EGCG Inhibits Tumor Growth in Melanoma by Targeting JAK-STAT Signaling and Its Downstream PD-L1/PD-L2-PD1 Axis in Tumors and Enhancing Cytotoxic T-Cell Responses

Targeting anticancer immunity in melanoma tumour microenvironment: unleashing the potential of adjuvants, drugs, and phytochemicals

Melanoma poses a challenge in oncology because of its aggressive nature and limited treatment modalities. The tumour microenvironment (TME) in melanoma contains unique properties such as an immunosuppressive and high-density environment, unusual vasculature, and a high number of stromal and immunosuppressive cells. In recent years, numerous experiments have focused on boosting the immune system to effectively remove malignant cells. Adjuvants, consisting of phytochemicals, toll-like receptor (TLR) agonists, and cytokines, have shown encouraging results in triggering antitumor immunity and augmenting the therapeutic effectiveness of anticancer therapy. These adjuvants can stimulate the maturation of dendritic cells (DCs) and infiltration of cytotoxic CD8+ T lymphocytes (CTLs). Furthermore, nanocarriers can help to deliver immunomodulators and antigens directly to the tumour stroma, thereby improving their efficacy against malignant cells. The remodelling of melanoma TME utilising phytochemicals, agonists, and other adjuvants can be combined with current modalities for improving therapy outcomes. This review article explores the potential of adjuvants, drugs, and their nanoformulations in enhancing the anticancer potency of macrophages, CTLs, and natural killer (NK) cells. Additionally, the capacity of these agents to repress the function of immunosuppressive components of melanoma TME, such as immunosuppressive subsets of macrophages, stromal and myeloid cells will be discussed.

Overcoming T Cell Exhaustion in Tumor Microenvironment via Immune Checkpoint Modulation with Nano-Delivery Systems for Enhanced Immunotherapy

Immune checkpoint blockade (ICB) therapy for tumors has arisen in growing interest. However, the low response rate of tumors to ICB is mainly attributed to the inhibitory infiltration of immune cells in the tumor microenvironment (TME). Despite the promising benefits of ICB, the therapeutic effects of antibodies are dependent on a high dose and long-term usage in the clinic, thereby leading to immune-related adverse effects. Accordingly, ICB combined with nano-delivery systems could be used to overcome T cell exhaustion, which reduces the side effects and the usage of antibodies with higher response rates in patients. In this review, the authors aim to overcome T cell exhaustion in TME via immune checkpoint modulation with nano-delivery systems for enhanced immunotherapy. Several strategies are summarized to combine ICB and nano-delivery systems to further enhance immunotherapy: a) expressing immune checkpoint on the surface of nano-delivery systems; b) loading immune checkpoint inhibitors into nano-delivery systems; c) loading gene-editing technology into nano-delivery systems; and d) nano-delivery systems mediated immune checkpoint modulation. Taken together, ICB combined with nano-delivery systems might be a promising strategy to overcome T cell exhaustion in TME for enhanced immunotherapy.

Harnessing the capacity of phytochemicals to enhance immune checkpoint inhibitor therapy of cancers: A focus on brain malignancies

Brain cancers, particularly glioblastoma multiforme (GBM), are challenging health issues with frequent unmet aspects. Today, discovering safe and effective therapeutic modalities for brain tumors is among the top research interests. Immunotherapy is an emerging area of investigation in cancer treatment. Since immune checkpoints play fundamental roles in repressing anti-cancer immunity, diverse immune checkpoint inhibitors (ICIs) have been developed, and some monoclonal antibodies have been approved clinically for particular cancers; nevertheless, there are significant concerns regarding their efficacy and safety in brain tumors. Among the various tools to modify the immune checkpoints, phytochemicals show good effectiveness and excellent safety, making them suitable candidates for developing better ICIs. Phytochemicals regulate multiple immunological checkpoint-related signaling pathways in cancer biology; however, their efficacy for clinical cancer immunotherapy remains to be established. Here, we discussed the involvement of immune checkpoints in cancer pathology and summarized recent advancements in applying phytochemicals in modulating immune checkpoints in brain tumors to highlight the state-of-the-art and give constructive prospects for future research.

Akkermansia muciniphila outer membrane protein regulates recruitment of CD8+ T cells in lung adenocarcinoma and through JAK-STAT signalling pathway

As a Gram-negative anaerobic bacterium, Akkermansia muciniphila (AKK) participates in the immune response in many cancers. Our study focused on the factors and molecular mechanisms of AKK affecting immune escape in lung adenocarcinoma (LUAD). We cultured AKK bacteria, prepared AKK outer membrane protein Amuc_1100 and constructed a subcutaneous graft tumour mouse model. A549, NCI-H1395 cells and mice were respectively treated with inactivated AKK, Amuc_1100, Ruxolitinib (JAK inhibitor) and RO8191 (JAK activator). CD8+ T cells that penetrated the membrane were counted in the Transwell assay. The toxicity of CD8+ T cells was evaluated by lactate dehydrogenase assay. Western blot was applied to determine JAK/STAT-related protein and PD-L1 expression, whilst CCL5, granzyme B and INF-γ expression were assessed through enzyme-linked immunosorbent assay (ELISA). The proportion of tumour-infiltrating CD8+ T cells and the levels of granzyme B and INF-γ were determined by flow cytometry. AKK markedly accelerated A549 and NCI-H1395 recruiting CD8+ T cells and enhanced CD8+ T cell toxicity. Amuc_1100 purified from AKK exerted the same promoting effects. Besides, Amuc_1100 dramatically suppressed PD-L1, p-STAT and p-JAK expression and enhanced CCL5, granzyme B and INF-γ expression. Treatment with Ruxolitinib accelerated A549 and NCI-H1395 cells recruiting CD8+ T cells, enhanced CD8+ T cell toxicity, CCL5, granzyme B and INF-γ expression, and inhibited PD-L1 expression. In contrast, the RO8191 treatment slowed down the changes induced by Amuc_1100. Animal experiments showed that Amuc_1100 was found to increase the number of tumour-infiltrating CD8+ T cells, increase the levels of granzyme B and INF-γ and significantly inhibit the expression of PD-L1, p-STAT and p-JAK, which exerted an antitumour effect in vivo. In conclusion, through inhibiting the JAK/STAT signalling pathway, AKK outer membrane protein facilitated the recruitment of CD8+ T cells in LUAD and suppressed the immune escape of cells.

