The Effects of Artemisinin on the Cytolytic Activity of Natural Killer (NK) Cells

Killing of xenogenous and virally infected homogenous target cells by shrimp lymphocyte-like haemocytes

Haemocytes play a crucial role in the invertebrate's immune system. In our lab, five subpopulations of shrimp haemocytes were identified in the past: hyalinocytes, granulocytes, semi-granulocytes and two subpopulations of non-phagocytic cells. In the latter two subpopulations, their characteristics such as having small cytoplasmic rims and not adhering to plastic cell-culture plates are very similar to those of mammalian lymphocytes. Therefore, they were designated lymphocyte-like haemocytes. Although little is known about their function, we hypothesize, based on their morphology, that they may have a cytotoxic activity like natural killer cells, with the ability to recognize and kill target cells. In our study, K562 cells and Sf9 cells were used as xenogenous target cells to detect the cytotoxic activity of the shrimp non-adherent lymphocyte-like haemocytes. Non-adherent haemocytes were collected and mixed with K562 cells and Sf9 cells at a 5:1 ratio and the binding activity was examined under a microscope. The binding rate of non-adherent haemocytes to K562 cells and Sf9 cells reached 6.6 % and 2.4 % after 240 min of culture, respectively. Then, the killing activity of non-adherent haemocytes was detected by an EMA staining (fluorescence microscopy), which showed 3.75 % dead K562 cells and 1.025 % dead Sf9 cells, and by Sytox® blue staining (flow cytometry), which showed 4.97 % of dead K562 cells. Next, a killing assay was developed to visualize the killing activity of shrimp non-adherent haemocytes. Non-adherent haemocytes were pre-labeled in blue (CellTracker blue) and K562/Sf9 cells in green (CFSE); dead cells were differentially stained red with ethidium bromide. The cytotoxic activity increased and reached a level of 2.59 % in K562 cells and 0.925 % in Sf9 cells at 120 min after co-culture. Furthermore, in the co-cultures of non-adherent haemocytes with K562 cells and Sf9 cells, upregulation of the gene and protein expression of the cytotoxic molecules torso-like protein and granzyme B was observed by RT-qPCR at 240 min and western blotting at 180 min. Additionally, non-adherent haemocytes were co-cultured with WSSV-inoculated shrimp ovary and lymphoid organ cells to detect the cytotoxicity to homogenous target cells. The binding activity started at 60 min in both the ovary and lymphoid organ cultures and reached at 240 min 50.62 % and 40.7 %, respectively. The killing activity was detected by EMA staining and the percentage of dead ovary and lymphoid organ cells increased respectively from 10.84 % to 6.89 % at 0 min to 13.09 % and 8.37 % at 240 min. In conclusion, we demonstrated the existence of cytotoxic activity of shrimp lymphocyte-like haemocytes against xenogenous cells from mammals and insects and against WSSV-infected homogenous shrimp cells.

Paulownin elicits anti-tumor effects by enhancing NK cell cytotoxicity through JNK pathway activation

Paulownin, a natural compound derived from Paulownia tomentosa wood, exhibits various physiological functions, including anti-bacterial and anti-fungal effects. However, the impact of paulownin on natural killer (NK) cell immune activity remains largely unknown. In this study, we investigated the effect of paulownin on NK cell activity both in vitro and in vivo, and explored its potential mechanisms. NK-92 cells were used for in vitro experiments and a BALB/c mouse model with B16F10 cells injected subcutaneously were used for in vivo anti-tumor analysis. We found that paulownin enhanced the cytolytic activity of NK-92 cells against leukemia, human colon, and human lung cancer cell lines. Paulownin treatment increased the expression of the degranulation marker protein CD107a and cytolytic granules, including granzyme B and perforin in NK-92 cells. Moreover, these enhancements of cytotoxicity and the expression of cytolytic granules induced by paulownin were also observed in human primary NK cells. Signaling studies showed that paulownin promoted the phosphorylation of JNK. The increased perforin expression and elevated cytotoxic activity induced by paulownin were effectively inhibited by pre-treatment with a JNK inhibitor. In vivo studies demonstrated that the administration of paulownin suppressed the growth of B16F10 melanoma cells allografted into mice. Paulownin administration promoted the activation of NK cells in the spleen of mice, resulting in enhanced cytotoxicity against YAC-1 cells. Moreover, the anti-tumor effects of paulownin were reduced upon the depletion of NK cells. Therefore, these results suggest that paulownin enhances NK cell cytotoxicity by activating the JNK signaling pathway and provide significant implications for developing new strategies for cancer immunotherapy.

