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K.S. Lam

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    MINI 14 - Pre-Clinical Therapy (ID 119)

    • Event: WCLC 2015
    • Type: Mini Oral
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 1
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      MINI14.06 - High-Affinity α3β1 Integrin Ligand LXY30 for the Screening, Imaging and Targeted Drug Delivery in Non-Small Cell Lung Cancer (NSCLC) (ID 1758)

      10:45 - 12:15  |  Author(s): K.S. Lam

      • Abstract
      • Presentation
      • Slides

      High-affinity peptidomimetic or small-molecule ligands against cancer cell surface receptors have attracted wide interest as cancer-targeting agents to enhance cancer diagnosis and treatment. We have previously identified and characterized several peptide ligands specific for different integrins, such as a3b1, a4b1 and avb3, on live tumor cells using our invented high throughput one-bead one-compound (OBOC) random combinatorial libraries and “on-bead” whole-cell binding assay. The objective of this study was to select the best integrin ligand for the screening, imaging and targeted drug delivery studies in NSCLC.

      High-affinity integrin ligands coated on the surface of TentaGel resin beads were screened for the binding to a panel of NSCLC cell lines, malignant pleural effusion and peripheral blood mononuclear cells (PBMCs) from lung cancer patients using the established whole-cell binding assay. The binding affinity was determined in selected NSCLC tumors by flow cytometry using the biotinylated integrin ligands and Streptavidin-Phycoerythrin (PE). For in vivo biodistribution, mice bearing subcutaneous and intracranial NSCLC xenograft tumors were injected with LXY30-biotin-streptavidin-Cy5.5 conjugate for 6 hrs before being subjected to in vivo and ex vivo optical imaging.

      Among the available integrin ligands, LXY30, a recently optimized cyclic peptide targeting α3β1integrin, bound to the majority of NSCLC cell lines tested within one hour of incubation. We further demonstrated that LXY30 bound to α3β1 integrin on the surface of lung cancer cells with high specificity by flow cytometry and entered into the cells via endocytosis by fluorescence microscopy imaging. Flow cytometry confirmed the high specificity binding of LXY30 to NSCLC cells. While sparing the PBMCs isolated from lung cancer patients, LXY30 strongly bound to tumor cells in the pleural effusion from several NSCLC patients and could capture the tumor cells spiked into PBMCs in 1: 5,000 dilution after a 2-hour incubation. Furthermore, several EGFR-mutant lung cancer cell lines have high level expression of α3β1 integrin on their surface. In nude mice bearing two representative, EGFR-mutant lung cancer H3255 (EGFR L858R) and H1975 (EGFR 858R/T790M) xenograft tumors, optical images have shown the preferential updates of LXY30-biotin-streptavidin-Cy5.5 conjugate in the subcutaneous and intracranial xenograft tumors.

      The rapid, sensitive and high specificity binding of LXY30 makes it an ideal candidate for screening and isolating NSCLC tumor cells in the pleural effusion and whole blood. LXY30 can be used as a cancer-targeting agent to guide in vivo delivery of imaging dye and cancer drugs to the simulated extracranial and metastatic brain tumors.

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