INVESTIGADORES
MARTIN Gabriela Adriana
artículos
Título:
Epidermal growth factor in NMU-induced mammary tumors in rats
Autor/es:
G. MARTIN, G. CRICCO, C. DAVIO, C. COCCA, E. RIVERA AND R. BERGOC
Revista:
BREAST CANCER RESEARCH AND TREATMENT
Editorial:
Kluver Academic
Referencias:
Año: 1998 vol. 48 p. 175 - 185
ISSN:
0167-6806
Resumen:
In this work we analyze the hypothesis that tumors induced by ip N-nitroso-N-methylurea injection express
EGF-like peptides and EGF receptors which could be involved in the response to hormone manipulation.
EGF receptors (EGFR) were determined in the purified membrane fraction of tumors from control and
ovariectomized (OVX) animals and no significant differences were found in either maximal binding capacities
(Q) or dissociation constants (Kd) between them. Neither did we observe differences between tumors
that regressed (HR) or continued growing (HU) after ovariectomy. In order to test the ability of EGFR to
trigger a biological response we measured the production of second messengers inositol triphosphates (IP3)
and cAMP levels; we found that EGF increases IP3 production in a dose-dependent way, while cAMP levels
were not affected. In addition, EGF was able to induce in vitro cell proliferation in a concentration-dependent
manner when tested in primary cultures of tumor cells by the clonogenic soft agar technique. EGF/TGF-a3)
and cAMP levels; we found that EGF increases IP3 production in a dose-dependent way, while cAMP levels
were not affected. In addition, EGF was able to induce in vitro cell proliferation in a concentration-dependent
manner when tested in primary cultures of tumor cells by the clonogenic soft agar technique. EGF/TGF-a3 production in a dose-dependent way, while cAMP levels
were not affected. In addition, EGF was able to induce in vitro cell proliferation in a concentration-dependent
manner when tested in primary cultures of tumor cells by the clonogenic soft agar technique. EGF/TGF-ain vitro cell proliferation in a concentration-dependent
manner when tested in primary cultures of tumor cells by the clonogenic soft agar technique. EGF/TGF-aa
activity was determined by a radioreceptor assay in tumor cytosols from control and OVX rats. Results
showed a trend to lower values in tumors from OVX rats, but no differences between HR and HU tumors. A
positive correlation was found between EGF/TGF-a activity and progesterone receptor maximal binding
capacity. When we tested the action of estradiol and EGF added together to primary cultures of tumor cells we
found an additive effect on cell proliferation. The study of steady state mRNA levels showed that E2 increases
PgR and c-myc mRNA levels in HR but not in HU tumors.
In conclusion, the autocrine loop EGFR-EGF/TGF-a present in all tumors is hormonally regulated, possibly
by Pg, but is not related to the tumor response to ovariectomy.a activity and progesterone receptor maximal binding
capacity. When we tested the action of estradiol and EGF added together to primary cultures of tumor cells we
found an additive effect on cell proliferation. The study of steady state mRNA levels showed that E2 increases
PgR and c-myc mRNA levels in HR but not in HU tumors.
In conclusion, the autocrine loop EGFR-EGF/TGF-a present in all tumors is hormonally regulated, possibly
by Pg, but is not related to the tumor response to ovariectomy.2 increases
PgR and c-myc mRNA levels in HR but not in HU tumors.
In conclusion, the autocrine loop EGFR-EGF/TGF-a present in all tumors is hormonally regulated, possibly
by Pg, but is not related to the tumor response to ovariectomy.a present in all tumors is hormonally regulated, possibly
by Pg, but is not related to the tumor response to ovariectomy.