Phosphoinositide signaling in nuclei of Friend cells: tiazofurin down-regulates phospholipase C beta 1.
Previous investigations have demonstrated the presence of conventional lipid kinases and phospholipase C (PLC) activities in nuclei of Friend erythroleukemia cells. Moreover, when Friend erythroleukemia cells are treated for 96 h with the antitumor drug tiazofurin, the induction of erythroid differentiation is accompanied by changes in amounts of both phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate due to the inhibition of an uncharacterized nuclear PLC activity. Here, we show that the nuclear PLC beta 1 isoform is down-regulated by tiazofurin (5 microM) treatment of Friend erythroleukemia cells as shown by both Western blot and Northern blot analyses for PLC beta 1 message. This indicates that PLC beta 1 down-regulation is tightly linked with erythroid differentiation of Friend erythroleukemia cells and that the autonomous nuclear signaling via inositol lipid cycle can be controlled by the antitumor drug tiazofurin.
Manzoli
L
L
Institute of Human Morphology, University of Chieti, Italy.
Billi
A M
AM
Gilmour
R S
RS
Martelli
A M
AM
Matteucci
A
A
Rubbini
S
S
Weber
G
G
Cocco
L
L
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015152:Blotting, Northern; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects*; D005622:Friend murine leukemia virus; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D004915:Leukemia, Erythroblastic, Acute / Q000188:drug therapy* / Q000201:enzymology* / Q000821:virology; D051379:Mice; D010716:Phosphatidylinositols / Q000502:physiology*; D054799:Phospholipase C beta; D012254:Ribavirin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology*; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors* / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D010716:Phosphatidylinositols; D012254:Ribavirin; D010738:Type C Phospholipases; D054799:Phospholipase C beta; C518034:Plcb1 protein, mouse; C033706:tiazofurin