Cancer Bioimmunotherapy Unit, Centro di Riferimento Oncologico, Istituto di Ricovero e Cura a Carattere Scientifico, Aviano, Italy.
Br J Cancer. 2012 Sep 25;107(7):1116-24. doi: 10.1038/bjc.2012.361. Epub 2012 Aug 21.
Epigenetic remodelling of cancer cells is an attractive therapeutic strategy and distinct DNA hypomethylating agents (DHA) are being actively evaluated in patients with hemopoietic or solid tumours. However, no studies have investigated the modulation of gene expression profiles (GEP) induced by DHA in transformed and benign tissues. Such information is mandatory to clarify the fine molecular mechanism(s) underlying the clinical efficacy of DHA, to identify appropriate therapeutic combinations, and to address safety issues related to their demethylating potential in normal tissues. Thus, utilising a syngeneic mouse model, we investigated the remodelling of GEP of neoplastic and normal tissues induced by systemic administration of DHA.
The murine mammary carcinoma cells TS/A were injected s.c. into female BALB/c mice that were treated i.p. with four cycles of the DHA 5-aza-2'-deoxycytidine (5-AZA-CdR) at a fractioned daily dose of 0.75 mg kg(-1) (q8 h × 3 days, every week). Whole mouse transcriptomes were analysed by microarrays in neoplastic and normal tissues from control and treated mice. Results were processed by bioinformatic analyses.
In all, 332 genes were significantly (P ≤ 0.05; FC ≥ 4) modulated (294 up and 38 downregulated) in neoplastic tissues from 5-AZA-CdR-treated mice compared with controls. In decreasing order of magnitude, changes in GEP significantly (P ≤ 0.05) affected immunologic, transport, signal transduction, spermatogenesis, and G-protein-coupled receptor protein signalling pathways. Epigenetic remodelling was essentially restricted to tumour tissues, leaving substantially unaltered normal ones.
The ability of 5-AZA-CdR to selectively target tumour GEP and its major impact on immune-related genes, strongly support the clinical use of DHA alone or combined with immunotherapeutic agents.
对癌细胞进行表观遗传重塑是一种有吸引力的治疗策略，目前正在对血液系统或实体肿瘤患者进行不同的 DNA 低甲基化药物（DHA）的积极评估。然而，尚无研究调查 DHA 在转化和良性组织中诱导的基因表达谱（GEP）的调节。此类信息对于阐明 DHA 临床疗效的精细分子机制、识别合适的治疗组合以及解决与正常组织去甲基化潜力相关的安全性问题是必需的。因此，我们利用同源小鼠模型研究了 DHA 全身给药对肿瘤和正常组织 GEP 的重塑。
将小鼠乳腺肿瘤细胞 TS/A 皮下注射到雌性 BALB/c 小鼠中，然后用每日分次剂量为 0.75mg/kg（q8 h×3 天，每周一次）的 DHA 5-氮杂-2'-脱氧胞苷（5-AZA-CdR）腹腔内治疗 4 个周期。通过微阵列分析对照和治疗小鼠的肿瘤和正常组织中的全鼠转录组。通过生物信息学分析处理结果。
与对照组相比，5-AZA-CdR 治疗的小鼠肿瘤组织中有 332 个基因（P≤0.05；FC≥4）显著（P≤0.05；FC≥4）调节（294 个上调，38 个下调）。按幅度递减顺序，GEP 的变化显著（P≤0.05）影响免疫、转运、信号转导、精子发生和 G 蛋白偶联受体蛋白信号通路。表观遗传重塑主要局限于肿瘤组织，基本不改变正常组织。
5-AZA-CdR 选择性靶向肿瘤 GEP 的能力及其对免疫相关基因的主要影响，强烈支持单独使用 DHA 或与免疫治疗药物联合使用。
