PAI-1 and functional blockade of SNAI1 in breast cancer cell migration.
BACKGROUND
Snail, a family of transcriptional repressors implicated in cell movement, has been correlated with tumour invasion. The Plasminogen Activation (PA) system, including urokinase plasminogen activator (uPA), its receptor and its inhibitor, plasminogen activator inhibitor type 1(PAI-1), also plays a key role in cancer invasion and metastasis, either through proteolytic degradation or by non-proteolytic modulation of cell adhesion and migration. Thus, Snail and the PA system are both over-expressed in cancer and influence this process. In this study we aimed to determine if the activity of SNAI1 (a member of the Snail family) is correlated with expression of the PA system components and how this correlation can influence tumoural cell migration.


METHODS
We compared the invasive breast cancer cell-line MDA-MB-231 expressing SNAI1 (MDA-mock) with its derived clone expressing a dominant-negative form of SNAI1 (SNAI1-DN). Expression of PA system mRNAs was analysed by cDNA microarrays and real-time quantitative RT-PCR. Wound healing assays were used to determine cell migration. PAI-1 distribution was assessed by immunostaining.


RESULTS
We demonstrated by both cDNA microarrays and real-time quantitative RT-PCR that the functional blockade of SNAI1 induces a significant decrease of PAI-1 and uPA transcripts. After performing an in vitro wound-healing assay, we observed that SNAI1-DN cells migrate more slowly than MDA-mock cells and in a more collective manner. The blockade of SNAI1 activity resulted in the redistribution of PAI-1 in SNAI1-DN cells decorating large lamellipodia, which are commonly found structures in these cells.


CONCLUSIONS
In the absence of functional SNAI1, the expression of PAI-1 transcripts is decreased, although the protein is redistributed at the leading edge of migrating cells in a manner comparable with that seen in normal epithelial cells.
Fabre-Guillevin
Elizabeth
E
DYNAMIC Team, IBISC FRE 3190 CNRS - Université d'Evry Val d'Essonne, Genopole, Evry 91000, France.
Malo
Michel
M
Cartier-Michaud
Amandine
A
Peinado
Hector
H
Moreno-Bueno
Gema
G
Vallée
Benoît
B
Lawrence
Daniel A
DA
Palacios
José
J
Cano
Amparo
A
Barlovatz-Meimon
Georgia
G
Charrière-Bertrand
Cécile
C
D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D005260:Female; D005455:Fluorescent Antibody Technique; D020869:Gene Expression Profiling; D005799:Genes, Dominant; D006801:Humans; D007124:Immunoenzyme Techniques; D020411:Oligonucleotide Array Sequence Analysis; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D011554:Pseudopodia / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism; D014945:Wound Healing
D015820:Cadherins; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; C051321:SERPINE1 protein, human; C000604407:SNAI1 protein, human; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D014568:Urokinase-Type Plasminogen Activator