Iron Chelation Properties of Green Tea Epigallocatechin-3-Gallate (EGCG) in Colorectal Cancer Cells: Analysis on Tfr/Fth Regulations and Molecular Docking.

In many studies, green tea epigallocatechin-3-gallate (EGCG) has already shown its therapeutic effects in colorectal cancer cells (CRC). However, its mechanism of actions in CRC is poorly elucidated. Hence, this study attempts to elucidate the mechanism of actions of green tea ECGG via iron chelation activity in CRC. In order to investigate this property, HT-29 cell lines (CRC) were treated with EGCG for 24 h, 48 h, and 72 h. From western blot analysis, EGCG had upregulated transferrin receptor (TfR) protein and downregulated Ferritin-H (FtH) protein indicating that iron chelation activity has occurred in CRC. Meanwhile, the molecular docking study demonstrated that EGCG is able to strongly interact the ferritin protein with a high binding affinity (-7.3 kcal/mol) via strong hydrogen bindings to glutamic acid 64 and lysine 71; two moderate hydrogen bindings to asparagine 74 and a hydrophobic interaction to the hydrophobic pocket of lysine 71. The strong interaction predicted between EGCG to ferritin may lead to inhibition of ferritin by EGCG, thus supporting the downregulation of FtH observed in in vitro studies. Molecular docking study of TfR to EGCG cannot be modulated based on the in vitro results. In conclusion, EGCG possesses iron chelator property in CRC and this potential could be further exploited for CRC treatment.

Induction of Endoplasmic Reticulum Stress Pathway by Green Tea Epigallocatechin-3-Gallate (EGCG) in Colorectal Cancer Cells: Activation of PERK/p-eIF2α/ATF4 and IRE1α.

Epigallocatechin-3-gallate (EGCG) is the most abundant bioactive polyphenolic compound among the green tea constituents and has been identified as a potential anticancer agent in colorectal cancer (CRC) studies. This study was aimed to determine the mechanism of actions of EGCG when targeting the endoplasmic reticulum (ER) stress pathway in CRC. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay was performed on HT-29 cell line and normal cell line (3T3) to determine the EGCG toxicity. Next, western blot was done to observe the expression of the related proteins for the ER stress pathway. The Caspase 3/7 assay was performed to determine the apoptosis induced by EGCG. The results demonstrated that EGCG treatment was toxic to the HT-29 cell line. EGCG induced ER stress in HT-29 by upregulating immunoglobulin-binding (BiP), PKR-like endoplasmic reticulum kinase (PERK), phosphorylation of eukaryotic initiation factor 2 alpha subunit (eIF2α), activating transcription 4 (ATF4), and inositol-requiring kinase 1 alpha (IRE1α). Apoptosis was induced in HT-29 cells after the EGCG treatment, as shown by the Caspase 3/7 activity. This study indicates that green tea EGCG has the potential to inhibit colorectal cancer cells through the induction of ER stress.

Dicranopteris linearis extract inhibits the proliferation of human breast cancer cell line (MDA-MB-231) via induction of S-phase arrest and apoptosis.

CONTEXT: Dicranopteris linearis (Burm.f.) Underw. (Gleicheniaceae) has been scientifically proven to exert various pharmacological activities. Nevertheless, its anti-proliferative potential has not been extensively investigated. OBJECTIVE: To investigate the anti-proliferative potential of D. linearis leaves and determine possible mechanistic pathways. MATERIALS AND METHODS: MTT assay was used to determine the cytotoxic effects of D. linearis methanol (MEDL) and petroleum ether (PEEDL) extracts at concentrations of 100, 50, 25, 12.5, 6.25 and 3.125 µg/mL against a panel of cancer cell lines (breast [MCF-7 and MDA-MB-231], cervical [HeLa], colon [HT-29], hepatocellular [HepG2] and lung [A549]), as compared to negative (untreated) and positive [5-fluorouracil (5-FU)-treated] control groups. Mouse fibroblast cells (3T3) were used as normal cells. The mode of cell death was examined using morphological analysis via acridine orange (AO) and propidium iodide (PI) double staining. Cell cycle arrest was determined using flow cytometer, followed by annexin V-PI apoptosis detection kit. RESULTS: MEDL demonstrated the most significant growth inhibition against MDA-MB-231 cells (IC50 22.4 µg/mL). PEEDL showed no cytotoxic effect. Induction of apoptosis by MEDL was evidenced via morphological analysis and acridine orange propidium iodide staining. MEDL could induce S phase cell cycle arrest after 72 h of incubation. Early apoptosis induction in MDA-MB-231 cells was confirmed by annexin V-FITC and PI staining. Significant increase in apoptotic cells were detected after 24 h of treatment with 15.07% cells underwent apoptosis, and the amount escalated to 18.24% with prolonged 48 h incubation. CONCLUSIONS: MEDL has potential as a potent cytotoxic agent against MDA-MB-231 adenocarcinoma.

