Cellular pharmacology of D-3-azido-3-deoxy-myo-inositol, an inhibitor of phosphatidylinositol signaling having antiproliferative activity.
D-3-Azido-3-deoxy-myo-inositol (3AMI) is an inhibitor of the growth of v-sis-transformed NIH 3T3 cells but not of wild-type NIH 3T3 cells, whose effects may be mediated through the phosphatidylinositol-3'-kinase pathway. We studied some properties of the cellular pharmacology of 3AMI using high-specific-activity [3H]-3AMI. The uptake of [3H]-3AMI by wild-type NIH 3T3 and v-sis NIH 3T3 cells was similar. [3H]-3AMI was a substrate for phosphatidylinositol synthetase, with the maximal velocity (Vmax) being 1.0 nmol min-1 mg-1 and the Michaelis constant (Km) being 23 mM. Corresponding values obtained for [3H]-myo-inositol as a substrate were 5.5 nmol min-1 mg-1 and 3.2 mM. [3H]-3AMI was incorporated into the cellular inositol lipids of v-sis NIH 3T3 cells to a similar extent as that observed for [3H]-myo-inositol but was not incorporated into the inositol lipids of wild-type NIH 3T3 cells. The [3H]-3AMI incorporated by the v-sis NIH 3T3 cells was present in the phosphatidylinositol and phosphatidylinositol phosphate fractions but not in bisphosphorylated phosphatidylinositol. myo-Inositol antagonized the growth-inhibitory effects of 3AMI. The v-sis NIH 3T3 cells were found to be more sensitive than the wild-type NIH 3T3 cells to growth inhibition (without 3AMI) caused by the removal of myo-inositol from the medium. The results of the study suggest that 3AMI is an antimetabolite of myo-inositol. The relative sensitivity of v-sis NIH 3T3 and some other cells to 3AMI may be a reflection of increased myo-inositol requirements for the growth of these cells as compared with wild-type NIH 3T3 cells.
Brunn
G
G
Mayo Clinic and Foundation, Rochester, Minnesota.
Fauq
A H
AH
Chow
S
S
Kozikowski
A P
AP
Gallegos
A
A
Powis
G
G
D016475:3T3 Cells; D000818:Animals; D051607:CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase; D002455:Cell Division / Q000187:drug effects*; D007294:Inositol / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism* / Q000494:pharmacology; D007295:Inositol Phosphates / Q000096:biosynthesis*; D018021:Lithium Chloride / Q000494:pharmacology; D051379:Mice; D010743:Phospholipids / Q000378:metabolism; D017855:Transferases (Other Substituted Phosphate Groups) / Q000037:antagonists & inhibitors
D007295:Inositol Phosphates; D010743:Phospholipids; D007294:Inositol; C090894:3-azido-3-deoxy-myo-inositol; D017855:Transferases (Other Substituted Phosphate Groups); D051607:CDP-Diacylglycerol-Inositol 3-Phosphatidyltransferase; D018021:Lithium Chloride