Dihydroartemisinin inhibits tumor growth of human osteosarcoma cells by suppressing Wnt/β-catenin signaling

Overcoming drug resistance in osteosarcoma with MTX-CuB-NLC: An in vitro and in vivo study

Osteosarcoma (OS) is the predominant bone tumor affecting pediatric and adolescent populations. The standard treatment regimen involves preoperative chemotherapy, surgical intervention, and postoperative chemotherapy. Methotrexate (MTX) serves as the first-line pharmacological agent for OS treatment; however, the emergence of tumor resistance to chemotherapeutic agents poses a significant challenge. Cucurbitacin B (CuB) exhibits intrinsic anti-OS properties and can synergistically enhance OS suppression by reversing drug resistance and augmenting the therapeutic effects of MTX. Nevertheless, the clinical application of CuB and MTX is hindered by their low aqueous solubility, necessitating the development of an effective drug delivery system to precisely target tumor tissues and maximize therapeutic efficacy. Consequently, this study focuses on the development of a nanostructured lipid carrier (NLC) co-loaded with MTX and CuB (MTX-CuB-NLC) to address these limitations. MTX-CuB-NLC is characterized as a spherical nanoparticle with a mean particle size of 44.13 ± 1.40 nm, a polydispersity index (PDI) of 0.279 ± 0.120, and a zeta potential of -17.10 ± 4.98 mV. The encapsulation efficiency (EE%) and drug loading (DL%) were determined to be 61.03 ± 2.40 % and 0.25 ± 0.02 % for MTX, and 81.02 ± 1.61 % and 0.23 ± 0.02 % for CuB, respectively. The formulation demonstrated substantial storage stability over a 14-day period. In vitro release studies indicated that MTX-CuB-NLC possesses sustained release capabilities. Furthermore, the nanoparticle exhibited significantly enhanced uptake and cytotoxicity against U-2 OS cells compared to the free drug. Notably, MTX-CuB-NLC displayed pronounced cytotoxic effects on methotrexate-resistant U-2 OS cells (U-2 OS/MTX), underscoring its potential to induce apoptosis and circumvent multidrug resistance in these cells. In an OS nude mouse model exhibiting drug resistance, MTX-CuB-NLC demonstrated superior tumor targeting and suppression efficacy. This research has culminated in the development of an effective continuous drug delivery system for osteosarcoma, presenting a promising strategy to combat drug resistance in this malignancy.

Wnt/β-catenin signaling pathway: an attractive potential therapeutic target in osteosarcoma

Osteosarcoma (OS) is the most common bone malignancy in children and adolescents, and although current neoadjuvant chemotherapy has shown efficacy against OS, the long-term survival rate for patients with OS remains low, highlighting the need to find more effective treatments. In cancer cells, abnormal activation of signaling pathways can widely affect cell activity from growth and proliferation to apoptosis, invasion and metastasis. Wnt/β-catenin is a complex and unique signaling pathway that is considered to be one of the most important carcinogenic pathways in human cancer. Research have confirmed that the Wnt/β-catenin signaling pathway is an important driving factor for the occurrence and development of osteosarcoma, and abnormal activation of this pathway can promote the pathological processes of cell proliferation, invasion, migration, tumor angiogenesis and chemical resistance of osteosarcoma. However, inhibition of Wnt/β-catenin signaling pathway can effectively inhibit or reverse the above pathological processes. Therefore, manipulating the expression or function of the Wnt/β-catenin pathway may be a potential targeted pathway for the treatment of OS. In this review, we describe the characteristics of the Wnt/β-catenin signaling pathway and summarize the role and mechanism of this pathway in OS. This paper discusses the therapeutic significance of inhibiting or targeting Wnt/β-catenin pathway in OS and the shortcomings of current studies on this pathway in OS and the problems to be solved. This review helps us to understand the role of Wnt/β-catenin on OS, and provides a theoretical basis and new ideas for targeting Wnt/β-catenin pathway as a therapeutic target for OS.

Ferroptosis and its implications in bone-related diseases

Ferroptosis, a recently recognized form of regulated cell death (RCD) characterized by iron-dependent lipid peroxide accumulation, has emerged as a noteworthy regulator in various bone-related diseases, including osteoporosis (OP), osteoarthritis (OA), and osteosarcoma (OS). OS primarily afflicts the elderly, rendering them susceptible to fractures due to increased bone fragility. OA represents the most prevalent arthritis in the world, often observed in the aging population. OS predominantly manifests during adolescence, exhibiting an aggressive nature and bearing a significantly unfavorable prognosis. In this review article, we present an overview of the characteristics and mechanism of ferroptosis and its involvement in bone-related diseases, with a particular focus on OP, OA, and OS. Furthermore, we summarize chemical compounds or biological factors that impact bone-related diseases by regulating ferroptosis. Through an in-depth exploration of ferroptosis based on current research findings, this review provides promising insights for potential therapeutic approaches to effectively manage and mitigate the impact of these bone-related pathological conditions.

Amicis Omnia Sunt Communia: NF-κB Inhibition as an Alternative to Overcome Osteosarcoma Heterogeneity

Tumor heterogeneity poses a significant challenge in osteosarcoma (OS) treatment. In this regard, the "omics" era has constantly expanded our understanding of biomarkers and altered signaling pathways (i.e., PI3K/AKT/mTOR, WNT/β-catenin, NOTCH, SHH/GLI, among others) involved in OS pathophysiology. Despite different players and complexities, many commonalities have been described, among which the nuclear factor kappa B (NF-κB) stands out. Its altered activation is pervasive in cancer, with pleiotropic action on many disease-relevant traits. Thus, in the scope of this article, we highlight the evidence of NF-κB dysregulation in OS and its integration with other cancer-related pathways while we summarize the repertoire of compounds that have been described to interfere with its action. In silico strategies were used to demonstrate that NF-κB is closely coordinated with other commonly dysregulated signaling pathways not only by functionally interacting with several of their members but also by actively participating in the regulation of their transcription. While existing inhibitors lack selectivity or act indirectly, the therapeutic potential of targeting NF-κB is indisputable, first for its multifunctionality on most cancer hallmarks, and secondly, because, as a common downstream effector of the many dysregulated pathways influencing OS aggressiveness, it turns complex regulatory networks into a simpler picture underneath molecular heterogeneity.

