Concentration-dependent biphasic effects of resveratrol on human natural killer cells in vitro

Enhancing NK Cell Antitumor Activity With Natural Compounds: Research Advances and Molecular Mechanisms

In recent years, immunotherapy has become a novel antitumor strategy in addition to traditional surgery, radiotherapy, and chemotherapy and has exhibited promising results in clinical applications. Despite significant breakthroughs in immunotherapy, such as immune checkpoint blockade and CAR-T cell therapy, it remains necessary to develop more efficacious, safer, and cheaper immunotherapeutic drugs due to factors including small reaction populations, acquired resistance, adverse side effects, and high costs. Natural killer (NK) cells are preeminent cytotoxic lymphocytes of the innate immune system that act as the first line of defense against tumors and synergistically enhance the adaptive immune response of T lymphocytes. Therefore, boosting the antitumor function of NK cells is an important direction in the development of immunotherapy. For decades, various immunotherapies such as adoptive cell therapy, antibody drugs, cytokines supplement, and chemical immunomodulators have been developing rapidly to improve the function of NK cells. Compared to biological immunotherapy, immunomodulators derived from natural products have outstanding advantages of low immunogenicity, multi-targeting, and cost-effectiveness. Currently, increasing attention is being focused on discovering NK cell-stimulating agents from natural products, such as polysaccharides, alkaloids, terpenoids, saponins, phenolics, and quinones. This review aims to categorize and summarize the comprehensive research progress on these natural products, discuss their potential molecular mechanisms in regulating NK cells, and explore their clinical applications as standalone treatments or in combination with conventional chemotherapy regimens.

Resveratrol from Peanut Sprout Extract Promotes NK Cell Activation and Antitumor Activity

Natural killer (NK) cells are innate immune cells that are crucial for anticancer activity and have been developed as an immune cell therapy for leukemia. However, their limited effectiveness against solid tumors has prompted research into methods to enhance NK cell activity through combination therapies. Health supplements capable of boosting immune surveillance against tumor cells are gaining attention owing to their potential benefits. Resveratrol, a stilbenoid produced by several plants including peanuts and grapes, reportedly exerts anticancer effects and can activate immune cells. The peanut sprout extract cultivated with fermented sawdust medium (PSEFS) is rich in resveratrol, leveraging its health benefits in terms of the dry weight of herbal products, thus maximizing the utilization of resveratrol's beneficial properties. Our study compared the efficacy of resveratrol and PSEFS and revealed that PSEFS significantly enhanced NK cell activation compared with an equivalent dose of resveratrol. We investigated the ability of PSEFS to potentiate NK cell anticancer activity, focusing on NK cell survival, tumor cell lysis, and NK cell activation in PSEFS-administered mice. Our findings suggest that PSEFS could be a potential NK cell booster for cancer immunotherapy.

Enhanced Endothelialization Using Resveratrol-Loaded Polylactic Acid-Coated Left Atrial Appendage Occluders in a Canine Model

Left atrial appendage occlusion (LAAO) is a well-established alternative to anticoagulation therapy for patients with atrial fibrillation who have a high bleeding risk. After occluder implantation, anticoagulation therapy is still required for at least 45 days until complete LAAO is achieved by neoendocardial coverage of the device. We applied a polylactic acid-resveratrol coating to the LAAO membrane to enhance endothelialization with the goal of shortening the anticoagulation therapy duration. Eighteen dogs were randomly divided into the experimental group (coated occluders) or the control group (noncoated occluders). The dogs were sacrificed in cohorts at days 14, 28, and 90 for anatomical and pathological examination to evaluate endothelialization and thrombus formation. Transesophageal echocardiography (TEE) was performed before sacrifice to evaluate device-related adverse events. According to the anatomical and pathological examinations, all except one LAAO cover exhibited larger or thicker tissue or neoendocardial coverage in the experimental group compared with the control group at the same sacrifice time points. All connection hubs were densely covered by endothelial cells at 90 days and completely covered at 28 days in the experimental group, while all connection hubs were thinly covered at 90 days and two connection hubs were exposed at 28 days in the control group. Pathological examination revealed no thrombus formation in the experimental group, while a small amount of thrombus was observed in one dog at 90 days and in two dogs at 28 days in the control group. Finally, TEE showed no peri-device leakage (PDL) in the experimental group, whereas a small amount of PDL was detected in one dog (3.2 mm) at 28 days and in one dog (3.7 mm) at 14 days in the control group. The resveratrol-loaded polylactic acid-covered LAAO device enhanced endothelialization and reduced thrombus formation and PDL. This effect could possibly reduce the anticoagulation therapy duration.

Potential of resveratrol in the treatment of systemic lupus erythematosus (Review)

Systemic lupus erythematosus (SLE) is a multi‑system chronic autoimmune disease with a complex occurrence and development process, associated with immune disorders, uncertain prognosis, and treatment modalities which vary by patient and disease activity. At present, the clinical treatment of SLE mainly focuses on hormones and immunosuppressants. In recent years, the research on new treatment strategies for SLE has been booming, and strong preclinical results and clinical research have promoted the development of numerous drugs (such as rituximab and orencia), but numerous of these drugs have failed to achieve effectiveness in clinical trials, and there are some adverse reactions. Recent evidence suggests that resveratrol (RSV) has the effect of ameliorating immune disorders by inhibiting overactivation of immune cells. In the present review, advances in research on the protective effects and potential mechanisms of RSV against SLE are summarized and the potential potency of RSV and its use as a promising therapeutic option for the treatment of SLE are highlighted.

