Efficacy of CDK4 inhibition against sarcomas depends on their levels of CDK4 and p16ink4 mRNA.

Oncotarget 2015 Dec;6(38):40557-74

Instituto de Biomedicina de Sevilla, IBIS/Hospital Universitario Virgen del Rocio/Universidad de Sevilla/Consejo Superior de Investigaciones Cientificas, Seville, Spain.

Sarcomas are malignant tumors accounting for a high percentage of cancer morbidity and mortality in children and young adults. Surgery and radiation therapy are the accepted treatments for most sarcomas; however, patients with metastatic disease are treated with systemic chemotherapy. Many tumors display marginal levels of chemoresponsiveness and new treatment approaches are needed. Deregulation of the G1 checkpoint is crucial for various oncogenic transformation processes, suggesting that many cancer cell types depend on CDK4/6 activity. Thus, CDK4/6 activity appears to represent a promising therapeutic target for cancer treatment. In the present work, we explore the efficacy of CDK4 inhibition using palbociclib (PD0332991), a highly selective inhibitor of CDK4/6, in a panel of sarcoma cell lines and sarcoma tumor xenografts (PDXs). Palbociclib induces senescence in these cell lines and the responsiveness of these cell lines correlated with their levels of CDK4 mRNA. Palbociclib is also active in vivo against sarcomas displaying high levels of CDK4 but not against sarcomas displaying low levels of CDK4 and high levels of p16ink4a. The analysis of tumors growing after palbociclib showed a clear decrease in the CDK4 levels, indicating that clonal selection occurred in these treated tumors. In summary, our data support the efficacy of CDK4 inhibitors against sarcomas displaying increased CDK4 levels, particularly fibrosarcomas and MPNST. Our results also suggest that high levels of p16ink4a may indicate poor efficacy of CDK4 inhibitors.

Download full-text PDF

Source
http://dx.doi.org/10.18632/oncotarget.5829DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4747352PMC
December 2015
18 Reads

Publication Analysis

Top Keywords

levels cdk4
16
efficacy cdk4
16
cell lines
12
sarcomas displaying
12
high levels
12
cdk4
9
levels
9
cdk4 levels
8
levels p16ink4a
8
cdk4/6 activity
8
cdk4 inhibition
8
cdk4 inhibitors
8
sarcomas
6
sarcoma cell
4
cdk4/6 panel
4
highly selective
4
selective inhibitor
4
inhibitor cdk4/6
4
panel sarcoma
4
tumor xenografts
4

Similar Publications