吲哚胺2,3-双加氧酶抑制剂逆转乳腺癌紫杉醇耐药性的机制研究

1-MT exhibit antitumor activity through inhibiting the increasing of Indoleamine 2,3-dioxygenase(IDO) in tumor microenvironment which leads to the T cell anergy. In recent years, it was found that high IDO expression leads to the activation of certain signaling pathways and membrane molecules transporters to change the tumor biological characteristics, including JNK and Wnt pathways which was closely.related to the chemotherapy resistance. In our preliminary study, it was found that IDO was expressed in relatively higher level in drug resistant tumor cells. In present research, the influence of 1-MT on paclitaxel(PTX) resistance was studied through applying PTX combined with 1-MT to PTX resistant breast cancer cells, including MCF-7/PTX cells which had higher IDO expressing and MDA-MB-231/PTX cells which had lower IDO expressing, in conducted/transwell co-culture system with T cells respectively. It was discussed that whether reversing effect of 1-MT on the PTX resistance relies on enhancing T cell function and stimulating release of cytokines which was examined by cytokine antibody chips to screen key cytokines. Meanwhile, as a small molecular, whether 1-MT was directly involved in the reversal of PTX resistance were investigated in resistant cells which was cultured alone. We will use gene chips to screen different major.genes and signaling pathways participating in 1-MT reversing resistance via enhancing T cell function, stimulating release of cytokines and direct way, in order to map the signal pathways and elucidate the molecular mechanisms.

1-MT是吲哚胺2,3-双加氧酶(IDO)抑制剂，通过改善肿瘤微环境IDO高表达导致的T细胞“失能”发挥抗肿瘤作用。近年发现IDO高表达能激活肿瘤细胞内某些分子信号通路及膜分子转运改变肿瘤生物学特性，其中包括与化疗耐药密切相关的JNK和Wnt通路；而前期研究发现耐药肿瘤细胞IDO呈高表达。本研究将1-MT及紫杉醇(PTX)联合应用于高表达和低表达IDO的乳腺癌/PTX耐药细胞与T细胞的直接共培养及Transwell共培养体系以探讨1-MT逆转PTX耐药是否依赖于增强T细胞功能或促细胞因子释放而实现，应用细胞因子抗体芯片筛选其中的关键细胞因子；将1-MT应用于耐药细胞单独培养体系探讨1-MT作为小分子物质能否直接逆转PTX耐药及直接逆转作用与IDO表达的关系。应用基因芯片筛选在增强T细胞活性、促细胞因子释放及直接作用三种途径下参与1-MT逆转耐药的不同关键基因并绘制信号网络图，阐明分子机制。

1-MT是吲哚胺2,3-双加氧酶(IDO)抑制剂，通过改善肿瘤微环境IDO高表达导致的T细胞“失能”发挥抗肿瘤作用。近年发现IDO高表达能激活肿瘤细胞内某些分子信号通路及膜分子转运改变肿瘤生物学特性，其中包括与化疗耐药密切相关的Wnt通路等；而前期研究发现耐药肿瘤细胞IDO呈高表达。本研究首先从临床研究证实乳腺癌患者化疗前血液IDO活性及肿瘤组织IDO表达水平与新辅助化疗效果及预后相关，可以为临床预测化疗是否敏感及患者预后提供一定信息。通过构建乳腺癌耐药细胞系，证实了在乳腺癌MCF-7/PTX、 MDA-MB-231/PTX 及SKBR-3/PTX耐药活性细胞中，IDO的蛋白表达、IDO活性及mRNA-IDO均是升高的。通过将CD3+T细胞及耐药细胞进行直接共培养及Transwell共培养体系发现，1-MT的应用能够增强PTX的抑制率，逆转化疗耐药。在不依赖CD3+T细胞的情况下IDO抑制剂1-MT可以增加PTX对乳腺癌耐药细胞MDA-MB-231/PTX的抑制率)，Western blot及PCR检测发现IDO抑制剂逆转耐药组中AhR、Notch-1、Notch-3蛋白呈现差异表达。经1-MT治疗后，乳腺癌耐药细胞中AhR、Notch-1、Notch-3表达下降。证实1-MT的应用能够通过影响耐药细胞免疫微环境及肿瘤细胞自身IDO/AHR/Notch通路逆转化疗耐药，提高化疗疗效，为乳腺癌化疗耐药的治疗提供新的方向。