Butyrate-mediated Resistance to Trichostatin A Accompanied by Elevated Expression of Glucose Transporter 3 (GLUT3) in Human Colorectal Carcinoma HCT116 Cells.

OBJECTIVE: The aim of study was to investigate the correlation of GLUT3 upregulation and butyrate-mediated acquired chemoresistance. METHOD: A butyrate-resistant CRC cell model was established from parental (PT) HCT116 cells by gradually increasing the concentration of sodium butyrate (NaBu), followed by evaluation of resistance to butyrate and trichostatin A (TSA) by the MTT method. The expression of SLC2A3 gene and GLUT3 protein were assessed by semi-quantitative RT-PCR and western blotting, respectively. The correlation of GLUT3 and butyrate-induced acquired chemoresistance was investigated using SLC2A3 silencing. RESULTS: Butyrate-resistant (BR) HCT116 cells were more tolerant to butyrate-induced cell death and also resist to 750 and 1000 nM TSA when compared with HCT116-PT cells (p <0.05). Long-term exposure to butyrate revealed that upregulation of the SLC2A3 gene was significantly increased by more than 20 fold (p < 0.01), and that of GLUT3 was elevated by approximately 2 fold (p < 0.05) in HCT116-BR cells. Silencing of the SLC2A3 gene increased the sensitivity of HCT116-BR cells to the effects of TSA. CONCLUSION: Upregulation of GLUT3 is associated with resistance to butyrate and TSA. GLUT3 is a molecular target for the detection of chemoresistant CRC cells and thus a potential target for diagnostic strategies.

Effects of Pogonatherum paniceum (Lamk) Hack extract on anti-mitochondrial DNA mediated inflammation by attenuating Tlr9 expression in LPS-induced macrophages.

BACKGROUND/OBJECTIVES: Mitochondrial DNA leakage leads to inflammatory responses via endosome activation. This study aims to evaluate whether the perennial grass water extract (Pogonatherum panicum) ameliorate mitochondrial DNA (mtDNA) leakage. MATERIALS/METHODS: The major bioactive constituents of P. paniceum (PPW) were investigated by high-performance liquid chromatography, after which their antioxidant activities were assessed. In addition, RAW 264.7 macrophages were stimulated with lipopolysaccharide, resulting in mitochondrial damage. Quantitative polymerase chain reaction and enzyme-linked immunosorbent assay were used to examine the gene expression and cytokines. RESULTS: Our results showed that PPW extract-treated activated cells significantly decrease reactive oxygen species and nitric oxide levels by reducing the p22phox and iNOS expression and lowering cytokine-encoding genes, including IL-6, TNF-α, IL-1ß, PG-E2 and IFN-γ relative to the lipopolysaccharide (LPS)-activated macrophages. Furthermore, we observed that LPS enhanced the mtDNA leaked into the cytoplasm, increasing the transcription of Tlr9 and signaling both MyD88/Irf7-dependent interferon and MyD88/NF-κb p65-dependent inflammatory cytokine mRNA expression but which was alleviated in the presence of PPW extract. CONCLUSIONS: Our data show that PPW extract has antioxidant and anti-inflammatory activities by facilitating mtDNA leakage and lowering the Tlr9 expression and signaling activation.

Microarray Analysis of Gene Expression Involved in Butyrate-Resistant Colorectal Carcinoma HCT116 Cells.

BACKGROUND: Resistance to chemotherapeutic agents is usually found in cancer stem cells (CSCs) and cancer stem-like cells that are often regarded as the target for cancer monitoring. However, the different patterns of their transcriptomic profiling is still unclear. OBJECTIVE: This study aims to illustrate the transcriptomic profile of CSCs and butyrate-resistant colorectal carcinoma cells (BR-CRCs), by comparing them with parental colorectal cancer (CRC) cells in order to identify distinguishing transcription patterns of the CSCs and BR-CRCs. METHODS: Parental CRC cells HCT116 (HCT116-PT) were cultured and induced to establish the butyrate resistant cell model (HCT116-BR). Commercial enriching of the HCT116-CSCs were grown in a tumorsphere suspension culture, which was followed firstly by the assessment of butyrate tolerance using MTT and PrestoBlue. Then their gene expression profiling was analyzed by microarray. RESULTS: The results showed that both butyrate-resistant HCT116 cells (HCT116-BR) and HCT116-CSCs were more tolerant a butyrate effects than HCT116-PT cells. Differentially expressed gene profiles exhibited that IFI27, FOXQ1, PRF1, and SLC2A3 genes were increasingly expressed in CSCs, and were dramatically overexpressed in HCT116-BR cells when compared with HCT116-PT cells. Moreover, PKIB and LOC399959 were downregulated both in HCT116-CSCs and HCT116-BR cells. CONCLUSION: Our findings shed light on the transcriptomic profiles of chemoresistant CRC cells. This data should be useful for further study to provide guidelines for clinical prognosis to determine the guidelines for CRC treatment, especially in patients with chemoresistance and designing novel anti-neoplastic agents.