Targeting the cyclin E-Cdk-2 complex represses lung cancer growth by triggering anaphase catastrophe.
OBJECTIVE
Cyclin-dependent kinases (Cdk) and their associated cyclins are targets for lung cancer therapy and chemoprevention given their frequent deregulation in lung carcinogenesis. This study uncovered previously unrecognized consequences of targeting the cyclin E-Cdk-2 complex in lung cancer.


METHODS
Cyclin E, Cdk-1, and Cdk-2 were individually targeted for repression with siRNAs in lung cancer cell lines. Cdk-2 was also pharmacologically inhibited with the reversible kinase inhibitor seliciclib. Potential reversibility of seliciclib effects was assessed in washout experiments. Findings were extended to a large panel of cancer cell lines using a robotic-based platform. Consequences of cyclin E-Cdk-2 inhibition on chromosome stability and on in vivo tumorigenicity were explored as were effects of combining seliciclib with different taxanes in lung cancer cell lines.


RESULTS
Targeting the cyclin E-Cdk-2 complex, but not Cdk-1, resulted in marked growth inhibition through the induction of multipolar anaphases triggering apoptosis. Treatment with the Cdk-2 kinase inhibitor seliciclib reduced lung cancer formation in a murine syngeneic lung cancer model and decreased immunohistochemical detection of the proliferation markers Ki-67 and cyclin D1 in lung dysplasia spontaneously arising in a transgenic cyclin E-driven mouse model. Combining seliciclib with a taxane resulted in augmented growth inhibition and apoptosis in lung cancer cells. Pharmacogenomic analysis revealed that lung cancer cell lines with mutant ras were especially sensitive to seliciclib.


CONCLUSIONS
Induction of multipolar anaphases leading to anaphase catastrophe is a previously unrecognized mechanism engaged by targeting the cyclin E-Cdk-2 complex. This exerts substantial antineoplastic effects in the lung.
Galimberti
Fabrizio
F
Department of Pharmacology and Toxicology, Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, New Hampshire 03755, USA.
Thompson
Sarah L
SL
Liu
Xi
X
Li
Hua
H
Memoli
Vincent
V
Green
Simon R
SR
DiRenzo
James
J
Greninger
Patricia
P
Sharma
Sreenath V
SV
Settleman
Jeff
J
Compton
Duane A
DA
Dmitrovsky
Ethan
E
D000705:Anaphase / Q000187:drug effects*; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019927:Cyclin E / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000077143:Docetaxel; D016503:Drug Delivery Systems; D008175:Lung Neoplasms / Q000188:drug therapy*; D051379:Mice; D008822:Mice, Transgenic; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D000077546:Roscovitine; D043823:Taxoids / Q000494:pharmacology
D000970:Antineoplastic Agents; D019927:Cyclin E; D047428:Protein Kinase Inhibitors; D011687:Purines; D043823:Taxoids; D000077546:Roscovitine; D000077143:Docetaxel; D051357:Cyclin-Dependent Kinase 2