Citations

Abstract The liver is organized into tightly regulated zones with distinct metabolic functions but zonation erodes with age. Cellular senescence contributes to aging and liver diseases, however, its impact on aging biology is ill-defined. As part of The Cellular Senescence Network Consortium, we used multiple spatial transcriptomics approaches (GeoMx, Visium, CosMx) with snRNA-seq to profile senescence signatures, zonation markers, and metabolic pathways in livers from wild-type (WT) mice of multiple ages. We observed a loss of canonical zone signatures in aged mouse livers characterized by “expansion” of midlobular (zone 2) marker gene expression, accompanied by diminished expression of zone 3 marker genes by middle-age (18 months), indicative of loss of cell identity. Multiple analytic approaches identified distinct age-, zone- and sex-specific senescence signatures, which were significantly associated with zonation markers changes. This was recapitulated in Ercc1 mutant models of accelerated senescence, supporting a causal role of senescent cells in liver aging. A “no-zone” hepatocyte-like cluster expanded with age and with the strongest Senescence-Associated Secretory Phenotype (SASP) profile. Gene expression profiles from senescent hepatocytes implicate decreased WNT signaling and increased BMP as contributing to age-related loss of zonation. Together, these data elucidate the role of senescent cells in driving aging biology in non-diseased liver through disruption of cell:cell signaling and the loss of metabolic and cell identity gene expression necessary for hepatocyte function.

Abstract While epoxyeicosatrienoic acids (EETs) have been implicated in breast cancer growth and progression, less is known about their effects on oncogene transcription. We have previously found that the oncogenic regioisomer (±)14,15-EET drives mitochondrial respiration, ATP synthesis, and proliferation of ER+/HER2- breast cancer cells [Cell Chem Biol. 2017 Oct 19;24(10):1259-1275]. RNAseq analysis was performed (5 replicates per condition) on serum starved (16 hours) MCF-7 cells which were then treated with (±)14,15-EET or vehicle (2 hours; serum and phenol red free medium without estradiol). Using gene set enrichment analysis (GSEA), we found that (±)14,15-EET activated an estrogen receptor alpha (ER) hallmark early response gene set and synchronously activated a MYC hallmark gene set. With activation of the MYC hallmark gene set, c-Myc gene expression was also induced at 2 hours (3.99-fold; P=2.3 x 10-17; FDR=2.8 x 10-14). These data suggest an alternative pathway for activation of estrogen and MYC regulated genes in the absence of estradiol. The 15 genes most transcriptionally activated by (±)14,15-EET at 2 hours were: VMP1, ZFP36, JUNB, FOS, IER3, EGR1, IER5L, ELF3, JUN, NR4A1, HES1, DUSP1, MYC, TOB1, and CITED2 [fold change range: 3.25 (CITED2) to 90.5 (FOS); all P< 2.86 x 10-17; all FDR < 3.03 x 10-14]. The ER regulated genes most transcriptionally activated (>1.5 fold) were: IER3, TOB1, AREG, CISH, KCNMB3, and PDK4 (fold change range: 1.77 to 4.35; P= 1.74 x 10-18 to 1.35 x 10-5; FDR=5.54 x 10-15 to 6.4 x 10-4). The MYC regulated genes most transcriptionally activated (> 1.5-fold change) were EIF4A1 (fold change= 2.37; P=1.0 x 10-7; FDR=1.33 x 10-5), IRF9 (fold change=1.58; P=0.0044; FDR= 0.026), and FOSL1 (fold change=1.51; P=0.008; FDR=0.04). Supporting the hypothesis of (±)14,15-EET activation of ER-regulated transcription, (±)14,15-EET promoted nuclear translocation of ER at 1 hour measured by DAPI normalized immunofluorescence [MCF-7 nuclear ER increase of 1.66-fold (P=0.031); ZR75-1 nuclear ER increase of 1.77-fold (P=0.015)]. Supporting the hypothesis of (±)14,15-EET activation of MYC-regulated transcription, (±)14,15-EET treatment promoted nuclear translocation of c-Myc with MCF-7 cells exhibiting a 1.22-fold increase at 2 hours (P=0.002). (±)14,15-EET also promoted nuclear translocation of FITC-70 kDa dextran with MCF-7 cells exhibiting an increase of 1.35-fold at 1 hour (P=0.029). These data suggest that (±)14,15-EET can induce an estradiol-like immediate early gene response in ER+/HER2- breast cancer cells correlating with c-Myc activation. In summary, while the effect of (±)14,15-EET on nuclear translocation may be partially cargo agnostic, (±)14,15-EET promotes ER and c-Myc nuclear translocation and associated transcription, mimicking a tandem hormonal and growth factor response. Citation Format: Jianxun Lei, Zhijun Guo, Julissa Molina-Vega, Paloma Cervantes, Swaathi Jayaraman, John R. Hawse, Carlos Perez, Juan Abrahante, Xiaojia Tang, Krishna Kalari, Jinhua Wang, John R. Falck, Carol Lange, Matthew P. Goetz, David Potter. (±) 14,15-epoxyeicosatrienoic acid induces hallmark ER and MYC gene expression and associated ER and c-Myc nuclear translocation in ER+/HER2- breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB564.