esculetin and Colonic-Neoplasms

We investigated the anti-cancer effects of ESC in human colon cancer LoVo cells. Cell counting assay results showed that ESC inhibited the proliferation of LoVo cells. Cell cycle arrest results showed that cell cycle was arrested during the G0/G1 phase in the ESC-treated LoVo cells. Western blot results showed that the cell cycle inhibitory proteins p53, p27, and p21 were increased, and cyclin D1, the cell cycle progressive protein, was decreased. Sp1 is a transcription factor regulating cell proliferation, was decreased in the ESC-treated LoVo cells. Annexin V/propidium iodide staining results showed that ESC induces apoptosis in LoVo cells. Western blot results showed that Bax, cleaved caspase -3, -7, -9, and poly(ADP-ribose) polymerase, which are proapoptotic proteins, were increased and the antiapoptotic protein Bcl-2 was decreased. Taken together, ESC induced apoptosis and has an anti-cancer effect in LoVo cells.

Topics: Apoptosis; Caspase 3; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Colonic Neoplasms; Cyclin D1; Humans; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Umbelliferones

Targeting tumor metabolism by natural products is a novel approach and provides rationale for anti-cancer drug discovery. The present study aims to explore the impact of morin and/or esculetin on c-myc induced energy metabolism in 1,2-dimethylhydrazine (DMH) induced colon cancer in rats. In order to achieve this aim we analyzed the expression of glucose and glutamine transporters and the key enzymes of glycolytic pathway besides the markers of neoplastic changes viz., mucin depleted foci (MDF), beta catenin accumulated crypts (BCAC), and markers of cell proliferation viz., proliferating cell nuclear antigen (PCNA), argyrophilic nucleolar antigen (AgNOR), c-myc, c-jun and c-fos. All the parameters tested in the present study are highly influenced by the phytochemicals morin and/or esculetin in a way to prevent colon carcinogenesis. Morin and/or esculetin supplementation effectively targets tumor metabolism via β-cateinin/c-myc signaling and affects glycolysis and glutaminolysis to abrogate colon cancer in rats. The anti-cancer effect of morin is more pronounced than esculetin. The effect obtained through the combined treatment of morin and esculetin is comparable to that of individual supplementation of morin and there is no synergistic effect. Overall individual supplementation of morin scores well as a potential anticancer agent targeting glycolysis and glutaminolysis in colon cancer.

Topics: 1,2-Dimethylhydrazine; Animals; Anticarcinogenic Agents; beta Catenin; Body Weight; Carcinogenesis; Cell Proliferation; Colon; Colonic Neoplasms; Energy Metabolism; Flavonoids; Glycolysis; Male; Proto-Oncogene Proteins c-myc; Rats; Rats, Wistar; Signal Transduction; Survival Rate; Tumor Burden; Umbelliferones

The present study investigated the apoptotic effects of esculetin, a coumarin derivative, on the human colon cancer cell line HT-29. Esculetin had cytotoxic effects on HT-29 cells in a dose- and time-dependent manner; treatment with 55 μg/mL esculetin reduced cell viability by 50%. Esculetin induced apoptosis, as evidenced by apoptotic body formation, an increased percentage of cells in sub-G1 phase, and DNA fragmentation. Moreover, esculetin increased mitochondrial membrane depolarization, released cytochrome c into cytosol, and modulated the expression of apoptosis-associated proteins, resulting in reduced expression of B cell lymphoma-2, increased expression of Bcl-2-associated X protein, and activation of caspase-9 and caspase-3. Esculetin induced the formation of reactive oxygen species; however, treatment with an antioxidant reduced the apoptotic cell death induced by esculetin treatment. In addition, esculetin activated mitogen-activated protein kinases and specific inhibitors of these kinases abrogated the reduction in cell viability induced by esculetin treatment.

Topics: Antineoplastic Agents; Apoptosis; Caspase 3; Caspase 9; Colonic Neoplasms; DNA Fragmentation; HT29 Cells; Humans; Membrane Potential, Mitochondrial; Mitochondria; Mitogen-Activated Protein Kinases; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Umbelliferones

The Wnt pathway is a promising therapeutic and preventive target in various human cancers. The transcriptional complex of β-catenin-T-cell factor (Tcf), a key mediator of canonical Wnt signaling, has been implicated in human colon cancer development. Current treatment of colon cancer depends on traditional cytotoxic agents with limited effects. Therefore, the identification of natural compounds that can disrupt the β-catenin-TcF complex to suppress cancer cell growth with fewer adverse side effects is needed. To identify compounds that inhibit the association between β-catenin and Tcf, we used computer docking to screen a natural compound library. Esculetin, also known as 6,7-dihydroxycoumarin, is a derivative of coumarin and was identified as a potential small-molecule inhibitor of the Wnt-β-catenin pathway. We then evaluated the effect of esculetin on the growth of various human colon cancer cell lines and its effect on Wnt-β-catenin signaling in cells and in an embryonic model. Esculetin disrupted the formation of the β-catenin-Tcf complex through direct binding with the Lys312, Gly307, Lys345, and Asn387 residues of β-catenin in colon cancer cells. In addition, esculetin effectively decreased viability and inhibited anchorage-independent growth of colon cancer cells. Esculetin potently antagonized the cellular effects of β-catenin-dependent activity, and in vivo treatment with esculetin suppressed tumor growth in a colon cancer xenograft mouse model. Our data indicate that the interaction between esculetin and β-catenin inhibits the formation of the β-catenin-Tcf complex, which could contribute to esculetin's positive therapeutic and preventive effects against colon carcinogenesis.

