RESUMO
The chromosome segregation 1like (CSE1L) protein, which regulates cellular mitosis and apoptosis, was previously found to be overexpressed in colorectal cancer (CRC) cells harboring mutations. Therefore, regulating CSE1L expression may confer chemotherapeutic effects against CRC. The gut microflora can regulate gene expression in colonic cells. In particular, metabolites produced by the gut microflora, including the shortchain fatty acid butyrate, have been shown to reduce CRC risk. Butyrates may exert antioncogenic potential in CRC cells by modulating p53 expression. The present study evaluated the association between CSE1L expression and butyrate treatment from two nontransformed colon cell lines (CCD18Co and FHC) and six CRC cell lines (LS 174T, HCT116 p53+/+, HCT116 p53/, Caco2, SW480 and SW620). Lentiviral knockdown of CSE1L and p53, reverse transcriptionquantitative PCR (CSE1L, cMyc and p53), western blotting [CSE1L, p53, cyclin (CCN) A2, CCNB2 and CCND1], wound healing assay (cell migration), flow cytometry (cell cycle analysis) and immunofluorescence staining (CSE1L and tubulin) were adopted to verify the effects of butyrate on CSE1Lexpressing CRC cells. The butyrateproducing gut bacteria Butyricicoccus pullicaecorum was administered to mice with 1,2dimethylhydrazineinduced colon tumors before the measurement of CSE1L expression. The effects of B. pullicaecorum on CSE1L expression were then assessed by immunohistochemical staining for CSE1L and p53 in tissues from CRCbearing mice. Noncancerous colon cells with the R273H p53 mutation or CRC cells haboring p53 mutations were found to exhibit significantly higher CSE1L expression levels. CSE1L knockdown in HCT116 p53/ cells resulted in G1and G2/Mphase cell cycle arrest. Furthermore, in HCT116 p53/ cells, CSE1L expression was already high at interphase, increased at prophase, peaked during metaphase before declining at cytokinesis but remained relatively high compared with that in HCT116 expressing wildtype p53. Significantly decreased expression levels of CSE1L were also observed in HCT116 p53/ cells that were treated with butyrate for 24 h. In addition, the migration of HCT116 p53/ cells was significantly decreased after CSE1L knockdown or butyrate treatment. Tumors with more intense nuclear p53 staining and weaker CSE1L staining were found in mice bearing DMH/DSSinduced CRC that were administered with B. pullicaecorum. Taken together, the results indicated that butyrate can impair CSE1Linduced tumorigenic potential. In conclusion, butyrateproducing microbes, such as B. pullicaecorum, may reverse the genetic distortion caused by p53 mutations in CRC by regulating CSE1L expression levels.
Assuntos
Butiratos , Proteína de Suscetibilidade a Apoptose Celular , Neoplasias Colorretais , Proteína Supressora de Tumor p53 , Animais , Apoptose , Butiratos/farmacologia , Células CACO-2 , Proliferação de Células , Proteína de Suscetibilidade a Apoptose Celular/genética , Segregação de Cromossomos , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Suplementos Nutricionais , Células HCT116 , Humanos , Camundongos , Mutação , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
BACKGROUND AND AIMS: Previous studies show that serum bilirubin has potent antioxidant effect and is associated with protection from kidney damage and reduce cardiovascular events. The aim of this study was to examine the association of serum total bilirubin level and mortality in uremia patients who underwent hemodialysis. METHODS: This is a nationwide retrospective long-term cohort study. Patients were registered in the Taiwan Renal Registry Data System (TWRDS) from 2005 to 2012. A total of 115,535 hemodialysis patients were surveyed and those with valid baseline total bilirubin (TB) data were enrolled. All-cause mortality was the primary outcome. RESULTS: A total of 47,650 hemodialysis patients followed for 27.6 ± 12 months, were divided into 3 groups according to different baseline serum total bilirubin levels (0.1-0.3, 0.3-0.7, 0.7-1.2 mg/dL). Mean age was 61.4 ± 13.6 years, 50% were male, 13% were hepatitis B carriers, and 20% were hepatitis C carriers. Primary outcome was the 3-year mortality. The TB level 0.7-1.2 mg/dL group had high mortality, statistically significant hazard ratio of mortality was 1.14 (crude HR, 95% 1.07-1.20, p < 0.01), and adjusted HR was 1.18 (model 1, 95% CI 1.11-1.25), 1.21 (model 2, 95% CI 1.14-1.29, p < 0.01), 1.44 (model 3, 95% CI 1.06-1.96, p < 0.01), respectively. Sensitivity test showed that after excluding 14,899 patients with hepatitis B or C, or abnormal liver function, the highest level of TB associated with higher significant mortality was still robust. CONCLUSIONS: In our study, high TB level is associated with mortality in uremia patients undergoing long-term hemodialysis, but further studies of the different effects of unconjugated or conjugated bilirubin on hemodialysis patients are needed.