Transcriptome analysis reveals high concentration of resveratrol promotes lipid synthesis and induces apoptosis in Siberian sturgeon (Acipenser baerii)

Resveratrol has been reported to promote immunity and decrease oxidative stress, but which demonstrates biphasic effects relied on the use concentration. In this study, the effects of diet supplement with a relative high concentration of resveratrol (0.32 mg/kg) on metabolism, antioxidation and apoptosis of liver were investigated in Siberian sturgeon. The results showed that resveratrol significantly increased the lipid synthesis and the apoptosis, but did not either activate the antioxidant NRF2/KEAP1 pathway or enhance the antioxidant enzyme activity. Transcriptome analysis revealed significant changes in regulatory pathways related to glycolipid, including PPAR signaling pathway, Insulin signaling pathway, Fatty acid biosynthesis, and Glycolysis/Gluconeogenesis. In addition, resveratrol significantly increased the lipid synthesis genes (accα and fas), fatty acid transport gene (fatp 6) and gluconeogenesis gene (gck), but decreased the survival-promoting genes (gadd45β and igf 1). These findings highlight a significant effect of resveratrol on glycolipid metabolism in Siberian sturgeon. Moreover, this study also demonstrated that 0.32 mg/kg resveratrol has physiological toxicity to the liver of Siberian sturgeon, indicating that this dose is too high for Siberian sturgeon. Thus, our study provides a valuable insight for future research and application of resveratrol in fish.

Enhancing the Anti-Tumor Efficacy of NK Cells on Canine Mammary Tumors through Resveratrol Activation

In order to explore the therapeutic effect of Resveratrol (Res)-activated Natural Killer (NK) cells on canine mammary tumors, this study employed a range of assays, including wound healing, colony formation, Transwell, flow cytometry, and Western blot experiments, to investigate the impact of Res-pretreated NK cells on canine mammary tumor cells in vitro. Additionally, a tumor-bearing mouse model was utilized to further analyze the therapeutic effects of Res-pretreated NK cells in vivo. The results showed that Res enhances the capacity of NK cells to induce apoptosis, pyroptosis, and ferroptosis in canine breast tumor cells, while also augmenting their influence on the migration, invasion, and epithelial-mesenchymal transition of these cells. Furthermore, pretreatment of NK cells with Res significantly amplified their inhibitory effect on breast tumor growth in vivo and promoted tumor tissue apoptosis. Additionally, Res enhanced the recruitment of NK cells to other immune cells in the body. In summary, Res has been shown to enhance the anti-breast-tumor effect of NK cells both in vitro and in vivo, offering a new avenue for optimizing immunotherapy for canine breast tumors.

The Combination of Bioavailable Concentrations of Curcumin and Resveratrol Shapes Immune Responses While Retaining the Ability to Reduce Cancer Cell Survival

The polyphenols Curcumin (CUR) and Resveratrol (RES) are widely described for their antitumoral effects. However, their low bioavailability is a drawback for their use in therapy. The aim of this study was to explore whether CUR and RES, used at a bioavailable concentration, could modulate immune responses while retaining antitumor activity and to determine whether CUR and RES effects on the immune responses of peripheral blood mononuclear cells (PBMCs) and tumor growth inhibition could be improved by their combination. We demonstrate that the low-dose combination of CUR and RES reduced the survival of cancer cell lines but had no effect on the viability of PBMCs. Although following CUR + RES treatment T lymphocytes showed an enhanced activated state, RES counteracted the increased IFN-γ expression induced by CUR in T cells and the polyphenol combination increased IL-10 production by T regulatory cells. On the other hand, the combined treatment enhanced NK cell activity through the up- and downregulation of activating and inhibitory receptors and increased CD68 expression levels on monocytes/macrophages. Overall, our results indicate that the combination of CUR and RES at low doses differentially shapes immune cells while retaining antitumor activity, support the use of this polyphenol combinations in anticancer therapy and suggest its possible application as adjuvant for NK cell-based immunotherapies.

Limocitrin increases cytotoxicity of KHYG-1 cells against K562 cells by modulating MAPK pathway

Natural killer (NK) cells are gaining popularity in the field of cancer immunotherapy. The present study was designed to investigate the effect of a natural flavonol compound limocitrin in increasing cytotoxicity of a permanent NK leukemia cell line KHYG-1 against an aggressive leukemia cell line K562. The findings revealed that limocitrin increased the expressions of cytolytic molecules perforin, granzymes A and B, and granulysin in KHYG-1 cells by inducing phosphorylation of transcription factor CREB, leading to increased lysis of K562 cells. Mechanistically, limocitrin was found to increase the expressions of t-Bid, cleaved caspase 3, and cleaved PARP to induce K562 cell apoptosis. Moreover, limocitrin reduced the expressions of SET and Ape1 to inhibit DNA repair mechanism, leading to caspase-independent K562 cell death. At the molecular level, limocitrin was found to increase the phosphorylation of ERK, p38, and JNK to increase granzyme B expression in KHYG-1 cells. Taken together, the study indicates that limocitrin increases cytotoxicity of NK cells against a range of cancer cells.

