PDEF induce luminal differentiation in metastatic prostate cancer cells
Authors: Wang Fengtian , Koul Sweaty , Shanmugam Prakash Srinivasan Timiri , Dong Qin , Koul Hari K. 
Published: November 2023

Background

Secretory luminal cells, basal cells and rare neuroendocrine cells are the major component of prostate glandular structure. Basal cells are suggested to be more stem cell like and may generate neuronal phenotype cells. Cell differentiation initiated by key transcription factors in association with enhancer and super‐enhancer elements drives cell identity. Loss of epithelial phenotype is one of the hallmarks of tumor metastasis. Our previous studies have shown that Sam Pointed Domain Ets Transcription Factor a.k.a. Prostate Derived Ets Factor (SPDEF/PDEF), inhibits cell migration, invasion and clonogenic activity in prostate cancer (PCa) cells and there is a graded loss of PDEF protein expression with increasing disease grade in PCa patients. PDEF has been reported to be one of the cell identity transcription factors in LNCaP cells. We proposed that PDEF functions as a putative tumor metastasis suppressor which restores luminal phenotype and drug sensitivity in aggressive/metastatic prostate cancer cells. Others have shown an increase in Twist1, a basic helix‐turn‐helix transcription factor, was positively correlated with disease progression. present study was designed to investigate the role of PDEF and its interplay between PDEF and Twist1 in PCa.

Methods

PC3 cells were stably transfected with PDEF/control PABABE vectors. Gene expression changes were monitored by Affymetrix microarray. Gene expression patterns were analyzed by Gene Set Enrichment Analysis. qRT‐PCR was performed to confirm gene expression and Immunohistochemistry, Immunofluorescence and Immunoblot analysis were performed to visualize protein expression. Chip‐seq data (SRP002475) was aligned with Bowtie. Peaks were identified by MACS and visualized using Integrative Genome Browser. PDEF/Twist1 expression data was extracted from GSE16560. GraphPad was used to generate KM survival analysis of PCa patients.

Results

Our results show that PDEF expression is limited to luminal cells of the prostatic glands. we observed that expression of Twist1 was down regulated in PC3 cells following PDEF re‐expression. Analysis of global gene expression data from our microarray studies revealed that PDEF re‐expression was associated with negative enrichment of cell migration/metastasis genes while positively enriched of AR signaling and luminal differentiation genes. qRT‐PCR further showed transcriptional inhibition of genes involved in neuroendocrine feature and cell stemness. Chip‐seq analysis followed with Chip‐qPCR revealed a putative PDEF binding site within KRT8/18 promoter region. While loss of PDEF in LNCaP cells results in increased tumor metastasis and migration. These data suggest that PDEF inhibits core metastasis related genes through promoting a program of luminal differentiation. We also observed re‐express PDEF in PC3 cells could sensitize it towards androgen deprivation therapies.

Conclusions

PDEF inhibits cell migration and tumor metastasis in part by restoring androgen receptor signaling and directly regulates cytokeratin 8/18. Additional studies are underway to gain further insights into the role of PDEF in PCa progression and metastasis.

Support or Funding Information

Carrol W. Feist Endowed Chair funds (Koul H), FWCC support and Chair commitment funds (Koul H)