Antiproliferative effect of sulindac in colonic neoplasia prevention: role of COOH-terminal Src kinase.
Although the nonsteroidal anti-inflammatory drugs (NSAID) protection against colorectal cancer is well established, the molecular mechanisms remain unclear. We show herein that induction of the tumor suppressor gene COOH-terminal Src kinase (Csk) by NSAID is important for their antiproliferative and hence chemopreventive effects. In the azoxymethane-treated rat model of experimental colon carcinogenesis, sulindac treatment markedly induced Csk with a corresponding increase in inhibitory phosphorylation of Src (Tyr(527)). Sulindac-mediated Csk induction was replicated in the human colorectal cancer cell line HT-29, with a corresponding suppression of both Src kinase activity (63% of vehicle; P < 0.05) and E-cadherin tyrosine phosphorylation (an in vivo Src target). To determine the importance of Csk in NSAID antiproliferative activity, we stably transfected a Csk-specific short hairpin RNA (shRNA) vector into HT-29 cells, thereby blunting the sulindac-mediated Csk induction. These transfectants were significantly less responsive to the antiproliferative effect of sulindac sulfide (suppression of proliferating cell nuclear antigen was 21 +/- 2.3% in transfectants versus 45 +/- 4.23% in wild-type cells), with a corresponding mitigation of the sulindac-mediated G(1)-S-phase arrest (S-phase cells 48 +/- 3.6% versus 14 +/- 2.8% of vehicle respectively). Importantly, the Csk shRNA cells had a marked decrease in the cyclin-dependent kinase inhibitor p21(cip/waf1), a critical regulator of G(1)-S-phase progression (49% of wild-type cells). Moreover, although sulindac-mediated induction of p21(cip/waf1) was 113% in wild-type HT-29, this induction was alleviated in the Csk shRNA transfectants (65% induction; P < 0.01). Thus, this is the first demonstration that the antiproliferative activity of NSAID is modulated, at least partly, through the Csk/Src axis.
Kunte
Dhananjay P
DP
Feinberg School of Medicine at Northwestern University, Department of Internal Medicine, Evanston Northwestern Healthcare, 2650 Ridge Avenue, Suite G208, Evanston, IL 60201, USA.
Wali
Ramesh K
RK
Koetsier
Jennifer L
JL
Roy
Hemant K
HK
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001397:Azoxymethane; D000081247:CSK Tyrosine-Protein Kinase; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003106:Colon / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology / Q000517:prevention & control*; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D004790:Enzyme Induction / Q000187:drug effects; D019073:HT29 Cells; D006801:Humans; D008297:Male; D008954:Models, Biological; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D013467:Sulindac / Q000031:analogs & derivatives* / Q000494:pharmacology; D019061:src-Family Kinases
D000970:Antineoplastic Agents; D050759:Cyclin-Dependent Kinase Inhibitor p21; D013467:Sulindac; C025462:sulindac sulfide; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D001397:Azoxymethane