Epigallocatechin-3-gallate shows anti-proliferative activity in HeLa cells targeting tubulin-microtubule equilibrium

Epigallocatechin Gallate for the Treatment of Benign and Malignant Gynecological Diseases-Focus on Epigenetic Mechanisms

The most common malignant gynecologic diseases are cervical, uterine, ovarian, vaginal, and vulvar cancer. Among them, ovarian cancer causes more deaths than any other cancer of the female reproductive system. A great number of women suffer from endometriosis, uterine fibroids (UFs), adenomyosis, dysmenorrhea, and polycystic ovary syndrome (PCOS), which are widespread benign health problems causing troublesome and painful symptoms and significantly impairing the quality of life of affected women, and they are some of the main causes of infertility. In addition to the available surgical and pharmacological options, the effects of supporting standard treatment with naturally occurring compounds, mainly polyphenols, are being studied. Catechins are responsible for the majority of potential health benefits attributed to green tea consumption. Epigallocatechin gallate (EGCG) is considered a non-toxic, natural compound with potential anticancer properties. Antioxidant action is its most common function, but attention is also drawn to its participation in cell division inhibition, apoptosis stimulation and epigenetic regulation. In this narrative review, we describe the role of EGCG consumption in preventing the development of benign reproductive disorders such as UF, endometriosis, and PCOS, as well as malignant gynecologic conditions. We discuss possible epigenetic mechanisms that may be related to the action of EGCG.

Epigallocatechin-3-gallate and its nanoformulation in cervical cancer therapy: the role of genes, MicroRNA and DNA methylation patterns

Green tea, a popular and healthy nonalcoholic drink consumed globally, is abundant in natural polyphenols. One of these polyphenols is epigallocatechin-3-gallate (EGCG), which offers a range of health benefits, such as metabolic regulation, antioxidant properties, anti-inflammatory effects, and potential anticancer properties. Clinical research has shown that EGCG can inhibit cancers in the male and female reproductive systems, including ovarian, cervical, endometrial, breast, testicular, and prostate cancers. Further research on cervical cancer has revealed the crucial role of epigenetic mechanisms in the initiation and progression of this type of cancer. These include changes to the DNA, histones, and non-coding RNAs, such as microRNAs. These changes are reversible and can occur even before genetic mutations, making them a potential target for intervention therapies. One promising approach to cancer prevention and treatment is the use of specific agents (known as epi-drugs) that target the cancer epigenome or epigenetic dysregulation. Phytochemicals, a group of diverse molecules, have shown potential in modulating cancer processes through their interaction with the epigenetic machinery. Among these, green tea and its main polyphenol EGCG have been extensively studied. This review highlights the therapeutic effects of EGCG and its nanoformulations on cervical cancer. It also discusses the epigenetic events involved in cervical cancer, such as DNA methylation and microRNA dysregulation, which may be affected by EGCG.

Heavy water (D2O) induces autophagy-dependent apoptotic cell death in non-small cell lung cancer A549 cells by generating reactive oxygen species (ROS) upon microtubule disruption

OBJECTIVE

Deuterium oxide (D2O) or heavy water is known to have diverse biological activities and have a few therapeutic applications due to its limited toxicity to human subjects. In the present study, we investigated the mechanism of D2O-induced cytotoxicity in non-small cell lung cancer A549 cells.

RESULTS

We found that D2O-treatment resulted in cytotoxicity, cell cycle arrest, and apoptosis in A549 cells in a dose-dependent fashion. In contrast, limited cytotoxicity was observed in lung fibroblasts WI38 cells. Moreover, D2O-treatment resulted in the disruption of the cellular microtubule network, accompanied by the generation of ROS. On further investigation, we observed that the intracellular ROS triggered autophagic responses in D2O-treated cells, leading to apoptosis by inhibiting the oncogenic PI3K/ Akt/ mTOR signaling. D2O-treatment was also found to enhance the efficacy of paclitaxel in A549 cells.

SIGNIFICANCE

D2O induces autophagy-dependent apoptosis in A549 cells via ROS generation upon microtubule depolymerization and inhibition of PI3K/ Akt/ mTOR signaling. It augments the efficacy of other microtubule-targeting anticancer drug taxol, which indicates the potential therapeutic importance of D2O as an anticancer agent either alone or in combination with other chemotherapeutic drugs.