Shuterin Enhances the Cytotoxicity of the Natural Killer Leukemia Cell Line KHYG-1 by Increasing the Expression Levels of Granzyme B and IFN-γ through the MAPK and Ras/Raf Signaling Pathways

Natural killer (NK) cell therapy is an emerging tool for cancer immunotherapy. NK cells are isolated from peripheral blood, and their number and activity are limited. Therefore, primary NK cells should be expanded substantially, and their proliferation and cytotoxicity must be enhanced. Shuterin is a phytochemical isolated from Ficus thonningii. In this study, we explored the possible capacity of shuterin to enhance the proliferation and activity of KHYG-1 cells (an NK leukemia cell line). Shuterin enhanced the proliferation of KHYG-1 cells and their cytotoxicity to K562 cells. Moreover, this phytochemical induced the expression of granzyme B by promoting the phosphorylated cyclic adenosine monophosphate response element-binding protein (CREB) and mitogen-activated protein kinase (MAPK) signaling pathways. Furthermore, the secretion of interferon (IFN)-γ increased with increasing levels of shuterin in KHYG-1 cells and NK cells obtained from adults with head and neck squamous cell carcinoma. Shuterin appeared to induce IFN-γ secretion by increasing the expression of lectin-like transcript 1 and the phosphorylation of proteins involved in the Ras/Raf pathway. Thus, shuterin represents a promising agent for promoting the proliferation and cytotoxicity of NK cells.

Boosting immune system against cancer by resveratrol

Modulation of the immune system is a critical part of anticancer therapies including immunotherapy, chemotherapy, and radiotherapy. The aim of immunomodulation in cancer therapy is boosting immune system cells including CD8+ T lymphocytes and natural killer (NK) cells, as well as suppression of immunosuppressive responses by macrophages and regulatory T cells (Tregs). Usually, using single or dual modality can induce immune system responses against cancer. However, immunosuppressive responses attenuate antitumor immunity following cancer therapy. Using some agents to boost immune system's function against cancer can increase therapeutic efficiency of anticancer therapy. Resveratrol, as a natural agent, has shown ability to modulate the immune system to potentiate antitumor immunity. Resveratrol has been shown to induce the release of anticancer cytokines such as IFN-γ and TNF-α and also inhibits the release of TGF-β. It also can stimulate the polarization of CD4+ T cells and macrophages toward anticancer cells and reduce infiltration and polarization of immunosuppressive cells. Furthermore, resveratrol can sensitize cancer cells to the released dead signals by anticancer immune cells. This review explains how resveratrol can boost the immune system against cancer via modulation of immune cell responses within tumor.

Immunomodulation of Chinese Herbal Medicines on NK cell populations for cancer therapy: A systematic review

ETHNOPHARMACOLOGICAL RELEVANCE

Immunomodulation has become a crucial modality for cancer treatment. Chinese Herbal Medicines (CHMs) are expected as adjuvant therapy for immunomodulation against cancer, but face the key challenge of poor scientific evidence. Changes of natural killer (NK) cells on numbers and/or cytotoxicity are a novel respect to evaluate the immunomodulation of CHMs.

AIM OF THE STUDY

The purpose of this review is to investigate the immunomodulation of Chinese Herbal Medicines (CHMs) on NK cell populations for cancer therapy.

MATERIALS AND METHODS

A systematic review was conducted and outside mainstream electronic databases were screened for potential reference articles. This review tried to report and critically analyzed all the correlative studies, especially these clinical trials (3 CHM extracts and 11 CHM formulas).

RESULTS

Evidence-based functions of CHMs against cancer could be summarized as: (1) enhancement of NK cells activity or relative percentage; (2) prevention of tumor growth and metastasis; (3) relief on side-effects or complications of therapeutic strategies (i.e. chemotherapy, radiotherapy and resection). Briefly, most of cellular studies and two thirds animal studies were based on the extract or components of single herbs, whilst most of clinical trials were keen on formula or prescription of CHMs. The main components of CHMs were demonstrated active on promoting the cytotoxicity of NK cells, including Angelica sinensis, Ganoderma lucidum, Panax ginseng, Radix Astragali, Lentinus edodes, etc. CONCLUSIONS: This comprehensive review demonstrated NK cells activity was positively associated with quality of life but not survival benefit of cancer patients. Thus exploring the roles of NK cells in adjuvant therapy against cancer is confirmed to be beneficial to explore the underlying relationship between immunomodulation and quality of life.

Immunomodulatory effects of flavonoids: An experimental study on natural-killer-cell-mediated cytotoxicity against lung cancer and cytotoxic granule secretion profile

Background:

A new approach involving immune-cell-mediated cancer therapy has been adopted extensively for the sake of lung cancer treatments by utilizing natural killer (NK) cells. NK cell activity can be enhanced with certain agents, and among them are flavonoids. Thus, this study was conducted to investigate the immunomodulatory roles of apigenin, luteolin and quercetin on NK cell activity against lung cancer cells and on the secretions of perforin and granulysin profile.

Methods:

The NK-92 cells were grown in complete α-Minimum Essential Medium (MEM). NCI-H460 lung cancer cells were cultured in Roswell Park Memorial Institute 1640 media. NK cell activity against lung cancer cells were done using MTT(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The secretions of perforin and granulysin profiles were then analysed using enzyme-linked immunosorbent assay.

Results:

Apigenin, luteolin and quercetin significantly increased the NK-cell-mediated cytotoxic activity against lung cancer cells at concentrations 12.5 µg/ml and 25µg/ml ( P < 0.001). The secretion levels of perforin and granulysin from NK cells were also significantly enhanced with apigenin and luteolin treatment but not with quercetin.

