The therapeutic potential of urolithin A for cancer treatment and prevention

Urolithins: Emerging natural compound targeting castration-resistant prostate cancer (CRPC)

Castration-resistant prostate cancer (CRPC) presents a significant challenge due to its resistance to conventional androgen deprivation therapies. Urolithins, bioactive metabolites derived from ellagitannins, have recently emerged as promising therapeutic agents for CRPC. Urolithins not only inhibit androgen receptor (AR) signaling, a crucial factor in the progression of CRPC, but also play a key role in regulating oxidative stress by their antioxidant properties, thereby inhibiting increased reactive oxygen species, a common feature of the aggressive nature of CRPC. Research has shown that urolithins induce apoptosis and diminish pro-survival signaling, leading to tumor inhibition. This review delves into the intricate mechanisms through which urolithins exert their therapeutic effects, focusing on both AR-dependent and AR-independent pathways. It also explores the exciting potential of combining urolithins with androgen ablation therapy, opening new avenues for CRPC treatment.

Urolithin as a Metabolite of Ellagitannins and Ellagic Acid from Fruits and Nuts Produced by the Gut Microbiota: Its Role on Non-Communicable Diseases

PURPOSE OF REVIEW

This narrative review investigates how urolithins produced by the gut microbiota can regulate transcription factors (such as NRF2, NF-kB, and PPAR-γ) associated with senescence, inflammation, and imbalanced redox status. It also discusses the potential benefits of urolithins for patients with chronic diseases, including cardiovascular disease, cancer, diabetes, obesity, and chronic kidney disease.

RECENT FINDINGS

Studies have shown that urolithins have many health benefits, including anti-inflammatory, antioxidant, antimicrobial, and anti-atherosclerotic effects. They are also linked to improved mitochondrial function and imbalanced redox associated with activating the Nrf2/ARE pathway. Urolithins are metabolites produced by gut microbiota from ellagic acid and ellagitannins, polyphenols primarily found in nuts and fruits, including pomegranates and berries like raspberries, cloudberries, and blackberries.

Ellagic Acid and Gut Microbiota: Interactions, and Implications for Health

Ellagic acid (EA), a widely distributed natural polyphenolic acid existing in many kinds of plant-based foods, undergoes complex physical and chemical transformations during digestion and biotransformation. Particularly, EA is metabolized by gut microbiota and transformed into urolithins in the colon. These metabolites exhibit enhanced bioavailability and bioactivity. This review explores the intricate interactions between EA and gut microbiota, emphasizing their implications for human health. We discuss the role of gut microbiota in EA metabolism, resulting in distinct metabolic phenotypes associated with varying urolithin production profiles. EA and its gut-derived metabolites, urolithins, have been reported to have the potential to modulate the microbial community composition and function of gut microbiota, promoting beneficial bacteria while reducing harmful ones. Furthermore, EA and urolithins exhibit a spectrum of beneficial biological activities, including antioxidant, anti-inflammatory, and anticancer properties, along with enhancements to intestinal barrier function and modulatory effects on metabolic and cardiovascular systems, through molecular mechanisms such as activating Nrf2 and inhibiting NF-κB pathways. The review highlights and compares the potential of EA and its gut microbial metabolites in the prevention and treatment of various diseases. However, further studies are required to elucidate the underlying mechanisms of the interactions between EA and gut microbiota and their health benefits. Continued investigation into EA and its metabolites is essential for advancing our understanding of their role in promoting human health and developing novel therapeutic applications.

Urolithin A increases the natural killer activity of PBMCs in patients with prostate cancer

Background

The natural killer (NK) activity of peripheral blood mononuclear cells (PBMCs) is a crucial defense against the onset and spread of cancer. Studies have shown that patients with reduced NK activity are more susceptible to cancer, and NK activity tends to decrease due to cancer-induced immune suppression. Enhancing the natural cytotoxicity of PBMCs remains a significant task in cancer research.

Methods

This study investigates the potential of urolithin A, a polyphenolic metabolite produced by the gut microbiota, to enhance the natural cytotoxicity of PBMCs in prostate cancer patients and healthy subjects. We investigated the possible role of aryl hydrocarbon receptor (AhR) in this capability of urolithin A. We analyzed the ability of PBMCs preincubated with urolithin A, AhR agonist or antagonist to kill K562 (human chronic myelogenous leukemia) target cells.

