目的 探讨FLT3及C-kit基因突变在急性髓细胞白血病(AML)中的临床意义。方法 回顾性分析南方医院2010年1月—2013年12月期间初诊AML患者的临床资料,PCR分析FLT3及C-kit基因突变情况。结果 248例初诊AML患者中, FLT3-ITD突变率为16.9%,TKD突变率为3.2%,C-kit8号外显子突变率为1%,17号外显子突变率为5.2%;FLT3-ITD突变更倾向发生于正常染色体核型的AML患者;FLT3突变阳性组及C-kit突变阳性组患者的外周血白细胞数高于基因突变阴性组,染色体核型正常患者的无病生存时间较阴性组缩短(P<0.05)。但是对血红蛋白、血小板及完全缓解率(CR率)并无影响(P>0.05)。结论 FLT3及C-kit突变的AML患者有较差的临床预后。

Objective This study was to investigate the prognostic value of FLT3 and C-kit gene mutations in patients with acute myeloid leukemia (AML). Methods We retrospect and analyzed the data of the 248patients with newly diagnosed AML from January 2013 to December 2010. FLT3 and C-kit gene mutations was detected by Polymerase chain reaction (PCR). Results Among these 248 subjects, the FLT3-ITD mutation rate was 16.9%, FLT3-TKD was 3.2%, C-kit 8 exon mutation rate was 1% and 17exon mutationwas 5.2%. FLT3-ITD mutation likely occurred in AML patients with normal karyotype. The patients with FLT3-ITD mutation or C-kit mutation had significantly higher PWBC and shorter DFS than patients without gene mutations (P< 0.05), but there was no significantly differences in sex, age, Hb, PLT and CR rate of the first course induction chemotherapy among groups (P>0.05). Conclusion Among patients with AML,FLT3-ITD and C-kit mutations were associated with worse prognosis.

       目的  探讨重楼皂苷Ⅰ（PPI）对慢性髓系白血病细胞（K562）细胞的抑制作用及可能的作用机制。方法  采用CCK-8法筛选药物最适浓度，将培养时间为24 h的药物最适浓度作为后续实验的干预浓度。分组如下：（1）空白组；（2）PPI组；（3）抑制剂组；（4）PPI+抑制剂组。采用CCK-8法检测细胞增殖率；AO/EB染色观察细胞形态；流式细胞术检测凋亡率；ROS检测试剂盒检测活性氧（ROS）含量、还原型谷胱甘肽含量检测试剂盒检测谷胱甘肽（GSH）含量、细胞亚铁比色法测试盒检测细胞亚铁（Fe²⁺）含量；qRT-PCR法和蛋白免疫印迹法检测各组肿瘤蛋白53（p53）、钠氯离子依赖性氨基酸转运蛋白11（SLC7A11）、谷胱甘肽过氧化物酶4（GPX4）mRNA及蛋白表达量。结果  PPI抑制K562细胞的生长，且呈一定的剂量及时间依赖性（与同时间段的对照组0μmol/L比较，均P＜0.01）。与空白组相比，PPI抑制K562细胞的增殖，提高了凋亡率，而铁死亡抑制剂（Ferrostian-1）的使用逆转了PPI对K562凋亡的促进作用（P＜0.01）。与空白组相比，PPI组ROS、Fe²⁺含量升高，GSH含量下降，而铁死亡抑制剂的使用可下调ROS、Fe²⁺，上调GSH的含量（P＜0.01）。PPI组较空白组p53 mRNA和蛋白表达水平升高，而SLC7A11、GPX4 mRNA和蛋白表达水平下降（P＜0.05）；PPI+抑制剂组细胞较重楼皂苷组p53 mRNA和蛋白表达水平下降，而SLC7A11、GPX4 mRNA和蛋白表达水平升高（P＜0.05）。结论  PPI能够有效抑制K562细胞增殖，促进K562细胞铁死亡，其分子机制可能与p53信号通路的调控有关。

