ClC-3 is a candidate of the channel proteins mediating acid-activated chloride currents in nasopharyngeal carcinoma cells

2012 ◽  
Vol 303 (1) ◽  
pp. C14-C23 ◽  
Author(s):  
Liwei Wang ◽  
Wenbo Ma ◽  
Linyan Zhu ◽  
Dong Ye ◽  
Yuan Li ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Chloride Channel ◽  
Cell Function ◽  
Extracellular Ph ◽  
Carcinoma Cells ◽  
Chloride Current ◽  
Disulfonic Acid ◽  
Channel Blockers ◽  
Chloride Currents ◽  
Channel Proteins

Acid-activated chloride currents have been reported in several cell types and may play important roles in regulation of cell function. However, the molecular identities of the channels that mediate the currents are not defined. In this study, activation of the acid-induced chloride current and the possible candidates of the acid-activated chloride channel were investigated in human nasopharyngeal carcinoma cells (CNE-2Z). A chloride current was activated when extracellular pH was reduced to 6.6 from 7.4. However, a further decrease of extracellular pH to 5.8 inhibited the current. The current was weakly outward-rectified and was suppressed by hypertonicity-induced cell shrinkage and by the chloride channel blockers 5-nitro-2–3-phenylpropylamino benzoic acid (NPPB), tamoxifen, and 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid disodium salt hydrate (DIDS). The permeability sequence of the channel to anions was I− > Br− > Cl− > gluconate−. Among the ClC chloride channels, ClC-3 and ClC-7 were strongly expressed in CNE-2Z cells. Knockdown of ClC-3 expression with ClC-3 small interfering (si)RNA prevented the activation of the acid-induced current, but silence of ClC-7 expression with ClC-7 siRNA did not significantly affect the current. The results suggest that the chloride channel mediating the acid-induced chloride current was volume sensitive. ClC-3 is a candidate of the channel proteins that mediate or regulate the acid-activated chloride current in nasopharyngeal carcinoma cells.

Starvation-induced autophagy is up-regulated via ROS-mediated ClC-3 chloride channel activation in the nasopharyngeal carcinoma cell line CNE-2Z

2019 ◽  
Vol 476 (9) ◽  
pp. 1323-1333 ◽  
Author(s):  
Yanfang Zheng ◽  
Zhanru Chen ◽  
Zhuoyu Gu ◽  
Xiaoya Yang ◽  
Meisheng Yu ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Chloride Channel ◽  
Carcinoma Cell ◽  
Nutrient Deficiency ◽  
Chloride Current ◽  
Ros Generation ◽  
Channel Blockers ◽  
Biological Processes ◽  
Oxygen Species ◽  
Nasopharyngeal Carcinoma Cell

Abstract Nutrient deficiency develops frequently in nasopharyngeal carcinoma cell (CNE-2Z) due to the characteristics of aggregation and uncontrolled proliferation. Therefore, starvation can induce autophagy in these cells. Chloride channel 3 (ClC-3), a member of the chloride channel family, is involved in various biological processes. However, whether ClC-3 plays an important role in starvation-induced autophagy is unclear. In this study, Earle's balanced salt solution (EBSS) was used to induce autophagy in CNE-2Z cells. We found that autophagy and the chloride current induced by EBSS were inhibited by chloride channel blockers. ClC-3 knockdown inhibited the degradation of LC3-II and P62. Furthermore, when reactive oxygen species (ROS) generation was suppressed by antioxidant N-acetyl-l-cysteine (L-NAC) pretreatment, EBSS-induced autophagy was inhibited, and the chloride current was unable to be activated. Nevertheless, ClC-3 knockdown had little effect on ROS levels, indicating that ROS acted upstream of ClC-3 and that both ROS and ClC-3 participated in EBSS-induced autophagy regulation in CNE-2Z.

scholarly journals Hypotonicity activates a native chloride current in Xenopus oocytes.

1994 ◽  
Vol 103 (2) ◽  
pp. 153-179 ◽  
Author(s):  
M J Ackerman ◽  
K D Wickman ◽  
D E Clapham
Keyword(s):  
Xenopus Oocytes ◽  
Critical Role ◽  
Chloride Current ◽  
Signaling Cascades ◽  
Channel Blockers ◽  
Chloride Currents ◽  
Channel Proteins ◽  
Ion Channel Proteins

Xenopus oocytes are frequently utilized for in vivo expression of cellular proteins, especially ion channel proteins. A thorough understanding of the endogenous conductances and their regulation is paramount for proper characterization of expressed channel proteins. Here we detail a novel chloride current (ICl.swell) responsive to hypotonicity in Xenopus oocytes using the two-electrode voltage clamp technique. Reducing the extracellular osmolarity by 50% elicited a calcium-independent chloride current having an anion conductivity sequence identical with swelling-induced chloride currents observed in epithelial cells. The hypotonicity-activated current was blocked by chloride channel blockers, trivalent lanthanides, and nucleotides. G-protein, cAMP-PKA, and arachidonic acid signaling cascades were not involved in ICl.swell activation. ICl.swell is distinct from both stretch-activated nonselective cation channels and the calcium-activated chloride current in oocytes and may play a critical role in volume regulation in Xenopus oocytes.