Results

Our results demonstrate that urolithin A enhances the natural cytotoxicity of PBMCs in a dose-dependent manner. Specifically, at a concentration of 10 μM, urolithin A increased the NK activity of PBMCs from prostate cancer patients by an average of 23% (95% CI, 7%-38%). In addition, urolithin A modulates the level of cytokine production by PBMCs, decreasing the level of fractalkine, IL-8, and MCP-3. An AhR antagonist (CH223191, 1 μM) also increased NK activity, while an AhR agonist (β-naphthoflavone, 10 μM) did not increase NK activity and partially inhibited the urolithin A-induced enhancement.

Conclusion

Urolithin A increases the NK activity of PBMCs from patients with prostate cancer and healthy subjects, and the AhR may be involved in this capability of urolithin A.

Tea polyphenols nanoparticles integrated with microneedles multifunctionally boost 5-aminolevulinic acid photodynamic therapy for skin cancer

5-aminolevulinic acid photodynamic therapy (ALA-PDT) is an emerging therapeutic strategy for skin cancer due to its noninvasiveness and high spatiotemporal selectivity. However, poor skin penetration, poor intratumoral delivery, the instability of aqueous ALA, and the tumor's inherent hypoxia microenvironment are major hurdles hindering the efficacy of ALA-PDT. Herein, we aim to address these challenges by using microneedles (MNs) to assist in delivering nanoparticles based on natural polymeric tea polyphenols (TP NPs) to self-assemble and load ALA (ALA@TP NPs). The TP NPs specifically increase cellular uptake of ALA by A375 and A431 cells and reduce mitochondrial membrane potential. Subsequently, the photosensitizer protoporphyrin IX derived from ALA accumulates in the tumor cells in a dose-dependent manner with TP NPs, generating reactive oxygen species to promote apoptosis and necrosis of A375 and A431 cells. Interestingly, TP NPs can ameliorate the tumor's inherent hypoxia microenvironment and rapid oxygen consumption during PDT by inhibiting hypoxia inducible factor-1α, thereby boosting reactive oxygen species (ROS) generation and enhancing ALA-PDT efficacy through a positive feedback loop. After ALA@TP NPs are loaded into MNs to fabricate ALA@TP NPs@MNs, the MNs enhance skin penetration and storage stability of ALA. Importantly, they exhibit remarkable antitumor efficacy in A375-induced melanoma and A431-induced squamous cell carcinoma with a reduced dose of ALA and reverse hypoxia in vivo. This study provides a facile and novel strategy that integrates MNs and green NPs of TP for addressing the bottlenecks of ALA-PDT and enhancing the ALA-PDT efficacy against skin cancers for future clinical translation.

The Lawson-loaded β-cyclodextrin nanocarriers (LB-NCs) a novel targeted cancer cell in stomach and breast cancer as a drug delivery system

Applying nanotechnology to design drug delivery systems is a promising turning point in cancer treatment strategies. In the current study, Lawson, a nonpolar anticancer phytochemical, was entrapped into β-cyclodextrin polymer to evaluate its selective cytotoxicity in several types of human cancer cell lines including MCF-7, AGS, A549, and PC3. The Lawson-loaded β-cyclodextrin nanocarriers (LB-NCs) were produced by applying a high-energy ultrasound-mediated homogenization technique. The LB-NCs were characterized by applying dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), zeta potential, and field emission scanning electron microscopy (FESEM) analysis. Also, the selective cytotoxic impact of the LB-NCs was studied by conducting the MTT assay on human MCF-7, AGS, A549, and PC3 cancer cell lines. Finally, the type of cellular death was evaluated by measuring the cell cycle status and apoptotic gene expression profile of the treated MCF-7 cells by conducting flow cytometry and Q-PCR methods, respectively. The synthesized negatively charged (- 23.8 mV) nanoparticles (348.12 nm) exhibited apoptotic activity in the human breast MCF-7 cancer cells by upregulating the apoptotic gene expression profile (Caspase 3, 8, and 9). The LB-NCs exhibited a significant selective cytotoxic effect on the human cancer cell lines compared with the normal HUVEC cells. However, variable toxic intensities were detected depending on the cancer cell type. Selective cancer cell-depended anticancer activity of the produced LB-NCs has the potential to be considered their safe efficient targeted anticancer activity. However, studying the animal cancer models has to be conducted to verify their selective toxicity and clarify the cellular death mechanism.

