Objective:

2

To explore the anti-tumor effect of safflower yellow (SY) against hepatocellular carcinoma (HCC) and the underlying potential mechanism.

Methods:

2

An

in vitro

model was established by mixing Luc-Hepa1-6 cells and CD3

+

CD8

+

T cells

followed by adding programmed cell death protein 1 (PD-1) antibody (Anti-mPD-1) with or without SY. The apoptosis was detected by flow cytometry and the level of inflammatory cytokines was determined by enzyme-linked immunosorbent assay. The protein levels of programmed cell death 1 ligand 1 (PD-L1)

chemokine ligand (CCL5)

C-X-C motif chemokine ligand 10 (CXCL10) were measured by Western blot. An

in situ

animal model was established in mice followed by treatment with anti-mPD-1 with or without SY. Bioluminescence imaging was monitored with an AniView 100 imaging system. To establish the FAK-overexpressed Luc-Hepa1-6 cells

cells were transfected with adenovirus containing pcDNA3.1-FAK for 48 h.

Results:

2

The fluorescence intensity

apoptotic rate

release of inflammatory cytokines

and CCL5/CXCL10 secretion were dramatically facilitated by anti-mPD-1 (

P

<

0.01)

accompanied by an inactivation of PD-1/PD-L1 axis

which were extremely further enhanced by SY (

P

<

0.05 or

P

<

0.01). Increased fluorescence intensity

elevated percentage of CD3

+

CD8

+

T cells

facilitated release of inflammatory cytokines

inactivated PD-1/PD-L1 axis

and increased CCL5/CXCL10 secretion were observed in Anti-mPD-1 treated mice (

P

<

0.01)

which were markedly enhanced by SY (

P

<

0.05 or

P

<

0.01). Furthermore

the enhanced effects of SY on inhibiting tumor cell growth

facilitating apoptosis and inflammatory cytokine releasing

suppressing the PD-1/PD-L1 axis

and inducing the CCL5/CXCL10 secretion in Anti-mPD-1 treated mixture of Luc-Hepa1-6 cells and CD3

+

CD8

+

T cells were abolished by FAK overexpression (

P

<

0.01).

Conclusion:

2

SY inhibited the progression of HCC by mediating immunological tolerance through inhibiting FAK.