esculetin and Mouth-Neoplasms

7,12-Dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch carcinogenesis is widely preferred to assess the tumor-inhibiting efficacy of the medicinal plants or their constituents. The present study explores the tumor-inhibiting potential of esculetin by utilizing the status of lipid peroxidation by products (thiobarbituric acid reactive substances), antioxidants (vitamin E, reduced glutathione, superoxide dismutase, catalase, and glutathione peroxidase), and phase I and phase II detoxification agents as biochemical end points and by using histopathological studies as well in DMBA-induced hamster buccal pouch carcinogenesis. Oral tumors developed in the buccal pouch were subjected to histopathological studies, and were confirmed as oral squamous cell carcinoma. Hamsters treated with DMBA alone showed an abnormal pattern of lipid peroxidation, antioxidants, and detoxification agents as compared to control hamsters. The status of the above-mentioned biochemical markers and histopathological abnormalities were found to be reversed in DMBA + esculetin-treated hamsters. The result of the present study thus indicates the tumor preventive potential of esculetin in DMBA-induced oral carcinogenesis.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Biomarkers, Tumor; Cricetinae; Lipid Peroxidation; Mouth Neoplasms; Umbelliferones

Esculetin, a coumarin compound, has anti-proliferative effects on various types of human cancer cells, but its effect on oral squamous cell carcinoma (OSCC) is unknown. In this study, we determined whether esculetin had anti-proliferative effects on two oral squamous cell lines, HN22, and HSC2. We found that esculetin inhibited cell viability by inducing apoptosis, as evinced by apoptotic cell morphologies, nuclear fragmentation, and the multi-caspase/MMP activity. Furthermore, proteomic analysis was used to identify the target-specific proteins involved in esculetin treatment. Intriguingly, apoptotic cell death by esculetin was associated with significant inhibition of the EGFR/PI3K/Akt signaling pathway. We also demonstrated that the expression of nucleophosmin (NPM) markedly decreased after esculetin treatment, and relocalization of NPM from the nucleous to the cytoplasm, together with p65, potentiated apoptotic stimulation. Additionally, our data indicated that NPM expression was markedly higher in OSCC tissues than in normal tissues. Our results collectively indicated that esculetin inhibited the proliferation of OSCC through EGFR-mediated signaling pathways and down-regulation of NPM as well as the perturbation of NPM trafficking from the nucleolus to the cytoplasm resulted in apoptosis.

Topics: Aged; Aged, 80 and over; Apoptosis; Blotting, Western; Carcinoma, Squamous Cell; Cell Line; Cell Line, Tumor; Cell Survival; Dose-Response Relationship, Drug; ErbB Receptors; Female; Humans; Immunohistochemistry; Male; Microscopy, Fluorescence; Middle Aged; Mouth Neoplasms; Nuclear Proteins; Nucleophosmin; Phosphatidylinositol 3-Kinases; Protein Transport; Proteomics; Proto-Oncogene Proteins c-akt; Signal Transduction; Umbelliferones

Esculetin (6,7-dihydroxycoumarin), a coumarin compound, is known to inhibit proliferation and induce apoptosis in several types of human cancer cells and is regarded as a promising chemotherapeutic agent. The purpose of the present study was to investigate the anti-proliferative effects of esculetin on two oral squamous cell carcinoma (OSCC) cell lines, HN22 and HSC4, through regulation of specificity protein 1 (Sp1). We examined the apoptotic effects of esculetin were measured by MTS assay, DAPI staining, Annexin V, PI staining, RT-PCR, western blot analysis and immunocytochemistry in HN22 and HSC4 cells. Taken together, the results of the present study indicate that esculetin had anti-proliferative effect on the growth of OSCC cells (HN22 and HSC4) in a dose- and time-dependent manner. The treatment of HN22 and HSC4 cells with esculetin led to a significant reduction in growth and induced apoptosis, followed by the regulation of Sp1 and Sp1 regulatory protein. This indicates that esculetin inhibited cell growth and induced apoptosis by suppressing Sp1 in HN22 and HSC4 cells, suggesting it to be a potent anticancer drug candidate for oral cancer.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Survival; Chemoprevention; Down-Regulation; G1 Phase Cell Cycle Checkpoints; Gene Expression Regulation, Neoplastic; Humans; Mouth Neoplasms; Sp1 Transcription Factor; Tumor Cells, Cultured; Umbelliferones

Esculetin has been shown to selectively induce tumor apoptosis in several types of cancers and is regarded as a promising chemotherapeutic agent. In this study, we showed that esculetin significantly suppressed the growth of oral cancer SAS cells in a dose-dependent manner. DNA content flow cytometry and TUNEL assay revealed that esculetin induced cell cycle arrest and apoptosis. Western blotting showed esculetin increased DR5 protein expression and activated caspase-8, which differed from previous studies conducted in other cell types. Furthermore, treatment with esculetin significantly increased TRAIL-induced apoptosis in SAS cells and the TRAIL-sensitizing effect was blocked by DR5/Fc chimera protein. Our results indicate that esculetin enhances TRAIL-induced apoptosis primarily through upregulation of DR5. Combination of esculetin and TRAIL may be a novel treatment strategy for oral cancers.

Topics: Antioxidants; Apoptosis; Blotting, Western; Caspase 8; Cell Cycle; Flow Cytometry; Humans; In Situ Nick-End Labeling; Mouth Neoplasms; Neoplasm Proteins; Receptors, TNF-Related Apoptosis-Inducing Ligand; Umbelliferones