Dihydroartemisinin Is Cytotoxic to Papillomavirus-Expressing Epithelial Cells In vitro and In vivo

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Perceived acceptability of self-administered topical therapy for cervical precancer treatment among women undergoing cervical cancer screening in Kenya

Purpose

Innovative strategies are urgently needed to meet the World Health Organization's 2030 target of treating 90% of women with precancerous cervical lesions, especially in countries most affected by cervical cancer. We assessed the acceptability of self-administered intravaginal therapies for treating cervical precancer in women undergoing cervical cancer screening and precancer treatment in Kenya.

Methods

We conducted a cross-sectional study among women aged 18 to 65 years undergoing cervical cancer screening or precancer treatment between January and October 2023 in Kisumu County, Kenya. Participants completed a questionnaire about their perceptions and perceived acceptability of self- or provider-administered topical therapies for cervical precancer treatment. Quantitative data were summarized using descriptive statistics.

Results

A total of 379 questionnaires were completed. The median age of participants was 35 years (IQR 25-62), 62% had a primary education or less, and 71% earned $5 or less daily. All participants had been screened for cervical cancer, and 191 (51%) had received precancer treatment, primarily thermal ablation. Ninety-eight percent of participants were willing to use a self-administered intravaginal therapy for cervical precancer, if available. The majority, 91%, believed their male partner would support their use. Given a choice, 63% preferred self-admiration at home compared to provider-administration of a topical therapy in the clinic, citing time and cost savings. In multivariate analysis, married women were more likely to expect partner support for self-administration than single women. Participants preferred a therapy used less frequently but for a longer duration, compared to daily use therapy with a shorter duration of use.

Conclusions

Self-administered intravaginal therapies for cervical precancer treatment are highly acceptable among women undergoing screening and precancer treatment in Kenya.

A phase I study of intra-anal artesunate (suppositories) to treat anal high-grade squamous intraepithelial lesions

BACKGROUND

Ablation or surgical excision is the typical treatment of anal high-grade squamous intraepithelial lesions (HSIL). Recurrences are common due to the persistence of underlying human papillomavirus (HPV) infection. Additional well-tolerated and effective non-surgical options for HPV-associated anal disease are needed.

METHODS

This 3+3 dose escalation Phase I clinical trial evaluated the safety and tolerability of artesunate suppositories in the treatment of patients with biopsy-proven HSIL.

RESULTS

The maximal tolerated dose was 400 mg, administered in 3 cycles. All adverse events associated with the use 200- and 400-mg artesunate suppositories were Grade 1. At the 600-mg dose, patients experienced clinically significant nausea.

CONCLUSION

Artesunate suppositories are a safe treatment option for anal HSIL.

Safety and efficacy of topical artesunate for the treatment of vulvar intraepithelial neoplasia 2/3

OBJECTIVE

To evaluate the safety, tolerability, and efficacy of topical artesunate ointment for treatment of biopsy-confirmed Human papillomavirus (HPV)-associated Vulvar intraepithelial neoplasia (VIN) 2/3.

METHODS

Participants were enrolled on a prospective, IRB-approved, dose-escalation phase I trial testing either 1, 2 or 3 treatment cycles (5 days), every other week, as applicable. Clinical assessments were completed prior to each dose cycle and included exam and review of adverse event (AE) diary cards. HPV testing and colposcopy was completed at 15 and 28 weeks. AEs were assessed according to CTCAE 4.0 criteria. Complete responders (CR) underwent biopsy of the treated site at the 28-weeks while partial (PR) and non (NR)-responders underwent surgical resection or biopsy and ablation.

RESULTS

Fifteen patients consented to and began treatment. Per-protocol assessments were completed in 100% at 15- and 80% at 28-weeks. All patients completed prescribed cycles with no grade 3 or 4 AEs. Vulvovaginal burning/ was the most common AE occurring in 93.3%. AEs were grade 2 in 23.7% and included vulvovaginal pruritus (n = 3), swelling (n = 3) and candidiasis (n = 2). The highest ORR was in the 3-cycle group (88.9% with 55.6% CR). HPV-16 was detected either alone (46.7%) or with other subtypes (33.3%) in 80% of lesions and 5 of 8 (62.5%) with CR had complete viral clearance.

CONCLUSIONS

Topical artesunate for treatment of high-grade VIN shows high tolerability, low toxicity and evidence for clinical response in this initial small series. The safety and observed responses support further study in a Phase II trial.

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.

Therapeutical Utilization and Repurposing of Artemisinin and Its Derivatives: A Narrative Review

Artemisinin (ART) and its derivatives have great therapeutical utility as antimalarials and can be repurposed for other indications, such as viral infections, autoimmune diseases, and cancer. This review presents a comprehensive overview of the therapeutic effects of ART-based drugs, beyond their antimalarial effects. This review also summarizes the information on their repurposing in other pathologies, with the hope that it will guide the future optimization of the use of ART-based drugs and of the treatment strategies for the listed diseases. By reviewing related literature, ART extraction and structure as well as the synthesis and structure of its derivatives are presented. Subsequently, the traditional roles of ART and its derivatives against malaria are reviewed, including antimalarial mechanism and occurrence of antimalarial resistance. Finally, the potential of ART and its derivatives to be repurposed for the treatment of other diseases are summarized. The great repurposing potential of ART and its derivatives may be useful for the control of emerging diseases with corresponding pathologies, and future research should be directed toward the synthesis of more effective derivatives or better combinations.

