上调骨髓基质细胞Cx43逆转N-cadherin介导的ALL细胞耐药作用及机制

The effects of treatment is poor on acute lymphoblastic leukemia(ALL),especially on T-ALL. Minimal residual disease (MRD) and drug resistance were main causes for the poor outcome of ALL.The“asylum”of hematopoietic microenvironment on leukemia cells is a very important factor in refractory leukemia. Applicants in the preliminary research discovered that the reduction or deficiency of Connexin43（Cx43）on the surface of leukemia bone marrow stromal cells contributes to residual leukemia cells and decreasing chemotherapy sensitivity, but the mechanism is not very clear by now. we found in pre-test that expression of N-cadherin was decreased which plays an important role in reversal of drug resistance followed Cx43 expression. Therefore, we put forward a hypothesis that " key transcription factor of EMT activated by low expression of CX43 in bone marrow stromal cells to promote the N-cadherin-mediated drug resistance", This study plans to build a residual disease model in vitro in which the bone marrow stromal cells from ALL patients are co-cultured with Jurkat cells . Using methods of RNAi, IHC ect. to detect the effect and mechanisms of that down regulations of the expression of Cx43 activate signal molecules of EMT, and then increase the expression of N-cadherin, which enhance the downstream gene ofβ-catenin Pathway expression, then lead to drug resistenc. We investigate the study to research the causes and mechanisms of ALL refractory from a new angle, which may provide some experimental basis for the removal of reversal of drug resistance, minimal residual disease and reducing the relapse.

急性淋巴细胞白血病（ALL），尤其是T-ALL疗效差，微小残留病和耐药是难以治愈的根源，造血微环境对ALL的“庇护”是重要因素。造血微环境主要功能成分骨髓基质细胞连接蛋白43（Cx43）的下调或缺失导致ALL细胞残留耐药但机制不明；预实验发现，上调基质细胞Cx43后N-钙黏蛋白（N-cadherin）下降，可逆转ALL细胞耐药。故本项目提出“骨髓基质细胞CX43下调激活EMT关键转录因子促进N-cadherin介导的白血病耐药”假说；拟在体外构建ALL骨髓基质细胞与Jurkat细胞（T-ALL）共培养残留耐药模型；通过基因沉默，免疫组化等方法阐明ALL基质细胞CX43下调，激活EMT关键转录因子，增强N-cadherin表达，促进ALL细胞β-catenin通路下游基因表达，诱导白血病细胞耐药的作用及机制。从新的角度探索ALL难治耐药原因和机制，为逆转白血病耐药，降低复发奠定实验基础。

急性淋巴细胞白血病（ALL），尤其是T-ALL疗效差，微小残留病和耐药是难以治愈的根源，造血微环境对ALL的“庇护”是重要因素。造血微环境主要功能成分骨髓基质细胞连接蛋白43（Cx43）的下调或缺失导致ALL细胞残留耐药但机制不明；通过实验研究发现，白血病患者骨髓基质细胞CX43下调，激活了基质细胞中EMT关键分子的表达从而增强N-cadherin表达；而N-cadherin介导骨髓基质细胞与白血病细胞间粘附增强，通过Wnt/β-catenin通路、PI3K/Akt和MAPK/Erk1/2等通路调控下游基因表达，发挥白血病细胞耐药的作用。通过逆转骨髓基质细胞CX43的表达能使N-cadherin表达下调，促进白血病细胞凋亡，从而逆转白血病耐药。从新的角度探索ALL难治耐药原因和机制，为逆转白血病耐药，降低复发奠定实验基础。