esculetin and Colorectal-Neoplasms

Colorectal cancer (CRC) is the most common malignant disease worldwide and thus new therapeutic approaches are needed. 5-Fluorouracil (5-FU) remains the most widely used agent to treat colorectal cancer (CRC). However, its clinical efficacy is currently limited by the development of drug resistance. Esculetin (EST), a coumarin, was found to have anti-proliferative and anti-migration activity in cancer.. This research aims to evaluated the influence and possible mechanism of EST on the proliferation, migration and epithelial-mesenchymal transition of CRC cell lines.. Human CRC cell lines HT-29, SW480, HCT-116, and Caco-2 were treated with various concentrations of EST (0.2, 2, 20, 200, 2000 μg/ml) or 5-FU (0.1, 1, 10, 100, 1000 μg/ml) for 48 h, and cell viability was determined by the MTT and CCK-8 assay. The motility of HCT-116 cells was detected by scratch assay. Western blot was applied to detect the protein expression. Besides, levels of Wnt3a and VEGF in HCT-116 cell culture medium supernatant were analyzed by ELISA. The anti-tumor effect was detected with HCT-116 subcutaneous tumor bearing tumor model by monitoring the tumor vomume in vivo. Finally, the tumoral expression of VEGF was measured by immunohistochemistry, and the expression of Ki67, PCNA, β-catenin, c-Myc, Cyclin D1, MMP2 and MMP7 was measured by Western blot analysis.. EST inhibited HCT-116 cell proliferation in a dose-dependent manner. Western blot analysis revealed that EST decreased the expression of Ki67, PCNA, N-cadherin, E-cadherin, vimentin, fibronectin, β-catenin, c-Myc, Cyclin D1, MMP2 and MMP7. Furthermore, EST reduced the release of Wnt3a and VEGF into HCT-116 cells culture medium. After EST treatment, the tumor volume was significant smaller than that of the control group, and the tumoral levels of VEGF were decreased. Moreover, western blot analysis indicated that the expression of Ki67, PCNA, β-catenin, c-Myc, Cyclin D1, MMP2 and MMP7 were also significantly decreased after treated with EST. In addition, in vitro and in vivo anti-tumor results demonstrated that EST combined with 5-FU could increase the inhibitory effect of 5-FU on HCT-116 cells proliferation, migration and epithelial-mesenchymal transition.. EST enhances the inhibitory effect of 5-FU on the proliferation, migration and epithelial-mesenchymal transition of CRC.

Topics: Animals; Antimetabolites, Antineoplastic; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Colorectal Neoplasms; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Epithelial-Mesenchymal Transition; Fluorouracil; Humans; Mice; Survival Analysis; Umbelliferones; Wnt Signaling Pathway; Xenograft Model Antitumor Assays

Colorectal cancer (CRC) is the most common malignant disease worldwide due to its metastasis via the epithelial-mesenchymal transition (EMT) process. E-cadherin and Wnt signaling are emerging as potential targets for suppressing the EMT. In this context, Axin2 has been recognized as a negative regulator that inhibits glycogen synthase kinase 3β (GSK3β)-mediated degradation of Snail1, a transcriptional repressor of E-cadherin. However, Axin2 can also impede Wnt signaling via β-catenin degradation. Therefore, Axin2 may serve as either a promoter or suppressor of tumors, and the effects of its inhibition on the cell proliferation and metastasis of CRC require further elucidation. Here, esculetin (ES), a coumarin, was found to have the most potential effects on both β-catenin-responsive transcriptional and E-cadherin promoter activities. ES also showed anti-proliferative and anti-invasive activities in CRC cells. Mechanistically, Axin2 suppression by ES contributed to E-cadherin-mediated Wnt signaling inhibition. Moreover, the ability of ES to inhibit tumor growth and metastasis via Axin2 suppression was further supported in an HCT116-implanted orthotopic mouse model. Collectively, these findings suggest that targeting the Axin2/E-cadherin axis by ES may be an attractive therapeutic strategy for the treatment of metastatic CRC.

Topics: Animals; Antineoplastic Agents; Axin Protein; Cadherins; Cell Line, Tumor; Colorectal Neoplasms; Gene Expression Regulation; Humans; Male; Mice; Mice, Nude; Neoplasms, Experimental; Snail Family Transcription Factors; Umbelliferones; Up-Regulation

Colorectal cancer has become more common in many regions of the world. Recently, we showed that esculetin, a natural coumarin, induces apoptosis in HT-29 colon cancer cells via the reactive oxygen species-mediated mitochondrial pathway. The present study examined whether esculetin induces apoptosis in HT-29 colon cancer cells by inducing endoplasmic reticulum (ER) stress. We found that esculetin induced characteristic signs of ER stress, confirmed by ER staining, mitochondrial calcium overload and expression of ER stress-related proteins (i.e. glucose regulated protein 78, phosphorylated ribonucleic acid-dependent protein kinase-like ER kinase, phosphorylated inositol requiring enzyme 1, phosphorylated eukaryotic initiation factor-2α, spliced X-box binding protein 1 and cleaved activating transcription factor 6). Esculetin also induced the expression of the CCAAT/enhancer-binding protein-homologous protein (CHOP) and pro-apoptotic factors caspase-12. Moreover, transfection of colon cancer cells with a small interfering ribonucleic acid targeting CHOP attenuated esculetin-induced apoptosis. Taken together, these results suggest that the ER stress response plays an important role in esculetin-induced apoptosis in human colon cancer cells.

Topics: Apoptosis; Colorectal Neoplasms; Endoplasmic Reticulum Stress; Free Radical Scavengers; HT29 Cells; Humans; Transcription Factor CHOP; Umbelliferones