Lacticaseibacillus casei K11 exerts immunomodulatory effects by enhancing natural killer cell cytotoxicity via the extracellular regulated-protein kinase pathway

PURPOSE

Probiotics can serve as immunomodulators that regulate the activation of immune cells. This study aimed to screen potential probiotic strains that can enhance NK cell toxicity to improve host immunity.

METHODS

In this investigation, we examined three potential probiotic strains, namely Lactiplantibacillus plantarum YZX21 (YZX21), Bifidobacterium bifidum FL-276.1 (FL-276.1) and Lacticaseibacillus casei K11 (K11), to assess their capacity in modulating NK cytotoxicity both in vitro and in vivo, while elucidating the underlying mechanisms involved.

RESULTS

The findings demonstrated that K11 exhibited superior efficacy in enhancing NK cytotoxicity. Subsequent analysis revealed that K11 significantly augmented the secretion of perforin and granzyme B by NK cells through activation of receptors NKp30 and NKp46 via the extracellular signal-regulated kinase (ERK) pathway. Furthermore, heat-inactivated K11 also enhanced NK cell activity to an extent comparable to live bacteria, with lipoteichoic acid from K11 identified as a crucial factor mediating the activation of NK cell cytotoxicity.

CONCLUSION

Our study suggests that K11 may have potential applications as probiotics or postbiotics for regulating NK cell cytotoxicity to enhance immunity.

Case Report: Cord blood-derived natural killer cells as new potential immunotherapy drug for solid tumor: a case study for endometrial cancer

Adoptive transfer of natural killer (NK) cells represents a viable treatment method for patients with advanced malignancies. Our team previously developed a simple, safe, and cost-effective method for obtaining high yields of pure and functional NK cells from cord blood (CB) without the need for cell sorting, feeder cells, or multiple cytokines. We present the case of a 52-year-old female patient diagnosed with poorly differentiated stage IVB (T3N2M1) endometrial cancer, who exhibited leukemoid reaction and pretreatment thrombocytosis as paraneoplastic syndromes. The patient received two courses of CB-derived NK (CB-NK) cell immunotherapy between March and September 2022, due to her extremely low NK cell activity. Two available CB units matched at 8/10 HLA with KIR-mismatch were chosen, and we were able to produce NK cells with high yield (>1.0×10¹⁰ NK cells), purity (>90%), and function (>80%) from CB without cell sorting, feeder cells, or multiple cytokines. These cells were then adoptively transferred to the patient. No adverse effects or graft-versus-host disease were observed after infusion of CB-NK cells. Our clinical experience supports the efficacy of CB-NK cell treatment in increasing NK cell activity, depleting tumor activity, improving quality of life, and reducing the size of abdominal and pelvic masses with the disappearance of multiple lymph node metastases through the regulation of systemic antitumor immunity. Remarkably, the white blood cell and platelet counts decreased to normal levels after CB-NK cell immunotherapy. This clinical work suggests that CB-NK cell immunotherapy holds promise as a therapeutic approach for endometrial cancer.

