Dihydroartemisinin Inhibits the Proliferation of Esophageal Squamous Cell Carcinoma Partially by Targeting AKT1 and p70S6K

Artemisinin and Its Derivatives as Potential Anticancer Agents

Artemisinin is a natural sesquiterpene lactone obtained from the traditional Chinese medicinal herb Artemisia annua L. (qinghao). Artemisinin and its derivatives share an unusual endoperoxide bridge and are extensively used for malaria treatment worldwide. In addition to antimalarial activities, artemisinin and its derivatives have been reported to exhibit promising anticancer effects in recent decades. In this review, we focused on the research progress of artemisinin and its derivatives with potential anticancer activities. The pharmacological effects, potential mechanisms, and clinical trials in cancer therapy of artemisinin and its derivatives were discussed. This review may facilitate the future exploration of artemisinin and its derivatives as effective anticancer agents.

MCM8 promotes gastric cancer progression through RPS15A and predicts poor prognosis

BACKGROUND

Gastric cancer (GC) is the fourth leading cause of cancer-related death worldwide. Minichromsome maintenance proteins family member 8 (MCM8) assists DNA repair and DNA replication. MCM8 exerts tumor promotor function in multiple digestive system tumors. MCM8 is also considered as a potential cancer therapeutic target.

METHODS

Bioinformatics methods were used to analyze MCM8 expression and clinicopathological significance. MCM8 expression was detected by immunohistochemistry (IHC) staining and qRT-PCR. MCM8 functions in GC cell were explored by Celigo cell counting, colony formation, wound-healing, transwell, and annexin V-APC staining assays. The target of MCM8 was determined by human gene expression profile microarray. Human phospho-kinase array kit evaluated changes in key proteins after ribosomal protein S15A (RPS15A) knockdown. MCM8 functions were reassessed in xenograft mouse model. IHC detected related proteins expression in mouse tumor sections.

RESULTS

MCM8 was significantly upregulated and predicted poor prognosis in GC. High expression of MCM8 was positively correlated with lymph node positive (p < 0.001), grade (p < 0.05), AJCC Stage (p < 0.001), pathologic T (p < 0.01), and pathologic N (p < 0.001). MCM8 knockdown inhibited proliferation, migration, and invasion while promoting apoptosis. RPS15A expression decreased significantly after MCM8 knockdown. It was also the only candidate target, which ranked among the top 10 downregulated differentially expressed genes (DEGs) in sh-MCM8 group. RPS15A was identified as the target of MCM8 in GC. MCM8/RPS15A promoted phosphorylation of P38α, LYN, and p70S6K. Moreover, MCM8 knockdown inhibited tumor growth, RPS15A expression, and phosphorylation of P38α, LYN, and p70S6K in vivo.

CONCLUSIONS

MCM8 is an oncogene and predicts poor prognosis in GC. MCM8/RPS15A facilitates GC progression.

Target discovery of bioactive natural products with native-compound-coupled CNBr-activated Sepharose 4B beads (NCCB): Applications, mechanisms and outlooks

Natural products (NPs) represent a treasure trove for drug discovery and development due to their chemical structural diversity and a broad spectrum of biological activities. Uncovering the biological targets and understanding their molecular mechanism of actions are crucial steps in the development of clinical therapeutics. However, the structural complexity of NPs and intricate nature of biological system present formidable challenges in target identification of NPs. Although significant advances have been made in the development of new chemical tools, these methods often require high levels of synthetic skills for preparing chemical probes. This can be costly and time-consuming relaying on operationally complicated procedures and instruments. In recent efforts, we and others have successfully developed an operationally simple and practical chemical tool known as native-compound-coupled CNBr-activated Sepharose 4B beads (NCCB) for NP target identification. In this approach, a native compound readily reacts with commercial CNBr-activated Sepharose 4B beads with a process that is easily performed in any biology laboratory. Based on NCCB, our group has identified the direct targets of more than 60 NPs. In this review, we will elucidate the application scopes, including flavonoids, quinones, terpenoids and others, characteristics, chemical mechanisms, procedures, advantages, disadvantages, and future directions of NCCB in specific target discovery.

