Effects of peptidic antagonists of Grb2-SH2 on human breast cancer cells.
The growth factor receptor-bound protein Src homology 2 (Grb2-SH2) plays an important role in the oncogenic Ras signaling pathway, which involves in cell proliferation and differentiation. Therefore, the antagonist of Grb2-SH2 has become a potential target for developing anticancer agents. Recently, we discovered a peptide 1 (Fmoc-Glu-Tyr-Aib-Asn-NH(2)) with high affinity for the Grb2-SH2 domain by using surface plasmon resonance (SPR)-biosensor technology. Herein, we report the further design of the lead peptide 1 by addition of an Arg-Gly-Asp sequence to 1 to enhance binding to Grb2-SH2 and inducing apoptosis in cancer cells. Both the linear and cyclic analogs of the newly designed compound were prepared along with an analog in which the N(alpha)-Fmoc group was removed. These peptide analogs were assayed for their affinity for the Grb2-SH2, their antiproliferative effect on human breast cancer cells, their specificity for cancer cells, and their effects on cytotoxicity and the cell cycle. MCF-7 and MDA-MB-453 breast cancer cells were treated with various concentrations of each peptide. The cell viability and cytotoxicity of peptide-treated cells were determined by using the cell proliferation kit (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-tetrazolium bromide, MTT) and cytotoxicity kit (lactate dehydrogenase, LDH), respectively. Effects of peptides on the cell cycle progression of cancer cells and apoptosis were analyzed by using flow cytometry. Results demonstrated that the peptide analog 2 (H-Arg-Gly-Asp-Glu-Tyr-Aib-Asn-Arg-Gly-Asp-NH(2)) had anti-proliferative effects on MCF-7 and MDA-MB-453 cells with an IC(50) of 45.7 microM and 47.4 microM, respectively. The cytotoxicity and percentage of sub-G1 in the cell cycle were increased in these cancer cells when cells were treated with higher concentration of the Arg-Gly-Asp-containing peptide 2. These results provide important information for the development of anti-cancer agents.
Chen
Chiu-Heng
CH
Department of Chemistry, Tunghai University, Taichung, Taiwan, ROC.
Chen
Meng-Kai
MK
Jeng
Kee-Ching G
KC
Lung
Feng-Di T
FD
D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D048708:Cell Growth Processes / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D051380:GRB2 Adaptor Protein / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry; D007700:Kinetics; D010455:Peptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D010456:Peptides, Cyclic / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D017434:Protein Structure, Tertiary
D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D055767:Immobilized Proteins; D010455:Peptides; D010456:Peptides, Cyclic