PHOSPHOCHROMATOME ANALYSIS UNCOVERS UNEXPECTED ROLES OF CDK6 IN REGULATING TRANSCRIPTION
Author(s): ,
Sofie Nebenfuehr
Affiliations:
Department for Biomedical Science,Institute of Pharmacology and Toxicology, University of Veterinary Medicine,Vienna,Austria
,
Florian Bellutti
Affiliations:
Department for Biomedical Science,Institute of Pharmacology and Toxicology, University of Veterinary Medicine,Vienna,Austria
,
Karoline Kollmann
Affiliations:
Department for Biomedical Science,Institute of Pharmacology and Toxicology, University of Veterinary Medicine,Vienna,Austria
,
Matthias Farlik
Affiliations:
CeMM, Research Center for Molecular Medicine of the Austrian Academy of Science,Vienna,Austria
,
André C. Müller
Affiliations:
CeMM, Research Center for Molecular Medicine of the Austrian Academy of Science,Vienna,Austria
Veronika Sexl
Affiliations:
Department for Biomedical Science,Institute of Pharmacology and Toxicology, University of Veterinary Medicine,Vienna,Austria
EHA Library. Nebenfuehr S. Jun 15, 2019; 267228; PS927
Sofie Nebenfuehr
Sofie Nebenfuehr
Contributions
×
Abstract

Abstract: PS927

Type: Poster Presentation

Presentation during EHA24: On Saturday, June 15, 2019 from 17:30 - 19:00

Location: Poster area

Background

Cyclin-dependent kinase 6 (CDK6) together with its close homologue CDK4 enables the progression of cells through the early G1 phase of the cell cycle. CDK4/6-cyclin D complexes phosphorylate members of the retinoblastoma (Rb) protein family, allowing for the release of E2F transcription factors that induce genes required for cell cycle progression and DNA replication. Alterations of the CDK4/6-Rb pathway are frequently observed in human malignancies. Recent studies focusing on acute lymphoid leukemia (ALL) and acute myeloid leukemia (AML) have uncovered a novel role for CDK6 in regulating transcription. Our group has identified CDK6 as part of chromatin-bound complexes which drive transcription of disease–relevant genes including the cell cycle inhibitor p16INK4a, the angiogenesis-promoting factor VEGF-A (vascular endothelial factor A) and the proto-oncogene FLT3 (Fms like tyrosine kinase 3).

Aims

The aim of this study is to identify novel binding partners of CDK6 on chromatin and to investigate their target gene sets. A better understanding of CDK6 functionality in tumor formation and promotion may help in the design and selection of adequate treatment options.

Methods

For further investigation of CDK6´s role in transcription, we transduced murine Cdk6+/+ and Cdk6-/- primary bone marrow with the oncogene Bcr/Ablp185. To systematically gain insights on how CDK6 takes influence on chromatin-binding and activity of transcription factors we performed RNA-seq paralleled by mass spectrometry-based phosphoproteomics of chromatin-bound proteins (Phospho-Chromatome).

Results

RNA-seq analysis of Cdk6+/+ and Cdk6-/- BCR-ABL transformed cells identified more than 1700 genes that are differentially expressed. Phospho-Chromatome studies performed in parallel revealed significant changes in the phosphorylation status of the transcription factors ZBTB7A, EBF1 and YY1. In vitro kinase assays verified a direct phosphorylation of ZBTB7A and EBF1 by active CDK6/CyclinD3 complexes.

Conclusion

We show that CDK6 is broadly associated with chromatin where it fulfils different tasks: beside its well-known role in the E2F-release it enhances the phosphorylation of various transcription factors and chromatin-regulating enzymes. This results in pronounced changes in associated gene expression. Therefor our data indicate that the function of CDK6 is not limited to cell cycle progression but regulates a plethora of tumor-relevant transcriptional programs. Future therapies may consider this unexpected role and even exploit it to improve personalized and cancer-specific treatment protocols.

Session topic: 1. Acute lymphoblastic leukemia - Biology & Translational Research

Keyword(s): Cell cycle progression, Lymphoid malignancy, Transcriptional regulation

By continuing to browse or by clicking “Accept Terms & all Cookies”, you agree to the storing of third-party cookies on your device to enhance your user experience and agree to the user terms and conditions of this learning management system (LMS).

Cookie Settings
Accept Terms & all Cookies