Zhang Cheng, Yu Miaomiao, Hepperla Austin J, Zhang Zhao, Raj Rishi, Zhong Hua, Zhou Jin, Hu Lianxin, Fang Jun, Liu Hongyi, Liang Qian, Jia Liwei, Liao Chengheng, Xi Sichuan, Simon Jeremy M, Xu Kexin, Liu Zhijie, Nam Yunsun, Kapur Payal, Zhang Qing
Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Lineberger Comprehensive Cancer Center, University of North Carolina (UNC) School of Medicine, Chapel Hill, North Carolina, USA.
J Clin Invest. 2024 Apr 15;134(8):e175703. doi: 10.1172/JCI175703.
N6-Methyladenosine (m6A) is the most abundant posttranscriptional modification, and its contribution to cancer evolution has recently been appreciated. Renal cancer is the most common adult genitourinary cancer, approximately 85% of which is accounted for by the clear cell renal cell carcinoma (ccRCC) subtype characterized by VHL loss. However, it is unclear whether VHL loss in ccRCC affects m6A patterns. In this study, we demonstrate that VHL binds and promotes METTL3/METTL14 complex formation while VHL depletion suppresses m6A modification, which is distinctive from its canonical E3 ligase role. m6A RNA immunoprecipitation sequencing (RIP-Seq) coupled with RNA-Seq allows us to identify a selection of genes whose expression may be regulated by VHL-m6A signaling. Specifically, PIK3R3 is identified to be a critical gene whose mRNA stability is regulated by VHL in a m6A-dependent but HIF-independent manner. Functionally, PIK3R3 depletion promotes renal cancer cell growth and orthotopic tumor growth while its overexpression leads to decreased tumorigenesis. Mechanistically, the VHL-m6A-regulated PIK3R3 suppresses tumor growth by restraining PI3K/AKT activity. Taken together, we propose a mechanism by which VHL regulates m6A through modulation of METTL3/METTL14 complex formation, thereby promoting PIK3R3 mRNA stability and protein levels that are critical for regulating ccRCC tumorigenesis.
N6-甲基腺苷（m6A）是最丰富的转录后修饰，其对癌症进展的作用最近已得到认可。肾癌是最常见的成人泌尿生殖系统癌症，其中约85%由以VHL缺失为特征的透明细胞肾细胞癌（ccRCC）亚型引起。然而，尚不清楚ccRCC中VHL缺失是否会影响m6A模式。在本研究中，我们证明VHL结合并促进METTL3/METTL14复合物的形成，而VHL缺失则抑制m6A修饰，这与其经典的E3连接酶作用不同。m6A RNA免疫沉淀测序（RIP-Seq）与RNA测序相结合，使我们能够鉴定出一系列其表达可能受VHL-m6A信号传导调节的基因。具体而言，PIK3R3被确定为一个关键基因，其mRNA稳定性以m6A依赖但HIF独立的方式受VHL调节。在功能上，PIK3R3缺失促进肾癌细胞生长和原位肿瘤生长，而其过表达则导致肿瘤发生减少。机制上，VHL-m6A调节的PIK3R3通过抑制PI3K/AKT活性来抑制肿瘤生长。综上所述，我们提出了一种机制，即VHL通过调节METTL3/METTL14复合物的形成来调节m6A，从而促进对调节ccRCC肿瘤发生至关重要的PIK3R3 mRNA稳定性和蛋白质水平。
