Cytoplasmic Macrophage Colony-stimulating Factor Activates Pi3k-akt-mtor-p70s6k Signalings In MCF-7 Cells

OBJECTIVE The aim is to explore the effect of cytoplasmic M-CSF on PI3K/Akt/mTOR/p70S6K signalings in human breast cancer MCF-7 cells.METHODS Human breast cancer MCF-7 cell, MCF-7-M cell (pCMV/cyto/myc-M-CSF transfected-MCF-7 cell that highly expresses nuclear M-CSF, referred as to MCF-7-M cell) and MCF-7-C cell (vector pCMV/cyto/myc transfected MCF-7 cell, referred as to MCF-7-C cell) were cultured or preincubated with PI3K inhibitors LY294002 for 30 min. The expression and phosphorylation of PI3K, Akt, mTOR and p70S6K was assayed by Western blot. The mRNA expression of PI3K,Akt,mTOR and p70S6K was detected by RT-PCR.RESULTS The results from RT-PCR showed that mRNA expression of PI3K,Akt,mTOR and p70S6K is markedly higher in MCF-7-M cells than that in either MCF-7-C cells or MCF-7cells(p<0.01). The results from Western blot indicated that both protein expression and phosphorylation of PI3K,Akt,mTOR and p70S6K is significant higher in MCF-7-M cells than that in either MCF-7-C cells or MCF-7cells(p<0.05). PI3K inhibitors LY294002 remarkably decreased the phosphorylation of Akt in MCF-7-C cells, compared with either MCF-7-C cell or MCF-7 cell (p<0.05).CONCLUSION Cytoplasmic M-CSF induces the mRNA and protein expression and phosphorylation of PI3K, Akt, mTOR and p70S6K. Cytoplasmic M-CSF acitvates PI3K-Akt-mTOR-p70S6K signalings.