OBJECTIVETo screen and obtain the validate immunogenic membrane antigens in pancreatic cancer.

METHODSPancreatic cancer cell line SW1990 membrane protein was extracted and separated by two-dimensional gel electrophoresis (2-DE). One of the three parallel 2-DE gels underwent Coomassie blue staining while the other two underwent immunoblot. Serum IgG was purified from clinically collected sera of 66 pancreatic cancer patients and 24 chronic pancreatitis patients and used as the primary antibody of the immunoblot. Positive dots of immunoblot were identified by MALDI-TOF mass spectrometry and PMF matching. The candidate membrane antigens were further validated respectively in cell lines and tissues by RT-PCR, real-time PCR, Western blot, and their different expression level of gene and protein between pancreatic cancer cell line and normal pancreatic tissue were compared studied.

RESULTSThe immunoblot of SW1990 membrane protein with serum IgG from cancer patients showed nine positive dots which were not the same as those from immunoblot with serum IgG from chronic pancreatitis patients. One talent dot was identified with MALDI and PMF as VDAC2. RT-PCR and real-time PCR showed that the gene of VDAC2 was expressed in the pancreatic cancer cell line. Western blot showed that the expression of protein level of VDAC2 in the pancreatic cancer cell line was obviously higher than in normal pancreatic tissue.

CONCLUSIONSVDAC2 might be the candidate immunogenic membrane antigens of pancreatic cancer, and its gene is all expressed in the pancreatic cancer cell line SW1990, AsPc and P3. The protein level of VDAC2 is significantly overexpressed in pancreatic cancer cell line than in normal pancreatic tissue.