黏着斑激酶在骨肉瘤中的表达及临床意义

Clinical significance of expression and phosphorylation of FAK in human osteosarcoma

目的:探讨骨肉瘤组织中黏着斑激酶(focal adhesion kinase,FAK)的表达情况及其与临床病理特征和预后的关系。方法:收集1999年12月至2011年l2月东南大学附属中大医院和南京军区南京总医院收治的经手术病理确诊的骨肉瘤标本113例,免疫组织化学检测病灶中FAK表达量及磷酸化水平,并通过RNA干扰观察改变FAK的表达与激活水平对骨肉瘤细胞增殖、凋亡、迁移及侵袭活动的影响。结果:70例标本(61.95%)FAK过表达,其中42例(37.17%)p FAK阳性。FAK表达谱与性别、年龄、AJCCⅡA/ⅡB期、病灶部位、术式、术前化疗效果等临床病理参数均无显著相关性。生存分析显示FAK的过表达及其磷酸化显著缩短了总生存时间(overall survival,OS)和无转移生存时间(metastasis-free survival,m FS),其与术前化疗效果是预测骨肉瘤生存时间和转移早晚的两个独立预后因素。细胞学实验则显示FAK的表达和激活可以促进骨肉瘤细胞的增殖、迁移及侵袭活动,并能抑制凋亡。结论:FAK的过表达及其磷酸化与骨肉瘤恶性程度密切相关,可为生存期及预后判断提供一定参考。

Objective： To examine expression patterns of focal adhesion kinase （FAK） and its activated form, phosphorylated FAK （pFAK）, in human osteosarcoma and to investigate the correlation of FAK expression with clinicopathological parameters and prognosis. Functional consequence of manipulating FAK protein levels was also investigated in human osteosarcoma cell lines. Methods： Immunohistochemical staining was used to detect FAK and pFAK levels in pathologically archived materials from 113 patients with primary osteosarcoma. KaplanMeier survival and Cox regression analyses were used to evaluate prognoses. The role of FAK in cytological behavior of MG63 and 143B human osteosarcoma cell lines was studied via the FAK protein knockdown with siRNA. Cell proliferation, migration, invasiveness, and apoptosis were assessed using cell counting kit-g, Transwell, and Annexin V/P1 staining methods. Results： Both FAK and pFAK were overexpressed in osteosarcoma patients. Tumor cells exhibited cytoplasmicity and occasional membranous immunoreactivity for FAK. A total of 42 cases （37.17%） mainly showed expressed pFAK in cytoplasm of osteosarcoma cells. No overexpression staining of anti-FAK and anti-pFAK antibodies was observed in normal cancellous bone tissues or negative controls. Significant differences were observed in overall survival between FAK-/pFAK- and FAK＋/pFAK- groups （P=0.016）, FAK＋/pFAK- and FAK＋/pFAK＋ groups （P=0.012）, and FAK-/pFAK- and FAK＋/ pFAK＋ groups （P〈0.001）. All groups showed similar metastasis-free survival. Cox proportional hazard analysis showed that FAK expression profile is an independent indicator of both overall and metastasis-free survival, siRNA-based knockdown of FAK significantly reduced migration and invasion of MG63 and 143B cells and affected proliferation and apoptosis in osteosarcoma cells. Conclusion： Osteosarcoma malignancies in vitro and in vivo were correlated with overexpression and phosphorylation of FAK. These findings suggest that FAK plays an important biological role in osteosarcoma carcinogenesis. This study provides a better understanding of diagnostic and prognostic relevance of FAK overexpression and phosphorylation in osteosarcoma patients. Therefore, FAK and pFAK can be used as independent predictors of overall and metastasis-free survival in osteosarcoma patients.