To investigate the expression of 3’-phosphoadenosine-5’-phosphosulfate synthase 2 (PAPSS2) in gastric cancer tissues and cells and its effects on the invasion and migration of gastric cancer cells.

The expression of PAPSS2 in gastric cancer were analyzed using the GEPIA database. The tissue specimens of 40 gastric cancer patients from October 2016 to June 2018 in Shaanxi Provincial People’s Hospital were collected for immunohistochemical staining. The association between PAPSS2 expression and clinicopathological data and prognosis of the gastric cancer patients was analyzed. The expression levels of PAPSS2 in gastric cancer cells (HGC-27, SNU-1, AGS and SGC-7901) and normal gastric mucosa cell line (GES-1) were tested by qPCR and Western blotting. The expression of PAPSS2 in gastric cancer cells was knocked down using shRNA, its effect on cell activity was detected using MTT, and its effect on invasion and migration ability was detected using Transwell method.

(1) PAPSS2 was highly expressed in gastric cancer tissues according to GEPIA database (P<0.05). The overall survival rate (HR=1.5, P=0.017) and disease-free survival rate (HR=1.6, P=0.014) of patients with high PAPSS2 expression was significantly reduced. (2) Immunohistochemical staining revealed that the expression of PAPSS2 was significantly higher in gastric cancer tissues than in the corresponding paracancerous tissues (7.100±3.169 vs 3.425±2.263, P<0.001). Patients with high PAPSS2 expression had greater depth of invasion (P=0.015) and a higher rate of lymphatic metastasis (P=0.005). (3) qPCR results showed that the mRNA expression levels of PAPSS2 in gastric cancer cells (HGC-27, SNU-1, AGS and SGC-7901) were significantly higher than those in GES-1 cells. Similar results were obtained by Western blotting. (4) MTT assay showed that the knockdown of PAPSS2 had no significant effect on the activity of AGS and SGC-7901 cells. (5) The invasion and migration ability of AGS cells and SGC-7901 cells was significantly reduced after the PAPSS2 knockdown (P<0.05).

PAPSS2 is highly expressed in tissues and cells of gastric cancer, and its high expression promotes the invasion and metastasis of gastric cancer cells, which may be one of the important reasons for the poor prognosis of patients with gastric cancer.