CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
BRAF V600E oncogene expression and TLR4 activation modulate epidermal growth factor receptor (EGFR) in thyroid transformed cells
Autor/es:
PEYRET, V; NAZAR, M; NICOLA, JP; PELLIZAS, CG; MASINI-REPISO, AM
Lugar:
Florianópolis
Reunión:
Congreso; XV Congreso de la Sociedad Latinoamericana de Tiroides; 2013
Institución organizadora:
Sociedad Latinoamericana de Tiroides
Resumen:
Background.
Increased expression of Epidermal Growth Factor Receptor (EGFR) in human
thyroid carcinoma is considered a marker of tumor progression. The Toll-like
receptor 4 (TLR4) has been involved in several human carcinomas. We have
demonstrated an increased TLR4 expression in human thyroid carcinoma tissues
and cell lines. We demonstrated that the induction of the oncogene BRAF V600E
in the normal rat thyroid cell line PCCL3 enhances TLR4 expression. A
transactivation of the EGFR pathway after activation of TLR4 has been described
in various human cancers.
Methods.
Culture of human thyroid anaplastic carcinoma cell line 8505c; PC-BRAF cell
line, a TET-ON system in which PCCL3 thyroid cells express BRAF V600E oncogene
when treated with doxycycline; Western Blot (WB).
Objective.
Analyze the effect of BRAF V600E oncogene induction on EGFR expression in PCCL3
and a possible interaction among TLR4 stimulation and EGFR activation.
Results.
High EGFR expression was displayed (WB) in the BRAF V600E-expressing 8505
cells. When these cells where stimulated by the TLR4 ligand lipopolysaccharide
(LPS) an increase of EGFR phosphorylation was observed at 30 and 45 min. The
expression of EGFR in time course experiments where doxycycline was added to
the culture medium of PC-BRAF cells for three days showed that the presence of
the BRAF V600E oncogene increased EGFR expression in PC-BRAF cells.
Conclusions.
It was concluded that the high EGFR expression in human tumor cells could be
associated with BRAF V600E oncogene expression. A TLR4-dependent EGFR
transactivation in human thyroid cancer cells is suggested.