Study On Micro Domain Characteristics Of Plasma Membrane Of Breast Tumor Cells By Optical Microscopy

The development,migration and invasion process of tumor cell are accompanied by the change of plasma membrane properties,and lipid rafts are dynamic,inhomogeneous,sterol-and sphingolipid-enriched domains in the plasma membrane and play an important role in cell signal transduction and membrane transport.Therefore,studying the relationship between different tumor cells and the characteristics of the lipid raft is very meaningful,which can provide a basis for many diseases that may result from the abnormal structure and function of lipid rafts.This paper studies the properties of different tumor cells and the influence of cholesterol on their characteristics by using optical microscopy and environmental sensitive probes.Firstly,the relationship between the migration ability of MCF-10A,MCF-7 and MDA-MB-231 and the generalized polarization(GP)value of these three subtypes breast cancer cells was studied by laser scanning confocal microscopy(LSCM)coupled Di-4-ANEPPDHQ probe,and the results showed that the stronger the migration ability of the cell,the higher the GP value of the plasma membrane.Secondly,cholesterol depleted reagent Methyl-?-cyclodextrin(M?CD)was used to study the effect of cholesterol on the migration ability of three cells.The experiments showed that the high cholesterol breast cancer cell MDA-MB-231 and MCF-7 were more sensitive to cholesterol deletion,and normal epithelial cells had some resistance to it.Moreover,the experimental results have also been verified by the gene expression level of cell migration marker proteins MMP-9 and uPAR.The results will help to understand the role of lipid raft in the development of cancer cells,which plays an important role in the prevention and early diagnosis of cancer.Then,the theory,simulation and experiment demonstrate the fact that the structured illumination microscopy(SIM)can improve the resolution.Next,a two-channel SIM system based on Leica inverted microscope was used to study the order phase of living cell plasma membrane by combining the environmental sensitive probe Di-4-ANEPPDHQ,the experimental results and confocal results have good consistency.Finally,the effect of cholesterol depletion on the tumor cell biophysical properties was measured by biotype atomic force microscope(AFM),and the results showed that cholesterol as an important component of lipid rafts in plasma membrane has a significant effect on cell biophysical properties.