Study On Relationship Between CUEDC2 Expression And Sensitivity To Cisplatin Of Ovarian Serous Carcinoma

Background:Ovarian cancer is one of the common gynecological malignancies in the world.According to WHO classification of oncology,ovarian cancer,including serous carcinoma,endometrial carcinoma,clear cell carcinoma,mucinous carcinoma and malignant Brenner tumor Type,is a group of tumors with different molecular biological characteristics and histomorphology in which serous cancer accounted for about 75%.With mortality higher than the sum of cervical cancer and endometrial cancer,the ovarian cancer's 5-year survival rate is only about 30%,ranking first in gynecological malignancies.150,000 ovarian cancer patients have died around the world annually,while the number of ovarian cancer deaths of China mainland reached 23,000 in 2015.This is due to the ovarian cancer found uneasy,that 70%of ovarian cancer patients is the late stage of the tumor after initial diagnosis;and because of ovarian cancer late chemotherapy resistance problems,the long-term efficacy and survival rate of ovarian cancer patients greatly reduced.CUEDC(CUE domain-containing protein 2)is a multifunctional protein consisting of 287 amino acid residues,which contains a CUE domain consisting of 40 amino acid residues.Recently,according to many studies,CUEDC2 is expressed abnormally in many solid tumors,such as breast cancer,lung cancer and colon cancer.It is closely related to the occurrence and development of cancer as well as the sensitivity of drug therapy.Regulated by regulating NF-?B signaling pathway,CUEDC2 expression decrease the level of imatinib resistance in chronic myeloid leukemia cells.Previous collaborative study found that CUEDC2 can downregulate the ubiquitination level of PR and ER in human breast cancer cells and negatively regulate the estrogen and progesterone related signaling pathways,leading to the endocrine therapy tolerance of breast cancer.Mitogen activated protein kinase(MAPK)is a kind of serine or threonine protein kinase which is widely existed in mammalian cells.It is closely correlated to cell proliferation and apoptosis.The MAPK family includes many subfamilies,such as p38MAPK,c-Jun N-terminal kinase(JNK)and extracellular signal regulated kinase(ERK).MAPK signaling pathway plays an important role in the proliferation,apoptosis and chemoresistance in a variety of malignant tumors,including ovarian cancer,etc.A number of studies have shown that ovarian cancer cells can increase the sensitivity of cisplatin drugs by regulating the activity of MAPK signaling pathway.Objective:Our study want to investigate in the clinical and in vitro(Ovarian cancer cell lines SKOV3)by immunohistochemistry,Western blot,MTS and siRNA interference techniques to explore the relationship between CUEDC2 and cisplatin resistance and reveal the molecular mechanism of the interaction between CUEDC2 and MAPK signaling pathway-related factors p38MAPK,ERK.It can provide new ideas for molecular mechanisms of drug resistance in ovarian cancer,in order to find theoretical basis and neo-treatments.Methods:The topic is divided into two parts.Firstly,the expression of CUEDC2 in drug-resistant and non-drug-resistant tissues was compared by immunohistochemistry,and then the ovarian cancer SKOV3 cells were cultured in vitro by siRNA interference.The technique knocked down the expression of CUEDC2 transiently and detected the expression of MAPK pathway relating proteins.The first part:Collect 329 cases of ovarian serous carcinoma by tumor reductive surgery,using 2014 WHO grading system to determine the histological grade;to detect the expression of CUEDC2 in tumor tissue by EnVision two-step method.Combined with patients follow-up results,we want to analyze the relationship between CUEDC2 and ovarian serous carcinoma cisplatin resistance.The second part:Western blotting method was used to detect the knockdown effect of siRNA technology in SKOV3 cells.The expression of CUEDC2 was detected by MTS colorimetric assay and Trypan blue staining to detect the proliferation of SKOV3 cells in si-control group and si-CUEDC2 group with cisplatin.Western blotting was used to find the expression level of the knockdown effect of CUEDC2 and the expression of mitogen-activated protein kinase(MAPK),with SKOV3 cells dividing into cisplatin group(8?mol/L cisplatin),si-control group(cisplatin 8?mol/L,si-control 50nmol/L),si-CUEDC2 group(cisplatin 8?mol/L,si-CUEDC2 50nmol/L)and none treat group.Result:The first part:Finally,we have found 329 cases undergoing ovarian tumor reduction surgery in which 62 cases were completely treated with cisplatin after surgery for 6-8 cycles.51 cases of CUEDC2 were positive,with the positive rate being 82.3%.There were differences in the expression of CUEDC2 in the pathological grade(p =0.018)that higher grade has higher positive rate than the low grade ovarian serous.CUEDC2 positive patients were more likely to develop cisplatin resistance(p =0.006).The overall survival time of CUEDC2-positive patients was shorter than that of negative patients(p =0.0493),but there was no significant difference between the two.groups' disease free survival times(p =0.4574).In the second part:There was no difference in the number of SKOV3 cells between si-CUEDC2 group and si-control group without cisplatin treatment,however the number of cells in si-CUEDC2 group was significantly decreased compared with si-control group(p<0.05).The SKOV3 cells in si-CUEDC2 cells were expressed highly in Phospho-p38 and low in Phospho-ERK.Conclusion:1.The positive expression of CUEDC2 leads to increased likelihood of cisplatin resistance in ovarian serous carcinomas and results in poor overall survival time.2.CUEDC2 knockdown significantly increased the sensitivity of ovarian cancer cells to cisplatin perhaps 1 through MAPK pathway.