As reported on Science Daily, researchers at the University of Michigan have identified a potential new therapeutic approach for aggressive prostate cancers that become resistant to standard hormone-targeting treatments. Preclinical findings suggest that combining two different classes of drugs may slow tumor growth by reversing key biological changes that allow cancer cells to evade therapy.
Prostate cancer remains one of the most common malignancies among men, and while many patients respond well to initial treatment, advanced disease can eventually progress despite therapy. A major challenge arises when tumors develop resistance to androgen receptor inhibitors, a cornerstone treatment for metastatic prostate cancer.
Scientists have increasingly recognized that some resistant tumors escape treatment by undergoing a process known as transdifferentiation. During this transition, prostate cancer cells abandon many of their normal gland-like characteristics and adopt alternative cellular states that are less dependent on androgen signaling. These identity shifts are associated with more aggressive disease and fewer effective treatment options.
In a study published in JCI Insight, investigators examined the molecular events that drive this transformation. The team focused on tumors that had lost the tumor-suppressor genes TP53 and RB1, genetic alterations previously linked to treatment resistance and cellular reprogramming.
Their analyses revealed two major biological changes occurring during transdifferentiation: the suppression of genes associated with normal prostate gland function and the activation of genetic programs that promote stem cell-like traits. Researchers concluded that both processes contribute to the development of therapy-resistant disease.
To target these mechanisms, the investigators evaluated a combination of BET bromodomain inhibitors and DNA methyltransferase (DNMT) inhibitors. BET inhibitors are designed to disrupt molecular pathways that help cancer cells adopt alternative identities, while DNMT inhibitors can reactivate genes that have been silenced. Notably, several DNMT inhibitors are already approved for clinical use in certain blood cancers.
Laboratory experiments demonstrated that pairing the two drug types produced stronger anti-cancer effects than either treatment alone. The combination reduced the growth of prostate cancer cell lines more effectively and generated similar benefits in mouse models implanted with prostate tumors.
Researchers also observed that the dual-drug regimen reversed many of the gene-expression changes associated with transdifferentiation. Importantly, significant tumor-growth inhibition was seen even at relatively low drug doses, and the treatment was well tolerated in animal studies.
The findings suggest that simultaneously blocking the pathways that drive cellular identity changes while restoring lost prostate-specific gene activity may represent a more effective strategy for combating resistant tumors than targeting either process independently.
Looking ahead, the research team plans to identify biomarkers that could help determine which patients are most likely to benefit from this treatment approach. They also hope to better understand whether intervention earlier in the disease process could prevent transdifferentiation from occurring altogether.
Future clinical trials will be needed to determine whether the combination of BET bromodomain and DNMT inhibitors can improve outcomes in patients with advanced prostate cancer. Investigators are also exploring whether similar strategies could be effective in other cancers, including lung and pancreatic tumors, that undergo comparable shifts in cellular identity.
