Arsenic trioxide (ATO) is a therapeutic agent used to treat acute promyelocytic leukemia (APL), a disease caused by a chromosomal translocation of the retinoic acid receptor α (RARα) gene that can occur reciprocally with the promyelocytic leukemia (PML) gene. The mechanisms through which ATO exerts its effects on cells are not fully characterized though they involve the SUMOylation, the ubiquitylation, and the degradation of the PML/RARα oncoprotein through the PML moiety. To better understand the mechanisms that underlie the cytotoxicity induced with increasing ATO levels, we profiled the changes in protein SUMOylation, phosphorylation, and ubiquitylation on HEK293 cells following exposure to low (1 μM) or elevated (10 μM) ATO for 4 h. Our analyses revealed that a low dose of ATO resulted in the differential modification of selected substrates including the SUMOylation (K380, K394, K490, and K497) and ubiquitylation (K337, K401) of PML. These experiments also highlighted a number of unexpected SUMOylated substrates involved in DNA damage response (e.g., PCNA, YY1, and poly[ADP-ribose] polymerase 1 (PARP1)) and messenger RNA (mRNA) splicing (e.g., ACIN1, USP39, and SART1) that were regulated at higher ATO concentrations. Interestingly, additional enzymatic assays revealed that SUMOylation of PARP1 impeded its proteolytic cleavage by caspase-3, suggesting that SUMOylation could have a protective role in delaying cell apoptosis.

中文翻译：

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三氧化二砷处理后泛素样修饰剂的相互作用。

三氧化二砷（ATO）是一种用于治疗急性早幼粒细胞白血病（APL）的治疗剂，这种疾病是由视黄酸受体α（RARα）基因的染色体易位引起的，可与早幼粒细胞白血病（PML）基因相互发生。尽管ATO涉及SUMO酰化，泛素化和PML /RARα癌蛋白通过PML部分的降解，但尚未完全表征ATO对细胞产生作用的机制。为了更好地理解ATO水平升高所诱导的细胞毒性的基本机制，我们对HEK293细胞暴露于低（1μM）或升高（10μM）ATO 4 h后蛋白质SUMO酰化，磷酸化和泛素化的变化进行了分析。我们的分析表明，低剂量的ATO会导致所选底物的差异修饰，包括SUMOylation（K380，K394，K490和K497）和PML的泛素化（K337，K401）。这些实验还强调了涉​​及DNA损伤反应的许多意想不到的SUMO化底物（例如PCNA，YY1和聚[ADP-核糖]聚合酶1（PARP1））和信使RNA（mRNA）剪接（例如ACIN1，USP39和SART1）的ATO浓度较高。有趣的是，其他酶促测定表明，PARP1的SUMOylation阻碍了caspase-3的蛋白水解切割，表明SUMOylation可能在延迟细胞凋亡中起保护作用。这些实验还强调了涉​​及DNA损伤反应的许多意想不到的SUMO化底物（例如PCNA，YY1和聚[ADP-核糖]聚合酶1（PARP1））和信使RNA（mRNA）剪接（例如ACIN1，USP39和SART1）的ATO浓度较高。有趣的是，其他酶促测定表明，PARP1的SUMOylation阻碍了caspase-3的蛋白水解切割，表明SUMOylation可能在延迟细胞凋亡中起保护作用。这些实验还强调了许多意外的SUMO化底物，涉及DNA损伤反应（例如PCNA，YY1和聚[ADP-核糖]聚合酶1（PARP1））和信使RNA（mRNA）剪接（例如ACIN1，USP39和SART1）的ATO浓度较高。有趣的是，其他酶促测定表明，PARP1的SUMOylation阻碍了caspase-3的蛋白水解切割，表明SUMOylation可能在延迟细胞凋亡中起保护作用。