The antiviral effects of a MEK1/2 inhibitor promote tumor regression in a preclinical model of human papillomavirus infection-induced tumorigenesis

Human papillomaviruses (HPVs) are a significant public health concern due to their widespread transmission, morbidity, and oncogenic potential. Despite efficacious vaccines, millions of unvaccinated individuals and those with existing infections will develop HPV-related diseases for the next two decades and beyond. The continuing burden of HPV-related diseases is exacerbated by the lack of effective therapies or cures for infections, highlighting the need to identify and develop antivirals. The experimental murine papillomavirus type 1 (MmuPV1) model provides opportunities to study papillomavirus pathogenesis in cutaneous epithelium, the oral cavity, and the anogenital tract. However, to date the MmuPV1 infection model has not been used to demonstrate the effectiveness of potential antivirals. We previously reported that inhibitors of cellular MEK/ERK signaling suppress oncogenic HPV early gene expression in three-dimensional tissue cultures. Herein, we adapted the MmuPV1 infection model to determine whether MEK inhibitors have anti-papillomavirus properties in vivo. We demonstrate that oral delivery of a MEK1/2 inhibitor promotes papilloma regression in immunodeficient mice that otherwise would have developed persistent infections. Quantitative histological analyses reveal that inhibition of MEK/ERK signaling reduces E6/E7 mRNA, MmuPV1 DNA, and L1 protein expression within MmuPV1-induced lesions. These data suggest that MEK1/2 signaling is essential for both early and late MmuPV1 replication events supporting our previous findings with oncogenic HPVs. We also provide evidence that MEK inhibitors protect mice from developing secondary tumors. Thus, our data suggest that MEK inhibitors have potent antiviral and anti-tumor properties in a preclinical mouse model and merit further investigation as papillomavirus antiviral therapies.

Inhibition of Cellular MEK/ERK Signaling Suppresses Murine Papillomavirus Type 1 Replicative Activities and Promotes Tumor Regression

Human papillomaviruses (HPVs) are a significant public health concern due to their widespread transmission, morbidity, and oncogenic potential. Despite efficacious vaccines, millions of unvaccinated individuals and those with existing infections will develop HPV-related diseases for the next two decades. The continuing burden of HPV-related diseases is exacerbated by the lack of effective therapies or cures for most infections, highlighting the need to identify and develop antivirals. The experimental murine papillomavirus type 1 (MmuPV1) model provides opportunities to study papillomavirus pathogenesis in cutaneous epithelium, the oral cavity, and the anogenital tract. However, to date the MmuPV1 infection model has not been used to demonstrate the effectiveness of potential antivirals. We previously reported that inhibitors of cellular MEK/ERK signaling suppress oncogenic HPV early gene expression in vitro . Herein, we adapted the MmuPV1 infection model to determine whether MEK inhibitors have anti-papillomavirus properties in vivo . We demonstrate that oral delivery of a MEK1/2 inhibitor promotes papilloma regression in immunodeficient mice that otherwise would have developed persistent infections. Quantitative histological analyses revealed that inhibition of MEK/ERK signaling reduces E6/E7 mRNAs, MmuPV1 DNA, and L1 protein expression within MmuPV1-induced lesions. These data suggest that MEK1/2 signaling is essential for both early and late MmuPV1 replication events supporting our previous findings with oncogenic HPVs. We also provide evidence that MEK inhibitors protect mice from developing secondary tumors. Thus, our data suggest that MEK inhibitors have potent anti-viral and anti-tumor properties in a preclinical mouse model and merit further investigation as papillomavirus antiviral therapies.

Significance Statement

Persistent human papillomavirus (HPV) infections cause significant morbidity and oncogenic HPV infections can progress to anogenital and oropharyngeal cancers. Despite the availability of effective prophylactic HPV vaccines, millions of unvaccinated individuals, and those currently infected will develop HPV-related diseases over the next two decades and beyond. Thus, it remains critical to identify effective antivirals against papillomaviruses. Using a mouse papillomavirus model of HPV infection, this study reveals that cellular MEK1/2 signaling supports viral tumorigenesis. The MEK1/2 inhibitor, trametinib, demonstrates potent antiviral activities and promotes tumor regression. This work provides insight into the conserved regulation of papillomavirus gene expression by MEK1/2 signaling and reveals this cellular pathway as a promising therapeutic target for the treatment of papillomavirus diseases.

Natural biomolecules and derivatives as anticancer immunomodulatory agents

Despite advancements in chemotherapy, the issue of resistance and non-responsiveness to many chemotherapeutic drugs that are currently in clinical use still remains. Recently, cancer immunotherapy has gathered attention as a novel treatment against select cancers. Immunomodulation is also emerging as an effective strategy to improve efficacy. Natural phytochemicals, with known anticancer properties, been reported to mediate their effects by modulating both traditional cancer pathways and immunity. The mechanism of phytochemical mediated-immunomodulatory activity may be attributed to the remodeling of the tumor immunosuppressive microenvironment and the sensitization of the immune system. This allows for improved recognition and targeting of cancer cells by the immune system and synergy with chemotherapeutics. In this review, we will discuss several well-known plant-derived biomolecules and examine their potential as immunomodulators, and therefore, as novel immunotherapies for cancer treatment.

Lessons learned from the discovery and development of the sesquiterpene lactones in cancer therapy and prevention

INTRODUCTION

Sesquiterpene lactones (SLs) are one of the most diverse bioactive secondary metabolites found in plants and exhibit a broad range of therapeutic properties . SLs have been showing promising potential in cancer clinical trials, and the molecular mechanisms underlying their anticancer potential are being uncovered. Recent evidence also points to a potential utility of SLs in cancer prevention.

AREAS COVERED

This work evaluates SLs with promising anticancer potential based on cell, animal, and clinical models: Artemisinin, micheliolide, thapsigargin dehydrocostuslactone, arglabin, parthenolide, costunolide, deoxyelephantopin, alantolactone, isoalantolactone, atractylenolide 1, and xanthatin as well as their synthetic derivatives. We highlight actionable molecular targets and biological mechanisms underlying the anticancer therapeutic properties of SLs. This is complemented by a unique assessment of SL mechanisms of action that can be exploited in cancer prevention. We also provide insights into structure-activity and pharmacokinetic properties of SLs and their potential use in combination therapies.

EXPERT OPINION

We extract seven major lessons learned and present evidence-based solutions that can circumvent some scientific limitations or logistic impediments in SL anticancer research. SLs continue to be at the forefront of cancer drug discovery and are worth a joint interdisciplinary effort in order to leverage their potential in cancer therapy and prevention.

