1,25(OH)2D3 incubation up-Regulates HOX A9 gene in HL-60 cells.

There are many genes involved in vitamin D dependent differentiation of acute myeloid leukaemia cell line HL-60 cells. Involvement of HOX genes in leukaemia and differentiation is just beginning to be appreciated. In order to understand the relationship with 1,25(OH)2D3 dependent differentiation of myeloid leukaemia, we studied the expression of HOX A9 gene. HL-60 cells were exposed to 1,25(OH)2D3 for 24 and 72 hours. Gene expression were investigated using quantitative real-time RT-PCR (LightCycler). HOX A9 levels were found upregulated after 1,25(OH)2D3 treatment, compared to housekeeping RPS9 and HPRT genes. Our study is the first attempt to quantification of HOX A9 gene during 1,25(OH)2D3 treatment, using this technology. We suggest that there is a clear relationship between differentiation induction and over-expression of HOX A9 gene in HL-60 cells. Possible correlation of high expression levels of HOX A9 gene in AML pathogenesis remains to be established.