Molecular Mechanism Of Amplication Of ACK1 On Gastric Cancer Tumorigenesis And Metastasis And Its Application In Clinical Prognosis

Background and significance: Gastric cancer is one of the most common malignant tumors worldwide. Although surgical resection is still considered the primary strategy for treating GC patients, the prognosis of patients with GC remains poor as most cases are confirmed at advanced stages and distant metastasis due to a lack of early stage symptoms. Targeted small molecule or antibody to inhibit a specific addictive oncogene are promising therapeutic strategy. Therefore, there is an urgent need for identifying novel key targets within GC metastasis and tumorigenesis, following by discovering more new therapeutic targets. Previous studies implicated the activated Cdc42-associated kinase 1(ACK1) gene may amplify in gastric cancer(GC), suggesting that closely related with GC progression. Hence, our study mainly focused on the clinical roles and molecular mechanisms of ACK1 abnormalities in GCMethods and results: 1. Significantly higher ACK1 DNA copy numbers and the m RNA levels of ACK1 in Gastric cancer tissues were observed by analyzing the Oncomine database. 2.Using the extensive tissue microarray to investigate the correlation of ACK1 level with prognosis. We found ACK1 was up-regulated in GC tissues, which was correlated with a poor prognosis in patients with GC. 3.The methods, such as Transwell chamber and Flow cytometry were applied to measure the effects of si ACK1 or over expression ACK1 on gastric cell proliferation、 cell cycle、cell apoptosis、EMT、cell migration and invasion. Over expression of ACK1 promoted gastric cell EMT、migration and invasion. Silencing of ACK1 inhibited gastric cell proliferation、colony formation、EMT、migration and invasion. Silencing of ACK1 induced gastric cell G2/M arrest and apoptosis. 4.The xenograft tumor mouse model and lung metastasis model were using to investigate the functions of ACK1 in GC. Stable silence of ACK1 inhibited gastric cell tumorigenesis and metastasis in vivo. 5.ECD was demonstrated to be a key downstream effector of ACK1 in the regulation of gastric cell proliferation、colony formation、EMT、migration and invasion by using Transwell、Flow cytometry、si RNA and other methods. 6.Using Luciferase, Ch IP, si RNA and other methods. We demonstrated that the mechanism of ACK1 promoted gastric cell tumorigenesis and metastasis through the AKT-POU2F1-ECD signaling axis in GC cells. 7.We demonstrated the mechanism of ACK1 promoted the tumor suppressor p53 protein ubiquitination in an ECD-dependent manner.Conclusion: 1.ACK1 gene was amplication in GC cells and the up-regulated ACK1 was correlated with a poor prognosis in patients with GC 2.We demonstrated ACK1 promotes gastric cancer cell proliferation、colony formation、EMT and metastasis. 3.We revealed the mechanism of ACK1 promotes gastric cell tumorigenesis and metastasis by activating AKT-POU2F1-ECD signaling in GC cells. 4.We demonstrated the mechanism of ACK1 promotes the tumor suppressor p53 protein ubiquitination in an ECD-dependent manner.