Proliferation and differnetiation of human squamous carcinoma cell lines and normal keratinocytes: Effects of epidermal growth factor,retinoids, and hydrocortisone |
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Authors: | Maria Ponec Arij Weerheim Johanna Kempenaar Johannes Boonstra |
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Institution: | (1) Department of Molecular Cell Biology, University of Utrecht, 3584 CH Utrecht, The Netherlands;(2) Department of Dermatology, University Hospital Leiden, Rijnsburgerweg 10, 2333 AA Leiden, The Netherlands |
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Abstract: | Summary Exposure of squamous carcinoma cell (SCC) lines, exhibiting high levels of epidermal growth factor (EGF) receptors, to EGF
for 6 d caused a dose-dependent inhibition of cell proliferation. This EGF-induced inhibition of cell proliferation occurred
under both low (0.06 mM) and normal (1.6 mM) Ca2+ concentrations. Furthermore, the extent of EGF-induced inhibition of cell proliferation seemed to be independent of the number
of EGF-receptors. This conclusion is based on the notion that the various SCC lines exhibited an increasing number of EGF
receptors accompanied by a decreasing ability to differentiate, whereas no relationship was observed with the EGF-induced
inhibition of cell proliferation in these cell lines. Retinoids caused also a dose-dependent inhibition of cell proliferation.
The effects of EGF and retinoids were additive, indicating that different regulatory mechanisms are involved. On the other
hand, hydrocortisone caused a stimulation of SCC-proliferation, also independent of EGF. In contrast to SCC cells, EGF did
not affect significantly the rate of proliferation of normal keratinocytes. However, the simultaneous addition of EGF and
hydrocortisone resulted in a significant increase in the rate of keratinocyte proliferation only in cells grown under normal
calcium conditions. Differentiation capacity of normal keratinocytes and SCC lines was not affected by EGF. Furthermore, the
retinoid-induced decrease and hydrocortisone-induced increase of competence of cells to form cornified envelopes was not affected
by EGF. These observations suggest that the action of retinoids and hydrocortisone on both cell proliferation and cell differentiation
occurs independently of EGF receptors.
This work was partly supported by The Netherlands Cancer Foundation (Koningin Wilhelmina Fonds), grant IKW 85–71. |
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Keywords: | keratinocytes squamous carcinoma cells proliferation differentiation epidermal growth factor retinoids |
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