Antitumour effects of PLC-gamma1-(SH2)2-TAT fusion proteins on EGFR/c-erbB-2-positive breast cancer cells.
Due to its pivotal role in the growth factor-mediated tumour cell migration, the adaptor protein phospholipase C-gamma1 (PLC-gamma1) is an appropriate target to block ultimately the spreading of EGFR/c-erbB-2-positive tumour cells, thereby minimising metastasis formation. Here, we present an approach to block PLC-gamma1 activity by using protein-based PLC-gamma1 inhibitors consisting of PLC-gamma1 SH2 domains, which were fused to the TAT-transduction domain to ensure a high protein transduction efficiency. Two proteins were generated containing one PLC-gamma1-SH2-domain (PS1-TAT) or two PLC-gamma1-SH2 domains (PS2-TAT). PS2-TAT treatment of the EGFR/c-erbB-2-positive cell line MDA-HER2 resulted in a reduction of the EGF-mediated PLC-gamma1 tyrosine phosphorylation of about 30%, concomitant with a complete abrogation of the EGF-driven calcium influx. In addition to this, long-term PS2-TAT treatment both reduces the EGF-mediated migration of about 75% combined with a markedly decreased time locomotion of single MDA-HER2 cells as well as decreases the proliferation of MDA-HER2 cells by about 50%. Due to its antitumoral capacity on EGFR/c-erbB-2-positive breast cancer cells, we conclude from our results that the protein-based PLC-gamma1 inhibitor PS2-TAT may be a means for novel adjuvant antitumour strategies to minimise metastasis formation because of the blockade of cell migration and proliferation.
Katterle
Y
Y
Institute of Immunology, University of Witten/Herdecke, Stockumer Strasse 10, 58448 Witten, Germany.
Brandt
B H
BH
Dowdy
S F
SF
Niggemann
B
B
Zänker
K S
KS
Dittmar
T
T
D000236:Adenoma / Q000235:genetics* / Q000473:pathology*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D002455:Cell Division; D002465:Cell Movement; D015696:Gene Products, tat; D018773:Genes, erbB-1 / Q000235:genetics*; D006801:Humans; D009362:Neoplasm Metastasis / Q000517:prevention & control*; D051966:Phospholipase C gamma; D011993:Recombinant Fusion Proteins / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000494:pharmacology*
D015696:Gene Products, tat; D011993:Recombinant Fusion Proteins; D010738:Type C Phospholipases; D051966:Phospholipase C gamma