Development of leiomyosarcoma of the uterus in MMTV-CR-1 transgenic mice.
Overexpression of Cripto-1 (CR-1) in FVB/N mice using the MMTV-LTR promoter results in increased mammary tumourigenesis in these female transgenic mice (MMTV-CR-1). Here, we characterize uterine tumours that developed in 15/76 (19.7%) of MMTV-CR-1 female nulliparous or multiparous mice during 24 months of observation compared with 0/33 (0%) of FVB/N normal control mice observed during the same time period (p < 0.01). The uterine tumours collected from the MMTV-CR-1 mice were classified as leiomyosarcomas and found to express the CR-1 transgene by polymerase chain reaction analysis and immunohistochemistry. Detection by western blot analysis showed higher levels of phosphorylated (P) forms of c-src, Akt, GSK-3beta, and dephosphorylated (DP)-beta-catenin in lysates from MMTV-CR-1 uterine leiomyosarcomas in comparison with lysates from normal control FVB/N uteri. Immunostaining showed increased nuclear localization of beta-catenin in the MMTV-CR-1 uterine leiomyosarcomas. Increased immunostaining for CR-1 was detected in 9/13 (69.2%) cases of human leiomyosarcoma compared with staining in 3/15 (20%) human leiomyoma sections. Stronger immunostaining for P-src, P-Akt, P-GSK-3beta and increased nuclear localization of beta-catenin was also seen in human leiomyosarcomas in comparison with leiomyomas. Normal human uterine smooth muscle (UtSM) cells treated with exogenous soluble rhCR-1 showed increased levels of P-src, P-Akt, P-GSK-3beta and dephosphorylated (DP)-beta-catenin and increased proliferation (p < 0.05) and migration (p < 0.01) in comparison with untreated control UtSM cells. Inhibitors against c-src, Akt or beta-catenin, individually or in combination, significantly reduced CR-1-induced migration. These results suggest a role for CR-1 during uterine tumourigenesis either directly by activating c-src and Akt and/or via cross-talk with the canonical Wnt signalling pathway, as suggested by the increased expression of P-GSK-3beta, DP-beta-catenin, and increased nuclear localization of beta-catenin in human and MMTV-CR-1 mice leiomyosarcomas.
Strizzi
L
L
Mammary Biology and Tumorigenesis Laboratory, National Cancer Institute, Bethesda, MD 20892, USA.
Bianco
C
C
Hirota
M
M
Watanabe
K
K
Mancino
M
M
Hamada
S
S
Raafat
A
A
Lawson
S
S
Ebert
A D
AD
D'Antonio
A
A
Losito
S
S
Normanno
N
N
Salomon
D S
DS
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D058851:GPI-Linked Proteins; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D036341:Intercellular Signaling Peptides and Proteins; D007890:Leiomyosarcoma / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction; D014594:Uterine Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D051155:Wnt1 Protein / Q000032:analysis / Q000235:genetics / Q000378:metabolism
D058851:GPI-Linked Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; C070636:TDGF1 protein, human; D051155:Wnt1 Protein; D004815:Epidermal Growth Factor