Indole-3-carbinol induces tumor cell death: function follows form.
Indole-3-carbinol induces tumor cell death: function follows form.
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DOI：
10.1016/j.jss.2016.04.021
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发表时间：
2016-07
期刊：
影响因子：
--
通讯作者：
Kennedy GD
中科院分区：
文献类型：
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作者：
Megna BW;Carney PR;Nukaya M;Geiger P;Kennedy GD
即使结肠镜检查和预防措施变得越来越普遍，截至2014年，结直肠癌（CRC）仍然是美国肿瘤死亡的第三大原因。许多化疗药物用于治疗结直肠癌，尽管它们通常具有显著的副作用特征或在患者特征方面的狭窄疗效范围。膳食植物化学物质，如glucobrassicin及其代谢产物吲哚-3-甲醇（I3 C）已在多种胃肠道肿瘤的许多临床前模型中参与肿瘤预防，并代表了一种有趣的新类别的CRC天然化疗药物。I3 C已被确定为芳烃受体（AHR）的配体，我们的目的是表征这种AHR激活与其细胞毒性特性的关系。用吲哚-3-甲醇或载体处理人结肠直肠癌细胞系DLD 1、HCT 116、HT-29、LS 513和RKO。通过荧光产物测定评估细胞活力，并通过与半胱天冬酶-3和半胱天冬酶-7活性的比率相关的发光信号评估凋亡活性。采用实时定量聚合酶链反应测定AHR和CYP 1A 1 mRNA的基因表达。使用在别处公开的实验室开发的转染方案在HCT 116背景上建立SiRNA稳定表达系。多种结直肠癌细胞类型在I3 C处理后表达增加的CYP 1A 1 mRNA水平（AHR驱动活性的特异性标志物），将I3 C处理表征为该途径的激动剂。此外，I3 C诱导细胞活力的剂量依赖性降低以及诱导细胞凋亡。此外，使用siRNA干扰敲低AHR反应性产生了对吲哚-3-甲醇的化疗作用的显著抗性，这涉及细胞活力和凋亡活性。吲哚-3-甲醇对结肠癌细胞的一定程度的细胞毒性和促凋亡作用依赖于芳烃受体的激活。这代表了吲哚-3-甲醇分子作用的一种新机制，并增强了我们对其在结直肠癌中作用的理解。吲哚-3-甲醇和芳烃受体途径的持续临床前研究是必要的，这可能有一天会导致新的饮食来源的结肠癌治疗，争取AHR。
Even with colonoscopy screening and preventive measures becoming more commonplace, colorectal cancer (CRC) remains the third leading cause of oncologic death in the United States as of 2014. Many chemotherapeutics exist for the treatment of colorectal cancer, though they often come with significant side effect profiles or narrow efficacy ranges in terms of patient profile. Dietary phytochemicals such as glucobrassicin and its metabolite Indole-3-carbinol (I3C) have been implicated in tumor prevention in many preclinical models across a variety of gastrointestinal tumors and represent an intriguing new class of natural chemotherapeutics for CRC. I3C has been identified as a ligand of the aryl hydrocarbon receptor (AHR), and we aimed to characterize this AHR activation in relation to its cytotoxic properties. Human colorectal cancer cell lines DLD1, HCT116, HT-29, LS513, and RKO were treated with indole-3-carbinol or vehicle. Cell viability was assessed via a fluorescent product assay, and apoptotic activity was assessed via a luminescent signal tied to a ratio of caspase-3 and caspase-7 activity. Gene expression of AHR and CYP1A1 mRNA was measured using quantitative-real time-polymerase chain reaction. SiRNA stable expression lines were established on a HCT116 background using a lab-developed transfection protocol as published elsewhere. Multiple colorectal cancer cell types express increased CYP1A1 mRNA levels (a specific marker of AHR-driven activity) following treatment with I3C, characterizing I3C treatment as agonistic of this pathway. Also, I3C induced a dose-dependent decrease in cell viability as well as inducing apoptosis. Further, using siRNA interference to knock down AHR responsiveness generated a significant resistance to the chemotherapeutic actions of indole-3-carbinol regarding both cell viability and apoptotic activity. Some degree of the cytotoxic and proapoptotic effects of indole-3-carbinol on colon cancer cells is dependent on activation of the aryl hydrocarbon receptor. This represents a novel mechanism for the molecular action of indole-3-carbinol and enhances our understanding of its effects in the context of colorectal cancer. Continued preclinical study of both indole-3-carbinol and the aryl hydrocarbon receptor pathway is warranted, which may one day lead to novel diet-derived colon cancer treatments that enlist the AHR.