ABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
The post-genomic era has seen many advances in our understanding of cancer pathways, yet resistance and tumor heterogeneity necessitate multiple approaches to target even monogenic tumors. Here, we combine phenotypic screening with chemical genetics to identify pre-messenger RNA endonuclease cleavage and polyadenylation specificity factor 3 (CPSF3) as the target of JTE-607, a small molecule with previously unknown target. We show that CPSF3 represents a synthetic lethal node in a subset of acute myeloid leukemia (AML) and Ewing's sarcoma cancer cell lines. Inhibition of CPSF3 by JTE-607 alters expression of known downstream effectors in AML and Ewing's sarcoma lines, upregulates apoptosis and causes tumor-selective stasis in mouse xenografts. Mechanistically, it prevents the release of newly synthesized pre-mRNAs, resulting in read-through transcription and the formation of DNA-RNA hybrid R-loop structures. This study implicates pre-mRNA processing, and specifically CPSF3, as a druggable target providing an avenue to therapeutic intervention in cancer.
Subject(s)
Cleavage And Polyadenylation Specificity Factor/metabolism , Leukemia, Myeloid, Acute/metabolism , RNA Precursors/metabolism , Sarcoma, Ewing/metabolism , Animals , Apoptosis/drug effects , Binding Sites , Carboxylic Ester Hydrolases/metabolism , Cell Line, Tumor , Cell Survival , Cleavage And Polyadenylation Specificity Factor/genetics , HEK293 Cells , Humans , Leukemia, Myeloid, Acute/drug therapy , Male , Mass Spectrometry , Mice , Mice, Inbred C57BL , Neoplasm Transplantation , Phenotype , Phenylalanine/analogs & derivatives , Phenylalanine/pharmacology , Piperazines/pharmacology , Protein Binding , RNA, Messenger/metabolism , RNA, Small Interfering/metabolism , Sarcoma, Ewing/drug therapyABSTRACT
The hormone αKlotho regulates lifespan in mice, as knockouts die early of what appears to be accelerated aging due to hyperphosphatemia and soft tissue calcification. In contrast, the overexpression of αKlotho increases lifespan. Given the severe mouse phenotype, we generated zebrafish mutants for αklotho as well as its binding partner fibroblast growth factor-23 (fgf23). Both mutations cause shortened lifespan in zebrafish, with abrupt onset of behavioral and degenerative physical changes at around 5 months of age. There is a calcification of vessels throughout the body, most dramatically in the outflow tract of the heart, the bulbus arteriosus (BA). This calcification is associated with an ectopic activation of osteoclast differentiation pathways. These findings suggest that the gradual loss of αKlotho found in normal aging might give rise to ectopic calcification.
