Proline tRNA biogenesis as oncogenic drivers and therapeutic target in T cell acute lymphoblastic leukemia

Proline tRNA biogenesis as oncogenic drivers and therapeutic target in T cell acute lymphoblastic leukemia Although transfer RNAs (tRNAs) have emerged as dynamic and significant regulators of cancer progression, a critical gap in knowledge still remains in defining the mechanisms linking tRNA deregulation to tumor pathogenesis and therapy resistance. The long-term goal is to define the role of tRNA deregulation in the biology of cancers with T cell acute lymphoblastic leukemia (T-ALL) as a disease model. Preliminary studies highlight that upregulated proline tRNA biogenesis contributes to T-ALL proliferation and viability. Specifically, expression of the bifunctional glutamyl-prolyl-tRNA synthetase (EPRS1) and tRNA-Pro isoacceptors (tRNAs with different anticodons but carry the same amino acid) is significantly upregulated in primary T-ALL samples relative to thymocytes and mature T cell subsets from healthy individuals. Pharmacological inhibiton of the prolyl tRNA synthetase (ProRS) activity of EPRS1, which aminoacylates proline tRNA isoacceptors with the cognate amino acid proline, induced cell death in T-ALL in vitro compared to T cells from healthy donors. Global proteomic analysis following ProRS inhibition identified singnificant decrease in the expression levels of proline rich oncogenic proteins, highlighting deregulated proline tRNA biogenesis as a critical adaptation in the establishment of oncogenic gene expression programs in T-ALL. The overall objectives in this application are (i) to determine the molecular mechanisms by which upregulated proline tRNA biogenesis promote oncogenic gene expression programs in T-ALL and (ii) determine the oncogenic role of this pathway in vivo. The rationale for this project is that mechanistic understanding of the role of proline tRNA biogenesis in T-ALL pathogenesis will provide a strong scientific framework to develop new cancer therapeutics targeting tRNA. The central hypothesis is that upregulated proline tRNA biogenesis is critical for initiation and progression of T-ALL. This central hypothesis will be tested using two specific aims: 1) Mechanistic dissection of the role of upregulated proline tRNA biogenesis in T-ALL and 2) Define the role EPRS1 in T-ALL initiation and progression using genetic murine models. In the first aim, proline tRNA biogenesis will be perturbed using orthogonal approaches in vitro (ProRS inhibition and CRISPRi silencing of tRNA-Pro genes) in cell line models and profiled using tRNA-Seq (RNA-seq), ribosome density profiling (Ribo-Seq) and total RNA-seq to identify changes in mRNA translation sensitive to proline tRNA expression and aminoacylation levels at single codon resolution. For the second aim, genetic murine models will be used to conditionally delete Eprs1 to test the effects of loss of Eprs1 in T-ALL initiation and progression. The research proposed in this application is innovative, because it explores previously overlooked roles of leukemic cell-intrinsic tRNA dysregulation in the development of T-ALL. Relapsed/refractory T-ALL with dismal prognosis remains a clinical urgency. The proposed research is significant because it paves the way for the development of novel cancer therapeutics focused on targeting tRNA regulatory pathways downstream of oncogenic activation in T-ALL and likely other cancers. Project Number: 1R37CA307194-01 | Fiscal Year: 2026 | NIH Institute/Center: National Cancer Institute (NCI) | Principal Investigator: Palaniraja Thandapani | Institution: UNIVERSITY OF TX MD ANDERSON CAN CTR, HOUSTON, TX | Award Amount: $473,372 | Activity Code: R37 | Study Section: Gene Regulation in Cancer Study Section[GRIC] View on NIH RePORTER: https://reporter.nih.gov/project-details/11271113