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.

Preventing Persistence of HPV Infection with Natural Molecules

Human papillomavirus (HPV) infection is one the most common sexually transmitted infections worldwide. In most cases, the infection is temporary and asymptomatic; however, when persistent, it may lead to lesions that can evolve into cancer in both women and men. Nowadays, prophylactic vaccination is the primary preventive strategy for HPV infections, but vaccines do not cover all types of HPV strains. Scientific research has uncovered the beneficial role of some natural supplements in preventing persistent HPV infections or treating HPV-related lesions. We review the current insight into the roles of natural molecules in HPV infection with a special focus on epigallocatechin gallate (EGCG), folic acid, vitamin B12, and hyaluronic acid (HA). Specifically, EGCG from green tea extracts plays a critical role in suppressing HPV oncogenes and oncoproteins (E6/E7), which are responsible for HPV oncogenic activity and cancer development. Folic acid and vitamin B12 are essential vitamins for multiple functions in the body, and accumulating evidence suggests their importance in maintaining a high degree of methylation of the HPV genome, thus decreasing the likelihood of causing malignant lesions. HA, due to its re-epithelizing property, may prevent HPV virus entry in damaged mucosa and epithelia. Thereby, based on these premises, the combination of EGCG, folic acid, vitamin B12, and HA may be a very promising therapeutic approach to prevent HPV persistence.

Green Tea in Reproductive Cancers: Could Treatment Be as Simple?

Green tea originates from the tea plant Camellia sinensis and is one of the most widely consumed beverages worldwide. Green tea polyphenols, commonly known as catechins, are the major bioactive ingredients and account for green tea's unique health benefits. Epigallocatechin-3-gallate (EGCG), is the most potent catechin derivative and has been widely studied for its pro- and anti-oxidative effects. This review summarizes the chemical and chemopreventive properties of green tea in the context of female reproductive cancers. A comprehensive search of PubMed and Google Scholar up to December 2022 was conducted. All original and review articles related to green tea or EGCG, and gynecological cancers published in English were included. The findings of several in vitro, in vivo, and epidemiological studies examining the effect of green tea on reproductive cancers, including ovarian, cervical, endometrial, and vulvar cancers, are presented. Studies have shown that this compound targets specific receptors and intracellular signaling pathways involved in cancer pathogenesis. The potential benefits of using green tea in the treatment of reproductive cancers, alone or in conjunction with chemotherapeutic agents, are examined, shedding light on new therapeutic strategies for the management of female reproductive cancers.

The Effect of Gambier Catechin Isolate on Cervical Cancer Cell Death (HeLa Cell Lines)

BACKGROUND: Cervical cancer is the second most common type of cancer in women worldwide. Human Papilloma Virus infection on the surface of the cervix is the most common cause which can cause abnormal growth of cervical cells. AIM: This research was conducted in vitro which aims to determine whether catechin compounds can inhibit the growth and regulation of cervical cancer cells (HeLa cell line). METHODS: This is experimental research using the colourimetric assay method and qualitative observation of cervical cancer cell morphology (HeLa cell line) under a fluorescence microscope. The administration of catechin compounds was tested at different concentrations to HeLa cells, namely 1000 g/ml, 500 g/ml, 250 g/ml, 125 g/ml, 62.5 g/ml, 31.25 g/ml. RESULTS: The smallest cell viability was obtained from a concentration of 1000 g/ml which was 5.98% while the largest cell viability was found at a concentration of 31.25 g/ml, which was 40.01%. The resulting IC50 value was 22.91 g/ml. Gambier catechin compounds have very high antioxidants because they contain an IC50 value < 50 g/ml. The effect of gambier catechin compounds on HeLa cell death can be found by increasing the percentage of dead cells. The difference in the fluorescence images of HeLa cells in the experimental group was assessed based on the percentage of the number of cells that died or underwent apoptosis, which was marked by a red or orange fluorescent image. At the concentration of IC25, 31.87% of dead cells were found, the concentration of IC50 was 51.09% of dead cells, and the concentration of IC75 was 82.51% of dead cells. The test results showed that there was a significant difference in the average percentage of cells undergoing apoptosis in all study groups with p <0.05. CONCLUSION: Based on research, it can be concluded that catechin compounds could inhibit the growth and regulation of cervical cancer cells (HeLa cell line). Later, it has the potential to be developed as an anticancer candidate for cervical cancer. Keyword: Cervical cancer, Catechin, Apoptosis, HeLa cell line, Cell death.

