Zou Zhi-Jian, Fan Lei, Wang Li, Xu Ji, Zhang Run, Tian Tian, Li Jian-Yong, Xu Wei
Department of Hematology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu Province Hospital, Nanjing, China.
Department of Hematology, Wuxi People Hospital Affiliated of Nanjing Medical University, Wuxi, China.
Oncotarget. 2015 Jan 20;6(2):1276-85. doi: 10.18632/oncotarget.2626.
We previous found the expression level of PTEN was low in the chronic lymphocytic leukemia (CLL) patients. To assess the pathogenic contribution of the low expression of PTEN, we determined PTEN-regulating miRNA interference, PTEN promoter methylation and PTEN gene mutation condition in CLL. One hundred and fifty-four previously untreated CLL patients and 200 cases of healthy controls were sequenced in exons 5-9 of PTEN. None of single nucleotide polymorphism site or mutation was detected in the coding sequences of those exons. Methylation of PTEN promoter was found in one (1.33%) of the 75 patients with CLL, but none of the 25 age-matched control subjects. We found that PTEN was a potential target of miR-26a and miR-214, which had been confirmed following dual-luciferase reporter assays, reverse transcription polymerase chain reaction and Western blotting. High expression of miR-26a was associated with advanced Binet stage (P=0.012), p53 aberrations (P=0.014) and inferior time to first treatment (P=0.038), and high expression of miR-214 was only associated with p53 aberrations (P=0.041). Inhibition of miR-26a or miR-214 could induce more apoptosis in primary cultured CLL cells. These findings support miR-26a and miR-214 down-regulate expression of PTEN in CLL, but not PTEN mutation or promoter methylation.
我们先前发现，慢性淋巴细胞白血病（CLL）患者中PTEN的表达水平较低。为了评估PTEN低表达的致病作用，我们测定了CLL中PTEN调控的miRNA干扰、PTEN启动子甲基化和PTEN基因突变情况。对154例未经治疗的CLL患者和200例健康对照进行PTEN第5-9外显子测序。在这些外显子的编码序列中未检测到单核苷酸多态性位点或突变。75例CLL患者中有1例（1.33%）检测到PTEN启动子甲基化，而25例年龄匹配的对照受试者中均未检测到。我们发现PTEN是miR-26a和miR-214的潜在靶点，双荧光素酶报告基因检测、逆转录聚合酶链反应和蛋白质印迹法已证实这一点。miR-26a高表达与Binet分期晚期（P=0.012）、p53异常（P=0.014）和首次治疗时间较短（P=0.038）相关，miR-214高表达仅与p53异常（P=0.041）相关。抑制miR-26a或miR-214可诱导原代培养的CLL细胞发生更多凋亡。这些发现支持miR-26a和miR-214在CLL中下调PTEN的表达，但与PTEN突变或启动子甲基化无关。
