Study on the immune responses against pancreatic cancer induced by mucin 4 and human telomerase reverse transcriptase mRNA co-transfected dendritic cells in vitro

Abstract

Objective To investigate the anti-tumor immune response induced by human pancreatic cancer mucin 4 mRNA and human telomerase reverse transcriptase (hTERT) mRNA cotransfected dendritic cells (DC),and to provide the experimental evidences for the treatment of pancreatic cancer with multi-epitope loaded DC vaccine.Methods DC were isolated from peripheral blood mononuclear cells (PBMC) of six patients with HLA-A2+ pancreatic cancer and cultured.Mucin 4 mRNA and hTERT mRNA were transcripted and amplified in vitro,which were transfected into DC separately or in order by eleetroporation.DC were cultured for 48 hours.The expressions of mucin 4 and hTERT in DC were detected by quantitative real-time polymerase chain reaction (PCR) and Western blot.The survival rates of transfected DC were determined by methylthiazolyl tetrazolium (MTT) method.The cytotoxic T lymphocyte (CTL) activation induced by mucin 4 mRNA and hTERT mRNA transfected DC were evaluated by interferon (IFN)-γ release assays (enzyme linked immunosorbent assay) method.The cytotoxicity of CTL induced by mucin 4 mRNA and hTERT mRNA transfected DC in pancreatic cancer cell lines MiaPaCa-2,Capan-2,AsPC-1 and Pane-1 was measured by 51Cr standard cytotoxicity test.Student t test was performed for statistical analysis.Results After in order transfection of mucin 4 mRNA and hTERT mRNA for 48 h,the relative quantity of the expression of mucin 4 and hTERT in DC were 30.09±5.24 and 12.87±3.36,which were lower than the relative quantity of the expression in DC transfected separately (38.54±6.21 and 36.35±5.03,t=3.469,6.721,both P＜0.05).After transfected in order for 96 hours,the survival rate of DC decreased to 52.17％,which was lower than that of DC transfected separately (around 80％).The quantity of IFN-γ releasing of specific CTL induced by mucin 4 mRNA and hTERT mRNA cotransfected DC was (32.57±2.01) U/mL in 24 hours,which was higher than that of CTL induced by DC transfected with mucin 4 mRNA ((23.06±4.74) U/mL) or hTERT mRNA ((16.82±3.67) U/mL) separately (1=5.092,7.141,both P＜0.05).After co-transfected with mucin4 mRNA and hTERT mRNA,DC could effectivly induce HLA-A2+/mucin 4+/hTERT+ specific CTL immune responses,however there was no significant cytotoxicity in HLA-A2+ pancreatic cancer cells.Conclusion The induction of CTL anti-tumor immune response by DC co-transfected with mucin4 mRNA and hTERT mRNA is more significant compared with that by single antigen loaded DC. Key words: Dendritic cells; Mucins; Telomerase; RNA, messenger; Pancreatic neoplasms; T-lymphocytes, cytotoxic