Knockdown of long noncoding RNA CCAT1 inhibits cell growth, invasion and peritoneal metastasis via downregulation of Bmi-1 in gastric cancer.

Long noncoding RNA colon cancer-associated transcript 1 (lncRNA CCAT1) is highly expressed in gastric cancer (GC) tissues compared with normal counterparts and CCAT1 upregulation can promote proliferation and migration of GC cells in vitro. B-cell specific moloney leukemia virus insertion site 1 (Bmi-1) expression is positively correlated with tumor progression. The present study aimed to investigate the biological functions of CCAT1 and the relationships between CCAT1 and Bmi-1 in GC progression. In the present study, CCAT1 was knocked down by specific shRNA transfection in two human GC cell lines (MGC-803 and SGC-7901). The effects of CCAT1 knockdown on GC cell proliferation, cell cycle, migration and invasion were investigated in vitro. The effect of CCAT1 knockdown on peritoneal metastasis was assessed in nude mice. Bmi-1 expression levels were examined both in vitro and in vivo. The results showed that CCAT1 knockdown markedly inhibited cell proliferation, migration and invasion, arrested the cell cycle at G0/G1 phase in vitro, and inhibited peritoneal metastasis in nude mice, along with the downregulation of Bmi-1. Taken together, CCAT1 is functionally involved in growth and metastasis of GC cells and it may be a potential target for GC therapy.

[Factors influencing survival of patients with pancreatic adenocarcinoma after surgical resection].

Objective: To investigate the clinical outcomes and prognostic factors in patients with pancreatic cancer after surgical resection with curative intent and analyze factors affecting 2-year and 5-year survival of patients. Methods: A total of 469 patients with pancreatic adenocarcinoma undergoing curative resection were included in the study, and the clinical data of these patients were analyzed retrospectively. Univariate and multivariate analyses were performed to examine factors affecting prognosis of these patients. The clinicopathological characteristics of patients who survived for ≤2 years and >2 years as well as ≤5 years and >5 years were compared, respectively. Results: The multivariate analysis showed that lymphovascular invasion (P=0.024), lymph node metastasis (P<0.001), vascular resection (P=0.002), maximum tumor diameter >2 cm (P=0.009), poor differentiation (P<0.001) were negative prognosis factors, but postoperative chemotherapy (P<0.001) was an independent positive prognostic factor. Comparison of the patients who survived for ≤2 years and >2 years showed that lymphovascular invasion (P=0.012), lymph node metastasis (P<0.001), vascular resection (P=0.014), maximum tumor diameter>2 cm (P=0.004), poor differentiation (P<0.001), peri-pancreatic fat invasion (P=0.005), absence of postoperative chemotherapy (P<0.001), advanced tumour, node and metastasis (TNM stage) (P<0.001) were associated with 2-year survival. With regard to 5-year survival, lymph node metastasis (P=0.005), poor differentiation (P=0.014) and TNM stage(P=0.025) were associated with it. Conclusions: Our results suggest that lymphovascular invasion, lymph node metastasis, vascular resection, maximum tumor diameter >2 cm, poor differentiation and absence of postoperative chemotherapy were independent negative prognostic factors. Lymph vascular invasion, lymph node metastasis, vascular resection, maximum tumor diameter >2 cm, poor differentiation, peri-pancreatic fat invasion, absence of postoperative chemotherapy, advanced TNM stage were associated with 2-year survival, and lymph node metastasis, degree of differentiation and TNM stage are important prognosis factors affecting long-term survival of patients.