Unripe Black Raspberry (Rubus coreanus Miquel) Extract and Its Constitute, Ellagic Acid Induces T Cell Activation and Antitumor Immunity by Blocking PD-1/PD-L1 Interaction

Caryophylli Cortex Suppress PD-L1 Expression in Cancer Cells and Potentiates Anti-Tumor Immunity in a Humanized PD-1/PD-L1 Knock-In MC-38 Colon Cancer Mouse Model

BACKGROUND/OBJECTIVES

Immune checkpoints are essential for regulating excessive autoimmune responses and maintaining immune homeostasis. However, in the tumor microenvironment, these checkpoints can lead to cytotoxic T cell exhaustion, allowing cancer cells to evade immune surveillance and promote tumor progression. The expression of programmed death-ligand 1 (PD-L1) in cancer cells is associated with poor prognoses, reduced survival rates, and lower responses to therapies. Consequently, downregulating PD-L1 expression has become a key strategy in developing immune checkpoint inhibitors (ICIs). Caryophylli cortex (CC), derived from the bark of the clove tree Syzygium aromaticum, possesses antioxidant and cytotoxic properties against cancer cells, yet its potential as an ICI remains unclear.

METHODS

In this study, we aimed to investigate whether CC extract modulates PD-L1 expression in cancer cells and activates T cell immunity through a co-culture system of cancer cells and T cells, as well as in hPD-L1/MC-38 tumor-bearing animal models.

RESULTS

Our findings indicate that CC extract significantly downregulated both constitutive and inducible PD-L1 expression at non-toxic concentrations for cancer cells while simultaneously enhancing cancer cell mortality and T cell activity in the co-culture system. Furthermore, the administration of CC extract to hPD-L1/MC-38 tumor-bearing mice resulted in a greater than 70% reduction in tumor growth and increased infiltration of CD8+ T cells within the tumor microenvironment. Principal component analysis identified bergenin, chlorogenic acid, and ellagic acid as active ICIs.

CONCLUSIONS

These findings suggest that CC extract exerts a potent antitumor effect as an immune checkpoint blocker by inhibiting PD-L1 expression in cancer cells and disrupting the PD-1/PD-L1 interaction.

Comparison of "framework Shuffling" and "CDR Grafting" in humanization of a PD-1 murine antibody

Introduction

Humanization is typically adopted to reduce the immunogenicity of murine antibodies generated by hybridoma technology when used in humans.

Methods

Two different strategies of antibody humanization are popularly employed, including "complementarity determining region (CDR) grafting" and "framework (FR) shuffling" to humanize a murine antibody against human programmed death-1 (PD-1), XM PD1. In CDR-grafting humanization, the CDRs of XM PD-1, were grafted into the human FR regions with high homology to the murine FR counterparts, and back mutations of key residues were performed to retain the antigen-binding affinities. While in FR-shuffling humanization, a combinatorial library of the six murine CDRs in-frame of XM PD-1 was constructed to a pool of human germline FRs for high-throughput screening for the most favorable variants. We evaluated many aspects which were important during antibody development of the molecules obtained by the two methods, including antibody purity, thermal stability, binding efficacy, predicted humanness, and immunogenicity, along with T cell epitope prediction for the humanized antibodies.

Results

While the ideal molecule was not achieved through CDR grafting in this particular instance, FR-shuffling proved successful in identifying a suitable candidate. The study highlights FR-shuffling as an effective complementary approach that potentially increases the success rate of antibody humanization. It is particularly noted for its accessibility to those with a biological rather than a computational background.

Discussion

The insights from this comparison are intended to assist other researchers in selecting appropriate humanization strategies for drug development, contributing to broader application and understanding in the field.

Chemical composition, pharmacological activity and development strategies of Rubus chingii: A review

Raspberries are used for both food and medicine, but it has not yet attracted widespread attention. In this paper, the chemical constituen of the original plant raspberry. R. chingii is one of the new "Zhe Bawei" medicinal materials selected in 2017. "Zhe Bawei" refers to eight kinds of genuine medicinal materials in Zhejiang Province. The chemical constituents, pharmacological effects, processing, and application of Rubus chingii Hu were reviewed to provide a reference for its further development. Relevant literature in recent years was collected in databases such as China Knowledge Network, Web of Science, Elsevier, PubMed, and X-Mol, using "raspberry", "Rubus chingii", "traditional use", "chemical composition", "pharmacology", etc. as keywords individually or in combination. The summary of pharmacological activities shows that the relationship between the pharmacological activities of raspberry is still not deep enough. More in-depth research should be carried out in this direction to explore the mechanism of action of its active ingredients and provide effective reference for the further development of the raspberry industry. In the future, with the participation of more researchers, it is expected to develop innovative drugs based on raspberry for the treatment of diseases.