Targeting signaling pathways in osteosarcoma: Mechanisms and clinical studies

Osteosarcoma (OS) is a highly prevalent bone malignancy among adolescents, accounting for 40% of all primary malignant bone tumors. Neoadjuvant chemotherapy combined with limb-preserving surgery has effectively reduced patient disability and mortality, but pulmonary metastases and OS cells' resistance to chemotherapeutic agents are pressing challenges in the clinical management of OS. There has been an urgent need to identify new biomarkers for OS to develop specific targeted therapies. Recently, the continued advancements in genomic analysis have contributed to the identification of clinically significant molecular biomarkers for diagnosing OS, acting as therapeutic targets, and predicting prognosis. Additionally, the contemporary molecular classifications have revealed that the signaling pathways, including Wnt/β-catenin, PI3K/AKT/mTOR, JAK/STAT3, Hippo, Notch, PD-1/PD-L1, MAPK, and NF-κB, have an integral role in OS onset, progression, metastasis, and treatment response. These molecular classifications and biological markers have created new avenues for more accurate OS diagnosis and relevant treatment. We herein present a review of the recent findings for the modulatory role of signaling pathways as possible biological markers and treatment targets for OS. This review also discusses current OS therapeutic approaches, including signaling pathway-based therapies developed over the past decade. Additionally, the review covers the signaling targets involved in the curative effects of traditional Chinese medicines in the context of expression regulation of relevant genes and proteins through the signaling pathways to inhibit OS cell growth. These findings are expected to provide directions for integrating genomic, molecular, and clinical profiles to enhance OS diagnosis and treatment.

Baicalin induces ferroptosis in osteosarcomas through a novel Nrf2/xCT/GPX4 regulatory axis

BACKGROUND

Osteosarcomas (OS) is a kind of malignant bone tumor which occurs primarily in children and adolescents, and the clinical therapeutics remain disappointing. As a new programmed cell death, ferroptosis is characterized by iron dependent and intracellular oxidative accumulation, which provides a potential alternative intervene for the OS treatment. Baicalin, a major bioactive flavone derived from traditional Chinese medicine Scutellaria baicalensis, has been proved to have anti-tumor properties in OS. Whether ferroptosis participated in the baicalin mediated anti-OS activity is an interesting project.

PURPOSE

To explore the pro-ferroptosis effect and mechanisms of baicalin in OS.

METHODS/STUDY DESIGN

Pro-ferroptosis effect of baicalin on cell death, cell proliferation, iron accumulation, lipid peroxidation production was determined in MG63 and 143B cells. The levels of glutathione (GSH), oxidized (GSSG) glutathione and malondialdehyde (MDA) were determined by enzyme linked immunosorbent assay (ELISA). The expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), Glutathione peroxidase 4 (GPX4) and xCT were detected by western blot in baicalin-mediated ferroptosis regulation. In vivo, a xenograft mice model was adopted to explore the anticancer effect of baicalin.

RESULTS

In the present study, it was found that baicalin significantly suppress tumor cell growth in vitro and in vivo. By promoting the Fe accumulation, ROS formation, MDA production and suppressing the ratio of GSH/GSSG, baicalin was found to trigger ferroptosis in OS and ferroptosis inhibitor ferrostatin-1 (Fer-1) successfully reversed these suppressive effects, indicating that ferroptosis participated in the baicalin mediated anti-OS activity. Mechanistically, baicalin physically interacted with Nrf2, a critical regulator of ferroptosis, and influenced its stability via inducing ubiquitin degradation, which suppressed the Nrf2 downstream targets GPX4 and xCT expression, and led to stimulating ferroptosis.

CONCLUSIONS

Our findings for the first time indicated that baicalin exerted anti-OS activity through a novel Nrf2/xCT/GPX4-dependent ferroptosis regulatory axis, which hopefully provides a promising candidate for OS treatment.

Chemical hybridization of sulfasalazine and dihydroartemisinin promotes brain tumor cell death

Gliomas are primary brain tumors with still poor prognosis for the patients despite a combination of cytoreduction via surgery followed by a radio-chemotherapy. One strategy to find effective treatment is to combine two different compounds in one hybrid molecule via linker to add to or at best potentiate their impact on malignant cells. Here, we report on the effects of a newly synthesized hybrid of sulfasalazine (SAS) and dihydroartemisinin (DHA), called AC254. In previous studies, both SAS and DHA have already proved to have anti-tumor properties themselves and to have sensitizing respectively potentiating effects on other treatments against malignant tumors. We investigated the impact of individual drugs SAS and DHA, their 1:1 combination and a novel SAS-DHA hybrid compound (AC254) on rodent and human glioma cells. In our study SAS alone showed no or only a mild effect on glioma, whereas DHA led to a significant reduction of cell viability in a dose-dependent manner. Next we compared the efficacy of the hybrid AC254 to the combinational treatment of its parent compounds SAS and DHA. The hybrid was highly efficient in combating glioma cells compared to single treatment strategies regarding cell viability and cell death. Interestingly, AC254 showed a remarkable advantage over the combinational treatment with both parent compounds in most used concentrations. In addition to its reduction of tumor cell viability and induction of cell death, the hybrid AC254 displayed changes in cell cycle and reduction of cell migration. Taken together, these results demonstrate that clinically established compounds such as SAS and DHA can be potentiated in their anti-cancer effects by chemical hybridization. Thus, this concept provides the opportunity to devise new effective chemotherapeutic agents.