Natural biomolecules and derivatives as anticancer immunomodulatory agents

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

Natural Products and their Derivatives as Immune Check Point Inhibitors: Targeting Cytokine/Chemokine Signalling in Cancer

Cancer immunotherapy is the new generation and widely accepted form of tumour treatment. It is, however, associated with exclusive challenges which include organ-specific inflammation, and single-target strategies. Therefore, approaches that can enhance the efficiency of existing immunotherapies and expand their indications are required for the further development of immunotherapy. Natural products and medicines are stated to have this desired effect on cancer immunotherapy (adoptive immune-cells therapy, cancer vaccines, and immune-check point inhibitors). They refurbish the immunosuppressed tumour microenvironment, which is the primary location of interaction of tumour cells with the host immune system. Various immune cell subsets, via interaction with cytokine/chemokine receptors, are recruited into this microenvironment, and these subsets have roles in tumour progression and treatment responsiveness. This review summarises cytokine/chemokine signalling, types of cancer immunotherapy and the herbal medicine-derived natural products targeting cytokine/chemokines and immune checkpoints. These natural compounds possess immunomodulatory activities and exert their anti-tumour effect by either blocking the interaction or modulating the expression of the proteins linked with immune checkpoint signaling pathways. Some compounds also show a synergistic effect in combination with existing monoclonal antibody drugs to reverse the tumour microenvironment. Additionally, we have also reported some studies about the derivatives and formulations used to overcome the limitations of natural forms. This review can provide important insights for directing future research.

Targeting Inhibition of Accumulation and Function of Myeloid-Derived Suppressor Cells by Artemisinin via PI3K/AKT, mTOR, and MAPK Pathways Enhances Anti-PD-L1 Immunotherapy in Melanoma and Liver Tumors

Despite the remarkable success and efficacy of immune checkpoint blockade (ICB) therapy such as anti-PD-L1 antibody in treating cancers, myeloid-derived suppressor cells (MDSCs) that lead to the formation of the protumor immunosuppressive microenvironment are one of the major contributors to ICB resistance. Therefore, inhibition of MDSC accumulation and function is critical for further enhancing the therapeutic efficacy of anti-PD-L1 antibody in a majority of cancer patients. Artemisinin (ART), the most effective antimalarial drug with tumoricidal and immunoregulatory activities, is a potential option for cancer treatment. Although ART is reported to reduce MDSC levels in 4T1 breast tumor model and improve the therapeutic efficacy of anti-PD-L1 antibody in T cell lymphoma-bearing mice, how ART influences MDSC accumulation, function, and molecular pathways as well as MDSC-mediated anti-PD-L1 resistance in melanoma or liver tumors remains unknown. Here, we reported that ART blocks the accumulation and function of MDSCs by polarizing M2-like tumor-promoting phenotype towards M1-like antitumor one. This switch is regulated via PI3K/AKT, mTOR, and MAPK signaling pathways. Targeting MDSCs by ART could significantly reduce tumor growth in various mouse models. More importantly, the ART therapy remarkably enhanced the efficacy of anti-PD-L1 immunotherapy in tumor-bearing mice through promoting antitumor T cell infiltration and proliferation. These findings indicate that ART controls the functional polarization of MDSCs and targeting MDSCs by ART provides a novel therapeutic strategy to enhance anti-PD-L1 cancer immunotherapy.

Regulation of in vivo delivery of nanomedicines by herbal medicines

Nanomedicines are of increasing scrutiny due to their improved efficacy and/or mitigated side effects. They can be integrated with many other therapeutics to further boost the clinical benefits. Among those, herbal medicines are arousing great interest to be combined with nanomedicines to exert synergistic effects in multifaceted mechanisms. The in vivo performance of nanomedicines which determines the therapeutic efficacy and safety is believed to be heavily influenced by the physio-pathological characters of the body. Activation of multiple immune factors, e.g., complement system, phagocytic cells, lymphocytes, and among many others, can affect the fate of nanomedicines in blood circulation, biodistribution, interaction with single cells and intracellular transport. Immunomodulatory effects and metabolic regulation by herbal medicines have been widely witnessed during the past decades, which alter the physio-pathological conditions and dramatically affect in vivo delivery of nanomedicines. In this review, we summarize recent progress of understanding on the in vivo delivery process of nanomedicines and analyze the major affecting factors that regulate the interaction of nanomedicines with organisms. We discuss the immunomodulatory roles and metabolic regulation by herbal medicines and their effects on in vivo delivery process of nanomedicines, as well as the prospective clinical benefits from the combination of nanomedicines and herbal medicines.