       Objective  To investigate the inhibitory effect of polyphyllin I（PPI）on chronic myeloid leukemia cells（K562）and its possible mechanism．Methods  K562 cell line was cultured in suitable environment，and the optimal concentration of the drug was screened by CCK-8 method．The optimal concentration of the drug cultured for 24 hours was used as the intervention concentration of the follow-up experiment．Cells were divided into the following groups：（1）blank group，（2）saponins group，（3）inhibitor group and（4）saponins + inhibitor group．The cell proliferation rate was detected by CCK-8 method．The cell morphology was observed by AO/EB staining．The apoptosis rate was detected by flow cytometry．The contents of  reactive oxygen species（ROS），glutathione（GSH）and ferrous（Fe²⁺）in different groups were detected，and the expression of mRNA and protein in different groups were detected by qRT- PCR and Western blot respectively．Results  PPI significantly inhibited the growth of K562 cells in a dose-and time-dependent manner．Compared with the blank group，PPI significantly inhibited the proliferation of K562 cells and increased the apoptosis rate of K562 cells，while the use of ferroptosis inhibitor（Ferrostian-1）reversed the promoting effect of PPI on apoptosis of K562 cells．Compared with the blank group，the contents of reactive oxygen species（ROS）and ferrous iron（Fe²⁺）increased and the content of glutathione（GSH）decreased in the saponins group．The use of Ferrostian-1 could down-regulate the contents of ROS and Fe²⁺ and increase the content of GSH in the cells treated with the drug．Compared with the blank group，the expression of p53 mRNA and protein in the saponins group increased，while the expression of SLC7A11，GPX4 mRNA and protein decreased．The expression of p53 mRNA and protein in the saponins + inhibitor group was lower than that in the saponins group，while the expression levels of SLC7A11，GPX4 mRNA and protein increased．Conclusions  PPI can effectively inhibit the proliferation of K562 cells and promote ferroptosis in K562 cells．The molecular mechanism can be related to the regulation of p53 signal pathway．

    CCAAT增强子结合蛋白A（CEBPA）是调节血液发育过程中髓系分化和造血干祖细胞活性的关键转录因子之一。CEBPA基因突变常见于急性髓系白血病（AML）中，最近研究表明CEBPA bZIP框内单位点和经典双等位基因突变AML患者均具有类似的临床特征，已被单独划分为AML亚群。CEBPA bZIP框内突变而非传统的双等位CEBPA基因突变成为AML良好预后的分子指标，表明其在AML疾病进展和治疗预后中的重要性和特殊性。本文将从CEBPA蛋白在血液系统中的功能、CEBPA bZIP框内突变AML的临床特征与分子作用机制、以及伴CEBPA突变AML的治疗现状等方面进行综述，为进一步研究CEBPA bZIP框内突变在AML中的致病性和精准治疗新药物开发提供参考。

   CAAT enhancer-binding protein A（CEBPA）is one of the  key transcription factors  regulating myeloid differentiation and hematopoietic stem/progenitor cell maintenance during hematopoiesis．CEBPA gene mutations are commonly found in acute myeloid leukemia（AML）．Recent studies have demonstrated that AML patients haboring single CEBPA bZIP in-frame mutations or classical bi-allelic CEBPA mutations show similar clinical features and it has been individually classified as AML subgroup．Additionally，it is CEBPA bZIP in-frame mutations rather than the traditional biallelic CEBPA mutations that have emerged as a molecular indicator of favorable prognosis for clinical AML management，suggesting its importance and specificity in AML disease progression and therapeutic prognosis．Here，we reviewed serval aspects including the hematopoietic function of CEBPA protein，the clinical features and molecular mechanisms of AML with CEBPA bZIP in-frame mutations，and the current status of the treatment of AML with CEBPA mutations，which will provide a reference for further study of the pathogenicity of CEBPA bZIP in-frame mutations in AML and the development of new drugs for precision therapy．