Maspin functions as tumor suppressor by increasing cell adhesion to extracellular matrix in prostate tumor cells.
OBJECTIVE
Maspin, a unique member of the serine protease inhibitor family, shows tumor suppressing activity for breast cancer progression and metastasis. Few studies have directly linked maspin function to prostate cancer. We used prostate tumor cells derived from the TRAMP (transgenic adenocarcinoma of mouse prostate) prostate tumor model to study the tumor suppressive function of maspin in prostate cancer.


METHODS
Maspin cDNA was introduced via a retroviral plasmid into TRAMP C2N prostate tumor cells, which are aggressive and invasive in nature. We investigated the tumorigenesis of these stable cell lines in vitro by assessing the growth rate, anchorage independence and adhesion to extracellular matrix proteins such as fibronectin and laminin.


RESULTS
Stable cell lines expressing maspin had decreased tumorigenic potential, as assessed by anchorage independent growth in soft agar assay compared with controls. Maspin stable transfectants showed decreased metastatic potential, as evaluated by modified Boyden chamber assay and increased adhesion to fibronectin and laminin.


CONCLUSIONS
Our study confirms that maspin has a tumor suppressive role not only in breast cancer, but also in prostate cancer. The data in this study suggest that maspin can decrease the tumorigenic and metastatic potential of prostate tumors, most probably by remodeling cell-extracellular matrix interactions or triggering extracellular matrix mediated signaling pathways that negatively regulate tumor migration and invasion.
Abraham
Shaji
S
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.
Zhang
Weiguo
W
Greenberg
Norman
N
Zhang
Ming
M
D000230:Adenocarcinoma / Q000503:physiopathology*; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002455:Cell Division; D005109:Extracellular Matrix / Q000502:physiology*; D005353:Fibronectins / Q000502:physiology; D016147:Genes, Tumor Suppressor; D007797:Laminin / Q000502:physiology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D011471:Prostatic Neoplasms / Q000235:genetics / Q000503:physiopathology*; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D015842:Serine Proteinase Inhibitors / Q000235:genetics / Q000502:physiology*; D015843:Serpins / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000502:physiology; D014410:Tumor Stem Cell Assay
D005353:Fibronectins; D007797:Laminin; D011506:Proteins; C085344:SERPIN-B5; D015842:Serine Proteinase Inhibitors; D015843:Serpins