Dimeric oxyberberine CT4-1 targets LINC02331 to induce cytotoxicity and inhibit chemoresistance via suppressing Wnt/β-catenin signaling in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a type of cancer characterized by high recurrence rates. Overcoming chemoresistance can reduce HCC recurrence and improve patients' prognosis. This work aimed to identify HCC chemoresistance-associated long non-coding RNA (lncRNA) and find an effective drug targeting the identified lncRNA for ameliorating the chemoresistance. In this investigation, bioinformatics analysis based on The Cancer Genome Atlas revealed a new chemoresistance index and suggested LINC02331 as an HCC chemoresistance and patients' prognosis-associated lncRNA that served as an independent prognostic indicator. Moreover, LINC02331 promoted DNA damage repair, DNA replication, and epithelial-mesenchymal transition as well as attenuated cell cycle arrest and apoptosis through regulating Wnt/β-catenin signaling, thus stimulating HCC resistance to cisplatin cytotoxicity, proliferation, and metastasis. Interestingly, we developed a novel oxidative coupling approach to synthesize a dimeric oxyberberine CT4-1, which exerted superior anti-HCC activities without obvious side effects measured by in vivo mice model and could downregulate LINC02331 mice model and could downregulate LINC02331 to mitigate LINC02331-induced HCC progression by suppressing Wnt/β-catenin signaling. RNA sequencing analyses verified the involvement of CT4-1-affected differential expression genes in dysregulated pathways and processes, including Wnt, DNA damage repair, cell cycle, DNA replication, apoptosis, and cell adhesion molecules. Furthermore, CT4-1 was demonstrated to be an effective cytotoxic drug in ameliorating HCC patients' prognosis with a prediction model constructed based on RNA-sequencing data from CT4-1-treated cancer cells and public cancer database. In summary, HCC chemoresistance-associated LINC02331 independently predicted poor patients' prognosis and enhanced HCC progression by promoting resistance to cisplatin cytotoxicity, proliferation, and metastasis. Targeting LINC02331 by the dimeric oxyberberine CT4-1 that exhibited synergistic cytotoxicity with cisplatin could alleviate HCC progression and improve patients' prognosis. Our study identified LINC02331 as an alternative target and suggested CT4-1 as an effective cytotoxic drug in HCC treatment.

Natural Products as Anticancer Agents: Current Status and Future Perspectives

Natural products have been an invaluable and useful source of anticancer agents over the years. Several compounds have been synthesized from natural products by modifying their structures or by using naturally occurring compounds as building blocks in the synthesis of these compounds for various purposes in different fields, such as biology, medicine, and engineering. Multiple modern and costly treatments have been applied to combat cancer and limit its lethality, but the results are not significantly refreshing. Natural products, which are a significant source of new therapeutic drugs, are currently being investigated as potential cytotoxic agents and have shown a positive trend in preclinical research and have prompted numerous innovative strategies in order to combat cancer and expedite the clinical research. Natural products are becoming increasingly important for drug discovery due to their high molecular diversity and novel biofunctionality. Furthermore, natural products can provide superior efficacy and safety due to their unique molecular properties. The objective of the current review is to provide an overview of the emergence of natural products for the treatment and prevention of cancer, such as chemosensitizers, immunotherapeutics, combinatorial therapies with other anticancer drugs, novel formulations of natural products, and the molecular mechanisms underlying their anticancer properties.

Xanthotoxol suppresses non-small cell lung cancer progression and might improve patients' prognosis

BACKGROUND

Developing novel and effective drugs with less toxicity is urgent for non-small cell lung cancer (NSCLC) therapy. Xanthotoxol (Xan) is the major natural component of the medical plant Angelica dahurica with potential anti-cancer activities.

PURPOSE

In this study, we aimed to demonstrate the effect and underlying mechanism of Xan in NSCLC and evaluate the effectiveness of Xan in NSCLC patients.

