A soluble truncated cadherin induces breast cancer cell apoptosis and growth inhibition.
OBJECTIVE
To identify the characteristics and function of the truncated cadherin cDNA which encodes a soluble molecule containing the sequence of VE-cadherin extracellular domain repeats from repeat 1 to 4 (designated as CED1-4) and a secreting signal peptide at N terminal.


METHODS
A pMSCV/CED1-4 vector was constructed. Recombinant retrovirus ReCED1-4 and ReEmpty were produced by 293 package cells and transfected into MDA-MB435 human breast cancer cells. The expression of CED1-4 in transfectants and their supernatant was analyzed by RT-PCR and Western blot, respectively. MDA-MB435 cell proliferation assays were performed in vitro and in vivo. CED-14-induced apoptosis was demonstrated using Annexin V binding, TUNEL and caspase 3 assays. The expression of integrin beta1 and c-fos mRNA was detected by RT-PCR.


RESULTS
The constructed soluble CED1-4 encoded 484 amino acids and a secreting signal peptide (27 amino acids). CED1-4 was expressed by MDA-MB435/CED1-4 cells, and detected in the supernatant of CED1-4 tranfectants. CED1-4 transfection significantly inhibited the growth of MDA-MB435 cells in vitro and in vivo. About 22-fold increase in the early apoptotic cells in MDA-MB435/CED1-4 cells was observed as compared with MDA-MB435/empty cells. Increased activity of caspase 3 in MDA-MB435/CED1-4 cells was more than two times as compared with that of the control cells. Interestingly, integrin beta1 transcriptional level in MDA-MB435/CED1-4 cells was down-regulated as compared with control cells. The resistance of fibronectin to CED1-4 apoptotic inducibility was confirmed by detection of caspase 3. The blockage of c-fos transcriptional expression was detected in MDA-MB435/CED1-4 cells.


CONCLUSIONS
The soluble truncated cadherin may be considered an apoptotic inducer and growth inhibitor in the MDA-MB435 breast carcinoma cell line. Down-regulation of integrin beta1 and blockage of c-fos expression may be related to CED1-4-induced apoptosis and growth inhibition.
Shi
Xiao-Yu
XY
INSERM, Institut Universitaire d'Hématologie, U553, Université Paris 7, 75010 Paris, France.
Lu
He
H
Li
Wen-Lin
WL
Tang
Hong-Lin
HL
Xiong
Jian-Jun
JJ
Zhang
Ji-Qing
JQ
Opolon
Paule
P
Legrand
Chantal
C
Perricaudet
Michel
M
Li
Hong
H
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D015820:Cadherins / Q000096:biosynthesis / Q000235:genetics*; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism*; D053148:Caspase 3 / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D003001:Cloning, Molecular; D015536:Down-Regulation / Q000187:drug effects; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D018014:Gene Transfer Techniques; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008819:Mice, Nude; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012995:Solubility; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
D048868:Adaptor Proteins, Signal Transducing; D015820:Cadherins; C108257:ITGB1BP1 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D011994:Recombinant Proteins; D053148:Caspase 3