The role of CD8+ T-cells in colorectal cancer immunotherapy

Immunotherapy has been an advanced and effective approach to treating various types of solid tumors in recent years, and the most successful strategy is immune checkpoint inhibitors (ICIs), which have shown beneficial effects in patients with colorectal cancer (CRC). Drug resistance to ICIs is usually associated with CD8+ T-cells targeting tumor antigens; thus, CD8+ T-cells play an important role in immunotherapy. Unfortunately, Under continuous antigen stimulation, tumor microenvironment(TME), hypoxia and other problems it leads to insufficient infiltration of CD8+ T-cells, low efficacy and mechanism exhaustion, which have become obstacles to immunotherapy. Thus, this article describes the relationship between CRC and the immune system, focuses on the process of CD8+ T-cells production, activation, transport, killing, and exhaustion, and expounds on related mechanisms leading to CD8+ T-cells exhaustion. Finally, this article summarizes the latest strategies and methods in recent years, focusing on improving the infiltration, efficacy, and exhaustion of CD8+ T-cells, which may help to overcome the barriers to immunotherapy.

Rubus Occidentalis and its bioactive compounds against cancer: From molecular mechanisms to translational advances

BACKGROUND

Cancer ranks as the second leading cause of death globally, imposing a significant public health burden. The rise in cancer resistance to current therapeutic agents underscores the potential role of phytotherapy. Black raspberry (BRB, Rubus Occidentalis) is a fruit rich in anthocyanins, ellagic acid, and ellagitannins. Accumulating evidence suggests that BRB exhibits promising anticancer effects, positioning it as a viable candidate for phytotherapy.

PURPOSE

This article aims to review the existing research on BRB regarding its role in cancer prevention and treatment. It further analyzes the effective components of BRB, their metabolic pathways, and the potential mechanisms underlying the fruit's anticancer effects.

METHODS

Ovid MEDLINE, EMBASE, Web of Science, and CENTRAL were searched through the terms of Black Raspberry, Raspberry, and Rubus Occidentali up to January 2023. Two reviewers performed the study selection by screening the title and abstract. Full texts of potentially eligible studies were retrieved to access the details.

RESULTS

Out of the 767 articles assessed, 73 papers met the inclusion criteria. Among them, 63 papers investigated the anticancer mechanisms, while 10 conducted clinical trials focusing on cancer treatment or prevention. BRB was found to influence multiple cancer hallmarks by targeting various pathways. Decomposition of free radicals and regulation of estrogen metabolism, BRB can reduce DNA damage caused by reactive oxygen species. BRB can also enhance the function of nucleotide excision repair to repair DNA lesions. Through regulation of epigenetics, BRB can enhance the expression of tumor suppressor genes, inducing cell cycle arrest, and promoting apoptosis and pyroptosis. BRB can reduce the energy and nutrients supply to the cancer nest by inhibiting glycolysis and reducing angiogenesis. The immune and inflammatory microenvironment surrounding cancer cells can also be ameliorated by BRB, inhibiting cancer initiation and progression. However, the limited bioavailability of BRB diminishes its anticancer efficacy. Notably, topical applications of BRB, such as gels and suppositories, have demonstrated significant clinical benefits.

CONCLUSION

BRB inhibits cancer initiation, progression, and metastasis through diverse anticancer mechanisms while exhibiting minimal side effects. Given its potential, BRB emerges as a promising phototherapeutic agent for cancer treatment.

Ellagic acid inhibits tumor growth and potentiates the therapeutic efficacy of sorafenib in hepatocellular carcinoma

Background

Sorafenib is a classic molecular targeted drug approved for hepatocellular carcinoma (HCC) therapy. However, a poor response rate and increasing resistance to sorafenib make its therapeutic efficacy suboptimal. Combination treatment with an agent capable of potentiating sorafenib sensitivity may be a promising solution.

Aim

The aim of this study was to determine the synergistic effect of ellagic acid (EA), a natural polyphenol, and sorafenib on HCC.