METHODS

CCK8, colony formation, EdU, flow cytometry, and transwell assays were carried out to investigate the anti-NSCLC activity of Xan in vitro. In addition, the xenograft mouse model was established to evaluate the anti-NSCLC effect of Xan in vivo. Moreover, bioinformatics analysis was performed to establish a prediction model based on RNA sequencing data. Furthermore, Western blot was used to detect the expression of proteins regulated by Xan.

RESULTS

Xan inhibited the cell viability, colony formation capacity, DNA replication, cell cycle transition, migration and invasion, as well as inducing apoptosis of NSCLC cells. In addition, Xan suppressed NSCLC xenograft growth in vivo without obvious toxicity. Interestingly, bioinformatics analyses based on the RNA sequencing data indicated that Xan exerted inhibitory effects on NSCLC cells by down-regulating signals contributing to NSCLC progression and demonstrated that Xan was effective in ameliorating the prognosis of NSCLC patients with a new proposed prediction model. Moreover, Xan was shown to regulate cell cycle arrest, apoptosis, and epithelial-mesenchymal transition (EMT)-associated genes through downregulating PI3K-AKT signaling, thus suppressing NSCLC proliferation and metastasis.

CONCLUSIONS

Taken together, our work proved that Xan induced cell cycle arrest, facilitated apoptosis, and inhibited EMT processes through downregulating the PI3K-AKT pathway to suppress NSCLC progress. Moreover, we also proposed a new model for evaluating Xan as a novel and effective drug in NSCLC treatments.

Potential roles and molecular mechanisms of phytochemicals against cancer

Increasing evidence has been reported regarding phytochemicals, plant secondary metabolites, having therapeutic functions against numerous human diseases. Recently, phytochemicals (flavonoids, polyphenols, terpenoids, alkaloids, saponins, coumarins and so on) have shown promising anti-cancer efficacy with their distinct advantages of high efficiency and low toxicity. They regulate programmed cell death (apoptosis, pyroptosis, and autophagy), migration and senescence-related signaling pathways of cancer via the modulation of reactive oxygen species (ROS), mitogen activated protein kinase (MAPK) pathway, deleted in liver cancer 1 (DLC1), nuclear factor κ light-chain-enhancer of activated B cell (NF-κB) pathways and glycolytic enzymes. Here, we review the molecular mechanisms by which phytochemicals prevent the development of cancer. Furthermore, phytochemicals combined with chemotherapeutic agents could target the crosstalk among multiple signal cascades to block chemoresistance and attenuate carcinogenic properties, and can be considered as a novel and potential therapeutic strategy. Our review highlights that the mechanisms and promising applications are required to be understood to decisively establish the anti-cancer efficacy of natural phytochemicals.

Escape From Cisplatin-Induced Senescence of Hypoxic Lung Cancer Cells Can Be Overcome by Hydroxychloroquine

Chemotherapy is the commonly used treatment for advanced lung cancer. However, it produces side effects such as the development of chemoresistance. A possible responsible mechanism may be therapy-induced senescence (TIS). TIS cells display increased senescence-associated β-galactosidase (SA-β-gal) activity and irreversible growth arrest. However, recent data suggest that TIS cells can reactivate their proliferative potential and lead to cancer recurrence. Our previous study indicated that reactivation of proliferation by TIS cells might be related with autophagy modulation. However, exact relationship between both processes required further studies. Therefore, the aim of our study was to investigate the role of autophagy in the senescence-related chemoresistance of lung cancer cells. For this purpose, human and murine lung cancer cells were treated with two commonly used chemotherapeutics: cisplatin (CIS), which forms DNA adducts or docetaxel (DOC), a microtubule poison. Hypoxia, often overlooked in experimental settings, has been implicated as a mechanism responsible for a significant change in the response to treatment. Thus, cells were cultured under normoxic (~19% O₂) or hypoxic (1% O₂) conditions. Herein, we show that hypoxia increases resistance to CIS. Lung cancer cells cultured under hypoxic conditions escaped from CIS-induced senescence, displayed reduced SA-β-gal activity and a decreased percentage of cells in the G2/M phase of the cell cycle. In turn, hypoxia increased the proliferation of lung cancer cells and the proportion of cells proceeding to the G0/G1 phase. Further molecular analyses demonstrated that hypoxia inhibited the prosenescent p53/p21 signaling pathway and induced epithelial to mesenchymal transition in CIS-treated cancer cells. In cells treated with DOC, such effects were not observed. Of importance, pharmacological autophagy inhibitor, hydroxychloroquine (HCQ) was capable of overcoming short-term CIS-induced resistance of lung cancer cells in hypoxic conditions. Altogether, our data demonstrated that hypoxia favors cancer cell escape from CIS-induced senescence, what could be overcome by inhibition of autophagy with HCQ. Therefore, we propose that HCQ might be used to interfere with the ability of senescent cancer cells to repopulate following exposure to DNA-damaging agents. This effect, however, needs to be tested in a long-term perspective for preclinical and clinical applications.