EGC enhances tumor antigen presentation and CD8+ T cell-mediated antitumor immunity via targeting oncoprotein SND1

The Staphylococcal nuclease and Tudor domain containing 1 (SND1) has been identified as an oncoprotein. Our previous study demonstrated that SND1 impedes the major histocompatibility complex class I (MHC-I) assembly by hijacking the nascent heavy chain of MHC-I to endoplasmic reticulum-associated degradation. Herein, we aimed to identify inhibitors to block SND1-MHC-I binding, to facilitate the MHC-I presentation and tumor immunotherapy. Our findings validated the importance of the K490-containing sites in SND1-MHC-I complex. Through structure-based virtual screening and docking analysis, (-)-Epigallocatechin (EGC) exhibited the highest docking score to prevent the binding of MHC-I to SND1 by altering the spatial conformation of SND1. Additionally, EGC treatment resulted in increased expression levels of membrane-presented MHC-I in tumor cells. The C57BL/6J murine orthotopic melanoma model validated that EGC increases infiltration and activity of CD8+ T cells in both the tumor and spleen. Furthermore, the combination of EGC with programmed death-1 (PD-1) antibody demonstrated a superior antitumor effect. In summary, we identified EGC as a novel inhibitor of SND1-MHC-I interaction, prompting MHC-I presentation to improve CD8+ T cell response within the tumor microenvironment. This discovery presents a promising immunotherapeutic candidate for tumors.

18β-glycyrrhetinic acid suppresses Lewis lung cancer growth through protecting immune cells from ferroptosis

PURPOSE

18β-glycyrrhetinic acid (GA), the main metabolite of glycyrrhizic acid extracted from the root of licorice, has been reported to possess anti-cancer and immunomodulatory activity, but the mechanisms are not well understood. Recent studies have shown that ferroptosis of immune cells is involved in tumor-associated immune suppression. The purpose of this study was to investigate whether the enhanced immune response via inhibiting immune cell ferroptosis contributed to the anticancer effect of 18β-GA.

METHODS

Lewis Lung carcinoma mouse model and Murine CD8 + T cell culture model were used to examine the changes of immune response and ferroptosis of immune cells.

RESULTS

We found that 18β-GA was effective against lung cancer accompanied by enhanced activation of tumor-infiltrating CD8+ T cells in Lewis Lung carcinoma mouse model. Furthermore, we demonstrated that the boosted immune response by GA was attributed to its ability to inhibit arachidonic acid (AA)-mediated CD8+ T ferroptosis via suppressing CD36 expression.

CONCLUSION

The findings of the present study unraveled a novel mechanism underlying the anti-cancer and immunomodulatory activity of 18β-GA and support that 18β-GA holds potential to be used as an immune enhancer for lung cancer prevention or treatment.

Modulation of long noncoding RNAs by polyphenols as a novel potential therapeutic approach in lung cancer: A comprehensive review

Lung cancer stands as a formidable global health challenge, necessitating innovative therapeutic strategies. Polyphenols, bioactive compounds synthesized by plants, have garnered attention for their diverse health benefits, particularly in combating various cancers, including lung cancer. The advent of whole-genome and transcriptome sequencing technologies has illuminated the pivotal roles of long noncoding RNAs (lncRNAs), operating at epigenetic, transcriptional, and posttranscriptional levels, in cancer progression. This review comprehensively explores the impact of polyphenols on both oncogenic and tumor-suppressive lncRNAs in lung cancer, elucidating on their intricate regulatory mechanisms. The comprehensive examination extends to the potential synergies when combining polyphenols with conventional treatments like chemotherapy, radiation, and immunotherapy. Recognizing the heterogeneity of lung cancer subtypes, the review emphasizes the need for the integration of nanotechnology for optimized polyphenol delivery and personalized therapeutic approaches. In conclusion, we collect the latest research, offering a holistic overview of the evolving landscape of polyphenol-mediated modulation of lncRNAs in lung cancer therapy. The integration of polyphenols and lncRNAs into multidimensional treatment strategies holds promise for enhancing therapeutic efficacy and navigating the challenges associated with lung cancer treatment.

EGCG suppresses PD-1 expression of T cells via inhibiting NF-κB phosphorylation and nuclear translocation

Epigallocatechin-3-gallate (EGCG) is an important tea polyphenol with anti-tumor potential. Our previous studies revealed that EGCG was a promising immune checkpoint inhibitor (ICI) as it could downregulate expression of programmed cell death 1 ligand 1 (PD-L1) in tumor cells, thereby resulting tumor killing effect. In particular, EGCG can effectively avoid the inflammatory storm caused by anti-tumor therapy, which is a healthy green capacity absent from many ICIs. However, the relationship between EGCG and programmed cell death 1 (PD-1) of T cells remains unclear. In this work, we explored the effect of EGCG on T cells and found that EGCG suppressed PD-1 via inhibiting NF-κB phosphorylation and nuclear translocation. Furtherly, the capability of EGCG was confirmed in tumor-bearing mice to inhibit PD-1 expression in T cells and enhance apoptosis in tumor cells. These results implied that EGCG could inhibit the expression of PD-1 in T cells, thereby promoting anti-tumor effects of T cells. EGCG will be a promising candidate in anti-tumor therapy.

Nano-formulated delivery of active ingredients from traditional Chinese herbal medicines for cancer immunotherapy

Cancer immunotherapy has garnered promise in tumor progression, invasion, and metastasis through establishing durable and memorable immunological activity. However, low response rates, adverse side effects, and high costs compromise the additional benefits for patients treated with current chemical and biological agents. Chinese herbal medicines (CHMs) are a potential treasure trove of natural medicines and are gaining momentum in cancer immunomodulation with multi-component, multi-target, and multi-pathway characteristics. The active ingredient extracted from CHMs benefit generalized patients through modulating immune response mechanisms. Additionally, the introduction of nanotechnology has greatly improved the pharmacological qualities of active ingredients through increasing the hydrophilicity, stability, permeability, and targeting characteristics, further enhancing anti-cancer immunity. In this review, we summarize the mechanism of active ingredients for cancer immunomodulation, highlight nano-formulated deliveries of active ingredients for cancer immunotherapy, and provide insights into the future applications in the emerging field of nano-formulated active ingredients of CHMs.

