The Study Of Pax5 Driving The Transformation From Lung Adenocarcinoma To Neuroendocrine Carcinoma

Background: PAX5 is a member of the Pax gene family and is the only gene expressed in the hematopoietic system;in addition,PAX5 is also distributed in the central nervous system.Pax5 can play an important role in B cell development and tumor progression through gene transcriptional regulation.Studies have found that abnormal expression of Pax5 is associated with B cell malignancies,such as lymphoma and lymphocytic leukemia.Recent studies have found that the expression of Pax5 is also appeared in the non hematopoietic tumors,such as neuroblastoma,breast cancer and small cell lung cancer.It indicated that the expression of Pax5 was not only limited to B lymphocytes,but the ectopic expression of Pax5 in solid tumors may have an effect on cancer cells,and it is not clear that the occurrence and development of tumor.Aim: The objective of our work is to clarify the ectopic expression of Pax5 in solid tumors,and generated by the biological effect of cancer cells and regulatory mechanism.Our work aim to clear Pax5 and tumor metastasis correlation to determine whether it can be as a molecular target for cancer patients in chemotherapy.Explore the epigenetic mechanisms of Pax5 expression in tumor cells,and the change from neuroendocrine carcinoma to neuroendocrine carcinoma,to further understand the tumor occurrence and metastasis for regulatory networks involved,and provide information for clinical diagnosis and treatment.Methods: 1.Using RT-PCR and Western blot to detect the expression of Pax5 in different solid tumor cell lines,and immunohistochemical staining method to detect the expression of Pax5 in lung cancer tissues of patients.2.Using microarray technology,through comparison of the change of expression profile after transient Pax5,to determine which genes can be influenced by ectopic expression of Pax5 and identify cellular biological effects generated by ectopic expression of Pax5.Using cells adhesion assay,invasion experiment and over expression of Pax5 in LLC1 cells injection to C57 BL / 6 mice in vivo experiments to determine the Pax5 effect on tumor cells of the distal metastasis.3.Using tube formation assay and Sprouting assay in vitro to identify ectopic Pax5 expression has the ability to promote angiogenesis,immunofluorescence and lectin perfusion assay in vivo to verify and determine the characteristics of Pax5 to promote tumor angiogenesis and leakage.4.Using CHIP,Luciferase assay,EMSA and other molecular biological techniques to study the molecular mechanism of Pax5 regulation gene expression.Establishment of a three-dimensional continuous distribution model to determine ectopic expression of Pax5 driving the exchange from neuroendocrine carcinoma to neuroendocrine carcinoma.Result: Immunohistochemical staining experiment found that lymphocyte specific transcription factor Pax5 in lung squamous cell carcinoma,lung adenocarcinoma,adenosquamous carcinoma of the lung,bronchioloalveolar cell carcinoma and nonneuroendocrine lung large cell cancer did not express,and in small cell lung cancer and neuroendocrine large cell lung cancer ectopic expression.But using single cell RT-PCR,Pax5 is detected in a small number of lung adenocarcinoma cell transcription,and Pax5 transcription associated is elevated transcription of neuroendocrine genes related to SYN and CHGA,suggesting that Pax5 expression is associated with neuroendocrine phenotype.Pax5 ectopic expression promotes the metastasis of tumor cells in vivo,renal metastasis showed pathological character of small cell lung cancer,and the characteristics of small cell lung cancer protein(neuroendocrine factor)expression was positive.Pax5 overexpression in EGFR/CC10-rt TA double transgenic mice(classical mouse primary lung adenocarcinoma model)will alter the phenotype of lung adenocarcinoma,cancer cells scattered and small cell lung cancer characteristic protein expression is positive.Pax5 expression in lung adenocarcinoma can promote the transformation from lung adenocarcinoma to lung neuroendocrine carcinoma.Microarray analysis showed that Pax5 expression caused the up-regulation of neuroendocrine related gene expression,epidermal growth genes such as KRT-7,KRT-18,and so on is down-regulated.And John Minna laboratory on normal lung epithelial cells ? non small cell lung cancer cells and small cell lung cancer cells gene transcriptional profiling database comparison,Pax5 overexpression in human lung adenocarcinoma cell line A549 can promote A549 cell to the direction of small cell lung cancer.Ectopic expression of Pax5 promotes angiogenesis in lung cancer,and it is lack of pericyte protection.This kind of structure is not complete with high permeability,which can promote the metastasis of tumor cells.By the analysis of protein chip,overexpression of Pax5 can promote the secretion of VEGF,IL6,GM-CSF of angiogenic factor.The VEGF monoclonal antibody Bevacizumab(Avastin,approved by the FDA certified clinical antitumor drugs)treated mice can inhibit angiogenesis induced by Pax5 and improve the integrity of vascular structure,and inhibition of tumor metastasis,indicating that Pax5 by promoting angiogenesis and promoting tumor metastasis.Conclusion: Pax5 in lung adenocarcinoma cell expression promotes neuroendocrine related genes expression,making lung adenocarcinoma transformation to neuroendocrine carcinoma,promote tumor cells endowed with neuroendocrine cancer prone to metastasis;on the other hand,Pax5 and through up regulation of angiogenesis relation gene expression to promote lung cancer in structural integrity of angiogenesis,vascular leakage with hypertonic,thereby helping tumor cells into blood circulation system to distant metastasis.