Functional Regulation of Ginsenosides on Myeloid Immunosuppressive Cells in the Tumor Microenvironment

20(S)-ginsenoside Rg3 alleviates DSS-induced colitis by promoting ERK-dependent maturation of MDSCs into M2 macrophages

Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells with immunosuppressive functions that play various roles in tumors and inflammatory diseases. In colitis, MDSCs accumulate in the inflamed colon, where they mature into M2-polarized macrophages and modulate inflammatory responses. Ginsenosides, active components of ginseng, have been shown to display colitis-alleviating effects in mouse models. However, the detailed mechanisms underlying these effects are incompletely understood. This study explores the impact of ginsenosides on MDSC functions and differentiation, focusing on their potential to mitigate inflammatory symptoms in colitis. Among the 15 ginsenosides tested, Rg3(R) and Rg3(S) were found to promote the maturation of MDSCs into M2 macrophages at non-cytotoxic concentrations. This was confirmed by the increased expression of ARG1, an immunosuppressive marker. These effects were attributed to the activation of the ERK pathway, as confirmed by selective ERK inhibition. In a DSS-induced colitis mouse model, oral administration of Rg3(S) alleviated disease severity and increased MDSC differentiation into M2 macrophages in colon lamina propria, highlighting its therapeutic potential colitis.

Low-Medium Polarity Ginsenosides from Wild Ginseng Improves Immunity by Activating the AhR/MAPK Pathway through Tryptophan Metabolism Driven by Gut Microbiota

The gut microbiota contribute significantly to the immune system. Low-medium polarity ginsenosides from wild ginseng (LWG) have potential immunomodulatory effects. However, how the LWG regulates gut microbiota to enhance immunity remains unclear. To explore the interaction between gut microbes and metabolites mediating LWG's immunomodulatory effects, this study examined LWG's impact on splenocytes and CTX-induced immunosuppressed mice. Metabolomic and metagenomic analyses were conducted in vivo to explore the mechanism by which LWG regulates gut microbiota to enhance immunity. In vitro data suggest that LWG at 4 μg/mL enhances the splenocyte activity. Furthermore, LWG effectively reduces symptoms in immunocompromised mice, including weight loss and intestinal mucosal damage. LWG alleviated gut microbiota disturbance, restored tryptophan metabolites (IA, IAA, and IPA), and significantly increased JNK, ERK, and p38MAPK protein levels, which were downstream of AhR. Our study demonstrated that LWG improves the immunity by reshaping gut microbiota, restoring intestinal mucosa, and boosting the gut microbiota-related metabolism of tryptophan to activate the AhR/MAPK pathway. This research offers new insights into the mechanism by which LWG regulates immune function.

Targeting CD8+ T cells with natural products for tumor therapy: Revealing insights into the mechanisms

BACKGROUND

Despite significant advances in cancer immunotherapy over the past decades, such as T cell-engaging chimeric antigen receptor (CAR)-T cell therapy and immune checkpoint blockade (ICB), therapeutic failure resulting from various factors remains prevalent. Therefore, developing combinational immunotherapeutic strategies is of great significance for improving the clinical outcome of cancer immunotherapy. Natural products are substances that naturally exist in various living organisms with multiple pharmacological or biological activities, and some of them have been found to have anti-tumor potential. Notably, emerging evidences have suggested that several natural compounds may boost the anti-tumor effects through activating immune response of hosts, in which CD8+ T cells play a pivotal role.

METHODS

The data of this review come from PubMed, Web of Science, Google Scholar, and ClinicalTrials (https://clinicaltrials.gov/) with the keywords "CD8+ T cell", "anti-tumor", "immunity", "signal 1", "signal 2", "signal 3", "natural products", "T cell receptor (TCR)", "co-stimulation", "co-inhibition", "immune checkpoint", "inflammatory cytokine", "hesperidin", "ginsenoside", "quercetin", "curcumin", "apigenin", "dendrobium officinale polysaccharides (DOPS)", "luteolin", "shikonin", "licochalcone A", "erianin", "resveratrol", "procyanidin", "berberine", "usnic acid", "naringenin", "6-gingerol", "ganoderma lucidum polysaccharide (GL-PS)", "neem leaf glycoprotein (NLGP)", "paclitaxel", "source", "pharmacological activities", and "toxicity". These literatures were published between 1993 and 2023.

