Regulation of osteosarcoma EGF receptor affinity by phorbol ester and cyclic AMP

Journal Article · Sat Apr 01 00:00:00 EST 1989 · Journal of Bone and Mineral Research; (USA)

DOI:https://doi.org/10.1002/jbmr.5650040209· OSTI ID:5512366

Borst, S E; Catherwood, B D ^[1]

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1. Emory Univ. Department of Medicine, Atlanta, GA (USA)

We studied the binding and degradation of 125I-labeled epidermal growth factor (EGF) by UMR-106 osteosarcoma cells and the regulation of EGF receptor affinity for EGF by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and by treatments that raise intracellular levels of cyclic AMP. Cell surface binding of (125I)EGF to A431 cells reached a plateau after a 30 minute incubation at 37 degrees C but was undetectable in UMR-106 cells. Degradation of (125I)EGF proceeded at a 50-fold higher rate in A431 cells on a per cell basis, but receptor-bound (125I)EGF was internalized and degraded at a 3.5-fold higher rate by UMR-106 cells on a per receptor basis. At 4 degrees C, (125I)EGF labeled a single class of surface binding sites in the UMR-106 cell. Treatment with TPA at 37 degrees C reduced subsequent cell surface binding of (125I)EGF at 4 degrees C a maximum of 80% with an IC50 of 1.25 ng/ml. Maximal TPA reduction of (125I)EGF binding was observed within 5-15 minutes and was due to a reduction in the affinity of cell surface receptors of (125I)EGF without a change in receptor density. Pretreatment of the cells for 4 h with 30 microM forskolin, 1 mM isobutylmethylxanthine (IBMX) plus 30 microM forskolin, or 1 mM IBMX plus 100 ng/ml parathyroid hormone (PTH) attenuated the loss in (125I)EGF binding caused by a subsequent dose of 10 ng/ml of TPA by 17% (p less than 0.0005), 39% (p less than 0.0002), and 35% (p less than 0.002), respectively.

• OSTI ID: 5512366
• Journal Information: Journal of Bone and Mineral Research; (USA), Vol. 4:2; ISSN 0884-0431
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
59 BASIC BIOLOGICAL SCIENCES
AMP
BIOCHEMICAL REACTION KINETICS
GROWTH FACTORS
RECEPTORS
PHORBOL ESTERS
BIOLOGICAL EFFECTS
AFFINITY
IODINE 125
MAN
OSTEOSARCOMAS
PARATHORMONE
PHOSPHOLIPIDS
TRACER TECHNIQUES
ANIMALS
BETA DECAY RADIOISOTOPES
CARCINOGENS
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ESTERS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIPIDS
MAMMALS
MEMBRANE PROTEINS
MITOGENS
NEOPLASMS
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PEPTIDE HORMONES
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
SARCOMAS
SKELETAL DISEASES
VERTEBRATES
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