Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Keelung 204, Taiwan; Department of Medicine, College of Medicine, Chang Gung University, Kwei-Shan, Taoyuan, 259, Taiwan.
Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Keelung 204, Taiwan.
Taiwan J Obstet Gynecol. 2023 Nov;62(6):874-883. doi: 10.1016/j.tjog.2023.06.001.
The data on the association between phthalates and breast cancer risk remains inconsistent. This study aimed to explore the possible mechanism of low-dose exposures of phthalates, including Butyl benzyl phthalate (BBP), di(n-butyl) phthalate (DBP), and di(20ethylhexyl) phthalate (DEHP), on breast tumorigenesis.
MCF-10A normal breast cells were treated with phthalates (10 and 100 nM) and 17β-estradiol (E, 10 nM), which were co-cultured with fibroblasts from normal mammary tissue. Cell viability, cycle, and apoptosis were detected by MTT assay, flow cytometry, and TUNEL assay respectively. The expression levels of related proteins were determined by Western blot.
Like E, both 10 nM and 100 nM phthalates exerted significantly higher cell viability, lower apoptosis, and increased cell numbers in the S and G2/M phases with up-regulation of cyclin D/CDK4, cyclin E/CDK2, cyclin A/CDK2, cyclin A/CDK1, and cyclin B/CDK1, compared with the control group. Significant increase in PDK1, P13K, p-AKT, p-mTOR, and BCL-2 expression and a decrease in Bax protein, cytochrome C, caspase 8, and caspase 3 levels were noted in cells treated with 10 nM and 100 nM phthalates and E2, compared with the control group and MCF-10A cells co-cultured with fibroblasts. The effects of the three phthalates were noted to be dose-dependent.
The results indicate that phthalates at a level below its no-observed-adverse-effect concentration, as defined by the current standards, still induce cell cycle progression and proliferation as well as inhibit apoptosis of normal breast cells. Thus, the possibility of breast tumorigenesis through chronic phthalate exposure should be considered.
邻苯二甲酸酯与乳腺癌风险之间的关联数据仍然不一致。本研究旨在探讨邻苯二甲酸酯（包括邻苯二甲酸丁基苄基酯（BBP）、邻苯二甲酸二正丁酯（DBP）和邻苯二甲酸二（2-乙基己基）酯（DEHP））低剂量暴露于乳腺癌发生的可能机制。
用邻苯二甲酸（10 和 100 nM）和 17β-雌二醇（E，10 nM）处理 MCF-10A 正常乳腺细胞，并与正常乳腺组织成纤维细胞共培养。分别通过 MTT 测定法、流式细胞术和 TUNEL 测定法检测细胞活力、周期和凋亡。通过 Western blot 测定相关蛋白的表达水平。
与 E 相似，10 nM 和 100 nM 邻苯二甲酸均显著提高细胞活力，降低细胞凋亡，增加 S 和 G2/M 期细胞数量，上调细胞周期蛋白 D/CDK4、细胞周期蛋白 E/CDK2、细胞周期蛋白 A/CDK2、细胞周期蛋白 A/CDK1 和细胞周期蛋白 B/CDK1，与对照组相比。与对照组和与成纤维细胞共培养的 MCF-10A 细胞相比，用 10 nM 和 100 nM 邻苯二甲酸和 E2 处理的细胞中 PDK1、PI3K、p-AKT、p-mTOR 和 BCL-2 的表达显著增加，Bax 蛋白、细胞色素 C、半胱天冬酶 8 和半胱天冬酶 3 的水平降低。三种邻苯二甲酸的作用呈剂量依赖性。
结果表明，在目前标准定义的无观察不良效应浓度以下，邻苯二甲酸仍能诱导正常乳腺细胞的细胞周期进程和增殖，并抑制细胞凋亡。因此，应考虑通过慢性邻苯二甲酸暴露引起乳腺癌发生的可能性。
