How Prostate Cancer Hijacks Amino Acids to Beat Hormone Therapy

Prostate cancer cells can outsmart hormone therapy by rewiring how they use nutrients, and a new preclinical study from Weill Cornell Medicine shows exactly how. Published in Nature Metabolism, the work reveals that tumors hijack the metabolism of two common amino acids, isoleucine and valine, to boost cholesterol production inside the tumor. That extra cholesterol is then converted into androgens, the very hormones that standard treatments try to block, allowing the cancer to keep growing despite therapy.

The key player in this process is a small molecule called propionyl‑CoA, which is produced when isoleucine and valine are broken down. Normally, cells use a protein called SREBP2 as a thermostat for cholesterol: when cholesterol is low, SREBP2 turns on cholesterol-making genes; when cholesterol is high, it switches them off. The study found that propionyl‑CoA disrupts this safety mechanism by chemically modifying (propionylating) SREBP2, locking it in the “on” position so the cell keeps making cholesterol even when it should stop.

With cholesterol production running unchecked, prostate cancer cells gain the raw material they need to synthesize androgens locally. This reactivates the androgen receptor pathway and blunts the effect of hormone therapies such as enzalutamide that aim to shut that pathway down. Importantly, the researchers observed that propionyl‑CoA levels rise when cancer cells are deprived of androgens, suggesting tumors deliberately turn on this metabolic route as a survival strategy under treatment pressure.

In mouse models, the team tested whether cutting off the fuel for this pathway could slow the disease. Restricting dietary isoleucine and valine reduced tumor growth and decreased metastases to the lungs, while artificially raising propionyl‑CoA had the opposite effect, promoting growth and spread. These findings raise the possibility that carefully controlled dietary strategies, lowering intake of these amino acids, which are abundant in meat, fish, and dairy, might one day be combined with existing hormone therapies to improve outcomes.

The study also points to drug-based approaches. Enzymes that convert isoleucine and valine into propionyl‑CoA could be targeted with inhibitors, potentially preventing tumors from activating this resistance pathway in the first place. Another implication involves statins, widely used cholesterol-lowering drugs that have shown mixed results in prostate cancer. Because this newly described pathway directly fuels cholesterol biosynthesis, measuring its activity might help identify which patients are most likely to benefit from statins alongside standard care.

While the results are compelling, important questions remain before they reach the clinic. It is not yet known whether dietary restriction of isoleucine and valine can be done safely in cancer patients, especially those at risk of muscle loss or cachexia. Conditions like obesity and diabetes are linked to altered amino acid levels, but whether they raise propionyl‑CoA inside tumors is still unclear. The researchers emphasize that the long-term goal is to determine whether drugs or precisely managed dietary interventions can make current treatments work better, turning a metabolic workaround used by tumors into a vulnerability we can exploit.

For patients and clinicians, the message is cautious optimism. This work does not recommend immediate dietary changes, but it does highlight a concrete, testable link between nutrients, cholesterol, and hormone signaling in prostate cancer. If future trials confirm that lowering isoleucine and valine intake or blocking propionyl‑CoA production is safe and effective, it could open a new front in the fight against treatment-resistant disease, one that complements existing therapies rather than replacing them.

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