Integrated Analysis of Multiple Biomarkers from Circulating Tumor Cells Enabled by Exclusion-Based Analyte Isolation

Area of Science:

• Oncology
• Biomarker Discovery
• Molecular Diagnostics

Background:

• Clinical need for predictive and pharmacodynamic biomarkers in targeted cancer therapy.
• Current limitations in evaluating pathway activity in patients.

Purpose of the Study:

• Develop and validate the VERSA platform for comprehensive analysis of the androgen receptor (AR) signaling pathway in circulating tumor cells (CTCs).
• Integrate protein, mRNA, and DNA readouts from CTCs for a holistic view of pathway activity.

Main Methods:

• Development of a microscale, exclusion-based platform (VERSA) for CTC capture, enumeration, and molecular analysis.
• Validation in cell lines and a cohort of castrate-resistant prostate cancer (CRPC) patients.
• Analysis of AR protein expression, localization, gene expression, and genetic alterations (copy number, mutations) in CTCs.

Main Results:

• VERSA successfully analyzed AR signaling in cell lines and CRPC patient CTCs.
• Radiographic progression was predicted by AR splice variants and pathway activity.
• Phenotypic heterogeneity identified through AR protein expression and nuclear localization.
• Longitudinal CTC analysis revealed acquisition of AR variants during treatment.

Conclusions:

• Complex resistance mechanisms to AR-targeted therapies in CRPC can be quantified in CTCs.
• Interrogation of the AR signaling pathway in CTCs provides pharmacodynamic biomarkers for targeted therapies.
• The VERSA platform enables comprehensive analysis of AR pathway activity and resistance mechanisms.