NB4

NB4 is a human leukemia cell line derived from a patient with acute promyelocytic leukemia (APL). It is widely used in hematology and cancer research as an in vitro model of APL and retinoid-based therapies. The cell line carries the t(15;17) chromosomal translocation, producing the PML-RARA fusion gene that drives leukemogenesis and confers sensitivity to differentiation therapy with all-trans retinoic acid (ATRA).

In culture, NB4 cells are typically maintained as a suspension cell line under standard mammalian cell culture conditions. They are commonly grown in RPMI 1640 or similar medium supplemented with fetal bovine serum and antibiotics, under appropriate incubator conditions. NB4 cells exhibit promyelocyte-like morphology and can be induced to differentiate toward mature granulocytes with retinoic acid or other differentiating agents.

Research uses of NB4 include studying retinoic acid receptor signaling, the molecular mechanisms of PML-RARA–driven leukemogenesis, and the cellular processes underlying leukemic differentiation and apoptosis. The line also serves as a platform for evaluating new therapeutic compounds and their mechanisms of action in the context of APL. NB4 is available from major cell repositories such as ATCC, enabling broad access for experimental replication and comparative studies. Safety considerations align with standard practices for human-derived cell lines, typically requiring biosafety level 2 containment.

Limitations of NB4 include genetic drift with extended culture, clonal variation, and the general caveat that cell lines may not fully recapitulate in vivo disease, so findings should be validated in additional models.