Culture of A-431 human epidermoid carcinoma cells in serum-free medium: effect of culture conditions on the binding of [125I]-epidermal growth factor

3: Final Report on the Safety Assessment of Oleic Acid, Lauric Acid, Palmitic Acid, Myristic Acid, and Stearic Acid

Oleic, Lauric, Palmitic, Myristic, and Stearic Acids are fatty acids with hydrocarbon chains ranging in length from 12 to 18 carbons with a terminal carboxyl group. These fatty acids are absorbed, digested, and transported in animals and humans. Little acute toxicity was observed when Ofeic, Lauric, Palmitic, Myristic, or Stearic Acid or cosmetic formulations containing these fatty acids were given to rats orally at doses of 15-19 g/kg body weight. Feeding of 15% dietary Oleic Acid to rats in a chronic study resulted in normal growth and health, but reproductive capacity of female rats was impaired. Results from topical application of Oleic, Palmitic, and Stearic Acid to the skin of mice, rabbits, and guinea pigs produced little or no apparent toxicity. Studies using product formulations containing Oleic and Stearic acids indicate that neither is a sensitizer or photosensitizing agent. Animal studies also indicate that these fatty acids are not eye irritants. Lauric, Stearic, and Oleic Acids were noncarcinogenic in separate animal tests. In primary and cumulative irritation clinical studies, Oleic, Myristic, and Stearic Acids at high concentrations were nonirritating. Cosmetic product formulations containing Oleic, Lauric, Palmitic, and Stearic Acids at concentrations ranging up to 13% were not primary or cumulative irritants, nor sensitizers. On the basis of available data from studies using animals and humans, it is concluded that Oleic, Lauric, Palmitic, Myristic, and Stearic Acids are safe in present practices of use and concentration in cosmetics.

Study by HPLC-MS of the interaction of platinum antitumor complexes with potato carboxypeptidase inhibitor (PCI)

The interaction of the well-known antitumor drug cisplatin cis-[PtCl(2)(NH(3))(2)] and the compound trans-[PtCl(2)NH(3)(4-hydroxymethylpyridine)] with the small protein potato carboxypeptidase inhibitor (PCI) and a PCI mutant in which glycine-39 was substituted by methionine has been followed by HPLC/mass spectrometry. Our results showed that both Pt drugs were able to bind PCI through Met-39 and histidines in mutated PCI, whereas only the trans complex interacted significantly with wild PCI. In the cytotoxic studies, the monofunctional adduct PCI-Met-cisplatin was neither more active nor more selective than cisplatin itself when tested against three tumor cell lines with different number of EGF receptors. Those results suggested that the poor activity of the adduct could be just due to the small fraction of cisplatin which was decoordinated from the adduct and able to penetrate the tumor cells, as well as to the changes in the structure of the platinum drug after the loss of NH(3) groups upon binding PCI-Met.

Characterization of the metabolic turnover of epidermal growth factor receptor protein in A-431 cells

The metabolism of the receptor for epidermal growth factor (EGF) in A-431 cells has been measured by labeling the receptor in vivo with radioactive amino acid precursors and then determining, by immunoprecipitation with specific anti-EGF receptor antisera, the rate of degradation of the receptor when the cells are placed in a nonradioactive medium. The rate of EGF receptor degradation (t1/2 = 20 hr) was faster than the rate of degradation of total cell protein (t1/2 = 52 hr). When EGF was added at the beginning of the chase, the half-life of prelabeled receptor decreased to 8.9 hr. This decrease was specific, as the level of total cellular protein and another plasma membrane protein, the transferrin receptor, were relatively unaffected by EGF. The carbohydrate portion of the receptor is degraded, in the presence or absence of EGF, at approximately the same rate as the protein moiety. The amount of EGF receptor protein in A-431 cells has been quantitated by radiolabeling total cellular protein and quantitating the immunoprecipitable receptor. The EGF receptor constitutes approximately 0.15% of the total cell protein in A-431 cells. These cells, therefore, have approximately 30 times more EGF receptor protein than fibroblasts. The EGF receptor constitutes an even higher proportion of 3H-glucosamine- or 3H-mannose-labeled macromolecules in A-431 cells, 1.5% or 5.2%, respectively. The EGF receptor from A-431 cells can easily be identified by submitting carbohydrate-labeled, solubilized cells to electrophoresis as described by Laemmli (1970).