RT Journal Article
SR Electronic
T1 Antiproliferative Effects of CDK4/6 Inhibition in <em>CDK4</em>-Amplified Human Liposarcoma <em>In Vitro</em> and <em>In Vivo</em>
JF Molecular Cancer Therapeutics
JO Mol Cancer Ther
FD American Association for Cancer Research
SP 2184
OP 2193
DO 10.1158/1535-7163.MCT-14-0387
VO 13
IS 9
A1 Zhang, Yi-Xiang
A1 Sicinska, Ewa
A1 Czaplinski, Jeffrey T.
A1 Remillard, Stephen P.
A1 Moss, Samuel
A1 Wang, Yuchuan
A1 Brain, Christopher
A1 Loo, Alice
A1 Snyder, Eric L.
A1 Demetri, George D.
A1 Kim, Sunkyu
A1 Kung, Andrew L.
A1 Wagner, Andrew J.
YR 2014
UL http://mct.aacrjournals.org/content/13/9/2184.abstract
AB Well-differentiated/dedifferentiated liposarcomas (WD/DDLPS) are among the most common subtypes of soft tissue sarcomas. Conventional systemic chemotherapy has limited efficacy and novel therapeutic strategies are needed to achieve better outcomes for patients. The cyclin-dependent kinase 4 (CDK4) gene is highly amplified in more than 95% of WD/DDLPS. In this study, we explored the role of CDK4 and the effects of NVP-LEE011 (LEE011), a novel selective inhibitor of CDK4/CDK6, on a panel of human liposarcoma cell lines and primary tumor xenografts. We found that both CDK4 knockdown by siRNA and inhibition by LEE011 diminished retinoblastoma (RB) phosphorylation and dramatically decreased liposarcoma cell growth. Cell-cycle analysis demonstrated arrest at G0–G1. siRNA-mediated knockdown of RB rescued the inhibitory effects of LEE011, demonstrating that LEE011 decreased proliferation through RB. Oral administration of LEE011 to mice bearing human liposarcoma xenografts resulted in approximately 50% reduction in tumor 18F-fluorodeoxyglucose uptake with decreased tumor biomarkers, including RB phosphorylation and bromodeoxyuridine incorporation in vivo. Continued treatment inhibited tumor growth or induced regression without detrimental effects on mouse weight. After prolonged continuous dosing, reestablishment of RB phosphorylation and cell-cycle progression was noted. These findings validate the critical role of CDK4 in maintaining liposarcoma proliferation through its ability to inactivate RB function, and suggest its potential function in the regulation of survival and metabolism of liposarcoma, supporting the rationale for clinical development of LEE011 for the treatment of WD/DDLPS. Mol Cancer Ther; 13(9); 2184–93. ©2014 AACR.This article is featured in Highlights of This Issue, p. 2139