Expression, regulation, and function of P2X4purinergic receptor in human cervical epithelial cells

2002 ◽  
Vol 282 (1) ◽  
pp. C84-C93 ◽  
Author(s):  
George I. Gorodeski
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Epithelial Cells ◽  
Vitamin A ◽  
Phase I ◽  
Phase Ii ◽  
Calcium Influx ◽  
Receptor Mrna ◽  
Kinase C ◽  
Junctional Resistance

Micromolar concentrations of ATP stimulate biphasic change in transepithelial conductance across CaSki cultures on filters, an acute transient increase ( phase I response; triggered by P2Y2receptor and mediated by calcium mobilization-dependent cell volume decrease) followed by a slower decrease in permeability ( phase II response). Phase II response is mediated by augmented calcium influx and protein kinase C-dependent increase in tight junctional resistance. The objective of the study was to determine the role of P2X4receptor as a mediator of phase II response. Human cervical epithelial cells express P2X4receptor mRNA (1.4-, 2.2-, and 4.4-kb isoforms by Northern blot analysis) and P2X4protein. Depletion of vitamin A reversibly downregulated P2X4receptor mRNA and protein and ATP-induced calcium influx. Depletion of vitamin A abrogated phase II response, and the effect could be partially reversed only with retinoic acid receptor (RAR)-selective retinoids but not retinoid X receptor (RXR) agonists. Depletion of vitamin A also abrogated protein kinase C increase in tight junctional resistance, and the effect could not be reversed with retinoids. Depletion of vitamin A also abrogated phase I increase in permeability and reversibly downregulated P2Y2receptor mRNA and ATP-induced calcium mobilization. However, in contrast to phase II response, both RAR and RXR agonists could fully reverse those effects. These results suggest that phase IIresponse is mediated by a P2X4receptor mechanism.

Phase I Dose Escalation and Pharmacokinetic Study of Enzastaurin, an Oral Protein Kinase C Beta Inhibitor, in Patients With Advanced Cancer

2006 ◽  
Vol 24 (25) ◽  
pp. 4092-4099 ◽  
Author(s):  
Michael A. Carducci ◽  
Luna Musib ◽  
Merrill S. Kies ◽  
Roberto Pili ◽  
Mylene Truong ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Phase I ◽  
Advanced Cancer ◽  
Phase Ii ◽  
Dose Escalation ◽  
Stable Disease ◽  
Recommended Dose ◽  
Once Daily ◽  
Kinase C

Purpose This phase I study was conducted to determine the recommended dose of enzastaurin, an oral protein kinase C beta (PKCβ) inhibitor, for phase II trials. Secondary objectives were maximum-tolerated dose (MTD), pharmacokinetics (PK), toxicity, and response. Patients and Methods Patients at least 18 years of age with advanced cancer and an Eastern Cooperative Oncology Group performance status of 0 or 1 lower received enzastaurin orally once daily at a starting dose of 20 mg. Dose escalation proceeded using a modified Simon design. Results All 47 patients enrolled (mean age, 58 years) received at least one dose of enzastaurin, with a median of two cycles (range, one to 17 cycles). Prevalent malignancies were lung (n = 10) and head and neck cancers (n = 9). Although no MTD was identified up to 700 mg/d, 525 mg was chosen as the recommended dose, and 12 additional patients were accrued at that level. Three dose-limiting toxicities (QTc changes) occurred: one at the 700-mg dose (patient discontinued), and two in the expansion cohort at the 525-mg dose. Total analytes (enzastaurin and its metabolites) exposure increased with increasing doses up to 240 mg, and appeared to plateau at 525 and 700 mg. Grade 1 chromaturia, fatigue, and other GI toxicities were the most common, while no clinically significant grade 3/4 toxicities occurred. Two deaths, unrelated to enzastaurin, occurred. Twenty-one patients (45%) achieved stable disease (SD) for two to 16 cycles. Conclusion On the basis of plasma exposures and safety data, enzastaurin 525 mg once daily is the recommended phase II dose. Enzastaurin is well tolerated up to 700 mg/d. Evidence of early activity was seen with significant stable disease.

