INTERLEUKIN-1-BETA AND TRANSFORMING GROWTH-FACTOR-ALPHA EPIDERMAL GROWTH-FACTOR INDUCE EXPRESSION OF M(R) 95,000 TYPE-IV COLLAGENASE GELATINASE AND INTERSTITIAL FIBROBLAST-TYPE COLLAGENASE BY RAT MUCOSAL KERATINOCYTES

Rat mucosal keratinocytes serially propagated under permanently serum- free conditions responded to interleukin (IL)-1beta/IL-alpha and to tr ansforming growth factor (TGF)-alpha/epidermal growth factor (EGF) (as well as to 12-O-tetradecanoylphorbol-13-acetate (TPA)) by upregulatio n of M(r) 95,000 gelatinase (MMP-9)(M(r) 95K GL) and fibroblast-type c ollagenase (MMP-1) (FIB-CL), whereas control cells expressed barely de tectable levels of either of these enzymes. The cells secreted 8-10 mu g/10(6) cells/day (M(r) 95K GL) and 2-3 mug/10(6) cells/day (FIB-CL) o f enzyme protein for at least 24 h when maximally induced. This level was attained only after a 24-h lag period, and the earliest emergence of enzyme protein in the culture medium required 10-14 h. IL-1beta was by far the most potent cytokine with maximal effect already at 10(-10 ) M, whereas IL-1alpha, TGF-alpha, and EGF required 20-100-fold higher concentrations. Pretreatment of the cells with TPA (10(-7) M) abolish ed the subsequent response to IL-1beta, TGF-alpha, and EGF and at the same time resulted in >90% reduction of cytosolic protein kinase C act ivity. Surprisingly, staurosporine, a potent kinase inhibitor, not onl y failed to block growth factor/cytokine responses but itself stimulat ed expression of the enzymes at a magnitude comparable to TPA. The ind ucing effect of TGF-alpha/EGF was down-regulated by 70-85% by 10(-7) M dexamethasone. Dexamethasone was less effective in ablating the IL-1b eta response yielding 60% reduction M(r) 95K GL and little or no reduc tion of FIB-CL. Dexamethasone also failed to block the TPA response.