A systems biology approach identifies SART1 as a novel determinant of both 5-fluorouracil and SN38 drug resistance in colorectal cancer.
A systems biology approach identifies SART1 as a novel determinant of both 5-fluorouracil and SN38 drug resistance in colorectal cancer.
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DOI：
10.1158/1535-7163.mct-11-0510
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发表时间：
2012-01
影响因子：
5.7
通讯作者：
Johnston PG
中科院分区：
文献类型：
--
作者：
Allen WL;Stevenson L;Coyle VM;Jithesh PV;Proutski I;Carson G;Gordon MA;Lenz HJ;Van Schaeybroeck S;Longley DB;Johnston PG
晚期结直肠癌的化疗反应率仍然非常低，主要是由于耐药性，因此迫切需要改善目前的治疗策略。为了鉴定对临床相关药物5-氟尿嘧啶（5-FU）和SN 38（伊立替康的活性代谢产物）耐药的新决定因素，使用疾病特异性DNA微阵列对治疗前转移性结直肠癌活检和HCT 116亲代和化疗耐药细胞系模型进行了转录谱分析实验。为了富集潜在的化学耐药性决定基因，采用了无监督的生物信息学方法，选择了50个基因，然后使用定制设计的SiRNA筛选进行功能评估。在初步siRNA筛选中，21个基因的沉默使HCT 116细胞对5-FU或SN 38处理敏感。在一组7种CRC细胞系中选择三种基因（RAPGEF 2、PTRF和SART 1）用于进一步分析。沉默SART 1使所有7种细胞系对5-FU处理敏感，4/7种细胞系对SN 38处理敏感。然而，在更广泛的细胞系组中，RAPGEF 2或PTRF的沉默对5-FU或SN 38敏感性没有显著影响。SART 1的进一步功能分析表明，其沉默诱导的凋亡是caspase 8依赖性的。此外，SART 1的沉默导致caspase 8抑制剂c-FLIP的下调，我们之前已经证明这是结直肠癌耐药性的关键决定因素。这项研究证明了系统生物学方法用于鉴定调节耐药性的新基因的能力，并将SART 1鉴定为先前未鉴定的c-FLIP和药物诱导的caspase 8活化的调节剂。
Chemotherapy response rates for advanced colorectal cancer remain disappointingly low, primarily due to drug resistance, so there is an urgent need to improve current treatment strategies. In order to identify novel determinants of resistance to the clinically relevant drugs 5-Fluorouracil (5-FU) and SN38 (the active metabolite of irinotecan), transcriptional profiling experiments were carried out on pre-treatment metastatic colorectal cancer biopsies and HCT116 parental and chemotherapy-resistant cell line models using a disease-specific DNA microarray. To enrich for potential chemo-resistance-determining genes, an unsupervised bioinformatics approach was employed, and 50 genes were selected and then functionally assessed using custom-designed siRNA screens. In the primary siRNA screen, silencing of 21 genes sensitised HCT116 cells to either 5-FU or SN38 treatment. Three genes (RAPGEF2, PTRF and SART1) were selected for further analysis in a panel of 7 CRC cell lines. Silencing SART1 sensitised all 7 cell lines to 5-FU treatment and 4/7 cell lines to SN38 treatment. However, silencing of RAPGEF2 or PTRF had no significant effect on 5-FU or SN38 sensitivity in the wider cell line panel. Further functional analysis of SART1 demonstrated that its silencing induced apoptosis that was caspase 8-dependent. Furthermore, silencing of SART1 led to a down-regulation of the caspase 8 inhibitor, c-FLIP, which we have previously demonstrated is a key determinant of drug resistance in colorectal cancer. This study demonstrates the power of systems biology approaches for identifying novel genes that regulate drug resistance and identifies SART1 as a previously unidentified regulator of c-FLIP and drug-induced activation of caspase 8.