Preclinical development and clinical studies of targeted JAK/STAT combined Anti-PD-1/PD-L1 therapy

Programmed cell death protein 1 (PD-1) binds to its ligand to help tumours evade the immune system and promote tumour progression. Although anti-PD-1/PD-L1 therapies show powerful effects in some patients, most patients are unable to benefit from this treatment due to treatment resistance. Therefore, it is important to overcome tumour resistance to PD-1/PD-L1 blockade. There is substantial evidence suggesting that the JAK/STAT signalling pathway plays a significant role in PD-1/PD-L1 expression and anti-PD-1/PD-L1 treatment. Herein, we describe the effects of the JAK/STAT signalling pathway on PD-1/PD-L1. Subsequently, the relationship between molecular mutations in the JAK/STAT signalling pathway and immune resistance was analysed. Finally, the latest advancements in drugs targeting the JAK/STAT pathway combined with PD1/PD-L1 inhibitors are summarised.

Decoding the synergistic potential of MAZ-51 and zingerone as therapy for melanoma treatment in alignment with sustainable development goals

Melanoma, an invasive class of skin cancer, originates from mutations in melanocytes, the pigment-producing cells. Globally, approximately 132,000 new cases are reported each year, and in South Africa, the incidence stands at 2.7 per 100,000 people, signifying a worrisome surge in melanoma rates. Therefore, there is a need to explore treatment modalities that will target melanoma's signalling pathways. Melanoma metastasis is aided by ligand activity of transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor-C (VEGF-C) and C-X-C chemokine ligand 12 (CXCL12) which bind to their receptors and promote tumour cell survival, lymphangiogenesis and chemotaxis. (3-(4-dimethylaminonaphthelen-1-ylmethylene)-1,3-dihydroindol-2-one) MAZ-51 is an indolinone-based molecule that inhibits VEGF-C induced phosphorylation of vascular endothelial growth factor receptor 3 (VEGFR-3). Despite the successful use of conventional cancer therapies, patients endure adverse side effects and cancer drug resistance. Moreover, conventional therapies are toxic to the environment and caregivers. The use of medicinal plants and their phytochemical constituents in cancer treatment strategies has become more widespread because of the rise in drug resistance and the development of unfavourable side effects. Zingerone, a phytochemical derived from ginger exhibits various pharmacological properties positioning it as a promising candidate for cancer treatment. This review provides an overview of melanoma biology and the intracellular signalling pathways promoting cell survival, proliferation and adhesion. There is a need to align health and environmental objectives within sustainable development goals 3 (good health and well-being), 13 (climate action) and 15 (life on land) to promote early detection of skin cancer, enhance sun-safe practices, mitigation of environmental factors and advancing the preservation of biodiversity, including medicinal plants. Thus, this review discusses the impact of cytostatic cancer drugs on patients and the environment and examines the potential use of phytochemicals as adjuvant therapy.

The Promising Role of Polyphenols in Skin Disorders

The biochemical characteristics of polyphenols contribute to their numerous advantageous impacts on human health. The existing research suggests that plant phenolics, whether consumed orally or applied directly to the skin, can be beneficial in alleviating symptoms and avoiding the development of many skin disorders. Phenolic compounds, which are both harmless and naturally present, exhibit significant potential in terms of counteracting the effects of skin damage, aging, diseases, wounds, and burns. Moreover, polyphenols play a preventive role and possess the ability to delay the progression of several skin disorders, ranging from small and discomforting to severe and potentially life-threatening ones. This article provides a concise overview of recent research on the potential therapeutic application of polyphenols for skin conditions. It specifically highlights studies that have investigated clinical trials and the use of polyphenol-based nanoformulations for the treatment of different skin ailments.

Immune escape and metastasis mechanisms in melanoma: breaking down the dichotomy

Melanoma is one of the most lethal neoplasms of the skin. Despite the revolutionary introduction of immune checkpoint inhibitors, metastatic spread, and recurrence remain critical problems in resistant cases. Melanoma employs a multitude of mechanisms to subvert the immune system and successfully metastasize to distant organs. Concerningly, recent research also shows that tumor cells can disseminate early during melanoma progression and enter dormant states, eventually leading to metastases at a future time. Immune escape and metastasis have previously been viewed as separate phenomena; however, accumulating evidence is breaking down this dichotomy. Recent research into the progressive mechanisms of melanoma provides evidence that dedifferentiation similar to classical epithelial to mesenchymal transition (EMT), genes involved in neural crest stem cell maintenance, and hypoxia/acidosis, are important factors simultaneously involved in immune escape and metastasis. The likeness between EMT and early dissemination, and differences, also become apparent in these contexts. Detailed knowledge of the mechanisms behind "dual drivers" simultaneously promoting metastatically inclined and immunosuppressive environments can yield novel strategies effective in disabling multiple facets of melanoma progression. Furthermore, understanding progression through these drivers may provide insight towards novel treatments capable of preventing recurrence arising from dormant dissemination or improving immunotherapy outcomes.

Phytochemicals in regulating PD-1/PD-L1 and immune checkpoint blockade therapy

Clinical treatment and preclinical studies have highlighted the role of immune checkpoint blockade in cancer treatment. Research has been devoted to developing immune checkpoint inhibitors in combination with other drugs to achieve better efficacy or reduce adverse effects. Phytochemicals sourced from vegetables and fruits have demonstrated antiproliferative, proapoptotic, anti-migratory, and antiangiogenic effects against several cancers. Phytochemicals also modulate the tumor microenvironment such as T cells, regulatory T cells, and cytokines. Recently, several phytochemicals have been reported to modulate immune checkpoint proteins in in vivo or in vitro models. Phytochemicals decreased programmed cell death ligand-1 expression and synergized programmed cell death receptor 1 (PD-1) monoclonal antibody to suppress tumor growth. Combined administration of phytochemicals and PD-1 monoclonal antibody enhanced the tumor growth inhibition as well as CD4+ /CD8+ T-cell infiltration. In this review, we discuss immune checkpoint molecules as potential therapeutic targets of cancers. We further assess the impact of phytochemicals including carotenoids, polyphenols, saponins, and organosulfur compounds on cancer PD-1/programmed cell death ligand-1 immune checkpoint molecules and document their combination effects with immune checkpoint inhibitors on various malignancies.

