Loss of NFE2L3 protects against inflammation-induced colorectal cancer through modulation of the tumor microenvironment

Abstract

We investigated the role of the NFE2L3 transcription factor in inflammation-induced colorectal cancer. Our studies revealed that Nfe2l3−/− mice exhibit significantly less inflammation in the colon, reduced tumor size and numbers, and skewed localization of tumors with a more pronounced decrease of tumors in the distal colon. CIBERSORT analysis of RNA-seq data from normal and tumor tissue predicted a reduction in mast cells in Nfe2l3−/− animals, which was confirmed by toluidine blue staining. Concomitantly, the transcript levels of Il33 and Rab27a, both important regulators of mast cells, were reduced and increased, respectively, in the colorectal tumors of Nfe2l3−/− mice. Furthermore, we validated NFE2L3 binding to the regulatory sequences of the IL33 and RAB27A loci in human colorectal carcinoma cells. Using digital spatial profiling, we found that Nfe2l3−/− mice presented elevated FOXP3 and immune checkpoint markers CTLA4, TIM3, and LAG3, suggesting an increase in Treg counts. Staining for CD3 and FOXP3 confirmed a significant increase in immunosuppressive Tregs in the colon of Nfe2l3−/− animals. Also, Human Microbiome Project (HMP2) data showed that NFE2L3 transcript levels are higher in the rectum of ulcerative colitis patients. The observed changes in the tumor microenvironment provide new insights into the molecular differences regarding colon cancer sidedness. This may be exploited for the treatment of early-onset colorectal cancer as this emerging subtype primarily displays distal/left-sided tumors.

Multi-Omics Analysis of Molecular Characteristics and Carcinogenic Effect of NFE2L3 in Pan-Cancer

“…With the continuous development of biomedical technology, tumor immunotherapy has become the fourth most effective treatment method after surgery, chemotherapy, and radiotherapy (Dou et al, 2022;Saliba et al, 2022). The potential of NFE2L3 in tumor immunotherapy was explored further by conducting a correlation analysis between the expression of NFE2L3 and immune characteristics.…”

“…NFE2L3 was observed to be involved in transcriptional regulation and chromatin remodeling of the RNA polymerase II promoter in response to oxidative stress by GO enrichment analysis. Moreover, Saliba et al (2022) found that knockdown of NFE2L3 could prevent inflammation-induced colorectal cancer by regulating the tumor microenvironment. NFE2L3 was identified to be involved in multiple immune pathways in most tumors using GSEA analysis, including: CD22 mediated BCR regulation, FCGR activation, and the creation of C4 and C2 activators.…”

“…Previous studies have demonstrated that NFE2L3 plays an important role in inflammation and is identified as a stemness marker gene as it is upregulated in the early stage of stem cell differentiation (Witschi et al, 1989;Braun et al, 2002;Byrne et al, 2007;Ben-Yehudah et al, 2010). Studies have also shown that NFE2L3 is closely related to the development and progression of tumors (Saliba et al, 2022). Knockdown of NFE2L3 showed a tumor-suppressive effect in liver and gastric cancer cells (Yu et al, 2019;Wang et al, 2021).…”

The role of the tumor microenvironment in colorectal cancer and the potential therapeutic approaches

“…One of the most important promoters of tumorigenesis in colon cancer is inflammation 53 . Inflammation starts as a response of the immune system to pathogens or tissue damage; however, perpetuating this response results in increasing the incidence of cancer due to the weakness of the anti‐tumor response because it can release bioactive molecules from tumor microenvironment cells such as chemokines, cytokines, and growth factors—that contribute to constant proliferation and cell survival signals to prevent apoptosis‐metalloproteinases,—as a modifier of extracellular matrix to initiate epithelial‐mesenchymal transition (EMT)—pro‐angiogenic factors, and it can also facilitate other tumorigenesis mechanisms such as genome instability 34,54,55 . Although fibroblasts, immune cells, and endothelial cells produce a large portion of pro‐inflammatory signals as tumor microenvironment components, they have also been shown to play an important role in tumorigenesis promotion through the secretion of cytokines and proteases from CAFs 34 …”

“…VEGF, vascular endothelial growth factor; HIF1, hypoxiainducible factor-1; TGFβ, transforming growth factor-beta; ECM, extracellular matrix; MMPs, matrix metalloproteinases; RBC, red blood cell (EMT)-pro-angiogenic factors, and it can also facilitate other tumorigenesis mechanisms such as genome instability. 34,54,55 Although fibroblasts, immune cells, and endothelial cells produce a large portion of pro-inflammatory signals as tumor microenvironment components, they have also been shown to play an important role in tumorigenesis promotion through the secretion of cytokines and proteases from CAFs. 34 It has been shown that fibroblasts adjacent to the CRC cells express IL-6, FAPα, and SPINK3 as an inflammation-induced factor in CRC.…”