An In-Silico, In-Vitro and In-Vivo Combined Approach to Identify NMNATs as Potential Protein Targets of ProEGCG for Treatment of Endometriosis

Endometriosis is defined as endometrial tissues found outside the uterine cavity. ProEGCG is a prodrug of Epigallocatechin gallate (EGCG), a potent polyphenol found in green tea. It inhibits the development of endometriotic lesions of mouse model in vivo, with higher efficacy and more remarkable anti-oxidative ability than EGCG. Our study aims to identify the molecular binding targets and pharmacological actions of ProEGCG in treating endometriosis. Protein target interaction study is essential to fully characterize the mechanism of actions, related therapeutic effects, and side effects. We employed a combined approach, starting with an in silico reverse screening of protein targets and molecular docking, followed by in vitro cellular thermal shift assay (CESTA) to assess the stability of protein-small molecule complexes. Then microarray and immunostaining of endometriotic lesions in mice in vivo confirmed the molecular interaction of the selected targets after treatment. Our study identified enzymes nicotinamide nucleotide adenylyltransferase (NMNAT)1 and NMNAT3 as protein targets of ProEGCG in silico and in vitro and were overexpressed after ProEGCG treatment in vivo. These findings suggested that participation in nicotinate and nicotinamide metabolism potentially regulated the redox status of endometriosis via its antioxidative capacities through binding to the potential therapeutic targets of ProEGCG.

Co-Adjuvant Therapy Efficacy of Catechin and Procyanidin B2 with Docetaxel on Hormone-Related Cancers In Vitro

Prostate (PC) and breast cancer (BC) are heterogeneous hormonal cancers. Treatment resistance and adverse effects are the main limitations of conventional chemotherapy treatment. The use of sensitizing agents could improve the effectiveness of chemotherapeutic drugs as well as obviate these limitations. This study analyzes the effect of single catechin (CAT), procyanidin B2 (ProB2) treatment as well as the co-adjuvant treatment of each of these compounds with docetaxel (DOCE). We used PC- and BC-derived cell lines (PC3, DU-145, T47D, MCF-7 and MDA-MB-231). The short and long-term pro-apoptotic, anti-proliferative and anti-migratory effects were analyzed. RT-qPCR was used to discover molecular bases of the therapeutic efficacy of these compounds. ProB2 treatment induced a two- to five-fold increase in anti-proliferative and pro-apoptotic effects compared to single DOCE treatment, and also had a more sensitizing effect than DOCE on DU145 cells. Regarding BC cells, ProB2- and CAT-mediated sensitization to DOCE anti-proliferative and pro-apoptotic effects was cell-independent and cell-dependent, respectively. Combined treatment led to high-efficacy effects on MCF-7 cells, which were associated to the up-regulation of CDKN1A, BAX, caspase 9 and E-cadherin mRNA under combined treatment compared to single DOCE treatment. CAT and ProB2 can enhance the efficacy of DOCE therapy on PC and BC cells by the sensitizing mechanism.

Induced Cell Death as a Possible Pathway of Antimutagenic Action

The existing concepts of antimutagenesis are briefly reviewed. Published reports on antimutagenic and proapoptotic properties of some polyphenols and compounds of other chemical groups obtained in representative in vitro and in vivo experiments on eukaryotic test systems are discussed. The relationships between the antimutagenic and proapoptotic properties of the analyzed compounds (naringin, apigenin, resveratrol, curcumin, N-acetylcysteine, etc.) are considered in favor of the hypothesis on induced cell death as an antimutagenic tool.

Natural flavonoid morin showed anti-bacterial activity against Vibrio cholera after binding with cell division protein FtsA near ATP binding site

BACKGROUND

Increasing antibiotic-resistance in bacterial strains has boosted the need to find new targets for drug delivery. FtsA, a major bacterial divisome protein can be a potent novel drug-target.