The roles of epigallocatechin gallate in the tumor microenvironment, metabolic reprogramming, and immunotherapy

Cancer, a disease that modern medicine has not fully understood and conquered, with its high incidence and mortality, deprives countless patients of health and even life. According to global cancer statistics, there were an estimated 19.3 million new cancer cases and nearly 10 million cancer deaths in 2020, with the age-standardized incidence and mortality rates of 201.0 and 100.7 per 100,000, respectively. Although remarkable advancements have been made in therapeutic strategies recently, the overall prognosis of cancer patients remains not optimistic. Consequently, there are still many severe challenges to be faced and difficult problems to be solved in cancer therapy today. Epigallocatechin gallate (EGCG), a natural polyphenol extracted from tea leaves, has received much attention for its antitumor effects. Accumulating investigations have confirmed that EGCG can inhibit tumorigenesis and progression by triggering apoptosis, suppressing proliferation, invasion, and migration, altering tumor epigenetic modification, and overcoming chemotherapy resistance. Nevertheless, its regulatory roles and biomolecular mechanisms in the immune microenvironment, metabolic microenvironment, and immunotherapy remain obscure. In this article, we summarized the most recent updates about the effects of EGCG on tumor microenvironment (TME), metabolic reprogramming, and anti-cancer immunotherapy. The results demonstrated EGCG can promote the anti-cancer immune response of cytotoxic lymphocytes and dendritic cells (DCs), attenuate the immunosuppression of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), and inhibit the tumor-promoting functions of tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), and various stromal cells including cancer-associated fibroblasts (CAFs), endothelial cells (ECs), stellate cells, and mesenchymal stem/stromal cells (MSCs). Additionally, EGCG can suppress multiple metabolic reprogramming pathways, including glucose uptake, aerobic glycolysis, glutamine metabolism, fatty acid anabolism, and nucleotide synthesis. Finally, EGCG, as an immunomodulator and immune checkpoint blockade, can enhance immunotherapeutic efficacy and may be a promising candidate for antitumor immunotherapy. In conclusion, EGCG plays versatile regulatory roles in TME and metabolic reprogramming, which provides novel insights and combined therapeutic strategies for cancer immunotherapy.

The current landscape of the antimicrobial peptide melittin and its therapeutic potential

Melittin, a main component of bee venom, is a cationic amphiphilic peptide with a linear α-helix structure. It has been reported that melittin can exert pharmacological effects, such as antitumor, antiviral and anti-inflammatory effects in vitro and in vivo. In particular, melittin may be beneficial for the treatment of diseases for which no specific clinical therapeutic agents exist. Melittin can effectively enhance the therapeutic properties of some first-line drugs. Elucidating the mechanism underlying melittin-mediated biological function can provide valuable insights for the application of melittin in disease intervention. However, in melittin, the positively charged amino acids enables it to directly punching holes in cell membranes. The hemolysis in red cells and the cytotoxicity triggered by melittin limit its applications. Melittin-based nanomodification, immuno-conjugation, structural regulation and gene technology strategies have been demonstrated to enhance the specificity, reduce the cytotoxicity and limit the off-target cytolysis of melittin, which suggests the potential of melittin to be used clinically. This article summarizes research progress on antiviral, antitumor and anti-inflammatory properties of melittin, and discusses the strategies of melittin-modification for its future potential clinical applications in preventing drug resistance, enhancing the selectivity to target cells and alleviating cytotoxic effects to normal cells.

Modulatory Role of Phytochemicals/Natural Products in Cancer Immunotherapy

Immunotherapy is a newly emerging and effective approach to treating cancer. However, there are many challenges associated with using checkpoint inhibitors in this treatment strategy. The component of the tumor microenvironment plays a crucial role in antitumor immune response, regulating tumor immune surveillance and immunological evasion. Natural products/phytochemicals can modulate the tumor microenvironment and function as immunomodulatory agents. In clinical settings, there is a strong need to develop synergistic combination regimens using natural products that can effectively enhance the therapeutic benefits of immune checkpoint inhibitors relative to their effectiveness as single therapies. The review discusses immunotherapy, its side effects, and a summary of evidence suggesting the use of natural products to modulate immune checkpoint pathways.

Bitter Phytochemicals as Novel Candidates for Skin Disease Treatment

Skin diseases represent a global healthcare challenge due to their rising incidence and substantial socio-economic burden. While biological, immunological, and targeted therapies have brought a revolution in improving quality of life and survival rates for certain dermatological conditions, there remains a stringent demand for new remedies. Nature has long served as an inspiration for drug development. Recent studies have identified bitter taste receptors (TAS2Rs) in both skin cell lines and human skin. Additionally, bitter natural compounds have shown promising benefits in addressing skin aging, wound healing, inflammatory skin conditions, and even skin cancer. Thus, TAS2Rs may represent a promising target in all these processes. In this review, we summarize evidence supporting the presence of TAS2Rs in the skin and emphasize their potential as drug targets for addressing skin aging, wound healing, inflammatory skin conditions, and skin carcinogenesis. To our knowledge, this is a pioneering work in connecting information on TAS2Rs expression in skin and skin cells with the impact of bitter phytochemicals on various beneficial effects related to skin disorders.

