Inhibition of calcium-dependent protein kinase C by hexadecylphosphocholine and 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine do not correlate with inhibition of proliferation of HL60 and K562 cell lines
| Autor: | Clemens Unger, Eduard A. M. Fleer, Hansjoerg Eibl, K. Berkovic, D. Berkovic |
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| Rok vydání: | 1994 |
| Předmět: |
Cancer Research
HL60 Phosphorylcholine Antineoplastic Agents Alkylphosphocholine Diglycerides chemistry.chemical_compound Cytosol Tumor Cells Cultured Humans Protein Kinase C Protein kinase C Phosphocholine Leukemia Dose-Response Relationship Drug biology Kinase Cell Membrane Phospholipid Ethers Enzyme assay Oncology Biochemistry chemistry Cell culture biology.protein Tetradecanoylphorbol Acetate Cell Division |
| Zdroj: | European Journal of Cancer. 30:509-515 |
| ISSN: | 0959-8049 |
| Popis: | We investigated the hypothesis that the antiproliferative effect of hexadecylphosphocholine (HePC) and 1- O -octadecyl-2- O -methyl-rac-glycero-3-phosphocholine (ET-18-OCH 3 ) is mediated through the inhibition of cellular protein kinase C (PKC). In the sensitive HL60 cell line, id 50 and ld 50 values of 5.6 and 5.3 μM, respectively (HePC), and of 3.8 and 4.2 μM, respectively (ET-18-OCH 3 ) were obtained. In the more resistant K562 cell line, these values were 69.1 and > 97 μM, respectively (HePC) and 7.8 and 76.8 μM, respectively (ET-18-OCH 3 ). Treatment of both cell lines with HePC and ET-18-OCH 3 (25 μM) for 2 h did not lead to PKC translocation. However, a 30% reduction of PKC activity, mainly due to a decrease in the cytosolic compartment, was found. Half maximal stimulation of PKC translocation by phorbolester (TPA) in HL60 and K562 cells, which were pretreated for 2 h with 25 μM of the lipids, resulted in a 20–30% decrease of membrane-bound PKC, whereas the cytosolic form was found to be unchanged. In the same experimental setting, dioctanoylglycerol (DIC 8 )-stimulated PKC translocation was not affected by HePC or ET-18-OCH 3 . However, a 10–20% reduction of PKC enzyme activity in the membrane and in the cytosolic fraction was obtained. These findings indicate that HePC and ET-18-OCH 3 do not interfere with PKC translocation but rather mediate a general decrease of the enzyme activity in the membrane and cytosol of the cells. Since the extent of PKC inhibition was somewhat similar in the sensitive HL60 and the resistant K562 cell line, inhibition of PKC is probably not a prerequisite for the antiproliferative action of HePC and ET-18-OCH 3 . |
| Databáze: | OpenAIRE |
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