Instituto do Coração, Escola de Medicina, Universidade de São Paulo, São Paulo, SP Brazil.
Genet Mol Biol. 2010 Jan;33(1):17-22. doi: 10.1590/S1415-47572009005000104. Epub 2010 Mar 1.
E2F1 plays a key role in cell-cycle regulation in mammals, since its transcription factor activity controls genes required for DNA synthesis and apoptosis. E2F1 deregulation is a common feature among different tumor types and can be a major cause of cell proliferation. Thus, blocking E2F1 expression by RNA interference represents a promising therapeutic approach. In this study, the introduction of specific short hairpin RNAs (shRNAs) reduced E2f1 expression by up to 77%, and impaired rat glioma cell proliferation by approximately 70%, as compared to control cells. Furthermore, we investigated the expression of E2f1 target genes, Cyclin A and Cyclin E. Cyclin A was found to be down-regulated, whereas Cyclin E had similar expression to control cells, indicating that gene(s) other than E2f1 control its transcription. Other E2f family members, E2f2 and E2f3, which have been classified in the same subgroup of transcriptional activators, were also analyzed. Expression of both E2f2 and E2f3 was similar to control cells, showing no cross-inactivation or up-regulation to compensate for the absence of E2f1. Nevertheless, their expression was insufficient to maintain the initial proliferation potential. Taken together, our results suggest that shE2f1 is a promising therapy to control tumor cell proliferation.
E2F1 在哺乳动物的细胞周期调控中起着关键作用，因为其转录因子活性控制着 DNA 合成和细胞凋亡所需的基因。E2F1 的失调是不同肿瘤类型的共同特征，可能是细胞增殖的主要原因。因此，通过 RNA 干扰来阻断 E2F1 的表达是一种很有前途的治疗方法。在这项研究中，引入特定的短发夹 RNA（shRNA）可使 E2f1 的表达降低多达 77%，并使大鼠神经胶质瘤细胞的增殖减少约 70%，与对照细胞相比。此外，我们还研究了 E2f1 靶基因 Cyclin A 和 Cyclin E 的表达。结果发现 Cyclin A 的表达下调，而 Cyclin E 的表达与对照细胞相似，表明除了 E2f1 之外，还有其他基因控制其转录。其他 E2f 家族成员 E2f2 和 E2f3 也被归入同一转录激活亚组，也进行了分析。E2f2 和 E2f3 的表达与对照细胞相似，没有交叉失活或上调来补偿 E2f1 的缺失。然而，它们的表达不足以维持最初的增殖潜力。综上所述，我们的研究结果表明，shE2f1 是控制肿瘤细胞增殖的一种很有前途的治疗方法。