Phytochemical-Based Nanomedicine for Targeting Tumor Microenvironment and Inhibiting Cancer Chemoresistance: Recent Advances and Pharmacological Insights

Cancer remains the leading cause of death and rapidly evolving disease worldwide. The understanding of disease pathophysiology has improved through advanced research investigation, and several therapeutic strategies are being used for better cancer treatment. However, the increase in cancer relapse and metastatic-related deaths indicate that available therapies and clinically approved chemotherapy drugs are not sufficient to combat cancer. Further, the constant crosstalk between tumor cells and the tumor microenvironment (TME) is crucial for the development, progression, metastasis, and therapeutic response to tumors. In this regard, phytochemicals with multimodal targeting abilities can be used as an alternative to current cancer therapy by inhibiting cancer survival pathways or modulating TME. However, due to their poor pharmacokinetics and low bioavailability, the success of phytochemicals in clinical trials is limited. Therefore, developing phytochemical-based nanomedicine or phytonanomedicine can improve the pharmacokinetic profile of these phytochemicals. Herein, the molecular characteristics and pharmacological insights of the proposed phytonanomedicine in cancer therapy targeting tumor tissue and altering the characteristics of cancer stem cells, chemoresistance, TME, and cancer immunity are well discussed. Further, we have highlighted the clinical perspective and challenges of phytonanomedicine in filling the gap in potential cancer therapeutics using various nanoplatforms. Overall, we have discussed how clinical success and pharmacological insights could make it more beneficial to boost the concept of nanomedicine in the academic and pharmaceutical fields to counter cancer metastases and drug resistance.

Green tea extract improves cyclophosphamide-induced immunosuppression in mouse spleen and enhances the immune activity of RAW 264.7 cells

Cyclophosphamide (CP) is mainly used to treat autoimmune diseases and cancer; however, it damages normal immune cells. Therefore, the effects of chemotherapy on CP are limited. Notably, green tea has been reported to effectively modulate immune function. Here, given the pharmacological properties of green tea, we evaluated the ability of green tea extract (GTE) to restore immunity suppressed by CP in vivo and to activate macrophages in vitro. GTE significantly improved the suppressed immune function, including spleen index and proliferation of spleen T lymphocytes, as revealed by histopathological examination and flow cytometry analysis. Moreover, GTE effectively activated RAW 264.7, as represented by the induction of nitric oxide, reactive oxygen species, and cytokine levels. GTE also increased the phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B in RAW 264.7 cells. In conclusion, GTE ameliorated CP-induced immunosuppression in mice and stimulated immune activity in RAW 264.7 cells, possibly by activating the MAPK signaling pathway. These findings suggest that GTE has the potential to be used as a supplementary agent in chemotherapy for CP.

Recent Strategies for Cancer Therapy: Polymer Nanoparticles Carrying Medicinally Important Phytochemicals and Their Cellular Targets

Cancer is a leading cause of death in the world today. In addition to the side effects of the chemotherapeutic drugs used to treat cancer, the development of resistance to the drugs renders the existing drugs ineffective. Therefore, there is an urgent need to develop novel anticancer agents. Medicinally important phytochemicals such as curcumin, naringenin, quercetin, epigallocatechin gallate, thymoquinone, kaempferol, resveratrol, genistein, and apigenin have some drawbacks, including low solubility in water, stability and bioavailability issues, despite having significant anticancer effects. Encapsulation of these natural compounds into polymer nanoparticles (NPs) is a novel technology that could overcome these constraints. In comparison to the free compounds, phytochemicals loaded into nanoparticles have greater activity and bioavailability against many cancer types. In this review, we describe the preparation and characterization of natural phytochemical-loaded polymer NP formulations with significant antioxidant and anti-inflammatory effects, their in vitro and in vivo anticancer activities, as well as their possible cellular targets.

Cancer cell-derived extracellular vesicles drive pre-metastatic niche formation of lymph node via IFNGR1/JAK1/STAT1-activated-PD-L1 expression on FRCs in head and neck cancer

OBJECTIVE

The aim of this study is to evaluate the role of FRCs regulated by cancer cell-derived extracellular vesicles (CEVs) played in pre-metastatic niche (PMN) formation of lymph node (LN).

MATERIALS AND METHODS

The FRCs in sixty fresh cervical LNs from 20 patients were evaluated by flow cytometric analysis. Cells in LN with or without metastasis were analyzed by single-cell RNA sequencing (scRNA-seq). CEVs were isolated from the culture supernatant of primarily cultured cancer cells and cocultured with FRCs. Mass Spectrometry was used to identify LN metastasis related protein in CEVs. The activation of IFNGR1/JAK1/STAT1-activated-PD-L1 pathway in FRCs was detected by western blotting. FRCs were co-cultured with CD8+ T lymphocytes to confirm the cytotoxicity assay of FRCs.

RESULTS

The proportion of fibroblastic reticular cells (FRCs) was significantly higher in micro-metastatic LN in head and neck squamous cell carcinoma patients (HNSCC, p < 0.05) and scRNA-seq analysis further showed a high focus of extracellular vesicles-related pathway on FRCs in LN with metastasis (p < 0.05). Interferon gamma receptor 1 (IFNGR1) in CEVs can be engulfed by FRCs and promote PD-L1 expression on FRCs via JAK1-STAT1 pathway, resulting in an increased CD8+ T cell exhaustion.

CONCLUSION

IFNGR1, originated from cancer cell-derived extracellular vesicles, promote PD-L1 expression on FRCs and subsequent CD8+ T cell exhaustion via JAK1-STAT1 activation, which facilitate pre-metastatic niche formation and tumor metastasis in sentinel lymph node in HNSCC.

Maltol has anti-cancer effects via modulating PD-L1 signaling pathway in B16F10 cells

Introduction: Among skin cancers, melanoma has a high mortality rate. Recent advances in immunotherapy, particularly through immune checkpoint modulation, have improved the clinical treatment of melanoma. Maltol has various bioactivities, including anti-oxidant and anti-inflammatory properties, but the anti-melanoma property of maltol remains underexplored. The aim of this work is to explore the anti-melanoma potential of maltol through regulating immune checkpoints. Methods: The immune checkpoint PD-L1 was analyzed using qPCR, immunoblots, and immunofluorescence. Melanoma sensitivity towards T cells was investigated via cytotoxicity, cell viability, and IL-2 assays employing CTLL-2 cells. Results: Maltol was found to reduce melanin contents, tyrosinase activity, and expression levels of tyrosinase and tyrosinase-related protein 1. Additionally, maltol suppressed the proliferative capacity of B16F10 and induced cell cycle arrest. Maltol increased apoptotic rates by elevating cleaved caspase-3 and PARP. The co-treatment with maltol and cisplatin revealed a synergistic effect on inhibiting growth and promoting apoptosis. Maltol suppressed IFN-γ-induced PD-L1 and cisplatin-upregulated PD-L1 by attenuating STAT1 phosphorylation, thereby enhancing cisplatin's cytotoxicity against B16F10. Maltol augmented sensitivity to CTLL-2 cell-regulated melanoma destruction, leading to an increase in IL-2 production. Discussion: These findings demonstrate that maltol restricts melanoma growth through the downregulation of PD-L1 and elicits T cell-mediated anti-cancer responses, overcoming PD-L1-mediated immunotherapy resistance of cisplatin. Therefore, maltol can be considered as an effective therapeutic agent against melanoma.

