Medical Integration and Practice Center, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China; Department of Breast and Thyroid Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China.
Department of Thoracic Surgery, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China.
Biochim Biophys Acta Gen Subj. 2023 Dec;1867(12):130498. doi: 10.1016/j.bbagen.2023.130498. Epub 2023 Oct 27.
RNA modification, a major component of post-transcriptional modification, plays an essential role in tumor initiation and progression. N4-acetylcytidine (ac4C) present in different species as a highly conserved RNA modification. ac4C on mRNA increases the stability of mRNA and the efficiency of protein translation. However, the mRNA profiling of ac4C in lung adenocarcinoma (LUAD) is unknown.
NAT10 expression was tested using immunohistochemistry in tissue microarray (TMA). The ac4C peaks on mRNA were identified through acetylated RNA immunoprecipitation sequencing in both human LUAD tissues and adjacent non-tumor tissues, and differences of acetylation and mRNA between the two groups were analyzed. Furthermore, the function of AC4C-specific acetylated transcripts was analyzed bioinformatically. And a ac-RIP-PCR was used to verify the ac4C acetylation sites of TFAP2A.
The expression of acetylated key enzyme NAT10 was obviously increased in LUAD group. Then we found noticeable differences in ac4C mRNA modification between LUAD and adjacent non-tumor tissues. In addition, bioinformatics analysis showed that the distinctive distribution pattern of mRNA ac4C in LUAD affects a variety of cellular functions, such as protein sumoylation and transmembrane transporter activity. Importantly, we verified the ac4C level of TFAP2A was up-regulated in LUAD.
Our study revealed that the degree of ac4C in mRNA in LUAD was significantly higher than in adjacent tissues and was concentrated mainly in the coding sequences with a implications in a wide range of cellular functions. The ac4C may become a new molecular marker and treatment target for lung cancer.
RNA 修饰是转录后修饰的主要组成部分，在肿瘤的发生和发展中起着至关重要的作用。N4-乙酰胞嘧啶（ac4C）作为一种高度保守的 RNA 修饰，存在于不同物种中。mRNA 上的 ac4C 增加了 mRNA 的稳定性和蛋白质翻译的效率。然而，肺腺癌（LUAD）中 ac4C 的 mRNA 谱尚不清楚。
采用免疫组织化学法在组织微阵列（TMA）中检测 NAT10 的表达。通过乙酰化 RNA 免疫沉淀测序（ac-RIP-seq）分别在人 LUAD 组织和相邻非肿瘤组织中鉴定 mRNA 上的 ac4C 峰，并分析两组间的乙酰化和 mRNA 差异。此外，还通过生物信息学分析了 AC4C 特异性乙酰化转录本的功能。并用 ac-RIP-PCR 验证了 TFAP2A 的 ac4C 乙酰化位点。
LUAD 组中乙酰化关键酶 NAT10 的表达明显增加。然后，我们发现 LUAD 与相邻非肿瘤组织之间的 ac4C mRNA 修饰存在明显差异。此外，生物信息学分析表明，LUAD 中 ac4C mRNA 修饰的独特分布模式影响多种细胞功能，如蛋白质 SUMO 化和跨膜转运体活性。重要的是，我们验证了 TFAP2A 的 ac4C 水平在 LUAD 中上调。
我们的研究表明，LUAD 中 mRNA 的 ac4C 程度明显高于相邻组织，主要集中在编码序列中，这对广泛的细胞功能具有重要意义。ac4C 可能成为肺癌的一个新的分子标志物和治疗靶点。
