Epigallocatechin-3-Gallate Prevents the Acquisition of a Cancer Stem Cell Phenotype in Ovarian Cancer Tumorspheres through the Inhibition of Src/JAK/STAT3 Signaling

Cancer chemoprevention: signaling pathways and strategic approaches

Although cancer chemopreventive agents have been confirmed to effectively protect high-risk populations from cancer invasion or recurrence, only over ten drugs have been approved by the U.S. Food and Drug Administration. Therefore, screening potent cancer chemopreventive agents is crucial to reduce the constantly increasing incidence and mortality rate of cancer. Considering the lengthy prevention process, an ideal chemopreventive agent should be nontoxic, inexpensive, and oral. Natural compounds have become a natural treasure reservoir for cancer chemoprevention because of their superior ease of availability, cost-effectiveness, and safety. The benefits of natural compounds as chemopreventive agents in cancer prevention have been confirmed in various studies. In light of this, the present review is intended to fully delineate the entire scope of cancer chemoprevention, and primarily focuses on various aspects of cancer chemoprevention based on natural compounds, specifically focusing on the mechanism of action of natural compounds in cancer prevention, and discussing in detail how they exert cancer prevention effects by affecting classical signaling pathways, immune checkpoints, and gut microbiome. We also introduce novel cancer chemoprevention strategies and summarize the role of natural compounds in improving chemotherapy regimens. Furthermore, we describe strategies for discovering anticancer compounds with low abundance and high activity, revealing the broad prospects of natural compounds in drug discovery for cancer chemoprevention. Moreover, we associate cancer chemoprevention with precision medicine, and discuss the challenges encountered in cancer chemoprevention. Finally, we emphasize the transformative potential of natural compounds in advancing the field of cancer chemoprevention and their ability to introduce more effective and less toxic preventive options for oncology.

Unveiling the Role of JAK2/STAT3 signaling in chemoresistance of gynecological cancers: From mechanisms to therapeutic implications

Gynecological cancers, encompassing ovarian, cervical, endometrial, vulvar, and vaginal cancers, present a significant global health burden due to high incidence rates and associated mortality. Among these, ovarian, cervical, and endometrial cancers are particularly challenging, characterized by late-stage diagnoses, distinct pathological features, and significant resistance to chemotherapy. A major contributor to treatment failure is chemoresistance, driven by multifactorial mechanisms such as dysregulation of apoptosis, DNA repair, metabolic reprogramming, and the tumor microenvironment. The Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway plays a pivotal role in promoting chemoresistance, enhancing tumor cell survival, stemness, and immune evasion through the transcriptional regulation of anti-apoptotic and multidrug resistance genes. Persistent activation of this pathway not only sustains tumor progression but also limits the efficacy of standard chemotherapeutics, such as paclitaxel, cisplatin, and platinum-based agents. This review comprehensively examines the molecular mechanisms underlying JAK2/STAT3-mediated chemoresistance in gynecological cancers, highlighting its interactions with critical regulatory networks, including non-coding RNAs, cytokine signaling, hypoxia, and extracellular vesicles. We further explore therapeutic interventions targeting the JAK2/STAT3 axis, encompassing small molecule inhibitors, monoclonal antibodies, nanoparticles, and oncolytic viruses. Natural products and synthetic compounds targeting this pathway demonstrate significant potential in overcoming resistance and improving chemotherapy response. The findings underscore the critical role of JAK2/STAT3 signaling in the persistence and progression of chemoresistant gynecological cancers and advocate for the integration of pathway-targeted therapies into current treatment paradigms. By disrupting this axis, emerging therapies offer a promising strategy to enhance drug sensitivity and improve patient outcomes, paving the way for more effective and personalized approaches in gynecological oncology.

Oncometabolite D-2HG drives tumor metastasis and protumoral macrophage polarization by targeting FTO/m6A/ANGPTL4/integrin axis in triple-negative breast cancer

BACKGROUND

D-2-hydroxyglutarate (D-2HG), an oncometabolite derived from the tricarboxylic acid cycle. Previous studies have reported the diverse effects of D-2HG in pathophysiological processes, yet its role in breast cancer remains largely unexplored.

