| Liver cancer cells in vitro two-dimensional cultivation have an obvious phenomenon of loss of contact inhibition, which is the outstanding performance for the proliferation of malignant cells. Contact inhibition of cell growth is a result of interaction between social behavior, and goes beyond a single cell line,groups linked to the cytoskeleton network system. Cell social behaviour and its regulation closely relate. A skeleton structure has a direct role in the regulation and control. Cytoskeleton structure of tumor cells owns shortcomings and results in the loss of contact inhibit. Through mechanical means loading the growth substrate of liver cancer cell to stimulate the stretch, this experiment controls pre-tension in the cytoskeleton. These research findings have a certain sense for contact inhibition loss.Object Through researching the distribution and expression of E-cadherin, cell movement and cytoskeleton in the liver cells and liver cancer cells, we explore the loss of contact inhibition mechanism.Methods With microscopic morphology, image analysis software, immune staining, confocal laser microscopy techniques, we respectively dectect morphological characteristics, cytoskeleton deformation ability and E-cadherin expression and distribution in different growth density of liver cancer cells and liver cells . The cell synchronization, MTT, FACS and other experimental technologies were used in testing cell growth condition.Result 1) With liver cells(LO2) and liver cancer cell(HepG2) growth density of 102,104, E-cadherin expression of the average (77.43±5.77,76.06±5.61)in HepG2 was significantly higher than that of LO2 (15.81±2.23,16.96±1.12), p <0.05; E-cadherin distribution: LO2's E-cadherin were scattered along point-like distribution in cell membrane, HepG2 showed a diffusion-like distribution. Migration movements of the two states (102,104) had no significant difference; LO2 and HepG2 growth curve is similar;2) Under 106 growth density, HepG2's E-cadherin (53.89±3.31) is still higher than the expression of LO2's (28.23±1.23). E-cadherin expression in two different cell region presented significant difference: E-cadherin expression in LO2's contact region was 28.94±1.15, HepG2's was 19.32±7.17, p <0.05. LO2's E-cadherin distribution in the adjacent cell surface was to gather, rather than on surface in HepG2's. LO2 inhibited movement in106, but HepG2 continued deformation and movement;3) With LO2 and HepG2 in 106 ,E-cadherin expression had adjustments in contact regions: the average level of LO2 decreased slightly, but the contact area was increased to 36.49±1.29, HepG2's E-Cadherin levels were significantly decreased to an average of 28.58±2.72, but no significant change in contact (22.87±2.08); E-cadherin distribution: in LO2 the E-cadherin furtherly gathered to the contact area, showing a small gathering light point, HepG2's E-cadherin in the adjacent cell surface had no significant differences, and remained on the surface. At this time we continued culture LO2 and HepG2 for 48 hours, LO2 would appear round or oval-shaped "empty hole", HepG2 would heap circular cells. Using Confocal laser scanning microscope showed three-dimensional nuclear shape, found significant deformation of LO2, but HepG2 still showed circular or elliptical;4) With sretching and contracting basement of contacted HepG2, the rate 10%, 30%, 50%, experiments showed that above 70% cells significantly (p <0.05) were along the loading direction, after 6 h become random orientation; stretching10% S owned a period of 26.85±1.32%, the control group was 31.91±1.13%, non-significant difference; contracting 10% S owned a period 29.24±2.17%, the control group was 30.33±2.67%, no significant difference. Changes in the cell cycle phase weren't significantly, p> 0.05; gradually loaded with tension and contraction increased the proportion of apoptosis.Conclusion 1) Growth density of LO2 was positively correlated with E-cadherin distribution, and was negatively correlated with the cell movement, deformation and proliferation ability;2) Growth density of HepG2 partly impacted on E-cadherin distribution, but didn't obviously impact on cell movement, deformation and proliferation;3) For mechanical stimulating HepG2's response was not obvious, but the anti-injury ability was noticeable.
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