Table_4_Inactivation of Prostaglandin E2 as a Mechanism for UGT2B17-Mediated Adverse Effects in Chronic Lymphocytic Leukemia.xlsx

High expression of the metabolic enzyme UDP-glucuronosyltransferase UGT2B17 in chronic lymphocytic leukemia (CLL) cells was associated with poor prognosis in two independent studies. However, the underlying mechanism remains unknown. We hypothesized that UGT2B17 impacts intracellular levels of hormone-like signaling molecules involved in the regulation of gene expression in leukemic cells. We initially confirmed in a third cohort of 291 CLL patients that those with high UGT2B17 displayed poor prognosis (hazard ratio of 2.31, P = 0.015). Consistent with the unfavorable prognostic significance of elevated UGT2B17 expression in CLL patients, high UGT2B17 expression was associated with enhanced proliferation of MEC1 and JVM2 malignant B-cell models. Transcriptomic analyses revealed that high UGT2B17 was linked to a significant alteration of genes related to prostaglandin E2 (PGE2) and to its precursor arachidonic acid, both in cell models and a cohort of 448 CLL patients. In functional assays, PGE2 emerged as a negative regulator of apoptosis in CLL patients and proliferation in cells models, whereas its effect was partially abrogated by high UGT2B17 expression in MEC1 and JVM2 cells. Enzymatic assays and mass-spectrometry analyses established that the UGT2B17 enzyme inactivates PGE2 by its conjugation to glucuronic acid (GlcA) leading to the formation of two glucuronide (G) derivatives. High UGT2B17 expression was further associated with a proficient inactivation of PGE2 to PGE2-G in CLL patient cells and cell models. We conclude that UGT2B17-dependent PGE2 glucuronidation impairs anti-oncogenic PGE2 effects in leukemic cells, thereby partially contributing to disease progression in high UGT2B17 CLL patients.

在两项独立研究中，慢性淋巴细胞白血病（CLL）细胞中代谢酶UDP-葡萄糖醛酸基转移酶UGT2B17的高表达与不良预后相关。然而，其潜在机制尚未明了。本研究假设UGT2B17影响参与白血病细胞基因表达调控的激素样信号分子在细胞内的水平。在291名CLL患者的第三队列中，我们首先证实了高UGT2B17表达者预后较差（风险比2.31，P=0.015）。与高UGT2B17表达在CLL患者中不良的预后意义一致，高UGT2B17表达与MEC1和JVM2恶性B细胞模型的增殖增强相关。转录组分析揭示了高UGT2B17与前列腺素E2（PGE2）及其前体花生四烯酸相关基因的显著改变相关，这一现象在细胞模型和448名CLL患者的队列中均有发现。在功能实验中，PGE2在CLL患者中表现为细胞凋亡的负调节因子，而在细胞模型中则抑制增殖，但其部分效应被MEC1和JVM2细胞中高UGT2B17表达所抵消。酶学实验和质谱分析证实，UGT2B17酶通过将PGE2与葡萄糖醛酸（GlcA）结合，从而使其失活并形成两种葡萄糖苷酸（G）衍生物。高UGT2B17表达进一步与CLL患者细胞和细胞模型中PGE2向PGE2-G的有效失活相关。我们得出结论，UGT2B17依赖的PGE2葡萄糖苷化损害了抗肿瘤性PGE2在白血病细胞中的作用，从而部分导致了高UGT2B17表达CLL患者的疾病进展。