March 5, 2026 (pm/red) Researchers at the Philipps University of Marburg have identified a novel approach to treating specific, therapy-resistant forms of breast cancer – namely, hormone receptor-positive, HER2-negative breast cancer. In experimental models, they demonstrated that tumor cells which have turn into resistant to modern standard medications like CDK4/6 inhibitors develop a previously unrecognized metabolic vulnerability. This discovery offers a potential pathway for overcoming treatment resistance, a significant challenge in cancer care.
Medications such as metformin or dichloroacetate, which interfere with energy metabolism, position these cells under massive energy stress and trigger their death. The findings were published in the journal “Cell Death & Disease” by the research team led by Luise von Wichert and Dr. Niklas Gremke.
Approximately 70 percent of all breast cancer diagnoses fall into this subtype, and CDK4/6 inhibitors are now standard first-line therapy for advanced stages of the disease. This study addresses a substantial clinical need, focusing on therapies for patients who develop resistance after initially responding to treatment, explained Dr. Niklas Gremke.
Programmed Cell Death
The research centered on functionally modeling pronounced CDK4/6 inhibitor resistance under controlled laboratory conditions. Researchers systematically characterized the molecular and metabolic properties of highly resistant cell clones. This revealed a clearly defined pattern: an overactivation of the mTOR signaling pathway, inhibited autophagy – a reduced cellular recycling process – and a marked dependence on energy metabolism.
Mechanistically, the mTOR overactivation causes cells to lose their ability to compensate for energy deficiencies through autophagy. “When metabolic stress is additionally induced, for example by the drug metformin, the resistant cells respond with programmed cell death,” reported lead author Luise von Wichert, who is pursuing a doctorate at Philipps University of Marburg based on this perform.
Viewing Resistance Development as an Opportunity
“Resistance does not only imply treatment failure, but can also reveal new therapeutic vulnerabilities,” explained Dr. Niklas Gremke, a junior research group leader. Rather than viewing resistance as a nonspecific progression of the disease, the study identifies a biologically well-defined resistance subtype.
Tailored Treatment Options
In the long term, this could enable more precise examination of patients after CDK4/6 therapy fails. Physicians could better determine which patients will benefit from further treatment that specifically targets the energy metabolism of tumor cells. The study therefore contributes to more personalized cancer medicine: future therapy decisions could be based less on general standards and more on the individual characteristics of the tumor. The goal is to offer affected patients more tailored and effective treatment options.
Original publication: Luise von Wichert et al, mTOR-driven autophagy suppression defines metabolic vulnerability in CDK4/6 inhibitor-resistant HR+/HER2− breast cancer, Cell Death Dis (2026), https://doi.org/10.1038/s41419-026-08496-5
