Development of PowerMag System II for Isolation of Circulating Tumor Cells with Improved Purity

Area of Science:

• Biotechnology
• Molecular Biology
• Cancer Research

Background:

• The PowerMag system isolates circulating tumor cells (CTCs) by depleting CD45+ leukocytes.
• A significant population of EpCAM-CD45- cells contaminates CTC isolates, reducing purity and hindering molecular characterization.
• Characterizing these EpCAM-CD45- cells and enhancing the isolation system are crucial for improving CTC purity.

Purpose of the Study:

• To characterize the cellular properties of EpCAM-CD45- cells.
• To upgrade the PowerMag system for improved CTC purity by removing EpCAM-CD45- cells.
• To evaluate the performance of the upgraded system using clinical blood samples.

Main Methods:

• Real-time RT-PCR, Liu's stain, and Annexin V (AnxV) binding assays were used to define EpCAM-CD45- cell properties.
• An upgraded system incorporating AnxV beads was developed to remove EpCAM-CD45- cells.
• The efficacy of the upgraded system (PM II) was assessed with clinical blood samples.

Main Results:

• EpCAM-CD45- cells were identified as apoptotic cells with characteristic morphology and AnxV binding.
• In-house developed AnxV beads effectively captured and removed these apoptotic cells.
• The PM II system, integrating AnxV beads, achieved higher CTC purity by removing apoptotic background cells.
• PM II enabled direct cancer gene mutation profiling via next-generation sequencing without prior cell picking.

Conclusions:

• The PM II system significantly enhances CTC isolation purity through effective removal of apoptotic cells.
• PM II shows strong potential for clinical applications in cancer diagnosis and monitoring.
• The improved purity facilitates direct molecular profiling of CTCs, advancing cancer research and diagnostics.