Identification of novel targeting peptides for human ovarian cancer cells using “one-bead one-compound” combinatorial libraries

Abstract

Using ''one-bead one-compound'' combinatorial chemistry technology, we generated random peptide libraries containing millions of 90 Mm TentaGel beads, each with its own unique amino acid sequence. A cyclic random 8-mer library was screened with CAOV-3 (a human ovarian adenocarcinoma cell line) and beads with a unique ligand that bind to the cell surface receptors were coated by one or more layers of cells. These positive beads were isolated, stripped, and microsequenced. Several peptide motifs were identified from these screenings, some of which were novel and unique, e.g., cDGX 4 GX 6 X 7 c. Structure-activity relationship studies of this peptide revealed that the L-aspartate residue at position 2, the two glycines at positions 3 and 5, and the two Dcysteines at the amino and COOH terminus are critical for activity. In addition, a hydrophobic residue was preferred at position X 4 , whereas amino acids at positions X 6 and X 7 were more variable. Binding of this peptide to a number of different cancer cell lines and normal cells was also determined and we observed that peptides with this motif bound preferentially to three other human ovarian cancer cell lines (ES-2, SKOV-3, and OVCAR-3) as well as a human glioblastoma cancer cell line (A172). Structural analysis of the peptides using high-resolution nuclear magnetic resonance spectroscopy revealed strong conformational similarity among all peptides with cX 1 GX 4 GX 6 X 7 c motif. Blocking study with a panel of anti-integrin antibodies strongly suggests A3 integrin present on these ovarian adenocarcinoma cells is the target receptor for this peptide. [Mol Cancer Ther 2005;4(5):806 -13]

Cyclic Arg-Gly-Asp Peptide-Labeled Liposomes for Targeting Drug Therapy of Hepatic Fibrosis in Rats

“…Small peptides have the advantage of being chemically defined, and they are also able to be manufactured in large quantities and at high purity without biological contaminants. They can be selected for specific targets with "one-bead one-compound" combinatorial libraries (Aina et al, 2005). The cyclic peptide C*GRGDSPC* has been shown to specifically inhibit the attachment of collagen type VI to cells (Marcelino and McDevitt, 1995).…”

Discovery of specific targeting ligands as the biomarkers for colorectal cancer

“…Using a reversible polyethylene glycol (PEG)-based disulfide cross-linked micelle derivatized with cholic acid (PEG 5k -Cys 4-CA 8 telodendrimers), hydrophobic drugs were encapsulated in the micelle core, and triggered for release at the tumor site and inside the cancer cells with high reductive potential [23]. Furthermore, such micelles, when conjugated to ovarian cancer binding ligands (discovered through OBOC library screening) and loaded with PTX, exhibit superior antitumor activity and lower systemic toxicity profile in nude mice bearing ovarian cancer tumor xenografts, when compared with equivalent doses of nontargeted PTX nanoparticles, as well as clinical PTX formulation (Taxol) [35].…”

“…Current reported studies have focused primarily on RGD-based peptides that target the α5β1 integrin [3][4][5], but the binding is not specific. Available test kits will be used to help identify the nature of the receptor and to determine the specificity of this binding [23]. Work is currently underway in our laboratory to evaluate the binding profile of CRC-9 and CRC-6 to cancer tissues obtained directly from primary human CRC tumors as well as a series of benign and precancerous lesions future science group www.futuremedicine.com (such as ulcer, adenoma, polyp and etc.).…”

“…Cyclization was carried out using CLEAR-OX resin (Peptides Intl, KY, USA) and the crude cyclized peptide was purified using reverse phase HPLC. The purity and molecular weight of peptides were characterized using analytical HPLC and mass spectrometry, respectively [23][24][25].…”

Potential of phage-displayed peptide library technology to identify functional targeting peptides

“…A search of present literature published between 2005 and 2006 revealed > 30 papers that disclose the identification of peptides using phage display, which were demonstrated to specifically target proteins in vitro. The technology has been used in attempts to develop novel targeting therapeutics or diagnostic reagents for human cancers [23,[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58], HIV infection [59,60], human papilloma virus infection [61], obesity [62], bacterial infection [63][64][65][66], parasitic infection [67], autoimmune disorders [68], thrombosis and inflammation [69,70], Alzheimer's disease [71] and increasing vaccine efficacy [72]. However, the in vivo therapeutic efficacy of these novel peptides remains to be determined.…”