Lung cancer is the leading cause of cancer deaths, and effective treatments are urgently needed. Loss-of-function mutations in the DNA damage response kinase ATM are common in lung adenocarcinoma but directly targeting these with drugs remains challenging. Here we report that ATM loss-of-function is synthetic lethal with drugs inhibiting the central growth factor kinases MEK1/2, including the FDA-approved drug trametinib. Lung cancer cells resistant to MEK inhibition become highly sensitive upon loss of ATM both in vitro and in vivo. Mechanistically, ATM mediates crosstalk between the prosurvival MEK/ERK and AKT/mTOR pathways. ATM loss also enhances the sensitivity of KRAS- or BRAF-mutant lung cancer cells to MEK inhibition. Thus, ATM mutational status in lung cancer is a mechanistic biomarker for MEK inhibitor response, which may improve patient stratification and extend the applicability of these drugs beyond RAS and BRAF mutant tumours.

• MeSH
• ATM protein genetika   metabolismus   MeSH
• benzamidy farmakologie   MeSH
• difenylamin analogy a deriváty   farmakologie   MeSH
• inhibitory proteinkinas farmakologie   MeSH
• lidé MeSH
• močovina analogy a deriváty   farmakologie   MeSH
• mutace * MeSH
• myši nahé MeSH
• nádorové buněčné linie MeSH
• nádory plic genetika   metabolismus   prevence a kontrola   MeSH
• proliferace buněk účinky léků   genetika   MeSH
• protoonkogenní proteiny B-Raf genetika   metabolismus   MeSH
• pyridony farmakologie   MeSH
• pyrimidinony farmakologie   MeSH
• Ras proteiny genetika   metabolismus   MeSH
• RNA interference MeSH
• thiofeny farmakologie   MeSH
• xenogenní modely - testy antitumorózní aktivity MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 3-(carbamoylamino)-5-(3-fluorophenyl)-N-(3-piperidyl)thiophene-2-carboxamide MeSH Prohlížeč
• ATM protein MeSH
• benzamidy MeSH
• BRAF protein, human MeSH Prohlížeč
• difenylamin MeSH
• inhibitory proteinkinas MeSH
• mirdametinib MeSH Prohlížeč
• močovina MeSH
• protoonkogenní proteiny B-Raf MeSH
• pyridony MeSH
• pyrimidinony MeSH
• Ras proteiny MeSH
• thiofeny MeSH
• trametinib MeSH Prohlížeč

Based on a series of basic, preclinical and clinical studies, the Poly (ADP-ribose) Polymerase 1 (PARP1) inhibitor, olaparib, has recently been approved for use in ovarian cancer patients with BRCA1 or BRCA2 mutations. By identifying novel predictive biomarkers of tumour cell sensitivity to olaparib, it is possible that the utility of PARP inhibitors could be extended beyond this patient subgroup. Many of the known genetic determinants of PARP inhibitor response have key roles in DNA damage response (DDR) pathways. Although protein ubiquitylation is known to play an important role in regulating the DDR, the exact mechanisms by which this occurs are not fully understood. Using two parallel RNA interference-based screening approaches, we identified the E3 ubiquitin ligase, CBLC, as a candidate biomarker of response to olaparib. We validated this observation by demonstrating that silencing of CBLC causes increased sensitivity to olaparib in breast cancer cell line models and that defective homologous recombination (HR) DNA repair is the likely cause. This data provides an example of how defects in the ubiquitin machinery have the potential to influence the response of tumour cells to PARP inhibitors.

• Klíčová slova
• CBLC, DNA damage response, PARP inhibitors, RNA interference screens, ubiquitin-proteasome system,
• MeSH
• časové faktory MeSH
• ftalaziny farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory prsu farmakoterapie   enzymologie   genetika   patologie   MeSH
• oprava DNA MeSH
• PARP inhibitory farmakologie   MeSH
• piperaziny farmakologie   MeSH
• poly-ADP-ribóza-polymeráza 1 MeSH
• poly(ADP-ribosa)-polymerasy genetika   metabolismus   MeSH
• posttranslační úpravy proteinů MeSH
• protein BRCA2 genetika   metabolismus   MeSH
• protoonkogenní proteiny c-cbl genetika   metabolismus   MeSH
• regulace genové exprese u nádorů MeSH
• rekombinace genetická MeSH
• RNA interference MeSH
• signální transdukce účinky léků   MeSH
• transfekce MeSH
• ubikvitinace MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• BRCA2 protein, human MeSH Prohlížeč
• CBLC protein, human MeSH Prohlížeč
• ftalaziny MeSH
• olaparib MeSH Prohlížeč
• PARP inhibitory MeSH
• PARP1 protein, human MeSH Prohlížeč
• piperaziny MeSH
• poly-ADP-ribóza-polymeráza 1 MeSH
• poly(ADP-ribosa)-polymerasy MeSH
• protein BRCA2 MeSH
• protoonkogenní proteiny c-cbl MeSH

The Cdk12/CycK complex promotes expression of a subset of RNA polymerase II genes, including those of the DNA damage response. CDK12 is among only nine genes with recurrent somatic mutations in high-grade serous ovarian carcinoma. However, the influence of these mutations on the Cdk12/CycK complex and their link to cancerogenesis remain ill-defined. Here, we show that most mutations prevent formation of the Cdk12/CycK complex, rendering the kinase inactive. By examining the mutations within the Cdk12/CycK structure, we find that they likely provoke structural rearrangements detrimental to Cdk12 activation. Our mRNA expression analysis of the patient samples containing the CDK12 mutations reveals coordinated downregulation of genes critical to the homologous recombination DNA repair pathway. Moreover, we establish that the Cdk12/CycK complex occupies these genes and promotes phosphorylation of RNA polymerase II at Ser2. Accordingly, we demonstrate that the mutant Cdk12 proteins fail to stimulate the faithful DNA double strand break repair via homologous recombination. Together, we provide the molecular basis of how mutated CDK12 ceases to function in ovarian carcinoma. We propose that CDK12 is a tumor suppressor of which the loss-of-function mutations may elicit defects in multiple DNA repair pathways, leading to genomic instability underlying the genesis of the cancer.

• MeSH
• cyklin-dependentní kinasy chemie   genetika   metabolismus   MeSH
• cykliny chemie   genetika   metabolismus   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• multiproteinové komplexy genetika   metabolismus   MeSH
• mutace * MeSH
• nádorové buněčné linie MeSH
• nádory vaječníků genetika   metabolismus   patologie   MeSH
• oprava DNA genetika   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• regulace genové exprese u nádorů MeSH
• RNA interference MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• terciární struktura proteinů MeSH
• vazba proteinů MeSH
• western blotting MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CCNK protein, human MeSH Prohlížeč
• CDK12 protein, human MeSH Prohlížeč
• cyklin-dependentní kinasy MeSH
• cykliny MeSH
• multiproteinové komplexy MeSH