Peptide name : Transferrin receptor (TfR)-lytic hybrid peptide

Source/Organism : Transferrin receptor (TfR)

Linear/Cyclic : Linear

Chirality : Mix

Peptide length: 32

C-terminal modification: Linear

N-terminal modification : Free

Non-natural peptide information: None

Assay type : WST-1 assay

Assay time : 72h

Activity : IC50 : 6.3 µM

Cell line : SF-295

Cancer type : Brain tumor

Other activity : Not found

Amino acid composition bar chart :

Molecular mass : 3705.6798 Dalton

Aliphatic index : 0.821

Instability index : 22.9531

Hydrophobicity (GRAVY) : -0.296

Isoelectric point : 11.505

Charge (pH 7) : 8.4774

Aromaticity : 0.062

Molar extinction coefficient (cysteine, cystine): (11000, 11000)

Hydrophobic/hydrophilic ratio : 1.7

hydrophobic moment : -0.057

Missing amino acid : C,Q,I,E,F,D,Y,N,A

Most occurring amino acid : K

Most occurring amino acid frequency : 6

Least occurring amino acid : T

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.5, 0.2, 0.4)

SMILES Notation: CSCC[C@H](NC(=O)[C@@H]1CCCN1C(=O)[C@@H]1CCCN1C(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](Cc1c[nH]cn1)NC(=O)[C@@H](N)[C@@H](C)O)C(=O)N[C@@H](Cc1c[nH]c2ccccc12)C(=O)N[C@@H](CO)C(=O)N1CCC[C@H]1C(=O)N[C@H](C(=O)N[C@@H](Cc1c[nH]c2ccccc12)C(=O)N1CCC[C@H]1C(=O)NCC(=O)NCC(=O)NCC(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCCN)C(=O)O)C(C)C

1 : Kawamoto M, et al. A novel transferrin receptor-targeted hybrid peptide disintegrates cancer cell membrane to induce rapid killing of cancer cells. BMC Cancer. 2011; 11:359. doi: 10.1186/1471-2407-11-359

Paper title : A novel transferrin receptor-targeted hybrid peptide disintegrates cancer cell membrane to induce rapid killing of cancer cells.

Doi : https://doi.org/10.1186/1471-2407-11-359

Abstract : BACKGROUND: Transferrin receptor (TfR) is a cell membrane-associated glycoprotein involved in the cellular uptake of iron and the regulation of cell growth. Recent studies have shown the elevated expression levels of TfR on cancer cells compared with normal cells. The elevated expression levels of this receptor in malignancies, which is the accessible extracellular protein, can be a fascinating target for the treatment of cancer. We have recently designed novel type of immunotoxin, termed "hybrid peptide", which is chemically synthesized and is composed of target-binding peptide and lytic peptide containing cationic-rich amino acids components that disintegrates the cell membrane for the cancer cell killing. The lytic peptide is newly designed to induce rapid killing of cancer cells due to conformational change. In this study, we designed TfR binding peptide connected with this novel lytic peptide and assessed the cytotoxic activity in vitro and in vivo. METHODS: In vitro: We assessed the cytotoxicity of TfR-lytic hybrid peptide for 12 cancer and 2 normal cell lines. The specificity for TfR is demonstrated by competitive assay using TfR antibody and siRNA. In addition, we performed analysis of confocal fluorescence microscopy and apoptosis assay by Annexin-V binding, caspase activity, and JC-1 staining to assess the change in mitochondria membrane potential. In vivo: TfR-lytic was administered intravenously in an athymic mice model with MDA-MB-231 cells. After three weeks tumor sections were histologically analyzed. RESULTS: The TfR-lytic hybrid peptide showed cytotoxic activity in 12 cancer cell lines, with IC(50) values as low as 4.0-9.3 μM. Normal cells were less sensitive to this molecule, with IC(50) values > 50 μM. Competition assay using TfR antibody and knockdown of this receptor by siRNA confirmed the specificity of the TfR-lytic hybrid peptide. In addition, it was revealed that this molecule can disintegrate the cell membrane of T47D cancer cells just in 10 min, to effectively kill these cells and induce approximately 80% apoptotic cell death but not in normal cells. The intravenous administration of TfR-lytic peptide in the athymic mice model significantly inhibited tumor progression. CONCLUSIONS: TfR-lytic peptide might provide a potent and selective anticancer therapy for patients.