Improvement of cytotoxicity of autologous CIKs from patients with breast cancer to MCF-7 cells by suppressed PD-1 expression.

OBJECTIVE: To investigate the improvement of cytotoxicity of autologous CIKs from patients with breast cancer to MCF-7 cells by suppressed PD-1 expression.

METHODS: The Lentiviral Vector/PD-1 carrying the gene that can suppressed PD-1 was transferred to CIK cells from patients with breast cancer to inhibit PD-1 expression. The PD-1 protein were detected by RT-PCR and Western blot. The positive PD-1 of CIKs and PD-L1 of MCF-7 cells were detected by FCM, and cytotoxicity of CIKs to MCF-7 was assayed by CCK-8.

RESULTS: The PD-1 positive CIKs with Lentiviral Vector/PD-1 transferred from patients with breast cancer were 16.02%, 14.36% and 14.64% at 14th, 21st and 28th day, obviously inhibited as compared to 50.54%, 74.50% and 73.36% in CIKs without transinfection (P< 0.05); the Lentiviral Vector/PD-1 decreased the PD-1 mRNA levels in CIK cells, and Lentiviral Vector/PD-1-transferred CIKs had lower PD-1 expression; CCK-8 detection showed that at 14th day, the cytotoxicity rates of CIKs with blank plasmids and those with PD-1 transfection to MCF-7 cells were 58.78% and 68.14%, respectively.

CONCLUSION: MCF-7 cells have a strong PD-L1 expression at its surface, and inhibition of PD-1 expression can improve the cytotoxicity of CIK cells.