| First Author | Vekariya U | Year | 2023 |
| Journal | Blood | Volume | 141 |
| Issue | 19 | Pages | 2372-2389 |
| PubMed ID | 36580665 | Mgi Jnum | J:337724 |
| Mgi Id | MGI:7496147 | Doi | 10.1182/blood.2022018428 |
| Citation | Vekariya U, et al. (2023) DNA polymerase theta protects leukemia cells from metabolically induced DNA damage. Blood 141(19):2372-2389 |
| abstractText | Leukemia cells accumulate DNA damage, but altered DNA repair mechanisms protect them from apoptosis. We showed here that formaldehyde generated by serine/1-carbon cycle metabolism contributed to the accumulation of toxic DNA-protein crosslinks (DPCs) in leukemia cells, especially in driver clones harboring oncogenic tyrosine kinases (OTKs: FLT3(internal tandem duplication [ITD]), JAK2(V617F), BCR-ABL1). To counteract this effect, OTKs enhanced the expression of DNA polymerase theta (POLtheta) via ERK1/2 serine/threonine kinase-dependent inhibition of c-CBL E3 ligase-mediated ubiquitination of POLtheta and its proteasomal degradation. Overexpression of POLtheta in OTK-positive cells resulted in the efficient repair of DPC-containing DNA double-strand breaks by POLtheta-mediated end-joining. The transforming activities of OTKs and other leukemia-inducing oncogenes, especially of those causing the inhibition of BRCA1/2-mediated homologous recombination with and without concomitant inhibition of DNA-PK-dependent nonhomologous end-joining, was abrogated in Polq-/- murine bone marrow cells. Genetic and pharmacological targeting of POLtheta polymerase and helicase activities revealed that both activities are promising targets in leukemia cells. Moreover, OTK inhibitors or DPC-inducing drug etoposide enhanced the antileukemia effect of POLtheta inhibitor in vitro and in vivo. In conclusion, we demonstrated that POLtheta plays an essential role in protecting leukemia cells from metabolically induced toxic DNA lesions triggered by formaldehyde, and it can be targeted to achieve a therapeutic effect. |