Urolithin A exerts anti-tumor effects on gastric cancer via activating autophagy-Hippo axis and modulating the gut microbiota

Gastric cancer (GC) treatment regimens are still unsatisfactory. Recently, Urolithin A (UroA) has gained tremendous momentum due to its anti-tumor properties. However, the therapeutic effect and underlying mechanisms of UroA in GC are unclear. We explored the effects and related mechanisms of UroA on GC both in vivo and in vitro. A Cell Counting Kit-8 was used to determine the influence of UroA on the proliferation of GC cell lines. The Autophagy inhibitor 3-methyladenine (3MA) was employed to clarify the role of autophagy in the anti-tumor effect of UroA. Simultaneously, we detected the core-component proteins involved in autophagy and its downstream pathways. Subsequently, the in vivo anti-tumor effect of UroA was determined using a xenograft mouse model. Western blotting was used to detect the core protein components of the anti-tumor pathways, and 16S rDNA sequencing was used to detect the effect of UroA on the gut microbiota. We found that UroA suppressed tumor progression. The use of 3MA undermined the majority of the inhibitory effect of UroA on tumor cell proliferation, further confirming the importance of autophagy in the anti-tumor effect of UroA. Invigorating of autophagy activated the downstream Hippo pathway, thereby inhibiting the Warburg effect and promoting cell apoptosis. In addition, UroA modulated the composition of the gut microbiota, as indicated by the increase of probiotics and the decrease of pathogenic bacteria. Our research revealed new anti-tumor mechanisms of UroA, which may be a promising candidate for GC treatment.

Pomegranate (Punica granatum L.) phytochemicals target the components of metabolic syndrome

Pomegranate (Punica granatum L.) is a multipurpose dietary and medicinal plant known for its ability to promote various health benefits. Metabolic syndrome (MetS) is a complex metabolic disorder driving health and socioeconomic challenges worldwide. It may be characterized by insulin resistance, abdominal obesity, hypertension, and dyslipidemia. This study aims to conduct a review of pomegranate's effects on MetS parameters using a mechanistic approach relying on pre-clinical studies. The peel, juice, roots, bark, seeds, flowers, and leaves of the fruit present several bioactive compounds that are related mainly to anti-inflammatory and antioxidant activities as well as cardioprotective, antidiabetic, and antiobesity effects. The use of the juice extract can work as a potent inhibitor of angiotensin-converting enzyme activities, consequently regulating blood pressure. The major bioactive compounds found within the fruit are phenolic compounds (hydrolysable tannins and flavonoids) and fatty acids. Alkaloids, punicalagin, ellagitannins, ellagic acid, anthocyanins, tannins, flavonoids, luteolin, and punicic acid are also present. The antihyperglycemia, antihyperlipidemia, and weight loss promoting effects are likely related to the anti-inflammatory and antioxidant effects. When considering clinical application, pomegranate extracts are found to be frequently well-tolerated, further supporting its efficacy as a treatment modality. We suggest that pomegranate fruit, extract, or processed products can be used to counteract MetS-related risk factors. This review represents an important step towards exploring potential avenues for further research in this area.

A dual-labeling molecule for efficient drug discovery of mitochondrial-lysosomal interactions

The close association between organelle interactions, such as mitochondrial-lysosomal interactions, and various diseases, including tumors, remains a challenge for drug discovering and identification. Conventional evaluation methods are often complex and multistep labeling procedures often generate false positives, such as cell damage. To overcome these limitations, we employed a single dual-color reporting molecule called Coupa, which labels mitochondria and lysosomes as blue and red, respectively. This facilitates the evaluation and discovering of drugs targeting mitochondria-lysosome contact (MLC). Using Coupa, we validated the effectiveness of various known antitumor drugs in intervening MLC by assessing their effect on key aspects, such as status, localization, and quantity. This provides evidence for the accuracy and applicability of our dual-color reporting molecule. Notably, we observed that several structural isomers of drugs, including Urolithin (A/B/C), exhibited distinct effects on MLC. In addition, Verteporfin and TEAD were found to induce anti-tumor effects by controlling MLC at the organelle level, suggesting a potential new mechanism of action. Collectively, Coupa offers a novel scientific tool for discovering drugs that target mitochondrial-lysosomal interactions. It not only distinguished the differential effects of structurally similar drugs on the same target, but also reveals new mechanisms underlying the reported antitumor properties of existing drugs. Ultimately, our findings contribute to the advancement of drug discovery and provide valuable insights into the complex interactions between organelles in a disease context.