Targeted Lipid Nanoparticles Encapsulating Dihydroartemisinin and Chloroquine Phosphate for Suppressing the Proliferation and Liver Metastasis of Colorectal Cancer

Antimalarial drugs Dihydroartemisinin (DHA) and chloroquine phosphate (CQ) exhibit evident anti-cancer activity, particularly as combination therapy. DHA and CQ combination therapy has been proved to exhibit higher cytotoxic effect in tumor cells and lower toxicity to normal cells than combination of artemisinin derivatives (ARTs) and anticancer chemotherapy drugs. However, different physiochemical properties of DHA and CQ, leading to distinctive in vivo outcomes, considerably limited their synergistic effect in cancer treatment. Herein, we developed a lipid nanoparticle (LNP) for co-delivery of DHA and CQ to inhibit proliferation and metastasis of colorectal cancer. Considering the beneficial effects of acid/reactive oxide species (ROS)-sensitive phospholipids and targeting ligands for colorectal cancer cells, an RGD peptide-modified pH/ROS dual-sensitive LNP loaded with DHA and CQ (RLNP/DC) was prepared. It exhibited optimal cytotoxicity and suppression of invasion and metastasis in HCT116 cells in vitro, attributable to irreversible upregulation of intracellular ROS levels, downregulation of VEGF expression, and upregulation of paxillin expression. A mouse model of orthotopic metastasis of colorectal cancer was established to evaluate anti-proliferation and anti-metastasis effects of RLNP/DC in vivo. Thus, an optimized nanoplatform for DHA and CQ combination therapy was developed in this study that offered potential antitumor efficacy against colorectal cancer.

Mechanisms and Molecular Targets of Artemisinin in Cancer Treatment

The major problems with cancer therapy are drug-induced side effects. There is an urgent need for safe anti-tumor drugs. Artemisinin is a Chinese herbal remedy for malaria with efficacy and safety. However, several studies reported that artemisinin causes neurotoxicity and cardiotoxicity in animal models. Recently, nanostructured drug delivery systems have been designed to improve therapeutic efficacy and reduce toxicity. Artemisinin has been reported to show anticancer properties. The anticancer effects of artemisinin appear to be mediated by inducing cell cycle arrest, promoting ferroptosis and autophagy, inhibiting cell metastasis. Therefore, the review is to concentrate on mechanisms and molecular targets of artemisinin as anti-tumor agents. We believe these will be important topics in realizing the potential of artemisinin and its derivatives as potent anticancer agents.

Dihydroartemisinin Attenuates Pulmonary Hypertension Through Inhibition of Pulmonary Vascular Remodeling in Rats

Pulmonary arterial hypertension (PAH) is a malignant disease characterized by pulmonary arterial remodeling because of the abnormal proliferation and migration of pulmonary arterial smooth muscle cells. Dihydroartemisinin (DHA), an artemisinin derivative used to treat malaria, is able to inhibit fibrosis, neovascularization, and tumor proliferation. In this study, we hypothesized that DHA can be beneficial in treating PAH. To test this hypothesis, a rat model of pulmonary hypertension induced with monocrotaline (MCT) was used. Compared with MCT treatment alone, treatment with 50 or 100 mg/kg DHA significantly reduced the mean pulmonary arterial pressure (30.11 ± 2.48 mm Hg vs. 21.35 ± 3.04 mm Hg and 19.18 ± 1.98 mm Hg, respectively, both P < 0.01), right ventricular transverse diameter (4.36 ± 0.41 mm vs. 3.72 ± 0.24 mm and 3.67 ± 0.27 mm, respectively, both P < 0.01), pulmonary artery medial wall thickness (57.93 ± 11.14% vs. 34.45 ± 4.39% and 25.01 ± 6.66%, respectively, both P < 0.01), and increased tricuspid annular plane systolic excursion (1.34 ± 0.17 mm vs. 1.62 ± 0.3 mm and 1.62 ± 0.16 mm, respectively, both P < 0.05). We also found that DHA inhibited platelet-derived growth factor-BB-mediated pulmonary arterial smooth muscle cells proliferation and migration in a dose-dependent manner. Moreover, DHA downregulated β-catenin levels while upregulating the levels of axis inhibition protein 2 (Axin2) and glycogen synthase kinase 3β (GSK-3β). Our findings suggest that DHA, which may be a potential candidate for PAH therapy, attenuates experimental pulmonary hypertension possibly by inhibiting pulmonary vascular remodeling.

Therapeutic Potentials and Mechanisms of Artemisinin and its Derivatives for Tumorigenesis and Metastasis

BACKGROUND

Tumor recurrence and metastasis are still leading causes of cancer mortality worldwide. The influence of traditional treatment strategies against metastatic tumors may still be limited. To search for novel and powerful agents against tumors has become a major research focus. In this study, Artemisinin (ARM), a natural compound isolated from herbs, Artemisia annua L., proceeding from drug repurposing methods, attracts more attention due to its good efficacy and tolerance in antimalarial practices, as well as newly confirmed anticancer activity.

METHODS

We have searched and reviewed the literatures about ARM and its derivatives (ARMs) for cancer using keywords "artemisinin" until May 2019.

RESULTS

In preclinical studies, ARMs can induce cell cycle arrest and cell death by apoptosis etc., to inhibit the progression of tumors, and suppress EMT and angiogenesis to inhibit the metastasis of tumors. Notably, the complex relationships of ARMs and autophagy are worth exploring. Inspired by the limitations of its antimalarial applications and the mechanical studies of artemisinin and cancer, people are also committed to develop safer and more potent ARM-based modified compounds (ARMs) or combination therapy, such as artemisinin dimers/ trimers, artemisinin-derived hybrids. Some clinical trials support artemisinins as promising candidates for cancer therapy.

CONCLUSION

ARMs show potent therapeutic potentials against carcinoma including metastatic tumors. Novel compounds derived from artemisinin and relevant combination therapies are supposed to be promising treatment strategies for tumors, as the important future research directions.

