title: Prostate cancer cells stimulated by calcium-mediated activation of protein kinase C undergo a refractory period before re-releasing calcium-bearing microvesicles.
abstract: MVs are released in response to several stress agents, in an attempt to prevent continued cellular damage. After an initial stimulus of prostate cancer cells with sublytic C5b-9 and activation of MV release through PKC, cells take at least 20 min to fully recover their ability to microvesiculate. This release of MVs through activation of sublytic C5b-9 was inhibited by the PKC inhibitor bisindoylmaleimide I but not the Rho kinase inhibitor, Y27632. After stimulus there is a rise of 79 nMs(-1) over 11 s, reaching a peak [Ca(2+)]i of 920 nM. The concentration of cytosolic calcium then falls steadily at 2.4 nMs(-1) over 109 s reaching baseline levels (50-100 nM) within 10-15 min. In PC3 cells the rate of release of MVs from stimulated cells also reaches a minimum within 10-15 min. Using fura-2 AM-loaded cells, upon stimulation, cells were found to release MVs with a concentration of intravesicular calcium estimated at ∼ 430 nM.
authors: Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, London, UK.
authors: Dan
authors: D
authors: Stratton
authors: Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, London, UK.
authors: Colin
authors: C
authors: Moore
authors: Dept. of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors: Lei
authors: L
authors: Zheng
authors: University College London School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK.
authors: Sigrun
authors: S
authors: Lange
authors: Cellular and Molecular Immunology Research Centre, School of Human Sciences, London Metropolitan University, London, UK. Electronic address: j.inal@londonmet.ac.uk.
authors: Jameel
authors: J
authors: Inal
mesh_terms: D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D045744:Cell Line, Tumor; D015938:Complement Membrane Attack Complex / Q000008:administration & dosage; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*
chemical_list: D015938:Complement Membrane Attack Complex; D011493:Protein Kinase C; D002118:Calcium
keywords: Intravesicular calcium; Microvesicles; Refractory period; Sublytic C5b-9