title: Induction of CTLs by DCs pulsed with K-ras mutant peptide on the surface of nanoparticles in the treatment of pancreatic cancer.
abstract: The aim of this study was to investigate the role of specific cytotoxic T lymphocytes (CTLs) activated by dendritic cells (DCs) presenting cationic nanoparticles with the K-ras (12-Val) mutant peptide in the killing of different pancreatic cancer cell lines in vivo and in vitro. Peripheral blood DCs were induced by rhGM-CSF and IL-4 and cultured. DCs were sensitized by whole antigen of PANC-1 with expression of K-ras mutant, K-ras mutant peptide (K-ras+peptide) and cationic nanoparticles with K-ras mutant peptide (K-ras+peptide-CNP), respectively. Cell surface markers were measured by flow cytometry. Lymphocyte proliferation was detected by the 3H-TdR test, and IL-12 and IFN‑γ secretion was detected by ELISA. 125I-UdR was used to measure the killing effect of CTLs. The antitumor activity of CTLs in tumor-bearing nude mouse models prepared with PANC-1 and SW1990 cells was evaluated. Results showed that, compared with K-ras+peptide, low concentrations of K-ras+peptide-CNP were effectively presented by DCs (P<0.05). CTLs induced by DCs pulsed with whole tumor antigen had a significantly greater killing effect (P<0.05) on PANC-1 and SW1990 pancreatic cancer cells compared with K-ras+peptide- and K-ras+peptide-CNP-induced CTLs. CTLs induced by DCs pulsed with K-ras+peptide and K-ras+peptide- CNP had a specific killing effect (P<0.05) on PANC-1 cells and no effect (P>0.05) on SW1990 cells. In conclusion, cationic nanoparticles with the K-ras (12-Val) mutant peptide can be effectively presented by DCs at a low concentration. CTLs induced by K-ras+peptide-CNP had specific killing activity for the pancreatic cancer cell line with the K-ras mutant and significantly inhibited tumor growth and increased the survival time of tumor-bearing nude mice. Although this study confirmed that whole cell antigen induced a good antitumor immune response, the possibility of immune tolerance and autoimmunity which has been previously proven contribute to the difficulty in the application of this DC vaccine.
authors.affiliation: Department of General Surgery, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, PR China.
authors.forename: Guang
authors.initials: G
authors.lastname: Tan
authors.forename: Zhongyu
authors.initials: Z
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhengang
authors.initials: Z
authors.lastname: Cai
authors.forename: Junkai
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000166:cytology*; D015972:Gene Expression Regulation, Neoplastic; D011905:Genes, ras; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D010455:Peptides / Q000737:chemistry; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology; D018631:ras Proteins / Q000378:metabolism*
chemical_list: D010455:Peptides; D018631:ras Proteins