Comprehensive Analysis of Inhibitor of Apoptosis Protein Expression and Prognostic Significance in Non-Small Cell Lung Cancer

Inhibitors of apoptosis proteins (IAPs) have been associated with tumor development and progression by affecting apoptosis through cell death signaling pathways. To date, eight IAPs (BIRC1-8) have been identified in mammalian cells. However, the role of IAPs in non-small cell lung cancer (NSCLC) development and progression has not been explored in depth. In this study, we used public datasets and bioinformatics tools to compare the expression, prognostic significance, and function of IAPs in NSCLC and its subtypes. Expression of IAPs in cancer and normal tissues and at different stages of NSCLC was compared with gene expression profiling interactive analysis, and their prognostic significance was analyzed with the Kaplan-Meier Plotter database. The correlations among IAPs were analyzed with the STRING database and SPSS19.0. Functional annotation of IAPs was analyzed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment on the basis of the DAVID tool. Among patients with lung adenocarcinoma (LUAD), the expression level of BIRC5 was higher than that in normal samples, and the expression of BIRC1 and BIRC5 significantly varied in different stages. Moreover, the BIRC1-3 and BIRC5 mRNA levels were associated with overall survival (OS), and the BIRC1-2 and BIRC5-6 mRNA levels were associated with progression-free survival (PFS). Among patients with lung squamous cell carcinoma (LUSC), the expression level of BIRC1 was lower and that of BIRC5 was higher than those in normal tissues, and BIRC5 expression significantly varied in different stages. BIRC1 expression was associated with OS, whereas BIRC2 and BIRC6 expression was associated with PFS. Enrichment analysis showed that most IAPs are associated with ubiquitin- and apoptosis-related pathways. Collectively, this study suggests BIRC5 as a potential diagnostic and staging marker, BIRC1 as a potential marker of OS, and BIRC2 and BIRC6 as potential PFS markers for patients with NSCLC. These highlight new targets for the early detection, treatment, and management of NSCLC.

Demethyleneberberine induces cell cycle arrest and cellular senescence of NSCLC cells via c-Myc/HIF-1α pathway

BACKGROUND

Demethyleneberberine (DMB) is a natural active component of medicinal plant Cortex phellodendri chinensis with favorable bioactivity. However, the role of DMB in suppressing non-small cell lung cancer (NSCLC) remains unknown.

PURPOSE

In this study, we aimed to examine the effect and underlying mechanism of DMB in suppressing NSCLC.

METHODS

CCK8 assay and colony formation assay were utilized to assess the efficiency of DMB on the viability and colony formation capacity of NSCLC cells. Flow cytometry and β-Galactosidase Staining Kit were utilized to determine the efficiency of DMB on the cell cycle and cellular senescence of NSCLC cells. RT-qPCR and Western blot were used to detect the effect of DMB on cell cycle and cellular senescence related gene and protein expression of NSCLC cells. In vivo tumor model was established to evaluate the anti NSCLC effect of DMB. In addition, RNA-seq analysis was performed to detect the differential gene expression after DMB treatments.

