J Natl Cancer Inst：天然植物化合物PEITC或可抑制乳腺癌发展

8月2日，刊登在国际著名杂志Journal of the National Cancer Institute上的一篇研究报告指出，天然的植物化合物-苯乙基异硫氰酸酯（PEITC）可以抑制小鼠模型的乳房肿瘤的生长，小鼠的乳房肿瘤和人类的乳腺癌肿瘤非常相似。食用植物可以作为化学的预防制剂，PEITC在小鼠的结肠癌、直肠癌等疾病中发挥着极强的化学预防因子的作用。

为了研究PEITC在小鼠乳房肿瘤中的作用效率，来自匹兹堡癌症研究中心的研究者给予小鼠模型两种饮食模式：一种节制饮食，另外一种为添加PEITC的饮食，持续29周时间。研究者随后进行了组织病理学的评估并且测定了小鼠机体中乳房肿瘤的尺寸、以及细胞增殖、凋亡和新生血管发生的情况。

研究者发现给予PEITC后，小鼠的乳腺肿瘤尺寸降低了56.3%，尽管添加PEITC并不能完全抵御乳房的癌变，但是饮食中添加PEITC的小鼠相比对照组，其机体表现出乳房癌的抑制现象。

研究者最后指出了他们研究的局限性，研究结果仅限于小鼠中，虽然和人类非常相似，但是还是有一些不同，而且添加PETIC和其促发癌细胞凋亡的机制关系尚不清楚。

编译自：Plant-Based Compound Slows Breast Cancer in a Mouse Model

doi:10.1093/jnci/djs321
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Biomarkers of Phenethyl Isothiocyanate-Mediated Mammary Cancer Chemoprevention in a Clinically Relevant Mouse Model

Shivendra V Singh, Su-Hyeong Kim, Anuradha Sehrawat, Julie A Arlotti, Eun-Ryeong Hahm, Kozue Sakao, Jan H Beumer, Rachel C Jankowitz, Kumar Chandra-Kuntal, Joomin Lee, Anna A Powolny and Rajiv Dhir

Background Phenethyl isothiocyanate (PEITC) is a natural plant compound with chemopreventative potential against some cancers and the ability to induce apoptosis in breast cancer cells. Methods Female mouse mammary tumor virus–neu mice were fed a control AIN-76A diet (n = 35) or the same diet supplemented with 3 µmol PEITC/g diet (n = 33) for 29 weeks, at which time they were killed. Breast tissue sections were stained with hematoxylin and eosin for histopathological assessments, and incidence and size of macroscopic mammary tumors were assessed. Cell proliferation (Ki-67 staining), apoptosis (terminal deoxynucleotidyl transferase–mediated dUTP nick-labeling), and neoangiogenesis (CD31 staining) were determined in tumor sections. Plasma levels of transthyretin were measured in treated and control mice. Expression of proteins in mammary tumor sections was determined by immunohistochemistry. Proteomic profiling was performed by two-dimensional gel electrophoresis followed by mass spectrometry. All statistical tests were two-sided. Results Administration of PEITC for 29 weeks was associated with 53.13% decreased incidence of macroscopic mammary tumors (mean tumor incidence, PEITC-supplemented diet vs control diet, 18.75% vs 40.00%, difference = –21.25%, 95% confidence interval [CI] = –43.19% to 0.69%, P = .07) and with a 56.25% reduction in microscopic mammary carcinoma lesions greater than 2mm2 (mean incidence, PEITC-supplemented diet vs control diet, 18.75% vs 42.86%, difference = –24.11%, 95% CI = –46.35% to –1.86%, P = .04). PEITC-mediated mammary cancer growth inhibition was not because of suppression of human epidermal growth factor receptor-2 expression but was associated with reduced cellular proliferation and neoangiogenesis, increased apoptosis, and altered expression of several proteins, including decreased ATP synthase in the tumor and increased plasma levels of transthyretin. Conclusions PEITC inhibits the growth of mammary cancers in a mouse model with similarities to human breast cancer progression. ATP synthase and transthyretin appear to be novel biomarkers associated with PEITC exposure.