The Expression And Significance Of HMGA2 In Esophageal Squamous Cell Carcinoma

BackgroundEsophageal carcinoma is one of the common malignant tumors in our country and in the world with a high mortality and a high morbidity. Esophageal squamous cell carcinoma(ESCC) and esophageal adenocarcinoma(ECA) are the two main pathological types.Esophageal squamous cell carcinoma accounts for approximately 90% of esophageal cancer in China,which is severely harmful to people health.However, the early diagnosis of ESCC is extremely difficult and the overall five-year survival rate remains unsatisfactory.With the advance of scientist and development of society, molecular targeted therapies display its advantage in the therapy of malignant tumors.For example,the application of sorafenib and gefitinib can greatly improve the prognosis of the patients.Hence it is of great significance for the treatment of ESCC to screen the biological markers and to clarify the relative signaling pathways.High mobility group AT-hook2(HMGA2) is a non-histone chromosomal protein.lt contains three AT-hook basic domains conferring it the ability to bind the DNA,known as "architectural transcription factor".HMGA2 is highly expressed during embryogenesis,whereas the expression is barely detectable in normal adult tissues.Recent studies found aberrant expression of HMGA2 in various tumors such as breast cancer,pancreatic cancer,gastric cancer and hepatic cancer,and up-regulation of HMGA2 was correlated with the staging and prognosis of malignant tumors.So far, there has been no system report on the expression and significance of HMGA2 in patients with ESCC.This study was designed to investigate the correlation between HMGA2 overexpression in ESCC tissues and prognosis in patients with middle thoracic ESCC after Ivor-Lewis esophagectomy.Moreover,lentivirus carrying the HMGA2shRNA was used to transfected esophageal squamous cancer cells Eca109 to explore the effect of HMGA2 gene silence on tumor proliferation and invasion.Part I:The relationship between the HMGA2 overexpression and the clinicopathological characters in patients with ESCCObjective:To investigate the expression of HMGA2 in ESCC tissues and the link between HMGA2 overexpression and the clinicopathological characters in patients with ESCC.Methods:According to the inclusion criteria,127 patients were recruited in this trail.We obtained ESCC tissue and corresponding healthy esophageal mucosa(CHEM) tissue from surgical specimen of each selected patients.HMGA2 expression levels were validated by immunohistochemistry and western blot analyses. SPSS 19.0 statistical software was used to perform all statistical analyses.The correlation between HMGA2 expression and pathological parameters was determined by the chi-square test.Results:There were 72 cases with HMGA2 high expression and 55 cases with HMGA2 low expression in the ESCC tissues.The expression of HMGA2 was correlated with histological differentiation(P=0.008),tumor status(P=0.007),lymph node metastasis status(P<0.001) and the TNM stage of tumors(P=0.006).Conclusions:HMGA2 protein overexpression was significantly correlated with tumor status,lymph node metastasis status, histological differentiation and the TNM stage of tumors.Overexpression of HMGA2 may play an important role in the infiltration and development of ESCC.Part II:The relationship between the HMGA2 overexpression and the prognosis in patients with ESCCObjective:To investigate the relationship between the HMGA2 overexpression and the prognosis in patients with ESCC after radical resection via Ivor-Lewis esophagectomy.Methods:Patients who were recruited in this trail were examined regularly every 3-6 months after Ivor-Lewis esophagectomy.All statistical analyses were performed with SPSS 19.0 statistical software. We calculated the survival rate by the Kaplan-Meier method and the log-rank test was performed to compare the survival difference.The independent prognostic factors were judged by means of Cox regression multivariate analysis.Results:The five-year overall survival rate was 19.69%. Patients with HMGA2 protein overexpression had a five-year survival rate of 13.89% compared to 27.27% of those without HMGA2 protein overexpression.The results of multivariate analysis indicated that clinical stage of tumors,histological differentiation degree and HMGA2 protein overexpression were independent prognostic factors.Conclusions:Clinical stage of tumors,histological differentiation degree and HMGA2 protein expression were independent prognostic factors.Part ?:Role of HMGA2 in proliferation and invasion of ESCC cell line Eca10O9Objective:To explore the role of HMGA2 in proliferation and invasion of ESCC cell line Eca109.Methods:Silencing of HMGA2 ESCC cell line were abtained by transfected of lentivirus containing specific shRNA targeted to HMGA2.Transwell assay was performed to explore the invasion ability of ESCC cells and CCK-8 assay was performed to explore the proliferation ability of ESCC cells.Results:The proliferation suppressing effects of RNAi targeted to HMGA2 were observed by CCK-8 assay. Invasion ability of Eca109 cell line transfected with lentivirus-mediated shRNA targeting HMGA2 was significantly inhibited.Conclusions:After stable silencing of HMGA2 expression in Eca109,cell proliferation and invasion abilities were decreased in vitro.