Dataset Information

Dabrafenib inhibits the growth of BRAF-WT cancers through CDK16 and NEK9 inhibition.

ABSTRACT: Although the BRAF inhibitors dabrafenib and vemurafenib have both proven successful against BRAF-mutant melanoma, there seem to be differences in their mechanisms of action. Here, we show that dabrafenib is more effective at inhibiting the growth of NRAS-mutant and KRAS-mutant cancer cell lines than vemurafenib. Using mass spectrometry-based chemical proteomics, we identified NEK9 and CDK16 as unique targets of dabrafenib. Both NEK9 and CDK16 were highly expressed in specimens of advanced melanoma, with high expression of both proteins correlating with a worse overall survival. A role for NEK9 in the growth of NRAS- and KRAS-mutant cell lines was suggested by siRNA studies in which silencing was associated with decreased proliferation, cell cycle arrest associated with increased p21 expression, inhibition of phospho-CHK1, decreased CDK4 expression, and the initiation of a senescence response. Inhibition of CDK4 but not CHK1 recapitulated the effects of NEK9 silencing, indicating this to be the likely mechanism of growth inhibition. We next turned our attention to CDK16 and found that its knockdown inhibited the phosphorylation of the Rb protein at S780 and increased expression of p27. Both of these effects were phenocopied in NRAS- and KRAS-mutant cancer cells by dabrafenib, but not vemurafenib. Combined silencing of NEK9 and CDK16 was associated with enhanced inhibition of melanoma cell proliferation. In summary, we have identified dabrafenib as a potent inhibitor of NEK9 and CDK16, and our studies suggest that inhibition of these kinases may have activity against cancers that do not harbor BRAF mutations.

SUBMITTER: Phadke M

PROVIDER: S-EPMC5748485 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

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Dabrafenib inhibits the growth of BRAF-WT cancers through CDK16 and NEK9 inhibition.

Phadke Manali M Remsing Rix Lily L LL Smalley Inna I Bryant Annamarie T AT Luo Yunting Y Lawrence Harshani R HR Schaible Braydon J BJ Chen Yian A YA Rix Uwe U Smalley Keiran S M KSM

Molecular oncology 20171123 1

Although the BRAF inhibitors dabrafenib and vemurafenib have both proven successful against BRAF-mutant melanoma, there seem to be differences in their mechanisms of action. Here, we show that dabrafenib is more effective at inhibiting the growth of NRAS-mutant and KRAS-mutant cancer cell lines than vemurafenib. Using mass spectrometry-based chemical proteomics, we identified NEK9 and CDK16 as unique targets of dabrafenib. Both NEK9 and CDK16 were highly expressed in specimens of advanced melano ...[more]

PMID: 29112787

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Project description:On June 22, 2017, the Food and Drug Administration expanded indications for dabrafenib and trametinib to include treatment of patients with metastatic non-small cell lung cancer (NSCLC) harboring BRAF V600E mutations. Approval was based on results from an international, multicenter, multicohort, noncomparative, open-label trial, study BRF113928, which sequentially enrolled 93 patients who had received previous systemic treatment for advanced NSCLC (Cohort B, n?=?57) or were treatment-naïve (Cohort C, n?=?36). All patients received dabrafenib 150 mg orally twice daily and trametinib 2 mg orally once daily. In Cohort B, overall response rate (ORR) was 63% (95% confidence interval [CI] 49%-76%) with response durations ?6 months in 64% of responders. In Cohort C, ORR was 61% (95% CI 44%-77%) with response durations ?6 months in 59% of responders. Results were evaluated in the context of the Intergroupe Francophone de Cancérologie Thoracique registry and a chart review of U.S. electronic health records at two academic sites, characterizing treatment outcomes data for patients with metastatic NSCLC with or without BRAF V600E mutations. The treatment effect of dabrafenib 150 mg twice daily was evaluated in 78 patients with previously treated BRAF mutant NSCLC, yielding an ORR of 27% (95% CI 18%-38%), establishing that dabrafenib alone is active, but that the addition of trametinib is necessary to achieve an ORR of >40%. The most common adverse reactions (?20%) were pyrexia, fatigue, nausea, vomiting, diarrhea, dry skin, decreased appetite, edema, rash, chills, hemorrhage, cough, and dyspnea. IMPLICATIONS FOR PRACTICE:The approvals of dabrafenib and trametinib, administered concurrently, provide a new regimen for the treatment of a rare subset of non-small cell lung cancer (NSCLC) and demonstrate how drugs active for treatment of BRAF-mutant tumors in one setting predict efficacy and can provide supportive evidence for approval in another setting. The FDA also approved the first next-generation sequencing oncology panel test for simultaneous assessment of multiple actionable mutations, which will facilitate selection of optimal, personalized therapy. The test was shown to accurately and reliably select patients with NSCLC with the BRAF V600E mutation for whom treatment with dabrafenib and trametinib is the optimal treatment.

Dataset Information

Dabrafenib inhibits the growth of BRAF-WT cancers through CDK16 and NEK9 inhibition.

Publications

Dabrafenib inhibits the growth of BRAF-WT cancers through CDK16 and NEK9 inhibition.

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