Genomic characterization of host gene alterations in Theileria annulata-transformed leukocytes.

Theileria annulata-infected host leukocytes exhibit cancer-like phenotypes, driven by mechanisms that remain incompletely understood. This study explores the genomic alterations underlying these transformations using whole-genome sequencing and bioinformatic analyses of six clinically relevant T. annulata-infected cell lines. Here we identify 7867 exon-linked somatic mutations shared across all cell lines, with significant enrichment in oncogenes (e.g., FLT4, NOTCH2, MAP3K1, DAXX, FCGR2B, ROS1) and tumor suppressor genes (e.g., BARD1, KMT2C, GRIN2A, BAP1). These mutations are associated with critical cancer-related pathways. Functional studies revealed that inhibition of the mutated oncogene ROS1 using crizotinib induces death in infected leukocytes, confirming its role in transformation. Additionally, we observe mutations in genes linked to genomic instability and the DNA damage response (DDR) pathways, highlighting potential parallels with cancer biology. Suppression of TP53, a key tumor suppressor, is implicated in the immortalization of infected cells, while upregulation of the DNA mutator enzyme APOBEC3H suggests a parasite-driven, mutation-inducing mechanism. Our findings provide new insights into how T. annulata reprograms host cells through genomic instability and mutations, identifying ROS1 and TP53 as critical targets for therapeutic intervention. This work advances understanding of parasite-induced oncogenic transformation and offers pathways for future research.