title: Cytotoxicity of lymphocytes activated by superantigen toxic-shock-syndrome toxin-1 against colorectal cancer LoVo cells.
abstract: Toxic-shock-syndrome toxin-1 (TSST-1), a superantigen, can stimulate T cell activation and be used for immunotherapy. In this study, we employed the carcinoembryonic antigen (CEA)-positive LoVo cells to test whether retrovirus-mediated TSST-1 expression could activate human T cells and promote cytotoxicity against tumor cells. We first generated plasmids of pLEGFP-N1-5HRE-CEAp-TSST-1-linker-CD80TM containing a fusion gene of the CEA promoter, 5 copies of the hypoxia-response elements (HRE) as an enhancer, the fragments for TSST-1, and the transmembrane domain of CD80 (CD80TM) and control pLEGFP-N1-5HRE-CEAp (without TSST-1) and generated retroviruses of 5HCTC and 5HC, respectively. After infection with 5HC and 5HCTC retroviruses to establish cell lines, the high levels of TSST-1 expression were observed on the membrane and cytoplasm of the 5HCTC-infected LoVo cells, particularly culture under a hypoxic condition, but not on CEA(-) HeLa cells. Furthermore, the TSST-1-expressing LoVo cell lysates, but not the control cell lysates, stimulated human T cell proliferation, and the co-culture of the TSST-1-expressing LoVo, but not control cells, with human peripheral blood mononuclear cells (PBMC) induced a high frequency of TNF-α- and IL-2-secreting T cells in vitro, particularly under hypoxic conditions. More importantly, co-culture of the TSST-1-expressing LoVo cells, particularly under hypoxic conditions, but not control cells, with different numbers of PBMC promoted potent cytotoxicity against LoVo cells in a dose-dependent manner in vitro. These data provide proof of the principle that selective induction of TSST1 expression in CEA(+) colorectal cancer (CRC) cells activates T cells that destroy tumor cells, particularly under a hypoxic condition. Therefore, our findings may aid in the design of new immunotherapy for the intervention of CRC at clinic.
authors: Department of General Surgery, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, People's Republic of China. macabre1012@126.com
authors: Wei
authors: W
authors: Wang
authors: Xuejun
authors: X
authors: Sun
authors: Le
authors: L
authors: Lu
authors: Jian-Bao
authors: JB
authors: Zheng
authors: Yong
authors: Y
authors: Tian
authors: Wei
authors: W
authors: Wang
mesh_terms: D018122:B7-1 Antigen / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D002272:Carcinoembryonic Antigen / Q000378:metabolism; D015687:Cell Hypoxia / Q000235:genetics; D045744:Cell Line, Tumor / Q000821:virology; D049109:Cell Proliferation; D018920:Coculture Techniques; D015179:Colorectal Neoplasms / Q000276:immunology / Q000473:pathology*; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods; D004306:Dose-Response Relationship, Immunologic; D004768:Enterotoxins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D007376:Interleukin-2 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000502:physiology*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020218:Response Elements / Q000235:genetics; D012190:Retroviridae / Q000235:genetics; D018089:Superantigens / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D018122:B7-1 Antigen; D001427:Bacterial Toxins; D002272:Carcinoembryonic Antigen; D004768:Enterotoxins; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; D018089:Superantigens; D014409:Tumor Necrosis Factor-alpha; C030107:enterotoxin F, Staphylococcal