Enhancement of the cytotoxic effect of dihydroartemisinin in high-risk human papillomavirus-infected cells by aminolevulinic acid via the Bax/Bcl-2-caspase pathway

BACKGROUND

Traditional treatments for human papillomavirus-related cutaneous diseases include 5-aminolevulinic acid photodynamic therapy, cryotherapy, microwave ablation, and surgical resection. These treatment methods involvevarious adverse reactions; therefore, it remains necessary to explore new treatment methods. Dihydroartemisinin shows cytotoxic effects against several malignancies by producing reactive oxygen species, and heme environments reportedly enhance its activity. However, the underlying mechanismsare still unclear. Therefore, we investigated the mechanism of dihydroartemisininin inhuman papillomavirus-infected cells.

METHODS

HeLa cells were treated with dihydroartemisinin, 5-aminolevulinic acid, and succinylacetone. The cell viability, apoptosis, mitochondrial membrane potential, and reactive oxygen species levels were investigated, and via western blotting analysis and polymerase chain reaction, dihydroartemisinin activity-related pathways were also determined.

RESULTS

Dihydroartemisinin inhibited HeLa cell proliferation and promoted cell apoptosis via the Bax/Bcl-2-Caspase pathway in a concentration-dependent manner. The specific cytotoxicity toward HeLa cells was enhanced by the addition of 5-aminolevulinic acid, a clinically used heme-synthesis precursor, owing to an increase in heme levels. Conversely, following the addition of succinylacetone, a heme synthesis blocker, heme levels decreased. Furthermore, dihydroartemisinin significantly increased reactive oxygen species levels as intracellular heme synthesis increased. Moreover, photodynamic therapy following dihydroartemisinin and 5-aminolevulinic acid treatment further enhanced the cytotoxic effect of dihydroartemisinin on high-risk human papillomavirus-infected cells.

CONCLUSIONS

Dihydroartemisinin exerts acytotoxic effect on high-risk human papillomavirus-infected cells by modulating heme levels via the Bax/Bcl-2-Caspase pathway, and the dihydroartemisinin, 5-aminolevulinic acid, photodynamic therapy combination treatment significantly enhanced its cytotoxic effect on human papillomavirus-infected cells.

Efficacy of Topically Administered Dihydroartemisinin in Treating Papillomavirus-Induced Anogenital Dysplasia in Preclinical Mouse Models

The artemisinin family of compounds is cytopathic in certain cancer cell lines that are positive for human papillomaviruses (HPV) and can potentially drive the regression of dysplastic lesions. We evaluated the efficacy of topical dihydroartemisinin (DHA) on cervical dysplasia and anal dysplasia in two papillomavirus mouse models: K14E6/E7 transgenic mice, which express HPV16 oncogenes; and immunodeficient NOD/SCID gamma (NSG) mice infected with Mus musculus papillomavirus (MmuPV1). Mice started treatment with DHA at 25 weeks of age (K14E6/E7) or 20 weeks post infection (MmuPV1-infected), when the majority of mice are known to have papillomavirus-induced low- to high-grade dysplasia. Mice were treated with or without topical DHA at the cervix or anus and with or without topical treatment with the chemical carcinogen 7,12 dimethylbenz(a)anthracene (DMBA) at the anus of in transgenic mice to induce neoplastic progression. Mice were monitored for overt tumor growth, and tissue was harvested after 20 weeks of treatment and scored for severity of histological disease. For MmuPV1-infected mice, anogenital lavages were taken to monitor for viral clearance. Tissues were also evaluated for viral gene expression at the RNA and/or protein levels. Treatment with topical DHA did not reduce dysplasia in the anogenital tract in either papillomavirus-induced mouse model and did not prevent progression to anal cancer in the DMBA-treated K14E6/E7 mice.

Co-delivery of dihydroartemisinin and pyropheophorbide-iron elicits ferroptosis to potentiate cancer immunotherapy

Dihydroartemisinin (DHA) has shown cytotoxicity against various tumor cells in vitro in an iron-dependent manner, but its in vivo antitumor efficacy is compromised by its rapid degradation and clearance. Here we show the induction of ferroptosis by DHA in an immunogenic fashion and the maximization of in vivo antitumor efficacy of DHA by co-delivering a cholesterol derivative of DHA (Chol-DHA) and Pyropheophorbide-iron (Pyro-Fe) in ZnP@DHA/Pyro-Fe core-shell nanoparticles. ZnP@DHA/Pyro-Fe particles stabilize DHA against hydrolysis and prolong blood circulation of Chol-DHA and Pyro-Fe for their enhanced uptake in tumors. Co-delivery of an exogenous iron complex and DHA induces more ROS production and causes significant tumor inhibition in vivo. By increasing tumor immunogenicity, the combination of DHA and Pyro-Fe sensitizes non-immunogenic colorectal tumors to anti-PD-L1 checkpoint blockade immunotherapy. These findings suggest the potential of using nanotechnology to repurpose DHA and other drugs with excellent safety profiles for combination with immune checkpoint blockade to treat cancers.

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.

Cytotoxicity of an Innovative Pressurised Cyclic Solid-Liquid (PCSL) Extract from Artemisia annua

Therapeutic treatments with Artemisia annua have a long-established tradition in various diseases due to its antibacterial, antioxidant, antiviral, anti-malaria and anti-cancer effects. However, in relation to the latter, virtually all reports focused on toxic effects of A. annua extracts were obtained mostly through conventional maceration methods. In the present study, an innovative extraction procedure from A. annua, based on pressurised cyclic solid–liquid (PCSL) extraction, resulted in the production of a new phytocomplex with enhanced anti-cancer properties. This extraction procedure generated a pressure gradient due to compressions and following decompressions, allowing to directly perform the extraction without any maceration. The toxic effects of A. annua PCSL extract were tested on different cells, including three cancer cell lines. The results of this study clearly indicate that the exposure of human, murine and canine cancer cells to serial dilutions of PCSL extract resulted in higher toxicity and stronger propensity to induce apoptosis than that detected by subjecting the same cells to Artemisia extracts obtained through canonical extraction by maceration. Collected data suggest that PCSL extract of A. annua could be a promising and economic new therapeutic tool to treat human and animal tumours.