Progress in Redirecting Antiparasitic Drugs for Cancer Treatment

Drug repurposing is a feasible strategy in developing novel medications. Regarding the cancer field, scientists are continuously making efforts to redirect conventional drugs into cancer treatment. This approach aims at exploring new applications in the existing agents. Antiparasitic medications, including artemisinin derivatives (ARTs), quinine-related compounds, niclosamide, ivermectin, albendazole derivatives, nitazoxanide and pyrimethamine, have been deeply investigated and widely applied in treating various parasitic diseases for a long time. Generally, their pharmacokinetic and pharmacodynamic properties are well understood, while the side effects are roughly acceptable. Scientists noticed that some of these agents have anticancer potentials and explored the underlying mechanisms to achieve drug repurposing. Recent studies show that these agents inhibit cancer progression via multiple interesting ways, inducing ferroptosis induction, autophagy regulation, mitochondrial disturbance, immunoregulation, and metabolic disruption. In this review, we summarize the recent advancement in uncovering antiparasitic drugs' anticancer properties from the perspective of their pharmacological targets. Instead of paying attention to the previously discovered mechanisms, we focus more on newly emerging ones that are worth noticing. While most investigations are focusing on the mechanisms of their antiparasitic effect, more in vivo exploration in clinical trials in the future is necessary. Moreover, we also paid attention to what limits the clinical application of these agents. For some of these agents like ARTs and niclosamide, drug modification, novel delivery system invention, or drug combination are strongly recommended for future exploration.

Repositioning of Antiparasitic Drugs for Tumor Treatment

Drug repositioning is a strategy for identifying new antitumor drugs; this strategy allows existing and approved clinical drugs to be innovatively repurposed to treat tumors. Based on the similarities between parasitic diseases and cancer, recent studies aimed to investigate the efficacy of existing antiparasitic drugs in cancer. In this review, we selected two antihelminthic drugs (macrolides and benzimidazoles) and two antiprotozoal drugs (artemisinin and its derivatives, and quinolines) and summarized the research progresses made to date on the role of these drugs in cancer. Overall, these drugs regulate tumor growth via multiple targets, pathways, and modes of action. These antiparasitic drugs are good candidates for comprehensive, in-depth analyses of tumor occurrence and development. In-depth studies may improve the current tumor diagnoses and treatment regimens. However, for clinical application, current investigations are still insufficient, warranting more comprehensive analyses.

Artesunate Switches Monocytes to an Inflammatory Phenotype with the Ability to Kill Leukemic Cells

Monocytes are components of the tumor microenvironment related to cancer progression and immune escape. Therapeutic strategies for reprogramming monocytes from a tumor-supporting phenotype towards a tumoricidal phenotype are of great interest. Artesunate (ART) may be an interesting option for cancer treatment; however, the role of ART in regulating the inflammatory tumor microenvironment has not yet been investigated. Our aim is to evaluate the immunomodulatory potential of ART in vitro in human primary monocytes. ART treatment induced an increase in inflammatory monocytes (CD14^highCD16⁻) with HLA-DR high expression and MCP-1/IL-1β release. On the other hand, ART treatment reduced CD206 and CD163 expression, and abolished the monocyte population known as non-classical and intermediate. Leukemia cells in contact with monocytes programmed with ART presented enhanced in vitro apoptosis suggesting that monocytes acquired the ability to kill leukemic cells. ART induced changes in the monocyte phenotype were mediated by JAK2/STAT3 downregulation. The induction of immunosuppressive environment is an important step for cancer progression. ART showed an immunomodulatory activity, leading immune cells to an antitumor phenotype and could be a candidate for immunotherapy in cancer patients.

