Department of Urology, PLA General Hospital, Beijing, People's Republic of China; State Key Laboratory of Kidney Diseases, PLA General Hospital, Beijing, People's Republic of China.
Int J Cancer. 2013 Dec 15;133(12):2801-11. doi: 10.1002/ijc.28306. Epub 2013 Jul 9.
Microtubules (Mts), which consist of α/β-tubulin heterodimers, are involved in cancer development and metastasis. Tubulin cofactor A (TBCA) plays crucial roles in modulating tubulin folding and α/β-tubulin heterodimer polymerization. Here, we identified the aberrant expression of TBCA in clear cell renal cell carcinoma (ccRCC) specimens as well as cell lines and revealed the function of TBCA as a novel positive regulator in ccRCC progression, invasion and metastasis. qRT-PCR, Western blot and immunohistochemistry assays confirmed that TBCA was significantly highly expressed in ccRCC specimens and cell lines compared to their corresponding normal kidney tissues and HKC. Accordingly, the influence of TBCA on cell proliferation, apoptosis and invasion/migration was detected through overexpression and knockdown of endogenous TBCA protein level in ccRCC cells via plasmids. Silencing of TBCA expression inhibited the proliferation of 786-O cells and Caki-1 cells and promoted the apoptosis of 786-O cells. Down-regulation of TBCA expression also reduced the invasion and migration ability of 786-O cells. Interestingly, overexpression of TBCA did not induce biocharacteristics that directly contrasted to those of TBCA knockdown. Importantly, exploration of the mechanism showed that TBCA could function via modulating cytoskeleton integration and influencing cell cycle progress. Furthermore, down-regulation of TBCA expression in 786-O and Caki-1 cells affected cytoskeleton integration and cell size, induced S/G2 cell cycle arrest and led to cyclineA/E and CDK2 aberrant expression. By investigating novel roles of TBCA in regulation of ccRCC cell progression, invasion and metastasis, our study identified that TBCA may be a potential molecular target for ccRCC therapy.
微管（Mts）由α/β-微管蛋白异二聚体组成，参与癌症的发生和转移。微管结合蛋白 A（TBCA）在调节微管折叠和α/β-微管蛋白异二聚体聚合中起着至关重要的作用。在这里，我们发现 TBCA 在透明细胞肾细胞癌（ccRCC）标本以及细胞系中存在异常表达，并揭示了 TBCA 作为 ccRCC 进展、侵袭和转移的新型正调控因子的功能。qRT-PCR、Western blot 和免疫组织化学检测证实，与相应的正常肾组织和 HKC 相比，TBCA 在 ccRCC 标本和细胞系中显著高表达。相应地，通过质粒过表达和内源性 TBCA 蛋白水平敲低，检测了 TBCA 对 ccRCC 细胞增殖、凋亡和侵袭/迁移的影响。TBCA 表达的沉默抑制了 786-O 细胞和 Caki-1 细胞的增殖，促进了 786-O 细胞的凋亡。下调 TBCA 表达也降低了 786-O 细胞的侵袭和迁移能力。有趣的是，过表达 TBCA 并没有诱导与 TBCA 敲低直接相反的生物特性。重要的是，机制探索表明 TBCA 可以通过调节细胞骨架整合和影响细胞周期进程来发挥作用。此外，下调 786-O 和 Caki-1 细胞中的 TBCA 表达影响细胞骨架整合和细胞大小，诱导 S/G2 细胞周期停滞，并导致 cyclineA/E 和 CDK2 异常表达。通过研究 TBCA 在调节 ccRCC 细胞进展、侵袭和转移中的新作用，我们的研究表明 TBCA 可能是 ccRCC 治疗的潜在分子靶点。
