Pep42, a cyclic peptide ligand of GPR78, internalizes selectively into highly metastatic human melanoma cells through a receptor-mediated process[1].
References
[1] Youngsoo Kim, et al. Targeting heat shock proteins on cancer cells: selection, characterization, and cell-penetrating properties of a peptidic GRP78 ligand. Biochemistry. 2006 Aug 8;45(31):9434-44. DOI:10.1021/bi060264j
