Liver Cancer
Copyright ©The Author(s) 2002. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Apr 15, 2002; 8(2): 243-246
Published online Apr 15, 2002. doi: 10.3748/wjg.v8.i2.243
Mechanical properties of hepatocellular carcinoma cells
Gang Zhang, Mian Long, Zhe-Zhi Wu, Wei-Qun Yu
Gang Zhang, Department of Pathophysiology, The Third Military Medical University, Chongqing 400038, China
Mian Long, Zhe-Zhi Wu, Wei-Qun Yu, College of Bioengineer, Chongqing university, Chongqing 400044, China
Author contributions: All authors contributed equally to the work.
Supported by the National Science Foundation of China, No.39370198
Correspondence to: Gang Zhang, Department of Pathophysiology, The Third Military Medical University, Chongqing 400038, China.
Telephone: +86-23-68752339 Fax: +86-23-68752340
Received: August 24, 2001
Revised: September 1, 2001
Accepted: September 5, 2001
Published online: April 15, 2002

AIM: To study the viscoelastic properties of human hepatocytes and hepatocellular carcinoma (HCC) cells under cytoskeletal perturbation, and to further to study the viscoelastic properties and the adhesive properties of mouse hepatoma cells (HTC) in different cell cycle.

METHODS: Micropipette aspiration technique was adopted to measure viscoelastic coefficients and adhesion force to collagen coated surface of the cells. Three kinds of cytoskeleton perturbing agents, colchicines (Col), cytochalasin D (CD) and vinblastine (VBL), were used to treat HCC cells and hepatocytes and the effects of these treatment on cell viscoelastic coefficients were investigated. The experimental results were analyzed with a three-element standard linear solid. Further, the viscoelastic properties of HTC cells and the adhesion force of different cycle HTC cells were also investigated. The synchronous G1 and S phase cells were achieved through thymine-2-desoryriboside and colchicines sequential blockage method and thymine-2-desoryriboside blockage method respectively.

RESULTS: The elastic coefficients, but not viscous coefficient of HCC cells (K1 = 103.6 ± 12.6 N·m-2, K2 = 42.5 ± 10.4 N·m-2, μ = 4.5 ± 1.9 Pa·s), were significantly higher than the corresponding value for hepatocytes (K1 = 87.5 ± 12.1 N·m-2, K2 = 33.3 ± 10.3 N·m-2, μ = 5.9 ± 3.0 Pa·s, P < 0.01). Upon treatment with CD, the viscoelastic coefficients of both hepatocytes and HCC cells decreased consistently, with magnitudes for the decrease in elastic coefficients of HCC cells (K1: 68.7 N·m-2 to 81.7 N·m-2, 66.3% to 78.9%; K2: 34.5 N·m-2 to 37.1 N·m-2, 81.2% to 87.3%, P < 0.001) larger than those for normal hepatocytes (K1: 42.6 N·m-2 to 49.8 N·m-2, 48.7% to 56.9%; K2: 17.2 N·m-2 to 20.4 N·m-2, 51.7% to 61.3%, P < 0.001). There was a little decrease in the viscous coefficient of HCC cells (2.0 to 3.4 Pa•s, 44.4 to 75.6%, P < 0.001) than that for hepatocytes (3.0 to 3.9 Pa•s, 50.8 to 66.1% P < 0.001). Upon treatment with Col and VBL, the elastic coefficients of hepatocytes generally increased or tended to increase while those of HCC cells decreased. HTC cells with 72.1% of G1 phase and 98.9% of S phase were achieved and high K1, K2 value and low μ value were the general characteristics of HTC cells. G1 phase cells had higher K1 value and lower μ value than S phase cells had, and G1 phase HTC cells had stronger adhesive forces [(275.9 ± 232.8) × 10-10 N] than S phase cells [(161.2 ± 120.4) × 10-10 N, P < 0.001).

CONCLUSION: The difference in both the pattern and the magnitude of the effect of cytoskeletal perturbing agent on the viscoelastic properties between HCC cells and hepatocytes may reflect differences in the state of the cytoskeleton structure and function and in the sensitivity to perturbing agent treatment between these two types of cells. Change in the viscoelastic properties of cancer cells may affect significantly tumor cell invasion and metastasis as well as interactions between tumor cells and their micro-mechanical environments.

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