Spice-Derived Phenolic Compounds: Potential for Skin Cancer Prevention and Therapy

Skin cancer is a condition characterized by the abnormal growth of skin cells, primarily caused by exposure to ultraviolet (UV) radiation from the sun or artificial sources like tanning beds. Different types of skin cancer include melanoma, basal cell carcinoma, and squamous cell carcinoma. Despite the advancements in targeted therapies, there is still a need for a safer, highly efficient approach to preventing and treating cutaneous malignancies. Spices have a rich history dating back thousands of years and are renowned for their ability to enhance the flavor, taste, and color of food. Derived from various plant parts like seeds, fruits, bark, roots, or flowers, spices are important culinary ingredients. However, their value extends beyond the culinary realm. Some spices contain bioactive compounds, including phenolic compounds, which are known for their significant biological effects. These compounds have attracted attention in scientific research due to their potential health benefits, including their possible role in disease prevention and treatment, such as cancer. This review focuses on examining the potential of spice-derived phenolic compounds as preventive or therapeutic agents for managing skin cancers. By compiling and analyzing the available knowledge, this review aims to provide insights that can guide future research in identifying new anticancer phytochemicals and uncovering additional mechanisms for combating skin cancer.

Epigallocatechin-3-Gallate Therapeutic Potential in Cancer: Mechanism of Action and Clinical Implications

Cellular signaling pathways involved in the maintenance of the equilibrium between cell proliferation and apoptosis have emerged as rational targets that can be exploited in the prevention and treatment of cancer. Epigallocatechin-3-gallate (EGCG) is the most abundant phenolic compound found in green tea. It has been shown to regulate multiple crucial cellular signaling pathways, including those mediated by EGFR, JAK-STAT, MAPKs, NF-κB, PI3K-AKT-mTOR, and others. Deregulation of the abovementioned pathways is involved in the pathophysiology of cancer. It has been demonstrated that EGCG may exert anti-proliferative, anti-inflammatory, and apoptosis-inducing effects or induce epigenetic changes. Furthermore, preclinical and clinical studies suggest that EGCG may be used in the treatment of numerous disorders, including cancer. This review aims to summarize the existing knowledge regarding the biological properties of EGCG, especially in the context of cancer treatment and prophylaxis.

MET Receptor Tyrosine Kinase Inhibition Reduces Interferon-Gamma (IFN-γ)-Stimulated PD-L1 Expression through the STAT3 Pathway in Melanoma Cells

Melanoma is the leading cause of death from cutaneous malignancy. While targeted therapy and immunotherapy with checkpoint inhibitors have significantly decreased the mortality rate of this disease, advanced melanoma remains a therapeutic challenge. Here, we confirmed that interferon-gamma (IFN-γ)-induced PD-L1 expression in melanoma cell lines. This increased expression was down-regulated by the reduction in phosphorylated STAT3 signaling via MET tyrosine kinase inhibitor treatment. Furthermore, immunoprecipitation and confocal immunofluorescence microscopy analysis reveals MET and PD-L1 protein-protein interaction and colocalization on the cell surface membrane of melanoma cells. Together, these findings demonstrate that the IFN-γ-induced PD-L1 expression in melanoma cells is negatively regulated by MET inhibition through the JAK/STAT3 signaling pathway and establish the colocalization and interaction between an RTK and a checkpoint protein in melanoma cells.

Co-delivery of EGCG and melittin with self-assembled fluoro-nanoparticles for enhanced cancer therapy

PURPOSE

Melittin (MPI) is a potential anticancer peptide due to its abilities of antitumor and immunomodulatory functions. Epigallocatechin-3-Ogallate (EGCG), a major extract of green tea, has shown great affinity for various types of biological molecules, especially for peptide/protein drugs. The aim of this study is to prepare a fluoro- nanoparticle (NP) formed by self-assembly of fluorinated EGCG (FEGCG) and MPI, and evaluate the effect of fluorine modification on MPI delivery and their synergistic antitumor effect.

METHODS

Characterization of FEGCG@MPI NPs was determined by dynamic light scattering (DLS) and transmission electron microscope (TEM). Biology functions of FEGCG@MPI NPs were detected by hemolysis effect, cytotoxicity, apoptosis, cellular uptake with confocal microscopy and flow cytometry. The protein expression levels of Bcl-2/Bax, IRF, STATT-1, P-STAT-1, and PD-L1 were determined via western blotting. A transwell assay and wound healing assay were used to detect the cell migration and invasion. The antitumor efficacy of FEGCG@MPI NPs was demonstrated in a subcutaneous tumor model.

RESULTS

Fluoro-nanoparticles could be formed by self-assembly of FEGCG and MPI, and fluorine modification on EGCG could ameliorate the side effect and delivery of MPI. The promoted therapeutics of FEGCG@MPI NPs could be achieved by regulating PD-L1 and apoptosis signaling, which might involve pathways of IRF, STAT-1/pSTAT-1, PD-L1, Bcl-2, and Bax in vitro. Moreover, FEGCG@MPI NPs could significantly inhibit the growth of tumor in vivo.

CONCLUSIONS

FEGCG@MPI NPs may offer a potential platform and promising strategy in cancer therapy.