Methods

CCK-8, EdU incorporation and colony formation assays were used to study the effect of EA on HCC cell proliferation. Apoptosis was detected by flow cytometry in HCC cells and TUNEL assay in xenograft tumors. Transcriptome analysis was utilized to investigate alterations in signaling pathways with EA treatment. A xenograft mouse model was used to confirm the synergistic effect of sorafenib and EA on HCC tumors in vivo.

Results

We found that EA inhibited growth and induced apoptosis in both HCC cells and xenograft tumors. Mechanistically, EA treatment reduced the activation of the MAPK and Akt/mTOR signaling pathways in HCC cells. Furthermore, combined EA and sorafenib treatment further inhibited the MAPK and Akt/mTOR signaling pathways compared to EA or sorafenib alone. EA synergistically potentiated the anticancer activity of sorafenib against HCC both in vitro and in vivo.

Conclusion

EA inhibits HCC growth by inducing apoptosis through attenuation of the MAPK and Akt/mTOR signaling pathways. EA potentiates the response of HCC tumors to sorafenib both in vitro and in vivo, an effect that may be attributed to further inhibition of the MAPK and Akt/mTOR signaling pathways. These results suggest that EA is an effective adjuvant option for sorafenib therapy.

Ellagic Acid and Cancer Hallmarks: Insights from Experimental Evidence

Cancer is a complex and multifaceted disease with a high global incidence and mortality rate. Although cancer therapy has evolved significantly over the years, numerous challenges persist on the path to effectively combating this multifaceted disease. Natural compounds derived from plants, fungi, or marine organisms have garnered considerable attention as potential therapeutic agents in the field of cancer research. Ellagic acid (EA), a natural polyphenolic compound found in various fruits and nuts, has emerged as a potential cancer prevention and treatment agent. This review summarizes the experimental evidence supporting the role of EA in targeting key hallmarks of cancer, including proliferation, angiogenesis, apoptosis evasion, immune evasion, inflammation, genomic instability, and more. We discuss the molecular mechanisms by which EA modulates signaling pathways and molecular targets involved in these cancer hallmarks, based on in vitro and in vivo studies. The multifaceted actions of EA make it a promising candidate for cancer prevention and therapy. Understanding its impact on cancer biology can pave the way for developing novel strategies to combat this complex disease.

Efficacy and mechanism of Wuzi Yanzong pill on the prevention and treatment of EAE

Objective

Studies have shown that Wuzi Yanzong Pill (WYP) can be used to treat neurological diseases, but its mechanisms for multiple sclerosis (MS) remain unclear. This study aims to determine the effect of WYP on MS in an animal model of experimental autoimmune encephalomyelitis (EAE), and explore its mechanism. To provide theoretical basis for the clinical treatment of MS with WYP.

Methods

C57BL/6 female mice were randomly divided into Blank control, EAE control, low dose WYP, medium dose WYP, and high dose WYP groups. One week before model generation, the mice were gavaged with saline (50 mL/kg/d) in Blank control and EAE control groups. The treatment groups was gavaged with different doses of WYP solution (4, 8, or 16 g/kg/d respectively) Clinical scores were recorded daily. Sample collection was conducted on the 14th and 28th days, respectively The expressions of IL-10, IL-17, IL-12, TNF-α and IFN-γ in spleen were detected by ELISA. The expressions of ROCKII, P-MYPT1, TLR4, NF-κB/p65, MCP-1, CCR2 in spleen, brain and spinal cord were detected by Western Blot. The types of macrophages and the contents of intracellular IL-10 and IL-12 were detected by Flow Cytometry. The contents of TNF-α and TLR4 mRNA in the spleen were detected by RT-PCR.

Results

WYP treatment improved the clinical score of EAE mice in a significant dose-dependent manner, with the WYP high-dose group showed the most significant improvement in clinical score. Compared with the EAE control group, WYP high dose group had significantly lower levels of IL-17, IFN-γ, ROCKII, P-MYPT1, TLR4, NF-κB/p65, MCP-1, and CCR2 as well as TNF-α and TLR4 mRNA, but increased the number of M2 macrophages and IL-10.

Conclusion

WYP treatment relieves clinical symptoms in EAE mice, which may be related to regulate inflammatory pathway and inhibiting expressions of inflammatory cytokines.