Dihydroartemisinin inhibits the tumorigenesis and metastasis of breast cancer via downregulating CIZ1 expression associated with TGF-β1 signaling

AIMS

Dihydroartemisinin (DHA) is currently considered as the promising cancer therapeutic drug. In this study, we aimed to investigate the anti-proliferative and anti-metastasis effects of DHA.

MAIN METHODS

Utilizing breast cancer cells MCF-7, MDA-MB-231 and BT549, cell proliferation, migration and invasion were detected. RT-qPCR was performed to detect CIZ1, TGF-β1 and Snail expression, and the interactions of these related molecules were analyzed by GeneMANIA database. Western blot detected CIZ1, TGF-β1/Smads signaling and Snail expression in DHA-treated cells, in TGFβ1-induced cells with enhanced metastatic capacity, and in cells treated with DHA plus TGFβ1/TGFβ1 inhibitor SD-208.

KEY FINDINGS

Results indicated DHA inhibited breast cancer cell proliferation and migration, with more potent effects compared with that of artemisinin. RT-qPCR and Western blot showed DHA inhibited CIZ1, TGF-β1 and Snail expression, and these molecules were shown to have protein-protein interactions by bioinformatics. Furthermore, TGFβ1-treatment enhanced MCF-7 migration and invasion, and CIZ1, TGF-β1/Smads signaling and snail activities; DHA, SD-208, combination of DHA and SD-208 reversed these conditions, preliminarily proving the cascade regulation between TGF-β1 signaling and CIZ1. MCF-7 xenografts model demonstrated the inhibition of DHA on tumor burden, and its mechanisms and well-tolerance in vivo; combination of DHA and SD-208 tried by us for the first time showed better treatment effects, but possible liver impairment made its use still keep cautious.

SIGNIFICANCE

DHA treatment inhibits the proliferation and metastasis of breast cancer, through suppressing TGF-β1/Smad signaling and CIZ1, suggesting the promising potential of DHA as a well-tolerated antitumor TGF-β1 pathway inhibitor.

Dihydrotanshinone I inhibits the growth of osteosarcoma through the Wnt/β-catenin signaling pathway

Background: Osteosarcoma is a common malignant tumor, with relatively lower survival rates in adolescents. Dihydrotanshinone I (DHI) was extracted from the traditional Chinese medicine Salvia miltiorrhiza and was shown to inhibit several types of cancer. Purpose: To explore the effect of DHI on the proliferation, migration, invasion, and apoptosis of osteosarcoma cells, as well as the possible molecular mechanism. Methods: The effect of DHI on the proliferation of osteosarcoma was detected by crystal violet assay, MTT assay, colony formation assay. The effects of DHI on the migration and invasion of osteosarcoma were detected by wound healing assays, cell migration and invasion assays. The effect of DHI on apoptosis of osteosarcoma was detected by cell apoptosis assay and Hoechst apoptosis staining. The protein expression levels were detected by Western blotting assay. The activity of Wnt/β-Catenin signaling pathway was detected by luciferase reporter assay and Western blot. The inhibitory effect of DHI on osteosarcoma in vivo was analyzed by an orthotopic OS tumor animal model and immunohistochemistry. Result: DHI may inhibit the proliferation, decrease the migration, reduce the invasion, and promote the apoptosis of osteosarcoma cells. In vivo mouse model, DHI can inhibit the formation of osteosarcoma. In terms of mechanism, DHI may inhibit both the transcriptional activity and the total protein level of β-catenin. Conclusion: DHI may inhibit the proliferation, migration, and invasion as well as induce the apoptosis of osteosarcoma cells, possibly through suppressing the Wnt/β-catenin signaling pathway.

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

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

Effects of magnetic dihydroartemisinin nano-liposome in inhibiting the proliferation of head and neck squamous cell carcinomas

BACKGROUND

Dihydroartemisinin (DHA) was one of the most potent anticancer artemisinin-like compounds that had been proved by many researchers, but its application was limited by its own characteristics.

PURPOSE

Magnetic DHA nano-liposomes (DHA-MLPs) were developed to improve the targeting antitumor efficiency and bioavailability of DHA, and their physical properties were characterized.

STUDY DESIGN AND METHODS

Liposomes were prepared by thin film dispersion and orthogonal experimental design was used to optimize the formula. The magnetic targeting and antitumor effects of DHA-MLPs in the externally applied magnetic field was investigated in vitro and in vivo.

RESULTS

The mean particle size of DHA-MLPs was 209.10 ± 4.92 nm, the charge potential was -37.13 ± 1.01 mV, the encapsulation efficiency (E.E.%) was 82.12 ± 0.91%, and the saturation magnetization at room temperature was 11.84 emu g^-1. Targeting DHA-MLPs as well as free DHA could lead to cell cycle G₁ block and apoptosis of HNSCC tumor cells in vitro. The tumor volumes of targeting DHA-MLPs treated mouse group were distinctly decreased than that in the control group, free DHA group and non-targeting DHA-MLPs group (P < 0.05). It was observed from iron staining intensity that DHA-MLPs had significant targeting effect in magnetic field (P < 0.05).

CONCLUSION

This novelty liposome could strengthen the ability of DHA in tumor suppression, by increasing the targeted delivery of DHA and biocompatibility, optimize the bioefficacy of DHA.

Chinese Herbal Medicine for Osteosarcoma in the Mouse: A Systematic Review and Meta-Analysis

OBJECTIVE

To summarize and critically assess the inhibitory effects of Chinese herbal medicine (CHM) on tumor volume and tumor weight for the treatment of osteosarcoma (OS) in mouse models.

METHODS

PubMed, Embase, Web of Science, China Knowledge Resource Integrated Database (CNKI), Wanfang Database, VIP Database, and Chinese BioMedical (CBM) were searched since their inception dates to March 10, 2016. Two reviewers independently selected the controlled studies estimating effects of CHM on mouse OS by administration in vivo. A pair-wise meta-analysis was performed. Twenty-five studies with adequate randomization were included in the systematic review.