The Effects of Chloride Channel Blockers on Platelet Cytoplasmic Free Calcium Concentration and Platelet Aggregation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3879-3879
Author(s):  
Songmei Yin ◽  
Xiaolin Chen ◽  
Danian Nie ◽  
Shuangfeng Xie ◽  
Liping Ma ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Calcium Channel ◽  
Calcium Channel Blockers ◽  
Chloride Channel ◽  
Calcium Concentration ◽  
Disulfonic Acid ◽  
Free Calcium ◽  
Channel Blockers ◽  
Free Calcium Concentration ◽  
Cytoplasmic Free Calcium

Abstract Objective To explore the effects of chloride channels on the regulations of platelet cytoplasmic free calcium concentration ([Ca2+]i) and platelet aggregation (PAG). Methods Platelet were separated freshly and then activated by thrombin; The chloride channel blockers 4,4′-diisothiocyano-2, 2′-disulfonic acid stilbene (DIDS) or niflumic acid (NFA), and calcium channel blockers 1-{β-[3-(4-methoxyphenyl)propoxy]- 4-methoxyphenethyl}- 1H - imidazole hydrochloride (SK&F96365) or Nifedipine were added to react with the activated platelets. The effects of each agent on platelet [Ca2+]i and PAG were detected. The combine effects and the interactions among chloride channel blockers (DIDS, NFA) and calcium channel blockers (SK&F96365, Nifedipine) were also investigated. Results Both DIDS and NFA [the concentration were12.5, 25, 50, 100 and 200μmol•L−1 respectively] could inhibit the PAG induced by thrombin (1U/ml) and the effect was dose-dependent. Compared with the control, they had no significant effects on resting [Ca2+]i. Compare with the control group, DIDS (100μmol•L−1), SK&F96365 (100μmol•L−1) and Nifedipine (100μmol•L−1) could significantly reduce the PAG, Ca2+ release and Ca2+ influx activated by thrombin in platelet (P<0.05). DIDS (100μmol•L−1) and SK&F96365 (100μmol•L−1) could enhance each other’s effect on reducing the PAG, Ca2+ release and Ca2+ influx (P<0.05). DIDS (100μmol•L−1) and Nifedipine (100μmol•L−1) could enhance each other’s effect on reducing Ca2+ release (P<0.05). NFA (100μmol•L−1) and SK&F96365 (100μmol•L−1) could weaken each other’s effect on Ca2+ release (P<0.05). NFA (100μmol•L−1) and Nifedipine (100μmol•L−1) could weaken each other’s effect on PAG, Ca2+ release and Ca2+ influx activated by thrombin in platelet (P<0.05). Conclusion The chloride channel blockers DIDS and NFA have no effect on the resting [Ca2+]i and the leak calcium influx of platelet. DIDS can inhibit the Ca2+ release, Ca2+ influx and PAG of platelet induced by thrombin, while NFA can only inhibit the Ca2+ release of platelet induced by thrombin. There are interactions between chloride channel blockers and calcium channel blockers in resting [Ca2+]i and PAG of platelet. The opening of chloride channel can influence the cellular calcium movement of platelet.

scholarly journals Gambogenic Acid Triggers Apoptosis of Human Nasopharyngeal Carcinoma CNE-2Z Cells through Activating Volume-Sensitive Outwardly Rectifying Chloride Channels

2018 ◽  
Author(s):  
Jingjing Su ◽  
Ting Xu ◽  
Genling Jiang ◽  
Mengru Liang ◽  
Hui Cheng ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Cell Membrane ◽  
Patch Clamp ◽  
Er Stress ◽  
Chloride Channel ◽  
Cell Apoptosis ◽  
Chloride Channels ◽  
Channel Blockers ◽  
Human Nasopharyngeal Carcinoma ◽  
Patch Clamp Method

Nasopharyngeal carcinoma (NPC) has not been thoroughly studied, and the pathogenesis of NPC is unclear. Scientists have neither discovered effective therapies nor achieved a desirable prognosis. Some studies have found that the regulation of intra- and extracellular ion channels hinges directly on cell apoptosis, and treatment with Gambogenic acid (GNA) brings changes to the volume-sensitive outwardly rectifying chloride (VSOR Cl-) current of CNE-2Z cells recorded by the patch clamp method. Nevertheless, rarely have any researchers probed into the relevance between this variation and the anti-tumor mechanism of GNA. This paper is suggested that GNA activates the VSOR Cl- current on the CNE-2Z cell membrane, and the activation of VSOR Cl- currents by GNA in CNE-2Z cells is blocked by the chloride channel blockers DIDS and DCPIB. GNA induces the down-regulation of GRP78 and up-regulation of ATF4 as well as chop proteins, which is evidence for the induction of CNE-2Z cell apoptosis, and this correlates with ER stress. GNA can activate the VSOR Cl- channel and lead to the occurrence of ER stress, thus inducing the apoptosis of CNE-2Z cells and inhibiting the proliferation of CNE-2Z cells.

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