Drug Combination Shows Promise Against Treatment-Resistant Prostate Cancer

A University of Michigan study suggests that combining two types of drugs could offer a new approach to treating advanced, treatment-resistant prostate cancer. The research focused on tumors that have changed their identity through a process called transdifferentiation. These tumors can become more aggressive and may no longer respond well to standard treatments that target male hormones.

The researchers studied BET inhibitors, drugs that block proteins involved in controlling gene activity. Earlier work showed that BET inhibitors could interfere with the pathways that help prostate cancer cells adopt new identities. However, the drugs mainly slowed the cancer’s growth and did not completely kill the cells or prevent the disease from returning.

The team then combined BET inhibitors with DNMT inhibitors. DNMT inhibitors affect chemical changes that can switch genes off. By reversing some of these changes, the drugs may reactivate genes linked to the normal identity of prostate cells and make the cancer cells less adaptable.

In laboratory experiments, the combination slowed the growth of prostate cancer cells more effectively than either drug alone. The researchers also tested the treatment in mice implanted with human prostate tumors. The tumors in mice receiving both drugs grew significantly more slowly and remained smaller than those in untreated mice or mice given only one of the drugs.

The combination also reversed many of the gene-activity changes associated with transdifferentiated prostate cancer. This suggests that the treatment may do more than slow cell division: it may partially push the cancer cells away from the aggressive state that helps them survive treatment.

Another encouraging finding was that the combination reduced tumor growth at relatively low doses and was well tolerated by the mice. Still, results in animals do not necessarily predict what will happen in people. Human trials are needed to determine the safest dose, possible side effects, and whether the treatment can produce meaningful benefits for patients.

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