Ergosterol peroxide: an effect-directed detecting method from Anoectochilus elwesii and evaluation of anticancer activity

Ergosterol peroxide (EP) in Anoectochilus elwesii possesses antioxidant and anticancer properties, yet few studies have been focused on its mechanisms and directed detecting. By practicing HPTLC-DPPH coupled with UHPLC-ESI-TOF MS, EP was located and the cytotoxic activity of EP was performed by MTT method. The apoptosis studies were conducted on SGC-7901cells by AO/EB and Annex V/PI staining method, PI flow cytometric assay, reactive oxygen species detection and mitochondrial membrane potential assay. An effect-directed detecting method of HPTLC-DPPH/UHPLC/ESI-TOF-MS was developed for EP rapidly and precisely, providing an option for identifying oxidative compounds. EP exhibits high cytotoxic activity against SGC-7901 gastric cancer cells and the morphological apoptosis suggested that EP induced apoptosis and cell cycle arrest in G0/G1 phase. It could enhance the ROS level and cause a decrease in the mitochondrial membrane potential. Its antiproliferative mechanism is G0/G1 phase arrest and might be traced through ROS-mediated mitochondrial dysfunction pathways.

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

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

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

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

The Therapeutic Effects of Dihydroartemisinin on Cisplatin-Resistant Gastric Cancer Cells

BACKGROUND

Dihydroartemisinin (DHA) exhibited anti-tumor effect in a variety of cancer cells but its mechanism of action is unclear.

OBJECTIVE

To investigate the therapeutic effects of DHA on Cisplatin (DDP)-resistant gastric cancer cell strain SGC7901/DDP and the possible molecular mechanism.

METHODS

Cells were treated with DHA in dose- and time-dependent manners, after which their proliferation, apoptosis, invasion and migration abilities were evaluated. We further evaluated autophagy with mRFP-GFP-LC3 adenovirus transfection and transmission electron microscopy, and also detected the expression levels of proteins (related to autophagy and apoptosis) via western blot. Meanwhile, the influence of DHA on cisplatin resistance was detected through a sensitization test and the evaluation of P-gp expression levels.

RESULTS

DHA effectively inhibited the proliferation, invasion, and migration of SGC7901/DDP cells and induced cell apoptosis which was accompanied by caspase-8/9/3 activation. Furthermore, exposure of DHA resulted in a pronounced increase in autophagy proteins including Beclin-1 and LC3 II with PI3K/AKT/mTOR pathway inhibition. Additionally, enhancement of cisplatin sensitivity occurred in SGC7901/DDP cells treated with DHA, which was accompanied by P-gp downregulation.

CONCLUSION

DHA exerts an anti-cancer effect on SGC7901/DDP cells and the mechanisms possibly include enhancement of autophagy via PI3K/AKT/mTOR inhibition, inducement of apoptosis through caspase-dependent and mitochondrial pathway, and enhancement of cisplatin sensitivity through P-gp inhibition.

Dihydroartemisinin administration improves the effectiveness of 5-aminolevulinic acid-mediated photodynamic therapy for the treatment of high-risk human papillomavirus infection

AIMS AND BACKGROUND

High-risk human papillomavirus (HR-HPV) infection has been confirmed to be highly related to diseases such as Bowenoid papulosis, cervical cancer, and cervical intraepithelial neoplasia. 5-aminolevulinic acid-mediated PDT (ALA-PDT) has been used in a variety of HR-HPV infection-related diseases. Dihydroartemisinin (DHA) is one of artemisinin derivatives, and has inhibitory effects on a variety of cancer cells. For now, there is no published study focusing on the combination use of ALA-PDT with DHA to improve clinical efficacy of HR-HPV infection-related diseases. So in this study, we will examine the effectiveness of combined treatment of ALA-PDT and DHA for HR-HPV infection as well as its underlying mechanism.

METHODS

The human cervical cancer cell line HeLa (containing whole genome of HR-HPV18) was treated with ALA-PDT or/and DHA, and cell viability, long proliferation, ROS production and apoptosis were evaluated by CCK8, colony-forming assay, immunofluorescence and flow cytometry, respectively. The protein expression of NF-κB-HIF-1α-VEGF pathway and NRF2-HO-1 pathway was examined by western blot.

RESULTS

The results showed that DHA could enhance the effect of ALA-PDT on cell viability long proliferation, ROS production and apoptosis in HeLa cells. We also found that DHA inhibited NF-κB-HIF-1α-VEGF pathway which was activated by ALA-PDT. Besides, ALA-PDT combined with DHA activated NRF2-HO-1 pathway.

CONCLUSION

Although the NRF2 - NO-1 pathway as a resistance mechanism remains unresolved, DHA has the potential to enhance the effect of ALA-PDT for HPV infection-related diseases through inhibiting NF-κB - HIF-1α - VEGF pathway.

Artesunate Inhibits Growth of Sunitinib-Resistant Renal Cell Carcinoma Cells through Cell Cycle Arrest and Induction of Ferroptosis

Simple Summary

Renal cell carcinoma (RCC) is the most common kidney malignancy. Due to development of therapy resistance, efficacy of conventional drugs such as sunitinib is limited. Artesunate (ART), a drug originating from Traditional Chinese Medicine, has exhibited anti-tumor effects in several non-urologic tumors. ART inhibited growth, reduced metastatic properties, and curtailed metabolism in sunitinib-sensitive and sunitinib–resistant RCC cells. In three of four tested cell lines, ART’s growth inhibitory effects were accompanied by cell cycle arrest and modulation of cell cycle regulating proteins. In a fourth cell line, KTCTL-26, ART evoked ferroptosis, an iron-dependent cell death, and exhibited stronger anti-tumor effects than in the other cell lines. The regulatory protein, p53, was only detectable in the KTCTL-26 cells, possibly making p53 a predictive marker of cancer that may respond better to ART. ART, therefore, may hold promise as an additive therapy option for selected patients with advanced or therapy-resistant RCC.

