A ROS/Akt/NF-κB Signaling Cascade Mediates Epidermal Growth Factor-Induced Epithelial-Mesenchymal Transition and Invasion in Human Breast Cancer Cells

Wei Li Min; Bao Feng Wang; Bao Bao Liang; Lun Zhang; Ji Yuan Pan; Yi Huang; Yang Zhao; Shuai Lin; Yi Han Zhao; Shu Qun Zhang; Qing Yong Ma

doi:10.14740/wjon1518

A ROS/Akt/NF-κB Signaling Cascade Mediates Epidermal Growth Factor-Induced Epithelial-Mesenchymal Transition and Invasion in Human Breast Cancer Cells

World J Oncol. 2022 Oct;13(5):289-298. doi: 10.14740/wjon1518. Epub 2022 Oct 22.

Authors

Wei Li Min^{1

2}, Bao Feng Wang^{3

2}, Bao Bao Liang¹, Lun Zhang⁴, Ji Yuan Pan³, Yi Huang⁵, Yang Zhao¹, Shuai Lin¹, Yi Han Zhao⁶, Shu Qun Zhang¹, Qing Yong Ma⁴

Affiliations

¹ Department of Oncology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710004, China.
² These authors contributed equally to this work.
³ Department of Radiation Therapy, Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710004, China.
⁴ Department of Hepatobiliary Surgery, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an 710061, China.
⁵ Department of Ultrasound, Xi'an Chest Hospital, Xi'an 710061, China.
⁶ Special Stomatology Department, College of Stomatology, Xi'an Jiaotong University, Xi'an 710004, China.

Abstract

Background: As one of the most widely used anti-diabetic drugs for type II diabetes, metformin has been shown to exhibit anti-cancer activity in recent years. Epidermal growth factor (EGF) and its receptor, EGFR, play important roles in cancer metastasis in various tumors, including breast cancer. Epithelial-mesenchymal transition (EMT) is a critical process for cancer invasion and metastasis. In this study, we use EGF as a metastatic inducer to investigate the effect of metformin on cancer cell migration, invasion and EMT.

Methods: Human breast cancer MCF-7 cells were exposed to EGF with or without metformin or N-acetyl cysteine (NAC). The effects of metformin on breast cancer cell proliferation were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The production of reactive oxygen species (ROS) was tested using 2,7-dichlorodihydrofluorecein diacetate (DCFH-DA). The migratory and invasive abilities of tumor cells were analyzed using wound healing assay and transwell invasion assay, respectively. The expressions of E-cadherin, N-cadherin and Snail were tested using real-time quantitative polymerase chain reaction (qRT-PCR) and western blotting at mRNA and protein levels. The activation of protein kinase B (Akt) and nuclear factor kappa B (NF-κB) were measured by western blotting.

Results: Our results showed that metformin inhibited breast cancer cell proliferation in a dose-dependent manner with or without EGF. EGF-induced alterations in cell morphology that are characteristic of EMT were reversed by metformin. Metformin also inhibited the EGF-modulated expression of E-cadherin, N-cadherin and Snail and further suppressed cell invasion and migration. In addition, metformin suppressed EGF-induced phosphorylation of Akt and NF-κB. ROS is involved in EGF-induced cancer invasion and activation of phosphatidylinositol 3-kinase (PI3K)/Akt/NF-κB pathway.

Conclusion: Taken together, these data indicate that metformin suppresses EGF-induced breast cancer cell migration, invasion and EMT through the inhibition of the PI3K/Akt/NF-κB pathway. These results provide a novel mechanism to explain the role of metformin as a potent anti-metastatic agent in breast cancer cells.

Keywords: Breast cancer; EGF; EMT; Metformin; PI3K/Akt.