Conclusions:

All three flavonoid compounds possessed some significant immunomodulatory actions on NK cell cytotoxic activity and granule secretion profiles towards lung cancer therapy.

Tea Bioactive Modulate Innate Immunity: In Perception to COVID-19 Pandemic

Innate immunity impairment led to disruption in cascade of signaling pathways upregulating pro-inflammatory cytokines, diminish interferons, depleted natural killer cells and activate reactive oxygen species production. These conditions severely affected body's ability to fight against infectious diseases and also plays a pivotal role in disease progression. Here, in emphasis is on nutritional immunity for regulating effective innate immune response for combating against infectious diseases like novel coronavirus disease (COVID 19). Drawing from discoveries on in-vitro experiments, animal models and human trials, tea polyphenols, micronutrients, and vitamins has the potential to modulate and enhance innate immune response. This article provides a comprehensive review on tea (Camellia sinensis L) infusion (a hot water extract of dried processed tea leaves prepared from young shoots of tea plant) as an innate immunity modulator. Tea infusion is rich in polyphenols; epigallocatechin gallate (EGCG) and theaflavin (TF), major green and black tea polyphenols, respectively. Studies showed their immunomodulatory competence. Tea infusions are also rich in alkaloids; caffeine and its intermediates, theophylline and theobromine, which have anti-inflammatory properties. Tea plant being an acidophilic perennial crop can accumulate different micronutrients, viz., copper (Cu), iron (Fe), manganese (Mn), selenium (Se), and zinc (Zn) from growing medium, i.e., from soil, which led to their considerable presence in tea infusion. Micronutrients are integral part of innate immune response. Overall, this review presents tea infusion as an important source of nutritional immunity which can enhance innate immune response in order to mitigate the unprecedented COVID-19 pandemic.

In vivo Anti-Cancer Effects of Resveratrol Mediated by NK Cell Activation

Natural killer (NK) cells are innate immune lymphocytes that play an important role in anti-viral and anti-tumour immune responses. Several cancer immunotherapy approaches targeting NK cells are currently in clinical or preclinical development. Here, we aimed to find food nutrients that activate NK cells and determine their usefulness as candidates for anti-cancer and anti-metastatic drugs. Resveratrol appeared to activate NK cells most effectively among the substances tested and synergistically increased IFN-γ secretion and NK cell cytotoxicity with interleukin-2 (IL-2). CD107a, NKp30, and NKG2D expression levels were upregulated on the surface of NK cells upon treatment with resveratrol in combination with IL-2 compared with treatment with IL-2 alone. Moreover, NK cell activity in human and mouse whole blood was enhanced upon treatment with resveratrol. Most importantly, administration of resveratrol effectively inhibited tumour growth and metastasis in mice. In conclusion, we suggest that resveratrol may represent a candidate anti-cancer drug that acts by activating NK cells in vivo.

Postulated Adjuvant Therapeutic Strategies for COVID-19

The number of COVID-19 patients is still growing exponentially worldwide due to the high transmissibility of the SARS-CoV-2 virus. Therapeutic agents currently under investigation are antiviral drugs, vaccines, and other adjuvants that could relieve symptoms or improve the healing process. In this review, twelve therapeutic agents that could play a role in prophylaxis or improvement of the COVID-19-associated symptoms (as add-on substances) are discussed. Agents were identified based on their known pharmacologic mechanism of action in viral and/or nonviral fields and are postulated to interact with one or more of the seven known mechanisms associated with the SARS-CoV-2 virus: (i) regulation of the immune system; (ii) virus entrance in the cell; (iii) virus replication; (iv) hyperinflammation; (v) oxidative stress; (vi) thrombosis; and (vii) endotheliitis. Selected agents were immune transfer factor (oligo- and polypeptides from porcine spleen, ultrafiltered at <10 kDa; Imuno TF®), anti-inflammatory natural blend (Uncaria tomentosa, Endopleura uchi and Haematoccocus pluvialis; Miodesin®), zinc, selenium, ascorbic acid, cholecalciferol, ferulic acid, spirulina, N-acetylcysteine, glucosamine sulfate potassium hydrochloride, trans-resveratrol, and maltodextrin-stabilized orthosilicic acid (SiliciuMax®). This review gives the scientific background on the hypothesis that these therapeutic agents can act in synergy in the prevention and improvement of COVID-19-associated symptoms.

Resveratrol can enhance osteogenic differentiation and mitochondrial biogenesis from human periosteum-derived mesenchymal stem cells

Background

Osteoporosis is a metabolic bone disorder that leads to low bone mass and microstructural deterioration of bone tissue and increases bone fractures. Resveratrol, a natural polyphenol compound, has pleiotropic effects including anti-oxidative, anti-aging, and anti-cancer effects. Resveratrol also has roles in increasing osteogenesis and in upregulating mitochondrial biogenesis of bone marrow-derived mesenchymal stem cells (BM-MSCs). However, it is still unclear that resveratrol can enhance osteogenic differentiation or mitochondrial biogenesis of periosteum-derived MSCs (PO-MSCs), which play key roles in bone tissue maintenance and fracture healing. Thus, in order to test a possible preventive or therapeutic effect of resveratrol on osteoporosis, this study investigated the effects of resveratrol treatments on osteogenic differentiation and mitochondrial biogenesis of PO-MSCs.

