The Significance Of P21^Cip1、p53 And WWP1 In Keloid And Normal Skin

Background and Objective: Keloid（keloid[KD]）is a kind of dermal fibrosis disease which can cause secondary damage to skin,with characteristics of excessive deposition of collagen,invasive growth without restriction to damage edge and strongly persistent hyperplasia.In recent years,the role of ubiquitination in the formation process of many kinds of tumors are gradually revealed,including the ubiquitin specific enzymes in the regulation:E3 ubiquitin ligase.The possible mechanisms of its participation in tumor formation process are related to cell proliferation,senescence and disorganization of signaling pathways.In 2010,the Japanese scholar GWAS discovered that the NEDD4‐1 gene may play an important role in the formation of keloid.E3 ubiquitin ligase WWP1 is one of the members in NEDD4 protein family.The family also contains HECT and WW domain.Many studies have shown that WWP1 expresses abnormally in a variety of tumors.Many studies of breast cancer and prostate cancer have shown the most detailed reports of the abnormal expression of WWP1.The p53 gene is now recognized as a tumor suppressor gene,which is located on chromosome 17q13.1.The possible mechanism of its participation in tumor inhibition involves cell apoptosis and repair of DNA damage.Its action pathway is divided into direct and indirect ways.The latter actions in the way of improving the concentration of P21Cip1.P21Cip1 is a CDK inhibitory factor,which was detected in a cell cycle suppressor gene study for the first time.But the significance of its participation in apoptosis is still not clear.Keloid,as a kind of invasive growth,unrestrictive cell proliferation and limited cell apoptosis disease,is in chaos with abnormal deposition of extracellular matrix,which is supposed to be associated with the lack of control of the cell cycle gene and cytokine.This experiment detects the expression of p21^Cip1,p53 and WWP1 through immunohistochemical method（Immunohistochemistry,ICH）and RT‐PCR and compares the differences of them in keloid and normal skin tissues.The aim is to explore relationship between these factors and the formation of keloid.Materials and Methods: Selection of keloid specimens of 7 patients,aged 14⁵0 years old（30.1 ± 8.7）,male 4 cases,female 3 cases,normal skin specimens of 5 patients aged14⁵0（31.8 ± 8.4）.The specimens were divided into 2 parts,one use RT‐PCR to detect the expression of p21^Cip1,p53 and WWP1 m RNA in the tissues,while the other detect the expression of p21^Cip1,p53 and WWP1 through immunohistochemistry.Remove well‐preserved at ‐80 ℃ liquid nitrogen keloid and normal skin tissues into the TRIzol RNA homogenizer.First,extract total RNA,and detect the RNA concentration and purity by UV spectrophotometer.Next,transcript and amplify c DNA by PCR.Another part of the organization was observed and photographed under the microscope after slicing,dewaxing,adding antibody,incubation,coloring,dehydration and mounting.JEDA 801 D morphological image analysis system was used to measure the average optical density of p21^Cip1,p53 and WWP1.Results: Compared the normal group with the patient group,the P53 protein staining show that there is no positive sense in the two groups,the difference in this study is not statistically significant（P> 0.05）.The average optical density of WWP1 staining in patients group is significantly reduced,the difference is statistically significant.P21Cip1 protein is significantly increased in the patient group,and also statistically significant（P<0.05）.In subsequent RT‐PCR experiments,the expression level of m RNA was also consistent with the immunohistochemical results.Conclusions:In this study,we found that the expression of p53 in keloid was not found to be significantly different between the two groups while WWP1 an d p21^Cip1 in keloid tissues were significantly reduced.In keloid tissues,loss of f unction of p53 may not play a decisive role,and the reduction of p21^Cip1 prote in showed that p21^Cip1 protein can activate the p53 pathway and cell cycle reg ulation may play a key role in the formation of keloid.And it’s supposed that WWP1 in keloid may be suppressed by some factors,but no evidence support this point.In summary.We think that the keloid may not be directly regulated by P53 protein,while p21^Cip1 may play an inportant role in the process.The r ole of ubiquitination of WWP1 in the process of keloid fibroblasts apoptosis reg ulation may not as important as we thought.