Hedrich William D, Xiao Jingwei, Heyward Scott, Zhang Yao, Zhang Junran, Baer Maria R, Hassan Hazem E, Wang Hongbing
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland.
Bioreclamation IVT, Baltimore, Maryland.
Mol Cancer Ther. 2016 Mar;15(3):392-401. doi: 10.1158/1535-7163.MCT-15-0667. Epub 2016 Jan 28.
The constitutive androstane receptor (CAR and NR1i3) is a key regulator of CYP2B6, the enzyme predominantly responsible for the biotransformation of cyclophosphamide (CPA) to its pharmacologically active metabolite, 4-hydroxycyclophosphamide (4-OH-CPA). Previous studies from our laboratory illustrated that CAR activation increases the formation of 4-OH-CPA; however, CPA is rarely used clinically outside of combination therapies. Here, we hypothesize that including a selective human CAR activator with the CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) regimen can improve the efficacy without exacerbating off-target toxicity of this regimen in non-Hodgkin lymphoma treatment. In this study, we have developed a novel multiorgan coculture system containing human primary hepatocytes for hepatic metabolism, lymphoma cells as a model target for CHOP, and cardiomyocytes as a major site of off-target toxicity associated with this regimen. We found that a selective human CAR activator, CITCO (6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde-O-(3,4-dichlorobenzyl)oxime), altered expression of key drug-metabolizing enzymes and transporters in human hepatocytes, which positively affects the metabolic profile of CHOP. Coadministration of CITCO and CHOP in the coculture model led to significantly enhanced cytotoxicity in lymphoma cells but not in cardiomyocytes. Moreover, the beneficial effects of CITCO were abrogated when CAR knockout HepaRG cells were used in the coculture model. Importantly, synergistic anticancer effects were observed between CITCO and CHOP, in that inclusion of CITCO alongside the CHOP regimen offers comparable antineoplastic activity toward lymphoma cells at significantly reduced drug concentrations, and the decreased CHOP load attenuates cardiotoxicity. Overall, these findings provide a potentially promising novel strategy for facilitating CHOP-based chemotherapy.
组成型雄烷受体（CAR，即NR1i3）是细胞色素P450 2B6（CYP2B6）的关键调节因子，该酶主要负责将环磷酰胺（CPA）生物转化为其药理活性代谢物4-羟基环磷酰胺（4-OH-CPA）。我们实验室之前的研究表明，CAR激活可增加4-OH-CPA的形成；然而，CPA很少在联合治疗之外的临床中使用。在此，我们假设在CHOP（环磷酰胺、多柔比星、长春新碱和泼尼松）方案中加入一种选择性人CAR激活剂，可以提高疗效，同时在非霍奇金淋巴瘤治疗中不会加剧该方案的脱靶毒性。在本研究中，我们开发了一种新型多器官共培养系统，其中包含用于肝脏代谢的人原代肝细胞、作为CHOP模型靶点的淋巴瘤细胞以及作为与该方案相关的脱靶毒性主要部位的心肌细胞。我们发现，一种选择性人CAR激活剂CITCO（6-(4-氯苯基)咪唑并[2,1-b][1,3]噻唑-5-甲醛-O-(3,4-二氯苄基)肟）改变了人肝细胞中关键药物代谢酶和转运蛋白的表达，这对CHOP的代谢谱有积极影响。在共培养模型中同时给予CITCO和CHOP可显著增强淋巴瘤细胞的细胞毒性，但对心肌细胞无此作用。此外，当在共培养模型中使用CAR基因敲除的HepaRG细胞时，CITCO的有益作用被消除。重要的是，观察到CITCO和CHOP之间具有协同抗癌作用，即在CHOP方案中加入CITCO可在显著降低药物浓度的情况下对淋巴瘤细胞提供相当的抗肿瘤活性，并且CHOP剂量的降低减轻了心脏毒性。总体而言，这些发现为促进基于CHOP的化疗提供了一种潜在的有前景的新策略。
