Selective CDK9 inhibition overcomes TRAIL resistance by concomitant suppression of cFlip and Mcl-1.
Cell Death Differ
; 21(3): 491-502, 2014 Mar.
Article
en En
| MEDLINE
| ID: mdl-24362439
ABSTRACT
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in many cancer cells without causing toxicity in vivo. However, to date, TRAIL-receptor agonists have only shown limited therapeutic benefit in clinical trials. This can, most likely, be attributed to the fact that 50% of all cancer cell lines and most primary human cancers are TRAIL resistant. Consequently, future TRAIL-based therapies will require the addition of sensitizing agents that remove crucial blocks in the TRAIL apoptosis pathway. Here, we identify PIK-75, a small molecule inhibitor of the p110α isoform of phosphoinositide-3 kinase (PI3K), as an exceptionally potent TRAIL apoptosis sensitizer. Surprisingly, PI3K inhibition was not responsible for this activity. A kinome-wide in vitro screen revealed that PIK-75 strongly inhibits a panel of 27 kinases in addition to p110α. Within this panel, we identified cyclin-dependent kinase 9 (CDK9) as responsible for TRAIL resistance of cancer cells. Combination of CDK9 inhibition with TRAIL effectively induced apoptosis even in highly TRAIL-resistant cancer cells. Mechanistically, CDK9 inhibition resulted in downregulation of cellular FLICE-like inhibitory protein (cFlip) and Mcl-1 at both the mRNA and protein levels. Concomitant cFlip and Mcl-1 downregulation was required and sufficient for TRAIL sensitization by CDK9 inhibition. When evaluating cancer selectivity of TRAIL combined with SNS-032, the most selective and clinically used inhibitor of CDK9, we found that a panel of mostly TRAIL-resistant non-small cell lung cancer cell lines was readily killed, even at low concentrations of TRAIL. Primary human hepatocytes did not succumb to the same treatment regime, defining a therapeutic window. Importantly, TRAIL in combination with SNS-032 eradicated established, orthotopic lung cancer xenografts in vivo. Based on the high potency of CDK9 inhibition as a cancer cell-selective TRAIL-sensitizing strategy, we envisage the development of new, highly effective cancer therapies.
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Quinasa 9 Dependiente de la Ciclina
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Ligando Inductor de Apoptosis Relacionado con TNF
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Proteína Reguladora de Apoptosis Similar a CASP8 y FADD
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Proteína 1 de la Secuencia de Leucemia de Células Mieloides
Tipo de estudio:
Clinical_trials
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Prognostic_studies
Límite:
Animals
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Female
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Humans
Idioma:
En
Revista:
Cell Death Differ
Año:
2014
Tipo del documento:
Article
País de afiliación:
Alemania