Topics: Animals; Antioxidants; Apoptosis; beta Catenin; Blotting, Western; Cell Proliferation; Colonic Neoplasms; Embryo, Nonmammalian; Female; Gene Expression Regulation, Neoplastic; Humans; Immunoprecipitation; Luciferases; Mice; Mice, Nude; Models, Molecular; Protein Conformation; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Tumor Cells, Cultured; Umbelliferones; Xenograft Model Antitumor Assays; Xenopus laevis

Esculetin, a phenolic compound, has been shown to inhibit the growth of colon tumors in animal studies. However, the roles of signaling pathways and cell cycle regulation in the esculetin-induced inhibition of cancer cell growth, remain to be elucidated. The present study suggests a novel mechanism for the Ras/ERK1/2 pathway in esculetin-treated human colon cancer HCT116 cells. The treatment of cells with esculetin resulted in significant growth inhibition and G1 phase cell cycle arrest, which led to the down-regulation of cyclin and cyclin-dependent kinase (CDK) expressions. This G1 phase cell cycle arrest was associated with the up-regulation of p27KIP expression. In addition, ERK1/2 was activated by esculetin. The pre-treatment of cells with the MEK1/2-specific inhibitor, PD98059, blocked the p27KIP expression induced by esculetin. Blockage of the ERK1/2 function consistently prevented the inhibition of cell proliferation and decreased G1 phase cell cycle protein levels. Furthermore, Ras activation was increased by the esculetin treatment. Transient transfection of the dominant negative Ras (RasN17) mutant gene abolished both the ERK1/2 activity and p27KIP expression induced by esculetin. Finally, the overexpression of RasN17 suppressed the esculetin-induced reduction in cell proliferation and cell cycle proteins. In conclusion, these results indicate that the Ras/ERK1/2 pathway is mediated by the p27KIP1 induction, leading to a reduction in cyclin/CDK complexes in the esculetin-induced inhibition of colon cancer cell growth. Overall, these findings indicate that the molecular action of esculetin has therapeutic potential for the treatment of colon malignancies.

Topics: Antineoplastic Agents; Cell Cycle; Cell Proliferation; Cell Separation; Colonic Neoplasms; Cyclin-Dependent Kinase Inhibitor p27; Flow Cytometry; Genes, ras; HCT116 Cells; Humans; Immunoprecipitation; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; ras Proteins; Transfection; Umbelliferones

The effects of esculetin (6,7-dihydroxycoumarin) and its 6-glycoside, esculin, on 8-oxo-2'-deoxyguanosine (8-oxodG) formation and carcinogenesis induced by a chemical carcinogen, 1,2-dimethylhydrazine (DMH), were examined in the colons of male Fischer 344 rats. Animals were given water containing esculetin or esculin for 7 d before subcutaneous injection of DMH (20 mg/kg body wt), killed 24 h after DMH treatment, and the levels of thiobarbituric acid reactive substances (TBARS) and 8-oxodG in the colons were determined. Both esculetin and esculin suppressed significantly the DMH-induced increases in 8-oxodG and TBARS in rat colon mucosa. We further investigated the modifying effect of esculin intake on the development of DMH-induced colonic aberrant crypt foci (ACF). Animals were given DMH once a week for 4 weeks to induce ACF. They then received water containing esculin ad libitum for 5 weeks (initiation phase) or 11 weeks after DMH treatment (post-initiation phase). Animals in the positive control group received tap water throughout the experiment. At the end of the experiment (16 weeks), the ingestion of esculin during the initiation phase significantly reduced the incidence of gross tumors, the number of ACF per rat and the mean number of AC per focus, while the esculin treatment during the post-initiation phase significantly decreased only the number of ACF per rat. These results suggest that esculin intake has an inhibitory effect on DMH-induced oxidative DNA damage and carcinogenesis in rat colons.

Topics: 1,2-Dimethylhydrazine; 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Carcinogens; Colonic Neoplasms; Deoxyguanosine; DNA Damage; Esculin; Intestinal Mucosa; Male; Oxidation-Reduction; Random Allocation; Rats; Rats, Inbred F344; Thiobarbituric Acid Reactive Substances; Umbelliferones