Methods

The optimal doses of resveratrol treatment on PO-MSCs were determined by cell proliferation and viability assays. Osteogenic differentiation of PO-MSCs under resveratrol treatment was assessed by alkaline phosphatase activities (ALP, an early biomarker of osteogenesis) as well as by extracellular calcium deposit levels (a late biomarker). Mitochondrial biogenesis during osteogenic differentiation of PO-MSCs was measured by quantifying both mitochondrial mass and mitochondrial DNA (mtDNA) contents.

Results

Resveratrol treatments above 10 μM seem to have negative effects on cell proliferation and viability of PO-MSCs. Resveratrol treatment (at 5 μM) on PO-MSCs during osteogenic differentiation increased both ALP activities and calcium deposits compared to untreated control groups, demonstrating an enhancing effect of resveratrol on osteogenesis. In addition, resveratrol treatment (at 5 μM) during osteogenic differentiation of PO-MSCs increased both mitochondrial mass and mtDNA copy numbers, indicating that resveratrol can bolster mitochondrial biogenesis in the process of PO-MSC osteogenic differentiation.

Conclusion

Taken together, the findings of this study describe the roles of resveratrol in promoting osteogenesis and mitochondrial biogenesis of human PO-MSCs suggesting a possible application of resveratrol as a supplement for osteoporosis and/or osteoporotic fractures.

Biphasic Dose-Response Induced by Phytochemicals: Experimental Evidence

Many phytochemicals demonstrate nonmonotonic dose/concentration-response termed biphasic dose-response and are considered to be hormetic compounds, i.e., they induce biologically opposite effects at different doses. In numerous articles the hormetic nature of phytochemicals is declared, however, no experimental evidence is provided. Our aim was to present the overview of the reports in which phytochemical-induced biphasic dose-response is experimentally proven. Hence, we included in the current review only articles in which the reversal of response between low and high doses/concentrations of phytochemicals for a single endpoint was documented. The majority of data on biphasic dose-response have been found for phytoestrogens; other reports described these types of effects for resveratrol, sulforaphane, and natural compounds from various chemical classes such as isoquinoline alkaloid berberine, polyacetylenes falcarinol and falcarindiol, prenylated pterocarpan glyceollin1, naphthoquinones plumbagin and naphazarin, and panaxatriol saponins. The prevailing part of the studies presented in the current review was performed on cell cultures. The most common endpoint tested was a proliferation of tumor and non-cancerous cells. Very few experiments demonstrating biphasic dose-response induced by phytochemicals were carried out on animal models. Data on the biphasic dose-response of various endpoints to phytochemicals may have a potential therapeutic or preventive implication.

Immunomodulatory and Metabolic Changes after Gnetin-C Supplementation in Humans

Gnetin-C is a naturally occurring stilbene derived from the seeds of Gnetum gnemon L., an edible plant native to Southeast Asia that is called melinjo. Although the biological properties and safety of G. gnemon extract, which contains nearly 3% Gnetin-C, have been confirmed in various human studies, whether or not pure Gnetin-C is safe for humans is unclear at present. We conducted a randomized, double-blind, placebo-controlled trial. Healthy subjects were randomly divided into two groups. The interventional group (n = 6) was given Gnetin-C, and the control group (n = 6) was provided a placebo, for 14 days. Lipid profiles, biomarkers of oxidative stress and circulating blood cells were assessed before and after the intervention. All subjects completed the study, with no side effects reported across the study duration. Gnetin-C supplementation demonstrated a statistically significant increase in the absolute number of circulating natural killer (NK) cells expressing the activating receptors NKG2D and NKp46. NK cells derived from subjects who received Gnetin-C for two weeks showed higher cytotoxicity against K562 target cells than those before receiving Gnetin-C. In addition, Gnetin-C also resulted in a significant decrease in the absolute neutrophil count in the blood compared with the placebo. Furthermore, Gnetin-C significantly reduced the levels of uric acid, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total adiponectin, and high-molecular-weight adiponectin. These data indicate that Gnetin-C has biological effects of enhancing the NK activity on circulating human immune cells. The immunomodulatory effects are consistent with a putative improvement in cancer immunosurveillance via the upregulation of the NKG2D receptor. The study was registered with UMIN-CTR, number 000030364, on 12 December 2017.

Resveratrol and Vascular Function

Resveratrol increases the production of nitric oxide (NO) in endothelial cells by upregulating the expression of endothelial NO synthase (eNOS), stimulating eNOS enzymatic activity, and preventing eNOS uncoupling. At the same time, resveratrol inhibits the synthesis of endothelin-1 and reduces oxidative stress in both endothelial cells and smooth muscle cells. Pathological stimuli-induced smooth muscle cell proliferation, vascular remodeling, and arterial stiffness can be ameliorated by resveratrol as well. In addition, resveratrol also modulates immune cell function, inhibition of immune cell infiltration into the vascular wall, and improves the function of perivascular adipose tissue. All these mechanisms contribute to the protective effects of resveratrol on vascular function and blood pressure in vivo. Sirtuin 1, AMP-activated protein kinase, and estrogen receptors represent the major molecules mediating the vascular effects of resveratrol.