Natural Blockers of PD-1/PD-L1 Interaction for the Immunotherapy of Triple-Negative Breast Cancer-Brain Metastasis

The limited treatment options for triple-negative breast cancer with brain metastasis (TNBC-BM) have left the door of further drug development for these patients wide open. Although immunotherapy via monoclonal antibodies has shown some promising results in several cancers including TNBC, it cannot be considered the most effective treatment for brain metastasis. This is due to the protective role of the blood-brain barrier (BBB) which limits the entrance of most drugs, especially the bulky ones such as antibodies, to the brain. For a drug to traverse the BBB via passive diffusion, various physicochemical properties should be considered. Since natural medicine has been a key inspiration for the development of the majority of current medicines, in this paper, we review several naturally-derived molecules which have the potential for immunotherapy via blocking the interaction of programmed cell death protein-1 (PD-1) and its ligand, PD-L1. The mechanism of action, physicochemical properties and pharmacokinetics of these molecules and their theoretical potential to be used for the treatment of TNBC-BM are discussed.

Augmented Antitumor Effect of Unripe Rubus coreanus Miquel Combined with Oxaliplatin in a Humanized PD-1/PD-L1 Knock-In Colorectal Cancer Mouse Model

Immune checkpoint inhibitors (ICIs) have been shown to be extraordinarily effective in patients with colorectal cancer (CRC). However, the current ICIs still have adverse effects and limited efficacy of ICI monotherapy. We used a natural product to overcome the vulnerability of ICIs and tried a combination therapy with oxaliplatin to enhance the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) blockade anticancer effect. In the present study, we evaluated the T cell-mediated antitumor immunity with Unripe Rubus coreanus Miquel extract (RCE), which exerts anticancer properties via PD-1/PD-L1 blockade, combined with oxaliplatin in a co-culture cell model and allograft tumor humanized PD-1 mice. We found that RCE plus oxaliplatin apparently activates hPD-1 tumor-infiltrating CD8+ T cells, resulting in elevations of released interleukin-2 (IL-2) and granzyme B (GrB), and kills hPD-L1 MC38 CRC cells. RCE plus oxaliplatin considerably reduced tumor growth in humanized PD-1/PD-L1-expressing mouse MC38 CRC allograft. Moreover, RCE plus oxaliplatin remarkably increased the infiltration of CD8+ T cells in tumor tissues, as well as increasingly produced GrB of tumor-infiltrating CD8+ T cells in the tumor microenvironment. Our study delineated combination therapy with RCE as a PD-1/PD-L1 blockade and oxaliplatin to improve the response to immune checkpoint blockade therapy in conjunction with standard chemotherapy regimens in CRC.

Synergistic effects of novel herbal decoctions from Panax ginseng and Morus alba on tyrosinase activity and melanogenesis in vitro

Many medicinal plants such as a Panax ginseng and Morus alba (mulberry tree) have been widely used as depigmenting agents in Asia. To maximize their synergistic effects on melanogenesis, new herbal decoctions were created by mixing Ginseng Radix Alba (GR) and Mori Radicis Cortex (MC) at a ratio of 3:2 which called GMC decoction. A decoction of GR and Mori Ramulus (MR), which called GMR, was also formulated in order to compare the anti-melanogenic capacity. Combined decoctions, GMC and GMR, significantly decreased mushroom tyrosinase activity in vitro; however, single extracts, including MC and MR, showed weaker inhibitory activity. Melanin content assay and Fontana–Masson staining confirmed that two decoctions showed stronger inhibitory effects on the forskolin-induced melanin level in B16 cells, without cytotoxicity. Our findings suggest that ginseng in combination with mulberry tree enhances the anti-melanogenic effect in vitro.

SR-5, the specific ratio of Korean multi-herbal formula: An evaluation of antiulcerogenic effects on experimentally induced gastric ulcers in mice

Purpose

Previously, we demonstrated that the specific ratio of Korean multi-herbal formula (SR-5) exhibits hepatoprotective properties against ethanol-induced hepatic damage in rats. Chronic and excessive alcohol consumption is a major etiological factor involved in gastric disease and ulcer development induced by the inflammatory response and oxidative stress.

Methods

The present study evaluated the gastroprotective effects of SR-5 (100, 150, and 200 mg/kg) against hydrochloride acid/ethanol (HCl/EtOH)-induced and indomethacin/hydrochloride acid (INDO/HCl)-induced gastritis in a mouse model and the mechanisms involved.