METHODS AND RESULTS

This study finds, morin (3,5,7,2',4'-pentahydroxyflavone), a bio-available flavonoid, had anti-bacterial activities against Vibrio cholerae, IC₅₀ (50 μM) and MIC (150 μM). Morin (2 mM) kills ~20% of human lung fibroblast (WI38) and human intestinal epithelial (HIEC-6) cells in 24 h in-vitro. Fluorescence studies showed morin binds to VcFtsA (FtsA of V. cholerae) with a K_d of 4.68 ± 0.4 μM, inhibiting the protein's polymerization by 72 ± 7% at 25 μM concentration. Morin also affected VcFtsA's ATPase activity, recording ~80% reduction at 20 μM concentration. The in-silico binding study indicated binding sites of morin and ATP on VcFtsA had overlapping amino acids. Mant-ATP, a fluorescent ATP-derivative, showed increased fluorescence on binding to VcFtsA in absence of morin, but in its presence, Mant-ATP fluorescence decreased. VcFtsA-S40A mutant protein did not bind to morin.

CONCLUSIONS

VcFtsA-morin interaction inhibits the polymerization of the protein by affecting its ATPase activity. The destabilized VcFtsA assembly in-turn affected the cell division in V. cholerae, yielding an elongated morphology.

GENERAL SIGNIFICANCE

Collectively, these findings explore the anti-bacterial effect of morin on V. cholerae cells targeting VcFtsA, encouraging it to become a potent anti-bacterial agent. Low cytotoxicity of morin against human cells (host) is therapeutically advantageous. This study will also help in synthesizing novel derivatives that can target VcFtsA more efficiently.

Evaluation of Dimer of Epicatechin from an Endophytic Fungus Curvularia australiensis FC2AP on Acute Toxicity Levels, Anti-Inflammatory and Anti-Cervical Cancer Activity in Animal Models

Cervical cancer, as the most frequent cancer in women globally and accounts almost 14% in India. It can be prevented or treated with vaccines, radiation, chemotherapy, and brachytherapy. The chemotherapeutic agents cause adverse post effects by the destruction of the neighboring normal cells or altering the properties of the cells. In order to reduce the severity of the side effects caused by the chemically synthesized therapeutic agents, the current research developed an anti-cancer agent dimer of epicatechin (DoE), a natural bioactive secondary metabolite (BSM) mediated from an endophytic fungus Curvularia australiensis FC2AP. The investigation has initiated with the evaluation of inhibiting the angiogenesis which is a main activity in metastasis, and it was assessed through Hen’s Egg Test on Chorio Allantoic Membrane (HET-CAM) test; the BSM inhibited the growth of blood vessels in the developing chick embryo. Further the DoE was evaluated for its acute toxicity levels in albino mice, whereas the survival dose was found to be 1250 mg/kg and the lethal dose was 1500 mg/kg body weight of albino mice; hematological, biochemical, and histopathological analyses were assessed. The anti-inflammatory responses of the DoE were evaluated in carrageenan induced Wistar rats and the reduction of inflammation occurred in a dose-dependent manner. By fixing the effective dose for anti-inflammation analysis, the DoE was taken for the anti-cervical cancer analysis in benzo (a) pyrene induced female Sprague-Dawley rats for 60 days trial. After the stipulated days, the rats were taken for hematological antioxidants, lipid peroxidation (LPO), member bound enzymes, cervical histopathological and carcinogenic markers analyses. The results specified that the DoE has the capability of reducing the tumor in an efficient way. This is the first report of flavonoid-DoE production from an endophytic fungus C. australiensis has the anticancer potentiality and it can be stated as anti-cancer drug.

