Study On Colorectal Cancer Related Proteins

Part I The influence of PCBP1on oxaliplatin susceptibility in colorectal caner cellsObjective The aim of the project is to investigate the relationship between PCBP1expression and oxaliplatin susceptibility, and provide a new biomarker for oxaliplatin-based chemotherapy resistance in colorectal cancer.Method (1) Using lipofectamine2000to transfect PCBP1-siRNA into HT-29/L-OHP cells, western blot and quantitative PCR detected silencing effect.(2) CCK8detected PCBP1silencing HT-29/L-OHP cell drug sentivity.(3) We used PCBPl-siRNA to silence PCBP1in HT-29which had more PCBP1expression. CCK8detected PCBP1silencing HT-29cell IC50value.(4) We used a PCBP1overexpression plasmid to upregulate PCBP1in HCT116cells. Then measured the effect of PCBP1upregulation on IC50value.Result (1) PCBP1-siRNA (Sense:GAGUGUGUCAAGCAGAUUUTT; Antisens: AAAUCUGCUUGACACACUCTT) group was the most interference efficient siRNA group. The expression of PCBP1protein was reduced (74.33±1.52)%and the expression of PCBP1mRNA was (58.77±0.48)%with the most silencing effect.(2) The IC50value for oxaliplatin in HT-29/L-OHP cells was (26.57±1.25) ug/ml; PCBP1siRNA interference significantly increased oxaliplatin sensitivity in HT-29/L-OHP cell line and was accompanied by a considerable decrease in the IC50value to (16.93±0.96) ug/ml (t=55.56, p<0.01).(3) HT-29had higher level of PCBP1expression than HCT-116cells.(4) PCBP1siRNA interference significantly increased oxaliplatin sensitivity in HT-29cell line and was accompanied by a considerable decrease in the IC50values form (3.80±0.53) ug/ml to (2.53±0.42) ug/ml (t=19.52, p<0.01); PCBP1upregulation significantly attenuated oxaliplatin sensitivity in HCT-116cell line and was accompanied by a considerable increase in the IC50values form (17.45±1.36)ug/ml to (34.48±05.44)ug/ml (t=-7.65,p<0.01).Conclusion PCBP1is a potential biomarker for predicting oxaliplatin resistance in colorectal cancer cells. Part II The expression and prognostic value of interferon-induced transmembrane protein1in colorectal cancerObjective By using of paraffin wax of colorectal specimens to construct the tissue microarray, and the method of immunohistochemistry, we examined the expression level of IFITM1and assessed its prognostic value in human colorectal cancer.Method All180colorectal tissue specimens with corresponding normal epithelium tissues were obtained from colorectal patients who underwent surgical resection at Nanjing Medical University Affiliated Huainan First People’s Hospital from July2006through August2007. The correlations between IFITM1expression, the clinicopathological factors and overall survival rate were evaluated. Statistical analysis was performed through SPSS software18.0. All analyses were considered to be statistical significant when p values <0.05. The significance of differences between the immunoreactivity grades of IFITM1expression in malignant and adjacent benign tissue was determined by using the Wilcoxon rank sum test. The correlation between IFITM1expression and clinicopathological characteristics was examined by using Pearson chi-square. Survival data were evaluated by using the Kaplan-Meier method and compared by the log-rank test. Univariate and multivariate survival analysis were performed using Cox regression analysis.Result In colorectal cancer, there is no significant difference between colorectal tissue specimens and corresponding normal epithelium tissues(p=0.384). IFITM1was over-expressed in colonic adenocarcinoma (p=0.044) but not in rectal adenocarcinoma. The expression of IFITM1was significantly correlated with histological differentiation (p=0.031). Moreover, Kaplan-Meier survival analysis demonstrated that patients with higher IFITM1expression had worse overall survival outuomes than those with lower levels of IFITM1expression in rectal cancer (p=0,037). However, IFITM1expression was not a significant negative prognostic factor for survival by univariate or multivariate analyses.Conclusion In rectal cancer, the expression of IFITM1is correlated with patient’s poor prognostic. It could be used to evaluate rectal adenocarcinoma prognostic.