Functional Evaluation Of PSMA-CAR-T Cells Coexpressing IL-7 And CCL19 In The Treatment Of Prostate Cancer

Castration-resistant prostate cancer(CRPC)is a kind of androgen-independent cancer after prostate cancer is treated with androgen deprivation.The probability of its metastasis in the later stage is extremely high.CRPC is in critical need of new and innovative treatment strategies.CAR-T cells have shown remarkable efficacy in the treatment of blood cancers but lagged behind in prostate cancers which with low lymphocytes infiltration named“cold”tumors.Whereas,different cytokines or chemokines such as IL-7 and CCL19 have been shown to enhance the proliferation,survival and tumor infiltration of T cells.We engineered CRPC patient-derived CD4~+and CD8~+T cells specific to protate-specific membrane antigen(PSMA)with coexpressing IL-7 and CCL19 to enable CAR-T cells achieve the survival and infiltration abilities which turn a tumor from“cold”to“hot”,to overcome current limited infiltration of CAR-T therapy in CRPC.We generated a chimeric antigen receptor lentiviral construct encoding the CAR which is specific to PSMA,with IL-7 and CCL19 coexpression using 2A peptide sequence.We produced the lentivirus in a high titer.The CRPC-T cells isolated from periphery blood were transduced by these lentivirus to obtain 7?19-PSMA-CAR-T cells,and the positive rate of CAR-T cells was more than 60%.We found that 7?19-PSMA-CAR-T cells exhibited comparable tumor-lytic activity to the tumor cells which express PSMA and similar cell activation level comparable to PSMA-CAR-T cells in-vitro cytotoxicity experiments.In addition,we observed that 7?19-PSMA-CAR-T cells presented the increased proliferation,a higher proportion of na?ve T cells,and lower expression of exhaustion molecules compared to PSMA-CAR-T cells in vitro.It also had the ability to recruit T cells,DC and CAR-T cells.The further antitumor functions of 7?19-PSMA-CAR-T cells were evaluated using an immunodeficient(NSG)mouse model in vivo.We found that both CAR-T cells had targeting specificity,while 7?19-PSMA-CAR-T cells had enhanced ability to remove PC-3-PSMA~+tumor at day 14 compared to PSMA-CAR-T cells,and this treatment did not cause weight loss.In vivo examination of relevant indexes showed that the CAR-T cells in peripheral blood of mice which were treated with 7?19-PSMA-CAR-T cells could secrete more GzmB and IFN-?and there were more T cell accumulating in the tumor tissues.We reasoned that co-expressing the IL-7 and CCL19with a PSMA specific CAR in mCRPC T cells could be a promising strategy in treating castrate-resistant prostate cancer resulting in enhanced proliferation,infiltration and efficacy.