The potential of epigallocatechin gallate in the chemoprevention and therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), one of the most notorious malignancies globally, has a high fatality and poor prognosis. Though remarkable breakthroughs have been made in the therapeutic strategies recently, the overall survival of HCC remains unsatisfactory. Consequently, the therapy of HCC remains a great challenge. Epigallocatechin gallate (EGCG), a natural polyphenol extracted from the leaves of the tea bush, has been extensively investigated for its antitumor effects. In this review, we summarize the previous literature to elucidate the roles of EGCG in the chemoprophylaxis and therapy of HCC. Accumulating evidence has confirmed EGCG prevents and inhibits the hepatic tumorigenesis and progression through multiple biological mechanisms, mainly involving hepatitis virus infection, oxidative stress, proliferation, invasion, migration, angiogenesis, apoptosis, autophagy, and tumor metabolism. Furthermore, EGCG enhances the efficacy and sensitivity of chemotherapy, radiotherapy, and targeted therapy in HCC. In conclusion, preclinical studies have confirmed the potential of EGCG for chemoprevention and therapy of HCC under multifarious experimental models and conditions. Nevertheless, there is an urgent need to explore the safety and efficacy of EGCG in the clinical practice of HCC.

Active ingredients of traditional Chinese medicine for enhancing the effect of tumor immunotherapy

Immunotherapy is a type of treatment that uses our own immune system to fight cancer. Studies have shown that traditional Chinese medicine (TCM) has antitumor activity and can enhance host immunity. This article briefly describes the immunomodulatory and escape mechanisms in tumors, as well as highlights and summarizes the antitumor immunomodulatory activities of some representative active ingredients of TCM. Finally, this article puts forward some opinions on the future research and clinical application of TCM, aiming to promote the clinical applications of TCM in tumor immunotherapy and to provide new ideas for the research of tumor immunotherapy using TCM.

In situ global proteomics profiling of EGCG targets using a cell-permeable and Click-able bioorthogonal probe

Despite possessing a wide spectrum of biological activities, molecular targets of EGCG remain elusive and as a result, its precise mode of action is still unknown. Herein, we have developed a novel cell-permeable and Click-able bioorthogonal probe for EGCG, YnEGCG for in situ detection and identification of its interacting proteins. The strategic structural modification on YnEGCG allowed it to retain innate biological activities of EGCG (IC₅₀ 59.52 ± 1.14 μM and 9.07 ± 0.01 μM for cell viability and radical scavenging activity, respectively). Chemoproteomics profiling identified 160 direct EGCG targets, with H:L ratio ≥ 1.10 from the list of 207 proteins, including multiple new proteins that were previously unknown. The targets were broadly distributed in various subcellular compartments suggesting a polypharmacological mode of action of EGCG. GO analysis revealed that the primary targets belonged to the enzymes that regulate key metabolic processes including glycolysis and energy homeostasis, also the cytoplasm (36 %) and mitochondria (15.6 %) contain the majority of EGCG targets. Further, we validated that EGCG interactome was closely associated with apoptosis indicating its role in inducing toxicity in cancer cells. For the first time, this in situ chemoproteomics approach could identify a direct and specific EGCG interactome under physiological conditions in an unbiased manner.

Melanoma Cellular Signaling Transduction Pathways Targeted by Polyphenols Action Mechanisms

Melanoma is the most aggressive type of skin cancer. Although different anti-melanoma treatments are available, their efficacy is still improvable, and the number of deaths continues to increase worldwide. A promising source of antitumor agents could be presented by polyphenols-natural plant-based compounds. Over the past decades, many studies have described multiple anticancer effects of polyphenols in melanoma, presenting their potential interactions with targeted molecules from different signaling pathways. However, to our knowledge, there is no comprehensive review on polyphenols-regulated mechanisms in melanoma cells available in the literature. To fulfill this gap, this article aims to summarize the current knowledge of molecular mechanisms of action regulated by polyphenols involved in melanoma initiation and progression. Here, we focus on in vitro and in vivo effects of polyphenol treatments on tumor-essential cellular pathways, such as cell proliferation, apoptosis, autophagy, inflammation, angiogenesis, and metastasis. Moreover, emerging studies regarding the well-marked role of polyphenols in the regulation of microRNAs (miRNAs), highlighting their contribution to melanoma development, are also epitomized. Finally, we hope this review will provide a firm basis for developing polyphenol-based therapeutic agents in melanoma treatment.

Phytochemicals as Immunomodulatory Agents in Melanoma

Cutaneous melanoma is an immunogenic highly heterogenic tumor characterized by poor outcomes when it is diagnosed late. Therefore, immunotherapy in combination with other anti-proliferative approaches is among the most effective weapons to control its growth and metastatic dissemination. Recently, a large amount of published reports indicate the interest of researchers and clinicians about plant secondary metabolites as potentially useful therapeutic tools due to their lower presence of side effects coupled with their high potency and efficacy. Published evidence was reported in most cases through in vitro studies but also, with a growing body of evidence, through in vivo investigations. Our aim was, therefore, to review the published studies focused on the most interesting phytochemicals whose immunomodulatory activities and/or mechanisms of actions were demonstrated and applied to melanoma models.

Dexamethasone and OLT1177 Cooperate in the Reduction of Melanoma Growth by Inhibiting STAT3 Functions

The NLRP3 inflammasome is a multimolecular complex that processes inactive IL-1β and IL-18 into proinflammatory cytokines. OLT1177 is an orally active small compound that specifically inhibits NLRP3. Here, B16F10 melanoma were implanted in mice and treated with OLT1177 as well as combined with the glucocorticoid dexamethasone. At sacrifice, OLT1177 treated mice had significantly smaller tumors compared to tumor-bearing mice treated with vehicle. However, the combined treatment of OLT1177 plus dexamethasone revealed a greater suppression of tumor growth. This reduction was accompanied by a downregulation of nuclear and mitochondrial STAT3-dependent gene transcription and by a significant reduction of STAT3 Y705 and S727 phosphorylations in the tumors. In vitro, the human melanoma cell line 1205Lu, stimulated with IL-1α, exhibited significantly lower levels of STAT3 Y705 phosphorylation by the combination treatment, thus affecting the nuclear functions of STAT3. In the same cells, STAT3 serine 727 phosphorylation was also lower, affecting the mitochondrial functions of STAT3. In addition, metabolic analyses revealed a marked reduction of ATP production rate and glycolytic reserve in cells treated with the combination of OLT1177 plus dexamethasone. These findings demonstrate that the combination of OLT1177 and dexamethasone reduces tumor growth by targeting nuclear as well as mitochondrial functions of STAT3.

