ABSTRACT
Objective To investigate the inducing effects of chemokines [fractalkine (FKN), IP-10] and different signal pathway inhibitors on NK cells in the tumor microenvironment (TME). Methods Immunohistochemistry was performed using antibodies for CD56 and DAP10 respectively on human breast carcinoma. Murine macrophages (RAW 264.7) and breast cancer cells (4T1) were co-cultivated at a 1:4 ratio to imitate the TME with NK cells (KY-1) set as the object. RT-PCR was used to determine the mRNA expressions of CD16, NKG2D and NK1.1, and the content of CD107a in the supernatants was determined by ELISA. 10ng/ ml FKN and 10ng/ml IP-10 were added into the TME, NK1.1+CD16+KY-1 cells were counted with flow cytometry, migration and adhesion assays were used to assess the related function of KY-1 cells. 4T1 cells were incubated in 10nmol/L of rapamycin, 30μmol/ L of LY294002, 500ng/μl of andrographolide and 2mmol/L of wortmannin, the 4T1 tumor supernatants (TSNs) were harvested separately and used to incubate RAW 264.7 for 48h, then the expressions of Rae1α and H60a mRNA in 4T1, RAW 264.7 and their mixture were determined by RT-PCR. Results The related indicators of KY-1 cells such as NK1.1+ number, chemotaxis rate, and adhesion function decreased obviously in TME, and the above indices increased after the addition of FKN and IP-10, and some signal pathway inhibitors indirectly promoted NK cells' function in TME, and among them rapamycin was the most efficient one (P<0.05). Conclusion FKN and IP-10 may up-regulate the number and function of NK cells in TME, and rapamycin can promote NK cells' killing function by inducing high expression of NKG2DLs (Rae1, H60a) on tumor cells.