REGULATION OF THE HUMAN LEUKEMIA INHIBITORY FACTOR (LIF) PROMOTER IN HEC-1B ENDOMETRIAL ADENOCARCINOMA CELLS

Leukaemia inhibitory factor (LIF) is a pleiotropic cytokine which has been found to be expressed in the human endometrium and to play an imp ortant role in human reproduction. In the present study we investigate d expression and regulation of the human LIF promoter in HEC-1B endome trial adenocarcinoma cells using a luciferase reporter plasmid bearing a 666 bp promoter fragment (h666LIF-Luc) in transient transfection as says. HEC-1B cells were first shown by reverse transcription-polymeras e chain reaction (RT-PCR) to be able to produce endogenous LIF mRNA. T he! LIF promoter was efficiently transcribed in HEC-1B cells, showing much higher levels of basal activity than in the previously studied Ju rkat T-lymphoma cells and SKUT-1B uterine mesodermal tumour cells. The activity of the LIF promoter was stimulated in HEC-1B cells by a comb ination of phorbol ester (TPA) and ionomycin, which we had previously found to strongly induce its activity in Jurkat T-lymphoma cells. We n ext studied the effect of progestin (medroxyprogesterone acetate; MPA) on the LIF promoter activity in HEC-1B cells. The LIF promoter was no t stimulated by MPA treatment in the presence of transfected progester one receptor B (PR-B) expression vector in HEC-1B cells, while we had previously described its induction by MPA in SKUT-1B cells. This indic ates that progestin-dependent regulation of the LIF promoter in uterin e tumour cells is different in cells of epithelial and mesodermal orig in.