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Updated: May 13, 2026
Phosphopeptide Enrichment Coupled with Label-free Quantitative Mass Spectrometry to Investigate the Phosphoproteome in Prostate Cancer
Published on: August 2, 2018
Quantitative proteomic determination of diethylstilbestrol action on prostate cancer
Pierre Bigot1, Kevin Mouzat, Souhil Lebdai
1Department of Urology, Angers University Hospital, Angers 49933, France. pibigot@chu-angers.fr
Abstract:
Diethylstilbestrol (DES) has a direct cellular mechanism inhibition on prostate cancer. Its action is independent from the oestrogen receptors and is preserved after a first-line hormonal therapy. We aimed to identify proteins involved in the direct cellular inhibition effects of DES on prostate cancer. We used a clonogenic assay to establish the median lethal concentration of DES on 22RV1 cells. 22RV1 cells were exposed to standard and DES-enriched medium. After extraction, protein expression levels were obtained by two-dimensional differential in-gel electrophoresis (2D-DIGE) and isotope labelling tags for relative and absolute quantification (iTRAQ). Proteins of interest were analysed by quantitative RT-PCR and western blotting. The differentially regulated proteins (P<0.01) were interrogated against a global molecular network based on the ingenuity knowledge base. The 2D-DIGE analyses revealed DES-induced expression changes for 14 proteins (>1.3 fold; P<0.05). The iTRAQ analyses allowed the identification of 895 proteins. Among these proteins, 65 had a modified expression due to DES exposure (i.e., 23 overexpressed and 42 underexpressed). Most of these proteins were implicated in apoptosis and redox processes and had a predicted mitochondrial expression. Additionally, ingenuity pathway analysis placed the OAT and HSBP1 genes at the centre of a highly significant network. RT-PCR confirmed the overexpression of OAT (P=0.006) and HSPB1 (P=0.046).
Insights
Diethylstilbestrol (DES) directly inhibits prostate cancer cells, independent of estrogen receptors. This study identified 65 differentially expressed proteins, including OAT and HSPB1, involved in apoptosis and redox processes, offering new therapeutic targets.
Area of Science:
- Oncology
- Molecular Biology
- Proteomics
Background:
- Diethylstilbestrol (DES) exhibits direct cellular inhibition of prostate cancer.
- This effect is independent of estrogen receptors and effective after initial hormonal therapy.
Purpose of the Study:
- To identify proteins mediating the direct cellular inhibitory effects of DES on prostate cancer.
- To elucidate the molecular mechanisms underlying DES action in prostate cancer cells.
Main Methods:
- Utilized clonogenic assays to determine DES median lethal concentration on 22RV1 cells.
- Employed two-dimensional differential in-gel electrophoresis (2D-DIGE) and iTRAQ for protein expression analysis.
- Validated key protein changes using quantitative RT-PCR and western blotting.
Main Results:
- DES exposure altered the expression of 14 proteins (2D-DIGE) and 65 proteins (iTRAQ).
- Overexpressed and underexpressed proteins were primarily involved in apoptosis and redox processes, with predicted mitochondrial localization.
- Ingenuity pathway analysis highlighted OAT and HSPB1 as central to a significant molecular network.
Conclusions:
- DES exerts its prostate cancer inhibitory effects through specific protein expression changes.
- OAT and HSPB1 are key molecular players in DES-mediated prostate cancer cell inhibition.
- These findings suggest novel therapeutic strategies targeting DES-modulated pathways.
