Clinical Significance And Related Molecular Mechanism Research Of CHKA Expression In Lung Adenocarcinoma

Backgroud and PurposeIn recent years, the lung cancer has become the most common therioma. Although understanding of lung cancer has been a certain development and progress, but the death rate of lung cancer in the world is a significantly increasing. Due to smoking and environmental factors, lung adenocarcinoma becomes the most pathological types of the lung cancer and primary death cause in male therioma .The pathogenesis of lung adenocarcinoma is involved in multiple genes. Most lung adenocarcinoma patients are not died from tumor, but from tumor recurrence and metastasis. To further study the molecular mechanism of the development and metastasis of lung adenocarcinoma, and to analyze the prognostic factors, have important clinical significance. Due to the mechanism of lung cancer is not clear, the treatment of whom is lack of specificity.Choline kinase is the first key enzyme in the organism cell, which can catalysis choline to choline phosphate and finally synthesis bilayer lipid membrane. The enzyme is encoded by the choline kinase a (CHKA) and the choline kinase P (CHKB) two genes, and the two forms an active choline kinase by the same two or two different forms.Previous related studies mainly focused on the function of the enzyme in lipid metabolism,among them Choline kinase a is the enzyme which catalysis choline into phosphatidylcholine, who's effect on human tumors has been extensively studied.As an important enzyme, CHKA plays an important role in the activation of major growth factors, such as Ras signaling pathway, which plays a role in the activation of some human tumor cells and tissues. A lot of researches on the tumor cells indicated that the expression and activity of CHKA not only directly related with tumor cell proliferation, but also closely related with the degree of malignancy and metastasis, which make it a molecular marker for predicting the prognosis of hepatocellular carcinoma and cervical cancer and to be a potential target for cancer therapy too.Transformation of Epithelial mesenchymal (Epithelial mesenchymal Transition, EMT) was first put forward in 1982, refers to the epithelial cell differentiate to the mesenchymal cell through a series of changes in the specific physiological and pathological situations, the phenomenon of differentiation embodied in epithelial cells'polarity loss and obtain mesenchymal phenotype, the ability of connections and adhesion between cells may decline or disappear, the ability of migration and metastasis were increased, the change of cells' morphological as well as cell marker expression level, reduce the epithelial markers such as ?-catenin and E-cadherin, increase the interstitial phenotypic markers such as vimentin?N-cadherin and SMA. EMT playsan important role in embryonic development, exists in the pathogenesis of many chronic diseases and the tissue of invasion and metastasis process. The molecular regulation mechanisms of cell EMT occur is more complex and involves multiple cellular signal transduction pathways, there were many main pathway were reported currently,such as dTGF-BMP pathway? PI3-K/Akt pathway?Wnt/?-cateninpathway?Srcpathway and Integrin pathways. However, the key genes and their mechanism of transduction which induced EMT and regulated related pathways key were unclear.In recent years,many studies resulted that choline kinase and its catalytic product phosphorylcholine was highly expressed in a variety of tumors which included breast cancer, lung cancer, colon cancer, bladder cancer, prostate cancer and ovarian cancer, found that the expression level of CHKA correlated with clinical outcome in breast cancer,liver cancer and bladder cancer patients, confirmed CHKA had cancer genetic characteristics, and being involved in the development of malignant tumors, affecting prognosis. However, how is expressed in lung cancer, whether to participate in the malignant progression of lung cancer, the relationship with clinicopathological characteristics of lung cancer among CHKA is nuclear. As an important proto-oncogene, however, the relevant CHKA role in lung adenocarcinoma occurrence and development is no reported. Our team of preliminary experiment resulted suggestion of CHKA is closely related to the malignant biological phenotype of lung cancer, however there was no report the relationship between CHKA and the prognosis of lung adenocarcinoma, whether CHKA affect the EMT of lung epithelial cells has never been discussed. Therefore, this study mainly focus on CHKA expression in lung adenocarcinoma and its clinical significance, further explores its biological function and the related molecular mechanism with poor prognosis of lung cancer.Part I:Clinical Research on the Role of CHKA Expression