Bortezomib Induces Apoptosis <i>via</i> Upregulation of Abhd4 in Peripheral Nerve Cells

Bortezomib, a first-in-class proteasome inhibitor, is widely used to treat multiple myeloma and other hematological malignancies. Despite its therapeutic efficacy, bortezomib causes peripheral neuropathy (PN) in approximately 20-30% of patients, often leading to dose reduction or discontinuation. Preventive or therapeutic approaches to bortezomib-induced PN are currently unavailable, as its precise mechanism remains unclear. In this study, we compared the effects of bortezomib and the second-generation proteasome inhibitor carfilzomib on peripheral nerve cells to identify candidate molecules involved in PN development. Transcriptome profiling of differentiated F11 cells, a hybridoma of a rat embryonic dorsal root ganglion and mouse neuroblastoma cell line N18TG2, revealed that bortezomib selectively upregulated α/β-hydrolase containing domain 4 (Abhd4), whereas carfilzomib did not. This finding was confirmed by quantitative RT-PCR and immunoblotting, which demonstrated consistent increases in Abhd4 mRNA and protein levels following bortezomib treatment. Functional analysis further revealed that Abhd4 overexpression promoted early apoptosis, suggesting a mechanistic link between bortezomib-induced Abhd4 elevation and neuronal vulnerability. Therefore, these results suggest that Abhd4 represents a candidate molecular signature associated with bortezomib-induced PN. Although further in vivo validation is needed, these findings warrant further investigation of Abhd4 as a potential contributor to bortezomib-induced PN.