Drugs used in the treatment of breast cancer could help improve care for men with prostate cancer, suggests
a study published in
The Journal of Clinical Investigation by a research team from Université Laval.
These drugs, which target estrogen receptors, could slow tumor progression in about 50% of men who have prostate cancer.
Half of prostate tumors have estrogen receptors. Their binding with estrogens produced by the testes promotes the progression of cancer cells. For this reason, researchers believe that antiestrogen drugs used to treat breast cancer might be considered for men with prostate cancer. — Nephron
"Estrogens are hormones we typically associate with women, but men also produce them, although in smaller quantities. They mainly come from the testes and, indirectly, from the adrenal glands that produce estrogen precursors," explains the study's lead,
Étienne Audet-Walsh, professor at the Faculty of Medicine, researcher at the CHU de Québec-Université Laval Research Center, and holder of the Canada Research Chair in Metabolic Vulnerabilities of Hormone-Sensitive Cancers.
In nearly 95% of men with prostate cancer, tumors proliferate in response to androgens, the so-called male sex hormones. This is why treatments that target these hormones are regularly used to treat this cancer. "These treatments work for a while, but over time their effectiveness fades. We wanted to know if estrogens and their receptors could be involved," explains Professor Audet-Walsh.
Initially, the researchers used biobanks of prostate tumors preserved by clinician-researchers in urology-oncology at Université Laval. "We studied 280 tumors and found that half of them exhibited estrogen receptors. By cross-referencing these results with patient medical records, we determined that the abundance of these receptors was linked to cancer recurrence risk, progression, metastasis formation, and patient survival. We observed the same relationship in studying tumors from several other biobanks," notes Professor Audet-Walsh.
Subsequent experiments conducted on cell cultures and animals all pointed in the same direction. When estrogens bind to estrogen receptors, they stimulate cellular mechanisms related to the metabolism and growth of prostate cancer cells. Conversely, antiestrogens—drugs that block estrogen receptors—reduce the proliferation and growth of prostate tumors.
"Our study could have significant clinical implications," suggests the researcher, "because it indicates that antiestrogen drugs currently used to treat breast cancer could also slow prostate cancer progression in men whose tumors have estrogen receptors. We now wish to conduct a clinical study to validate this hypothesis."
The number of new prostate cancer cases detected each year reaches about 7,000 in Quebec and 1.4 million worldwide. "If half of these men responded to antiestrogen treatments resulting in improved quality of life and better survival rates, it would be a significant advancement in treating prostate cancer patients," concludes Professor Audet-Walsh.
The first author of the article published in
The Journal of Clinical Investigation is student-researcher Camille Lafront. This study is part of her doctoral work at the Faculty of Medicine at Université Laval.