Background and purpose: Peroxiredoxin Ⅱ (PrxⅡ) has the activity of peroxidase. The relevant studies found it played an important role in gastric cancer. This study aimed to investigate the expression of PrxⅡ in human gastric cancer tissues and cells, analyze its relationship with clinicopathological characteristics, and explore the relationship between PrxⅡ and the prognosis and the development of gastric cancer. Methods: The expression of PrxⅡmRNA and protein in gastric cancer tissues and the paired adjacent normal tissues from 45 patients was detected by real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) and Western blot. The same methods were used to detect the expression of PrxⅡ mRNA and protein in GES-1, MGC-803, MKN-45 and MKN-28. Tissue mi-croarray and immunohistochemistry were used to detect the expression of PrxⅡ protein in gastric cancer tissues and the paired adjacent normal tissues from 116 patients. The relationship between the results and clinicopathological char-acteristics was analyzed. The prognosis was analyzed. Results: According to results of RTFQ-PCR and Western blot, we found that PrxⅡ mRNA and protein in gastric cancer tissues were significantly higher than that in adjacent normal tissues (P<0.05). PrxⅡ mRNA and protein in gastric cancer cells were higher than that in normal gastric cells (P<0.01).Immunohistochemistry revealed that the expression of PrxⅡ protein in gastric cancer tissues (76.7％) was also significantly higher (P<0.01) than that in adjacent normal tissues (30.1％). The expression of PrxⅡ protein is significantly related to tumor size, histological differentiation, depth of invasion, TNM stage and lymph node metastasis (P<0.05), but had no significant relationship with the gender, age, tumor location and distant metastasis. Survival in patients with higher PrxⅡ expression significantly shorter than in those with lower expression (P<0.01). PrxⅡ is an independent prognostic factor of gastric cancer (P<0.05). Conclusion: PrxⅡ promotes the development of gastric cancer. It is one of the adverse prognostic factors of gastric cancer and may serve as a new therapeutic target for gastric cancer.

Objective To explore the expression of Ras-related protein 11(Rab11)in hypoxia, the effect of Rab11 on the invasion and migration of cervical cancer cell line SiHa and its possible mechanism. Methods SiHa cells were divided into 4 groups, the normoxic blank group (normal culture in normoxia), the hypoxic blank group (normal culture in hypoxia), the negative control group [transfection of negative control small interfering RNA(siRNA)in hypoxia], the Rab11-siRNA group (transfection of Rab11 siRNA in hypoxia). Western blot was used to examine the expression of Rab11, integrin α5, integrin β3, phosphorylated focal adhesion kinase(p-FAK), phosphorylated phosphatidylinositol 3 kinase(p-PI3K) protein, together with the expression of Ras correlative C3 creotoxin substrate 1(Rac1), which was critical in regulating cell invasion. The mRNA expression of Rab11 in the 4 groups was detected by realtime-qPCR. The cell invasion was detected by matrigel assay, while the cell migration was detected by transwell assay. Immunofluorescence was used to identify intracellular location of Rac1 in SiHa cell. Results (1) The expression of Rab11, intergrin α5, intergrin β3, p-FAK, p-PI3K and Rac1 in the normoxic blank group were 0.56±0.04, 0.33±0.03, 0.32±0.03, 0.36±0.03, 0.35±0.03 and 0.47±0.03, respectively. In the hypoxic blank group, they were 0.73±0.03, 0.74±0.03, 0.61±0.03, 0.62±0.03, 0.60±0.03 and 0.73±0.03, respectively. In the negative control group, their expressions were 0.72±0.03, 0.73±0.03, 0.59±0.03, 0.61±0.03, 0.59±0.03 and 0.72±0.03, respectively. While in the Rab11-siRNA group, they were 0.44±0.03, 0.30±0.03, 0.29±0.03, 0.30±0.03, 0.30±0.03 and 0.34±0.04, respectively. The expressions of Rab11, α5, β3, p-FAK, p-PI3K and Rac1 were significantly higher in the hypoxic blank group than in the normoxic blank group(P<0.05), and were significantly lower in the Rab11-siRNA group than in the hypoxic blank group and the negative control group(P<0.05). (2) The expressions of Rab11-mRNA were 1.000±0.000, 1.454±0.114, 1.442±0.101, 0.570± 0.046 in the normoxic blank group, the hypoxic blank group, the negative control group and the Rab11- siRNA group, respectively. It was significantly higher in the hypoxic blank group than in the normoxic blank group(P<0.05), and was significantly lower in the Rab11-siRNA group than in the hypoxic blank group and the negative control group(P<0.05). (3) By Matrigel, the invasion cell number in the normoxic blank group, the hypoxic blank group,the negative control group and the Rab11-siRNA group were 65±12, 106±16, 104± 17 and 50±11, respectively. The invasion capacity was significantly higher in the hypoxic blank group than in the normoxic blank group(P<0.05), and was significantly lower in the Rab11- siRNA group than in the hypoxic blank group and the negative control group(P<0.05). (4) By transwell assay, the migration cells in the normoxic blank group, the hypoxic blank group, the negative control group and the Rab11-siRNA group were 127±12, 169±15, 161±13 and 77±13, respectively. The capacity of invasion was significantly higher in the hypoxic blank group than in the normoxic blank group(P<0.05), and was significantly lower in the Rab11- siRNA group than in the hypoxic blank group and the negative control group(P<0.05). (5) The immunofluorescence showed that the red fluorescence intensity around nucleus was significantly increased in the normoxic blank group, the hypoxic blank group and the negative control group than in the Rab11- siRNA group. Conclusions Hypoxia could promote the invasion and migration of SiHa cells. In hypoxia, the down regulation of Rab11 expression could inhibit the invasion and migration of SiHa cells. This might be due to the decreased expression of the intergrin α5, intergrin β3, p-FAK, p-PI3K and Rac1 protein.