In a groundbreaking study that could reshape the understanding and treatment of aggressive prostate cancer, researchers at the University of Michigan Rogel Cancer Center have identified a pivotal gene implicated in the transition of prostate tumor cells into lethal, treatment-resistant forms. This discovery centers around the gene PROX1, which has been shown to drive a cellular transformation process known as lineage plasticity, ultimately contributing to the tumor cells’ ability to evade androgen receptor-targeted therapies. This revelation not only sheds light on the elusive mechanisms underlying prostate cancer progression but also proposes an innovative therapeutic strategy using a class of FDA-approved drugs.
Prostate cancer, long targeted primarily through therapies aimed at the androgen receptor (AR), often evolves into forms that no longer depend on this signaling pathway, thereby rendering these treatments ineffective. The process of lineage plasticity—where cancer cells alter their identity and become resistant to hormonal therapies—poses a significant clinical challenge. This new research, led by senior author Dr. Joshi J. Alumkal and spearheaded by Zhi Duan, Ph.D., elucidates a molecular driver behind this change, offering hope for patients grappling with aggressive prostate tumors that have outmaneuvered existing treatment modalities.
Their investigation unveiled PROX1 as an early and critical marker in the transformation from androgen receptor-dependent prostate cancer to its more aggressive, androgen receptor-independent subtypes, including double-negative prostate cancer and neuroendocrine prostate cancer. Notably, PROX1 expression was found to increase sharply in tumor cells that lost AR activity, correlating with more aggressive disease phenotypes. By analyzing hundreds of patient tumor biopsies along the lineage plasticity continuum, the researchers established PROX1 not only as a biomarker but as a possible causal agent facilitating the malignant reprogramming of prostate cancer cells.
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At a mechanistic level, PROX1 acts as a transcription factor, a protein that binds DNA and controls the expression of other genes, effectively orchestrating the identity and behavior of cancer cells. The study demonstrated an inverse relationship between PROX1 and the androgen receptor across patient tumor datasets, suggesting that PROX1 may actively repress AR expression and function. Experimentally, forcing PROX1 expression in prostate cancer cells resulted in downregulation of AR, reinforcing the idea that PROX1 suppresses AR-driven pathways, fostering cellular plasticity and progression towards treatment-resistant states.
Genetic ablation experiments, which selectively knocked out PROX1 from double-negative and neuroendocrine prostate cancer cells, resulted in significant growth arrest and increased cell death. This evidence firmly supports the notion that PROX1 is not merely a passenger in lineage plasticity but a driver essential for the survival and proliferation of aggressive prostate cancer subtypes. However, the challenge lies in targeting PROX1 pharmacologically, as transcription factors historically have proven difficult to inhibit directly with drugs.
Pivoting around this obstacle, the researchers uncovered a promising indirect strategy by investigating proteins that interact with PROX1. Among these cofactors, histone deacetylases (HDACs) stood out as significant partners. HDACs are enzymes that modify chromatin structure and regulate gene expression and have been successfully targeted in other cancer types with approved inhibitors. Hypothesizing a cooperative relationship, the team tested whether inhibiting HDAC activity could disrupt PROX1 function.
Their results were striking. Treatment of PROX1-expressing prostate cancer cells with HDAC inhibitors led to a notable reduction in PROX1 protein levels, mirroring the effects observed with genetic deletion. As PROX1 diminished, cell viability decreased dramatically, indicating that HDAC inhibitors can thwart the survival mechanisms of these aggressive cancer cells by destabilizing PROX1. Given that HDAC inhibitors are already clinically approved for several cancers, these findings open immediate avenues for repurposing these drugs to combat prostate cancer subtypes prone to lineage plasticity.
This discovery carries profound implications for the future management of prostate cancer. By identifying PROX1 as an early driver of lineage plasticity and establishing a link between PROX1 and HDACs, the study provides a molecular rationale for clinical trials testing HDAC inhibitors in patients with aggressive, androgen receptor-independent prostate cancer. Such trials could herald a new therapeutic frontier for individuals currently facing limited options and poor prognoses.
The research conducted at the University of Michigan Rogel Cancer Center involved a multidisciplinary team of experts spanning molecular biology, oncology, and translational medicine. Utilizing patient-derived tumor biopsies, sophisticated genetic manipulation techniques, and advanced cellular assays, the investigators meticulously mapped PROX1’s role in prostate cancer evolution. Their integrative approach underscores the importance of combining genetic insights with pharmacological innovations to tackle complex, treatment-resistant malignancies.
While the study highlights a promising therapeutic target, further research is necessary to delineate the precise molecular pathways by which PROX1 and HDACs interact and regulate prostate cancer cell fate. It also raises intriguing possibilities about whether similar lineage plasticity mechanisms operate in other cancers, potentially broadening the impact of these findings. Moreover, identifying biomarkers that predict response to HDAC inhibition in prostate cancer patients will be critical for translating these discoveries into clinical benefit.
In addition to advancing fundamental knowledge, this work emphasizes the power of “guilt by association” in drug targeting—leveraging the interactions of untargetable proteins like PROX1 with druggable partners such as HDACs. This conceptual framework could transform how researchers approach other intractable oncogenic drivers in cancer biology, accelerating the development of effective therapies where none currently exist.
As the field anticipates clinical trials informed by this study, patients and clinicians alike have renewed optimism that understanding lineage plasticity at the genetic and epigenetic levels will unlock new keys to controlling and, ultimately, overcoming aggressive prostate cancer. The convergence of molecular biology, genomics, and pharmacology displayed in this research exemplifies the promise of precision medicine in oncology.
This seminal study, entitled “PROX1 is an Early Driver of Lineage Plasticity in Prostate Cancer,” appeared in the Journal of Clinical Investigation and represents a significant stride toward identifying novel intervention points in the fight against one of the most challenging forms of cancer progression. The collaboration between genetic analysis and therapeutic innovation showcased here illustrates how tackling the molecular roots of cancer can translate into tangible clinical advances.
In summary, the identification of PROX1 as a central regulator of prostate cancer lineage plasticity and its functional suppression via HDAC inhibitors heralds an exciting development in cancer research. By potentially repurposing existing drugs to inhibit this newly characterized pathway, the study charts a viable route to counteract treatment-resistant prostate cancer and improve patient outcomes in an area of urgent unmet medical need.
Subject of Research: Cells
Article Title: PROX1 is an early driver of lineage plasticity in prostate cancer
News Publication Date: 2-Jun-2025
References: “PROX1 is an Early Driver of Lineage Plasticity in Prostate Cancer,” Journal of Clinical Investigation
Image Credits: Image courtesy of Michael C. Haffner, M.D., Ph.D., Fred Hutchinson Cancer Center
Keywords: Cancer, Prostate cancer
Tags: androgen receptor-targeted therapiesclinical challenges in prostate cancer treatmentearly indicators of lethal prostate tumorsFDA-approved drugs for cancer treatmentinnovative therapeutic strategies for prostate cancerlineage plasticity in cancer cellsmolecular drivers of cancer progressionprostate cancer aggressivenessPROX1 gene and prostate cancertreatment-resistant prostate cancerunderstanding prostate tumor evolutionUniversity of Michigan Rogel Cancer Center research
