Decreased galectin-3 expression in prostate cancer.
BACKGROUND
Galectin-3 is a carbohydrate-binding protein whose level of expression has been shown to be correlated with metastatic potential in a number of different tumor types. The purpose of this investigation was to examine galectin-3 expression in several tumorigenic and nontumorigenic prostate cell lines and prostate tissue samples.


METHODS
The expression of galectin-3 in cell lines and tissue samples was evaluated by tissue immunohistochemistry and Western blot analysis.


RESULTS
Human cell lines PC-3M, PC-3, DU-145, PrEC-1, and MCF10A demonstrated the presence of galectin-3. Galectin-3 was not detected in TSU-pr1 and LNCaP by Western blot analysis. We furthered our studies by examining a series of human prostate tissue samples for expression of galectin-3. Overall, approximately 60-70% of the normal tissue examined demonstrated heterogenous expression of galectin-3. In stage II tumors, however, there was a dramatic decrease in galectin-3 expression in both PIN and tumor sections, with only 10.5% (2/19) of these samples expressing this protein. Stage III tumors also demonstrated a decreased expression of galectin-3, although this downregulation was not as dramatic, with 35% of PIN samples and 52% of tumor tissue expressing galectin-3 (P < 0.01).


CONCLUSIONS
These data demonstrate that galectin-3 is downregulated in prostate cancer. The altered downregulation pattern of galectin-3 observed between tumor stages suggests different roles for galectin-3 in the progression of prostate cancer.
Pacis
R A
RA
University of Michigan Comprehensive Cancer Center, Division of Hematology/Oncology, Department of Internal Medicine, St. John's Hospital, Detroit, Michigan, USA.
Pilat
M J
MJ
Pienta
K J
KJ
Wojno
K
K
Raz
A
A
Hogan
V
V
Cooper
C R
CR
D000943:Antigens, Differentiation / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D015153:Blotting, Western; D002460:Cell Line; D037502:Galectin 3; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011467:Prostate / Q000166:cytology / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000737:chemistry / Q000235:genetics / Q000473:pathology*; D014407:Tumor Cells, Cultured
D000943:Antigens, Differentiation; D037502:Galectin 3