Zhao W, Schorey J S, Bong-Mastek M, Ritchey J, Brown E J, Ratliff T L
Department of Urology, University of Iowa, Iowa City 52242-1089, USA.
Int J Cancer. 2000 Apr 1;86(1):83-8. doi: 10.1002/(sici)1097-0215(20000401)86:1<83::aid-ijc13>3.0.co;2-r.
Intravesical Mycobacterium bovis bacillus Calmette-Gu*erin (BCG) is the treatment of choice for superficial bladder cancer. Previous studies showed that attachment of BCG to fibronectin within the bladder was necessary for mediation of the antitumor response. Further studies identified a bacterial receptor, fibronectin attachment protein (FAP), as an important mediator of BCG attachment to fibronectin. In vitro studies showed that a stable BCG/fibronectin interaction was dependent on FAP binding to fibronectin; however, no role for FAP in the attachment of BCG in vivo has been characterized. We now report the cloning of the M. bovis BCG FAP (FAP-B) and demonstrate an important role for FAP in the in vivo attachment of BCG to the bladder wall and in the induction of BCG-mediated antitumor activity. The predicted amino acid sequence for FAP-B shows 61% and 71% homology, respectively, with Mycobacterium avium FAP (FAP-A) and Mycobacterium leprae FAP (FAP-L). Rabbit polyclonal antibodies against Mycobacterium vaccae FAP (FAP-V) reacted with all 3 recombinant FAP proteins on Western blots. Functional studies show FAP-B to bind fibronectin via the highly conserved attachment regions previously identified for FAP-A and FAP-L and also to competitively inhibit attachment of BCG to matrix fibronectin. In vivo studies show FAP to be a necessary protein for the stable attachment of BCG to the bladder wall. Moreover, stable binding of BCG via FAP was shown to be necessary for the expression of BCG-induced antitumor activity. Our results demonstrate a biological role for FAP in the mediation of BCG-induced antitumor activity.
膀胱内注射卡介苗（BCG）是浅表性膀胱癌的首选治疗方法。先前的研究表明，BCG在膀胱内与纤连蛋白结合是介导抗肿瘤反应所必需的。进一步的研究确定了一种细菌受体，即纤连蛋白附着蛋白（FAP），是BCG与纤连蛋白结合的重要介质。体外研究表明，稳定的BCG/纤连蛋白相互作用依赖于FAP与纤连蛋白的结合；然而，FAP在BCG体内附着中的作用尚未得到明确。我们现在报告牛分枝杆菌BCG FAP（FAP-B）的克隆，并证明FAP在BCG体内附着于膀胱壁以及诱导BCG介导的抗肿瘤活性中起重要作用。FAP-B的预测氨基酸序列分别与鸟分枝杆菌FAP（FAP-A）和麻风分枝杆菌FAP（FAP-L）具有61%和71%的同源性。抗母牛分枝杆菌FAP（FAP-V）的兔多克隆抗体在蛋白质印迹上与所有3种重组FAP蛋白发生反应。功能研究表明，FAP-B通过先前为FAP-A和FAP-L确定的高度保守的附着区域与纤连蛋白结合，并且还竞争性抑制BCG与基质纤连蛋白的附着。体内研究表明，FAP是BCG稳定附着于膀胱壁所必需的蛋白质。此外，通过FAP的BCG稳定结合被证明是BCG诱导的抗肿瘤活性表达所必需的。我们的结果证明了FAP在介导BCG诱导的抗肿瘤活性中的生物学作用。