Abstract

Although innovative therapeutic concepts have led to better treatment of advanced renal cell carcinoma (RCC), efficacy is still limited due to the tumor developing resistance to applied drugs. Artesunate (ART) has demonstrated anti-tumor effects in different tumor entities. This study was designed to investigate the impact of ART (1–100 µM) on the sunitinib-resistant RCC cell lines, Caki-1, 786-O, KTCTL26, and A-498. Therapy-sensitive (parental) and untreated cells served as controls. ART’s impact on tumor cell growth, proliferation, clonogenic growth, apoptosis, necrosis, ferroptosis, and metabolic activity was evaluated. Cell cycle distribution, the expression of cell cycle regulating proteins, p53, and the occurrence of reactive oxygen species (ROS) were investigated. ART significantly increased cytotoxicity and inhibited proliferation and clonogenic growth in both parental and sunitinib-resistant RCC cells. In Caki-1, 786-O, and A-498 cell lines growth inhibition was associated with G0/G1 phase arrest and distinct modulation of cell cycle regulating proteins. KTCTL-26 cells were mainly affected by ART through ROS generation, ferroptosis, and decreased metabolism. p53 exclusively appeared in the KTCTL-26 cells, indicating that p53 might be predictive for ART-dependent ferroptosis. Thus, ART may hold promise for treating selected patients with advanced and even therapy-resistant RCC.

Efficacy and mechanism of actions of natural antimicrobial drugs

Microbial infections have significantly increased over the last decades, and the mortality rates remain unacceptably high. The emergence of new resistance patterns and the spread of new viruses challenge the eradication of infectious diseases. The declining efficacy of antimicrobial drugs has become a global public health problem. Natural products derived from natural sources, such as plants, animals, and microorganisms, have significant efficacy for the treatment of infectious diseases accompanied by less adverse effects, synergy, and ability to overcome drug resistance. As the Chinese female scientist Youyou Tu received the Nobel Prize for the antimalarial drug artemisinin, antimicrobial drugs developed from Traditional Chinese Medicine are expected to receive increasing attention again. This review summarizes the antimicrobial agents derived from natural products approved for nearly 20 years and describes their efficacy and mode of action. The aim of this unit is to review the current status of antimicrobial drugs from natural products in order to increase the value of natural products as a source of novel drug candidates for infectious diseases.

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.

Artemisia annua, a Traditional Plant Brought to Light

Traditional remedies have been used for thousand years for the prevention and treatment of infectious diseases, particularly in developing countries. Of growing interest, the plant Artemisia annua, known for its malarial properties, has been studied for its numerous biological activities including metabolic, anti-tumor, anti-microbial and immunomodulatory properties. Artemisia annua is very rich in secondary metabolites such as monoterpenes, sesquiterpenes and phenolic compounds, of which the biological properties have been extensively studied. The purpose of this review is to gather and describe the data concerning the main chemical components produced by Artemisia annua and to describe the state of the art about the biological activities reported for this plant and its compounds beyond malaria.

RalB degradation by dihydroartemisinin induces autophagy and IFI16/caspase-1 inflammasome depression in the human laryngeal squamous cell carcinoma

Background

Interferon-inducible 16 (IFI16)/caspase-1 inflammasome activates and secretes IL-1β. However, it is still unclear whether the IFI16 inflammasome is involved in human laryngeal squamous cell carcinoma. Autophagy directly removed inflammasome components and limited early IL-1β production. RalB is required for the crosstalk between inflammasome and autophagy in macrophages. Dihydroartemisinin (DHA), the main derived ingredient of artemisinin, has a variety of biological activities. The mechanism of DHA in regulating the crosstalk between IFI16 inflammasome and autophagy by inhibiting RalB expression was analyzed in order to provide clues for new therapeutic methods in laryngeal cancer.

Methods

The expression of IFI16 was analyzed by Oncomine and GEPIA databases and detected by Western blot and immunohistochemistry. The relationship between IFI16 inflammasome and autophagy was investigated by transmission electron microscopy, immunofluorescence assay, etc. in Hep-2, Cal-27 and HeLa cells treated with DHA. The xenograft tumor of hep-2 cell in nude mice were used to assess the effect of DHA on laryngeal cancer.

Results

It was reported for the first time in this study that IFI16 was overexpressed and positively correlated with caspase-1 in laryngeal carcinoma tissues. DHA significantly inhibited the activation of inflammasome and reduced IL-1β production in the microenvironment of Hep-2 cell xenograft tumor in nude mice. Mechanistically, we found that DHA degraded RalB, inhibited USP33 expression, and triggered autophagy. Meanwhile, enhanced autophagy can reduce the expression of RalB and USP33. Furthermore, DHA promotes autophagy, which suppresses the activation of IFI16/caspase-1 inflammasome and IL-1β production.

Conclusions

Therefore, our findings demonstrate that DHA may act as a RalB inhibitor to regulate the crosstalk between autophagy and IFI16/caspase-1 inflammasome, which inhibits IL-1β production in tumor microenvironment.

The Power of Phytochemicals Combination in Cancer Chemoprevention

Conventional therapies for cancer treatment have posed many challenges, including toxicity, multidrug resistance and economic expenses. In contrast, complementary alternative medicine (CAM), employing phytochemicals have recently received increased attention owing to their capability to modulate a myriad of molecular mechanisms with a less toxic effect. Increasing evidence from preclinical and clinical studies suggest that phytochemicals can favorably modulate several signaling pathways involved in cancer development and progression. Combinations of phytochemicals promote cell death, inhibit cell proliferation and invasion, sensitize cancerous cells, and boost the immune system, thus making them striking alternatives in cancer therapy. We previously investigated the effect of six phytochemicals (Indol-3-Carbinol, Resveratrol, C-phycocyanin, Isoflavone, Curcumin and Quercetin), at their bioavailable levels on breast cancer cell lines and were compared to primary cell lines over a period of 6 days. This study showed the compounds had a synergestic effect in inhibiting cell proliferation, reducing cellular migration and invasion, inducing both cell cycle arrest and apoptosis. Despite the vast number of basic science and preclinical cancer studies involving phytochemicals, the number of CAM clinical trials in cancer treatment still remains nascent. In this review, we summarize findings from preclinical and clinical studies, including our work involving use of phytochemicals, individually as well as in combination and further discuss the potential of these phytochemicals to pave way to integrate CAM in primary health care.