FtsA-FtsZ interaction in Vibrio cholerae causes conformational change of FtsA resulting in inhibition of ATP hydrolysis and polymerization

Proper interaction between the divisome proteins FtsA and FtsZ is important for the bacterial cell division which is not well characterized till date. In this study, the objective was to understand the mechanism of FtsA-FtsZ interaction using full-length recombinant proteins. We cloned, over-expressed, purified and subsequently characterized FtsA of Vibrio cholerae (VcFtsA). We found that VcFtsA polymerization assembly was dependent on Ca²⁺ ions, which is unique among FtsA proteins reported until now. VcFtsA also showed ATPase activity and its assembly was ATP dependent. Binding parameters of the interaction between the two full-length proteins, VcFtsA, and VcFtsZ determined by fluorescence spectrophotometry yielded a K_d value of around 38 μM. The K_d value of the interaction was 3 μM when VcFtsA was in ATP bound state. We found that VcFtsZ after interacting with VcFtsA causes a change of secondary structure in the later one leading to loss of its ability to hydrolyze ATP, subsequently halting the VcFtsA polymerization. On the other hand, a double-mutant of VcFtsA (VcFtsA-D242E,R300E), that does not bind to VcFtsZ, polymerized in the presence of VcFtsZ. Though FtsA proteins among different organisms show 70-80% homology in their sequences, assembly of VcFtsA showed a difference in its regulatory processes.

Alchemilla vulgaris agg. (Lady's mantle) from central Balkan: antioxidant, anticancer and enzyme inhibition properties

The current study was designed to evaluate the phytochemical profile and biological properties (antioxidant, enzyme inhibitory and cytotoxic activity) of methanolic, ethanolic, ethyl-acetate and water extracts of Alchemilla vulgaris from Southeast Serbia (central Balkan) which was traditionally used to alleviate and treat many diseases. Bioactive compounds were characterized by LC-MS/MS technique and biological properties were evaluated using antioxidant, enzyme inhibitory and cytotoxic assays. Twenty-six phenolic compounds were quantified in methanolic, ethanolic, ethyl acetate and water extracts, whereas the highest yields were found in ethyl-acetate (EA) extract (gallic acid, caffeic acid, catchin, quercetin). This extract has also shown the greatest antioxidant, anticancer and inhibitory enzyme activities which were demonstrated for the first time in this study. The obtained results indicated that Alchemilla vulgaris from South Serbia possesses high potential for pharmaceutical applications.

Boronic acid copolymers for direct loading and acid-triggered release of Bis-T-23 in cultured podocytes

We report an acid-reversible linker for triggered release of Bis-T-23, an experimental small molecule drug for kidney disease treatment that restores podocyte morphology during disease. Bis-T-23 contains catechols, which form an acid-reversible, covalent boronate ester bond with boronic acids. We synthesized phenylboronic acid-containing polymers using reversible addition-fragmentation chain transfer polymerization that were able to directly load and solubilize Bis-T-23. Because of the reversibility of the boronic ester bond, drug was released in its native form in a pH-dependent manner. The polymers rapidly trafficked into acidic compartments and did not exhibit cytotoxicity, and polymer-drug conjugates successfully delivered Bis-T-23 into cultured podocytes.

Molecular Targets of Epigallocatechin-Gallate (EGCG): A Special Focus on Signal Transduction and Cancer

Green tea is a beverage that is widely consumed worldwide and is believed to exert effects on different diseases, including cancer. The major components of green tea are catechins, a family of polyphenols. Among them, epigallocatechin-gallate (EGCG) is the most abundant and biologically active. EGCG is widely studied for its anti-cancer properties. However, the cellular and molecular mechanisms explaining its action have not been completely understood, yet. EGCG is effective in vivo at micromolar concentrations, suggesting that its action is mediated by interaction with specific targets that are involved in the regulation of crucial steps of cell proliferation, survival, and metastatic spread. Recently, several proteins have been identified as EGCG direct interactors. Among them, the trans-membrane receptor 67LR has been identified as a high affinity EGCG receptor. 67LR is a master regulator of many pathways affecting cell proliferation or apoptosis, also regulating cancer stem cells (CSCs) activity. EGCG was also found to be interacting directly with Pin1, TGFR-II, and metalloproteinases (MMPs) (mainly MMP2 and MMP9), which respectively regulate EGCG-dependent inhibition of NF-kB, epithelial-mesenchimal transaction (EMT) and cellular invasion. EGCG interacts with DNA methyltransferases (DNMTs) and histone deacetylases (HDACs), which modulates epigenetic changes. The bulk of this novel knowledge provides information about the mechanisms of action of EGCG and may explain its onco-suppressive function. The identification of crucial signalling pathways that are related to cancer onset and progression whose master regulators interacts with EGCG may disclose intriguing pharmacological targets, and eventually lead to novel combined treatments in which EGCG acts synergistically with known drugs.

