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Cullinane, C.

Publications and source records attributed to Cullinane, C..

2 recordsLinked to original sources

RNA binding kinase UHMK1 regulates therapy induced metabolic adaptation in BRAFV600 melanoma

Despite the success of therapies targeting oncogenes in cancer, clinical outcomes are limited by a residual disease that results in relapse. This residual disease is characterized by drug-induced adaptation, that in melanoma includes altered metabolism. Here, we examined how targeted therapy reprograms metabolism in BRAF-mutant melanoma cells using a genome-wide RNAi screen and global gene expression profiling. This systematic approach revealed post-transcriptional regulation of metabolism following BRAF inhibition, involving selective mRNA transport and translation. As proof of concept we demonstrate the RNA binding kinase UHMK1 interacts with mRNAs that encode metabolic proteins and selectively controls their transport and translation during adaptation to BRAF targeted therapy. Inactivation of UHMK1 improves metabolic response to BRAF targeted therapy and delays resistance to BRAF and MEK combination therapy in vivo. Our data support a model wherein post-transcriptional gene expression pathways regulate metabolic adaptation underpinning targeted therapy response and suggest inactivation of these pathways may delay disease relapse.

cancer biology

Inhibition of RNA Polymerase I Transcription Activates Targeted DNA Damage Response and Enhances the Efficacy of PARP Inhibitors in High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) accounts for the majority of ovarian cancer and has a dismal prognosis. PARP inhibitors (PARPi) have revolutionized disease management of patients with homologous recombination (HR) DNA repair-deficient HGSOC. However, acquired resistance to PARPi by complex mechanisms including HR restoration and stabilisation of replication forks is a major challenge in the clinic. Here, we demonstrate CX-5461, an inhibitor of RNA polymerase I transcription of ribosomal RNA genes (rDNA), induces replication stress at rDNA leading to activation of DNA damage response and DNA damage involving MRE11-dependent degradation of replication forks. CX-5461 cooperates with PARPi in exacerbating DNA damage and enhances synthetic lethal interactions of PARPi with HR deficiency in HGSOC-patient-derived xenograft (PDX) in vivo. We demonstrate CX-5461 has a different sensitivity spectrum to PARPi and destabilises replication forks irrespective of HR pathway status, overcoming two well-known mechanisms of resistance to PARPi. Importantly, CX-5461 exhibits single agent efficacy in PARPi-resistant HGSOC-PDX. Further, we identify CX-5461-sensitivity gene expression signatures in primary and relapsed HGSOC. Therefore, CX-5461 is a promising therapy alone and in combination therapy with PARPi in HR-deficient HGSOC. CX-5461 is also an exciting treatment option for patients with relapsed HGSOC tumors that have poor clinical outcome.

cancer biology