Generation and Functional Characterization of PLAP CAR-T Cells against Cervical Cancer Cells

Abstract

Chimeric antigen receptor (CAR) T cell therapy is one of the cancer treatment modalities that has recently shown promising results in treating hematopoietic malignancies. However, one of the obstacles that need to be addressed in solid tumors is the on-target/off-tumor cytotoxicity due to the lack of specific tumor antigens with low expression in healthy cells. Placental alkaline phosphatase (PLAP) is a shared placenta/tumor-associated antigen (TAA) that is expressed in ovarian, cervical, colorectal, and prostate cancers and is negligible in normal cells. In this study, we constructed second-generation CAR T cells with a humanized scFv against PLAP antigen, then evaluated the characteristics of PLAP CAR T cells in terms of tonic signaling and differentiation in comparison with ΔPLAP CAR T cells and CD19 CAR T cells. In addition, by coculturing PLAP CAR T cells with HeLa cells, we analyzed the tumor-killing function and secretion of anti-tumor molecules. Results showed that PLAP CAR T cells not only could eliminate the cancer cells but also increase their proliferation in vitro. We also observed increased secretion of IL-2, granzyme A, and IFN-γ by PLAP CAR T cells upon exposure to the target cells. In conclusion, PLAP CAR T cells are potential candidates for further investigation in cervical cancer and potentially other solid tumors.

EGFR inhibition in lung adenocarcinoma upregulates cell surface expression of the placental antigen ALPP and enhances efficacy of ALPP-ADC therapy

“…ALPP and ALPPL2 are closely related and regulated GPI anchored proteins that are known to be expressed on the cell surface in some cancers, whereas normal tissue expression is largely limited to the placenta [3,6]. ALPP and ALPPL2 are currently being explored as cancer therapy targets [5,7,8,9]. However, limited expression levels of ALPP/ALPPL2 in most cancer types may restrict its broader therapeutic potential.…”

“…ALPP-CAR-T cells mediated potent cytotoxicity towards cancer cells, while the combination of ALPP-CAR-T cells with anti-PD-1, PD-L1, or LAG-3 checkpoint inhibitors further increased the therapeutic efficacy of CAR T-cells [5]. Second-generation CAR T-cells with a fully human scFv against ALPP antigen effectively killed ALPP-expressing HeLa cells [8]. A clinical trial using α-ALPP CAR T cells for ovarian and endometrial cancer has been initiated, while another clinical study evaluating the efficacy of ALPP/ALPPL2 antibody-drug conjugate in advanced solid tumors is ongoing [9].…”

T cell immunotherapy for cervical cancer: challenges and opportunities

“…The researchers also observed increased secretion of IL-2, granzyme A, and IFN-g after PLAP CAR-T cells were exposed to target cells. Therefore, it was concluded that PLAP CAR-T cells are potential candidates for further study of cervical cancer and other solid tumors (75).…”