BACKGROUND This study was done to evaluate the mechanism involved in stem cell factor (SCF) expression and production by lipopolysaccharide (LPS)-stimulated odontoblast (OD)-like cells and to investigate the signal transduction pathway activated in the process. METHODS ODs-like cells (MDPC-23) were stimulated with different LPS concentrations for 1, 6, and 24 hours. SCF expression in OD-like cells was analyzed by reverse-transcriptase polymerase chain reaction, and SCF production was assessed by enzyme-linked immunosorbent assay. In another set of experiments, OD-like cells were pretreated with dexamethasone (DEX), MK886 (MK), p42/44 inhibitor (PD 98059 [PD]), p38 inhibitor (SB 202190 [SB]), or PI3K inhibitor (wortmannin [Wort]) for 30 minutes followed by stimulation with LPS (0.1 μg/mL) for 1 hour. RESULTS OD-like cells stimulated with LPS (0.1 μg/mL) for 1 hour expressed SCF, but SCF production decreased with increasing LPS concentrations (1, 10, and 100 μg/mL). DEX and MK were able to inhibit SCF messenger RNA (mRNA) expression. PD, SB, and Wort inhibited the SCF mRNA expression. CONCLUSIONS LPS-induced SCF mRNA expression and production in OD-like cells occur via leukotriene production or cytokine and/or chemokine formation, activating the p42/44, p38, and PI3K pathways. Data suggest that SCF released by OD-like cells may act as immune response modulators.