Influence of Resveratrol on the Immune Response

Resveratrol is the most well-known polyphenolic stilbenoid, present in grapes, mulberries, peanuts, rhubarb, and in several other plants. Resveratrol can play a beneficial role in the prevention and in the progression of chronic diseases related to inflammation such as diabetes, obesity, cardiovascular diseases, neurodegeneration, and cancers among other conditions. Moreover, resveratrol regulates immunity by interfering with immune cell regulation, proinflammatory cytokines’ synthesis, and gene expression. At the molecular level, it targets sirtuin, adenosine monophosphate kinase, nuclear factor-κB, inflammatory cytokines, anti-oxidant enzymes along with cellular processes such as gluconeogenesis, lipid metabolism, mitochondrial biogenesis, angiogenesis, and apoptosis. Resveratrol can suppress the toll-like receptor (TLR) and pro-inflammatory genes’ expression. The antioxidant activity of resveratrol and the ability to inhibit enzymes involved in the production of eicosanoids contribute to its anti-inflammation properties. The effects of this biologically active compound on the immune system are associated with widespread health benefits for different autoimmune and chronic inflammatory diseases. This review offers a systematic understanding of how resveratrol targets multiple inflammatory components and exerts immune-regulatory effects on immune cells.

Role of Hedgehog Signaling in Breast Cancer: Pathogenesis and Therapeutics

Breast cancer (BC) is the leading cause of cancer-related mortality in women, only followed by lung cancer. Given the importance of BC in public health, it is essential to identify biomarkers to predict prognosis, predetermine drug resistance and provide treatment guidelines that include personalized targeted therapies. The Hedgehog (Hh) signaling pathway plays an essential role in embryonic development, tissue regeneration, and stem cell renewal. Several lines of evidence endorse the important role of canonical and non-canonical Hh signaling in BC. In this comprehensive review we discuss the role of Hh signaling in breast development and homeostasis and its contribution to tumorigenesis and progression of different subtypes of BC. We also examine the efficacy of agents targeting different components of the Hh pathway both in preclinical models and in clinical trials. The contribution of the Hh pathway in BC tumorigenesis and progression, its prognostic role, and its value as a therapeutic target vary according to the molecular, clinical, and histopathological characteristics of the BC patients. The evidence presented here highlights the relevance of the Hh signaling in BC, and suggest that this pathway is key for BC progression and metastasis.

Effect of Natural Compounds on NK Cell Activation

Natural killer (NK) cells are lymphocytes of the innate immune system that survey the body for stressed and abnormal cells. The integration of signals that they receive through various inhibitory and activating cell surface receptors controls their activation and ability to kill target cells and produce cytokines. In this manner, phenotypically and functionally distinct subsets of NK cells help protect against microbial infections and cancer and shape the adaptive immune response. NK cells can use two different mechanisms to kill their targets, either by cytotoxic granule exocytosis or by induction of death receptor-mediated apoptosis. Death ligands belong to the tumor necrosis factor (TNF) family of ligands. Upon release in close proximity to a cell slated for killing, perforin forms pores in the cell membrane of the target cell through which granzymes and associated molecules can enter and induce apoptosis. NK cells are also involved in antibody-dependent cellular toxicity via the CD16 receptor. In addition to target recognition, NK cells can be also activated by treatment with multiple compounds with stimulatory properties. Apart from interleukins, which belong to the best characterized group of NK cell-stimulating compounds, vitamins and constituents extracted from plants also display the ability to activate NK cells. The current review characterizes several groups of NK cell-activating compounds: vitamins belonging to classes A, B, C, D, and E, polysaccharides, lectins, and a number of phytochemicals used in cancer research, exhibiting stimulatory properties when applied to NK cells. Although in most cases the exact mechanism of action is not known, constituents described in this review seem to be promising candidates for NK cell-stimulating drugs.

Resveratrol Delivery from Porous Poly(lactide- co-glycolide) Scaffolds Promotes an Anti-Inflammatory Environment within Visceral Adipose Tissue

As biomaterial therapies emerge to address adipose tissue dysfunction that underlies metabolic disease, the immune response to these systems must be established. As a potential therapy, we are investigating resveratrol delivery from porous poly(lactide- co-glycolide) scaffolds designed to integrate with adipose tissue. Resveratrol was selected for its ability to protect mice and primates from high fat diet and broad anti-inflammatory properties. Herein, we report fabrication of scaffolds with high resveratrol loading that are stable and active for up to one year. In vitro release profiles indicate that drug release is biphasic with a burst release over 3 days followed by a plateau. Surprisingly, we find that PLG scaffolds implanted into adipose tissue of mice promote an anti-inflammatory environment characterized by high arginase-1 and low TNF-α and IL-6 compared to naïve unmanipulated fat. Resveratrol delivery from the scaffold augments this anti-inflammatory environment by decreasing monocyte and lymphocyte numbers at the implant site and increasing expression of IL-10 and IL-13, cytokines that promote healthy adipose tissue. In terms of therapeutic applications, implant of scaffolds designed to release resveratrol into the visceral fat decreases MCP-1 expression in mice fed a high fat diet, a molecule that drives both local and systemic inflammation during obesity. Taken together, resveratrol delivery to adipose tissue using poly(lactide- co-glycolide) scaffolds is a promising therapeutic strategy for the treatment of adipose tissue inflammation that drives metabolic disease.

