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Ligand-Directed Photo-Proximity Labeling Technology For Profiling And Detecting Cancer Biomarker Interactions In Live Cells

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Lead Inventor: Raymond Moellering
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SUMMARY

Light-activated chemical probes to label and identify proteins near cancer biomarkers on live cells and tissues, enabling detailed study of protein interactions and signaling pathways relevant to cancer diagnosis and progression

 

The Unmet Need: Innovative tools that enable robust, selective, and temporally controlled profiling of protein interactions and biomarkers in live, unmodified cells and tissues

  • The study of protein-protein interactions (PPIs) and the identification of cell surface biomarkers are critical areas in molecular biology and biomedical research, particularly for understanding complex signaling pathways involved in diseases such as cancer. Traditional methods for mapping PPIs and profiling biomarkers, such as immunoprecipitation, affinity purification, and proximity labeling, have enabled significant advances in elucidating cellular networks. However, these approaches often require genetic modification of target cells, rely on overexpression of tagged proteins, or are limited to fixed or lysed samples, which can disrupt native protein interactions and fail to capture dynamic processes in live cells and tissues. The ability to study these interactions in their native context, with high spatial and temporal resolution, is essential for unraveling the molecular mechanisms underlying disease progression and for identifying clinically relevant biomarkers.

  • Current approaches to proximity labeling and biomarker detection face several significant limitations. Many techniques depend on genetically encoded tags, such as SNAP-tag or BioID, which restrict their use to cell lines amenable to genetic manipulation and are not easily applicable to primary tissues or patient-derived samples. Additionally, stoichiometric labeling methods often lack the sensitivity required to detect low-abundance proteins and may generate high background signals due to non-specific labeling. Temporal control over labeling reactions is frequently inadequate, making it challenging to capture transient or context-dependent interactions. Furthermore, existing methods may not provide sufficient specificity for targeting particular protein microenvironments, such as integrin-rich regions implicated in cancer metastasis

The Proposed Solution: Ligand-directed photo-proximity labeling system comprising a targeting ligand linked to a photosensitizer enabling detailed profiling of protein interactions and biomarker microenvironments in live cells and tissues

  • The faculty inventor developed a ligand-directed photo-proximity labeling platform designed for the sensitive and robust detection of protein-protein interactions, particularly those involving integrin receptors, in live cells and tissues. The core of the solution is a specially engineered probe composed of an RGD peptide ligand, which selectively targets integrin receptors, covalently linked to a lumichrome-based photosensitizer. Upon exposure to specific wavelengths of light (365 nm or 440 nm), the photosensitizer generates reactive radicals that covalently label proteins in close proximity to the targeted integrins. The probe is synthesized through a multi-step chemical process, culminating in the coupling of the peptide to the photosensitizer and purification by HPLC. This approach enables precise, temporally controlled labeling of protein microenvironments, which can then be analyzed by mass spectrometry to profile protein networks, signaling pathways, and post-translational modifications in both cultured cells and tissue samples, including tumor xenografts.

  • What differentiates this technology is its photocatalytic mechanism, which allows for highly sensitive detection of low-abundance proteins without the need for genetically engineered tags or overexpression systems. Unlike traditional stoichiometric labeling or SNAP-tag-based methods, this platform leverages high-affinity ligand targeting and light activation to achieve rapid, selective, and low-background labeling in native biological contexts. Its compatibility with live cells and primary tissues, as well as its demonstrated effectiveness across various cancer cell lines and in vivo tumor models, enables detailed mapping of integrin-associated protein networks and dynamic signaling events. Furthermore, the technology's ability to identify clinically relevant biomarkers and prognostic indicators in aggressive cancers underscores its potential for both basic research and translational applications in oncology.

ADVANTAGES

ADVANTAGES

  • Enables sensitive and robust detection of low-abundance cancer biomarker proteins in live cells and tissues

  • Provides fine temporal control of protein labeling through light-activated photo-proximity labeling

  • Does not require genetic modification of target cells, allowing application to native cells and primary tissue samples

  • Facilitates detailed profiling of protein-protein interactions and integrin-related signaling pathways in cancer

  • Supports identification of dynamic interactions and post-translational modifications in the native cellular microenvironment

APPLICATIONS

  • Cancer biomarker detection in tissues

  • Profiling tumor microenvironments

  • Identifying prognostic cancer markers

  • Drug target validation in oncology

  • Mapping integrin signaling pathways

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