RESULTS

CHM may significantly inhibit OS growth in mice, as assessed using the tumor weight [20 studies, n=443; 290 for CHM and 153 for the control: pooled mean difference (MD)=-2.90; 95% confidence interval (Cl): -3.50 to -2.31: P<0.01], tumor volume (16 studies, n=382; 257 for CHM and 125 for the control; pooled MD =-2.57; 95% Cl: -3.33 to -1.80; P<0.01) and tumor growth inhibition rate.

CONCLUSION

CHM could significantly inhibit the growth of OS in mouse models, which might be supportive for the design of preclinical and clinical trials in future.

Opening of the CLC-3 chloride channel induced by dihydroartemisinin contributed to early apoptotic events in human poorly differentiated nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a specific type of head and neck cancer that is prevalent in Southeast Asia. Dihydroartemisinin (DHA), a semisynthetic derivative of artemisinin, has specific anticancer activity. Here, we aimed to investigate the role of the CLC-3 chloride channel in the anticancer effect of DHA in poorly differentiated NPC CNE-2Z cells. First, we observed that DHA could specifically inhibit the proliferation, induce apoptosis, and increase cleaved caspase-3 expression in the CNE-2Z cells. Then, we found that DHA could activate chloride channels, which led to Cl^- efflux and apoptotic volume decrease (AVD) in the early stage in the CNE-2Z cells. DHA also specifically increased CLC-3 chloride channel protein expression in the CNE-2Z cells. Silencing of the CLC-3 protein expression depleted the Cl^- currents, and decreased the AVD capacity and cell apoptosis induced by DHA. Finally, we revealed that the [Ca²⁺ ]_i increased after around 6 hours of treatment with DHA, which was also inhibited by silencing of the CLC-3 protein expression. Our data demonstrated that the selective antitumor activities of DHA in NPC may occur through the specific activation of the CLC-3 Cl^- channel, leading to Cl^- efflux, and induced AVD, then led to [Ca²⁺ ]_i accumulation and caspase-3 activation, and finally induced apoptosis. The activation of the CLC-3 chloride channel played an essential and proximal upstream role in the antitumor activities of DHA.

Novel lymphoid enhancer-binding factor 1-cytoglobin axis promotes extravasation of osteosarcoma cells into the lungs

Lung metastasis is a major cause of mortality in patients with osteosarcoma (OS). A better understanding of the molecular mechanism of OS lung metastasis may facilitate development of new therapeutic strategies to prevent the metastasis. We have established high- and low-metastatic sublines (LM8-H and LM8-L, respectively) from Dunn OS cell line LM8 by using in vivo image-guided screening. Among the genes whose expression was significantly increased in LM8-H compared to LM8-L, the transcription factor lymphoid enhancer-binding factor 1 (LEF1) was identified as a factor that promotes LM8-H cell extravasation into the lungs. To identify downstream effectors of LEF1 that are involved in OS lung metastasis, 13 genes were selected based on LM8 microarray data and genomewide meta-analysis of a public database for OS patients. Among them, the cytoglobin (Cygb) gene was identified as a key effector in promoting OS extravasation into the lungs. CYGB overexpression increased the extravasation ability of LM8-L cells, whereas knocking out the Cygb gene in LM8-H cells reduced this ability. Our results showed a novel LEF1-CYGB axis in OS lung metastasis and may provide a new way of developing therapeutic strategies to prevent OS lung metastasis.

Antitumor Research on Artemisinin and Its Bioactive Derivatives

Cancer is the leading cause of human death which seriously threatens human life. The antimalarial drug artemisinin and its derivatives have been discovered with considerable anticancer properties. Simultaneously, a variety of target-selective artemisinin-related compounds with high efficiency have been discovered. Many researches indicated that artemisinin-related compounds have cytotoxic effects against a variety of cancer cells through pleiotropic effects, including inhibiting the proliferation of tumor cells, promoting apoptosis, inducing cell cycle arrest, disrupting cancer invasion and metastasis, preventing angiogenesis, mediating the tumor-related signaling pathways, and regulating tumor microenvironment. More importantly, artemisinins demonstrated minor side effects to normal cells and manifested the ability to overcome multidrug-resistance which is widely observed in cancer patients. Therefore, we concentrated on the new advances and development of artemisinin and its derivatives as potential antitumor agents in recent 5 years. It is our hope that this review could be helpful for further exploration of novel artemisinin-related antitumor agents.

Dihydroartemisinin sensitizes Lewis lung carcinoma cells to carboplatin therapy via p38 mitogen-activated protein kinase activation

Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin isolated from the traditional Chinese herb Artemisia annua, is an effective novel antimalarial agent. Studies have suggested that it also exhibits anticancer effects when administered alone or in combination with conventional chemotherapeutic agents. The present study investigated the therapeutic effect of DHA combined with carboplatin (CBP) on Lewis lung carcinoma (LLC) cells and the possible underlying molecular mechanisms. MTT and clonogenic assays demonstrated that the proliferation activity of LLC cells was inhibited in a dose-dependent manner by DHA combined with CBP. In addition, flow cytometry analysis revealed that cell cycle arrest was induced at the G₀/G₁ phase and apoptosis was induced following treatment with the combination. When administered in combination with CBP, DHA exhibited more effective anticancer activity compared with DHA or CBP used alone, via increased apoptosis. Following treatment with DHA with or without CBP, the expression of phosphorylated-p38 mitogen-activated protein kinase (MAPK), which can be inhibited with the selective inhibitor SB202190, was detected by western blotting. To summarize, the results of the present study indicated that DHA may sensitize LLC cells to CBP therapy via the activation of p38MAPK, which suggests that a combined treatment of DHA and CBP may be a potential novel therapeutic schedule for lung adenocarcinoma.

