Phosphoinositide signaling in nuclei of Friend cells: tiazofurin down-regulates phospholipase C beta 1
Manzoli, L.; Billi, A.M.; Gilmour, R.S.; Martelli, A.M.; Matteucci, A.; Rubbini, S.; Weber, G.; Cocco, L.
Cancer Research 55(14): 2978-2980
1995
ISSN/ISBN: 0008-5472 PMID: 7606713 Document Number: 440804
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 b 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 mu-M) 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.