Pineapple bromelain induces autophagy, facilitating apoptotic response in mammary carcinoma cells
Pineapple bromelain induces autophagy, facilitating apoptotic response in mammary carcinoma cells
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DOI：
10.1002/biof.121
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发表时间：
2010-11-01
期刊：
影响因子：
6
通讯作者：
Shukla, Yogeshwer
中科院分区：
文献类型：
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作者：
Bhui, Kulpreet;Tyagi, Shilpa;Shukla, Yogeshwer
菠萝蛋白酶，从菠萝，具有强大的抗癌作用。我们研究了菠萝蛋白酶作用下乳腺癌细胞（雌激素受体阳性和阴性）的自噬现象，并阐明了自噬与MCF-7细胞凋亡的关系。菠萝蛋白酶处理的MCF-7细胞表现出延迟的生长抑制反应和自噬诱导，单丹酰尸胺定位鉴定。随后是凋亡性细胞死亡，明显的亚G1期细胞分数和凋亡特征，如染色质凝聚和核分裂。3-甲基腺嘌呤（MA，自噬抑制剂）预处理降低了菠萝蛋白酶诱导的自噬水平，也导致凋亡群体的下降，表明自噬在这里促进凋亡。然而，加入caspase-9抑制剂Z-LEHD-FMK增加了自噬水平，抑制了形态学凋亡，但不能阻止细胞死亡。接下来，我们发现菠萝蛋白酶下调细胞外信号调节激酶1/2（ERK 1/2）的磷酸化，而上调c-jun N-末端激酶（INK）和p38激酶的磷酸化。此外，MA对菠萝蛋白酶抑制的ERK 1/2活化没有影响，但它下调JNK和p38活化。此外，丝裂原活化蛋白激酶（MAPK）抑制剂的加入增强了自噬率，这表明MAP激酶在菠萝蛋白酶诱导的自噬中的作用。随着时间的推移，所有三种MAPK都被不断激活。菠萝蛋白酶诱导自噬相关蛋白、轻链3蛋白B II（LC 3 BII）和beclin-1的表达。使用ERK 1/2抑制剂，LC 3BII和beclin-1的表达增加，而p38和JNK抑制剂降低这种蛋白质的表达，表明菠萝蛋白酶诱导的自噬由p38和JNK正调控，但由ERK 1/2负调控。菠萝蛋白酶的自噬诱导特性可进一步用于乳腺癌治疗。(C)2010年国际生物化学与分子生物学联合会第36卷，第6期，2010年11月/12月，第474-482页。电子邮件地址：yogeshwer_shukla@hotmail.com
Bromelain, from pineapple, possesses potent anticancer effects. We investigated autophagic phenomenon in mammary carcinoma cells (estrogen receptor positive and negative) under bromelain treatment and also illustrated the relationship between autophagy and apoptosis in MCF-7 cells. MCF-7 cells exposed to bromelain showed delayed growth inhibitory response and induction of autophagy, identified by monodansylcadaverine localization. It was succeeded by apoptotic cell death, evident by sub-G1 cell fraction and apoptotic features like chromatin condensation and nuclear cleavage. 3-Methyladenine (MA, autophagy inhibitor) pretreatment reduced the bromelain-induced autophagic level, also leading to decline in apoptotic population, indicating that here autophagy facilitates apoptosis. However, addition of caspase-9 inhibitor Z-LEHD-FMK augmented the autophagy levels, inhibited morphological apoptosis but did not prevent cell death. Next, we found that bromelain downregulated the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), whereas that of c-jun N-terminal kinase (INK) and p38 kinase were upregulated. Also, MA had no influence on bromelain-suppressed ERK1/2 activation, yet, it downregulated JNK and p38 activation. Also, addition of mitogen-activated protein kinase (MAPK) inhibitors enhanced the autophagic ratios, which suggested the role of MAP kinases in bromelain-induced autophagy. All three MAPKs were seen to be constantly activated over the time. Bromelain was seen to induce the expressions of autophagy-related proteins, light chain 3 protein B II (LC3BII), and beclin-1. Using ERK1/2 inhibitor, expressions of LC3BII and beclin-1 increased, whereas p38 and JNK inhibitors decreased this protein expression, indicating that bromelain-induced autophagy was positively regulated by p38 and JNK but negatively regulated by ERK1/2. Autophagy-inducing property of bromelain can be further exploited in breast cancer therapy. (C) 2010 International Union of Biochemistry and Molecular Biology, Inc. Volume 36, Number 6, November/December 2010, Pages 474-482. E-mail: yogeshwer_shukla@hotmail.com