| CD56 expression in human myeloma cells derived from the neurogenic gene expression: possible role of the SRY-HMG box gene, SOX4
Abstract CD56 is frequently detected on primary myeloma
cells from more than 80% patients with overt myeloma.
In order to clarify the possible mechanisms of CD56
expression in human myeloma, we underwent screening for
potential targets by microarray analysis, where the
CD56(?) myeloma cell lines showed markedly increased
expressions of transcription factors involved in the neuronal
cell lineage compared to the CD56(-) myeloma cell
lines. Here, we show that among the SOX family of transcription
factors, SOX4 was highly up-regulated and SOX1
was down-regulated in the CD56(?) myeloma cell lines as
well as in primary myeloma cases as confirmed by the
RT-PCR. ChIP analysis of the CD56 promoter region
showed specific bindings of SOX4 in the CD56(?) and
SOX1 in the CD56(-) myeloma cell lines, respectively.
shRNA against SOX1 failed to induce CD56 expression in
CD56(-) myeloma cell line, U266. On the contrary, overexpression
of SOX4 in the CD56(-) myeloma cell line
could induce the CD56 expression. Silencing of SOX4 by
shRNA transfection down-regulated CD56 expression and
induced apoptosis to CD56(?) human myeloma cell line,
AMO1. Thus, induction of SOX4 gene expression might be
responsible for the CD56 expression in human myeloma
cells. |