PND-1186 FAK inhibitor selectively promotes tumor cell apoptosis in three-dimensional environments.
Tumor cells can grow in an anchorage-independent manner. This is mediated in part through survival signals that bypass normal growth restraints controlled by integrin cell surface receptors. Focal adhesion kinase (FAK) is a cytoplasmic protein-tyrosine kinase that associates with integrins and modulates various cellular processes including growth, survival, and migration. As increased FAK expression and tyrosine phosphorylation are associated with tumor progression, inhibitors of FAK are being tested for anti-tumor effects. Here, we analyze PND-1186, a substituted pyridine reversible inhibitor of FAK activity with a 50% inhibitory concentration (IC50) of 1.5 nM in vitro. PND-1186 has an IC50 of ~100 nM in breast carcinoma cells as determined by anti-phospho-specific immunoblotting to FAK Tyr-397. PND-1186 did not alter c‑Src or p130Cas tyrosine phosphorylation in adherent cells, yet functioned to restrain cell movement. Notably, 1.0 µM PND-1186 (>5-fold above IC50) had limited effects on cell proliferation. However, under non-adherent conditions as spheroids and as colonies in soft agar, 0.1 µM PND-1186 blocked FAK and p130Cas tyrosine phosphorylation, promoted caspase-3 activation, and triggered cell apoptosis. PND-1186 inhibited 4T1 breast carcinoma subcutaneous tumor growth correlated with elevated tumor cell apoptosis and caspase 3 activation. Addition of PND-1186 to the drinking water of mice was well tolerated and inhibited ascites- and peritoneal membrane-associated ovarian carcinoma tumor growth associated with the inhibition of FAK Tyr-397 phosphorylation. Our results with low-level PND-1186 treatment support the conclusion that FAK activity selectively promotes tumor cell survival in three-dimensional environments.
Department of Reproductive Medicine, Moores Cancer Center, University of California-San Diego, La Jolla, CA USA.
Isabelle
I
Tanjoni
Colin
C
Walsh
Sean
S
Uryu
Alok
A
Tomar
Ju-Ock
JO
Nam
Ainhoa
A
Mielgo
Ssang-Taek
ST
Lim
Congxin
C
Liang
Marcel
M
Koenig
Connie
C
Sun
Neela
N
Patel
Cheni
C
Kwok
Gerald
G
McMahon
Dwayne G
DG
Stupack
David D
DD
Schlaepfer
D000631:Aminopyridines / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D050719:Crk-Associated Substrate Protein / Q000378:metabolism; D005260:Female; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010766:Phosphorylation / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D018874:Spheroids, Cellular / Q000187:drug effects; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014443:Tyrosine / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D019061:src-Family Kinases / Q000037:antagonists & inhibitors
D000631:Aminopyridines; D000970:Antineoplastic Agents; D050719:Crk-Associated Substrate Protein; C559284:PND 1186; D014443:Tyrosine; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019061:src-Family Kinases; D053148:Caspase 3