Retracted Article: Overexpression of PCDH8 inhibits proliferation and invasion, and induces apoptosis in papillary thyroid cancer cells

Protocadherin8 (PCDH8), a member of the protocadherin (PCDH) family, is involved in the progression of several types of cancers. However, the expression and biological roles of PCDH8 in papillary thyroid carcinoma (PTC) remain largely unknown. Therefore, in the present study, we detected the expression of PCDH8 in human PTC tissues and cell lines, and evaluated its role in PTC cells. Our results demonstrated that PCDH8 was lowly expressed in human PTC tissues and cell lines. In addition, ectopic expression of PCDH8 efficiently inhibited the proliferation, migration and invasion of PTC cells, as well as prevented the epithelial-mesenchymal transition (EMT) phenotype in PTC cells. Furthermore, PCDH8 efficiently induced apoptosis and autophagy in PTC cells. Mechanistically, overexpression of PCDH8 significantly prevented the activation of the Wnt/β-catenin pathway in PTC cells. Taken together, these findings showed that overexpression of PCDH8 inhibits proliferation and migration/invasion, and induces apoptosis of PTC cells through the Wnt/β-catenin signaling pathway.

Protocadherin8 (PCDH8), a member of the protocadherin (PCDH) family, is involved in the progression of several types of cancers.

Dihydroartemisinin inhibits catabolism in rat chondrocytes by activating autophagy via inhibition of the NF-κB pathway

Osteoarthritis is a disease with inflammatory and catabolic imbalance in cartilage. Dihydroartemisinin (DHA), a natural and safe anti-malarial agent, has been reported to inhibit inflammation, but its effects on chondrocytes have yet to be elucidated. We investigated the effects of DHA on catabolism in chondrocytes. Viability of SD rats chondrocytes was analyzed. Autophagy levels were determined via expression of autophagic markers LC3 and ATG5, GFP-LC3 analysis, acridine orange staining, and electron microscopy. ATG5 siRNA induced autophagic inhibition. Catabolic gene and chemokine expression was evaluated using qPCR. The NF-κB inhibitor SM7368 and p65 over-expression were used to analyze the role of NF-κB pathway in autophagic activation. A concentration of 1 μM DHA without cytotoxicity increased LC3-II and ATG5 levels as well as autophagosomal numbers in chondrocytes. DHA inhibited TNF-α-induced expression of MMP-3 and -9, ADAMTS5, CCL-2 and -5, and CXCL1, which was reversed by autophagic inhibition. TNF-α-stimulated nuclear translocation and degradation of the p65 and IκBα proteins, respectively, were attenuated in DHA-treated chondrocytes. NF-κB inhibition activated autophagy in TNF-α-treated chondrocytes, but p65 over-expression reduced the autophagic response to DHA. These results indicate that DHA might suppress the levels of catabolic and inflammatory factors in chondrocytes by promoting autophagy via NF-κB pathway inhibition.

Overexpression of miR-506 suppresses proliferation and promotes apoptosis of osteosarcoma cells by targeting astrocyte elevated gene-1

There is increasing evidence that microRNAs (miRs) are implicated in tumor development and progression; however, their specific roles in osteosarcoma are not well understood. The aim of the present study was to investigate the role of miR-506 in the pathogenesis of osteosarcoma. The expression levels of miR-506 and astrocyte elevated gene-1 (AEG-1) mRNA were detected using quantitative polymerase chain reaction, and the protein levels of AEG-1, β-catenin, c-myc and cyclin D1 were determined using western blot analysis. The effects of miR-506 and AEG-1 on cell viability, colony forming ability and apoptosis were assessed using MTT assay, colony formation assay, and flow cytometry, respectively. Lucifer reporter assays were used to demonstrate whether AEG-1 is a direct target of miR-506. The present study identified that miR-506 was downregulated in osteosarcoma tissues and cells. Overexpression of miR-506 suppressed the proliferation and induced apoptosis in osteosarcoma cells in vitro and inhibited tumor formation in vivo. Overexpression of miR-506 significantly inhibited the luciferase activity of AEG-1 with a wild-type 3′-untranslated region, providing clear evidence that AEG-1 was a direct and functional downstream target of miR-506. Similar to the overexpression of miR-506, downregulation of AEG-1 lead to an inhibitory effect on osteosarcoma in vitro. Furthermore, overexpression of miR-506 or downregulation of AEG-1 inhibited the Wnt/β-catenin signaling pathway, and inhibition of this pathway by β-catenin small interfering RNA or CGP049090, a small molecule inhibitor, suppressed cell proliferation and induced apoptosis in vitro. Overall, the present data indicated that miR-506 functions as a tumor suppressor by targeting AEG-1 in osteosarcoma via the regulation of the Wnt/β-catenin signaling pathway.

Mechanism of dihydroartemisinin-induced apoptosis in prostate cancer PC3 cells: An iTRAQ-based proteomic analysis

AIMS

Prostate cancer (PCa) is one of the most common cancers in men in the world. Advanced PCa, especially castration-resistant PCa (CRPC), is difficult to cure. There is an urgent need to develop novel agents for CPRC. Dihydroartemisinin (DHA) is a semisynthetic derivative of artemisinin and is a well-known antimalarial drug. DHA has been documented to be a potential anticancer agent for PCa. However, the mechanisms underlying the anticancer activity of DHA are still unknown.

MAIN METHODS

Proteomics analysis based on iTRAQ technology was performed to determine the protein profile changes in human prostate cancer PC3 cells treated by DHA, and apoptosis was detected by flow cytometry and transmission electron microscopy.

KEY FINDINGS

DHA induced obvious apoptosis in PC3 cells. Using iTRAQ technology, we found 86 differentially expressed proteins linked to the cytotoxicity of DHA in PC3 cells. Gene ontology analysis showed the differentially expressed proteins were mainly associated with the protein synthesis and translation. Protein interaction network analysis and KEGG pathway analysis revealed altered aminoacyl-tRNA biosynthesis and metabolic pathways. Moreover, one candidate protein, heat shock protein HSP70 (HSPA1A), was identified by western blot analysis.

