Role of protein kinase C in the phosphatidylserine-induced inhibition of DNA synthesis in blood mononuclear cells

1992 ◽  
Vol 24 (3) ◽  
pp. 191-201 ◽  
Author(s):  
Elisabeth Caselli ◽  
Fabrizio Bellini ◽  
Ponzin Diego ◽  
O.Roberto Baricordi ◽  
Alessandro Bruni
Life Sciences ◽  
2006 ◽  
Vol 80 (3) ◽  
pp. 181-186 ◽  
Author(s):  
Masayuki Niwa ◽  
Koichi Hotta ◽  
Akira Hara ◽  
Kouseki Hirade ◽  
Hidenori Ito ◽  
...  

1993 ◽  
Vol 264 (1) ◽  
pp. C71-C79 ◽  
Author(s):  
R. V. Sharma ◽  
R. C. Bhalla

This study examines the role of protein kinase C (PKC) in platelet-derived growth factor (PDGF)-induced vascular smooth muscle (VSM) cell proliferation and initial signaling events. A 24-h pretreatment of VSM cells with 200 nM phorbol 12-myristate 13-acetate (PMA) completely abolished immunologically reactive PKC activity. Depletion of PKC activity from VSM cells did not attenuate PDGF-stimulated [3H]thymidine incorporation compared with control cells. Similarly, acute activation of PKC by treatment with 200 nM PMA for 10 min had no effect on PDGF-mediated [3H]thymidine incorporation. Both PMA and PDGF increased c-fos induction to the same magnitude; however, treatment with PMA did not induce DNA synthesis in these cells. In PKC-depleted cells PDGF-mediated c-fos induction was reduced by 50-60%, while DNA synthesis in response to PDGF stimulation was not reduced. PKC depletion did not alter PDGF-stimulated increase in cytosolic calcium levels, 125I-PDGF binding, or receptor autophosphorylation. On the basis of these results, we conclude that PKC activation and c-fos induction do not play a significant role in PDGF-mediated mitogenesis in VSM cells.


2005 ◽  
Vol 23 (9) ◽  
pp. 1875-1884 ◽  
Author(s):  
Jeremy Kortmansky ◽  
Manish A. Shah ◽  
Andreas Kaubisch ◽  
Amanda Weyerbacher ◽  
Sandy Yi ◽  
...  

Purpose Preclinical studies indicate that the cyclin-dependent kinase and protein kinase C inhibitor 7-hydroxystaurosporine (UCN-01) potentiates the cytotoxic effects of fluorouracil (FU). We designed a phase I clinical trial of FU in combination with UCN-01. Patients and Methods FU was administered as a weekly 24-hour infusion. Doses were escalated in successive cohorts according to a modified Fibonacci design. UCN-01 was administered once every 4 weeks, immediately after disconnection from FU, at a dose of 135 mg/m2 over 72 hours in cycle 1 and 67.5 mg/m2 over 36 hours in subsequent cycles. FU and UCN-01 pharmacokinetics were obtained on all patients, and thymidylate synthetase (TS) activity was measured in peripheral-blood mononuclear cells by reverse-transcriptase polymerase chain reaction. Results We escalated the weekly FU dose to 2,600 mg/m2 in combination with once a month infusions of UCN-01. Dose-limiting toxicity included arrhythmia and syncope. Other toxicities included hyperglycemia, headache, and nausea and vomiting. The mean maximal plasma concentration of UCN-01 was 33.5 μmol/L. There was significant interpatient variability, which correlated with plasma concentrations of alpha-1 acid glycoprotein. FU was rapidly cleared and the dose had no effect on the area under the curve of UCN-01. Changes in TS expression were detectable in peripheral-blood mononuclear cells after administration of UCN-01 but did not correlate with toxicity or activity. We observed no objective response, although seven patients had stable disease, six of whom had received prior fluoropyrimidines. Conclusion The combination of weekly infusions of FU and monthly UCN-01 can be administered safely and warrants further study in phase II trials. The recommended phase II dose of FU in combination with monthly UCN-01 is 2,600 mg/m2.


Sign in / Sign up

Export Citation Format

Share Document