University of Michigan Rogel Cancer Center researchers have unveiled a groundbreaking metabolic mechanism that colorectal cancer cells exploit to maintain exceptionally high iron levels, a discovery that opens promising avenues for targeted cancer therapies. Published recently in Cell Metabolism, this study provides an unprecedented insight into how tumor cells sidestep iron toxicity and evade a form of cell death known as ferroptosis, potentially revolutionizing the understanding of metal metabolism in cancer biology.

Colorectal cancer cells are known to harbor elevated iron concentrations, far surpassing those found in healthy cells. Iron is a double-edged sword in cellular physiology—essential for processes like DNA synthesis and cell proliferation but lethal in excess due to its propensity to generate harmful reactive oxygen species. Ordinarily, cells with excessive iron succumb to ferroptosis, a specialized form of oxidative cell death driven by iron-mediated lipid peroxidation. Tumor cells subvert this natural safeguard, sustaining iron overload without triggering their own demise, but how they achieve this has remained elusive—until now.

The investigative team led by Dr. Yatrik Shah, Horace W. Davenport Collegiate Professor of Physiology at Michigan Medicine, employed a metabolism-directed CRISPR screening approach to systematically dissect the pathways protecting colorectal cancer cells from iron-induced oxidative damage. Surprisingly, canonical ferroptotic enzymes, previously presumed central to this resistance, were found non-essential for tumor survival. This redirected focus led the scientists to explore mitochondrial metabolism more profoundly.

Their research unveiled that the mitochondrial enzyme complex II plays a pivotal role in safeguarding cancer cells from iron-induced toxicity. Complex II regulates coenzyme Q (CoQ) within mitochondria, a key antioxidant molecule that quells oxidative stress. By fine-tuning CoQ’s redox state, complex II effectively buffers the destructive potential of accumulated iron, preventing ferroptosis and enabling cancer cell proliferation. When researchers knocked out complex II in colorectal cancer models, iron toxicity became unmanageable for the tumor cells, leading to widespread cell death and marked tumor growth inhibition.

Crucially, complex II’s protective mechanism appears specific to the high-iron environment of cancer cells. In mouse models, disruption of complex II elicited negligible adverse effects on normal tissues, underscoring the therapeutic potential of selectively targeting this mitochondrial axis in colorectal cancer. This specificity addresses a significant hurdle in oncology: minimizing treatment toxicity while maximizing antitumor efficacy.

Further intricacies emerged as the study revealed a feedback loop wherein iron itself modulates complex II activity, suggesting a sophisticated regulatory axis that maintains iron homeostasis within tumors. This bidirectional interaction offers additional molecular targets for disrupting iron tolerance in cancer cells and deepening our understanding of tumor metabolism.

These findings represent a paradigm shift from earlier hypotheses centered on canonical ferroptosis regulators, highlighting the necessity of focusing on mitochondrial metabolism in cancer research. By leveraging sophisticated genome-editing tools and bioenergetic profiling, the Rogel Cancer Center team charted a novel course for drug discovery efforts aimed at crippling iron addiction—a hallmark of not only colorectal but potentially many other malignancies.

The next phase of this research endeavors to identify and develop potent inhibitors of complex II or its associated metabolic pathways. Given that dysregulated iron metabolism is a common vulnerability across diverse cancer types, these interventions could herald a new era of broad-spectrum anticancer strategies. Moreover, detailed characterization of iron complex II interplay might uncover additional metabolic dependencies exploitable for therapeutic gains.

This transformative research underscores the intricate metabolic adaptations that empower colorectal cancers to circumvent intrinsic iron toxicity constraints. By illuminating the heme-complex II axis as a linchpin in maintaining oxidative balance amid iron overload, it offers a highly selective target for the design of next-generation anticancer agents.

Researchers anticipate that combining complex II inhibition with other therapies may amplify treatment responses and overcome resistance mechanisms. As the quest to outsmart cancer evolves, this study reinforces the vital role of mitochondrial metabolism understanding in crafting innovative clinical interventions.

In sum, the University of Michigan team’s discovery of complex II’s role in buffering iron toxicity not only deciphers a long-standing biological enigma but also charts a compelling translational pathway. It epitomizes how fundamental metabolic insights can accelerate the development of precision treatments conferring hope to millions affected by colorectal cancer worldwide.

Subject of Research: Cells
Article Title: Iron addicted colorectal cancers exploit heme-complex II axis to resist oxidative cell death
News Publication Date: June 17, 2026
Web References: http://dx.doi.org/10.1016/j.cmet.2026.04.020
References: “Iron addicted colorectal cancers exploit heme-complex II axis to resist oxidative cell death,” Cell Metabolism, DOI: 10.1016/j.cmet.2026.04.020
Image Credits: Shah Lab, Rogel Cancer Center
Keywords: Colorectal cancer, iron metabolism, ferroptosis, complex II, coenzyme Q, mitochondrial metabolism, oxidative cell death, tumor metabolism, cancer therapy

Ebola Virus Finds Sanctuary in the Brain: Breaking Ground with Human Cerebral Organoids

In a landmark study published in Nature Microbiology, researchers from the Icahn School of Medicine at Mount Sinai and the Bernhard Nocht Institute for Tropical Medicine (BNITM) have uncovered how the deadly Ebola virus can persist and replicate stealthily within the human central nervous system. By leveraging cutting-edge cerebral organoid models—three-dimensional brain-like structures derived from human pluripotent stem cells—the team has shed light on the viral mechanisms that allow long-term survival, raising critical implications for treatment and prevention strategies of Ebola virus disease (EVD).

