The Relationship Between The Cisplatin-resistance And The Expression Of Cofilin-1 In Lung Adenocarcinoma

OBJECTIVE:To study the relationship of cofilin-1 protein on cisplatin-resistance in lung adenocarcinoma and the possible mechanism, search new target proteins for reversing cisplatin resistance.METHODS:Human lung adenocarcinoma cell strains A549 and its cisplatin-resistance cell strains A549/DDP which were induced by constant concentration of cisplatin as a resistance modle. When they were cultured to logarithmic phase (about 80%), fully cracking cells to extracting total protein for polyacrylamide gel electrophoresis; PVDF blot was used to receive the protein by using semi-dry process and was incubated with 1%BSA (prepared by TBST) for about 4-6 hours and then with polyclonal cofilin-1 antibody (used at a 1:800 dilution) in the fridge for a night, after washed by TBS, incubated with the second antibody that was labeled with horseradish peroxidase under 37℃for about 3-4 hours, again washde by TBS; the cofilin-1 protein with the antibody was revealed with ECL process and recording with the exposed film.β-actin was choosed as the internal parameter (used at a 1:1000 dilution). Three resultes of Western blot like this was analysed to be gray levels. The software SPSS 13.0 was applied to determine if there was significant difference between A549 and A549/DDP on the expression of cofilin-1.40 cases of pulmonary adenocarcinoma, which were clinically confirmed by Xiang Ya hospital between 1999-2008, were divided into two groups acrodding to the Response Evaluation Criteria in Solid Tumors (RECIST) formulated by WHO in 1979. Sensitive to chemotherapy group (CR+PR, n=20) and resistance to chemotherapy group (PD, n=20). Choice criteria:Cisplatin based chemotherapy at least four circles, no-surgical treatment during the chemotherapy, casebooks were complete. After routine histopathologic section of these paraffin-bedded specimens, expression of cofilin-1 protein was detected by using SP immunohistochemistry. Slices in stead of PBS as the first antibody were used as a negative control and the slices of nomrol epithelial tissue were used as a positive control. Brown or brown yellow grains in cytomembrane, cytolymph and (or) in cyteblast was considered as positive. The software SPSS 13.0 was applied to determine if there was significant difference between sensitive to chemotherapy group and resistance to chemotherapy group on the expression of cofilin-1.RESULTS:The results of the Western blot showed that the expression of cofilin-1 was markedly increased in A549/DDP cell compared with the A549 cell (P<0.05). The positive expression of cofilin-1 was 100% in these lung adenocarcinoma specimens. In resistance to chemotherapy group, strong positive were present 13 cases, positive 6 cases, weak positive 1 case; but in sensitive to chemotherapy group were 4 cases,11 cases,5 cases in turn. There are more cofilin-1 protein expression in the resistance to chemotherapy group than that in the sensitive to chemotherapy group (P<0.05).CONCLUSION:1. Cofilin-1 protein was overexpression in lung adenocarcinoma that resistanced to cisplatin; 2. Cofilin-1 protein was closely related to the cisplatin-resistance of lung adenocarcinoma; 3. Cofilin-1 protein may be a new target protein for reversing cisplatin resistance.