Cancer-associated fibroblasts promote prostate tumor growth and progression through upregulation of cholesterol and steroid biosynthesis https://biosignaling.biomedcentral.com/articles/10.1186/s12964-019-0505-5

From the study above: dual targeting of cholesterol and steroid biosynthesis with simvastatin, a commonly prescribed cholesterol synthesis inhibitor, and an inhibitor against AKR1C3 had the strongest growth inhibitory effect.

Searching for available AKR1C3 inhibitors. Here are some:

Compounds of interest include indomethacin 19 which was selective for AKR1C3; the N-phenylanthranilates (e.g. meclofenamic acid 23) were pan-AKR1C inhibitors; and aryl pro-pionic acids (e.g. naproxen 25) displayed equal AKR1C2 and AKR1C3 selectivity and potency. This led to the repurposing of these NSAIDs for AKR1C3 inhibition while eliminating inhibition of the COX-isoforms (PGH synthase I and II). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5724044/

Natural products such as baccharin analogs 29 (from the Brazilian propolis) have also be claimed as AKR1C3 inhibitors https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5724044/

Berberine https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4955188/

Based on the above, combinations of:

1. Simvastatin + Indomethacin and/or Naproxen may be a solution against prostate cancer

2. a natural alternative to the above (not necessarily as effective) is Citrus Bergamot + Brazilian propolis and/or Berberine