Prostate Cancer

Prostate cancer is currently the most clinically advanced area of Urolithin A oncology research.

It is the only cancer type with an active placebo-controlled phase II trial of direct Urolithin A supplementation, and the only one with published human prostate-cancer-specific immune data.

The evidence divides naturally by disease setting.

Hormone-sensitive disease, castration-resistant disease, and immune modulation each bring different findings.

All in vitro and animal findings remain preclinical.

Where human evidence exists, it is identified clearly below.

Hormone-sensitive prostate cancer

Androgen-receptor suppression

Urolithin A has been shown to downregulate androgen-receptor expression and transcriptional activity in androgen-receptor-positive prostate-cancer models.

In C4-2B cells, which model androgen-insensitive castration-resistant disease but still retain androgen-receptor relevance, Urolithin A inhibited proliferation and suppressed both androgen-receptor and phospho-AKT signalling.

Androgen-receptor-positive cells appeared more sensitive than androgen-receptor-negative cells.

That suggests at least part of the effect is androgen-receptor-linked.

A pomegranate-fruit-extract trial in men with recurrent prostate cancer also found reductions in 8-OHdG and androgen-receptor expression in prostate tissue.

Urolithin A glucuronide was detected more often in the active-treatment arm.

This is not a direct Urolithin A trial.

It is still relevant because it links prostate-tissue changes to urolithin metabolism in a randomised human setting.

p53, MDM2, and apoptosis

Urolithin A induces apoptosis in prostate-cancer cells through both p53-dependent and p53-independent routes.

In LNCaP and 22Rv1 cells, it increased p53 and upregulated p21, PUMA, and NOXA.

It also inhibited the interaction between p53 and MDM2, reducing MDM2-mediated p53 degradation.

That helps sustain the apoptotic signal.

In AR-negative PC3 cells, Urolithin A still induced apoptosis through p14ARF and p21-related signalling.

That matters because it suggests activity does not disappear completely in less p53-dependent or androgen-receptor-independent settings.

Cell-cycle effects

Urolithin A also produces G1-phase arrest in prostate-cancer lines.

The clearest mechanism is p21 upregulation, confirmed at both mRNA and protein level, with promoter activation shown in luciferase work.

Caspase 3 and 7 activation has also been reported.

Oxidative DNA damage

Reduction of oxidative DNA damage is one of the most clinically relevant prostate-cancer themes.

This is also why 8-OHdG is the primary endpoint of the active URO-PRO study.

Both preclinical work and pomegranate-derived human data suggest Urolithin A may reduce oxidative damage inside prostate tumour tissue.

Because oxidative stress contributes to mutagenesis and treatment resistance, this is a meaningful mechanistic endpoint rather than a trivial biomarker.

Castration-resistant prostate cancer

Castration-resistant prostate cancer remains heavily shaped by androgen-receptor signalling, even after testosterone suppression.

That makes this setting especially relevant to Urolithin A.

The AR-V7 resistance problem

Urolithin A itself suppresses androgen-receptor signalling.

However, the more detailed AR-V7 work has been done with ASR-600, a Urolithin-A-related structural analogue rather than Urolithin A itself.

That analogue showed activity against both full-length androgen receptor and AR-V7, enhanced androgen-receptor ubiquitination, and suppressed growth of androgen-receptor-positive castration-resistant models.

This is not direct Urolithin A evidence.

It still matters because it shows the Urolithin-A scaffold is chemically relevant to one of the biggest resistance problems in advanced prostate cancer.

AR-dependent and AR-independent pathways

In addition to androgen-receptor suppression, Urolithin A also appears to inhibit AKT and mTOR signalling while increasing PTEN expression.

That is relevant because PTEN loss and PI3K/AKT pathway activation are common in advanced prostate cancer.

This gives Urolithin A a broader biological range than a purely androgen-receptor-focused compound.

Combination with androgen-deprivation therapy

Preclinical discussions suggest that Urolithin A and androgen-deprivation therapy may act on overlapping but not identical survival pathways.

That creates a plausible rationale for complementary use.

There is still no clinical combination dataset showing whether the effect is additive, synergistic, neutral, or problematic.

Human evidence — NK-cell activation

This is the strongest direct human prostate-cancer-specific evidence for Urolithin A.