RESULTS

In this study, we revealed that DMB exhibits efficient inhibitory effect on NSCLC cell proliferation and tumor xenografts growth in vivo. We also demonstrated that DMB could inhibit cell migration by suppressing epithelial-mesenchymal transition (EMT) and trigger cell cycle arrest by down-regulating the expression of cell cycle related genes in NSCLC cells. In addition, DMB treatment efficiently induces cellular senescence of NSCLC cells. From the RNA-seq analysis, we found that DMB accelerates senescence through suppressing HIF-1α expression, which was further elucidated by overexpressing HIF-1α in NSCLC to reduce the inhibitory effect of DMB. Furthermore, we also revealed that DMB decreases the expression of c-Myc, an up-stream protein of HIF-1α.

CONCLUSIONS

Taken together, we first report that DMB inhibits NSCLC progress through inducing cell cycle arrest and triggering cellular senescence by downregulating c-Myc/HIF-1α pathway.

Impacts of NF1 Gene Mutations and Genetic Modifiers in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a tumor predisposition genetic disorder that directly affects more than 1 in 3,000 individuals worldwide. It results from mutations of the NF1 gene and shows almost complete penetrance. NF1 patients show high phenotypic variabilities, including cafe-au-lait macules, freckling, or other neoplastic or non-neoplastic features. Understanding the underlying mechanisms of the diversities of clinical symptoms might contribute to the development of personalized healthcare for NF1 patients. Currently, studies have shown that the different types of mutations in the NF1 gene might correlate with this phenomenon. In addition, genetic modifiers are responsible for the different clinical features. In this review, we summarize different genetic mutations of the NF1 gene and related genetic modifiers. More importantly, we focus on the genotype–phenotype correlation. This review suggests a novel aspect to explain the underlying mechanisms of phenotypic heterogeneity of NF1 and provides suggestions for possible novel therapeutic targets to prevent or delay the onset and development of different manifestations of NF1.

Perspectives and controversies regarding the use of natural products for the treatment of lung cancer

Lung cancer is the leading cause of cancer‐related mortality both in men and women and accounts for 18.4% of all cancer‐related deaths. Although advanced therapy methods have been developed, the prognosis of lung cancer patients remains extremely poor. Over the past few decades, clinicians and researchers have found that chemical compounds extracted from natural products may be useful for treating lung cancer. Drug formulations derived from natural compounds, such as paclitaxel, doxorubicin, and camptothecin, have been successfully used as chemotherapeutics for lung cancer. In recent years, hundreds of new natural compounds that can be used to treat lung cancer have been found through basic and sub‐clinical research. However, there has not been a corresponding increase in the number of drugs that have been used in a clinical setting. The probable reasons may include low solubility, limited absorption, unfavorable metabolism, and severe side effects. In this review, we present a summary of the natural compounds that have been proven to be effective for the treatment of lung cancer, as well as an understanding of the mechanisms underlying their pharmacological effects. We have also highlighted current controversies and have attempted to provide solutions for the clinical translation of these compounds.

Uncovering the Anti-Lung-Cancer Mechanisms of the Herbal Drug FDY2004 by Network Pharmacology