Development of Potential Antitumor Agents from the Scaffolds of Plant-Derived Terpenoid Lactones

Naturally occurring terpenoid lactones and their synthetic derivatives have attracted increasing interest for their promising antitumor activity and potential utilization in the discovery and design of new antitumor agents. In the present perspective article, selected plant-derived five-membered γ-lactones and six-membered δ-lactones that occur with terpenoid scaffolds are reviewed, with their structures, cancer cell line cytotoxicity and in vivo antitumor activity, structure-activity relationships, mechanism of action, and the potential for developing cancer chemotherapeutic agents discussed in each case. The compounds presented include artemisinin (ART, 1), parthenolide (PTL, 2), thapsigargin (TPG, 3), andrographolide (AGL, 4), ginkgolide B (GKL B, 5), jolkinolide B (JKL B, 6), nagilactone E (NGL E, 7), triptolide (TPL, 8), bruceantin (BRC, 9), dichapetalin A (DCT A, 10), and limonin (LMN, 11), and their naturally occurring analogues and synthetic derivatives. It is hoped that this contribution will be supportive of the future development of additional efficacious anticancer agents derived from natural products.

Pyronaridine: An update of its pharmacological activities and mechanisms of action

Pyronaridine (PYR) is an erythrocytic schizonticide with a potent antimalarial activity against multidrug-resistant Plasmodium. The drug is used in combination with artesunate for the treatment of uncomplicated P. falciparum malaria, in adults and children. The present review briefly retraces the discovery of PYR and recent antimalarial studies which has led to the approval of PYR/artesunate combination (Pyramax) by the European Medicines Agency to treat uncomplicated malaria worldwide. PYR also presents a marked antitumor activity and has revealed efficacy for the treatment of other parasitic diseases (notably Babesia and Trypanosoma infections) and to mitigate the Ebola virus propagation. On the one hand, PYR functions has an inhibitor of hemozoin (biomineral malaria pigment, by-product of hemoglobin digestion) formation, blocking the biopolymerization of β-hematin and thus facilitating the accumulation of toxic hematin into the digestive vacuole of the parasite. On the other hand, PYR is a bona fide DNA-intercalating agent and an inhibitor of DNA topoisomerase 2, leading to DNA damages and cell death. Inhibition of hematin polymerization represents the prime mechanism at the origin of the antimalarial activity, whereas anticancer effects relies essentially on the interference with DNA metabolism, as with structurally related anticancer drugs like amsacrine and quinacrine. In addition, recent studies point to an immune modulatory activity of PYR and the implication of a mitochondrial oxidative pathway. An analogy with the mechanism of action of artemisinin drugs is underlined. In brief, the biological actions of pyronaridine are recapitulated to shed light on the diverse health benefits of this unsung drug.

Natural products and their derivatives: Promising modulators of tumor immunotherapy

A wealth of evidence supports the role of tumor immunotherapy as a vital therapeutic option in cancer. In recent decades, accumulated studies have revealed the anticancer activities of natural products and their derivatives. Increasing interest has been driven toward finding novel potential modulators of tumor immunotherapy from natural products, a hot research topic worldwide. These works of research mainly focused on natural products, including polyphenols (e.g., curcumin, resveratrol), cardiotonic steroids (e.g., bufalin and digoxin), terpenoids (e.g., paclitaxel and artemisinins), and polysaccharide extracts (e.g., lentinan). Compelling data highlight that natural products have a promising future in tumor immunotherapy. Considering the importance and significance of this topic, we initially discussed the integrated research progress of natural products and their derivatives, including target T cells, macrophages, B cells, NKs, regulatory T cells, myeloid‐derived suppressor cells, inflammatory cytokines and chemokines, immunogenic cell death, and immune checkpoints. Furthermore, these natural compounds inactivate several key pathways, including NF‐κB, PI3K/Akt, MAPK, and JAK/STAT pathways. Here, we performed a deep generalization, analysis, and summarization of the previous achievements, recent progress, and the bottlenecks in the development of natural products as tumor immunotherapy. We expect this review to provide some insight for guiding future research.