The "Yin and Yang" of Natural Compounds in Anticancer Therapy of Triple-Negative Breast Cancers

Among the different types of breast cancers, triple-negative breast cancers (TNBCs) are highly aggressive, do not respond to conventional hormonal/human epidermal growth factor receptor 2 (HER2)-targeted interventions due to the lack of the respective receptor targets, have chances of early recurrence, metastasize, tend to be more invasive in nature, and develop drug resistance. The global burden of TNBCs is increasing regardless of the number of cytotoxic drugs being introduced into the market each year as they have only moderate efficacy and/or unforeseen side effects. Therefore, the demand for more efficient therapeutic interventions, with reduced side effects, for the treatment of TNBCs is rising. While some plant metabolites/derivatives actually induce the risk of cancers, many plant-derived active principles have gained attention as efficient anticancer agents against TNBCs, with fewer adverse side effects. Here we discuss the possible oncogenic molecular pathways in TNBCs and how the purified plant-derived natural compounds specifically target and modulate the genes and/or proteins involved in these aberrant pathways to exhibit their anticancer potential. We have linked the anticancer potential of plant-derived natural compounds (luteolin, chalcones, piperine, deguelin, quercetin, rutin, fisetin, curcumin, resveratrol, and others) to their ability to target multiple dysregulated signaling pathways (such as the Wnt/β-catenin, Notch, NF-κB, PI3K/Akt/mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (MAPK) and Hedgehog) leading to suppression of cell growth, proliferation, migration, inflammation, angiogenesis, epithelial-mesenchymal transition (EMT) and metastasis, and activation of apoptosis in TNBCs. Plant-derived compounds in combination with classical chemotherapeutic agents were more efficient in the treatment of TNBCs, possibly with lesser side effects.

The role of autophagy induction in the mechanism of cytoprotective effect of resveratrol

We aimed at studying the potential mechanisms in the preventive effect of resveratrol on serum deprivation induced caspase 3 activation on non-transformed cells.

METHODS

Apoptosis was induced by serum deprivation in primary mouse embryonic fibroblasts. Caspase 3 activation, reactive oxygen species production and depolarization of the mitochondrial membrane were measured by fluorescence methods. The involvement of intracellular receptors and autophagy in the effect of resveratrol were analyzed by using specific agonists and antagonists. The role of autophagy was further examined by Western Blot analysis of its protein markers, LC3-II and p62 as well as by acridine orange staining of acidic vacuoles.

RESULTS

We found that neither aromatic hydrocarbon receptors nor estrogen receptors play an important role in the cytoprotective effect of resveratrol. Reactive oxygen species production was not significantly altered by either serum deprivation or resveratrol treatment. In the presence of serum deprivation resveratrol however, induced a significant depolarization in mitochondrial membrane potential. The autophagy inhibitor, chloroquine not only eliminated the preventive effect of resveratrol, but also turned it to deleterious suggesting the prominent role of autophagy induction in the cytoprotective effect. Resveratrol did not alter LC3-II expression, but facilitated p62 degradation in serum deprived cells, suggesting its ability to augment the late phase of autophagy and thus promote the autophagic flux.

CONCLUSION

We have demonstrated that resveratrol can protect primary fibroblasts against serum deprivation induced apoptosis by provoking mild mitochondrial stress and consequent up-regulation of autophagic flux.

Polydatin, Natural Precursor of Resveratrol, Promotes Osteogenic Differentiation of Mesenchymal Stem Cells

Bone loss and fractures are consequences of aging, diseases or traumas. Furthermore the increased number of aged people, due to the rise of life expectancy, needs more strategies to limit the bone loss and regenerate the lost tissue, ameliorating the life quality of patients. A great interest for non-pharmacological therapies based on natural compounds is emerging and focusing on the oligostilbene Polydatin, present in many kinds of fruits and vegetables, when resveratrol particularly in red wines. These molecules have been extensively studied due to their antioxidant and anti-inflammatory effects, showing more recently Resveratrol the ability to enhance osteogenic differentiation and bone formation. However, the clinical applications of Resveratrol are limited due to its low bioavailability and rapid metabolism, while its natural glycosilated precursor Polydatin shows better metabolic stability and major abundance in fresh fruits and vegetables. Nevertheless the role of Polydatin on osteogenic differentiation is still unexplored. Mesenchymal stem cells (MSCs) from dental tissues, such as dental bud stem cells (DBSCs), are able to differentiate toward osteogenic lineage: thus we investigated how Resveratrol and Polydatin influence the differentiation of DBSCs, eventually affecting bone formation. Our results showed that Polydatin increases MSCs osteogenic differentiation sharing similar properties with Resveratrol. These results encourage to deepen the effects of this molecule on bone health and its associated mechanisms of action, wishing for the future a successful use in bone loss prevention and therapy.

Biological effects of combined resveratrol and vitamin D3 on ovarian tissue

BACKGROUND

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural antioxidant polyphenol able to exert a wide range of biological effect on several tissues. Despite its important beneficial properties, it has a low water solubility, which limits its therapeutic applications in humans. Resveratrol also acts as a phytoestrogen that modulates estrogen receptor (ER)-mediated transcription. In addition, it has been shown that ovarian tissues benefit greatly from vitamin D3, which exerts its beneficial effects through VDR receptors. The aim was to evaluate the cooperative effects of resveratrol combined with vitamin D3 on ovarian cells and tissues and some other organs as well. Moreover, the modulation of specific intracellular pathways involving ER and VDR receptors has been studied.

METHODS

The experiments were performed both in vitro and in vivo, to analyze cell viability, radical oxygen species production, signal transductions through Western Blot, and resveratrol quantification by HPLC.

RESULTS

Cell viability, radical oxygen species production, and intracellular pathways have been studied on CHO-K1 cells. Also, the relative mechanism activated following oral intake in female Wistar rats as animal model was investigated, evaluating bioavailability, biodistribution and signal transduction in heart, kidney, liver and ovarian tissues. Both in in vitro and in vivo experiments, resveratrol exerts more evident effects when administered in combination with vitD in ovarian cells, showing a common biphasic cooperative effect: The role of vitamin D3 in maintaining and supporting the biological activity of resveratrol has been clearly observed. Moreover, resveratrol plus vitamin D3 blood concentrations showed a biphasic absorption rate.

