脂代谢显像与流量测定评价SREBP1对肺癌紫杉醇耐药的调节及其分子机制

Paclitaxel, as a first-line drug of non-small cell lung carcinoma, is limited in the clinical application due to the drug resistance. As is well known, how to improve the sensitivity of paclitaxel is a key issue to address. Previous study in our team has found that abnormal lipid metabolism is related with paclitaxel resistance by metabolic flux assay. Targeting lipid metabolism is an effective way to restore the sensitivity of non-small cell lung carcinoma to paclitaxel. SREBP1, as a key regulator of de novo lipogenesis, regulates the transcription of key metabolic enzymes in the lipid metabolism. In this study, we try to reveal the relationship between chemo drug resistance and lipid metabolism and mechanism involved in lipid metabolism regulated chemoresistance. Through manipulating SREBP1 level in vivo and in vitro, we try to find out the key regulating procedure in lipid metabolism regulated chemoresistance. Finally, we will establish a system to monitor lipid metabolism via metabolic flux assay and imaging of lipid metabolism, which can be used for analyzing drug responsive, predicting chemoresistance and evaluating prognosis. This study will provide rationale and tool for paclitaxel using in personalized diagnosis and treatment of lung carcinoma.

紫杉醇作为非小细胞肺癌的一线药物，因频现耐药而限制其应用。因此，如何改善紫杉醇等化疗药物敏感性并揭示其机制尤为关键。本课题组通过代谢流量分析发现脂质代谢异常是导致肺癌耐受紫杉醇的重要原因，调节脂质代谢的核心转录因子SREBP1能有效改善紫杉醇的敏感性。SREBP1作为脂质新生关键性转录因子，能够激活多种脂质新生关键酶的表达，在肿瘤化疗耐药及恶性转归中意义重大，并已成为业界的研究热点。本研究拟用脂质代谢流量测定和代谢显像手段，比较分子生物学结果，多角度揭示肿瘤耐药与脂质代谢的内在联系及其分子机制；通过干预SREBP1基因表达、转录及修饰等，分别在离体细胞和在体动物肿瘤中探索脂质代谢与耐药产生的规律及内在调节敏感点。最终建立一套肿瘤代谢检测与显像的方法，系统评价肿瘤治疗反应、耐药预测、预后评估及可能的重要干预靶点，为肿瘤个体化诊治提供重要的科学依据及研究手段。

课题组首先建立14C-油酸、14C-葡萄糖及18F-FDG等放射性示踪方法，分别对肺癌细胞A549及紫杉醇耐药细胞A549T的代谢流量差异进行分析，发现紫杉醇耐药细胞A549T的脂肪酸分解代谢明显减低；其次，通过SREBP1 RNA干扰技术和靶向抑制剂介入试验，发现转录因子SREBP1可以通过调节脂代谢合成及分解过程，改变细胞耐药性，为靶向脂代谢调控因子SREBP1的抗肿瘤策略提供依据；最后，利用蛋白共沉淀组学技术，筛查发现蛋白质精氨酸甲基转移酶5（PRMT5）、p54nrb、MARVELD1及nBP1a / PKM2等蛋白均可通过调节SREBP1，影响脂代谢途径，改变肿瘤细胞耐药性，为临床联合开展靶向脂代谢的抗肿瘤策略提供科学依据。在研期间，在JBC、oncogene及cancer rearsch等杂志共计发表标注SCI论文18篇，培养硕士生毕业1名，博士生毕业5名。