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.

Suppression of Hepatocellular Carcinoma Progression through FOXM1 and EMT Inhibition via Hydroxygenkwanin-Induced miR-320a Expression

Daphne genkwa, a Chinese medicinal herb, is used frequently in Southeast Asian countries to treat diseases; the flavonoid hydroxygenkwanin (HGK) is extracted from its flower buds. The bioactivity of HGK, particularly as an anti-liver cancer agent, has not been explored. In this study, human hepatocellular carcinoma (HCC) cell lines and an animal xenograft model were employed to investigate both the activity of HGK against liver cancer and its cellular signaling mechanisms. HCC cells treated with HGK were subjected to cell function assays. Whole transcriptome sequencing was used to identify genes whose expression was influenced by HGK, and the flavonoid’s cancer suppression mechanisms were further investigated through gain- and loss-of-function assays. Finally, in vitro findings were tested in a mouse xenograft model. The data showed that HGK induced the expression of the microRNA miR-320a, which in turn inhibited the expression of the transcription factor ‘forkhead box protein M1’ (FOXM1) and downstream FOXM1-regulated proteins related to epithelial–mesenchymal transition, thereby leading to the suppression of liver cancer cell growth and invasion. Significant inhibition of tumor growth was also observed in HGK-treated mice. Hence, the present study demonstrated the activity of HGK against liver cancer and validated its potential use as a therapeutic agent.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

Psorachromene Suppresses Oral Squamous Cell Carcinoma Progression by Inhibiting Long Non-coding RNA GAS5 Mediated Epithelial-Mesenchymal Transition

The extract of the seeds of Psoralea corylifolia Linn. (P. corylifolia) have been shown to display anti-tumor activity. However, the prospects of the active compounds from this plant in the treatment of oral squamous cell carcinoma (OSCC) remains unclear. In the present study, the antitumor effects of psorachromene, a flavonoid extracted from the seeds of P. corylifolia, were investigated using cells and animal models of OSCC; the downstream regulatory mechanisms were also elucidated. The results showed that psorachromene significantly repressed cell proliferation, migration, and invasiveness and increased the toxic effects of chemotherapeutic agents against OSCC cells. The repressive effects of psorachromene were attributable to the inhibition of EGFR-Slug signaling, and the induction of G2/M arrest and apoptosis in the OSCC cells. Additionally, we found that psorachromene induced the expression of tumor suppressor long non-coding ribonucleic acid (RNA) growth arrest-specific transcript 5 (GAS5) and the activation of its downstream anticancer mechanisms. Animal experiments also showed noticeable inhibition of tumor growth, without significant physiological toxicity. The findings indicate that psorachromene displays anti-tumor activity in OSCC, and warrants further investigation as a potential agent for clinical application.

Artesunate enhances the immune response of rabies vaccine as an adjuvant

Rabies is an ancient zoonosis that continues to be an important health problem worldwide. Vaccination with rabies vaccine is the most important strategy to prevent rabies. Adjuvants contribute to the immune response of viral vaccine. The aim of this study was to investigate whether artemisinin derivatives artesunate and dihydroartemisinin could enhance the immunogenicity of inactivated rabies virus in mice. Administration of artesunate or dihydroartemisinin by intramuscular injection at a dose of 5 mg/kg did not cause body weight loss and unusual symptoms in mice. Mice were immunized with inactivated CVS-11 or inactivated rHEP-dG together with either artesunate or dihydroartemisinin through intramuscular injection. Blood samples were collected to investigate the virus-neutralizing antibody (VNA) titers, and challenge assays were then conducted. The results showed that the rabies VNA titers in mice co-treated with artesunate rather than dihydroartemisinin were significantly higher than in the control animals treated with the phosphate buffered saline (PBS). In addition, mice co-treated with artesunate survived from lethal rabies virus challenge compared with those treated with PBS. In contrast, co-treatment with dihydroartemisinin did not improve the survival rate of the challenged mice. The findings indicate that artesunate could be used as a new candidate adjuvant for rabies vaccination.