METHODS

We applied an advanced biosensor approach to detect the D-2HG levels in breast cancer samples. We then investigated the biological functions of D-2HG through multiple in vitro and in vivo assays. A joint MeRIP-seq and RNA-seq strategy was used to identify the target genes regulated by D-2HG-mediated N6-methyladenosine (m6A) modification. RNA pull-down assays were further applied to identify the reader that could specifically recognize the m6A modification on angiopoietin like 4 (ANGPTL4) mRNA and RNA immunoprecipitation was used to confirm the findings.

RESULTS

We found that D-2HG accumulated in triple-negative breast cancer (TNBC), exerting oncogenic effects both in vitro and in vivo by promoting TNBC cell growth and metastasis. Mechanistically, D-2HG enhanced global m6A RNA modifications in TNBC cells, notably upregulating m6A modification on ANGPTL4 mRNA, which was mediated by the inhibition of Fat-mass and obesity-associated protein (FTO), resulting in increased recognition of m6A-modified ANGPTL4 by YTH N6-methyladenosine RNA binding protein F1 (YTHDF1), thereby promoting the enhanced translation of ANGPTL4. As a secretory protein, ANGPTL4 subsequently activated the integrin-mediated JAK2/STAT3 signaling cascade in TNBC cells through autocrine signaling. Notably, the knockdown of ANGPTL4 or treatment with GLPG1087 (an integrin antagonist) significantly reduced D-2HG-induced proliferation and metastasis in TNBC cells. Additionally, ANGPTL4 was found to promote macrophage M2 polarization within the tumor microenvironment via paracrine signaling, further driving TNBC progression. The association of ANGPTL4 with poor prognosis in TNBC patients underscores its clinical relevance.

CONCLUSIONS

Our study unveils a previously unrecognized role for D-2HG-mediated RNA modification in TNBC progression and targeting the D-2HG/FTO/m6A/ANGPTL4/integrin axis can serve as a promising therapeutic target for TNBC patients.

Role of Epigallocatechin Gallate in Selected Malignant Neoplasms in Women

Tea is a significant source of flavonoids in the diet. Due to different production processes, the amount of bioactive compounds in unfermented (green) and (semi-)fermented tea differs. Importantly, green tea has a similar composition of phenolic compounds to fresh, unprocessed tea leaves. It consists primarily of monomeric flavan-3-ols, known as catechins, of which epigallocatechin gallate (EGCG) is the most abundant. Thanks to its antioxidant, antiproliferative, and antiangiogenic properties, EGCG has attracted the scientific community's attention to its potential use in preventing and/or combating cancer. In this review article, we summarize the literature reports found in the Google Scholar and PubMed databases on the anticancer effect of EGCG on selected malignant neoplasms in women, i.e., breast, cervical, endometrial, and ovarian cancers, which have been published over the last two decades. It needs to be emphasized that EGCG concentrations reported as effective against cancer cells are typically higher than those found in plasma after polyphenol administration. Moreover, the low bioavailability and absorption of EGCG appear to be the main reasons for the differences in the effects between in vitro and in vivo studies. In this context, we also decided to look at possible solutions to these problems, consisting of combining the polyphenol with other bioactive components or using nanotechnology. Despite the promising results of the studies conducted so far, mainly in vitro and on animal models, there is no doubt that further, broad-based activities are necessary to unequivocally assess the potential use of EGCG in oncological treatment to combat cancer in women.

The interplay of exercise and green tea: a new road in cancer therapy

Exercise is one of the most important activities for every individual due to its proven health beneficials. Several investigations have highlighted the advantageous impacts of aerobic exercise, largely attributed to its capacity to enhance the body's capability to defend against threats against oxidative stress. The information currently accessible suggests that adding regular aerobic exercise to a daily routine greatly decreases the chances of developing serious cancer and passing away. An unevenness in the levels of free radicals and the body's antioxidant defenses, made up of enzyme and non-enzyme antioxidants, results in oxidative pressure. Generally, an imbalance in the levels of oxidative stress triggers the creation of harmful reactive oxygen or nitrogen compounds, causing the development or progression of numerous ailments, including cancer. The equilibrium between pro-oxidant and antioxidant substances is a direct indicator of this imbalance. Green tea and its derivatives are rich sources of bioactive substances such as flavonoids and polyphenols which possess antioxidant abilities. Moreover, modulation of epigenetic targets as well as inflammatory pathways including ERK1/2 and NF-κB are other proposed mechanisms for its antioxidant activity. Recent studies demonstrate the promise of green tea as an antioxidant, showing its ability to decrease the likelihood of developing cancer by impacting actions like cell growth, blood vessel formation, and spread of cancer cells. This summary will concentrate on the complex network of different pathways related to physical activity and consumption of green tea. In particular, the focus of this research will be on examining how oxidative stress contributes to health and investigating the potential antioxidant properties of green tea, and the interconnected relationship between exercise and green tea in the treatment of cancer. Elucidation of these different pathways would help scientists for development of better therapeutic targets and further increase of current anticancer agents efficiency.

