Skip to Content
Merck
  • Antiproliferative effects of CDK4/6 inhibition in CDK4-amplified human liposarcoma in vitro and in vivo.

Antiproliferative effects of CDK4/6 inhibition in CDK4-amplified human liposarcoma in vitro and in vivo.

Molecular cancer therapeutics (2014-07-17)
Yi-Xiang Zhang, Ewa Sicinska, Jeffrey T Czaplinski, Stephen P Remillard, Samuel Moss, Yuchuan Wang, Christopher Brain, Alice Loo, Eric L Snyder, George D Demetri, Sunkyu Kim, Andrew L Kung, Andrew J Wagner
ABSTRACT

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 (18)F-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.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Propidium iodide solution
Sigma-Aldrich
Sodium chloride, 99.999% trace metals basis
Supelco
Sodium chloride, reference material for titrimetry, certified by BAM, >99.5%
Sigma-Aldrich
HEPES, BioUltra, for molecular biology, ≥99.5% (T)
Sigma-Aldrich
Sodium chloride, AnhydroBeads, −10 mesh, 99.999% trace metals basis
Sigma-Aldrich
Sodium chloride solution, BioUltra, for molecular biology, ~5 M in H2O
Sigma-Aldrich
Propidium iodide, ≥94% (HPLC)
Sigma-Aldrich
Sodium chloride, BioUltra, for molecular biology, ≥99.5% (AT)
Sigma-Aldrich
Glycerol solution, 83.5-89.5% (T)
Sigma-Aldrich
Sodium chloride, tested according to Ph. Eur.
Sigma-Aldrich
Sodium chloride-35Cl, 99 atom % 35Cl
Sigma-Aldrich
Sodium chloride, random crystals, optical grade, 99.9% trace metals basis
Sigma-Aldrich
Sodium chloride solution, 0.85%
Sigma-Aldrich
Sodium chloride solution, 0.1 M
Sigma-Aldrich
Sodium chloride, JIS special grade, ≥99.5%
Sigma-Aldrich
Sodium chloride, SAJ first grade, ≥99.0%
Sigma-Aldrich
Sodium chloride solution, 1 M
Sigma-Aldrich
Glycerol solution, puriss., meets analytical specification of Ph. Eur., BP, 84-88%
Sigma-Aldrich
Sodium chloride, BioReagent, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99%
Sigma-Aldrich
HEPES, BioXtra, suitable for mouse embryo cell culture, ≥99.5% (titration)
Sigma-Aldrich
HEPES, BioPerformance Certified, ≥99.5% (titration), suitable for cell culture
Sigma-Aldrich
Sodium chloride, for molecular biology, DNase, RNase, and protease, none detected, ≥99% (titration)
Sigma-Aldrich
Propidium iodide, ≥94.0% (HPLC)
Sigma-Aldrich
Sodium chloride, BioXtra, ≥99.5% (AT)
Sigma-Aldrich
HEPES, BioXtra, pH 5.0-6.5 (1 M in H2O), ≥99.5% (titration)
Sigma-Aldrich
Sodium chloride, tablet
Sigma-Aldrich
Sodium chloride solution, 0.9% in water, BioXtra, suitable for cell culture
Sigma-Aldrich
Sodium chloride, meets analytical specification of Ph. Eur., BP, USP, 99.0-100.5%
Sigma-Aldrich
Sodium chloride solution, 5 M
Sigma-Aldrich
Sodium chloride solution, 5 M in H2O, BioReagent, for molecular biology, suitable for cell culture