PXD032188-1

PXD032188 is an original dataset announced via ProteomeXchange.

Title	Signalling Inhibition by Ponatinib Disrupts Productive Alternative Lengthening of Telomeres (ALT)
Description	Alternative lengthening of telomeres (ALT) supports telomere maintenance and replicative immortality in around 10-15% of cancers, thus representing a compelling target for therapy.To identify anti-cancer drugs that can be repurposed as ALT-centered therapies, we performed for a compound library screen on isogenic cell lines that rely either on telomerase or ALT mechanisms. We validated candidates on a panel of ALT- vs. telomerase-positive sarcoma cells and assessed levels of extrachromosomal telomeric C-circles after drug treatment, as a bona fide marker of ALT activity. We identified a receptor tyrosine kinase inhibitor ponatinib that deregulated ALT mechanisms, increased telomeric replicative stress and induced telomeric dysfunction in ALT cells. Using a model of ALT sarcoma xenografts, we found that ponatinib targeted ALT-positive cells and mitigated telomere elongation in these tumors. To identify the mode of action of ponatinib on ALT, we performed RNA-sequencing and quantitative proteomic and phosphoproteomic analyses, and shortlisted candidates to test the effect of their loss on telomeric C-circle levels. We identified an ABL1-JNK-JUN signalling circuit to be inhibited by ponatinib and to have a role in suppressing extrachromosomal telomeric C-circle formation. Furthermore, transcriptome and interactome analyses of JUN suggested a role of JUN in DNA damage repair pathways, independently of its capacity as a transcription factor. These results were corroborated by new synergistic drug interactions between ponatinib and either DNA synthesis or repair inhibitors such as triciribine and KU-60019, respectively. Overall, we identified a novel signalling pathway impacting ALT which can be targeted by a clinically approved kinase inhibitor.
HostingRepository	PRIDE
AnnounceDate	2022-03-14
AnnouncementXML	Submission_2022-03-14_04:49:37.836.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Dennis Kappei
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	phosphorylated residue
Instrument	Q Exactive HF

Revision	Datetime	Status	ChangeLog Entry
0	2022-03-10 14:31:25	ID requested
⏵ 1	2022-03-14 04:49:38	announced

Dataset with its publication pending

submitter keyword: Ponatinib, ALT, telomeres, singalling, phosphoproteomics, sarcoma

Dennis Kappei
contact affiliation	Cancer Science Institute of Singapore, National University of Singapore
contact email	dennis.kappei@nus.edu.sg
lab head
Dennis Kappei
contact affiliation	Cancer Science Institute of Singapore
contact email	dennis.kappei@nus.edu.sg
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD032188
     1. Label: PRIDE project
     2. Name: Signalling Inhibition by Ponatinib Disrupts Productive Alternative Lengthening of Telomeres (ALT)