Apolipoprotein B mRNA editing enzyme catalytic subunit 3B (APOBEC3B)

Apolipoprotein B mRNA editing enzyme catalytic subunit 3B (APOBEC3B) is a member of the zinc-dependent cytidine deaminase enzyme family, which catalyzes the deamination of cytosine to uracil in single-stranded DNA and, to a lesser extent, RNA[1][2][5][7]. It is predominantly localized in the nucleus, where it plays an important role in restricting DNA-based pathogens such as retroviruses and transposable elements by introducing hypermutations into their genomes[1][7]. However, in cancer cells, APOBEC3B is frequently overexpressed and acts as a major endogenous source of somatic mutations, contributing to genetic heterogeneity and tumor evolution—especially in breast, head/neck, lung, bladder, cervical, and other cancers[1][2][4][5]. APOBEC3B prefers target motifs such as 5′-TC dinucleotides and exhibits specificity for single-stranded DNA stem-loop or hairpin secondary structures[1][5]. In addition to its established role in DNA editing, evidence suggests that APOBEC3B may also participate in selective RNA editing, impacting gene regulation and further expanding protein diversity[2][3]. As such, it is regarded as both a critical restriction factor in innate immunity and a significant mutagenic driver in carcinogenesis[1][2][7]. No clinically approved drugs directly target APOBEC3B, but it is a focus of ongoing anti-cancer drug discovery[1].

Other names

DNA dC->dU-editing enzyme APOBEC-3BA3BPHRBNLFLJ21201Phorbolin-1-related proteinPhorbolin-2/3phorbolin 3APOBEC1LARCD3ARP4DJ742C19.2bK150C2.2catalytic polypeptide-like 3Bcytidine deaminaseprobable DNA dC->dU-editing enzyme APOBEC-3B

For potential inhibitors: blockade of cytidine deaminase activity to prevent C-to-U mutagenesis in DNA. Inhibition of substrate binding or catalytic site activity to suppress tumor evolution and resistance[1][5]