Results

All the tested doses of SR-5 significantly inhibited gastric lesions in the HCl/EtOH-induced ulcer model mice. Similarly, all the tested doses of SR-5 significantly inhibited gastric lesions in the INDO/HCl-induced ulcer model mice. Furthermore, mice pretreated with SR-5 had significantly increased gastric levels of enzymatic and nonenzymatic antioxidants, namely, catalase (CAT) and glutathione (GSH), with concomitant reductions in malondialdehyde (MDA) and reactive oxygen species (ROS) levels compared with those in the HCl/EtOH or INDO/HCl group. SR-5 suppressed the expression of nuclear factor-kappa B (NF-κB)/p65, inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) to their normal values.

Conclusion

These findings are the first to demonstrate the powerful protective effect of SR-5 against gastric injury development and provide hope for clinical application.

The Separation and Purification of Ellagic Acid from Phyllanthus urinaria L. by a Combined Mechanochemical-Macroporous Resin Adsorption Method

Ellagic acid is a phenolic compound that exhibits both antimutagenic and anticarcinogenic activity in a wide range of assays in vitro and in vivo. It occurs naturally in some foods such as raspberries, strawberries, grapes, and black currants. In this study, a valid and reliable method based on mechanochemical-assisted extraction (MCAE) and macroporous adsorption resin was developed to extract and prepare ellagic acid from Phyllanthus urinaria L. (PUL). The MCAE parameters, acidolysis, and macroporous adsorption resin conditions were investigated. The key MCAE parameters were optimized as follows: the milling time was 5 min, the ball mill speed was 100 rpm, and the ball mill filling rate was 20.9%. Sulfuric acid with a concentration of 0.552 mol/L was applied for the acidolysis with the optimized acidolysis time of 30 min and acidolysis temperature of 40 °C. Additionally, the XDA-8D macroporous resin was chosen for the purification work. Both the static and dynamic adsorption tests were carried out. Under the optimized conditions, the yield of ellagic acid was 10.2 mg/g, and the content was over 97%. This research provided a rapid and efficient method for the preparation of ellagic acid from the cheaply and easily obtained PUL. Meanwhile, it is relatively low-cost work that can provide a technical basis for the comprehensive utilization of PUL.

Sanguisorbae Radix Suppresses Colorectal Tumor Growth Through PD-1/PD-L1 Blockade and Synergistic Effect With Pembrolizumab in a Humanized PD-L1-Expressing Colorectal Cancer Mouse Model

Immune checkpoints such as programmed death-1 (PD-1) have been proven as antitumor targets by enhancing cytotoxic T cell activity. All immune checkpoint blockades are antibody therapeutics that have large size and high affinity, as well as known immune-related side effects and low responses. To overcome the limitation of antibody therapeutics, we have explored PD-1/PD-L1 (programmed death-ligand 1) blockades in traditional oriental medicine, which has a long history but has not yet studied PD-1/PD-L1 blockades. Sanguisorbae Radix extract (SRE) blocked PD-1 and PD-L1 binding in competitive ELISA. SRE effectively inhibited the PD-1/PD-L1 interaction, thereby improving T cell receptor (TCR) signaling and the NFAT-mediated luciferase activity of T cells. SRE treatment reduced tumor growth in the humanized PD-L1 MC38 cell allograft humanized PD-1 mouse model. Additionally, the combination of SRE and pembrolizumab (anti-PD-1 antibody) suppressed tumor growth and increased infiltrated cytotoxic T cells to a greater extent did either agent alone. This study showed that SRE alone has anticancer effects via PD-1/PD-L1 blockade and that the combination therapy of SRE and pembrolizumab has enhanced immuno-oncologic effects.

Small molecule inhibitors against PD-1/PD-L1 immune checkpoints and current methodologies for their development: a review

Programmed death-1/programmed death ligand-1 (PD-1/PD-L1) based immunotherapy is a revolutionary cancer therapy with great clinical success. The majority of clinically used PD-1/PD-L1 inhibitors are monoclonal antibodies but their applications are limited due to their poor oral bioavailability and immune-related adverse effects (irAEs). In contrast, several small molecule inhibitors against PD-1/PD-L1 immune checkpoints show promising blockage effects on PD-1/PD-L1 interactions without irAEs. However, proper analytical methods and bioassays are required to effectively screen small molecule derived PD-1/PD-L1 inhibitors. Herein, we summarize the biophysical and biochemical assays currently employed for the measurements of binding capacities, molecular interactions, and blocking effects of small molecule inhibitors on PD-1/PD-L1. In addition, the discovery of natural products based PD-1/PD-L1 antagonists utilizing these screening assays are reviewed. Potential pitfalls for obtaining false leading compounds as PD-1/PD-L1 inhibitors by using certain binding bioassays are also discussed in this review.