Dendritic cells reconstituted with a human heparanase gene induce potent cytotoxic T-cell responses against gastric tumor cells in vitro.
OBJECTIVE
Dendritic cell-based tumor vaccination is a promising approach in the treatment of cancer. Strategies to modify dendritic cells (DCs) with tumor-associated antigens (TAAs) can elicit specific immune responses against tumors. Heparanase is overexpressed in gastric cancer, especially in invasive and metastatic cells, but is downregulated in differential normal tissue. Therefore, heparanase is a potential target in immunotherapy for patients with advanced gastric cancer who are not candidates for surgery. The present paper was designed to investigate the immune response of a heparanase gene-modified DC-based vaccine against gastric cancer cell lines in vitro.


METHODS
DCs from peripheral blood mononuclear cells of healthy HLA-A2-positive donors were transfected with recombinant adenovirus containing the full-length cDNA of heparanase (rAd-Hpa) to generate heparanase gene-modified DC vaccine. T lymphocytes from the same donors were repeatedly activated by genetically modified DC vaccine to generate heparanase-specific cytotoxicity T lymphocytes (CTLs). CTL-mediated cell lysis of gastric cancer cells lines (KATO-III and SGC-7901) was analyzed in vitro by a standard (51)Cr releasing assay. IFN-gamma secretion was measured by ELISA in heparanase-specific CTLs cocultured with those gastric cancer cell lines.


RESULTS
Our results showed that the expression of heparanase in DCs transfected with rAd-Hpa was significantly increased. Furthermore, DCs transfected with rAd-Hpa could induce heparanase-specific CTLs against HLA-matched and heparanase-positive gastric cancer cells in vitro, while there were no killing effects on autologous lymphocytes. Meanwhile, these rAd-Hpa-modified DCs could increase IFN-gamma secretion of effector cells when cocultured with KATO-III cells.


CONCLUSIONS
These findings demonstrate for the first time that the transduction of DCs with rAd-Hpa can induce CTLs that specifically lyse heparanase-positive gastric cancer cells and increase IFN-gamma secretion in an MHC-restricted fashion. Heparanase gene-modified DC vaccine offers a great opportunity for immunotherapy in patients with advanced gastric cancer and possibly also with other malignancies.
Cai
Yong-Guo
YG
Institute of Gastroenterology of PLA, Southwest Hospital, Third Military Medical University, Chongqing, China.
Fang
Dian-Chun
DC
Chen
Ling
L
Tang
Xu-Dong
XD
Chen
Ting
T
Yu
Song-Tao
ST
Luo
Yuan-Hui
YH
Xiong
Zheng
Z
Wang
Dong-Xu
DX
Yang
Shi-Ming
SM
D000256:Adenoviridae / Q000378:metabolism; D045744:Cell Line, Tumor; D003713:Dendritic Cells / Q000166:cytology* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D005966:Glucuronidase / Q000096:biosynthesis*; D015789:HLA-A2 Antigen / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D007167:Immunotherapy / Q000379:methods; D007371:Interferon-gamma / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000628:therapy*; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism*; D000099175:Heparanase
D005966:Glucuronidase; D015789:HLA-A2 Antigen; D007371:Interferon-gamma; D010455:Peptides; D000099175:Heparanase