Estrogen Receptor Beta Influences the Inflammatory p65 Cistrome in Colon Cancer Cells

Abstract

Inflammation is a primary component of both initiation and promotion of colorectal cancer (CRC). Cytokines secreted by macrophages, including tumor necrosis factor alpha (TNFα), activates the pro-survival transcription factor complex NFκB. The precise mechanism of NFκB in CRC is not well studied, but we recently reported the genome-wide transcriptional impact of TNFα in two CRC cell lines. Further, estrogen signaling influences inflammation in a complex manner and suppresses CRC development. CRC protective effects of estrogen have been shown to be mediated by estrogen receptor beta (ERβ, ESR2), which also impacts inflammatory signaling of the colon. However, whether ERβ impacts the chromatin interaction (cistrome) of the main NFκB subunit p65 (RELA) is not known. We used p65 chromatin immunoprecipitation followed by sequencing (ChIP-Seq) in two different CRC cell lines, HT29 and SW480, with and without expression of ERβ. We here present the p65 colon cistrome of these two CRC cell lines. We identify that RELA and AP1 motifs are predominant in both cell lines, and additionally describe both common and cell line-specific p65 binding sites and correlate these to transcriptional changes related to inflammation, migration, apoptosis and circadian rhythm. Further, we determine that ERβ opposes a major fraction of p65 chromatin binding in HT29 cells, but enhances p65 binding in SW480 cells, thereby impacting the p65 cistrome differently in the two cell lines. However, the biological functions of the regulated genes appear to have similar roles in both cell lines. To our knowledge, this is the first time the p65 CRC cistrome is compared between different cell lines and the first time an influence by ERβ on the p65 cistrome is investigated. Our work provides a mechanistic foundation for a better understanding of how estrogen influences inflammatory signaling through NFκB in CRC cells.

Core Constituents of Caragana sinica Root for Rheumatoid Arthritis Treatment and the Potential Mechanism

“…Here, based on network analysis, the main targets of EAE were affiliated with the PI3K-AKT and MAPK signaling pathways, and these pathways may be involved in immune function, inflammation, and bone erosion. − Furthermore, these pathways had many intersection genes, and the NF-κB signaling pathway was one of the key overlaps among them. Activation of the PI3K-AKT and MAPK pathways can trigger the NF-κB signaling pathway. − Moreover, NF-κB plays an important role in immune function, inflammation, and cancer. − After deduction by network pharmacology, molecular docking was used to explore the potential interaction between NF-κB and key constituents. Molecular docking results indicated good ligand–receptor binding interactions between NF-κB and key constituents.…”

Delineating the role of nuclear receptors in colorectal cancer, a focused review

“…Moreover, both isoforms are reported to have different functions in CRC. For instance, ER β was reported to exhibit a protective effect in CRC through its activation by estrogen [ 305 ]. It was observed that ER β exhibited contrasting results of p65 chromatin binding in HT-29 and SW480 cells.…”

“…In HT-29 cells, ER β diminished a significant portion of p65 chromatin binding, whereas in SW480 cells, it augmented p65 binding. This could be due to the appearance of new p65 binding sites in SW480 cells in the presence of ER β , resulting in distinct modulation of the p65 cistrome in both cell lines [ 305 ].…”

Role of gonadally synthesized steroid hormones in the colorectal cancer microenvironment

“…found that 17β-estradiol induced ERβ upregulation in colon cancer cells by activating p38/MAPK signal pathway ( 44 ). ERβ regulates p65 signaling in colon cells ( 45 ). Estradiol regulates miR-135b and mismatch repair gene MMR expression in colorectal cells via ERβ ( 46 ).…”