Upregulation of the expression of epidermal growth factor and its receptor in gingiva upon cyclosporin A treatment.
BACKGROUND
To understand the roles of epidermal growth factor (EGF) and EGF receptor (EGF-R) in cyclosporin A (CsA)-induced gingival overgrowth, expression of EGF and EGF-R upon CsA treatment was examined in an oral epidermoid carcinoma cell line of humans (OECM-1) and in edentulous gingiva of rats.


METHODS
In vitro study: after CsA treatment, OECM-1 cells were harvested to evaluate their mRNA and protein expression of EGF and EGF-R with reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, and immunocytochemistry (ICC). In vivo study: 3 weeks after extraction of all maxillary molars, 20 male Sprague-Dawley rats were assigned to a CsA group (30 mg/kg, fed daily) and a control group. Five rats per group were sacrificed at weeks 1 and 4. Edentulous ridge specimens were obtained for evaluating their mRNAs and protein expression with RT-PCR, real-time RT-PCR, and immunohistochemistry (IHC). In both in vitro and in vivo experiments, the proliferating potential of epithelial cells was examined by the presence of proliferating cell nuclear antigen (PCNA).


RESULTS
In vitro: dose-dependently increased mRNA expression of EGF and EGF-R in OECM-1 cells was noted after CsA treatment. Protein expressions of EGF and EGF-R were higher in OECM-1 with CsA treatment than without CsA. In vivo: higher mRNA and protein expressions of EGF and EGF-R were also observed in the gingival tissues of CsA-treated rats. In both in vitro and in vivo experiments, greater PCNA expression after CsA treatment was demonstrated.


CONCLUSIONS
Higher expression of EGF and EGF-R upon CsA therapy was observed in OECM-1 epithelial cells of humans and in edentulous gingiva of rats. We suggest that CsA could upregulate gene and protein expression of EGF and EGF-R, and the upregulation may play a role in gingival overgrowth.
Department of Periodontology, School of Dentistry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Yu-Tang
YT
Chin
Yen-Teen
YT
Chen
Hsiao-Pei
HP
Tu
E-Chin
EC
Shen
Cheng-Yang
CY
Chiang
Ching-Hwa
CH
Gau
Shin
S
Nieh
Earl
E
Fu
D000818:Animals; D045744:Cell Line, Tumor; D016572:Cyclosporine / Q000008:administration & dosage / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D004815:Epidermal Growth Factor / Q000096:biosynthesis*; D066246:ErbB Receptors / Q000096:biosynthesis*; D015870:Gene Expression; D019214:Gingival Overgrowth / Q000139:chemically induced / Q000378:metabolism*; D006651:Histocytochemistry; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000009:adverse effects*; D008297:Male; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
D007166:Immunosuppressive Agents; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D016572:Cyclosporine; D066246:ErbB Receptors