Integrin-linked kinase expression increases with prostate tumor grade.
OBJECTIVE
Integrin-linked kinase (ILK) overexpression can suppress anoikis, promote anchorage-independent cell cycle progression, and induce tumorigenesis and invasion. Inhibition of ILK in prostatic adenocarcinoma (CaP) cells elicits cell cycle arrest and induces apoptosis. Furthermore, ILK expression increases with androgen-independent progression of human CaP cell lines, suggesting that increased ILK expression may be associated with CaP progression.


METHODS
To assess whether ILK expression may be related to CaP development and/or progression, we have evaluated ILK expression by immunohistochemistry in 100 human prostate tissues.


RESULTS
We show that ILK expression increases significantly with CaP progression. ILK immunostaining is specifically increased in high-grade, primary human CaP relative to adjacent benign prostatic hyperplasia (P < 0.001), benign prostatic hyperplasia from patients without cancer (P < 0.002), and low-grade CaP (P = 0.003). ILK overexpression is specifically associated with the increased proliferative index (P = 0.001) that typifies CaP progression. Strikingly, intense uniform ILK immunostaining was inversely related to 5-year patient survival (P = 0.004).


CONCLUSIONS
ILK expression increases dramatically with CaP progression. ILK expression is also specifically related to the disproportionately increased proliferative index that contributes to the net gain of CaP cells during progression. Finally, enhanced ILK expression is inversely related to 5-year patient survival. These data therefore implicate increased ILK expression in prostate tumor progression.
Graff
J R
JR
Cancer Division, Lilly Research Labs, Eli Lilly and Company, Indianapolis, Indiana 46285, USA. graff_jeremy@lilly.com
Deddens
J A
JA
Konicek
B W
BW
Colligan
B M
BM
Hurst
B M
BM
Carter
H W
HW
Carter
J H
JH
D000230:Adenocarcinoma / Q000201:enzymology / Q000473:pathology*; D017209:Apoptosis; D002455:Cell Division; D018450:Disease Progression; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008940:Mitotic Index; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000473:pathology*; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis*; D000099200:Scaffold Protein ILK
D019394:Ki-67 Antigen; D017346:Protein Serine-Threonine Kinases; D000099200:Scaffold Protein ILK