SIGNIFICANCE

Our results indicate that multiple mechanisms involved in the anticancer activity of DHA in PC3 cells. Decreased HSP70 expression may have an important role in DHA-induced apoptosis in PC3 cells. Our data also provide novel insights into the anticancer mechanisms of DHA.

The tumor suppressive role of RASSF1A in osteosarcoma through the Wnt signaling pathway

Ras-association domain family 1 isoform A (RASSF1A) is a tumor suppressor gene and its expression is lost in numerous types of cancer cells, including primary osteosarcoma cells. However, its functional significance in osteosarcoma has not been well defined. The messenger RNA (mRNA) expression of RASSF1A in osteosarcoma tissues and corresponding non-tumoral tissues was measured by real-time PCR. Overexpression of RASSF1A was established by an adenoviral vector expressing RASSF1A. Cell migration and invasion were analyzed in transwells. Apoptosis and cell cycle were analyzed using flow cytometry. Wnt/β-catenin activity was measured by TCF reporter dual-luciferase assay. Cell viability was measured by MTT assay. Protein expression was detected by Western blot. RASSF1A mRNA expression was significantly lower in osteosarcoma tissues than that in the corresponding non-tumoral tissues. The lowered RASSF1A expression correlated with the clinical severity of osteosarcoma. rAd-RASSF1A injection significantly inhibited the growth of xenograft MNNG/HOS tumors in mice. Overexpression of RASSF1A resulted in significant inhibition of the proliferation, migration, and invasion; induced apoptosis; and arrested cell cycle at G0/G1 phase in both the MNNG/HOS and SaOS2 cells. Overexpression of RASSF1A inhibited the Wnt/β-catenin activity, decreased phosphorylation of Akt/glycogen synthase kinase-3-β (GSK3-β), and increased phosphorylation of mammalian sterile 20-like kinase 1 (MST1). Overexpression of RASSF1A downregulated the cyclin D1, c-Myc, and matrix metalloproteinase-7 (MMP-7) protein levels. RASSF1A functions as a tumor suppressor in osteosarcoma and exerts anti-cancer roles through regulating Akt/GSK-3-Wnt/β-catenin signaling.

Dihydroartemisinin inhibits the Raf/ERK/MEK and PI3K/AKT pathways in glioma cells

It has previously been reported that dihydroartemisinin (DHA) is an effective novel anticancer compound in a number of types of tumor cells. Previous studies have demonstrated the anticancer activity of DHA in gioma cells. However, its underlining mechanism remains unclear. In the present study, the anticancer activity of DHA was examined in the glioma cell lines BT325 and C6. Western blot analysis was also employed to determine the signaling pathway changes. It was demonstrated that DHA effectively inhibited cell growth and induced apoptosis in glioma cells. Moreover, western blot analysis indicated that DHA-induced apoptosis was accompanied by inactivation of the Raf/MEK/ERK and PI3K/AKT signaling pathways, in addition to the downregulation of anti-apoptotic proteins Mcl-1 and Bcl-2 expression levels.

Novel cancer chemotherapy hits by molecular topology: dual Akt and Beta-catenin inhibitors

Background and Purpose

Colorectal and prostate cancers are two of the most common types and cause of a high rate of deaths worldwide. Therefore, any strategy to stop or at least slacken the development and progression of malignant cells is an important therapeutic choice. The aim of the present work is the identification of novel cancer chemotherapy agents. Nowadays, many different drug discovery approaches are available, but this paper focuses on Molecular Topology, which has already demonstrated its extraordinary efficacy in this field, particularly in the identification of new hit and lead compounds against cancer. This methodology uses the graph theoretical formalism to numerically characterize molecular structures through the so called topological indices. Once obtained a specific framework, it allows the construction of complex mathematical models that can be used to predict physical, chemical or biological properties of compounds. In addition, Molecular Topology is highly efficient in selecting and designing new hit and lead drugs. According to the aforementioned, Molecular Topology has been applied here for the construction of specific Akt/mTOR and β-catenin inhibition mathematical models in order to identify and select novel antitumor agents.

Experimental Approach

Based on the results obtained by the selected mathematical models, six novel potential inhibitors of the Akt/mTOR and β-catenin pathways were identified. These compounds were then tested in vitro to confirm their biological activity.

Conclusion and Implications

Five of the selected compounds, CAS n° 256378-54-8 (Inhibitor n°1), 663203-38-1 (Inhibitor n°2), 247079-73-8 (Inhibitor n°3), 689769-86-6 (Inhibitor n°4) and 431925-096 (Inhibitor n°6) gave positive responses and resulted to be active for Akt/mTOR and/or β-catenin inhibition. This study confirms once again the Molecular Topology’s reliability and efficacy to find out novel drugs in the field of cancer.

Depletion of ALX1 causes inhibition of migration and induction of apoptosis in human osteosarcoma

Osteosarcoma is the most common primary malignant tumor in children and young adults, and the molecular regulation of the invasion of osteosarcoma (OS) remains unknown. In this study, we found that increased expression of ALX1 was associated with the progression of osteosarcoma and that ALX1 protein levels were significantly elevated in matched distant metastases. High ALX1 levels also predict shorter overall survival of osteosarcoma patients. We investigated the therapeutic potential of targeting ALX1 expression using the technique of RNA silencing via short hairpin RNA (shRNA). Synthetic shRNA duplexes against ALX1 were introduced to downregulate the expression of ALX1 in a highly malignant osteosarcoma cell line, U2OS. The results obtained indicated that shRNA targeting of ALX1 could lead to an efficient and specific inhibition of endogenous ALX1 activity. Furthermore, we found that depletion of ALX1 caused a dramatic cell cycle arrest, followed by massive apoptotic cell death, and eventually resulted in a significant decrease in migration and invasion of the osteosarcoma cell line studied.

