Site-directed perturbation of protein kinase C- integrin interaction blocks carcinoma cell chemotaxis.
Polarized cell movement is an essential requisite for cancer metastasis; thus, interference with the tumor cell motility machinery would significantly modify its metastatic behavior. Protein kinase C alpha (PKC alpha) has been implicated in the promotion of a migratory cell phenotype. We report that the phorbol ester-induced cell polarization and directional motility in breast carcinoma cells is determined by a 12-amino-acid motif (amino acids 313 to 325) within the PKC alpha V3 hinge domain. This motif is also required for a direct association between PKC alpha and beta 1 integrin. Efficient binding of beta 1 integrin to PKC alpha requires the presence of both NPXY motifs (Cyto-2 and Cyto-3) in the integrin distal cytoplasmic domains. A cell-permeant inhibitor based on the PKC-binding sequence of beta 1 integrin was shown to block both PKC alpha-driven and epidermal growth factor (EGF)-induced chemotaxis. When introduced as a minigene by retroviral transduction into human breast carcinoma cells, this inhibitor caused a striking reduction in chemotaxis towards an EGF gradient. Taken together, these findings identify a direct link between PKC alpha and beta 1 integrin that is critical for directed tumor cell migration. Importantly, our findings outline a new concept as to how carcinoma cell chemotaxis is enhanced and provide a conceptual basis for interfering with tumor cell dissemination.
Richard Dimbleby/Cancer Research UK Department of Cancer Research, GKT School of Medicine, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
Maddy
M
Parsons
Melanie D
MD
Keppler
Adam
A
Kline
Anthea
A
Messent
Martin J
MJ
Humphries
Ruth
R
Gilchrist
Ian R
IR
Hart
Corinne
C
Quittau-Prevostel
William E
WE
Hughes
Peter J
PJ
Parker
Tony
T
Ng
D020816:Amino Acid Motifs; D051943:Antennapedia Homeodomain Protein; D017209:Apoptosis / Q000502:physiology; D001665:Binding Sites; D001943:Breast Neoplasms / Q000473:pathology / Q000503:physiopathology*; D002633:Chemotaxis / Q000502:physiology*; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D020287:In Situ Nick-End Labeling; D019012:Integrin beta1 / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009687:Nuclear Proteins; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014157:Transcription Factors; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
D051943:Antennapedia Homeodomain Protein; D018398:Homeodomain Proteins; D019012:Integrin beta1; D007527:Isoenzymes; D009687:Nuclear Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha