Objective:

2

To investigate the inhibitory effects of paeoniflorin on migration- and invasionpromoting capacities of gastric cancer associated fibroblasts (GCAFs) and to explore the molecular mechanism underlying the effects.

Methods:

2

Paired gastric normal fibroblast (GNF) and GCAF cultures were established from resected tissues. GCAFs were treated with control medium

or 2.5

5 or 10 μg/mL paeoniflorin. Conditioned media were prepared from GNFs

GCAFs

control-treated GCAFs and paeoniflorin-treated GCAFs

and used to culture AGS human gastric cancer cells. The migration and invasion capacities of AGS cells were determined with wound healing test and transwell invasion assay

respectively. The interleukin 6 (IL-6) mRNA and microRNA-149 expression in GCAFs were detected by reverse transcription-quantitative polymerase chain reaction. The IL-6 protein expression and secretion by GCAFs were measured with Western blot and enzymelinked immunosorbent assay analysis

respectively. The protein levels of phosphorylated signal transducer and activator of transcription 3 (STAT3)

matrix metalloproteinase (MMP) and MMP9 in AGS cells were examined by Western blot.

Results:

2

GCAFs displayed enhanced capacities to induce AGS cell migration and invasion as compared with GNFs. Paeoniflorin treatment significantly inhibited the migration- and invasion-promoting capacities of GCAFs (

P

<

0.05). GCAFs produced and secreted more IL-6 into the conditioned medium than GNFs

leading to over-activation of STAT3-MMP signaling in AGS cells. Paeoniflorin suppressed IL-6 production and secretion by up-regulating microRNA149 expression in GCAFs

and subsequently prevented GCAFs from activating IL-6-STAT3-MMP signaling of AGS cells.

Conclusions:

2

Paeoniflorin inhibits the migration- and invasion-promoting capacities of GCAFs by targeting microRNA-149 and IL-6. Paeoniflorin is potentially a novel therapeutic agent against cancer microenvironment.