Pero S C, Shukla G S, Cookson M M, Flemer S, Krag D N
Department of Surgery, Vermont Cancer Comprehensive Center, College of Medicine, University of Vermont, Burlington, VT 05405, USA.
Br J Cancer. 2007 May 21;96(10):1520-5. doi: 10.1038/sj.bjc.6603732. Epub 2007 Apr 10.
Grb7 has potential importance in the progression of cancer. We have previously identified a novel peptide that binds to the SH2 domain of Grb7 and inhibits its association with several different receptor tyrosine kinases. We have synthesised the Grb7 peptide, G7-18NATE, with two different cell penetrating peptides, Penetratin and Tat. In this study, we have shown that both Penetratin- and Tat-conjugated G7-18NATE peptides are able to inhibit the proliferation of SK-BR-3, ZR-75-30, MDA-MB-361 and MDA-MB-231 breast cancer cells. There was no significant effects on breast cancer MCF-7cells, non-malignant MCF 10A or 3T3 cells. In addition, there was no significant inhibition of proliferation by Penetratin or Tat alone or by their conjugates with arbitrary peptide sequence in any of the cell lines tested. We determined the EC50 of G7-18NATE-P peptide for SK-BR-3 cell proliferation to be 7.663 x 10(-6) M. Co-treatment of G7-18NATE-P peptide plus Doxorubicin in SK-BR-3 breast cancer cells resulted in an additional inhibition of proliferation, resulting in 56 and 84% decreases in the Doxorubicin EC50 value in the presence of 5 x 10(-6) and 1.0 x 10(-5) M G7-18NATE-P peptide, respectively. Importantly, the co-treatment with Doxorubicin and the delivery peptide did not change the Doxorubicin EC50. Since Grb7 associates with ErbB2, we assessed whether the peptide inhibitor would have a combined effect with a molecule that targets ErbB2, Herceptin. Co-treatment of Herceptin plus 1.0 x 10(-5) M G7-18NATE-P peptide in SK-BR-3 cells resulted in a 46% decrease in the Herceptin EC50 value and no decrease following the co-treatment with Herceptin and penetratin alone. This Grb7 peptide has potential to be developed as a therapeutic agent alone, in combination with traditional chemotherapy, or in combination with other targeting molecules.
Grb7在癌症进展中具有潜在重要性。我们之前鉴定出一种与Grb7的SH2结构域结合并抑制其与多种不同受体酪氨酸激酶结合的新型肽。我们已将Grb7肽G7 - 18NATE与两种不同的细胞穿透肽Penetratin和Tat进行了合成。在本研究中，我们表明Penetratin和Tat偶联的G7 - 18NATE肽均能够抑制SK - BR - 3、ZR - 75 - 30、MDA - MB - 361和MDA - MB - 231乳腺癌细胞的增殖。对乳腺癌MCF - 7细胞、非恶性MCF 10A或3T3细胞没有显著影响。此外，在任何测试的细胞系中，单独的Penetratin或Tat或它们与任意肽序列的偶联物对细胞增殖均无显著抑制作用。我们确定G7 - 18NATE - P肽对SK - BR - 3细胞增殖的EC50为7.663×10(-6) M。在SK - BR - 3乳腺癌细胞中，G7 - 18NATE - P肽与阿霉素联合处理导致增殖的额外抑制，在存在5×10(-6)和1.0×10(-5) M G7 - 18NATE - P肽时，阿霉素的EC50值分别降低了56%和84%。重要的是，与阿霉素和递送肽联合处理并未改变阿霉素的EC50。由于Grb7与ErbB2相关联，我们评估了该肽抑制剂是否会与靶向ErbB2的分子赫赛汀产生联合作用。在SK - BR - 3细胞中，赫赛汀与1.0×10(-5) M G7 - 18NATE - P肽联合处理导致赫赛汀的EC50值降低了46%，而赫赛汀与单独的Penetratin联合处理后则没有降低。这种Grb7肽有潜力单独开发为治疗剂，或与传统化疗联合使用，或与其他靶向分子联合使用。
