Mechanistic study of histone acyltransferase HBO1 in regulating ZAP to promote nasopharyngeal carcinoma progression

Nasopharyngeal carcinoma (NPC) is a malignant neoplasm arising from the nasopharyngeal epithelium, with a particularly high incidence in southern China and Singapore. HBO1 (Histone Acetyltransferase Binding to ORC1), a multifunctional acyltransferase, has been implicated in the initiation and progression of diverse human malignancies. To date, current investigations into its oncogenic mechanisms have been predominantly confined to its role in regulating histone acetylation, leaving other potential pathways underexplored.

In the present study, we performed qPCR assay, western blotting (WB) assay, and immunohistochemical analyses and observed markedly elevated HBO1 mRNA and protein expression in multiple NPC cell lines and clinical biopsy specimens. Using ectopic overexpression of HBO1, CRISPR-Cas9 knockout, shRNA knockdown or WM-3835 (a specific HBO1 inhibitor ) treatment strategies in C666-1 and CNE2 cells—two extensively validated models of NPC—we demonstrated that inhibition or overexpression of HBO1 could correspondingly suppress or accelerate malignant phenotypes, as evidenced by CCK-8 proliferation assays, colony formation assay, EdU assays, wound-healing assay, and transwell migration/invasion assays. Flow-cytometric cell-cycle and annexin V-based apoptosis analyses, together with WB assay, revealed that HBO1 inhibition could provoke G0/G1-phase arrest and caspase-dependent apoptosis. Transcriptomic profiling by high-throughput RNA-Seq and subsequent pathway enrichment analyses identified zinc-finger antiviral protein (ZAP) and the NF-κB signaling cascade among the key downstream targets transcriptionally controlled by HBO1. Although ZAP has been characterized primarily as a broad-spectrum antiviral effector, its contribution to tumorigenesis remains largely unexplored. We observed that depletion of ZAP markedly attenuated NPC cell proliferation and attenuated the expression of multiple pro-inflammatory cytokines. ChIP-qPCR assay demonstrated that HBO1 could occupy the ZAP promoter and directly regulate its transcription. Co-IP and reciprocal pulldown experiments further revealed a physical interaction between HBO1 and ZAP. Additionally, HBO1 could modulate the acetylation levels of ZAP.

Collectively, these findings support a novel paradigm in which HBO1 drives NPC progression through transcriptional and post-translational control of ZAP. This work not only expands the mechanistic understanding of NPC pathogenesis but also provides a rational foundation for the development of HBO1/ZAP-targeted anti-NPC therapeutic strategies.

Dr. Yu Liu, with a PhD from Wuhan University and a one-year exchange at Temple University, has solid expertise in tumor immunotherapy and anti-pathogen infection. She has published 7 SCI articles as the first/corresponding author, and has over 4 years experience in R&D of antibody drugs and CAR-T cell drugs at WuXi Biologics and Wuhan Bio-Raid Biotechnology Co., Ltd. This has enabled her to accumulate rich experience ranging from basic research to industrial transformation. She is currently a lecturer of the College of Life Sciences and Health at Wuhan University of Science and Technology.