With growing evidence on the therapeutic efficacy and safety of herbal drugs, there has been a substantial increase in their application in the lung cancer treatment. Meanwhile, their action mechanisms at the system level have not been comprehensively uncovered. To this end, we employed a network pharmacology methodology to elucidate the systematic action mechanisms of FDY2004, an anticancer herbal drug composed of Moutan Radicis Cortex, Persicae Semen, and Rhei Radix et Rhizoma, in lung cancer treatment. By evaluating the pharmacokinetic properties of the chemical compounds present in FDY2004 using herbal medicine-associated databases, we identified its 29 active chemical components interacting with 141 lung cancer-associated therapeutic targets in humans. The functional enrichment analysis of the lung cancer-related targets of FDY2004 revealed the enriched Gene Ontology terms, involving the regulation of cell proliferation and growth, cell survival and death, and oxidative stress responses. Moreover, we identified key FDY2004-targeted oncogenic and tumor-suppressive pathways associated with lung cancer, including the phosphatidylinositol 3-kinase-Akt, mitogen-activated protein kinase, tumor necrosis factor, Ras, focal adhesion, and hypoxia-inducible factor-1 signaling pathways. Overall, our study provides novel evidence and basis for research on the comprehensive anticancer mechanisms of herbal medicines in lung cancer treatment.

Leaf Extract of Nerium oleander L. Inhibits Cell Proliferation, Migration and Arrest of Cell Cycle at G2/M Phase in HeLa Cervical Cancer Cell

BACKGROUND

Cervical cancer is one of the most common gynaecological malignant tumors reported in women. Although a number of early screening and treatment options are available, mortality due to cervical cancer remains high. Nerium oleander L. is a potential medicinal plant that possesses a wide spectrum of pharmacological and physiological activities including anticancer activities.

OBJECTIVE

This study aims to evaluate the antiproliferative activity, inhibition of cell migration and cell cycle arrest by the chloroform extract of leaves of Nerium Oleander L. in HeLa cervical cancer cells. The chloroform extract of Catharanthus roseus which contains anti-cancer compounds, Vinblastin and Vincristin, was used as a positive control for this study.

METHODS

The chloroform extracts of Nerium oleander L. and Catharanthus roseus were prepared using the standard protocol. The cytotoxic effects were studied by MTT assay. Cell migration was studied by in vitro scratch assay. Analysis of the cell cycle was carried out by Propidium iodide staining and Flow Cytometry. The expression level of various proteins was evaluated by immunocytochemistry.

RESULTS

In this study, we showed that the leaf extract of Nerium oleander inhibited the growth of HeLa cervical cancer cells in culture and inhibited cell migration. Besides, it arrested the cell cycle at the G2/M phase. The Epidermal Growth Factor Receptor (EGFR) expression and phosphorylated p-Rb (Ser 780) level were significantly downregulated by leaf extract of Nerium oleander.

CONCLUSION

The extract of Nerium oleander L. contains potential bioactive compounds that inhibit HeLa cell proliferation, cell migration and arrest cell cycle at the G₂/M phase.

Artemisinins as Anticancer Drugs: Novel Therapeutic Approaches, Molecular Mechanisms, and Clinical Trials

Artemisinin and its derivatives have shown broad-spectrum antitumor activities in vitro and in vivo. Furthermore, outcomes from a limited number of clinical trials provide encouraging evidence for their excellent antitumor activities. However, some problems such as poor solubility, toxicity and controversial mechanisms of action hamper their use as effective antitumor agents in the clinic. In order to accelerate the use of ARTs in the clinic, researchers have recently developed novel therapeutic approaches including developing novel derivatives, manufacturing novel nano-formulations, and combining ARTs with other drugs for cancer therapy. The related mechanisms of action were explored. This review describes ARTs used to induce non-apoptotic cell death containing oncosis, autophagy, and ferroptosis. Moreover, it highlights the ARTs-caused effects on cancer metabolism, immunosuppression and cancer stem cells and discusses clinical trials of ARTs used to treat cancer. The review provides additional insight into the molecular mechanism of action of ARTs and their considerable clinical potential.