Artesunate Affects T Antigen Expression and Survival of Virus-Positive Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is a rare and highly aggressive skin cancer with frequent viral etiology. Indeed, in about 80% of cases, there is an association with Merkel cell polyomavirus (MCPyV); the expression of viral T antigens is crucial for growth of virus-positive tumor cells. Since artesunate—a drug used to treat malaria—has been reported to possess additional anti-tumor as well as anti-viral activity, we sought to evaluate pre-clinically the effect of artesunate on MCC. We found that artesunate repressed growth and survival of MCPyV-positive MCC cells in vitro. This effect was accompanied by reduced large T antigen (LT) expression. Notably, however, it was even more efficient than shRNA-mediated downregulation of LT expression. Interestingly, in one MCC cell line (WaGa), T antigen knockdown rendered cells less sensitive to artesunate, while for two other MCC cell lines, we could not substantiate such a relation. Mechanistically, artesunate predominantly induces ferroptosis in MCPyV-positive MCC cells since known ferroptosis-inhibitors like DFO, BAF-A1, Fer-1 and β-mercaptoethanol reduced artesunate-induced death. Finally, application of artesunate in xenotransplanted mice demonstrated that growth of established MCC tumors can be significantly suppressed in vivo. In conclusion, our results revealed a highly anti-proliferative effect of the approved and generally well-tolerated anti-malaria compound artesunate on MCPyV-positive MCC cells, suggesting its potential usage for MCC therapy.

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

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

A first-in-human proof-of-concept trial of intravaginal artesunate to treat cervical intraepithelial neoplasia 2/3 (CIN2/3)

OBJECTIVE

Most treatment options for cervical intraepithelial neoplasia 2/3 (CIN2/3) are either excisional or ablative, and require sequential visits to health care providers. Artesunate, a compound that is WHO-approved for treatment of acute malaria, also has cytotoxic effect on squamous cells transformed by HPV. We conducted a first-in-human Phase I dose-escalation study to assess the safety and efficacy of self-administered artesunate vaginal inserts in biopsy-confirmed CIN2/3.

METHODS

Safety analyses were based on patients who received at least one dose, and were assessed by the severity, frequency, and duration of reported adverse events. Tolerability was assessed as the percentage of subjects able to complete their designated dosing regimen. Modified intention-to-treat analyses for efficacy and viral clearance were based on patients who received at least one dose for whom endpoint data were available. Efficacy was defined as histologic regression to CIN1 or less. Viral clearance was defined as absence of HPV genotoype (s) detected at baseline.

RESULTS

A total of 28 patients received 1, 2, or 3 five-day treatment cycles at study weeks 0, 2, and 4, respectively, prior to a planned, standard-of-care resection at study week 15. Reported adverse events were mild, and self-limited. In the modified intention-to-treat analysis, histologic regression was observed in 19/28 (67.9%) subjects. Clearance of HPV genotypes detected at baseline occurred in 9 of the 19 (47.4%) subjects whose lesions underwent histologic regression.

CONCLUSIONS

Self-administered vaginal artesunate inserts were safe and well-tolerated, at clinically effective doses to treat CIN2/3. These findings support proceeding with Phase II clinical studies.

The Use of Antimalarial Drugs against Viral Infection

In recent decades, drugs used to treat malaria infection have been shown to be beneficial for many other diseases, including viral infections. In particular, they have received special attention due to the lack of effective antiviral drugs against new emerging viruses (i.e., HIV, dengue virus, chikungunya virus, Ebola virus, etc.) or against classic infections due to drug-resistant viral strains (i.e., human cytomegalovirus). Here, we reviewed the in vitro/in vivo and clinical studies conducted to evaluate the antiviral activities of four classes of antimalarial drugs: Artemisinin derivatives, aryl-aminoalcohols, aminoquinolines, and antimicrobial drugs.

Translationally controlled tumor protein (TCTP) plays a pivotal role in cardiomyocyte survival through a Bnip3-dependent mechanism

Prevention of cardiomyocyte death is an important therapeutic strategy for heart failure. In this study, we focused on translationally controlled tumor protein (TCTP), a highly conserved protein that is expressed ubiquitously in mammalian tissues, including heart. TCTP plays pivotal roles in survival of certain cell types, but its function in cardiomyocytes has not been examined. We aimed to clarify the role of TCTP in cardiomyocyte survival and the underlying mechanism. Here, we demonstrated that downregulation of TCTP with siRNA induced cell death of cardiomyocytes with apoptotic and autophagic features, accompanied with mitochondrial permeability transition pore (mPTP) opening. TCTP loss did not induce cell death of cardiac fibroblasts. Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (Bnip3) was found to mediate the TCTP-loss-induced cardiomyocyte death. In exploring the clinical significance of the TCTP expression in the heart, we found that DOX treatment markedly downregulated the protein expression of TCTP in cultured cardiomyocytes and in mouse heart tissue. Exogenous rescue of TCTP expression attenuated DOX-induced cardiomyocyte death. In mice, cardiomyocyte-specific overexpression of TCTP resulted in decreased susceptibility to DOX-induced cardiac dysfunction, accompanied with attenuated induction of Bnip3. Dihydroartemisinin, a pharmacological TCTP inhibitor, induced development of heart failure and cardiomyocyte death in control mice, but not in mice with cardiomyocyte-specific TCTP overexpression. Our findings revealed TCTP has a pivotal role in cardiomyocyte survival, at least in part through a Bnip3-dependent mechanism. TCTP could be considered as a candidate therapeutic target to prevent DOX-induced heart failure.

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.

Evaluation and Comparison of the Effects of Artesunate, Dexamethasone, and Tacrolimus on Sciatic Nerve Regeneration

PURPOSE

To examine the effect of topical artesunate treatment on peripheral nerve regeneration and compare it with the effects of topical tacrolimus and dexamethasone on nerve regeneration.

MATERIALS AND METHODS

Thirty-two Wistar albino rats were used in this study. The rats were divided into 6 groups: sham, saline, petrolatum, artesunate, tacrolimus, and dexamethasone. A compression injury was generated in the right sciatic nerve in all groups except the sham group. In the sham group, the nerve was dissected but compression was not applied. In the groups in which compression was applied, the agents were absorbed through resorbable gelatin sponges applied to the injured region. At the end of 4 weeks, walking analysis, electromyographic measurements, and histopathologic examinations were conducted.

