ABSTRACT
To investigate the influence of longan flower extract (LFE) on the sensitization of colorectal cancer (CRC) cells to 5-fluorouracil (5-FU) treatment, HT-29, Colo 320DM and SW480 cells were treated with LFE and 5-FU alone and in combination, and the cell viability was then assessed by trypan blue exclusion, the cell cycle by propidium iodide staining, the mitochondria membrane potential by rhodamine 123 staining, and the expression levels of associated genes by immunoblotting and quantitative real-time polymerase chain reaction. LFE and 5-FU synergistically inhibited cell proliferation of HT-29 and Colo 320DM cells. Combined treatment also elevated the level of loss of mitochondria membrane potential of these two CRC cells and arrested HT-29 cells in the S phase of the cell cycle, in association with down-regulation of cyclin A mRNA expression. LFE synergistically potentiated chemosensitivity to 5-FU in at least two CRC cell lines. The results indicated that LFE has potential as a novel agent for the sensitization of CRC cells to 5-FU.
Subject(s)
Antimetabolites, Antineoplastic/pharmacology , Colorectal Neoplasms/drug therapy , Drug Synergism , Flowers/chemistry , Fluorouracil/pharmacology , Plant Extracts/pharmacology , Sapindaceae/chemistry , Apoptosis , Cell Cycle , Cell Line, Tumor , Cell Proliferation , Cell Survival , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Humans , Plant Extracts/chemistryABSTRACT
BACKGROUND: Hypoxia has been shown to facilitate tumor progression. Hypoxia-regulated microRNA-210 (miR-210) may play an important role in carcinogenesis and tumor progression. In this study, we evaluated the clinical significance of miR-210 expression in upper tract urothelial carcinoma (UTUC). METHODS: Eighty-three UTUC patients participated in this study. All of them provided cancer tissue samples and 50 of them provided non-cancerous urothelium samples. Clinicopathologic data were collected by reviewing medical records. The expression of miR-210 and hypoxia-inducible factor-1α (HIF-1α) was determined by quantitative real-time polymerase chain reaction. The relationship between clinicopathologic variables and the expression of miR-210 and HIF-1α was analyzed statistically. RESULTS: MiR-210 is overexpressed in UTUC compared to non-cancerous urothelium (p < 0.001); it is also upregulated in high-stage and high-grade tumors (p = 0.020 and 0.049, respectively). HIF-1α is overexpressed in UTUC and correlates positively with miR-210 expression (r = 0.442, p = 0.001). CONCLUSION: Both miR-210 and HIF-1α are involved in promoting UTUC carcinogenesis. MiR-210 is also correlated with tumor progression. Further studies are needed to clarify the underlying mechanism.
Subject(s)
Carcinoma, Transitional Cell/genetics , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , MicroRNAs/genetics , Neovascularization, Pathologic/genetics , Adult , Aged , Carcinogenesis/genetics , Carcinoma, Transitional Cell/pathology , Cell Hypoxia/genetics , Disease-Free Survival , Female , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , Neovascularization, Pathologic/pathology , Urothelium/pathologyABSTRACT
Sex-determining region Y (SRY)-box protein 2 (SOX2) plays a critical role in stem cell maintenance and carcinogenesis. In addition to its function as a minor-groove DNA binding transcription factor, our previous study showed that SOX2 also acts as a RNA binding protein. In current study, we first showed that SOX2 displayed high affinity toward the mRNA encoding S100A14 in BFTC905 and that depletion of SOX2 resulted in a decrease of S100A14 mRNA and protein level. To characterize the RNA binding sequence recognized by SOX2, oligomer-directed RNase H digestion was coupled to the cross-linking before immunoprecipitation assay to demonstrate that SOX2 preferentially binds to the 3'-UTR of the S100A14 mRNA. Using EGFP-S100A14 3'-UTR reporters and mobility shift assay, we identified that the binding sequence on the 3'-UTR of the S100A14 mRNA exhibits a stem-loop structure. Together, our data indicates that SOX2 enhances S100A14 expression by binding to the 3'-UTR of the S100A14 mRNA. Functionally, depletion of SOX2 increases growth and mobility of BFTC905. Knock-down of S100A14 in BFTC905 also leads to an increase in the number of the cells in the S phase and higher mobility, suggesting that SOX2 suppresses cell growth and mobility through promoting the expression of S100A14. Together, our experimental evidence indicates that SOX2 is capable of exerting its cellular functions by functioning as an RNA binding protein in post-transcriptional regulation.
ABSTRACT
Ellagic acid has been demonstrated to inhibit the growth of several types of cancer cells. However, whether it sensitizes human colorectal carcinoma cells to 5-fluorouracil, has not yet been investigated. Colorectal carcinoma HT-29, Colo 320DM, SW480 and LoVo cells were treated with ellagic acid (2.5-25 µg/ml) and 5-fluorouracil (5-25 µM) alone and in combination and then the viability was assessed by trypan blue exclusion, apoptosis by annexin-V labeling, mitochondria membrane potential by staining with rhodamine 123, and changes in the levels of proteins involved in apoptosis by immunoblotting. Ellagic acid and 5-fluorouracil synergistically inhibited cell proliferation of HT-29, Colo 320DM and SW480 cells, but cytotoxicity toward LoVo cells seems not to be potentiated by this combination. The combination also elevated apoptotic cell death of HT-29 and Colo 320DM cells. The mitochondria membrane potential was lost in combination-treated HT-29 cells, due to increased B cell lymphoma 2-associated protein X (BAX): B cell lymphoma 2 protein (BCL-2) ratio and caspase-3 activity. Ellagic acid synergistically potentiated chemosensitivity to 5-fluorouracil in at least three colorectal cancer cell lines. The results indicate that ellagic acid has potential as a novel agent sensitizing colorectal cancer cells to 5-fluorouracil.