Theaflavin and epigallocatechin-3-gallate synergistically induce apoptosis through inhibition of PI3K/Akt signaling upon depolymerizing microtubules in HeLa cells

Theaflavin (TF) and epigallocatechin-3-gallate (EGCG) both have been reported previously as microtubule depolymerizing agents that also have anticancer effects on various cancer cell lines and in animal models. Here, we have applied TF and EGCG in combination on HeLa cells to investigate if they can potentiate each other to improve their anticancer effect in lower doses and the underlying mechanism. We found that TF and EGCG acted synergistically, in lower doses, to inhibit the growth of HeLa cells. We found the combination of 50 µg/mL TF and 20 µg/mL EGCG to be the most effective combination with a combination index of 0.28. The same combination caused larger accumulation of cells in the G ₂ /M phase of the cell cycle, potent mitochondrial membrane potential loss, and synergistic augmentation of apoptosis. We have shown that synergistic activity might be due to stronger microtubule depolymerization by simultaneous binding of TF and EGCG at different sites on tubulin: TF binds at vinblastine binding site on tubulin, and EGCG binds near colchicines binding site on tubulin. A detailed mechanistic analysis revealed that stronger microtubule depolymerization caused effective downregulation of PI3K/Akt signaling and potently induced mitochondrial apoptotic signals, which ultimately resulted in the apoptotic death of HeLa cells in a synergistic manner.

Orthosiphon stamineus Extracts Inhibits Proliferation and Induces Apoptosis in Uterine Fibroid Cells

Objectives: The effects of water and 50% ethanolic-water extracts of Orthosiphon stamineus Benth (OS) on cell proliferation and apoptotic activity against uterine leiomyosarcoma (SK-UT-1) cells were investigated. Methods: Anti-proliferation effect was evaluated through cell cycle analysis whereas apoptotic activity was determined via screening and quantifying using fluorescence microscopy and flow cytometric analysis, respectively. The effect of extracts on molecular mechanism was studied using real-time reverse transcription polymerase chain reaction and Western blotting. Results: Cell cycle flow cytometric analysis showed the induction of cell cycle arrests were behaves in a p53-independent manner. The examination using fluorescence microscopy and Annexin V flow cytometry revealed the presence of morphological features of apoptotic bodies. Downregulation of anti-apoptotic gene (Bcl-2) supports the apoptotic activity of OS extracts although poorly induce PARP-1 cleavage in Western blot analysis. The extracts also inhibit the SK-UT-1 growth by suppressing VEGF-A, TGF-β1 and PCNA genes, which involved in angiogenesis and cell proliferation. Conclusion: This study demonstrates that O. stamineus extracts are able to inhibit proliferation and induced apoptosis of uterine fibroid cells and is worth further investigation.

Suppressive Effects of EGCG on Cervical Cancer

Cervical cancer is the fourth most common gynecological cancer worldwide. Although prophylactic vaccination presents the most effective method for cervical cancer prevention, chemotherapy is still the primary invasive intervention. It is urgent to exploit low-toxic natural anticancer drugs on account of high cytotoxicity and side-effects of conventional agents. As a natural product, (-)-epigallocatechingallate (EGCG) has abilities in anti-proliferation, anti-metastasis and pro-apoptosis of cervical cancer cells. Moreover, EGCG also has pharmaceutical synergistic effects with conventional agents such as cisplatin (CDDP) and bleomycin (BLM). The underlying mechanisms of EGCG suppressive effects on cervical cancer are reviewed in this article. Further research directions and ambiguous results are also discussed.