RESULTS

Natural products have considerable advantages as anti-tumor drugs based on the various species, wide distribution, low price, and few side effects. This review summarized the effects and mechanisms of some natural products that exhibit anti-tumor effects via targeting CD8+ T cells, mainly focused on the three signals that activate CD8+ T cells: TCR, co-stimulation, and inflammatory cytokines.

CONCLUSION

Clarifying the role and underlying mechanism of natural products in cancer immunotherapy may provide more options for combinational treatment strategies and benefit cancer therapy, to shed light on identifying potential natural compounds for improving the clinical outcome in cancer immunotherapy.

Crocin's effect on phenotype switching of J774A.1 macrophages depends on their polarization state during exposure

Objectives

Macrophages exhibit versatile phenotypes, with M1 macrophages releasing inflammatory cytokines and possessing microbicidal activities, while M2 macrophages release anti-inflammatory cytokines and contribute to tissue repair. The M1/M2 imbalance plays a significant role in various pathological processes. Crocin, known for its antioxidant properties and ability to eliminate free radicals, has been investigated for its potential anti-inflammatory effects. We examined the effect of the primary activation state of macrophages on their phenotype switching when exposed to crocin.

Materials and Methods

The crocin impact on macrophage viability was evaluated by MTT. TNF-α, IL-6, and IL-10 secretion, as well as Nos2/Arg1 ratio, were measured in cells treated with crocin or LPS+IFN-γ (M1 inducers), in cells concurrently treated with crocin and LPS+IFN-γ or in cells pretreated with crocin before M1 induction.

Results

Crocin did not show any toxicity at the concentration of 500 µM or lower. When uncommitted macrophages were exposed to crocin (25-100 µM), it elevated certain M1 activity indicators, including Nos2/Arg1 ratio and TNF-α secretion, but not IL-6. Crocin in concurrent treatment with LPS+IFN-γ prevented the increase in M1 indicators, Nos2/Arg1 ratio, and TNF-α secretion. However, pretreatment of cells with crocin before the addition of LPS+IFN-γ did not reverse M1 induction in macrophages; instead, it further increased the Nos2/Arg1 ratio and TNF-α secretion. IL-10 was not detectable in any of the experimental groups.

Conclusion

It appears that the modulatory effects of crocin on macrophage M1/M2 phenotype switching partly depend on the presence or absence of inflammatory mediators and, accordingly, the initial state of macrophage commitment.

Bojungikki-Tang Improves Response to PD-L1 Immunotherapy by Regulating the Tumor Microenvironment in MC38 Tumor-Bearing Mice

Immune checkpoint blockage targeting PD-L1 has led to breakthroughs in cancer treatment. Although anti-PD-L1-based immunotherapy has been approved as standard therapy in various cancer types, its therapeutic efficacy in most colorectal cancers (CRC) is still limited due to the low response to immunotherapy. Therefore, combining treatment with herbal medicines could be an alternative approach for treating CRC to overcome this limitation. Bojungikki-Tang (BJIKT), a herbal formula used in traditional Chinese medicine, clinically improves the quality of life for cancer patients and has been associated with antitumor and immune-modulating activities. However, the regulatory effect of BJIKT on the immune response in the tumor microenvironment remains largely uninvestigated. In this study, we verified the inhibitory effect of BJIKT on tumor growth and investigated the regulatory effect of combination therapy with BJIKT and anti-PD-L1 on antitumor immune responses in an MC38 CRC-bearing C57BL/6 mouse model. Immune profiling analysis by flow cytometry was used to characterize the exact cell types contributing to anticancer activities. Combination treatment with BJIKT and anti-PD-L1 therapy significantly suppressed tumor growth in MC38-bearing mice and increased the proportion of cytotoxic T lymphocytes and natural killer cells in tumor tissues. Furthermore, BJIKT suppressed the population of myeloid-derived suppressor cells, suggesting that this combination treatment effectively regulates the immunological function of T-cells by improving the tumor microenvironment. The herbal formula BJIKT can be a novel therapeutic option for improving anti-PD-L1-based immunotherapy in patients with CRC.

