RSPO2 gene identified as key driver in metastatic prostate cancer

A new research paper was published in Volume 16 of Oncotarget on July 25, 2025, titled "Dissecting the functional differences and clinical features of R-spondin family members in metastatic prostate cancer."

In this study, researchers led by first author Aiden Deacon and corresponding author Justin Hwang from the University of Minnesota-Twin Cities investigated a group of genes known as the R-spondin family (RSPO1/2/3/4) in advanced prostate cancer (PC). The RSPO gene family regulates Wnt signaling, a pathway involved in cancer progression.

Prostate cancer is the most common cancer among men in the United States and becomes especially dangerous when it spreads beyond the prostate. Most patients are treated with hormone therapies that target the androgen receptor; however, many tumors eventually become resistant.

The research team analyzed thousands of tumor samples and found that RSPO2 alterations were more common than changes in other R-spondin genes or even some well-known cancer-related genes like CTNNB1 and APC. RSPO2 amplification occurred in over 20% of metastatic prostate cancer. Patients with these alterations showed signs of more aggressive disease, including higher mutation rates and greater tumor complexity.

Using laboratory models, the team discovered that RSPO2 increases cancer cell growth and triggers a biological process called epithelial-mesenchymal transition (EMT). EMT is known to promote tumor spread and resistance to standard treatments. Unlike other genes in the same pathway, RSPO2 also appeared to reduce the activity of androgen receptor genes, suggesting it drives a type of prostate cancer that no longer relies on hormones for growth.

"In cell lines, RSPO2 overexpression caused up-regulation of EMT pathways, including EMT-regulatory transcription factors ZEB1, ZEB2, and TWIST1."

Importantly, RSPO2 showed structural differences from other R-spondin proteins, which may allow researchers to design drugs that specifically block its activity. Current therapies targeting the Wnt pathway are limited, and there are no approved drugs that inhibit RSPO2. However, this study highlights RSPO2 as a promising therapeutic target, especially for patients who do not respond to existing hormone-based treatments.

This research adds critical knowledge about how aggressive prostate cancers develop and persist despite therapy. The identification of RSPO2 as a key driver of disease progression opens new possibilities for treatment strategies aimed at improving outcomes for patients with advanced prostate cancer.