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Updated: Jan 5, 2026
Phosphopeptide Enrichment Coupled with Label-free Quantitative Mass Spectrometry to Investigate the Phosphoproteome in Prostate Cancer
Published on: August 2, 2018
Evaluation of Small Molecule Drug Uptake in Patient-Derived Prostate Cancer Explants by Mass Spectrometry
Shadrack M Mutuku1,2, Paul J Trim3, Bala K Prabhala3,4
1Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia.
Abstract:
Patient-derived explant (PDE) culture of solid tumors is increasingly being applied to preclinical evaluation of novel therapeutics and for biomarker discovery. In this technique, treatments are added to culture medium and penetrate the tissue via a gelatin sponge scaffold. However, the penetration profile and final concentrations of small molecule drugs achieved have not been determined to date. Here, we determined the extent of absorption of the clinical androgen receptor antagonist, enzalutamide, into prostate PDEs, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and matrix-assisted laser/desorption ionisation (MALDI) mass spectrometry imaging (MSI). In a cohort of 11 PDE tissues from eight individual patients, LC-MS/MS quantification of PDE homogenates confirmed enzalutamide (10 µM) uptake by all PDEs, which reached maximal average tissue concentration of 0.24-0.50 ng/µg protein after 48 h culture. Time dependent uptake of enzalutamide (50 µM) in PDEs was visualized using MALDI MSI over 24-48 h, with complete penetration throughout tissues evident by 6 h of culture. Drug signal intensity was not homogeneous throughout the tissues but had areas of markedly high signal that corresponded to drug target (androgen receptor)-rich epithelial regions of tissue. In conclusion, application of MS-based drug quantification and visualization in PDEs, and potentially other 3-dimensional model systems, can provide a more robust basis for experimental study design and interpretation of pharmacodynamic data.
Insights
Patient-derived explant (PDE) cultures effectively absorb drugs like enzalutamide. Mass spectrometry imaging visualized complete drug penetration within 6 hours, highlighting target-rich regions for improved preclinical therapeutic evaluation.
Area of Science:
- Oncology
- Pharmacology
- Biomedical Engineering
Background:
- Patient-derived explant (PDE) cultures are vital for preclinical drug testing and biomarker discovery in solid tumors.
- Current limitations include a lack of understanding regarding drug penetration and final concentrations within PDE models.
- This study addresses the critical need to characterize drug distribution in 3D tumor models.
Purpose of the Study:
- To determine the penetration profile and concentration of enzalutamide in prostate patient-derived explant (PDE) cultures.
- To visualize drug distribution within tumor tissues using advanced mass spectrometry techniques.
- To establish a foundation for more robust experimental design and interpretation of pharmacodynamic data in PDE models.
Main Methods:
- Utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantitative drug analysis in PDE homogenates.
- Employed matrix-assisted laser/desorption ionisation (MALDI) mass spectrometry imaging (MSI) to visualize enzalutamide distribution over time.
- Analyzed 11 PDE tissues from eight individual patients to assess drug uptake and penetration.
Main Results:
- Confirmed enzalutamide uptake in all analyzed PDEs, with maximal average concentrations ranging from 0.24-0.50 ng/µg protein after 48 hours.
- MALDI MSI demonstrated complete enzalutamide penetration throughout the tissues within 6 hours of culture.
- Drug signal intensity was heterogeneous, with higher concentrations observed in androgen receptor-rich epithelial regions.
Conclusions:
- Mass spectrometry-based methods provide robust quantification and visualization of drug distribution in PDE models.
- This approach enhances the reliability of experimental study design and the interpretation of pharmacodynamic data.
- The findings support the utility of PDEs and other 3D models for preclinical drug development.