Anticarcinogenic potentials of tea catechins

Catechins are a cluster of polyphenolic bioactive components in green tea. Anticarcinogenic effects of tea catechins have been reported since the 1980s, but it has been controversial. The present paper reviews the advances in studies on the anticarcinogenic activities of tea and catechins, including epidemiological evidence and anticarcinogenic mechanism. Tea catechins showed antagonistic effects on many cancers, such as gynecological cancers, digestive tract cancers, incident glioma, liver and gallbladder cancers, lung cancer, etc. The mechanism underlying the anticarcinogenic effects of catechins involves in inhibiting the proliferation and growth of cancer cells, scavenging free radicals, suppressing metastasis of cancer cells, improving immunity, interacting with other anticancer drugs, and regulating signaling pathways. The inconsistent results and their causes are also discussed in this paper.

Modern aspects of the use of natural polyphenols in tumor prevention and therapy

Polyphenols are secondary plant metabolites or organic compounds synthesized by them. In other words, these are molecules that are found in plants. Due to the wide variety of polyphenols and the plants in which they are found, these compounds are divided according to the source of origin, the function of the polyphenols, and their chemical structure; where the main ones are flavonoids. All the beneficial properties of polyphenols have not yet been studied, since this group of substances is very extensive and diverse. However, most polyphenols are known to be powerful antioxidants and have anti-inflammatory effects. Polyphenols help fight cell damage caused by free radicals and immune system components. In particular, polyphenols are credited with a preventive effect that helps protect the body from certain forms of cancer. The onset and progression of tumors may be related directly to oxidative stress, or inflammation. These processes can increase the amount of DNA damage and lead to loss of control over cell division. A number of studies have shown that oxidative stress uncontrolled by antioxidants or an uncontrolled and prolonged inflammatory process increases the risk of developing sarcoma, melanoma, and breast, lung, liver, and prostate cancer. Therefore, a more in-depth study of the effect of polyphenolic compounds on certain signaling pathways that determine the complex cascade of oncogenesis is a promising direction in the search for new methods for the prevention and treatment of tumors.

Understanding the functional inflammatory factors involved in therapeutic response to immune checkpoint inhibitors for pan-cancer

Immune checkpoint inhibitors (ICIs) fight tumor progression by activating immune conditions. The inflammatory factors are playing a functional role in programmed death-1 (PD-1) or other immune checkpoints. They are involved in regulating the expression of programmed death ligand-1 (PD-L1), the only predictor recognized by the guidelines in response to ICIs. In addition, abundant components of the tumor microenvironment (TME) all interact with various immune factors contributing to the response to ICIs, including infiltration of various immune cells, extracellular matrix, and fibroblasts. Notably, the occurrence of immune-related adverse events (irAEs) in patients receiving ICIs is increasingly observed in sundry organs. IrAEs are often regarded as an inflammatory factor-mediated positive feedback loop associated with better response to ICIs. It deserves attention because inflammatory factors were observed to be different when targeting different immune checkpoints or in the presence of different irAEs. In the present review, we address the research progresses on regulating inflammatory factors for an intentional controlling anti-cancer response with immune checkpoint inhibitors.

When Natural Compounds Meet Nanotechnology: Nature-Inspired Nanomedicines for Cancer Immunotherapy

Recent significant strides of natural compounds in immunomodulation have highlighted their great potential against cancer. Despite many attempts being made for cancer immunotherapy, the biomedical application of natural compounds encounters a bottleneck because of their unclear mechanisms, low solubility and bioavailability, and limited efficacy. Herein, we summarize the immune regulatory mechanisms of different natural compounds at each step of the cancer-immunity cycle and highlight their anti-tumor potential and current limitations. We then propose and present various drug delivery strategies based on nanotechnology, including traditional nanoparticles (NPs)-based delivery strategies (lipid-based NPs, micelles, and polysaccharide/peptide/protein-based NPs) and novel delivery strategies (cell-derived NPs and carrier-free NPs), thus providing solutions to break through existing bottlenecks. Furthermore, representative applications of nature-inspired nanomedicines are also emphasized in detail with the advantages and disadvantages discussed. Finally, the challenges and prospects of natural compounds for cancer immunotherapy are provided, hopefully, to facilitate their far-reaching development toward clinical translation.

Current insight into the regulation of PD-L1 in cancer

The molecular mechanisms underlying cancer immune escape are a core topic in cancer immunology research. Cancer cells can escape T cell-mediated cellular cytotoxicity by exploiting the inhibitory programmed cell-death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1, CD274) immune checkpoint. Studying the PD-L1 regulatory pattern of tumor cells will help elucidate the molecular mechanisms of tumor immune evasion and improve cancer treatment. Recent studies have found that tumor cells regulate PD-L1 at the transcriptional, post-transcriptional, and post-translational levels and influence the anti-tumor immune response by regulating PD-L1. In this review, we focus on the regulation of PD-L1 in cancer cells and summarize the underlying mechanisms.

Chemico-biological aspects of (-)-epigallocatechin-3-gallate (EGCG) to improve its stability, bioavailability and membrane permeability: Current status and future prospects

Natural products have been a bedrock for drug discovery for decades. (-)-Epigallocatechin-3-gallate (EGCG) is one of the widely studied natural polyphenolic compounds derived from green tea. It is the key component believed to be responsible for the medicinal value of green tea. Significant studies implemented in in vitro, in cellulo, and in vivo models have suggested its anti-oxidant, anti-cancer, anti-diabetic, anti-inflammatory, anti-microbial, neuroprotective activities etc. Despite having such a wide array of therapeutic potential and promising results in preclinical studies, its applicability to humans has encountered with rather limited success largely due to the poor bioavailability, poor membrane permeability, rapid metabolic clearance and lack of stability of EGCG. Therefore, novel techniques are warranted to address those limitations so that EGCG or its modified analogs can be used in the clinical setup. This review comprehensively covers different strategies such as structural modifications, nano-carriers as efficient drug delivery systems, synergistic studies with other bioactivities to improve the chemico-biological aspects (e.g., stability, bioavailability, permeability, etc.) of EGCG for its enhanced pharmacokinetics and pharmacological properties, eventually enhancing its therapeutic potentials. We think this review article will serve as a strong platform with comprehensive literature on the development of novel techniques to improve the bioavailability of EGCG so that it can be translated to the clinical applications.