Fiber and Healthy Fats Trigger Ferroptosis to Suppress Colon Cancer

Targeting EGFR in Myeloid Cells Rather Than Tumor Cells

Targeted therapies designed to block the epidermal growth factor receptor, known as EGFR, have long been available for specific colorectal cancer patients, particularly those without certain KRAS mutations. Yet, clinical responses vary widely, and tumors frequently develop resistance over the course of treatment. A research team led by Maria Sibilia from the Center for Cancer Research at MedUni Vienna and the Comprehensive Cancer Centre at MedUni Vienna and University Hospital Vienna investigated this therapeutic gap by examining how EGFR functions in immune cells rather than cancer cells alone, publishing their findings in the journal Cell Death & Differentiation (as reported by Medical University of Vienna).

The investigation focused on myeloid cells, a group that includes macrophages responsible for eliminating pathogens and damaged tissue. Near a tumor, however, these same cells can pivot to support cancer growth. Through preclinical models backed by modern single-cell and proteome analyses alongside patient cohort data, the team observed that silencing EGFR specifically in myeloid cells caused tumors to grow significantly more slowly. Removing EGFR strictly from the tumor cells produced no comparable therapeutic effect, indicating that anti-EGFR treatments rely heavily on altering the immune landscape inside the tumor microenvironment.

“Our results show that EGFR in myeloid cells is a key regulator of the tumor-promoting immune landscape. In this study, we discovered an unexpected mechanism underlying the therapeutic effects of anti-EGFR treatment in colorectal cancer. Rather than acting primarily via tumor cells, the results show that EGFR in myeloid cells creates a tumor-promoting microenvironment.”

Maria Sibilia, study lead at the Center for Cancer Research at MedUni Vienna

Shifting the Immune Landscape and Identifying THBS1

When the researchers silenced EGFR in myeloid cells, the production of factors that normally suppress T cells dropped. T cells act as critical defense agents capable of recognizing and destroying cancer cells, but tumor suppression often neutralizes their activity. By dampening EGFR signals in myeloid cells, the team observed a decline in specific tumor-promoting macrophages that normally build a protective barrier around cancer cells and signal a poorer prognosis (according to the Medical University of Vienna update).

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The study also highlighted the messenger protein thrombospondin-1, or THBS1, which is released by myeloid cells to interact with T cells. Data from colorectal cancer patients confirmed that elevated levels of EGFR and THBS1 correlated with poorer disease outcomes, pointing to THBS1 as a potential biomarker for tracking disease progression or tumor microenvironment characteristics.

Ferroptosis and Dietary Synergies in Colorectal Cancer Defense

While targeted therapies address immune cells in the tumor microenvironment, separate research highlights how specific nutritional combinations engage natural defense pathways. According to findings from Texas A&M AgriLife Research published by Robert Chapkin and his team, the dietary combination of high-fiber plant sources and select polyunsaturated fats—such as fish or seed oils—can destroy colorectal cancer cells through a specialized form of programmed cell death called ferroptosis (as detailed by Texas A&M AgriLife).

Chapkin, an Allen Endowed Chair and Distinguished Professor in the Texas A&M College of Agriculture and Life Sciences, noted that this pairing produces synergistic effects that surpass what either nutrient achieves independently. While fiber or fish oil consumed alone triggers standard apoptosis, ferroptosis arises exclusively from the combined intake. This mechanism targets cancer stem cells, which drive tumor development, offering a non-toxic complement to conventional treatments.

“Their effects are more than additive. They were somehow multiplying the outcomes in a way that was very provocative, and suppressed colon cancer in preclinical models.”

Robert Chapkin, Allen Endowed Chair and Distinguished Professor in Nutrition and Chronic Disease Prevention at Texas A&M University

Microbial Metabolites and the Broader Tumor Ecosystem

The broader biological landscape of colorectal cancer involves complex interactions within the gut microbiome. Colorectal cancer remains a major global health challenge, ranking as the third most commonly diagnosed cancer globally and the second in mortality, accounting for over 1.9 million new cases and approximately 900,000 deaths annually according to World Health Organization data cited in recent scientific literature (as reviewed in Frontiers in Cellular and Infection Microbiology).

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Researchers studying microbial metabolites point out that short-chain fatty acids like butyrate and propionate can suppress tumor growth by inhibiting histone deacetylases, activating G-protein-coupled receptors, and enhancing CD8+ T cell immunity. However, metabolites exhibit dual roles depending on concentration and host conditions; low levels of butyrate may promote cancer, while high concentrations suppress tumors. Secondary bile acids and lipopolysaccharides activate Wnt/β-catenin and NF-κB pathways to drive DNA damage, whereas compounds like ursodeoxycholic acid inhibit tumor growth via the GPR5-cAMP-PKA pathway.

With colorectal cancer carrying a five-year relative survival rate of 65% in the U.S. (noted in Texas A&M AgriLife reporting), integrating insights from targeted myeloid cell therapies, precision nutrition, and gut metabolite regulation offers a multi-pronged framework for future clinical strategies and biomarker development.