Dihydroartemisinin Ameliorated Ovalbumin-Induced Asthma in Mice via Regulation of MiR-183C

BACKGROUND The purpose of the present study was to investigate the function and mechanism of dihydroartemisinin (DHA) in treating ovalbumin-induced asthma in BALB/c mice. MATERIAL AND METHODS Thirty female BALB/c mice were randomly separated into 3 groups: the control group, the asthma model group stimulated by ovalbumin (OVA group), and the DHA treatment group (DHA group). The therapeutic effects and potential pharmacological mechanisms of DHA were specifically clarified by examining its effects on asthma-related phenomena, such as body weight, lung function, cell counts in bronchoalveolar lavage fluid (BALF), and hemotoxin and eosin staining. In addition, the expression of inflammatory factors was checked by enzyme-linked immunosorbent assay kits, and fractions of Th17 cells were detected by FACS analysis. Moreover, the downstream molecular pathway of IL-6/Stat3 (interleukin-6/signal transducer and activator of transcription 3) and expression of miR-183C was investigated by western blot and/or quantitative real-time polymerase chain reaction. Luciferase assay was used to reveal the function of miR-183C on the transcriptional regulation of Foxo1 (forkhead box O). RESULTS DHA administration significantly relieved the severity of the asthma through its effect on body weight, survival rate, and airway pressure. DHA was able to ameliorate lung damage in terms of pathological morphology and it reduced the percentage of helper T 17 (Th17) cells and the secretion of cytokines. As a result, the activity of the IL-6/Stat3 pathway was inhibited by DHA. In addition, the adoption of DHA decreased the expression of miR-183C but increased the expression of the transcription factor Foxo1. CONCLUSIONS Our results suggest that the therapeutic effects of DHA on asthma are partially realized via the regulation of miR-183C and IL-6/Stat3 pathway.

Supplementation with Bifidobacterium longum Bar33 and Lactobacillus helveticus Bar13 mixture improves immunity in elderly humans (over 75 years) and aged mice

OBJECTIVE

Aging induces several physiologic and immune changes. The usefulness of probiotics in ameliorating age-related disorders remains largely unexplored. The aim of this study was to evaluate the effectiveness of a Bifidobacterium longum Bar33 and Lactobacillus helveticus Bar13 mixture in improving the physiologic status and immunity of older adults (over 75 years). Furthermore, the possible role of such mixture in ameliorating gut immunity in aged mice was investigated.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted with 98 adults (84.6 ± 7.8 y), supplemented for 30 d with a biscuit containing a probiotic mixture of B. longum Bar33 and L. helveticus Bar13 (1:1), or no probiotics, as placebo. Blood was collected for analysis of biochemical parameters, lymphocyte subpopulations, natural killer activity, and cytokine release. Aged Balb/c mice received the same probiotic mixture or placebo daily for 28 d, then blood and intestinal lymphocyte subpopulations were analyzed.

RESULTS

The probiotic mixture ameliorated immune response in older adults by increasing naive, activated memory, regulatory T cells, B cells, and natural killer activity and decreasing memory T cells compared with placebo (P < 0.05). The biochemical parameters did not change after probiotic supplementation. In the gut of old mice, the two probiotics modulated cells crucial for gut immune homeostasis by increasing regulatory T (Treg and Tr1) and decreasing γδ T cells compared with control mice (P < 0.05). In addition, B cells increased in the gut and blood of probiotic-treated mice.

CONCLUSION

Results from the present study data indicated that B. longum Bar33 and L. helveticus Bar13 improve immune function at intestinal and peripheral sites in aging.

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.

