It was well known that cancer-associated fibroblasts (CAFs) were an essential factor in tumor progression. KLF5 in CAFs might be considered as a encouraging target for the treatment of gastric malignancy. 0.05 by t test, ** 0.01 by t test. We further investigated the mRNA and protein expression of KLF5 in CAFs BKM120 inhibition and NFs using qRT-PCR and Western blotting assay, the results indicated that KLF5 mRNA and protein expression were also all significantly up-regulated in CAFs compared with corresponding NFs (Physique?1B-D). The overexpression of KLF5 in gastric malignancy stroma is related to poor individual prognosis The tissue microarray contains BKM120 inhibition 120 gastric malignancy tissues after radical surgery were stained for KLF5 protein expression via immunohistochemistry. Two impartial pathologists were blinded to the specific diagnosis for the stained slides and collection of clinical information. The staining intensity was scored on a scale range from 0 to 3. After dividing the patients into two groups with high or low level of KLF5 expression in gastric malignancy stroma according to the median score. The results showed that the level of KLF5 expression in gastric malignancy stroma was significantly related to tumor size (P = 0.004), grade (P = 0.017), invasive depth (P = 0.016), and lymph node metastasis (P = 0.005) (Table?1). Moreover, the higher level of KLF5 expression in the stroma underwent a shorter overall survival (P = 0.04, Fig.?1F) in the analysis of Kaplan-Meier survival, which suggesting that KLF5 in gastric malignancy stroma might be a favorable important factor in the development of gastric malignancy. Table 1. Relationship between KLF5 expression in gastric malignancy stroma and clinicopathologic features. value 0.05 by t test, ** 0.01 by t test. Transwell migration assay indicated that this migration ability of gastric cells cultured with CAFs transfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly greater and weaker than the corresponding control, respectively (Fig.?2C and ?andD).D). Transwell invasion assay indicated that this invasion ability of gastric cells cultured with CAFs transfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly greater and weaker than the corresponding control, respectively (Fig.?2E and ?andFF). Wound-healing assay revealed that this wound closure rate of gastric cells cultured with CAFs transfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly higher and lower than corresponding control, respectively (Fig.?3A and ?andB).B). All these data suggested that this CM from CAFs with KLF5 low expressions significantly inhibit gastric malignancy cells growth, migration and invasion, whereas CAFs with KLF5 high expression could significantly promote the growth, migration and invasion of gastric malignancy cells. Open in a Pparg separate window Physique 3. Down-regulation of KLF5 expression in CAFs inhibits the migration of gastric malignancy cells and the tumor growth in vivo. (A, B) Cell migration ability was also measured by a wound-healing assay. The wound closure rate of gastric cells cultured with CAFs tranfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly higher and lower than corresponding control, respectively. (C, D) Tumor growth ability was measured by a tumor xenograft assay. The tumor volume of mice injected gastric malignancy cells cultured with CAFs transfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly bigger and smaller than corresponding control, respectively. The tumor excess weight of mice injected gastric malignancy cells cultured with CAFs transfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly heavier and lighter than corresponding control, respectively. Data symbolize imply SEM from three impartial experiments. * 0.05 by t test, ** 0.01 by t test. We further tested whether abnormal expression of KLF5 in CAFs impact tumor cells growth in vivo. Tumor xenograft assay showed that this tumor volume of mice injected tumor cells together with CAFs transfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly bigger and smaller than corresponding control, respectively (Fig.?3C). The tumor excess weight of mice BKM120 inhibition injected gastric malignancy cells cultured with CAFs transfected lentivirus-KLF5 and lentivirus-siRNA-KLF5 was significantly heavier and lighter than corresponding control, respectively (Fig.?3D), which suggesting that CAFs with KLF5 low expression could significant inhibit gastric malignancy growth, whereas CAFs with KLF5 high expression promote gastric BKM120 inhibition malignancy growth in vivo, consistent with the data obtained from assays in vitro. KLF5-regulating CAFs impact tumor cell progression by CCL5/CCR5 axis To further reveal the exact mechanism of the inhibitory effect of KLF5-downregulating CAFs on tumor cell progression, we decided cytokine expression difference between CAFs-CM and CAFs-KLF5-si-CM using human cytokine antibody.