Inhibitory Activity of Catechin Metabolites Produced by Intestinal Microbiota on Proliferation of HeLa Cells

Eleven kinds of catechin metabolites produced from (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCg) by intestinal microbiota were evaluated for inhibitory activity on the proliferation of HeLa cells, which are human cervical cancer cells. Among the catechin metabolites, 1-(3,4,5-trihydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)propan-2-ol (EGC-M2), 4-hydroxy-5-(3,4,5-trihydroxyphenyl)valeric acid (EGC-M7), and 5-(3,4,5-trihydroxyphenyl)valeric acid (EGC-M9) were found to show inhibitory activity on HeLa cell proliferation as compared with control. The results suggested that three adjacent hydroxyl groups in the phenyl moiety may play an important role in the inhibitory activity. In addition, the inhibitory activity was also examined with four (-)-epicatechin (EC) metabolites possessing two adjacent hydroxyl groups in the phenyl moiety. Only 5-(3,4-dihydroxyphenyl)valeric acid (EC-M9) showed inhibitory activity and therefore valeric acid moiety likely contributes to the inhibitory activity. EGC-M9 showed the strongest inhibitory activity with IC₅₀ of 5.58 µM. Thus, in this study it was found for the first time that several catechin metabolites derived from EGC, EGCg, and EC inhibit the proliferation of cervical cancer cells.

Epigenetic actions of environmental factors and promising drugs for cancer therapy

Carcinogenesis is known to be primarily associated with gene mutations. Recently, increasing evidence has suggested that epigenetic events also serve crucial roles in tumor etiology. Environmental factors, including nutrition, toxicants and ethanol, are involved in carcinogenesis through inducing epigenetic modifications, such as DNA methylation, histone deacetylase and miRNA regulation. Studying epigenetic mechanisms has facilitated the development of early diagnostic strategies and potential therapeutic avenues. Modulation at the epigenetic level, including reversing epigenetic modifications using targeted drugs, has demonstrated promise in cancer therapy. Therefore, identifying novel epigenetic biomarkers and therapeutic targets has potential for the future of cancer therapy. The present review discusses the environmental factors involved in epigenetic modifications and potential drug candidates for cancer therapy.

Bothrops jararaca and Bothrops erythromelas Snake Venoms Promote Cell Cycle Arrest and Induce Apoptosis via the Mitochondrial Depolarization of Cervical Cancer Cells

Bothrops jararaca (BJ) and Bothrops erythromelas (BE) are viper snakes found in South-Southeast and Northeast regions of Brazil, respectively. Snake venoms are bioactive neurotoxic substances synthesized and stored by venom glands, with different physiological and pharmacological effects, recently suggesting a possible preference for targets in cancer cells; however, mechanisms of snakes have been little studied. Here, we investigated the mechanism responsible for snake crude venoms toxicity in cultured cervical cancer cells SiHa and HeLa. We show that BJ and BE snake crude venoms exert cytotoxic effects to these cells. The percentage of apoptotic cells and cell cycle analysis and cell proliferation were assessed by flow cytometry and MTT assay. Detection of mitochondrial membrane potential (Rhodamine-123), nuclei morphological change, and DNA fragmentation were examined by staining with DAPI. The results showed that both the BJ and BE venoms were capable of inhibiting tumor cell proliferation, promoting cytotoxicity and death by apoptosis of target SiHa and HeLa cells when treated with BJ and BE venoms. Furthermore, data revealed that both BJ venoms in SiHa cell promoted nuclear condensation, fragmentation, and formation of apoptotic bodies by DAPI assay, mitochondrial damage by Rhodamine-123, and cell cycle block in the G1-G0 phase. BJ and BE venoms present anticancer potential, suggesting that both Bothrops venoms could be used as prototypes for the development of new therapies.

Green Tea Catechin Metabolites Exert Immunoregulatory Effects on CD4(+) T Cell and Natural Killer Cell Activities

Tea catechins, such as (-)-epigallocatechin-3-O-gallate (EGCG), have been shown to effectively enhance immune activity and prevent cancer, although the underlying mechanism is unclear. Green tea catechins are instead converted to catechin metabolites in the intestine. Here, we show that these green tea catechin metabolites enhance CD4(+) T cell activity as well as natural killer (NK) cell activity. Our data suggest that the absence of a 4'-hydroxyl on this phenyl group (B ring) is important for the effect on immune activity. In particular, 5-(3',5'-dihydroxyphenyl)-γ-valerolactone (EGC-M5), a major metabolite of EGCG, not only increased the activity of CD4(+) T cells but also enhanced the cytotoxic activity of NK cells in vivo. These data suggest that EGC-M5 might show immunostimulatory activity.