α-Tocopheryl succinate-suppressed development of cerebral malaria in mice

α-Tocopheryl succinate (α-TOS), a derivative of vitamin E, is synthesized by esterification of α-tocopherol. It has been reported that α-TOS inhibits the mitochondrial complex II resulting in generation of reactive oxygen species, which triggers selective apoptosis in a large number of cancer cells, while it appears largely non-toxic towards normal cells. Plasmodium parasites are well known to have high sensitivity to oxidative stress. Thus, α-TOS is suspected to impact Plasmodium parasites by oxidative stress. In this study, to ascertain whether α-TOS is an appropriate candidate for an anti-malarial drug, C57BL/6J mice were infected with P. yoelii 17XL and P. berghei ANKA, a lethal strain of rodent malaria and experimental cerebral malaria (ECM), and treated with several concentrations of α-TOS by intraperitoneal administration on 1, 3, 5, and 7 days post infection (dpi). In addition, the permeability of the blood brain barrier (BBB) was examined by Evans blue staining in ECM on 7 dpi. As a result of α-TOS treatment, parasitemia was decreased and survival rate was significantly increased in mice infected with both parasites. Furthermore, the intensity of Evans blue staining on brains taken from α-TOS-treated mice was weaker than that of untreated mice. This means that α-TOS might inhibit the breakdown of BBB and progress of cerebral malaria. These findings indicate that vitamin E derivatives like α-TOS might be a potential candidate for treatment drugs against malaria.

Corylin increases the sensitivity of hepatocellular carcinoma cells to chemotherapy through long noncoding RNA RAD51-AS1-mediated inhibition of DNA repair

Corylin, a biologically active agent extracted from Psoralea corylifolia L. (Fabaceae), promotes bone differentiation and inhibits inflammation. Currently, few reports have addressed the biological functions that are regulated by corylin, and to date, no studies have investigated its antitumor activity. In this study, we used cell functional assays to analyze the antitumor activity of corylin in hepatocellular carcinoma (HCC). Furthermore, whole-transcriptome assays were performed to identify the downstream genes that were regulated by corylin, and gain-of-function and loss-of-function experiments were conducted to examine the regulatory roles of the above genes. We found that corylin significantly inhibited the proliferation, migration, and invasion of HCC cells and increased the toxic effects of chemotherapeutic agents against HCC cells. These properties were due to the induction of a long noncoding RNA, RAD51-AS1, which bound to RAD51 mRNA, thereby inhibiting RAD51 protein expression, thus inhibiting the DNA damage repair ability of HCC cells. Animal experiments also showed that a combination treatment with corylin significantly increased the inhibitory effects of the chemotherapeutic agent etoposide (VP16) on tumor growth. These findings indicate that corylin has strong potential as an adjuvant drug in HCC treatment and that corylin can strengthen the therapeutic efficacy of chemotherapy and radiotherapy.

Corylin Suppresses Hepatocellular Carcinoma Progression via the Inhibition of Epithelial-Mesenchymal Transition, Mediated by Long Noncoding RNA GAS5

Corylin is a flavonoid extracted from the nuts of Psoralea corylifolia L. (Fabaceae), which is a widely used anti-inflammatory and anticancer herb in China. Recent studies revealed antioxidant, anti-inflammatory, and bone differentiation–promoting effects of corylin. However, there are no studies examining the anticancer activity of corylin. In this study, we used cells and animal models to examine the antitumor effects of corylin on hepatocellular carcinoma (HCC) and then studied its downstream regulatory mechanisms. The results showed that corylin significantly inhibited the proliferation, migration, and invasiveness of HCC cells and suppressed epithelial–mesenchymal transition. We found that the anti-HCC mechanism of corylin’s action lies in the upregulation of tumor suppressor long noncoding RNA growth arrest-specific transcript 5 (GAS5) and the activation of its downstream anticancer pathways. In animal experiments, we also found that corylin can significantly inhibit tumor growth without significant physiological toxicity. The above results suggest that corylin has anti-HCC effects and good potential as a clinical treatment.