Department of Molecular Craniofacial Embryology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113‑8549, Japan.
Int J Oncol. 2021 Apr;58(4). doi: 10.3892/ijo.2021.5192. Epub 2021 Mar 2.
The AT‑rich interacting domain (ARID) family of DNA‑binding proteins is involved in various biological processes, including the regulation of gene expression during cell proliferation, differentiation and development. ARID3A and ARID3B are involved in chromatin remodeling and can bind to E2F1 and retinoblastoma tumor suppressor protein (RB), respectively. However, their role in regulating E2F target gene expression remains poorly understood. E2F transcription factors are critical regulators of cell cycle progression and are modulated by RB. Herein, putative ARID3‑binding sites (BSs) in E2F target genes were identified, including and , and it was found that ARID3A and ARID3B bound to these BSs in living cells. The mutation of ARID3 BSs reduced promoter activity, while ARID3A and ARID3B overexpression increased the promoter activity, depending on both ARID3 and E2F BSs. ARID3B knockdown blocked the transcription of and in normal human dermal fibroblasts (NHDFs), whereas the effects of ARID3A knockdown varied depending on the target genes. ARID3B overexpression, but not that of ARID3A, upregulated the transcription of E2F target genes, and activated transcription and induced cell death with E2F1 assistance. Finally, ARID3A and ARID3B knockdown attenuated the cell cycle progression of NHDFs and T98G cells, and suppressed tumor cell growth. On the whole, these results indicate that ARID3A and ARID3B play distinct and overlapping roles in E2F‑dependent transcription by directly binding to the E2F target genes. The present study provides novel insight into the mechanisms underlying the E2F dysregulation caused by ARID3A and ARID3B overexpression, which may have a significant influence on the progression of tumorigenesis.
富含 AT 的相互作用结构域 (ARID) 家族的 DNA 结合蛋白参与多种生物学过程，包括细胞增殖、分化和发育过程中的基因表达调控。ARID3A 和 ARID3B 参与染色质重塑，分别可以与 E2F1 和视网膜母细胞瘤肿瘤抑制蛋白 (RB) 结合。然而，它们在调节 E2F 靶基因表达中的作用仍知之甚少。E2F 转录因子是细胞周期进程的关键调节因子，受 RB 调节。在此，鉴定出 E2F 靶基因中的假定 ARID3 结合基序 (BS)，包括和 ，并发现 ARID3A 和 ARID3B 在活细胞中结合这些 BS。ARID3 BS 的突变降低了 启动子活性，而 ARID3A 和 ARID3B 的过表达增加了启动子活性，这取决于 ARID3 和 E2F BS。ARID3B 敲低阻断了正常人类真皮成纤维细胞 (NHDFs)中 和 的转录，而 ARID3A 敲低的影响则取决于靶基因。ARID3B 过表达而非 ARID3A 过表达上调了 E2F 靶基因的转录，并在 E2F1 协助下激活 转录并诱导细胞死亡。最后，ARID3A 和 ARID3B 敲低减弱了 NHDFs 和 T98G 细胞的细胞周期进程，并抑制了肿瘤细胞的生长。总的来说，这些结果表明 ARID3A 和 ARID3B 通过直接结合 E2F 靶基因，在 E2F 依赖性转录中发挥独特且重叠的作用。本研究为 ARID3A 和 ARID3B 过表达导致的 E2F 失调的机制提供了新的见解，这可能对肿瘤发生的进展有重大影响。
