Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, No. 1277 Jiefangda Road, Wuhan, 430022, People's Republic of China.
Mol Cell Biochem. 2011 Jan;346(1-2):11-21. doi: 10.1007/s11010-010-0585-4. Epub 2010 Sep 9.
The ubiquitin specific peptidase 22 (USP22) is a positive regulator of the growth of tumors. However, little is known about the impact of USP22 knockdown on the growth of human bladder cells. In the present study, we designed a series of asymmetric interfering RNAs (aiRNAs) and compared the efficacy of aiRNA and conventional symmetric interfering RNA (siRNA) in the silencing of USP22 expression and the growth of human bladder EJ cells in vitro and in vivo. In comparison with transfection with the USP22-specific siRNA, transfection with 15/21 aiRNA was more potent in down-regulating the USP22 expression and inhibiting EJ cell proliferation in vitro. Furthermore, transfection with 15/21 aiRNA induced higher frequency of EJ cells arrested at the G0/G1 phases, but did not trigger EJ cell apoptosis. Moreover, transfection with either the siRNA or 15/21 aiRNA up-regulated the expression of p53 and p21, but down-regulated the expression of cyclin E and Mdm2 in EJ cells. The up-regulated p53 expression induced by the specific siRNA or aiRNA was abrogated by induction of Mdm2 over-expression. In addition, treatment with the specific siRNA or aiRNA inhibited the growth of implanted human bladder tumors in mice and the aiRNA had more potent anti-tumor activity in vivo. Therefore, our data suggest that knockdown of USP22 expression by the aiRNA may down-regulate the expression of Mdm2 and cyclin E, resulting in the up-regulated expression of p53 and p21 and leading to cell cycling arrest and inhibition of human bladder EJ cell proliferation. Our findings indicate that the USP22-specific aiRNA may be a novel approach for the intervention of human bladder tumors.
泛素特异性肽酶 22（USP22）是肿瘤生长的正向调节剂。然而，USP22 敲低对人膀胱细胞生长的影响知之甚少。在本研究中，我们设计了一系列不对称干扰 RNA（aiRNA），并比较了 aiRNA 和传统对称干扰 RNA（siRNA）在沉默 USP22 表达和体外及体内人膀胱 EJ 细胞生长中的效果。与转染 USP22 特异性 siRNA 相比，转染 15/21 aiRNA 更能下调 USP22 表达并抑制体外 EJ 细胞增殖。此外，转染 15/21 aiRNA 可诱导更高频率的 EJ 细胞停滞在 G0/G1 期，但不会引发 EJ 细胞凋亡。此外，siRNA 或 15/21 aiRNA 转染均可上调 EJ 细胞中 p53 和 p21 的表达，但下调 cyclin E 和 Mdm2 的表达。特异性 siRNA 或 aiRNA 诱导的 p53 表达上调可被诱导 Mdm2 过表达所阻断。此外，特异性 siRNA 或 aiRNA 治疗可抑制小鼠植入的人膀胱癌的生长，并且 aiRNA 在体内具有更强的抗肿瘤活性。因此，我们的数据表明，aiRNA 下调 USP22 表达可能下调 Mdm2 和 cyclin E 的表达，导致 p53 和 p21 的表达上调，导致细胞周期停滞并抑制人膀胱 EJ 细胞增殖。我们的研究结果表明，USP22 特异性 aiRNA 可能是干预人膀胱癌的新方法。
