Bacteriophage biopanning in human tumour biopsies to identify cancer-specific targeting ligands.

Cancer Research UK Institute for Cancer Studies, University of Birmingham, and Department of Surgery, Selly Oak Hospital, UK.
Journal of Drug Targeting (Impact Factor: 2.77). 06/2007; 15(4):311-9. DOI: 10.1080/10611860701195510
Source: PubMed

ABSTRACT Intravenous targeting of anticancer agents should improve both efficacy and therapeutic index. However, rational design of targeting constructs requires detailed definition of receptor targets and must take account of polarised tissue architecture that may restrict access to chosen receptors from the bloodstream. Bacteriophage biopanning provides a solution to this problem, identifying targeting sequences by functional selection rather than design, although reiterative panning in polarized human tumours has not previously been attempted. Here, we report an ex vivo, intra-arterial method for biopanning in freshly-resected human tumours, enabling reiterative selection of oligopeptide sequences capable of intravascular targeting to human colorectal tumours. Significant consensus was observed after two rounds of panning in tumours from different patients, and lead sequences demonstrated tumour targeting in samples from unrelated patients. This novel approach may be applicable to a wide range of settings, thus enabling iteration of consensus targeting sequences for tumour imaging and selective delivery of anticancer agents.

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    ABSTRACT: AIM: To identify linear peptide homing to non-small cell lung cancer (NSCLC) tumor cells using ex vivo phage display method. MATERIALS AND METHODS: Twenty-six clinical patient samples were used to identify linear homing peptide, which was exposed to NSCLC cell cultures and control cell lines to determine cell binding affinity and cell localization. Also, ex vivo biodistribution was analyzed using tumor-bearing mice. RESULTS: The panning yielded peptide enrichment with a core motif (A)/(S)RXPXXX. Based on this, an amino acid sequence, ARRPKLD, was selected for characterization and named Thx-peptide. The in vitro binding properties of Thx-peptide demonstrated selectivity toward NSCLC. Internalization assays showed that Thx-Alexa and fluorescein conjugates were located in a subset of perinuclearly located lysosomes of tumor cells. Thx-peptide appeared with fluorescein-labeled peptide and peptide-DTPA-chelator complex in adenocarcinoma xenografts in mice. CONCLUSION: Thx shows promise for targeted imaging and drug delivery.
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