RESULTS

When the sciatic function index and electrophysiologic measurements were evaluated, artesunate, tacrolimus, and dexamethasone exhibited positive effects on nerve regeneration (P < .05); there were no significant differences among these 3 agents (P > .05). Histopathologic examination showed that artesunate decreased fibrosis scores and inflammation and increased the diameter of myelinated axons; tacrolimus decreased fibroblast scores; and dexamethasone only decreased fibrosis scores (P < .05). Immunohistochemical analysis showed that the artesunate and dexamethasone groups had more positive immunoreactivity to nerve growth factor than did the saline group (P < .05).

CONCLUSIONS

Topical artesunate treatment had a positive effect on peripheral nerve regeneration. There were no relevant differences between the topical forms of dexamethasone and tacrolimus for peripheral nerve regeneration.

Dihydroartemisinin induces autophagy-dependent death in human tongue squamous cell carcinoma cells through DNA double-strand break-mediated oxidative stress

Dihydroartemisinin is an effective antimalarial agent with multiple biological activities. In the present investigation, we elucidated its therapeutic potential and working mechanism on human tongue squamous cell carcinoma (TSCC). It was demonstrated that dihydroartemisinin could significantly inhibit cell growth in a dose- and time-dependent manner by the Cell Counting Kit-8 and colony formation assay in vitro. Meanwhile, autophagy was promoted in the Cal-27 cells treated by dihydroartemisinin, evidenced by increased LC3B-II level, increased autophagosome formation, and increased Beclin-1 level compared to dihydroartemisinin-untreated cells. Importantly, dihydroartemisinin caused DNA double-strand break with simultaneously increased γH2AX foci and oxidative stress; this inhibited the nuclear localization of phosphorylated signal transducer and activator of transcription 3 (p-STAT3), finally leading to autophagic cell death. Furthermore, the antitumor effect of dihydroartemisinin-monotherapy was confirmed with a mouse xenograft model, and no kidney injury associated with toxic effect was observed after intraperitoneal injection with dihydroartemisinin for 3 weeks in vivo. In the present study, it was revealed that dihydroartemisinin-induced DNA double-strand break promoted oxidative stress, which decreased p-STAT3 (Tyr705) nuclear localization, and successively increased autophagic cell death in the Cal-27 cells. Thus, dihydroartemisinin alone may represent an effective and safe therapeutic agent for human TSCC.

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.

Dimeric Cadinane Sesquiterpenoid Derivatives from Artemisia annua

Arteannoide A (1), an unusual cadinane dimer featuring a rare fused 6,8-dioxabicyclo[3.2.l]octan-7-one ring system, arteannoides B and C (2 and 3), two novel heterodimers incorporating a rearranged cadinene sesquiterpenoid and a phenylpropanoid, together with two new rearranged cadinene sesquiterpenoids 4 and 5, were isolated from Artemisia annua L. Their structures were determined by a combination of NMR spectroscopy, electronic circular dichroism calculations, and X-ray diffraction analyses. Compounds 2 and 3 showed inhibition of nitric oxide production in lipopolysaccharide-induced RAW 264.7 mouse macrophage cell lines with IC₅₀ values of 4.5 and 2.9 μM, respectively.

Cancer combination therapy of the sesquiterpenoid artesunate and the selective EGFR-tyrosine kinase inhibitor erlotinib

BACKGROUND

The shift from cytotoxic to targeted chemotherapy led to improved treatment outcomes in oncology. Nevertheless, many cancer patients cannot be cured from their disease because of the development of drug resistance and side effects.

PURPOSE

There is an ongoing quest for novel compounds, which raised not only the interest in natural products but also in novel combination therapy regimens.

STUDY DESIGN

In this review, we report on the inhibition epidermal growth factor receptor (EGFR) by targeted small molecules and their combination with natural products from medicinal plants.

RESULTS

The combination of erlotinib with artesunate leads to synergistic inhibition of cell growth in isobologram analyses. Artesunate is an approved anti-malaria drug, which is also active against cancer as shown in vitro, in vivo and in preliminary clinical phase I/II trials.

CONCLUSION

The combination of natural products (e.g. the sesquiterpenoid artesunate) and synthetic compounds (e.g. the small molecule EGFR tyrosine kinase inhibitor erlotinib) may lead to improved clinical success rates in oncology.

Dihydroartemisinin Sensitizes Human Lung Adenocarcinoma A549 Cells to Arsenic Trioxide via Apoptosis

Recent studies have shown that arsenic trioxide (ATO) is an effective anti-cancer drug for treatment of acute promyelocytic leukemia and other types of human cancer. However, we have found that lung cancer cells constantly develop a high level of resistance to ATO. In this study, we have explored a possibility of combination of dihydroartemisinin (DHA) and ATO treatments to reduce ATO resistance of lung cancer cells. We determined the combinatory effects of DHA and ATO on cytotoxicity of human lung adenocarcinoma (A549) cells. We showed that co-exposure to DHA and ATO of A549 cells synergistically increased the cytotoxicity and apoptotic cell death in the cells. We found that the synergistic effect of DHA and ATO in promoting apoptosis mainly resulted from increased cellular level of reactive oxygen species (ROS) and DNA damage. ATO alone only exerted moderate growth inhibitory effects on A549 cells. The results indicate that DHA can significantly sensitize ATO-induced cytotoxicity of A549 lung cancer cells through apoptosis mediated by ROS-induced DNA damage. Interestingly, we found that the combinatory treatment of DHA and ATO did not result in significant adverse effects in normal human bronchial epithelial (HBE) cells. Our results further provide evidence for the potential application of combinatory effects of DHA and ATO as a safe therapy for human lung cancer.

Functional annotation of chemical libraries across diverse biological processes

Chemical-genetic approaches offer the potential for unbiased functional annotation of chemical libraries. Mutations can alter the response of cells in the presence of a compound, revealing chemical-genetic interactions that can elucidate a compound's mode of action. We developed a highly parallel, unbiased yeast chemical-genetic screening system involving three key components. First, in a drug-sensitive genetic background, we constructed an optimized diagnostic mutant collection that is predictive for all major yeast biological processes. Second, we implemented a multiplexed (768-plex) barcode-sequencing protocol, enabling the assembly of thousands of chemical-genetic profiles. Finally, based on comparison of the chemical-genetic profiles with a compendium of genome-wide genetic interaction profiles, we predicted compound functionality. Applying this high-throughput approach, we screened seven different compound libraries and annotated their functional diversity. We further validated biological process predictions, prioritized a diverse set of compounds, and identified compounds that appear to have dual modes of action.

