| Background:Adoptive transfer of tumor infiltrating or circulating lymphocytes transduced with tumor antigen receptors has been examined in various clinical trials to treat human cancers. The tumor antigens targeted by transferred lymphocytes affects the efficacy of this therapeutic approach. Because cancer stem cells (CSCs) play an important role in tumor growth and metastasis, we hypothesized that adoptive transfer of T cells targeting a CSC antigen could result in dramatic anti-tumor effects.Methods:First, we designed and synthesized an EpCAM specific CAR (EpCAM.CAR).The CAR and LUC2 gene was inserted into a pLNCX retroviral vector, respectively. Retroviruses were produced using the retrovirus packaging kit, Ampho (Takara) and the 293 T packaging cell line. pLNCX-LUC2 retrovirus was transduced the tumor cell lines to establish Hela-luc, Huh7-luc, PC3-luc and PC3M-luc stable cell lines. Cell-based bioluminescent imaging was used to investigate if PBLs transduced with the EpCAM-specific CAR can specifically target EpCAM+cells. To examine the tumor-killing abilities of CAR-expressing PBLs in vivo, we injected PC3M-luc tumor cells into NOD/SCID mice intraperitoneally. To examine the effect of CAR-expressing PBLs on lung tumor metastasis in vivo, we injected PC3-luc tumor cells into the tail vein of NOD/SCID mice.Results:An EpCAM-specific chimeric antigen receptor (CAR) was constructed to transduce human peripheral blood lymphocytes (PBLs) and thereby enable them to target the CSC marker EpCAM. To investigate the therapeutic capabilities of PBLs expressing EpCAM-specific CARs, we used two different tumor models, PC3, the human prostate cancer cell line, which has low expression levels of EpCAM, and PC3M, a highly metastatic clone of PC3 that has high expression levels of EpCAM. We demonstrate that CAR-expressing PBLs can kill PC3M tumor cells in vitro and in vivo. Despite the low expression of EpCAM on PC3 cells, CAR-expressing PBLs significantly inhibited tumor growth and prolonged mouse survival in a PC3 metastasis model, probably by targeting the highly proliferative and metastatic population of cancer cells.Conclusions:Our data demonstrate that PBLs expressing with EpCAM-specific CARs have significant anti-tumor activity against prostate cancer. Therefore, the adoptive transfer of T cells targeting EpCAM could have great potential as a cancer treatment.Objective:Triple negative breast cancer (TNBC) is defined by a lack of expression of estrogen receptor, progesterone receptor, and HER2/neu. and considered to be a clinicopathologic entity with aggressive behaviors and poor prognosis. No satisfactory treatment is available. This study was to analyze the effects of radiofrequency ablation(RFA) on immune systerm, in situ tumor and lung metastasis in a triple negative breast cancer model 4T1. Methods A total of 5×104 4T1 cells in 50μl of PBS were s.c. injected into the right femur of female Balb/C mice. Fourteen days later, tumors were selected for ablation when their diameter measured 6-8 mm.We examined the splenic lymphocyte subsets by flow cytometry at different time points after RFA.14 days after treatment, we sacrificed the control group and treatment group mice, counted the number of lung metastasis nodule, detected the changes of splenic lymphocyte subsets by flow cytometry. Results Radiofrequency ablation can basically eliminate the in situ tumor with low local tumor recurrence rate;After RFA,an increased amount of the spleen derived CD4+T cells,CD8+T cells, B cells, NK and NKT cells was found. RFA significantly inhibited the occurrence of 4T1 lung metastasis(P<0.05), accompanied by the increase of CD4+T cells,CD8+T cells,B cells and NK cells,and the decrease of myeloid-derived suppressor cells (MDSC).Conclusions RFA can enhance anti-tumor immunization and effectively inhibited lung metastasis, and suggests that RFA could have great potential in TNBC treatments and controlling the distal metastasis. |
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