IMR Press / FBL / Volume 29 / Issue 4 / DOI: 10.31083/j.fbl2904160
Open Access Original Research
Activation of the MEK/ERK Pathway Mediates the Inhibitory Effects of Silvestrol on Nasopharyngeal Carcinoma Cells via RAP1A, HK2, and GADD45A
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1 College of Traditional Chinese Medicine, Chongqing Medical University, 401331 Chongqing, China
2 Department of Pharmacy, Chongqing General Hospital, Chongqing University, 400014 Chongqing, China
3 Department of Pathology, Chongqing General Hospital, Chongqing University, 400014 Chongqing, China
*Correspondence: hxz5981@163.com (Xian-Zhong Han); hgltyz@163.com (Ying-Zi Tang)
Front. Biosci. (Landmark Ed) 2024, 29(4), 160; https://doi.org/10.31083/j.fbl2904160
Submitted: 7 December 2023 | Revised: 26 February 2024 | Accepted: 18 March 2024 | Published: 23 April 2024
(This article belongs to the Special Issue Molecular Diagnostics)
Copyright: © 2024 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: Nasopharyngeal carcinoma (NPC) is a malignant tumor associated with Epstein-Barr virus (EBV) infection. Chemoradiotherapy is the mainstream treatment for locally advanced NPC, and chemotherapeutic drugs are an indispensable part of NPC treatment. However, the toxic side-effects of chemotherapy drugs limit their therapeutic value, and new chemotherapy drugs are urgently needed for NPC. Silvestrol, an emerging natural plant anticancer molecule, has shown promising antitumor activity in breast cancer, melanoma, liver cancer, and other tumor types by promoting apoptosis in cancer cells to a greater extent than in normal cells. However, the effects of silvestrol on NPC and its possible molecular mechanisms have yet to be fully explored. Methods: Cell counting kit-8 (CCK-8), cell scratch, flow cytometry, 5-ethynyl-2-deoxyuridine (EdU), and Western blot (WB) assays were used to evaluate the effects of silvestrol on the cell viability, cell cycle, apoptosis, and migration of NPC cells. RNA sequencing (RNA-Seq) was used to study the effect of extracellular signal-regulated kinase (ERK) inhibitors on the cell transcriptome, and immunohistochemistry (IHC) to assess protein expression levels in patient specimens. Results: Silvestrol inhibited cell migration and DNA replication of NPC cells, while promoting the expression of cleaved caspase-3, apoptosis, and cell cycle arrest. Furthermore, silvestrol altered the level of ERK phosphorylation. The ERK-targeted inhibitor LY3214996 attenuated silvestrol-mediated inhibition of NPC cell proliferation but not migration. Analysis of RNA-Seq data and WB were used to identify and validate the downstream regulatory targets of silvestrol. Expression of GADD45A, RAP1A, and hexokinase-II (HK2) proteins was inhibited by silvestrol and LY3214996. Finally, IHC revealed that GADD45A, RAP1A, and HK2 protein expression was more abundant in cancer tissues than in non-tumor tissues. Conclusions: Silvestrol inhibits the proliferation of NPC cells by targeting ERK phosphorylation. However, the inhibition of NPC cell migration by silvestrol was independent of the Raf-MEK-ERK pathway. RAP1A, HK2, and GADD45A may be potential targets for the action of silvestrol.

Keywords
nasopharyngeal carcinoma
silvestrol
apoptosis
ERK1/2
RAP1A
HK2
GADD45A
Figures
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