The Expression Of Pin1 Protein In Esophageal Cancer

Protein phosphorylation on certain serine or threonine residues preceding proline (Ser/Thr-Pro) is a pivitol signaling mechanism in diverse cellular processes and its deregulation can lead to human disease. Pin1 is a highly conserved enzyme that isomerizes only the phosphorylated Ser/Thr-Pro bonds in certain proteins, thereby inducing conformational changes. Recent results indicate that such conformational changes following phosphorylation are a novel signaling mechanism pivotal in regulating many cellular functions. Peptidyl-prolyl isomerase Pin1 is an essential protein in regulating cell entry into mitosis by catalyzing the conformational change of many critical proteins. So far, more than 20 Pin1 targets have been isolated, such as cdc25, Weel, Mytl, cdc27, cyclin D1 andβ-catenin, suggesting that Pin1 might play an important role in the cell cycle regulation, signal transduction and human disease. Overexpression of Pin1 is prevalently found in human cancers, whereas its inhibition induces apoptosis and contributes to the neuronal death in Alzheimer's disease,In this study, we constructed Pin1 expression vector: pET42a+ /Pin1 and pET28b+ /Pin1, the recombinant Pin1 protein was succeed to overexpress and purified. After analyzed by CD spectrum, Pin1 protein was used to immunize mice, and the high titer of polyclonal antiserum was obtained. The Pin1 antiserum was used to detect the differential expression level of Pin1 protein in esophageal cancer specimans and normal esophageal tissue by immunohistochemical staining.Real-time quantitative PCR was also applied to detect the mRNA differential expression level in esophageal cancer tissues and normal esophageal tissue.The results reveals: at the protein level, Pin1 protein is overexpressed in esophageal cancer. On the other hand, the expression level of Pin1 mRNA in the esophageal cancer tissue has no significant change compared with the normal tissue. It demonstrated that the Pin1 expression in esophageal cancer might be regulated by translation mechanism. Our data implicate Pin1 as a valuable molecular marker for human cancer.