Cancer selectivity of tetrabranched neurotensin peptides is generated by simultaneous binding to sulfated glycosaminoglycans and protein receptors

In previous papers we demonstrated that tetrabranched peptides containing the sequence of human neurotensin, NT4, are much more selective than native monomeric analogues for binding to different human cancer cells and tissues. We show here that the much higher binding of NT4 peptides, with respect to native neurotensin, to either cancer cell lines or human cancer surgical samples is generated by a switch in selectivity toward additional membrane receptors, which are specifically expressed by different human cancers. We demonstrate that the branched structure provides NT4 with ability to bind heparin and receptors belonging to the low density lipoprotein receptor (LDLR) family, known to be involved in cancer biology. Systematic modification of neurotensin sequence in NT4 peptides led to identification of a multimeric positively charged motif, which mediates interaction with both heparin and endocytic receptors. Our findings provide the molecular basis for construction of cancer theranostics with high cancer selectivity.