CONCLUSIONS

Such results could be used as a fundamental data for the development of new therapies for gynecological conditions, such as hot-flashes.

Simulated microgravity affects some biological characteristics of Lactobacillus acidophilus

The effects of weightlessness on enteric microorganisms have been extensively studied, but have mainly been focused on pathogens. As a major component of the microbiome of the human intestinal tract, probiotics are important to keep the host healthy. Accordingly, understanding their changes under weightlessness conditions has substantial value. This study was carried out to investigate the characteristics of Lactobacillus acidophilus, a typical probiotic for humans, under simulated microgravity (SMG) conditions. The results revealed that SMG had no significant impact on the morphology of L. acidophilus, but markedly shortened its lag phase, enhanced its growth rate, acid tolerance ability up to pH < 2.5, and the bile resistance at the bile concentration of <0.05%. SMG also decreased the sensitivity of L. acidophilus to cefalexin, sulfur gentamicin, and sodium penicillin. No obvious effect of SMG was observed on the adhesion ability of L. acidophilus to Caco-2 cells. Moreover, after SMG treatment, both the culture of L. acidophilus and its liquid phase exhibited higher antibacterial activity against S. typhimurium and S. aureus in a time-dependent manner. The SMG treatment also increased the in vitro cholesterol-lowering ability of L. acidophilus by regulating the expression of the key cholesterol metabolism genes CYP7A1, ABCB11, LDLR, and HMGCR in the HepG2 cell line. Thus, the SMG treatment did have considerable influence on some biological activities and characteristics of L. acidophilus related to human health. These findings provided valuable information for understanding the influence of probiotics on human health under simulated microgravity conditions, at least.

NK cells contribute to persistent airway inflammation and AHR during the later stage of RSV infection in mice

RSV can lead to persistent airway inflammation and AHR and is intimately associated with childhood recurrent wheezing and asthma, but the underlying mechanisms remain unclear. There are high numbers of NK cells in the lung, which not only play important roles in the acute stage of RSV infection, but also are pivotal in regulating the pathogenesis of asthma. Therefore, in this study, we assumed that NK cells might contribute to persistent airway disease during the later stage of RSV infection. Mice were killed at serial time points after RSV infection to collect samples. Leukocytes in bronchoalveolar lavage fluid (BALF) were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. Cytokines were detected by ELISA, and NK cells were determined by flow cytometry. Rabbit anti-mouse asialo-GM-1 antibodies and resveratrol were used to deplete or suppress NK cells. Inflammatory cells in BALF, lung tissue damage and AHR were persistent for 60 days post-RSV infection. Type 2 cytokines and NK cells were significantly increased during the later stage of infection. When NK cells were decreased by the antibodies or resveratrol, type 2 cytokines, the persistent airway inflammation and AHR were all markedly reduced. NK cells can contribute to the RSV-associated persistent airway inflammation and AHR at least partially by promoting type 2 cytokines. Therefore, therapeutic targeting of NK cells may provide a novel approach to alleviating the recurrent wheezing subsequent to RSV infection.

Nutritional immunology: function of natural killer cells and their modulation by resveratrol for cancer prevention and treatment

Natural killer (NK) cells as part of the innate immune system represent the first line of defence against (virus-) infected and malignantly transformed cells. The emerging field of nutritional immunology focuses on compounds featuring immune-modulating activities in particular on NK cells, which e.g. can be exploited for cancer prevention and treatment. The plant-based nutrition resveratrol is a ternary hydroxylated stilbene, which is present in many foods and beverages, respectively. In humans it comprises a large variety of distinct biological activities. Interestingly, resveratrol strongly modulates the immune response including the activity of NK cells. This review will give an overview on NK cell functions and summarize the resveratrol-mediated modulation thereof.

A multi-targeted approach to suppress tumor-promoting inflammation

Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes.

Protective effect of resveratrol against caspase 3 activation in primary mouse fibroblasts

Aim

To study the effect of resveratrol on survival and caspase 3 activation in non-transformed cells after serum deprivation.

Methods

Apoptosis was induced by serum deprivation in primary mouse embryonic fibroblasts. Caspase 3 activation and lactate dehydrogenase release were assayed as cell viability measure by using their fluorogenic substrates. The involvement of PI3K, ERK, JNK, p38, and SIRT1 signaling pathways was also examined.

Results

Serum deprivation of primary fibroblasts induced significant activation of caspase 3 within 3 hours and reduced cell viability after 24 hours. Resveratrol dose-dependently prevented caspase activation and improved cell viability with 50% inhibitory concentration (IC₅₀) = 66.3 ± 13.81 µM. It also reduced the already up-regulated caspase 3 activity when it was added to the cell culture medium after 3 hour serum deprivation, suggesting its rescue effect. Among the major signaling pathways, p38 kinase was critical for the protective effect of resveratrol which was abolished completely in the presence of p38 inhibitor.

Conclusion

Resveratrol showed protective effect against cell death in a rather high dose. Involvement of p38 kinase in this effect suggests the role of mild stress in its cytoprotective action. Furthermore due to its rescue effect, resveratrol may be used not only for prevention, but also treatment of age-related degenerative diseases, but in the higher dose than consumed in conventional diet.