Cellular senescence and cancer: Focusing on traditional Chinese medicine and natural products

Cancer is the principal cause of death and a dominant public health problem which seriously threatening human life. Among various ways to treat cancer, traditional Chinese medicine (TCM) and natural products have outstanding anti‐cancer effects with their unique advantages of high efficiency and minimal side effects. Cell senescence is a physiological process of cell growth stagnation triggered by stress, which is an important line of defence against tumour development. In recent years, active ingredients of TCM and natural products, as an interesting research hotspot, can induce cell senescence to suppress the occurrence and development of tumours, by inhibiting telomerase activity, triggering DNA damage, inducing SASP, and activating or inactivating oncogenes. In this paper, the recent research progress on the main compounds derived from TCM and natural products that play anti‐cancer roles by inducing cell senescence is systematically reviewed, aiming to provide a reference for the clinical treatment of pro‐senescent cancer.

CT1-3, a novel magnolol-sulforaphane hybrid suppresses tumorigenesis through inducing mitochondria-mediated apoptosis and inhibiting epithelial mesenchymal transition

Chemotherapy is recognized as one of the indispensable treatment for solid tumors. However, the emergent drug resistance and undesirable side effects have become a substantial challenge and the bottleneck of cancer chemotherapy. Magnolol (MAG) is a natural polyphenol with various bioactivities. Sulforaphane (SFN) is identified as one of the most effective naturally occurring anticancer agents. In this study, we successfully synthesized the magnolol-sulforaphane (MAG-SFN) hybrid CT1-3, showcasing more efficient anticancer activity than its lead compounds MAG and SFN with IC₅₀ values ranging from 5.10 to 14.06 μM in multiple cancer cells. We also demonstrated that CT1-3 elicited a strong antitumor effect in vivo but has no hepatic and renal toxicity. Furthermore, we found out CT1-3 treatment resulted in reduction of Bcl-2 and XIAP levels, in addition to increase of phospho-JNK and Bax levels, leading to mitochondria-mediated apoptosis in human cancer cells. Moreover, we revealed that CT1-3 could reduce the capacity of migration and invasion of human cancer cells via regulating the E-cadherin/Snail axis. Taken together, we provided strong evidences that the first example of MAG-SFN hybrid CT1-3 is a promising anticancer drug candidate without apparent adverse effects, which suppresses tumorigenesis partly through inducing mitochondria-mediated apoptosis and inhibiting epithelial mesenchymal transition (EMT).

Berberine chloride suppresses non-small cell lung cancer by deregulating Sin3A/TOP2B pathway in vitro and in vivo

PURPOSE

Berberine chloride (BBC) is a well-known plant isoquinoline alkaloid derived from Berberis aristata. In this study, we aim to explore the effect of BBC on non-small cell lung cancer (NSCLC), and further expound the underlying mechanism of BBC induces NSCLC cell death in vitro and in vivo.

METHODS

CCK-8 assay and colony formation assay were used to test the viability and colony formation ability of NSCLC cells. Apoptosis analysis was used to analyze the apoptotic cells. siRNAs were utilized to disturb the expression of Sin3A. qPCR and Western blot analysis were employed to determine mRNA and protein levels of related genes and proteins. Tumor xenografts model was used for in vivo detection.

RESULTS

BBC inhibited the proliferation and colony formation of human NSCLC cells in a dose- and time-dependent manner. In addition, BBC induced DNA double-stranded breaks (DSBs) through downregulating TOP2B level, leading to apoptosis in human NSCLC cells. The Chip-seq data of A549 cells obtained from the ENCODE consortium indicate that Sin3A binds on the promoters of TOP2B. Knockdown of Sin3A led to downregulation of TOP2B in human NSCLC cells. Furthermore, BBC decreased Sin3A expression and shortened the half-life of Sin3A, results in downregulation of TOP2B in human NSCLC cells.

CONCLUSION

In this study, we demonstrated a new mechanism that BBC suppresses human NSCLC by deregulating Sin3A/TOP2B pathway, leading to DNA damage and apoptosis in human NSCLC in vitro and in vivo.