A published ex vivo study incubated PBMCs from prostate-cancer patients and healthy controls with Urolithin A at physiologically relevant concentrations.

At 10 µM, Urolithin A increased NK-cell cytotoxic activity by an average of 23% in prostate-cancer patients.

The mechanism involved AhR antagonism.

The study also reported reductions in several pro-inflammatory cytokines from patient PBMCs, including fractalkine, IL-8, and MCP-3.

This is not an in vivo clinical outcome study.

It does show that Urolithin A can modulate immune function in cells derived from prostate-cancer patients at realistic concentrations.

Active clinical trial — URO-PRO

The URO-PRO study is the most important ongoing direct Urolithin A trial in any cancer type.

Key features include:

• phase II, randomised, placebo-controlled design

• men with biopsy-confirmed prostate cancer scheduled for radical prostatectomy

• Urolithin A 1000 mg/day versus placebo

• treatment for 3 to 6 weeks before surgery

• primary endpoint of change in 8-OHdG in tumour tissue

• secondary endpoints including cell-cycle gene expression and oxidative-damage markers in benign and adjacent tissue

This trial is important because it will provide the first placebo-controlled direct test of whether oral Urolithin A changes prostate tumour biology in humans.

Pomegranate-extract trials — useful context, but not direct proof

Several pomegranate-juice and pomegranate-extract studies in recurrent prostate cancer matter here because Urolithin A is one of the downstream metabolites likely to contribute to the observed effects.

These studies have reported PSA-doubling-time changes and tumour-biology signals in some groups.

They should not be treated as direct Urolithin A trials.

That distinction matters because pomegranate products contain many bioactives, and conversion to Urolithin A varies significantly between individuals.

The direct-supplement URO-PRO trial is important partly because it removes that metabotype-related uncertainty.

What remains unknown

Several important questions are still open.

• whether Urolithin A changes prostate tumour tissue enough to matter clinically — URO-PRO should help answer part of that

• what the best oncology-specific dose really is

• whether Urolithin A combines well with enzalutamide, abiraterone, docetaxel, or other standard advanced-disease treatments

• whether ex vivo NK-cell activation translates into meaningful in vivo anti-tumour benefit

• whether long-term outcomes such as recurrence, metastasis-free survival, or disease-free survival can be improved

Bottom line

Prostate cancer is currently the strongest clinical-development setting for Urolithin A.

That is because it combines:

• strong preclinical androgen-receptor and apoptosis biology

• oxidative-DNA-damage relevance

• direct human immune data

• and an active placebo-controlled phase II trial

Even here, the evidence is not yet practice-changing.

It is still investigational.

But it is more clinically advanced than the evidence base in any other cancer type studied so far.

References

Urolithin A induces prostate-cancer cell death in p53-dependent and p53-independent manners
https://pubmed.ncbi.nlm.nih.gov/31177307/

Urolithin A causes p21 up-regulation in prostate-cancer cells
https://walnuts.org/area-of-study/urolithin-a-causes-p21-up-regulation-in-prostate-cancer-cells/

A natural molecule, Urolithin A, downregulates androgen-receptor activation and suppresses growth of prostate cancer
https://pubmed.ncbi.nlm.nih.gov/30069922/

Urolithin A analog inhibits castration-resistant prostate cancer by targeting the androgen receptor and AR-V7
https://pmc.ncbi.nlm.nih.gov/articles/PMC10020188/

Urolithins as emerging natural compounds targeting castration-resistant prostate cancer
https://pubmed.ncbi.nlm.nih.gov/40253830/

Urolithin A increases the natural-killer activity of PBMCs in patients with prostate cancer
https://pmc.ncbi.nlm.nih.gov/articles/PMC11754188/

A phase II randomised placebo-controlled trial of pomegranate fruit extract in men with recurrent prostate cancer
https://onlinelibrary.wiley.com/doi/10.1002/pros.24076

Pomegranate juice metabolites, ellagic acid, and Urolithin A in androgen-independent prostate-cancer growth research
https://pmc.ncbi.nlm.nih.gov/articles/PMC3655614/

URO-PRO trial listing
https://www.cancer.gov/research/participate/clinical-trials-search/v?id=NCI-2023-03835