Dept. of Toxicology, School of Public Health, China Medical University, Shenyang, 110122, China.
Dept. of Thoracic Surgery Ward 2, The First Hospital of China Medical University, Shenyang, 110001, China.
Chem Biol Interact. 2021 Nov 1;349:109683. doi: 10.1016/j.cbi.2021.109683. Epub 2021 Oct 2.
Previous studies have shown that PPP1R13L as an inhibitor of apoptosis protease TP53 can lead to abnormal cell proliferation and carcinogenesis, however, the function of PPP1R13L was complicated and the interaction between TP53 and PPP1R13L needs to be further explored. In the present study, a malignant transformation model of human bronchial epithelial cells induced by benzo (a) pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) was established to observe the regulatory patterns between TP53 and PPP1R13L during carcinogenesis. In vitro experiments including CRISPR-Cas9 editing, RNA silence, Co-Immunoprecipitation and Chromatin Immunoprecipitation were applied to discuss their interactive effects. Additionally, TCGA data profile and our clinical samples of lung cancer were also used to analyze their relationship at the transcriptome level. Interestingly, we found that the mRNA and protein level of TP53 and PPP1R13L fluctuated as a wave in BPDE-induced malignant transformation under wild-type TP53 genetic background. Our results have also demonstrated that PPP1R13L acts as an inhibitor of TP53, while TP53 can regulate PPP1R13L via binding a possible enhancer of the first intron of PPP1R13L gene. Likewise, TCGA data and clinical samples have identified that in the case of TP53 mutation, TP53 expression was negatively correlated with PPP1R13L, while in the case of TP53 wild-type, TP53 expression was not correlated with PPP1R13L. It suggested that there existed a negative feedback of wild-type TP53 to PPP1R13L, which reminded a unique implication during chemical carcinogenesis.
先前的研究表明，作为凋亡蛋白酶 TP53 的抑制剂，PPP1R13L 可导致异常细胞增殖和癌变，然而 PPP1R13L 的功能复杂，TP53 与 PPP1R13L 之间的相互作用需要进一步探索。本研究建立了苯并(a)芘-7,8-二氢二醇-9,10-环氧化物（BPDE）诱导的人支气管上皮细胞恶性转化模型，以观察致癌过程中 TP53 和 PPP1R13L 之间的调控模式。体外实验包括 CRISPR-Cas9 编辑、RNA 沉默、共免疫沉淀和染色质免疫沉淀，用于探讨它们的相互作用。此外，还利用 TCGA 数据图谱和肺癌临床样本分析了它们在转录组水平的关系。有趣的是，我们发现野生型 TP53 遗传背景下，BPDE 诱导的恶性转化过程中，TP53 和 PPP1R13L 的 mRNA 和蛋白水平呈波动变化。我们的结果还表明，PPP1R13L 作为 TP53 的抑制剂，而 TP53 可以通过结合 PPP1R13L 基因第一内含子的可能增强子来调节 PPP1R13L。同样，TCGA 数据和临床样本也确定了在 TP53 突变的情况下，TP53 表达与 PPP1R13L 呈负相关，而在 TP53 野生型的情况下，TP53 表达与 PPP1R13L 不相关。这表明野生型 TP53 对 PPP1R13L 存在负反馈，这在化学致癌过程中具有独特的意义。