Daurisoline suppresses esophageal squamous cell carcinoma growth in vitro and in vivo by targeting MEK1/2 kinase

Esophageal squamous cell carcinoma (ESCC) accounts for 90% of esophageal cancers and has a high mortality rate worldwide. The 5-year survival rate of ESCC patients in developing countries is <20%. Hence, there is an urgent need for developing new and effective treatments that are based on newly-discovered emerging molecules and pathways to prevent ESCC occurrence and recurrence. We investigated the effects of Daurisoline, a bis-benzylisoquinoline alkaloid extracted from the rhizome of menisperum dauricum, on ESCC cell proliferation and elucidated the molecular mechanisms underlying its functions. To explore the effects of Daurisoline on ESCC growth in vitro and in vivo, cell proliferation assays and anchorage-independent growth assays were performed and a patient-derived xenograft (PDX) model was established. Subsequently, phosphoproteomics, molecular docking analysis, pull down assays, mutation experiments and in vitro kinase assay were performed to explore the mechanism of Daurisoline's function on ESCC. Daurisoline inhibited ESCC proliferation in vitro and reduced ESCC PDX exnograft growth in vivo by reducing ERK1/2 phosphorylation. Furthermore, it directly bound to MEK1 (at Asn78 and Lys97) and MEK2 (at Asp194 and Asp212) kinases to inactivate the ERK1/2 signaling pathway. Our results suggest that Daurisoline is a dual inhibitor of MEK1 and MEK2 and suppresses ESCC growth both in vitro and in vivo by inactivating the ERK1/2 signaling pathway. This is first report on the use of MEK inhibitor for ESCC and highlights its potential applications for ESCC treatment and prevention.

Network pharmacology- and molecular docking-based approaches to unveil the pharmacological mechanisms of dihydroartemisinin against esophageal carcinoma

Objective: Dihydroartemisinin (DHA) is an active metabolite of artemisinin and its derivatives, which is a potent drug extensively applied in clinical treatment of malaria. The antitumor properties of DHA have received increasing attention. However, there is no systematic summary on the pharmacological mechanisms of DHA against esophageal carcinoma (ESCA). The present study implemented network pharmacology- and molecular docking-based approaches to unveil the pharmacological mechanisms of DHA against ESCA. Methods: DHA targets were accessed through integrating the SwissTargetPrediction, HERB, as well as BATMAN-TCM platforms. In TCGA-ESCA dataset, genes with differential expression were screened between 161 ESCA and 11 normal tissue specimens. DHA targets against ESCA were obtained through intersection. Their biological significance was evaluated with functional enrichment analysis. A prognostic signature was established via uni- and multivariate cox regression analyses. DHA-target interactions were predicted via molecular docking. Molecular dynamics simulation was implemented to examine the stability of DHA binding to potential targets. Results: The study predicted 160 DHA targets as well as 821 genes with differential expression in ESCA. Afterwards, 16 DHA targets against ESCA were obtained, which remarkably correlated to cell cycle progression. The ADORA2B- and AURKA-based prognostic signature exhibited the reliability and independency in survival prediction. The stable docking of DHA-ADORA2B and DHA-AURKA was confirmed. Conclusion: Collectively, this study systematically revealed the basis and mechanism of DHA against ESCA through targeting multi-target and multi-pathway mechanisms, and thus offered theoretical and scientific basis for the clinical application of DHA.

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

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

Human Telomerase Reverse Transcriptase as a Therapeutic Target of Dihydroartemisinin for Esophageal Squamous Cancer