CuS-NiS2 nanomaterials for MRI guided phototherapy of gastric carcinoma via triggering mitochondria-mediated apoptosis and MLKL/CAPG-mediated necroptosis

Gastric carcinoma is one of the most lethal malignant tumors. As part of our long-term efforts on seeking effective diagnosis and therapeutic strategies of gastric cancer, we present herein novel ternary copper-based chalcogenide nanoplatform CuS-NiS₂ nanomaterials with outstanding photothermal (PT)/photodynamic (PD) property that could effectively suppress human gastric cancer in vitro and in vivo without obvious side effects. We revealed that CuS-NiS₂ induced reactive oxygen species (ROS) generation, leading to apoptosis through Bcl-2/Bax pathway of human gastric cancer cells under 808 nm near-infrared (NIR) irradiation. In addition, we also confirmed that the combination of CuS-NiS₂ and 808 nm NIR laser treatment triggered necroptosis by regulating the novel pathway MLKL/CAPG of human gastric cancer cells. Moreover, the CuS-NiS₂ exhibited excellent contrast enhancement according to magnetic resonance imaging (MRI). Taken together, we reported new ternary copper-based chalcogenide nanomaterials CuS-NiS₂, which could be successfully applied for MRI-guided PT/PD therapy of gastric carcinoma through mitochondria-mediated apoptosis and MLKL/CAPG-mediated necroptosis.

CT2-3, a novel magnolol analogue suppresses NSCLC cells through triggering cell cycle arrest and apoptosis

Magnolol, a major bioactive component found in Magnolia officinalis with anti-inflammation and anti-oxidation activities as well as minimized cytotoxic effects. Although magnolol has a wide range of clinical applications, the anti-tumor activity of magnolol is not efficient. Herein, we reported the synthesis and anti-cancer activities of three novel magnolol analogues CT2-1, CT2-2, CT2-3, among which CT2-3 revealed more efficient anti-non-small cell lung cancer (NSCLC) activity than magnolol. Our data showed that CT2-3 could significantly inhibit the proliferation of human NSCLC cells in a dose-dependent manner. In addition, we revealed CT2-3 could induce cell cycle arrest through down-regulating mRNA expression of CDK4, CDK6 and cyclin D1. Moreover, we verified that CT2-3 could cause ROS generation, leading to apoptosis of human NSCLC cells. Further more, we also provided strong evidences that CT2-3 down-regulates the expression of c-Myc and topoisomerases, and contributes to the apoptosis of human NSCLC cells. Taken together, the current study is the first to report a promising new chemotherapeutic drug candidate CT2-3 that can efficiently eliminate human NSCLC cells through triggering cell cycle arrest as well as ROS-mediated and c-Myc/topoisomerases-mediated apoptosis.

Artemisinin sensitizes tumor cells to NK cell-mediated cytolysis

The antimalarial drug Artemisinin has been reported to possess direct anti-tumor effects on various types of tumor cells. However, its anti-tumor potential has not been fully revealed, and its effects on tumor susceptibility to immune surveillance by the host are still unknown. Natural killer (NK) cells are the first line in tumor surveillance by the host, and have been recognized as a promising target for tumor immunotherapy. Here, we reported that Artemisinin sensitized tumor cells to NK cell cytolysis. Both human K562 and Raji tumor cells, and mouse YAC-1 tumor cells were more susceptible to human or mouse NK cell cytolysis in vitro after Artemisinin pretreatment. Conjugation formation between tumor cells and NK cells was increased after pretreatment with Artemisinin. Such effects on tumor cells by Artemisinin might not be the results of tumor recognition by NK cells, since major ligands of NK cell surface receptors were not affected. Mechanistically, although Artemisinin didn't induce tumor cell apoptosis, Artemisinin enriched apoptosis-related gene sets in these tumor cells, which might predispose tumor cells to apoptosis upon NK cell cytolysis. Moreover, NK cell numbers, percentages, maturation and functions were preserved in the presence of Artemisinin in vitro, suggesting that Artemisinin displays detrimental effects only on tumor cells but not on immune cells. These data reveal a novel anti-tumor mechanism of Artemisinin and demonstrate that Artemisinin could be a promising drug candidate for cancer treatment.