anticancer effects as well as the most important plant compounds responsible for the plants’ anticancer effect were introduced. Phenolic and alkaloid compounds were demonstrated to have anticancer effects on various cancers in most studies. The plants and their active compounds exerted anticancer effects by removing free radicals and antioxidant effects, cell cycle arrest, induction of apoptosis, and inhibition of angiogenesis. The investigated plants in Iran contain the compounds that are able to contribute effectively to fighting cancer cells. Therefore, the extract and active compounds of the medicinal plants introduced in this review article could open a way to conduct clinical trials on cancer and greatly help researchers and pharmacists develop new anticancer drugs.

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.

Engineering of a disulfide loop instead of a Zn binding loop restores the anti-proliferative, anti-angiogenic and anti-tumor activities of the N-terminal fragment of endostatin: Mechanistic and therapeutic insights

Although considerable effort has been devoted to understanding the molecular mechanism of endostatin's anti-cancer activity, the role of its Zn bound N-terminal loop has not been completely clarified. To investigate whether Zn binding or the N-terminal loop is involved in the anti-cancer properties of endostatin, we compared the structure and biological activity of a native Zn binding endostatin peptide (ES-Zn) with three variants: a Zn free variant (ES), a variant containing both a Zn binding site and a disulfide bond (ES-SSZn), and a variant including a disulfide loop but incapable of Zn binding (ES-SS). Spectroscopic studies indicated that ES-Zn and ES-SS consist of random coil and β structures, whereas ES-SSZn and ES fold into random coils. Theoretical analysis proposed that ES-Zn and ES-SS have a similar binding site to αVβ3 integrin. The anti-proliferative activity of endostatin was retained by all peptides except ES, and the in vitro anti-angiogenic property was preserved in ES-Zn and ES-SS. Remarkably, breast tumor growth and CD31 activity were inhibited more effectively by ES-SS than by ES-Zn. Therefore, a correlation exists between the N-terminal loop and anti-cancer properties of endostatin fragment and a disulfide loop may be more promising than a Zn binding loop for inhibiting tumor growth.

CUSP9* treatment protocol for recurrent glioblastoma: aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, ritonavir, sertraline augmenting continuous low dose temozolomide

CUSP9 treatment protocol for recurrent glioblastoma was published one year ago. We now present a slight modification, designated CUSP9*. CUSP9* drugs--aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, sertraline, ritonavir, are all widely approved by regulatory authorities, marketed for non-cancer indications. Each drug inhibits one or more important growth-enhancing pathways used by glioblastoma. By blocking survival paths, the aim is to render temozolomide, the current standard cytotoxic drug used in primary glioblastoma treatment, more effective. Although esthetically unpleasing to use so many drugs at once, the closely similar drugs of the original CUSP9 used together have been well-tolerated when given on a compassionate-use basis in the cases that have come to our attention so far. We expect similarly good tolerability for CUSP9*. The combined action of this suite of drugs blocks signaling at, or the activity of, AKT phosphorylation, aldehyde dehydrogenase, angiotensin converting enzyme, carbonic anhydrase -2,- 9, -12, cyclooxygenase-1 and -2, cathepsin B, Hedgehog, interleukin-6, 5-lipoxygenase, matrix metalloproteinase -2 and -9, mammalian target of rapamycin, neurokinin-1, p-gp efflux pump, thioredoxin reductase, tissue factor, 20 kDa translationally controlled tumor protein, and vascular endothelial growth factor. We believe that given the current prognosis after a glioblastoma has recurred, a trial of CUSP9* is warranted.

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.