Fig. 6
DPEP1 suppresses the cytotoxic function of human peripheral blood NK (PBNK) cells. (A) Target cells (K562, HCT116, and KM12C) were either treated with rDPEP1, transfected to overexpress DPEP1, or subjected to DPEP1 knockdown, then labeled with Calcein-AM. Labeled cells were co-cultured with human PBNK cells at an E: T ratio of 2:1. Cytotoxicity was assessed by quantifying Calcein released into the culture medium. (B) PBNK cells were co-cultured with SW480, HCT116, or KM12C cells with DPEP1 overexpression or knockdown, in the presence or absence of rDPEP1 (0.1 µg/mL). After 12 h, granzyme B levels in the culture medium were measured. (C) HCT116 cells were co-cultured with PBNK cells with or without rDPEP1. After incubation, cell lysates were collected, and western blotting was performed to detect granzyme B and perforin 1 protein levels. Data represent mean ± SD from three independent experiments (n = 3), each performed in triplicate. Statistical significance was assessed using Student’s t-test (*P < 0.05, **P < 0.01, P***<0.001).