Functional Mechanism of Ginsenoside Compound K on Tumor Growth and Metastasis

Ginsenosides, as the most important constituents of ginseng, have been extensively investigated in cancer chemoprevention and therapeutics. Among the ginsenosides, Compound K (CK), a rare protopanaxadiol type of ginsenoside, has been most broadly used for cancer treatment due to its high anticancer bioactivity. However, the functional mechanism of CK in cancer is not well known. This review describes the structure, transformation and pharmacological activity of CK and discusses the functional mechanisms of CK and its metabolites, which regulate signaling pathways related to tumor growth and metastasis. CK inhibits tumor growth by inducing tumor apoptosis and tumor cell differentiation, regulates the tumor microenvironment by suppressing tumor angiogenesis-related proteins, and downregulates the roles of immunosuppressive cells, such as myeloid-derived suppressor cells (MDSCs). There is currently much research on the potential development of CK as a new strategy when administered alone or in combination with other compounds.

Prognostic value and predictive biomarkers of phenotypes of tumor-associated macrophages in colorectal cancer

BACKGROUND

The roles of different subtypes of tumor-associated macrophages (TAMs) in predicting the prognosis of colorectal cancer (CRC) remain controversial. In this study, different subtypes of TAMs were investigated as prognostic and predictive biomarkers for CRC.

METHODS

Expressions of CD68, CD86 and CD163 were investigated by immunohistochemistry (IHC) and immunofluorescence (IF), and the correlation between the expression of CD86 and CD163 was calculated in colorectal cancer tissues from 64 CRC patients.

RESULTS

The results showed that high expressions of CD86⁺ and CD68⁺ CD86⁺ TAMs as well as low expression of CD163⁺ and CD68⁺ CD163⁺ TAMs were significantly associated with favorable overall survival (OS). The level of CD86 protein expression showed a negative correlation with CD163 protein expression. In addition, CD86 protein expression remarkably negative correlated with tumor differentiation and tumor node metastasis (TNM) stage, while CD163 protein expression significantly positive correlated with tumor differentiation and tumor size. As an independent risk factor, high expression of CD86 TAMs had prominently favorable prognostic efficacy while high expression of CD68⁺ CD163⁺ TAMs had significantly poor prognostic efficacy.

CONCLUSIONS

These results indicate that CD86⁺ and CD68⁺ CD163⁺ TAMs as prognostic and predictive biomarkers for CRC.

Kampo Formulae for the Treatment of Neuropathic Pain ∼ Especially the Mechanism of Action of Yokukansan ∼

Kampo medicine has been practiced as traditional medicine (TM) in Japan. Kampo medicine uses Kampo formulae that are composed of multiple crude drugs to make Kampo formulae. In Japan, Kampo formulae are commonly used instead of or combined with Western medicines. If drug therapy that follows the guidelines for neuropathic pain does not work or cannot be taken due to side effects, various Kampo formulae are considered as the next line of treatment. Since Kampo formulae are composed of two or more kinds of natural crude drugs, and their extracts contain many ingredients with pharmacological effects, one Kampo formula usually has multiple effects. Therefore, when selecting a formula, we consider symptoms other than pain. This review outlines the Kampo formulae that are frequently used for pain treatment and their crude drugs and the basic usage of each component. In recent years, Yokukansan (YKS) has become one of the most used Kampo formulae for pain treatment with an increasing body of baseline research available. We outline the known and possible mechanisms by which YKS exerts its pharmacologic benefits as an example of Kampo formulae's potency and holistic healing properties.

Impact of TCM on Tumor-Infiltrating Myeloid Precursors in the Tumor Microenvironment

The tumor microenvironment (TME) is composed of tumor cells, blood/lymphatic vessels, the tumor stroma, and tumor-infiltrating myeloid precursors (TIMPs) as a sophisticated pathological system to provide the survival environment for tumor cells and facilitate tumor metastasis. In TME, TIMPs, mainly including tumor-associated macrophage (TAM), tumor-associated dendritic cells (DCs), and myeloid-derived suppressor cells (MDSCs), play important roles in repressing the antitumor activity of T cell or other immune cells. Therefore, targeting those cells would be one novel efficient method to retard cancer progression. Numerous studies have shown that traditional Chinese medicine (TCM) has made extensive research in tumor immunotherapy. In the review, we demonstrate that Chinese herbal medicine (CHM) and its components induce tumor cell apoptosis, directly inhibiting tumor growth and invasion. Further, we discuss that TCM regulates TME to promote effective antitumor immune response, downregulates the numbers and function of TAMs/MDSCs, and enhances the antigen presentation ability of mature DCs. We also review the therapeutic effects of TCM herbs and their ingredients on TIMPs in TME and systemically analyze the regulatory mechanisms of TCM on those cells to have a deeper understanding of TCM in tumor immunotherapy. Those investigations on TCM may provide novel ideas for cancer treatment.