Wnt pathway in osteosarcoma, from oncogenic to therapeutic

Osteosarcoma is the most common malignant bone tumor in children and adolescents. Although pathologic characteristics of this disease are clear and well established, much remains to be understood about this tumor, particularly at the molecular signaling level. Secreted signaling molecules of the Wnt family have been widely investigated and found to play a central role in controlling embryonic bone development, bone mass, and postnatal bone regeneration. A variety of studies also suggest that Wnt signaling pathway is closely associated with bone malignancies, including breast or prostate cancer induced bone metastasis, multiple myeloma, as well as osteosarcoma. Here, we provide an overview of the role of Wnt signaling pathway in osteosarcoma development and progression, highlighting the aberrant activation of Wnt pathway in this bone malignancy. We also discuss the potential therapeutic applications for the treatment of osteosarcoma targeting Wnt pathway.

Wnt/β-catenin pathway in bone cancers

The Wnt signaling pathway regulates some of the crucial aspects of cellular processes. The beta-catenin dependent Wnt signaling (Wnt/β-catenin) pathway controls the expression of key developmental genes, and acts as an intracellular signal transducer. The association of Wnt/β-catenin pathway is often reported with different cancers. In this study, we have reviewed the association of Wnt/β-catenin pathway with bone cancers, focusing on carcinogenesis and therapeutic aspects. Wnt/β-catenin pathway is a highly complex and unique signaling pathway, which has ability to regulate gene expression, cell invasion, migration, proliferation, and differentiation for the initiation and progression of bone cancers, especially osteosarcoma. Association of Wnt/β-catenin pathway with chondrosarcoma, Ewing's sarcoma and chondroma is also documented. Recently, targeting Wnt/β-catenin pathway has gained significant interests as a potential therapeutic application for the treatment of bone cancers. Small RNA technology to knockdown aberrant Wnt/β-catenin or inhibition of β-catenin expression by natural component has shown promising effects against bone cancers. Advances in understanding the mechanisms of Wnt signaling and new technologies have facilitated the discovery of agents that can target and regulate Wnt/β-catenin signaling pathway, and these may provide a basement for the innovative therapeutic approaches in the treatment of bone cancers.

A review of dihydroartemisinin as another gift from traditional Chinese medicine not only for malaria control but also for schistosomiasis control

Artemisinin, also known as qinghaosu, is a sesquiterpene lactone endoperoxide extracted from the plant Artemisia annua L, an herb employed in traditional Chinese medicine. Artemisinin and its two main derivatives artemether and artesunate have been shown to be effective against both malaria and schistosomiasis, and therefore, they were described by Liu et al (Parasitol Res 110:2071-2074, 2012b) as the gifts from traditional Chinese medicine not only for malaria control but also for schistosomiasis control. However, another artemisinin derivative dihydroartemisinin (DHA) cannot be neglected. Dihydroartemisinin, a derivative of artemisinin with the C-10 lactone group replaced by hemiacetal and the active metabolite of all artemisinin compounds, was firstly identified as an antimalarial agent, and the dihydroartemisinin-piperaquine combination has been recommended as a first-line treatment of uncomplicated Plasmodium falciparum malaria by the WHO. It has been recently found that administration of dihydroartemisinin at a single dose of 300 mg/kg 2 h or 3, 5, 7, 10, 14, 18, 21, 28, or 35 days post-infection reduces total worm burdens by 1.1-64.8% and female worm burden reductions by 11.9-90.5%, and the in vivo activity of dihydroartemisinin against S. japonicum is enhanced by the use of multiple doses. However, a combination of praziquantel and dihydroartemisinin appears no more effective against S. japonicum schistosomulum than treatment with dihydroartemisinin alone. In mice experimentally infected with S. mansoni, administration with dihydroartemisinin at a single dose of 300 mg/kg on days 1, 7, 14, 21, 28, 35, 42, 49, or 56 post-infection results in total worm burden reductions of 13.8-82.1% and female worm burden reductions of 13-82.8%, and a clear-cut dose-response relationship of dihydroartemisinin against the schistosomula and adult worms of S. mansoni is observed. In addition, dihydroartemisinin was found to cause damages to the reproductive system of female S. mansoni worms, reduce the oviposition of survival worms, and inhibit the formation of granulomas around tissue-trapped eggs. More interestingly, no reduced sensitivity to dihydroartemisinin is detected in praziquantel non-susceptible S. japonicum, which provides a new option for the treatment of S. japonicum and S. mansoni infections, notably in endemic foci with praziquantel resistance or insensitivity detected. It is therefore considered that dihydroartemisinin is another gift from the traditional Chinese medicine not only for malaria control but also for schistosomiasis control.

TIKI2 suppresses growth of osteosarcoma by targeting Wnt/β-catenin pathway

Osteosarcoma is the most bone-associated malignancy with high lethality. The current therapeutic strategy benefits little on the survival of patients. Studies have shown that aberrant activation of Wnt/β-catenin pathway is essential for the progression of osteosarcoma, implying that targeting this signaling may be an effective way of therapeutics. Recently, TIKI family has been identified as a new class of negative regulators for Wnt/β-catenin pathway. However, the implication of TIKIs with osteosarcoma has not been explored. Here, we constructed an adenoviral vector that expresses TIKI2 in osteosarcoma cells (Ad-TIKI2). TIKI2 expression was found to be reduced in osteosarcoma specimens and cell lines. In tested osteosarcoma cells, the activation of Wnt/β-catenin pathway was found to be inhibited by TIKI2 expression. Furthermore, the proliferation, colony formation ability, and invasion were all significantly suppressed in osteosarcoma cells infected with Ad-TIKI2. Finally, animal experiments further confirmed that TIKI2 restoration was able to inhibit the growth of osteosarcoma in vivo. Taken together, we provided evidence that reduced expression of TIKI family protein in osteosarcoma may participate in the progression of osteosarcoma and restoring its expression was able to impair the growth of osteosarcoma.