Orally bioavailable CDK9/2 inhibitor shows mechanism-based therapeutic potential in MYCN-driven neuroblastoma.

Abstract

The undruggable nature of oncogenic Myc transcription factors poses a therapeutic challenge in neuroblastoma, a pediatric cancer in which MYCN amplification is strongly associated with unfavorable outcome. Here, we show that CYC065 (fadraciclib), a clinical inhibitor of CDK9 and CDK2, selectively targeted MYCN-amplified neuroblastoma via multiple mechanisms. CDK9 - a component of the transcription elongation complex P-TEFb - bound to the MYCN-amplicon superenhancer, and its inhibition resulted in selective loss of nascent MYCN transcription. MYCN loss led to growth arrest, sensitizing cells for apoptosis following CDK2 inhibition. In MYCN-amplified neuroblastoma, MYCN invaded active enhancers, driving a transcriptionally encoded adrenergic gene expression program that was selectively reversed by CYC065. MYCN overexpression in mesenchymal neuroblastoma was sufficient to induce adrenergic identity and sensitize cells to CYC065. CYC065, used together with temozolomide, a reference therapy for relapsed neuroblastoma, caused long-term suppression of neuroblastoma growth in vivo, highlighting the clinical potential of CDK9/2 inhibition in the treatment of MYCN-amplified neuroblastoma.

• Authors: Evon Poon, Tong Liang, Yann Jamin, Susanne Walz, Colin Kwok, Anne Hakkert, Karen Barker, Zuzanna Urban, Khin Thway, Rhamy Zeid, Albert Hallsworth, Gary Box, Marli E Ebus, Marco P Licciardello, Yordan Sbirkov, Glori Lazaro, Elizabeth Calton, Barbara M Costa, Melanie Valenti, Alexis De Haven Brandon, Hannah Webber, Nicolas Tardif, Gilberto S Almeida, Rossitza Christova, Gunther Boysen, Mark W Richards, Giuseppe Barone, Anthony Ford, Richard Bayliss, Paul A Clarke, Johann De Bono, Nathanael S Gray, Julian Blagg, Simon P Robinson, Suzanne A Eccles, Daniella Zheleva, James E Bradner, Jan Molenaar, Igor Vivanco, Martin Eilers, Paul Workman, Charles Y Lin, Louis Chesler
• Journal: The Journal of clinical investigation (J Clin Invest) Vol. 130 Issue 11 Pg. 5875-5892 (11 02 2020) ISSN: 1558-8238 [Electronic] United States
• PMID: 33016930 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• CYC065
• MYCN protein, human
• N-Myc Proto-Oncogene Protein
• Positive Transcriptional Elongation Factor B
• CDK2 protein, human
• CDK9 protein, human
• Cyclin-Dependent Kinase 2
• Cyclin-Dependent Kinase 9
• Adenosine
• Temozolomide

Topics

• Adenosine (analogs & derivatives, pharmacology)
• Cell Line, Tumor
• Cyclin-Dependent Kinase 2 (antagonists & inhibitors, metabolism)
• Cyclin-Dependent Kinase 9 (antagonists & inhibitors, metabolism)
• Enhancer Elements, Genetic
• Humans
• N-Myc Proto-Oncogene Protein (biosynthesis, genetics)
• Neuroblastoma (drug therapy, genetics, metabolism, pathology)
• Positive Transcriptional Elongation Factor B (genetics, metabolism)
• Temozolomide (pharmacology)
• Transcription, Genetic (drug effects)