Immunotherapy Targeting Myeloid-Derived Suppressor Cells (MDSCs) in Tumor Microenvironment

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells that accumulate in tumor-bearing hosts to reduce T cells activity and promote tumor immune escape in the tumor microenvironment (TME). The immune system in the TME can be stimulated to elicit an anti-tumor immune response through immunotherapy. The main theory of immunotherapy resides on the plasticity of the immune system and its capacity to be re-educated into a potent anti-tumor response. Thus, MDSCs within the TME became one of the major targets to improve the efficacy of tumor immunotherapy, and therapeutic strategies for tumor MDSCs were developed in the last few years. In the article, we analyzed the function of tumor MDSCs and the regulatory mechanisms of agents targeting MDSCs in tumor immunotherapy, and reviewed their therapeutic effects in MDSCs within the TME. Those data focused on discussing how to promote the differentiation and maturation of MDSCs, reduce the accumulation and expansion of MDSCs, and inhibit the function, migration and recruitment of MDSCs, further preventing the growth, invasion and metastasis of tumor. Those investigations may provide new directions for cancer therapy.

ROS-Mediated Therapeutic Strategy in Chemo-/Radiotherapy of Head and Neck Cancer

Head and neck cancer is a highly genetic and metabolic heterogeneous collection of malignancies of the lip, oral cavity, salivary glands, pharynx, esophagus, paranasal sinuses, and larynx with five-year survival rates ranging from 12% to 93%. Patients with head and neck cancer typically present with advanced stage III, IVa, or IVb disease and are treated with comprehensive modality including chemotherapy, radiotherapy, and surgery. Despite advancements in treatment modality and technique, noisome recurrence, invasiveness, and resistance as well as posttreatment complications severely influence survival rate and quality of life. Thus, new therapeutic strategies are urgently needed that offer enhanced efficacy with less toxicity. ROS in cancer cells plays a vital role in regulating cell death, DNA repair, stemness maintenance, metabolic reprogramming, and tumor microenvironment, all of which have been implicated in resistance to chemo-/radiotherapy of head and neck cancer. Adjusting ROS generation and elimination to reverse the resistance of cancer cells without impairing normal cells show great hope in improving the therapeutic efficacy of chemo-/radiotherapy of head and neck cancer. In the current review, we discuss the pivotal and targetable redox-regulating system including superoxide dismutases (SODs), tripeptide glutathione (GSH), thioredoxin (Trxs), peroxiredoxins (PRXs), nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/keap1), and mitochondria electron transporter chain (ETC) complexes and their roles in regulating ROS levels and their clinical significance implicated in chemo-/radiotherapy of head and neck cancer. We also summarize several old drugs (referred to as the non-anti-cancer drugs used in other diseases for a long time) and small molecular compounds as well as natural herbs which effectively modulate cellular ROS of head and neck cancer to synergize the efficacy of conventional chemo-/radiotherapy. Emerging interdisciplinary techniques including photodynamic, nanoparticle system, and Bio-Electro-Magnetic-Energy-Regulation (BEMER) therapy are promising measures to broaden the potency of ROS modulation for the benefit of chemo-/radiotherapy in head and neck cancer.

Anticancer activities of phytoconstituents and their liposomal targeting strategies against tumor cells and the microenvironment

Various bioactive ingredients have been extracted from Chinese herbal medicines (CHMs) that affect tumor progression and metastasis. To further understand the mechanisms of CHMs in cancer therapy, this article summarizes the effects of five categories of CHMs and their active ingredients on tumor cells and the tumor microenvironment. Despite their treatment potential, the undesirable physicochemical properties (poor permeability, instability, high hydrophilicity or hydrophobicity, toxicity) and unwanted pharmacokinetic profiles (short half-life in blood and low bioavailability) restrict clinical studies of CHMs. Therefore, development of liposomes through relevant surface modifying techniques to achieve targeted CHM delivery for cancer cells, i.e., extracellular and intracellular targets and targets in tumor microenvironment or vasculature, have been reviewed. Current challenges of liposomal targeting of these phytoconstituents and future perspective of CHM applications are discussed to provide an informative reference for interested readers.