The Expression Of COX-2 And Mdr-related Proteins In Chemotherapy For Gastrointestinal Adenocarcinoma

Background: Gastrointestinal cancer is highly prevalent,and a leading cause of cancer death in worldwide.Adjuvant chemotherapy after surgery has been demonstrated to provide benefits on patients' survivals and significantly reduce the risk of postoperative recurrence.However the multidrug resistance(MDR)limits the application of chemotherapeutic agents for gastrointestinal adenocarcinoma.Some studies showed that COX-2 may be involved in the occurrence of multidrug resistance,but the relationship between COX-2 and MDR-related proteins during the chemotherapy is still unclear.Objective: To detect the expression of cyclooxygenase-2(COX-2),multidrug resistance associated protein 1(MRP1),and glutathione S-transferase pi(GST-?)in peripheral blood samples of the patients during pre-/postoperation and postoperative chemotherapy with gastrointestinal adenocarcinoma,investigate the relationship between the expression of COX-2 and multidrug resistant proteins(MRP1 and GST-?).Methods: Whole blood was collected from 15 patients with gastrointestinal adenocarcinoma and 15 healthy volunteers in the department of general surgery,Lanzhou University Second Hospital from June 2015 to March 2016.To assess the expression of COX-2,MRP1 and GST-?between pre-/postoperation,as well as first,third and sixth chemotherapy by means of enzyme-linked immune sorbent assay(ELISA)and reverse transcriptase polymerase chain reaction(RT-PCR),and then analyze their correlations.Results: The expression of proteins and mRNA in MRP1 and GST-? had no significant difference in pre-/postoperation group(p > 0.05).The COX-2 mRNA in postoperation group is higher than that in preoperation group(p < 0.05);however,the protein of COX-2 was no significant difference between two groups(p > 0.05).With the development of chemotherapy,the expression of proteins and m RNA in COX-2,MRP1 and GST-? were gradually increased,after the sixth course of chemotherapy,the proteins of COX-2 and MRP1,COX-2 mRNA and GST-?mRNA were significantly higher than those in the first course of chemotherapy(p < 0.05).Correlation analysis revealed the proteins of COX-2 and MRP1,GST-? and MRP1 have a positive correlation(r = 0.378;r = 0.265 p < 0.05),and this association was also found between COX-2mRNA and GST-? mRNA(r = 0.538,p = 0.006).Conclusions: With the development of chemotherapy,the expression of multidrug resistant proteins(MRP1 and GST-?)gradually increased in the peripheral blood of the patients with gastrointestinal adenocarcinoma;COX-2 may be involved in the development of drug resistance during chemotherapy after gastrointestinal adenocarcinoma resection.