Objective      To construct a phage display library and screen phage-displayed single-chain variable fragment (scFv) antibody against ATP-binding cassette sub-family G member 2 (ABCG2) of lung adenocarcinoma.       Methods      Total RNA of positive lymph nodes adjacent to lung adenocarcinoma was extracted. Variable regions of heavy (VH) and light chain (VL) were amplified by PCR. ScFv gene was synthesized by SOE-PCR

and then linked to a pCANTAB5E phagemid vector to finally creat

e a phage displayed scFv library. Six rounds of biopanning against A549 cells and ABCG2 antigen were performed. The properties of the product were identified by Western blotting

and its specificity was detected by ELISA and immunocytochemical assay. CCK8 assay was used to detect its effect on cisplatinsensitization.       Results      A phage displayed scFv antibody against ABCG2 of lung cancer was successfully constructed. The obtained scFv antibody had an apparent molecular weight of 34×10

3

and significantly down-regulated the expression of ABCG2 protein in A549 cells. Besides

it demonstrated a relative specific affinity to A549 cells and ABCG2 antigen with a positive recognition rate of 75%. Furthermore

it increased the cisplatin sensitivity in A549 cells with distinctly reduced IC

50

values.       Conclusion      A phage displayed anti-ABCG2 scFv of lung cancer is successfully constructed

and through it

scFv antibody is screen out which can specifically bind to single-chain antibodies. This study found a strong basis for  subsequent body visualization research and lung cancer stem-like cells targeting ABCG2.