基于eIF4E-Bmi1通路隐丹参酮干预急变期慢性粒细胞白血病的功能研究

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that originates in an abnormal pluripotent bone marrow stem cell and is consistently associated with the Bcr/Abl fusion gene. The disease is biphasic or triphasic; an initial indolent chronic phase (CP) is followed by one or both of the aggressive stages, the accelerated phase (AP) and blast crisis (BC), resulting in expansion of immature leukemic cells. The clinical application of a molecular targeting therapeutic agent termed imatinib mesylate has displayed a dramatic impact on treatment of patients with CP but not with BC. Thus, studies of CML and its progression to blast crisis may help elucidate the mechanisms of cancer progression and explore new therapy. .The eukaryotic translation initiation factor 4E (eIF4E) and The polycomb group (PcG) protein Bmi1 are elevated in the most chronic myeloid leukemia patients and probably associated with CML progression. Both of eIF4E and Bmi1 plays critical roles in the control of cell growth and proliferation. We recently found that the expression of Bmi1 was increased in eIF4E overexpression CML cells. Then, we investigated whether Bmi1 is directly regulated by eIF4E at translational level. Because of the abnormally expression of eIF4E and Bmi1, we explore the function of eIF4E-Bmi1 in blast crisis CML cells, including cell growth, apoptosis, differentiation, clonogenic potential, and in vivo leukemogenesis. .Cryptotanshinone (CPT) is a major active component of Salvia miltiorrhiza. In our previous studies, we found that CPT decreased cell viability of human CML cells by inhibiting eIF4E function while CPT slightly decreased cell viability of human bone marrow cells. Therefore, we analyze the function of CPT in CML cell growth, apoptosis, differentiation, clonogenic potential, and in vivo leukemogenesis..Our studies would establish eIF4E-Bmi1 as a critical axis in leukemogenesis, and perhaps in blastic transformation. eIF4E-Bmi1 may be a biomarker for blast crisis of CML, and its measurement at diagnosis can help predict overall survival and thus contribute to better therapeutic decisions. The studies on CPT raise the possibility that CPT inhibited the function of eIF4E-Bmi1 and could be developed as novel anticancer drugs.

慢性粒细胞白血病(CML)是一种造血干细胞恶性肿瘤，在进入急变期后，细胞分化受阻，具有较强致死性。深入研究急变期CML的调控机制，有助于开发更有效的治疗措施和靶向药物。本课题拟在急变期CML中研究翻译起始因子eIF4E、多梳家族蛋白Bmi1的关系，系统研究eIF4E调控Bmi1表达及调控机制；在临床样本中对eIF4E-Bmi1表达水平与CML病程进行分析；深入研究eIF4E-Bmi1对急变期CML细胞增殖、凋亡、分化、集落形成、体内成瘤能力等功能的影响；以eIF4E-Bmi1通路为切入点研究隐丹参酮干预急变期CML细胞的功能和分子机制。通过本研究将明确eIF4E与Bmi1的调控关系及eIF4E-Bmi1在急变期CML细胞中的功能，为急变期CML的治疗提供新的分子诊断标志和治疗靶点；隐丹参酮干预急变期CML细胞功能和机制的阐明为其在CML治疗中的应用提供了理论依据。

慢性粒细胞白血病(CML)是一种造血干细胞恶性肿瘤，常伴有与Bcr/abl基因融合，CML的病程分为慢性期、加速期和急变期，其病程转变的机制复杂。伊马替尼作为慢性期CML的首选药物，但对急变期CML病人效果不佳。阐明CML的病程转变的分子机制，寻找新的有效的药物和干预手段，将有利于急变期CML患者的临床治疗。.本课题以真核翻译起始因子eIF4E为研究对象，系统研究了eIF4E在CML细胞伊马替尼耐药过程中的功能，明确了eIF4E对伊马替尼化疗敏感性的调控作用，证明了抑制eIF4E的表达可提高伊马替尼对CML细胞的药效，eIF4E抑制剂利巴韦林可阻断胞内eIF4E的活性，并抑制下游靶点bcl-2、cyclin D1和c-myc的表达，利巴韦林与伊马替尼存在显著的协同作用；利巴韦林在体内无明显的抗肿瘤效果，但可显著提高伊马替尼在体内的抑瘤率，两者联合后体内的抑瘤率可达62.5%，本研究结果为急变期CML患者的治疗提供了新的治疗思路和方法。.在不同病程的CML患者临床标本中分析了eIF4E与Bmi1的表达水平变化，明确了两者表达的正相关性，证实了eIF4E-Bmi1通路的表达与CML急变期病程转变密切相关，确认eIF4E在CML细胞对Bmi1的表达调控功能，该研究为CML的急变期的病程转变的进一步研究提供了理论依据。.以eIF4E为切入点，证明了隐丹参酮(CPT)对eIF4E的活性抑制作用，并对其的体内外抗白血病功能进行了系统研究。明确了CPT可通过抑制eIF4E通路的活性，激活caspase依赖的凋亡途径，引起细胞G0/G1的细胞周期阻滞，发挥抗白血病功能；证实了CPT对伊马替尼体内外药效的影响，其作用机制不依赖于CML细胞中P-糖蛋白的表达抑制和胞内药物浓度的提高，而与Bcr-abl信号通路活性及其eIF4E、STAT3、mTOTR等下游靶点的活性降低有关，两者联合的体内抑瘤率可达60.2%。该研究明确了隐丹参酮与伊马替尼在治疗白血病中的“增效减毒”功能，阐明了两者协同的分子机制。.本项目的实施明确了eIF4E-Bmi1信号通路在CML患者病程转变和耐药过程中的调控功能，为抗白血病药物的开发提供了新的靶点；隐丹参酮体内外抗白血病功能的明确，为急变期耐药CML患者提供了新的化疗手段和策略，也为其进一步药物开发奠定了基础。