Mechanism Of Invasion,Migration And EMT Mediated By LSD1-mediated Wnt Pathway In Gastric Cancer Cells

Histone Lysine Specific Demethylase 1(referred to as LSD1)is the first group of flavin adenine dinucleotide(referred to as FAD)-dependent lysine-specific histone demethylase which was found by Professor Shi Yang in 2004.The group also confirmed that the demethylase in a variety of cancer cells was highly expressed.Wnt3 a,an important cytokine secreted by cells,can bind to the Wnt ligand on the cell membrane and activate the classical signal Wnt pathway.This study was to investigate the effect of LSD1 on Wnt signaling pathway by analyzing the correlation between LSD1 and Wnt3 a in gastric cancer tissue sections 1)The correlation between the expression of LSD1 and Wnt3 a in gastric cancer tissuesLSD1 has been reported highly expressed in the prostate cancer,breast cancer,lung cancer,neuroblastoma and other malignant tumors.The expression of LSD1 in the undifferentiated gastric cancer cell line HGC-27 and poorly differentiated gastric cancer cell line MGC-803 was found to be much higher than that in normal gastric epithelial cell GES-1.The previouse study have shown that the key Wnt3 a protein of Wnt classical pathway could be influenced by the expression of LSD1 in gastric cancer cell line MGC-803.This topic aimed to further explore the correlation between LSD1 and Wnt3 a.The expression of LSD1 and Wnt3 a in tumor cells were detected by immunohistochemistry using the specific antibody of LSD1 and Wnt3 a respectively.Finally,the correlation between the LSD1 and Wnt3a was analyzed by Spearman test.The results showed that there was a relationship among the protein expression of LSD1 and Wnt3 a expression in gastric cancer patients,and that the correlation between LSD1 and Wnt3 a expression was positively ralative.2)The mechanism of LSD1 affecting Wnt3 a secretion in gastric cancer cellsPrevious studies have shown that there is a significant correlation between the expression of LSD1 and Wnt3 a in gastric cancer patients.On this basis,this chapter was to further investigate whether there was a regulation between LSD1 and Wnt3 a in gastric cancer cells and gastric mucosal epithelial cells,in order to study the relationship between LSD1 and Wnt pathway.The constructed lentivirus pLVX-shRNA-LSD1 was first transfected into gastric cancer cells MGC-803,HGC-27,SGC-7901 and gastric epithelial cells GES-1 using transfection reagent liposome 3000.From the results of Elisa,after downregulation of LSD1,the expression of Wnt3 a in cell suspension was down-regulated in MGC-803,HGC-27 and SGC-7901 cells,and almost not changed in gastric mucosa epithelium cell GES-1.The mRNA expression of PORCN protein was detected by qPCR assay and the data showed that after downregulation of LSD1,the mRNA expression of PORCN protein was significantly down-regulated in gastric cancer cells HGC-27,MGC-803 and SGC-7901,and almoet not changed in GES-1 cells.The results indicated that LSD1 affects the secretion of Wnt3 a in gastric cancer cell via regulating the transcription of PORCN.3)LSD1 affects the invasion and metastasis of gastric cancer cells through the Wnt pathwayPrevious studies have shown that upregulation of LSD1 expression in gastric cancer cells promotes cell invasion and migration,as well as the EMT process.Studies have found that Wnt pathway is essential for tumor cell proliferation,migration and differentiation.This chapter was to further investigate whether LSD1 was involved in cell invasion,migration and EMT process of gastric cancer cells mediated by Wnt pathway.The pIRES-LSD1 plasmid was used to overexpress LSD1 in MGC-803 and SGC-7901 cells.After confirming the overexpression of LSD1,PORCN inhibitor Wnt C59 was added to LSD1 overexpressing cells,and the migration and invasion ability of the cells were detected by Transwell and Wound Healing assay.The results demonstrated that overexpression of LSD1 promoted the migration and invasion of LSD1 overexpressing cells,and the promotion was offset by Wnt-C59.The levels of E-cadherin and N-cadherin in MGC-803 cells and SGC-7901 cells was detected by Western Blot assay,and we found that LSD1 overexpression significantly decreased the expreesion of E-cadherin and increased the expression of N-cadherin,while the expression of E-cadherin and N-cadherin was almost not changed after treatment with WntC59.Taken together,LSD1 may regulate the gastric cancer cell migration,invasion and EMT process through Wnt pathway.