It has long been a harrowing clinical observation that survivors of acute Ebola infections sometimes suffer relapses or develop inflammatory syndromes months or even years after recovery. This enduring threat is attributed to the virus’s ability to hide out in “immune-privileged” regions of the body—such as the central nervous system (CNS)—where the immune surveillance is deliberately restrained to protect vulnerable tissue from damaging inflammation. This latest research elucidates the ways Ebola virus exploits this sanctuary and endures prison-like conditions inside cerebral tissue without fully succumbing to immune clearance.

The team engineered cerebral organoids by coaxing human induced pluripotent stem cells (iPSCs) into forming spherical, differentiated structures composed of multiple neural cell types: neurons, astrocytes, and microglia alike. These organoids mimic the cellular environment of the human brain closely enough to serve as a viable model to explore viral persistence with unprecedented resolution and relevance. Unlike traditional animal models, these human-derived organoids enable direct examination of host-virus interactions in a context that recapitulates human neuroanatomy and immunology.

Longitudinal infection experiments revealed that Ebola virus and related filoviruses—including Sudan, Reston, and Marburg viruses—could sustain active replication within these cerebral organoids for up to 120 days. More intriguingly, Ebola virus infected not just neurons but also astrocytes and microglia, the brain’s resident immune cells. The virus exhibited two spreading modalities: direct cell-to-cell contact transmission as well as classical budding from host cells. This productive persistence clearly places the virus in an infectious, replicative state rather than a latent or inactive one.

Despite the robust production of pro-inflammatory cytokines by infected organoids, the innate immune responses orchestrated within this model failed to clear the infection entirely. The study observed an upregulation of immune and inflammatory markers at later stages, mirroring clinical presentations seen in Ebola virus disease survivors who develop delayed meningoencephalitis and other inflammatory sequelae. The data affirm that persistent filovirus infection in immune-privileged tissues contributes to localized inflammation, fostering neurological disease conditions even after primary viremia subsides.

At the molecular level, whole-genome sequencing of viral populations recovered from persistently infected organoids uncovered the presence of defective viral genomes (DVGs) and a spectrum of mutations emerging during chronic replication. DVGs are truncated or mutated forms of viral genomes known to modulate replication dynamics and immune evasion in other viral families. These defective genomes may allow the Ebola virus to dampen replication while maintaining a foothold inside host tissue, facilitating long-term survival without triggering overwhelming immune destruction.

Several mutations identified in the viral sequences corresponded to variants previously reported to attenuate replication in natural infections, while others were novel and uncharacterized. This emerging mutational landscape hints at an ongoing evolutionary arms race as the virus adapts to the CNS environment and immune pressures. Such adaptations could be critical determinants in the capacity of Ebola virus to establish persistent reservoirs and cause relapses.

This cerebral organoid model’s faithful recapitulation of human Ebola virus infection patterns underscores its utility as a powerful platform for mechanistic studies of viral persistence. Unlike animal models, which often fail to mimic intricate human neural immunology adequately, organoids offer a nearer-to-human experimental system. This breakthrough has potential ramifications for testing and optimizing targeted antiviral therapies aimed specifically at reservoirs residing in immune-privileged compartments.

Moreover, cerebral organoids provide an ethically favorable and scalable alternative to animal experiments, fostering more humane and potentially faster progress in infectious disease research. This innovation aligns with global efforts to reduce animal use in biomedical studies and to increase translational fidelity to human conditions.

Looking ahead, the research team emphasizes expanding their investigations to include other lesser-studied filoviruses such as Taï Forest, Bombali, and Bundibugyo viruses. Comprehensive deciphering of host–virus dynamics in such a model may unravel universal persistence mechanisms across filovirus species, informing cross-cutting therapeutic strategies. Crucially, this work also lays groundwork for exploring how viral persistence in the CNS intersects with immune modulation, neuroinflammation, and long-term neurological sequelae in EVD survivors.

Persistent Ebola infection in the brain highlights a formidable challenge for public health, given the potential for virus reactivation or even transmission from immune-privileged sanctuaries. This study delivers a compelling window into that hidden battleground, leveraging state-of-the-art human cellular models to confront a deadly pathogen’s stealth strategies. Unlocking the biology of Ebola’s cerebral persistence may ultimately pave the way for interventions that not only save lives during acute infection but also circumvent post-recovery complications and community outbreaks.

As our understanding deepens, harnessing cerebral organoids as investigative tools promises to revolutionize the study of neurotropic viral infections. The Mount Sinai and BNITM collaboration exemplifies how multidisciplinary, translational research can illuminate the dark corners of viral pathogenesis and guide clinical innovation for diseases once deemed intractable.

Subject of Research: Animals (via human-derived cerebral organoids)

Article Title: Host–virus determinants of Ebola virus persistence in a human cerebral organoid model

News Publication Date: 12-Jun-2026

Web References:
https://www.nature.com/articles/s41564-026-02388-2
http://dx.doi.org/10.1038/s41564-026-02388-2

Keywords: Ebola virus, cerebral organoids, central nervous system, viral persistence, filoviruses, neuroinflammation, antiviral therapy, immune evasion, defective viral genomes, virus-host interaction