Decreased TIP30Expression Promotes Tumor Growth And Metastasis In PDAC

Backgroud and objective: TIP30,also called CC3,is a tumor suppressor withpro-apoptotic and anti-metastasis properties.It was originally identified by a differentialdisplay analysis of messenger RNA from the highly metastatic human variant small celllung cancer (v-SCLC) versus less metastatic classic small cell lung cancer (c-SCLC) celllines.The expression of TIP30has been detected in many human normal tissues and wasdown-regulated in certain tumor cells such as melanoma,breast cancer,neuroblastoma,glioblastoma.Recently,many digestive system neoplasms,such as gallbladder cancer,colorectal cancer,gastric cancers and hepatocellular carcinoma,all have been reported withdown-regulated TIP30expression.TIP30was considered to have tumor suppressor activityby inhibiting tumor growth,invasion and angiogenesis and inducing apoptosis.TIP30mutants not only abrogated the tumor suppressor potential but also gained oncogenicactivities.Pancreatic ductal adenocarcinoma (PDAC) is known for its aggressive growth.characterised by early tissue invasion and metastasis,but there is no report about TIP30expression in PDAC.Our previous study had proved different PDAC cell lines showeddifferent expression of TIP30with different invasion and matastasis potentials.In this study,we aimed to first examine the expression of TIP30in PDAC and to obtain further insightinto the mechanism of whether TIP30induced EMT in pancreatic cancer.Methods: The expression of TIP30was analysed in106PDAC patients and comparedwith the clinicopathological features of the patients. TIP30expression levels wereexamined by real-time RT-PCR and Westernblotting analyses.Tumorigenicity potentials ofPDAC cells were studied in vitro and in nude mice.Apoptosis were examined by AnnexinV-FITC kit.Wound-healing and Matrigel invasion assays were used to determine migrationand invasion potentials of PDAC cells.RT-PCR,westernblotting and immunofluorscencewere used to analysis EMT.RNA interference mediated gene silence were used to inhibitthe expression of Snail and Slug.Results: The expression of TIP30was analysed in106PDAC patients and compared withthe clinicopathological features of the patients.The expression of TIP30was correlatedwith lymph node metastasis(P <0.05) and Ki-67stain (P <0.05) in PDAC patients.Theresult of Kaplan–Meier analysis and Cox proportional hazards regression modelinganalysis show TIP30expression independently predicted better survival inpancreaticoduodenectomy patients(p <0.01),while TIP30expression was associated withE-cadherin expressionin (p <0.01).Then we suppressed the protein expression of TIP30in three primary PDAC cell lines with profoundly different E-cadherin expressions.Moreinvasion were found in all three cell lines in vitro,but different EMT-related genealterations had been found in different cell lines,suppressing TIP30upregulated Snail inSW1990and Capan-2cell lines,then downregulated E-cadherin.However,in PANC-1cellline,suppressing TIP30upregulate Slug instead Snail,then upregulated MMP9rather thanE-cadherin.SiRNA ensured these result.Conclusion: Our results demonstrate that TIP30genes are frequently down-regulated inPDAC patients, and loss of tumoral TIP30expression is an independent predictor of pooroutcome,while TIP30enhances invasion and metastasis of pancreatic cancer cells throughupregulation of E-cadherin or MMP9in different PDAC cell lines,In these processes,Snailand Slug are the key regulators.These findings provide new insight into the molecularmechanisms leading to matastasis of PDAC and may have potential therapeuticapplications.