Anticarcinogenic activity of Muntingia calabura leaves methanol extract against the azoxymethane-induced colon cancer in rats involved modulation of the colonic antioxidant system partly by flavonoids.

CONTEXT: Leaves of Muntingia calabura (Elaeocarpaceae) are widely used in traditional medical practice; scientific findings show various pharmacological activities. However, its anticancer effect has not been investigated thoroughly yet. OBJECTIVE: The objective of this study is to study the chemoprevention effects of MEMCL against azoxymethane (AOM)-induced colon cancer and to examine the involvement of endogenous antioxidants Materials and methods: Male Sprague-Dawley rats, divided into five groups (n = 7), were injected intraperitoneally once weekly for 2 weeks with 15 mg/kg AOM, except for the normal group (received saline). The animals were then administered orally for 8 weeks with 8% Tween-80 (vehicle; normal group), 8% Tween-80 (vehicle; cancer group) or, 50, 250 or 500 mg/kg MEMC. After treatments, colon samples were collected from each rat for the histopathological analysis, quantification of aberrant crypt foci formed and determination of colon antioxidant levels. MEMC was also subjected to HPLC analysis. RESULTS: The extract exerted significant (p < 0.05): (i) anti-carcinogenesis activity, indicated by a decrease in the total aberrant crypt formation; (ii) antioxidant activity by increasing the colon tissue antioxidant markers [i.e., superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH)] and reducing the oxidant marker (i.e., malonaldehyde (MDA) levels in comparison with the cancer group. HPLC analysis demonstrated the presence of rutin. DISCUSSION AND CONCLUSIONS: Muntingia calabura leaves exert anticancer effect against AOM-induced colon cancer possibly via the action of flavonoids on the colon tissue antioxidant activity.

Channa striatus cream down-regulates tumour necrosis factor (TNF)-alpha gene expression and alleviates chronic-like dermatitis in mouse model.

ETHNOPHARMACOLOGICAL RELEVANCE: Haruan, Channa striatus, is a freshwater fish which has been well-known locally to accelerate wound healing during post-operative and post-partum periods. The fish extract also has potent anti-inflammatory and analgesic properties. AIM OF THE STUDY: To assess topical anti-inflammatory effect of Haruan cream on 12-0-tetradecanoylphorbol-13-acetate (TPA)-induced chronic-like dermatitis in mice. MATERIALS AND METHODS: Male ICR mice were randomized into six groups of five mice each: acetone (vehicle), TPA alone (negative control), three Haruan treatment groups (Haruan 1%, Haruan 5% and Haruan 10%) and hydrocortisone 1% (positive control). Briefly, both surfaces of mouse ears were applied with TPA (2.5µg/20µl acetone) for five times on alternate days and with Haruan or hydrocortisone 1% cream for the last three days. Mouse ear thickness was measured 24h after final treatment with the cream and the ears were harvested for further histological analysis and gene expression studies of TNF-α by real-time reverse transcriptase-polymerase chain reaction (RT-qPCR). RESULTS: Topical application of Haruan cream had reduced the mouse ear thickness 18.1-28%) with comparable effect to the positive control. In addition, histopathological comparison had shown evident reduction in various parameters of cutaneous inflammation including dermal oedema, inflammatory cells infiltration and proliferation of epidermal keratinocytes. Furthermore, TPA application had resulted in the up-regulation of TNF-α gene expression by 353-fold, which was subsequently down-regulated by the Haruan cream (34- to 112-fold). CONCLUSION: Haruan is an effective topical anti-inflammatory agent in this mouse model of chronic-like dermatitis, thus suggesting its potential as a non-steroidal treatment option for chronic inflammatory dermatoses.

Synthesis and evaluation of indole-containing 3,5-diarylisoxazoles as potential pro-apoptotic antitumour agents.

A series of novel indole-containing diarylisoxazoles has been synthesised, based on our previous work on the synthesis and pro-apoptotic antitumour activity of indole-based diaryl 1,2,4-oxadiazoles. Concise synthetic routes to both 3-(indol-2-yl)-5-phenylisoxazoles and 5-(indol-2-yl)-3-phenylisoxazoles have been developed with full regiochemical control, bearing substituents on the indole ring, indole nitrogen, and/or phenyl group. Additionally a series of the related 5-(1H-indol-5-yl)-3-phenylisoxazoles has been prepared. In vitro evaluation in human cancer cell lines Colo320 (colon) and Calu-3 (lung) revealed preferential antiproliferative activity within the 5-(indol-5-yl)-3-phenylisoxazole series (low micromolar IC(50)). Further analysis revealed the ability of the indol-5-yl series to induce expression of effector caspases-3 and -7, and retention of viability of the human bronchial smooth muscle cell (BSMC) control cell population (particularly for compounds 18c and 18e).