scholarly journals Regulated CD44 Cleavage under the Control of Protein Kinase C, Calcium Influx, and the Rho Family of Small G Proteins

1999 ◽  
Vol 274 (36) ◽  
pp. 25525-25534 ◽  
Author(s):  
Isamu Okamoto ◽  
Yoshiaki Kawano ◽  
Mitsuhiro Matsumoto ◽  
Moritaka Suga ◽  
Kozo Kaibuchi ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
G Proteins ◽  
Calcium Influx ◽  
Kinase C ◽  
Rho Family ◽  
Small G Proteins

scholarly journals Atypical protein kinase C induces cell transformation by disrupting Hippo/Yap signaling

2015 ◽  
Vol 26 (20) ◽  
pp. 3578-3595 ◽  
Author(s):  
Andrew Archibald ◽  
Maia Al-Masri ◽  
Alyson Liew-Spilger ◽  
Luke McCaffrey
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Epithelial Cells ◽  
3D Culture ◽  
Cell Junctions ◽  
Nuclear Accumulation ◽  
Cell Phenotype ◽  
Atypical Protein Kinase C ◽  
Atypical Protein Kinase ◽  
Kinase C

Epithelial cells are major sites of malignant transformation. Atypical protein kinase C (aPKC) isoforms are overexpressed and activated in many cancer types. Using normal, highly polarized epithelial cells (MDCK and NMuMG), we report that aPKC gain of function overcomes contact inhibited growth and is sufficient for a transformed epithelial phenotype. In 2D cultures, aPKC induced cells to grow as stratified epithelia, whereas cells grew as solid spheres of nonpolarized cells in 3D culture. aPKC associated with Mst1/2, which uncoupled Mst1/2 from Lats1/2 and promoted nuclear accumulation of Yap1. Of importance, Yap1 was necessary for aPKC-mediated overgrowth but did not restore cell polarity defects, indicating that the two are separable events. In MDCK cells, Yap1 was sequestered to cell–cell junctions by Amot, and aPKC overexpression resulted in loss of Amot expression and a spindle-like cell phenotype. Reexpression of Amot was sufficient to restore an epithelial cobblestone appearance, Yap1 localization, and growth control. In contrast, the effect of aPKC on Hippo/Yap signaling and overgrowth in NMuMG cells was independent of Amot. Finally, increased expression of aPKC in human cancers strongly correlated with increased nuclear accumulation of Yap1, indicating that the effect of aPKC on transformed growth by deregulating Hippo/Yap1 signaling may be clinically relevant.

scholarly journals Minimally Modified LDL Upregulates Endothelin Type A Receptors in Rat Coronary Arterial Smooth Muscle Cells

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Jie Li ◽  
Lei Cao ◽  
Cang-Bao Xu ◽  
Jun-Jie Wang ◽  
Yong-Xiao Cao
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Smooth Muscle Cells ◽  
Coronary Arteries ◽  
Muscle Cells ◽  
Type A ◽  
Receptor Mrna ◽  
Kinase C ◽  
Arterial Smooth Muscle Cells

Minimally modified low-density lipoprotein (mmLDL) is a risk factor for cardiovascular disease. The present study investigated the effects of mmLDL on the expression of endothelin type A () receptors in coronary arteries. Rat coronary arteries were organ-cultured for 24 h. The contractile responses were recorded using a myographic system. receptor mRNA and protein expressions were determined using real-time PCR and western blotting, respectively. The results showed that organ-culturing in the presence of mmLDL enhanced the arterial contractility mediated by the receptor in a concentration-dependent and time-dependent manner. Culturing with mmLDL (10 μg/mL) for 24 h shifted the concentration-contractile curves toward the left significantly with increased of from control of and significantly increased receptor mRNA and protein levels. Inhibition of the protein kinase C, extracellular signal-related kinases 1 and 2 (ERK1/2), or NF-κB activities significantly attenuated the effects of mmLDL. The c-Jun N-terminal kinase inhibitor or the p38 pathway inhibitor, however, had no such effects. The results indicate that mmLDL upregulates the receptors in rat coronary arterial smooth muscle cells mainlyviaactivating protein kinase C, ERK1/2, and the downstream transcriptional factor, NF-κB.

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