27-羟基胆固醇在乳腺癌、前列腺癌和子宫内膜癌发生发展中的作用

血浆中最丰富的胆固醇初级代谢产物27-羟基胆固醇(27HC)是肝X受体(LXR)配体激动剂和内源性选择性雌激素受体调节剂(SERM),具有雌激素样作用,能促进肿瘤生长。研究发现27HC是多种恶性肿瘤发病的危险因素,参与肿瘤的发生,肿瘤微环境的调节以及肿瘤细胞增殖、血管生成、肿瘤细胞侵袭、迁移和转移等过程。同时,调控27HC含量的关键酶的表达也与27HC在肿瘤中的作用密切相关,可作为乳腺癌、前列腺癌等疾病预后复发的预测及监测生物标志物。本综述重点介绍了近年来27HC在乳腺癌、前列腺癌和子宫内膜癌中的研究成果,阐述了27HC在肿瘤生理病理过程中的雌激素受体(ER)和LXR依赖性作用及其对其它信号通路的调控作用,为防治相关癌症提供了新的理论依据和思路。

Internalization and half-life of membrane-bound macrophage colony-stimulating factor

The binding of recombinant human macrophage colony-stimulating factor (M-CSF) soluble receptor (rh-M-CSF-sR) to membrane-bound macrophage colony stimulating factor (m-M-CSF) and the internalization and recycling of rh-M-CSF-sR/m-M-CSF complexes mediated by m-M-CSF were studied with a model of J6-1 cell line. The results indicated that m-M-CSF bound rh-M-CSF-sR with high affinity (Kd= 1.78×10 12 mol/L) and mediated a temperature- and energy-dependent internalization of rh-M-CSF-sR, and that internalized rh-M-CSF-sR could return to the cell surface in an m-M-CSF-bound state, suggesting that m-M-CSF may have a capability to mediate the internalization and recycling of rh-M-CSF-sR/m-M-CSF complexes. In addition, the half-lives of cell-associated M-CSF and its receptor of stimulated normal human cord blood mononuclear cells (CBMCs) and 4 leukemic cell lines were measured by indirect immunoflu-orescence and flow cytometry. The results showed that the half-lives of the various kinds of M-CSF isoforms and