Lysophosphatidic acid induced nuclear translocation of nuclear factor-κB in Panc-1 cells by mobilizing cytosolic free calcium

AIM: To clarify whether Lysophosphatidic acid (LPA) activates the nuclear translocation of nuclear factor-κB (NF-κB) in pancreatic cancer. METHODS: Panc-1, a human pancreatic cancer cell line, was used throughout the study. The expression of LPA receptors was confirmed by reverse-transcript polymerase chain reaction (RT-PCR). Cytosolic free calcium was measured by fluorescent calcium indicator fura-2, and the localization of NF-κB was visualized by immunofluorescent method with or without various agents, which effect cell signaling. RESULTS: Panc-1 expressed LPA receptors, LPA1, LPA2 and LPA3. LPA caused the elevation of cytosolic free calcium dose-dependently. LPA also caused the nuclear translocation of NF-κB. Cytosolic free calcium was attenuated by pertussis toxin (PTX) and U73122, an inhibitor of phospholipase C. The translocation of NF-κB was similarly attenuated by PTX and U73122, but phorbol ester, an activator of protein kinase C, alone did not translocate NF-κB. Furthermore, the translocation of NF-κB was completely blocked by Ca2+ chelator BAPTA-AM. Thapsigargin, an endoplasmic- reticulum Ca2+-ATPase pump inhibitor, also promoted the translocation of NF-κB. Staurosporine, a proteinkinase C inhibitor, attenuated translocation of NF-κB induced by LPA. CONCLUSION: These findings suggest that protein kinase C is activated endogenously in Panc-1, and protein kinase C is essential for activating NF-κB with cytosolic calcium and that LPA induces the nuclear translocation of NF-κB in Panc-1 by mobilizing cytosolic free calcium.

Effect of Lanthanum(Ⅲ) on Cytosolic Free Calcium in Isolated Rabbit Mature Osteoclasts

The effect of lanthanum （ Ⅲ ） （La^3 ＋ ） on cytosolic free calcium （ [ Ca^2 ＋ ] i ） in isolated rabbit mature osteoclasts was studied with the employment of fluo-3/AM as an intracellular calcium-sensitive fluorescent probe by using a confocal laser scanning microscope. La^3＋ does not alter basal [Ca^2＋ ]i levels and cell spread area at the concentration of 1.00 × 10^- 8 mol· L ^- 1. However, La^3 ＋ at higher concentrations （ 1. 00 × 10^ - 5 and 1.00 × 10^- 7 mol· L^- 1 ） decreases [ Ca^2 ＋ ] i levels and cell spread area, and greater decreases are observed for the higher concentrations of La^3 ＋ . Since [Ca^2 ＋ ]i affects cytoskeleton and the adhesion properties of osteoclasts, our results seem to suggest that La^3 ＋ inhibit bone resorption by decreasing [Ca^2＋]i in rabbit mature osteoclasts.

Effects of 3, 4-Dihydroxyacetophenone on Cytosolic Calcium in Pulmonary Artery Endothelial and Smooth Muscle Cells during Acute Hypoxia

Summary: The effects of 3, 4-Dihydroxyacetophenone (3, 4-DHAP) on cytosolic free calcium [Ca~2+ ]_i in pulmonary artery endothelia (PAECs) and smooth muscle cells (PASMCs) during acute hypoxia were studied. Porcine pulmonary artery endothelial and smooth muscle cells (PASMCs) were cultured primarily, and they were divided into 4 groups: groups incubated under normoxia or hypoxia and those with or without treatment with 3, 4-DHAP. The [Ca~2+ ]_i of both PAECs and PASMCs was measured by determining the fluorescence of fura 2 AM on spetrofluorometer. Our results showed that hypoxia caused significant elevation of [Ca~2+ ]_i, in both PAECs and PASMCs, 3, 4-DHAP could attenuate the hypoxic elevation of [Ca~2+ ]_i only in PASMCs but not in PAECs. It is concluded that 3, 4-DHAP decreases the hypoxic elevation of [Ca~2+ ]_i in PASMCs. This might contribute to its inhibitory effect on hypoxic pulmonary vasoconstriction.

ATP Evokes Calcium Transients in Single Pulmonary Artery Endothelial Cell in Primary Cultures

Effects of ATF on cytosclic free calcium ([Ca2+]i) in single porcine pulmonary artery endothelia cell were studied.Using a dual-wavelength excitation on microflurometry.it was found that ATP evoked a rapid transient in[Ca2+]i which was then followed by a maintained elevation of[Ca2+]i.The removal of extracellular Ca2+ abolished the maintained plateform, but exerted no obvious effect on the initial-transient.These results suggest that ATP stimulates both calcium release from intracellular calcium pool(s)and calcium influx across the Plasma membrane from extracellular space.

Changes of neuronal calcium channel following brain damage induced by injection of pertussis bacilli in rats

Objective: To explore changes of neuronal calcium channel following brain damage induced by injection of pertussis bacilli in rats, and to investigate the relationship between cytosolic free calcium concentration ([Ca 2+ ] i) in the synaptosome and Ca 2+ ATPase activities of mitochondria. Methods: The level of [Ca 2+ ] i in the synaptosome and Ca 2+ ATPase activities of mitochondria in the acute brain damage induced by injection of pertussis bacilli (PB) in rat was determined and nimodipine was administrated to show its effects on [Ca 2+ ] i in the synaptosome and on alteration of Ca 2+ ATPase activity in the mitochondria. Seventy three rats were randomly divided into four groups, ie, normal control group (Group A), sham operation control group (Group B), PB group (Group C) and nimodipine treatment group (Group D). Results: The level of [Ca 2+ ] i was significantly increased in the PB injected cerebral hemisphere in the Group C as compared with that in the Group A and the Group B at 30 minutes after injection of PB. The level of [Ca 2+ ] i was kept higher in the 4 hours and 24 hours subgroups after the injection in the Group C (P< 0.05 ). In contrast, the Ca 2+ ATPase activities were decreased remarkably among all of the subgroups in the Group C. Nimodipine, which was administered after injection of PB, could significantly decrease the [Ca 2+ ] i and increase the activity of Ca 2+ ATPase (P< 0.05 ). Conclusions: The neuronal calcium channel is opened after injection of PB. There is a negative correlation between activities of Ca 2+ ATPase and [Ca 2+ ] i. Nimodipine can reduce brain damage through stimulating the activities of Ca 2+ ATPase in the mitochondria, and decrease the level of [Ca 2+ ] i in the synaptosome. Treatment with nimodipine dramatically reduces the effects of brain damage induced by injection of PB.