An RNA Aptamer Binding With Tumor Endothelial Marker I

Abstract

The commonest strategy of dealing with cancer depends on availability of tools to detect them at early stage and selectively eliminate the cancer cells. Certain molecules differentially expressed on cancer cell surface offer a basis for developing diagnostic as well as therapeutic tools. Tumor endothelial marker I (TEM I) is one such marker expressed on surface of solid tumors. Beginning with a random sequence library we have selected for RNA molecules specifically binding with a TEMI peptide following a SELEX protocol. Surface plasmon resonance assays showed Kd for some of the TEMI‐binding aptamers to be in nanomolar range. We have also put this molecule in context with cytotoxin‐coding sequence along with an internal ribosome entry site borrowed from ras I. We hope to use this chimeric construct for targeted delivery of cytotoxin to tumor cells. This would result in targeted killing of the tumor cells and can also be used as supplement to surgical removal to ensure any transformed cells escaping surgical removal. We are also developing chimeric molecules with fluorophores for detection of TEM I on cell surface.