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.

Uptake of silver nanoparticles by DHA-treated cancer cells examined by surface-enhanced Raman spectroscopy in a microfluidic chip

This paper reports on the synthesis and application of biocompatible and sensitive SERS nanoparticles for the study of uptake of nanoparticles into living cells in a microfluidic chip through surface-enhanced Raman spectroscopy (SERS). The nanoparticles were fabricated as beta-cyclodextrin-coated silver nanoparticles (Ag@CD NPs) modified with para-aminothiophenol (p-ATP) and folic acid (FA) on the surface. The p-ATP molecules act as the Raman reporter while the FA tags have high affinity for folate receptors (FR) that are over-expressed on the surface cancerous cells, so that the nanoparticles can enter the cells and be monitored by the Raman reporter. Therefore, the nanoparticles could be utilized not only as cell invaders due to endocytosis but also as a SERS sensitive probe to monitor the effect of FR-targeted drugs such as dihydroartemisinin (DHA) that induce the population change of FR on the membrane of living cells. As a result, we have successfully demonstrated that we are able to employ the Ag@CD@p-ATP@FA NPs to evaluate the number of NPs entering living cells quantitatively and correspondingly the drug effect on cancer cells in a well-controlled way.

Application of the Triazolization Reaction to Afford Dihydroartemisinin Derivatives with Anti-HIV Activity

Artemisinin and synthetic derivatives of dihydroartemisinin are known to possess various biological activities. Post-functionalization of dihydroartemisinin with triazole heterocycles has been proven to lead to enhanced therapeutic potential. By using our newly developed triazolization strategy, a library of unexplored fused and 1,5-disubstituted 1,2,3-triazole derivatives of dihydroartemisinin were synthesized in a single step. All these newly synthesized compounds were characterized and evaluated for their anti-HIV (Human Immunodeficiency Virus) potential in MT-4 cells. Interestingly; three of the synthesized triazole derivatives of dihydroartemisinin showed activities with half maximal inhibitory concentration (IC₅₀) values ranging from 1.34 to 2.65 µM.

Development of Anticancer Agents from Plant-Derived Sesquiterpene Lactones

Sesquiterpene lactones are of considerable interest due to their potent bioactivities, including cancer cell cytotoxicity and antineoplastic efficacy in in vivo studies. Among these compounds, artesunate, dimethylaminoparthenolide, and L12ADT peptide prodrug, a derivative of thapsigargin, are being evaluated in the current cancer clinical or preclinical trials. Based on the structures of several antitumor sesquiterpene lactones, a number of analogues showing greater potency have been either isolated as natural products or partially synthesized, and some potential anticancer agents that have emerged from this group of lead compounds have been investigated extensively. The present review focuses on artemisinin, parthenolide, thapsigargin, and their naturally occurring or synthetic analogues showing potential anticancer activity. This provides an overview of the advances in the development of these types of sesquiterpene lactones as potential anticancer agents, including their structural characterization, synthesis and synthetic modification, and antitumor potential, with the mechanism of action and structure-activity relationships also discussed. It is hoped that this will be helpful in stimulating the further interest in developing sesquiterpene lactones and their derivatives as new anticancer agents.

The Glutaminase-1 Inhibitor 968 Enhances Dihydroartemisinin-Mediated Antitumor Efficacy in Hepatocellular Carcinoma Cells

Reprogrammed metabolism and redox homeostasis are potential targets of cancer therapy. Our previous study demonstrated that the kidney form of glutaminase (GLS1) is highly expressed in hepatocellular carcinoma (HCC) cells and can be used as a target for effective anticancer therapy. Dihydroartemisinin (DHA) increases intracellular reactive oxygen species (ROS) levels leading to cytotoxicity in cancer cells. However, the heterogeneity of cancer cells often leads to differing responses to oxidative lesions. For instance, cancer cells with high ratio of GSH/GSSG, a critical ROS scavenger, are resistant to ROS-induced cytotoxicity. We postulate that a combinatorial strategy firstly disrupting redox homeostasis followed by DHA might yield a profound antitumor efficacy. In this study, when HCC cells were treated with a GLS1 inhibitor 968, the ROS elimination capacity was significantly reduced in HCC cells, which rendered HCC cells but not normal endothelial cells more sensitive to DHA-mediated cytotoxicity. We further confirmed that this synergistic antitumor efficacy was mediated by excessive ROS generation in HCC cells. NAC, a ROS inhibitor, partly rescued the combinatorial cytotoxic effect of 968 and DHA. Given that GLS1 is a potential antitumor target and DHA has been safely used in clinic, our findings provide new insight into liver cancer therapy targeting glutamine metabolism combined with the ROS generator DHA, which can be readily translated into cancer clinical trials.

Fatal Liver and Bone Marrow Toxicity by Combination Treatment of Dichloroacetate and Artesunate in a Glioblastoma Multiforme Patient: Case Report and Review of the Literature

A 52-year-old male patient was treated with standard radiochemotherapy with temozolomide for glioblastoma multiforme (GBM). After worsening of his clinical condition, further tumor-specific treatment was unlikely to be successful, and the patient seeked help from an alternative practitioner, who administered a combination of dichloroacetate (DCA) and artesunate (ART). A few days later, the patient showed clinical and laboratory signs of liver damage and bone marrow toxicity (leukopenia, thrombocytopenia). Despite successful restoration of laboratory parameters upon symptomatic treatment, the patient died 10 days after the infusion. DCA bears a well-documented hepatotoxic risk, while ART can be considered as safe concerning hepatotoxicity. Bone marrow toxicity can appear upon ART application as reduced reticulocyte counts and disturbed erythropoiesis. It can be assumed that the simultaneous use of both drugs caused liver injury and bone marrow toxicity. The compassionate use of DCA/ART combination therapy outside of clinical trials cannot be recommended for GBM treatment.