HGF is released from buccal fibroblasts after smokeless tobacco stimulation

To investigate the effect of smokeless tobacco (ST) on (1) HGF, KGF and GM-CSF expression by buccal fibroblasts and (2) on keratinocyte and fibroblast proliferation. Buccal fibroblasts were stimulated with different concentrations of ST extracts in a double dilution from 0.50% w/v to 0.03% w/v. Supernatant was collected after 24/48/72/96 h and assayed for HGF, KGF, and GM-CSF by ELISA. The amount of RNA was used as an indicator of fibroblast cell number. Buccal epithelial cell proliferation was determined by CyQUANT proliferation assay. The amount of HGF and KGF in the supernatant was dependent on exposure time and on concentration of the tobacco extract. High concentration increased production of HGF 4-fold. KGF production was doubled when high concentration of tobacco was used, low concentration did not stimulate cells. GM-CSF production was low in both stimulated and non-stimulated cells. Keratinocytes and fibroblasts showed no increase in proliferation after stimulation with increased concentrations of ST. The results suggest that HGF and KGF may play an important role as a paracrine growth factor in epithelial hyperplasia in ST lesions.