Published online Feb 7, 2018. doi: 10.3748/wjg.v24.i5.593
Peer-review started: August 27, 2017
First decision: September 12, 2017
Revised: September 26, 2017
Accepted: November 21, 2017
Article in press: November 21, 2017
Published online: February 7, 2018
Processing time: 157 Days and 16.1 Hours
To study the role of semaphorin 4D (Sema4D) expression promoted by tumor-associated macrophages (TAMs) in gastric carcinoma cells and its clinical significance in the invasion and metastasis of gastric carcinoma.
CD68 and Sema4D expression was analyzed in gastric carcinoma and adjacent normal tissues from 290 patients using the immunohistochemical streptavidin-peroxidase method, and their relationships with clinicopathological features were evaluated. Human M2 macrophages were induced in vitro and co-cultured in non-contact with gastric carcinoma SGC-7901 cells. Changes in the secretory Sema4D level in the SGC-7901 cell supernatant were measured using an enzyme-linked immunosorbent assay. The effects of TAMs on SGC-7901 cell invasion and migration were assessed with invasion and migration assays, respectively.
CD68 and Sema4D protein expression was significantly higher in gastric carcinoma tissues than in adjacent normal tissues (71.7% vs 33.8% and 74.5% vs 42.8%, respectively; P < 0.01). CD68 and Sema4D protein expression was significantly associated with histological differentiation, TNM stage, and lymph node metastasis (P < 0.05), and their expression levels were positively correlated with one another (r = 0.467, P < 0.01). In the in vitro experiment, secretory Sema4D protein expression was significantly increased in the supernatant of SGC-7901 cells co-cultured with TAMs compared with the blank control (1224.13 ± 29.43 vs 637.15 ± 33.84, P < 0.01). Cell invasion and metastasis were enhanced in the Transwell invasion and migration assays (P < 0.01).
TAMs promote the invasion and metastasis of gastric carcinoma cells possibly through upregulated secretory Sema4D protein expression. Combined detection of TAM markers, CD68 and Sema4D, in gastric carcinoma tissue shows potential to predict the trend of gastric carcinoma progression.
Core tip: This study explored the role and clinical significance of semaphorin 4D (Sema4D) expression promoted by tumor-associated macrophages (TAMs) in gastric carcinoma cells. By using immunohistochemical streptavidin-peroxidase method on tissue species and gastric carcinoma cells in non-contact co-culture with human M2 macrophages in vitro, we found that Sema4D protein expression was significantly higher in gastric carcinoma tissues than in adjacent normal tissues, and TAMs promoted the invasion and metastasis of gastric carcinoma cells possibly through upregulated Sema4D protein expression.