Structure, function, signaling pathways and clinical therapeutics: The translational potential of STAT3 as a target for cancer therapy

Cancer remains one of the most difficult human diseases to overcome because of its complexity and diversity. Signal transducers and transcriptional activators 3 (STAT3) protein has been found to be overexpressed in a wide range of cancer types. Hyperactivation of STAT3 is particularly associated with low survival in cancer patients. This review summarizes the specific molecular mechanisms of STAT3 in cancer development. STAT3 is activated by extracellular signals in the cytoplasm, interacts with different enzymes in the nucleus, mitochondria or endoplasmic reticulum, and subsequently participates in cancer development. The phosphorylated STAT3 at tyrosine 705 site (YP-STAT3) enters the nucleus and regulates a number of tumor-related biological processes such as angiogenesis, migration invasion, cell proliferation and cancer cell stemness. In contrast, the phosphorylated STAT3 at serine 727 site (SP-STAT3) is found on the mitochondria, affects electron respiration transport chain activity and thereby prevents tumor cell apoptosis. SP-STAT3 also appears on the mitochondria-associated endoplasmic reticulum membrane, influences the flow of Ca2+, and affects tumor progression. In addition, we summarize the direct and indirect inhibitors of STAT3 which are currently undergoing clinical studies. Some of them such as TTI101 and BBI608 have been approved by the FDA for the treatment of certain cancers. All in all, STAT3 plays an important role in cancer progression and becomes a potential target for cancer treatment.

The Chemopreventive Impact of Diet-Derived Phytochemicals on the Adipose Tissue and Breast Tumor Microenvironment Secretome

Cancer cells-derived extracellular vesicles can trigger the transformation of adipose-derived mesenchymal stem cells (ADMSC) into a pro-inflammatory, cancer-associated adipocyte (CAA) phenotype. Such secretome-mediated crosstalk between the adipose tissue and the tumor microenvironment (TME) therefore impacts tumor progression and metastatic processes. In addition, emerging roles of diet-derived phytochemicals, especially epigallocatechin-3-gallate (EGCG) among other polyphenols, in modulating exosome-mediated metabolic and inflammatory signaling pathways have been highlighted. Here, we discuss how selected diet-derived phytochemicals could alter the secretome signature as well as the crosstalk dynamics between the adipose tissue and the TME, with a focus on breast cancer. Their broader implication in the chemoprevention of obesity-related cancers is also discussed.

Thermo-Responsive Hydrogel Based on Lung Decellularized Extracellular Matrix for 3D Culture Model to Enhance Cancer Stem Cell Characteristics

Cancer stem cells (CSCs) are most likely the main cause of lung cancer formation, metastasis, drug resistance, and genetic heterogeneity. Three-dimensional (3D) ex vivo cell culture models can facilitate stemness improvement and CSC enrichment. Considering the critical role of extracellular matrix (ECM) on CSC properties, the present study developed a thermo-responsive hydrogel using the porcine decellularized lung for 3D cell culture, and the cell-laden hydrogel culturing model was used to explore the CSC characteristics and potential utilization in CSC-specific drug evaluation. Results showed that the lung dECM hydrogel (LEH) was composed of the main ECM components and displayed excellent cellular compatibility. In addition, lung cancer cells 3D cultured in LEH displayed the overexpression of metastasis-related genes and enhanced migration properties, as compared with those in two-dimensional (2D) conditions. Notably, the CSC features, including the expression level of stemness-associated genes, colony formation capability, drug resistance, and the proportion of cancer stem-like cells (CD133+), were also enhanced in 3D cells. Furthermore, the attenuation effect of epigallocatechin gallate (EGCG) on CSC properties in the 3D model was observed, confirming the potential practicability of the 3D culture on CSC-targeted drug screening. Overall, our results suggest that the fabricated LEH is an effective and facile platform for 3D cell culture and CSC-specific drug evaluation.

