[Inhibitory effect of epidermal growth factor on apoptosis in HaCaT keratinocytes induced by TNF-alpha].
OBJECTIVE
To explore the effect of epidermal growth factor (EGF) on apoptosis induced by TNF-alpha and the expression of PPARbeta in HaCaT keratinocytes.


METHODS
HaCaT keratinocytes were cultured and randomly divided into A (normal control), B (with treatment of 10 ng/ml TNF-alpha for 24 hours), C (with treatment of 20 ng/ml TNF-alpha for 24 hours), D (with treatment of 10 ng/ml TNF-alpha after 20 ng/ml EGF treatment for 4 hours), E (with treatment of 20 ng/ml TNF-alpha after 20 ng/ml EGF treatment for 4 hours) groups. The apoptosis of HaCaT keratinocytes was observed by flow cytometry. The proliferative activity of HaCaT keratinocytes was evaluated by MTT method. The activity of caspase-3 was analyzed with caspase colorimetric assay Kit. The changes in the mRNA and protein expression of PPARbeta in HaCaT keratinocytes were observed by RT-PCR and western-blotting after treatment with different concentrations (5, 10, 20, 40 ng/ml) of EGF for 4 or 24 hrs.


RESULTS
Compared with A and B groups [(32 +/- 6)%, (57 +/- 6)%], the apoptosis of HaCaT keratinocytes in D and E groups were significantly increased [(20 +/- 3)%, (28 +/- 4)%, respectively, P < 0.01], while the survival rate of HaCaT keratinocytes in D and E groups increased, and the caspase-3 activity were decreased (P < 0.01). The expression of PPARbeta mRNA and protein in HaCaT keratinocytes reached the peak with the treatment of 20 ng/ml EGF.


CONCLUSIONS
EGF can inhibit the apoptosis of HaCaT keratinocytes induced by TNF-alpha, and it can also increase the expression of PPARbeta.
Liang
Peng-fei
PF
Department of Burns and Plastic Surgery, Xiangya Hospital, Central South University, Changsha, P. R. China.
Huang
Xiao-yuan
XY
Chen
Bei-fang
BF
Jiang
Bi-mei
BM
Long
Jian-hong
JH
Zhang
Pi-hong
PH
Yang
Xing-hua
XH
D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D048068:PPAR-beta / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D048068:PPAR-beta; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D004815:Epidermal Growth Factor; D053148:Caspase 3