ERα 通过 DNMT1/ISL1/ERK 轴抑制 OCT4 诱导的乳腺癌细胞增殖是必需的。

ERα is required for suppressing OCT4-induced proliferation of breast cancer cells via DNMT1/ISL1/ERK axis.

机构信息

The Key Laboratory of Pathology, Ministry of Education, College of Basic Medical Science, Jilin University, Changchun, China.

出版信息

Cell Prolif. 2019 Jul;52(4):e12612. doi: 10.1111/cpr.12612. Epub 2019 Apr 22.

DOI:10.1111/cpr.12612

PMID:31012189

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC6668970/

Abstract

OBJECTIVE

POU5F1 (OCT4) is implicated in cancer stem cell self-renewal. Currently, some studies have shown that OCT4 has a dual function in suppressing or promoting cancer progression. However, the precise molecular mechanism of OCT4 in breast cancer progression remains unclear.

MATERIALS AND METHODS

RT-PCR and Western blot were utilized to investigate OCT4 expression in breast cancer tissues and cells. Cell proliferation assays and mouse models were applied to determine the effects of OCT4 on breast cancer cell proliferation. DNMT1 inhibitors, ChIP, CoIP, IHC and ERα inhibitors were used to explore the molecular mechanism of OCT4 in breast cancer.

RESULTS

OCT4 was down-regulated in breast cancer tissues, and the overexpression of OCT4 promoted MDA-MB-231 cell proliferation and inhibited the proliferation of MCF-7 cells in vitro and in vivo, respectively. Two DNMT1 inhibitors (5-aza-dC and zebularine) suppressed OCT4-induced MDA-MB-231 cell proliferation through Ras/Raf1/ERK inactivation by targeting ISL1, which is the downstream of DNMT1. In contrast, OCT4 interacted with ERα, decreased DNMT1 expression and inactivated the Ras/Raf1/ERK signalling pathway in MCF-7 cells. Moreover, ERα inhibitor (AZD9496) reversed the suppression of OCT4-induced proliferation in MCF-7 cells via the activation of ERK signalling pathway.

CONCLUSIONS

OCT4 is dependent on ERα to suppress the proliferation of breast cancer cells through DNMT1/ISL1/ERK axis.

摘要

目的

POU5F1（OCT4）被认为与癌症干细胞自我更新有关。目前，一些研究表明 OCT4 在抑制或促进癌症进展方面具有双重功能。然而，OCT4 在乳腺癌进展中的精确分子机制仍不清楚。

材料和方法

利用 RT-PCR 和 Western blot 检测乳腺癌组织和细胞中 OCT4 的表达。通过细胞增殖实验和小鼠模型研究 OCT4 对乳腺癌细胞增殖的影响。利用 DNMT1 抑制剂、ChIP、CoIP、IHC 和 ERα 抑制剂来探讨 OCT4 在乳腺癌中的分子机制。

结果

OCT4 在乳腺癌组织中表达下调，过表达 OCT4 分别促进 MDA-MB-231 细胞的增殖，抑制 MCF-7 细胞的增殖，在体外和体内。两种 DNMT1 抑制剂（5-aza-dC 和 zebularine）通过靶向 DNMT1 的下游 ISL1，抑制 OCT4 诱导的 MDA-MB-231 细胞增殖，从而使 Ras/Raf1/ERK 失活。相反，OCT4 与 ERα 相互作用，降低 DNMT1 的表达，并在 MCF-7 细胞中使 Ras/Raf1/ERK 信号通路失活。此外，ERα 抑制剂（AZD9496）通过激活 ERK 信号通路逆转了 OCT4 诱导的 MCF-7 细胞增殖的抑制。