in Prognostic Prediction of Lung AdenocarcinomaBackground and Object:Lung cancer has become the world's most common malignant tumor, which is a serious threat to human health. The morbidity and mortality of lung cancer are very high, which is owing to its unclear pathogenesis and lack of effective means of early diagnosis and prevention. The majority of lung cancer patients are not died of the primary tumor, but died of the recurrence and metastasis of tumor. It has important clinical significance to study the molecular mechanism of lung cancer development and metastasis, and analyze its prognostic factors to clarify the potential target. Choline kinase a (CHKA), the enzyme that converts choline to phosphocholine, has been studied in human carcinogenesis widely. CHKA plays an important role in cancer gene mediated transformation and in the formation of a variety of human tumors, such as lung cancer. Until now, the expression and underlying clinical pathological characters of CHKA in lung adenocarcinoma remains elusive.Methods:1. To detect CHKA expression in lung adenocarcinoma tissue and corresponding cancer adjacent tissue by immfunohistochemistry, RT-PCR, Western-Blot.2. Using statistical methods to analyze the relationship between the expression of CHKA and the clinicopathological features, prognosis and survival of patients.Results:1. The gene copy number and mRNA expression in lung adenocarcinoma tissues were significantly higher than that in the adjacent tissues.2. In lung adenocarcinoma tissue, the CHKA protein was highly expressed, which was significantly higher than that in the adjacent tissues.3. The high expression of CHKA in adenocarnoma was associated with tumor microvascular invasion, stage and differentiation status and low survival time.Conclusions:1. The expression of CHKA was higher in lung adenocarcinoma than that in the adjacent tissues.2. The high expression of CHKA was closely related to the poor prognosis of patients with lung adenocarcinoma.3. The increased expression of CHKA was associated with some clinicopathological features, such as tumor dimeter,stage and differentiation status.4. The overall survival time of patients with high expression of CHKA was shorter, and the tumor recurrence was earlier.5. CHKA is expected to be a molecular marker for predicting the prognosis of lung adenocarcinoma.Part ?:Mechanism Research on the Role of CHKA Expression in Prognostic Prediction of Lung AdenocarcinomaBackground and Object:Looking for early diagnosis and prognostic indicators is major problem in the basic and clinical research of lung adenocarcinoma, and is also the main step in the research on prevention and treatment of lung adenocarcinoma. CHKA can induce normal cell transformation to form tumor cells in the human body, and CHKA specific inhibitors have been shown to have anti proliferation activity in vitro and anti-tumor activity in vivo. Epithelial mesenchymal transition (EMT) is a cellular phenotype conversion process, in which the cellular phenotype is converted from polarity phenotype of epithelial cells into mesenchymal phenotype. The cell adhesion force decreases, the invasion and migration ability of cells increases. We previously found that the CHKA was expected to become the prognosis of patients with lung adenocarcinoma prediction of molecular markers, while its role in molecular mechanism was unclear. This study is to observe the role of CHKA in EMT of lung cancer cells and its role on migration and invasion of lung cancer cells in vitro, and to further explore the molecular mechanisms of CHKA expression in the role of prognostic prediction in lung adenocarcinoma.Methods:1.To detect CHKA expression in lung cancer cells by RT-PCR? western-blot.2.Lenti-virus was used to infection and establish CHKA interference lung adenocarcinoma cancer cell line and their control cell line.3. Then shCHKA cell line and its control cell line were futher used to observating wear proliferation assay and invasion assay.Results:1. Overexpression of CHKA promoted the migration and invasion ability of lung adenocarcinoma cells.2. The overexpression of CHKA can induce the EMT of lung adenocarcinoma cells.3. Down-regulation of CHKA effectively inhibited the migration and the invasion ability of lung adenocarcinoma cells.4. Overexpression of CHKA activated PI3K/Akt signal pathway, and interference of CHKA inhibited the transduction of PI3K/Akt signal pathway.5. Also, the inhibition of PI3K/Akt pathway obviously reduced the migration and invasion ability of lung adenocarcinoma cells mediated by CHKA.Conclusions:1. The overexpression of CHKA can induce the EMT and promoted the migration and invasion ability of lung adenocarcinoma cells.2. The effect of CHKA on cell migration and invasion of lung adenocarcinoma may be mediated by PI3K/Akt signaling pathway.