췌장선암 정맥침범 마커로서의 TIMP1

Abstract

Background Pancreatic ductal adenocarcinoma (PDAC) is the 8th most common cancer in Korea and has a low 5-year overall survival rate (YSR) of about 12.2%. Although venous invasion is known to be the cause of poor prognosis, the precise mechanism is still unknown. In this study, we investigated biomarkers involved in venous invasion and their mechanisms using gene expression arrays and functional validation. Materials and methods Eight surgically resected formalin-fixed, paraffin-embedded (FFPE) PDAC tissues were collected. Meticulous manual microdissections for gene expression arrays were performed on the following three groups. 1) portal vein/ superior mesenteric vein with cancer cell invasion (VI); 2) pancreatic cancer without portal vein/ superior mesenteric vein invasion (CA); and 3) normal portal vein/ superior mesenteric vein tissue (NV). The candidate gene expressions were validated at protein level in 220 cases using 2D images with immunohistochemistry (IHC) and 3D images with tissue clearing and multiple immunofluorescence labeling. To identify the role of potential biomarker in venous invasion, invasion assay and western blot analysis were performed using human endothelial (EA.hy926), cancer-associated fibroblast (CAF), and pancreatic cancer (Panc1) cell lines. Results Four genes, includingTIMP1, CXCR4, OLFML2B, and CYP1B1, were specifically expressed in VI group. TIMP1 (p = 0.026) and CXCR4 protein (p < 0.001) expression in VI set were significantly higher than in CA set. Specific TIMP1 expression in venous invasive areas was found by 3D imaging. The patients with strong TIMP1-expression more commonly had lymphovascular invasion (p < 0.001) and low 5-YSR (p = 0.027) than those with weak TIMP1-expression. TIMP1 inhibition by siRNA reduced cancer cell invasion ability in the presence of CAF. TIMP1 was increased in pancreatic cancer cells along with PI3Kp110 and phospho-AKT in co-culture conditions mimicking venous invasion. Conclusions TIMP1 was a potential biomarker of venous invasion in PDAC and the TIMP1/PI3K/Akt signaling pathway may be involved. This could provide basic information for development of inhibitors to prevent venous invasion in patients with PDAC.