CD44对骨肉瘤细胞增殖、黏附和侵袭性的影响

目的研究细胞表面黏附分子CD44对骨肉瘤细胞增殖、黏附和侵袭特性的影响,探讨骨肉瘤细胞生长侵袭的机制。方法流式细胞术和Westernblot检测3株骨肉瘤细胞系MG63、HOS和U2-OS中CD44的阳性表达率和相对蛋白含量;逆转录聚合酶链反应(RTPCR)法研究3株细胞系之间CD44mRNA的表达差异;同时应用MTT法、美蓝硼酸盐法和微孔迁移技术研究阻断CD44的作用前后3株细胞的增殖、黏附和侵袭能力的变化。结果HOS和U2-OS中CD44的阳性百分率均高于99%,但HOS中CD44的平均荧光强度显著高于U2-OS(P<0.01);而MG63中CD44阳性百分率仅为(2.10±0.46)%;Westernblot亦证明HOS中CD44的蛋白含量显著高于U2-OS(P<0.05),而MG-63中CD44表达为阴性;CD44mRNA在HOS和U2OS中的表达也显著高于MG-63(P值均<0.05)。HOS的侵袭性显著高于MG63和U2-OS(P值均<0.01);HOS与MG63的增殖速率和黏附性差异无统计学意义,但均显著高于U2OS(P值均<0.01)。应用中和抗体阻断CD44的作用之后,HOS和MG-63的黏附性均显著降低(P值均为0.03),U2-OS的黏附性无明显变化(P=0.93);HOS和U2-OS的侵袭力显著降低(P值均<0.01),而MG-63的侵袭力无明显改变(P=0.18);3株细胞的增殖速率均无显著变化(P值均>0.05)。结论CD44能促进骨肉瘤细胞系HOS的黏附和侵袭,并参与U2-OS的侵袭和MG-63的黏附过程,但是不影响骨肉瘤细胞的增殖速率。

The role of CD44 in the proliferation, adhesiveness and invasiveness of osteosarcoma cell lines

OBJECTIVE: To study the influence of CD44 a cell-matrix adhesion molecule on the proliferation, adhesiveness and invasiveness of osteosarcoma cell lines, in order to investigate the growth and invasion mechanism of osteosarcoma. METHODS: Three osteosarcoma cell lines MG-63, HOS and U2-OS were routinely cultured. Flow cytometry and Western blot analysis were used for detecting the positive rates and relative amount of CD44 protein in the three cell lines. RT-PCR method was also used to compare the differences in the expression of CD44 mRNA among the 3 cell lines. Then, MTT method, adhesion detection, and Microcon-migration assay were used to detect the changes of the cells' proliferation rate, adhesive and invasive abilities after blocking the role of CD44 by using a special neutralizing antibody. RESULTS: The results of flow cytometry showed that the percentage of CD44 positive cells were both over 99% in HOS and U2-OS, while that in MG-63 was only (2.10 +/- 0.46)%. The average fluorescence density of CD44 in HOS was significantly higher than in U2-OS. Western blot also showed that the relative content of CD44 protein in HOS was notably higher than that in U2-OS, while CD44 was negatively expressed in MG-63. The expression of CD44 mRNA was significantly lower in MG-63 than in both HOS and U2-OS, which were consistent with the expression of CD44 protein. The proliferation rates and adhesive abilities of MG-63 and HOS have no significant difference, but both were significantly higher than that of U2-OS. The invasive abilities of HOS was dramatically higher than MG-63 and U2-OS. After the role of CD44 was blocked by anti-CD44 neutralizing antibody, the proliferation rates of the 3 cell lines did not change significantly. While the HOS and MG-63 adhesion indices decreased dramatically (P < 0.05), the invasive abilities of HOS and U2-OS also decreased notably (P < 0.01). CONCLUSIONS: CD44 could promote the adhesiveness and invasiveness of osteosarcoma cell line HOS. CD44 may take part in promoting the process of U2-OS invasion and the adhesion of MG-63. On the other hand, CD44 could not affect the osteosarcoma cell proliferation rates.