Cancer-associated adipocytes in the ovarian cancer microenvironment

The tumor microenvironment (TME) plays a critical role in high energy metabolism during tumorigenesis, progression and metastasis. Among them, adipocytes, as an important component of the TME, can transform into cancer-associated adipocytes (CAAs) through dedifferentiation via interactions with tumor cells. These CAAs provide nutrients, growth factors, cytokines and metabolites to the tumor and later transdifferentiate into other stromal cells at a later stage to alter tumor growth, metastasis and the drug response and ultimately influence the treatment and prognosis of ovarian cancer. This review outlines the physiological functions of CAAs and discusses the progress in the use of CAAs as therapeutic targets in ovarian cancer.

STAT3 promotes cytoplasmic-nuclear translocation of RNA-binding protein HuR to inhibit IL-1β-induced IL-8 production

Signal transducer and activator of transcription 3 (STAT3) functions to regulate inflammation and immune response, but its mechanism is not fully understood. We report here that STAT3 inhibitors Stattic and Niclosamide up-regulated IL-1β-induced IL-8 production in C33A, CaSki, and Siha cervical cancer cells. As expected, IL-1β-induced IL-8 production was also up-regulated through the molecular inhibition of STAT3 by use of CRISPR/Cas9 technology. Unexpectedly, IL-1β induced IL-8 production via activating ERK and P38 signal pathways, but neither STAT3 inhibitors nor STAT3 knockout affected IL-1β-induced signal transduction, suggesting that STAT3 decreases IL-8 production not via inhibition of signal transduction. To our surprise, STAT3 inhibition increased the stabilization, and decreased the degradation of IL-8 mRNA, suggesting a post-transcriptional regulation of IL-1β-induced IL-8. Moreover, Dihydrotanshinone I, an inhibitor of RNA-binding protein HuR, down-regulated IL-1β-induced IL-8 dose-dependently. HuR inhibition by CRISPR/Cas9 also decreased IL-8 production induced by IL-1β. Mechanistically, co-immunoprecipitation results showed that STAT3 did not react with HuR directly, but STAT3 inhibition increased the protein levels of HuR in cytoplasm. And IL-6 activation of STAT3 induced HuR cytoplasmic-nuclear transport. Taken together, these results suggest that STAT3 contributes to HuR nuclear localization and inhibits Il-1β-induced IL-8 production through this non-transcriptional mechanism.

Exploring the Apoptotic-Induced Biochemical Mechanism of Traditional Thai Herb (Kerra™) Extract in HCT116 Cells Using a Label-Free Proteomics Approach

Background and Objectives: Natural products have proven to be a valuable source for the discovery of new candidate drugs for cancer treatment. This study aims to investigate the potential therapeutic effects of "Kerra™", a natural extract derived from a mixture of nine medicinal plants mentioned in the ancient Thai scripture named the Takxila Scripture, on HCT116 cells. Materials and Methods: In this study, the effect of the Kerra™ extract on cancer cells was assessed through cell viability assays. Apoptotic activity was evaluated by examining the apoptosis characteristic features. A proteomics analysis was conducted to identify proteins and pathways associated with the extract's mechanism of action. The expression levels of apoptotic protein markers were measured to validate the extract's efficacy. Results: The Kerra™ extract demonstrated a dose-dependent inhibitory effect on the cells, with higher concentrations leading to decreased cell viability. Treatment with the extract for 72 h induced characteristic features of early and late apoptosis, as well as cell death. An LC-MS/MS analysis identified a total of 3406 proteins. The pathway analysis revealed that the Kerra™ extract stimulated apoptosis and cell death in colorectal cancer cell lines and suppressed cell proliferation in adenocarcinoma cell lines through the EIF2 signaling pathway. Upstream regulatory proteins, including cyclin-dependent kinase inhibitor 1A (CDKN1A) and MYC proto-oncogene, bHLH transcription factor (MYC), were identified. The expressions of caspase-8 and caspase-9 were significantly elevated by the Kerra™ extract compared to the chemotherapy drug Doxorubicin (Dox). Conclusions: These findings provide strong evidence for the ability of the Kerra™ extract to induce apoptosis in HCT116 colon cancer cells. The extract's efficacy was demonstrated by its dose-dependent inhibitory effect, induction of apoptotic activity, and modulation of key proteins involved in cell death and proliferation pathways. This study highlights the potential of Kerra™ as a promising therapeutic agent in cancer treatment.