Cancer-associated E239K Mutation Of LSD1 Promotes The Migration And Invasion Of Luminal A Breast Cancer Cells By Reducing The Expression Of ERα

Backgroud: Breast cancer has become one of the main causes of death in women.The causes of its occurrence and development include genetic changes and abnormal epigenetic regulation.Histone lysine demethylase LSD1 is the first histone lysine specific demethylase to be identified,which catalyzes the removal of monomethylation and dimethylation of H3K4 and H3K9,thereby inhibiting or activating gene transcription.Breast cancer can be divided into several subtypes,and epithelial-mesenchymal transformation plays an important role in the metastasis of breast cancer.LSD1 plays a role as a tumor suppressor in Luminal breast cancer.In the process of epithelial-mesenchymal transformation,cells in the original epithelial state change their cell morphology and skeleton structure and begin to have more invasion and migration characteristics,which is a key step in the occurrence and development of cancer.Estrogen signaling and estrogen receptor(ER)play a key role in the occurrence and development of breast cancer.Most breast cancers are estrogen-dependent,and the destruction of ER function is the main therapeutic strategy for targeting this disease.Objective: We systematically investigated the effects of LSD1 E239 K mutation on the invasion and metastasis of MCF7 in Luminal A breast cancer cells and its molecular mechanism.Method: By means of lentivirus infection,LSD1 gene knockout was performed in Luminal A breast cancer cell MCF7 cells,and the wild-type LSD1 and mutant LSD1 E239 K were supplemented to construct cell lines with stable knockout or complement of LSD1.The influence of LSD1 E239 K mutation on LSD1 function and on epithelial-mesenchymal transformation was explored through the expression of cell morphology and key target genes.The influence of LSD1 E239 K mutation on more cancer-related genes and pathways was further explored through transcriptome sequencing.Chromatin immunoprecipitation and other experiments were used to further clarify the molecular mechanism of LSD1 E239 K mutation in regulating Luminal A breast cancer cellsResults: We first observed that the E239 K mutation of LSD1 changed the cell morphology from epithelial cell morphology to mesenchymal cell morphology.The results of Transwell chamber and cell scratch assay showed that the E239 K mutation of LSD1 promoted the invasion and migration of Luminal A breast cancer cells.Next,LSD1 E239 K mutation was verified to increase the expression and transcription levels of invasion and migration related proteins,such as Slug and Vimentin,etc.The results of RNA-seq analysis showed that LSD1 E239 K mutation affected a group of key genes involved in breast or cancer development,including cell-cell adhesion genes,mammary epithelial development genes,adenoid morphogenesis genes,epithelial differentiation regulation genes,and stem cell differentiation genes.More importantly,the LSD1 E239 K mutation reduced the expression of ERα,which plays a key role in invasion and migration.Chromatin co-immunoprecipitation results showed that the LSD1 E239 K mutation affected the binding of LSD1 to its target genes,and co-immunoprecipitation,GST-pull down and other experiments showed that the E239 K mutation weakened the binding of LSD1 to GATA3Conclusion: The LSD1 E239 K mutation attenuates or even eliminates the interaction between LSD1 and GATA3,and can inhibit the expression of ERα by reducing the enrichment of LSD1 gene at the ESR1 promoter.In this case,the expression of E-cadherin is further down-regulated,thus promoting the process of EMT and promoting the invasion and migration of luminal breast cancer cells.