MicroRNA-375在非小细胞肺癌发生脑转移中的作用和机制研究

The crosstalk between tumor cells and microenvironment promotes brain metastasis in non-small cell lung cancer (NSCLC). The lack of reliable diagnostic markers at the early stage of NSCLC prevents the patients from receiving early therapies. The microenvironment-induced brain metastasis is regulated by microRNAs(miRNAs). Increasing evidences have demonstrated that miR-375 is an important cancer-related miRNA in NSCLC. Our previous study has demonstrated that down-regulated miR-375 is an early predictive biomarker and an independent prognosis factor in NSCLC brain metastasis. VEGF and MMP-9 are over-expressed in brain metastases with low miR-375 expression. Down-regulation of miR-375 promoted the proliferation, invasion, migration and initial angiogenesis of NSCLC A549 cells. The overall response rate of Bevacizumab treatment, which targets VEGF, was 61.2% in intracranial lesions in a clinical trial of NSCLC. All of these evidences support the hypothesis that down-regulated miR-375 reinforces brain metastasis in NSCLC via angiogenesis pathway. In this project, we will construct the miRNA-375 lentiviral expression vector and stably transfect it into NSCLC PC14 cells to evaluate the role of miR-375 in biological properties of PC14 cells. The expression of miR-375 will be assessed in PC14/B cells, a specific brain metastasis PC14 cell line, to investigate the possible mechanisms of miR-375-induced brain metastasis in vitro. Animal models of NSCLC brain metastasis containing miR-375 sensor or inhibitory sequences will be constructed to study the mechanisms of miR-375-induced brain metastasis in vivo. Down-regulation of miR-375 may be a potential biomarker for characterizing NSCLC brain metastasis and stratifying the high-risk patients. Moreover, our data will recommend that miR-375 may serve as a new therapeutic target for NSCLC.

非小细胞肺癌(NSCLC)脑转移是肿瘤细胞与肿瘤微环境相互作用的结果，早期诊断标记物的缺乏使患者不能早期治疗。微环境中microRNAs(miRNAs) 是调节脑转移的主要因子，miR-375是NSCLC中重要的miRNA。我们前期研究已证实：miR-375低表达是NSCLC脑转移的早期预测因子和独立预后因子，促进NSCLC 细胞增殖、侵袭、迁移和形成原始血管，并且miR-375低表达的脑转移瘤中VEGF、MMP-9明显高表达，结合抗血管生成药贝伐单抗脑部控制率高达61.2%，我们预测miR-375低表达可能通过血管生成途径在NSCLC脑转移中发挥作用。本项目拟通过构建含miR-375正义和抑制序列的NSCLC细胞系及特异性脑转移细胞系，在细胞水平研究miR-375在NSCLC脑转移中的作用机制，并通过构建脑转移动物模型进一步验证。本项目将为NSCLC脑转移早期诊断和治疗提供靶点。

非小细胞肺癌(NSCLC)脑转移是肿瘤细胞与肿瘤微环境相互作用的结果，早期诊断标记物的缺乏使患者不能早期治疗。微环境中microRNAs(miRNAs) 是调节脑转移的主要因子，miR-375是NSCLC中重要的miRNA。我们通过研究已证实：miR-375低表达是NSCLC脑转移的早期预测因子和独立预后因子，促进NSCLC 细胞增殖、侵袭、迁移和形成原始血管，并且miR-375低表达的脑转移瘤中VEGF、MMP-9和PD-L1明显高表达，通过构建含miR-375正义和抑制序列的NSCLC细胞系及特异性脑转移细胞系，在细胞水平研究miR-375在NSCLC脑转移中的作用机制，并通过构建脑转移动物模型进一步验证，通过研究发现miR-375低表达可能通过血管生成机制促进肿瘤增殖、侵袭和转移，另外miR-375低表达肿瘤PD-L1过表达，可能通过免疫逃逸机制促进肿瘤增殖及转移。本项目将为NSCLC脑转移早期诊断提供生物标记物，为NSCLC合并脑转移提供新的治疗策略, 提示NSCLC合并脑转移患者能从PD-1抗体联合抗血管生成药物治疗中获益。

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