靶向下敲MR-1诱导慢性粒细胞白血病分化及其作用机制研究

Chemotherapy is an important means for the treatment of leukemia. However, the rate of complete remission and long-term survival in leukemia treatment is still low, thus looking for novel target molecules and therapeutic approach is still an important research topic. Our institute discovered a new gene MR-1 that is associated with the tumorigenesis, development and metastasis, and also found that MR-1 is highly expressed in leukemia cells. Clinical data show that high expression of MR-1 in chronic myeloid leukemia cells in the acute phase and that knockdown of MR-1 can inhibit leukemia cell proliferation and differentiation, but its mechanism is not clear. In this study, we explore the relationship of the MR-1 and cell proliferation, differentiation, and its mechanism of action, including the abnormal expression of MR-1 in patients and leukemia cells, the effects of silencing MR-1 on proliferation and differentiation, the key nodes of MR-1, and signal transduction pathways, the efficiency of MR-1 knockdown on therapeutic drugs. Data will prove the functions of MR-1 in leukemia proliferation and differentiation, the role of MR-1-siRNA in leukemia treatment, as well as the possibility of MR-1 as an acute phase markers of chronic myeloid leukemia, and potential drug targets. The idea is from the concept of translational medicine, and the goal of basic theoretical study based on clinical results is to search for new therapeutic approaches and ultimately serve the clinical.

化疗是治疗白血病的重要手段，然而白血病的完全缓解率和长期生存率仍然低下，因此寻找新治疗靶分子和治疗途径仍然是重要的研究课题。我所发现的新基因MR-1与肝癌等肿瘤的发生、发展和转移相关，还发现MR-1在白血病细胞中高表达。临床数据表明MR-1在慢性粒细胞白血病急性期细胞中高表达，下调MR-1能抑制白血病细胞增殖和促进分化，但其作用机制不清楚。本课题探讨MR-1与细胞增殖、分化的关系和作用机制，包括MR-1在临床病人和白血病细胞中的异常表达，MR-1沉默后对细胞增殖和分化的影响，MR-1关键作用节点分子和信号转导途径，下敲MR-1对治疗性药物的增效性等。探明MR-1在白血病增殖、分化中的功能，MR-1-siRNA在白血病治疗中的作用，以及MR-1作为慢性粒细胞白血病急性期标志物和潜在药物靶点的可能性。本研究思路采用转化医学的理念，依据临床结果进行基础理论研究，寻找新治疗途径，最终用于临床。

MR-1是在许多人类癌症中通常过度表达的基因。然而，MR-1对细胞增殖，黏附，迁移和全基因组基因表达调控的影响目前仍不清楚。在本研究中，我们建立了高度过表达MR-1的人肿瘤细胞系。结果显示，高表达MR-1并没有促进细胞增殖与对照细胞相比，它显著增加细胞扩散，粘附和迁移。许多这些基因均与细胞粘附，细胞骨架调节，MAPK信号传导，细胞周期相关的通路。Western blot分析进一步证实了迁移由MR-1相关途径的调控。这些结果表明，MR-1是参与癌细胞粘附，迁移及相关基因表达的调控。进一步研究表明，MR-1在人血液系统恶性肿瘤细胞中的表达高于正常人淋巴细胞，尤其在K562细胞高表达，MR-1-siRNA可抑制人白血病细胞K562的增殖。MR-1下调可促进MAPK通路中ERK通路的活化，从而促进了Cyclin D1和CDK4抑制蛋白p21的表达，使得控制G0/G1期Rb磷酸化降低，抑制了E2F因子的作用，使周期停滞在G0/G1期，使得细胞增殖减缓，同时也使得胞浆逐渐成熟并合成血小板粘附蛋白和表面分子标志CD41，增加了细胞相互间的粘附性，形成了实验中所见的较大细胞簇。Cyclin D1的高表达可促进细胞多倍体的形成，并在这个过程中Caspase-3被激活从而促进了凋亡，完成分化过程。研究阐明了MR-1基因在慢性白血病分化中的重要作用。