Objective: To elucidate the oncogenic role of human telomerase reverse transcriptase (hTERT) in esophageal squamous cancer and unravel the therapeutic role and molecular mechanism of dihydroartemisinin (DHA) by targeting hTERT. Methods: The expression of hTERT in esophageal squamous cancer and the patients prognosis were analyzed by bioinformatic analysis from TCGA database, and further validated with esophageal squamous cancer tissues in our cohort. The Cell Counting Kit-8 (CCK8) and colony formation assay were used to evaluate the proliferation of esophageal squamous cancer cell lines (Eca109, KYSE150, and TE1) after hTERT overexpression or treated with indicated concentrations of DHA. Transwell migration assay and scratch assay were employed to determine the migration abilities of cancer cells. Fluorescence microscopy and flow cytometry were conducted to measure the intracellular reactive oxygen species (ROS) levels in cancer cells after treated with DHA. Moreover, RT-PCR and Western blot were performed to test the alteration of associated genes on mRNA and protein level in DHA treated esophageal squamous cancer cell lines, respectively. Furthermore, tumor-bearing nude mice were employed to evaluate the anticancer effect of DHA in vivo. Results: We found that hTERT was significantly upregulated in esophageal squamous cancer both from TCGA database and our cohort also. Overexpression of hTERT evidently promoted the proliferation and migration of esophageal squamous cancer cells in vitro. Moreover, DHA could significantly inhibit the proliferation and migration of esophageal cancer cell lines Eca109, KYSE150, and TE1 in vitro, and significantly down-regulate the expression of hTERT on both mRNA and protein level in a time- and dose-dependent manner as well. Further studies showed that DHA could induce intracellular ROS production in esophageal cancer cells and down-regulate SP1 expression, a transcription factor that bound to the promoter region of hTERT gene. Moreover, overexpression of SP1 evidently promoted the proliferation and migration of Eca109 and TE1 cells. Intriguingly, rescue experiments showed that inhibiting ROS by NAC alleviated the downregulation of SP1 and hTERT in cells treated with DHA. Furthermore, overexpression of SP1 or hTERT could attenuate the inhibition effect of DHA on the proliferation and migration of Eca109 cells. In tumor-bearing nude mice model, DHA significantly inhibited the growth of esophageal squamous cancer xenografts, and downregulated the expression of SP1 and hTERT protein, while no side effects were observed from heart, kidney, liver, and lung tissues by HE stain. Conclusion: hTERT plays an oncogenic role in esophageal squamous cancer and might be a therapeutic target of DHA through regulating ROS/SP1 pathway.

Chemical Constituents and their Anti-Tumor Mechanism of Plants from Artemisia

BACKGROUND

At present, chemotherapy is still the main treatment method for cancer, but its side effects and multidrug resistance limit the therapeutic effect seriously. Now the screening of anti-tumor drugs with higher efficiency and lower toxicity from natural products is one of the important research directions for oncotherapy. Artemisia has a variety of anti-tumor constituents, which can exert its anti-tumor effect by inducing tumor cell apoptosis, inhibiting tumor angiogenesis, arresting cell cycle, accelerating iron ion-mediated oxidative damage, etc. Objective: This paper will provide a focused, up-to-date and comprehensive overview of the anti-tumor active constituents and their mechanisms of plants in Artemisia.

METHOD

The relevant information about Artemisia and its bioactive components comes from scientific databases (such as PubMed, Web of Science, Science Direct).

RESULTS

Here we have discussed the present situation and mechanism of bioactive components of Artemisia in anti-tumor. The application prospect of active components of Artemisia in cancer prevention and treatment was investigated.

CONCLUSION

The information summarized in this review may provide new ideas for the follow-up treatment of cancer and contribute to the development of new, effective, multi-side effects and fewer side effects of antineoplastic drugs.

Dihydroartemisinin Inhibits mTORC1 Signaling by Activating the AMPK Pathway in Rhabdomyosarcoma Tumor Cells

Dihydroartemisinin (DHA), an anti-malarial drug, has been shown to possess potent anticancer activity, partly by inhibiting the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) signaling. However, how DHA inhibits mTORC1 is still unknown. Here, using rhabdomyosarcoma (RMS) as a model, we found that DHA reduced cell proliferation and viability in RMS cells, but not those in normal cells, which was associated with inhibition of mTORC1. Mechanistically, DHA did not bind to mTOR or FK506 binding protein 12 (FKBP12). In addition, DHA neither inhibited insulin-like growth factor-1 receptor (IGF-1R), phosphoinositide 3-kinase (PI3K), and extracellular signal-regulated kinase ½ (Erk1/2), nor activated phosphatase and tensin homolog (PTEN) in the cells. Rather, DHA activated AMP-activated protein kinase (AMPK). Pharmacological inhibition of AMPK, ectopic expression dominant negative or kinase-dead AMPK, or knockdown of AMPKα attenuated the inhibitory effect of DHA on mTORC1 in the cells. Additionally, DHA was able to induce dissociation of regulatory-associated protein of mTOR (raptor) from mTOR and inhibit mTORC1 activity. Moreover, treatment with artesunate, a prodrug of DHA, dose-dependently inhibited tumor growth and concurrently activated AMPK and suppressed mTORC1 in RMS xenografts. The results indicated that DHA inhibits mTORC1 by activating AMPK in tumor cells. Our finding supports that DHA or artesunate has a great potential to be repositioned for treatment of RMS.