Urolithin A Hijacks ERK1/2-ULK1 Cascade to Improve CD8+ T Cell Fitness for Antitumor Immunity

According to the latest evidence, the microbial metabolite Urolithin A (UA), known for its role in promoting cellular health, modulates CD8+ T cell-mediated antitumor activity. However, the direct target protein of UA and its underlying mechanism remains unclear. Here, this research identifies ERK1/2 as the specific target crucial for UA-mediated CD8+ T cell activation. Even at low doses, UA markedly enhances the persistence and effector functions of primary CD8+ cytotoxic T lymphocytes (CTLs) and human chimeric antigen receptor (CAR) T cells both in vitro and in vivo. Mechanistically, UA interacts directly with ERK1/2 kinases, enhancing their activation and subsequently facilitating T cell activation by engaging ULK1. The UA-ERK1/2-ULK1 axis promotes autophagic flux in CD8+ CTLs, enhancing cellular metabolism and maintaining reactive oxygen species (ROS) levels, as evidenced by increased oxygen consumption and extracellular acidification rates. UA-treated CD8+ CTLs also display elevated ATP levels and enhanced spare respiratory capacity. Overall, UA activates ERK1/2, inducing autophagy and metabolic adaptation, showcasing its potential in tumor immunotherapy and interventions for diseases involving ERKs.

Synthesis of urolithin derivatives and their anti-inflammatory activity

Two series of urolithin derivatives, totally 38 compounds, were synthesized. Their anti-inflammatory activity was investigated by detecting the inhibitory effects on the expression of TNF-α in bone marrow-derived macrophages (BMDMs), showing that 24 of 38 ones reduced the expression of TNF-α. Compound B2, the ring C opened derivative of urolithin B with a butoxycarbonyl substitution in ring A, showed the strongest inhibitory activity compared with that of indomethacin. Furthermore, B2 treatment decreased the expression of pro-inflammatory factors IL-1β, IL-6, iNOS and COX-2. Mechanically, the anti-inflammatory effect of B2 was related to the inhibition of NF-κB signaling pathway. These results clearly illustrated that B2 hold potential for application as an anti-inflammatory agent. The present study provided a viable approach to modify the gut metabolites for anti-inflammatory drug development.

Inhibitory Effects of Urolithins, Bioactive Gut Metabolites from Natural Polyphenols, against Glioblastoma Progression

We previously reported that proinflammatory cytokines, particularly tumor necrosis factor (TNF)-α, promoted tumor migration, invasion, and proliferation, thus worsening the prognosis of glioblastoma (GBM). Urolithins, the potent metabolites produced by the gut from pomegranate polyphenols, have anticancer properties. To develop an effective therapy for GBM, this study aimed to study the effects of urolithins against GBM. Urolithin A and B significantly reduced GBM migration, reduced epithelial-mesenchymal transition, and inhibited tumor growth. Moreover, urolithin A and B inhibited TNF-α-induced vascular cell adhesion molecule (VCAM)-1 and programmed death ligand 1 (PD-L1) expression, thereby reducing human monocyte (HM) binding to GBM cells. Aryl hydrocarbon receptor (AhR) level had higher expression in patients with glioma than in healthy individuals. Urolithins are considered pharmacological antagonists of AhR. We demonstrated that the inhibition of AhR reduced TNF-α-stimulated VCAM-1 and PD-L1 expression. Furthermore, human macrophage condition medium enhanced expression of PD-L1 in human GBM cells. Administration of the AhR antagonist attenuated the enhancement of PD-L1, indicating the AhR modulation in GBM progression. The modulatory effects of urolithins in GBM involve inhibiting the Akt and epidermal growth factor receptor pathways. The present study suggests that urolithins can inhibit GBM progression and provide valuable information for anti-GBM strategy.

Inhibition of Cancer Development by Natural Plant Polyphenols: Molecular Mechanisms

Malignant tumors remain one of the main sources of morbidity and mortality around the world. A chemotherapeutic approach to cancer treatment poses a multitude of challenges, primarily due to the low selectivity and genotoxicity of the majority of chemotherapeutic drugs currently used in the clinical practice, often leading to treatment-induced tumors formation. Highly selective antitumor drugs can largely resolve this issue, but their high selectivity leads to significant drawbacks due to the intrinsic tumor heterogeneity. In contrast, plant polyphenols can simultaneously affect many processes that are involved in the acquiring and maintaining of hallmark properties of malignant cells, and their toxic dose is typically much higher than the therapeutic one. In the present work we describe the mechanisms of the action of polyphenols on cancer cells, including their effects on genetic and epigenetic instability, tumor-promoting inflammation, and altered microbiota.