Genomic Understanding Reveals the Important Role of FGFR2 as Paeoniflorin Target for Circumventing Breast Cancer Resistance to Tamoxifen

Abstract

Objectives: Paeoniflorin (PF), a compound found in Paeonia lactiflora and Paeonia suffruticosa, has anticancer potential, particularly in inhibiting migration and invasion, the resistant cancer cells hallmarks. To date, the mechanism of overcoming tamoxifen resistance in breast cancer is not yet elucidated. This research aims to explore the potential target of PF as a co-treatment for circumventing breast cancer resistance to tamoxifen with a genomic understanding-bioinformatics.

Methods: Microarray data originating from GSE67916 and GSE85871 in the NCBI GEO database was analyzed to obtain differentially expressed genes (DEGs). Further analyses were performed on DEGs using the DAVID v6.8, STRING-DB v11.0, the Cytoscape, and cBioportal. Gene expression analysis validation in breast cancer cells and tamoxifen-resistant breast cancer cells was accomplished using GEPIA and ONCOMINE databases. Survival rate analysis of selected genes was conducted using Kaplan-Meier.

Results: We obtained 175 DEGs from the two samples (tamoxifen-resistant and paeoniflorin-treated). DEG involves in 70 biological processes, 26 cellular components, and 18 molecular functions, and three pathways relevant to breast cancer. The PPI network analysis and hub genes selection obtained 10 genes with the highest degree scores. Genetic changes for selected genes, including IFNB1, CDK6, FGFR2, OAS1, BCL2, and STAT2 were found from 0.5% to 7% of the case population per patient case. Additional analysis using cBioportal revealed FGFR signaling pathway through Ras is important for the PF mechanism in circumventing breast cancer resistance to tamoxifen. ONCOMINE and GEPIA analysis emphasized the importance of selected genes in the tamoxifen-resistance mechanism.

Conclusion: PF has potential to be used as a co-treatment for circumventing breast cancer resistance to tamoxifen by targeting FGFR2 signaling, but further validation is needed.

Keywords: Bioinformatics; Paeoniflorin; breast cancer; tamoxifen resistance.

Figure 1

(A) Chemical Structure of Tamoxifen, (B) Chemical Structure of Paeoniflorin, (C) A Venn diagram of the DEGs between tamoxifen-resistant and Paeoniflorin (PF)-treated MCF-7 breast cancer cells

Figure 2

GO Enrichment Analysis on DEGs with DAVID, Consist of Biological Process, Molecular Function, and Cellular Component

Figure 3

(A). PPI network of the DEGs, as constructed by STRING-DB v11.0 (B). PPI network between hub genes and surrounding DEGs, as analyzed by CytoHubba plugin on Cytoscape 3.8.2

Figure 4

(A) Genetic Alterations of DEGs (IFNB1, CDK6, FGFR2, OAS1, BCL2, and STAT2) presented on a chart of 14 breast cancer studies (B) Oncoprint cBioportal in the 2016 BRCA study (INSERM) : Genetic alteration of selected DEGs (IFNB1, CDK6, FGFR2, OAS1, BCL2, and STAT2) in the patient population. (C). Results of DEGs analysis by cBioportal in the pathway section related to gene alteration. The results showed that DEGs are involved in the FGFR2 signaling pathway through Ras

Figure 5

(A). Validation analysis of gene expression of IFNB1, CDK6, FGFR2, OAS1, BCL2, and STAT2 in non-resistant breast cancer cells and normal cells using GEPIA. (B). Gene expression analysis of IFNB1, CDK6, FGFR2, OAS1, BCL2, and STAT2 in recurrent and non-recurrent group after treated with tamoxifen using ONCOMINE

Figure 6

Survival Rate Analysis of IFNB1, CDK6, FGFR2, OAS1, BCL2, and STAT2 in ER+ Breast Cancer and Tamoxifen-Treated Only, Using Kaplan–Meier Curve in KMPlotter

Figure 7

Proposed Molecular Mechanisms of PF in Circumventing Breast Cancer Resistance to Tamoxifen. PF inhibits the FGFR2 pathway through its downstream signaling. PF also inhibits the transcriptional activity of FGFR2 through inhibition of Notch signaling