Action of the natural compound gomisin a on Ca2+ movement in human prostate cancer cells.

Gomisin A is a dietary lignan compound isolated from the fruit of Schisandra chinensis and has many pharmacological properties, including hepato-protective, anti-diabetic, and anti-oxidative activities. However, the benefit of gomisin A is still not well understood. The action of gomisin A is diverse. However, the effect of gomisin A on Ca2+ signaling in prostate cancer cells is unknown. Ca2+ is a pivotal second envoy that triggers and regulates cellular processes such as apoptosis, fertilization, energy transduction, secretion, and protein activation. The goal of this study was to explore the action of gomisin A on [Ca2+]i and cytotoxicity in PC3 prostate cancer cells. Gomisin A at 100-200 µM provoked [Ca2+]i raises. 20% of the response was reduced by removing external Ca2+. The Ca2+ influx provoked by gomisin A was suppressed by 20% by store-caused Ca2+ entry suppressors: econazole, SKF96365, nifedipine; also by phorbol 12-myristate 13 acetate and GF109203X. Without external Ca2+, gomisin A-caused [Ca2+]i raises were abolished by thapsigargin. In contrast, gomisin A suppressed the [Ca2+]i raises caused by thapsigargin. U73122 fell short to change gomisin A-caused [Ca2+]i responses. Gomisin A (20-100 µM) elicited cytotoxicity in a dose-associated fashion. Blockade of [Ca2+] elevations with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxy methyl failed to inhibit cytotoxicity of gomisin A. Collectively, gomisin A evoked [Ca2+]i raises and provoked cytotoxicity in a Ca2+-dissociated fashion in prostate cancer cells.

Hydroxytyrosol [2-(3,4-dihydroxyphenyl)-ethanol], a natural phenolic compound found in the olive, alters Ca2+ signaling and viability in human HepG2 hepatoma cells.

Hepatotoma is the leading type of primary liver cancer in adults and third cause of death in the world. Hydroxytyrosol is a natural phenol existing in olive (Olea europaea L.). Hydroxytyrosol is the chief ingredient of olive oil, which was early deemed to be the most robust antioxidant in olive oil. Hydroxytyrosol is known to inhibit various types of cancer by different methods. This study was aimed to delineate the action of hydroxytyrosol on viability and [Ca2+]i in HepG2 hepatoma cells. Fura-2 was used to detect [Ca2+]i, and WST-1 assays were applied to explore cell cytotoxicity. Hydroxytyrosol elicited [Ca2+]i raises. Eliminating external Ca2+ diminished the Ca2+ signal by 30%. Hydroxytyrosol-evoked Ca2+ influx was diminished by 20% by three inhibitors of store-operated Ca2+ channels and by a protein kinase C activator and an inhibitor. In the absence of Ca2+, thapsigargin eradicated hydroxytyrosol-provoked [Ca2+]i raises. Suppression of phospholipase C (PLC) with U73122, a PLC inhibitor, did not inhibit hydroxytyrosol-elicited [Ca2+]i raises. Hydroxytyrosol reduced cell viability. This cytotoxic action was not reversed by preincubation with BAPTA/AM, a cytosolic Ca2+ binder. In sum, in HepG2 hepatoma cells, hydroxytyrosol elicited [Ca2+]i raises by provoking PLC-unrelated discharge of Ca2+ from ER and Ca2+ influx through PKC-sensitive store-operated Ca2+ entry. In addition, hydroxytyrosol elicited Ca2+-dissociated cytotoxicity.

Mechanisms underlying the effect of an oral antihyperglycaemic agent glyburide on calcium ion (Ca2+ ) movement and its related cytotoxicity in prostate cancer cells.

Glyburide is an agent commonly used to treat type 2 diabetes and also affects various physiological responses in different models. However, the effect of glyburide on Ca2+ movement and its related cytotoxicity in prostate cancer cells is unclear. This study examined whether glyburide altered Ca2+ signalling and viability in PC3 human prostate cancer cells and investigated those underlying mechanisms. Intracellular Ca2+ concentrations ([Ca2+ ]i ) in suspended cells were measured by using the fluorescent Ca2+ -sensitive dye fura-2. Cell viability was examined by WST-1 assay. Glyburide at concentrations of 100-1000 µM induced [Ca2+ ]i rises. Ca2+ removal reduced the signal by approximately 60%. In Ca2+ -containing medium, glyburide-induced Ca2+ entry was inhibited by 60% by protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate, PMA) and inhibitor (GF109203X), and modulators of store-operated Ca2+ channels (nifedipine, econazole and SKF96365). Furthermore, glyburide induced Mn2+ influx suggesting of Ca2+ entry. In Ca2+ -free medium, inhibition of phospholipase C (PLC) with U73122 significantly inhibited glyburide-induced [Ca2+ ]i rises. Treatment with the endoplasmic reticulum (ER) Ca2+ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished glyburide-evoked [Ca2+ ]i rises. Conversely, treatment with glyburide abolished BHQ-evoked [Ca2+ ]i rises. Glyburide at 100-500 µM decreased cell viability, which was not reversed by pretreatment with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM). Together, in PC3 cells, glyburide induced [Ca2+ ]i rises by Ca2+ entry via PKC-sensitive store-operated Ca2+ channels and Ca2+ release from the ER in a PLC-dependent manner. Glyburide also caused Ca2+ -independent cell death. This study suggests that glyburide could serve as a potential agent for treatment of prostate cancer.

Exploring the impact of a naturally occurring sapogenin diosgenin on underlying mechanisms of Ca2+ movement and cytotoxicity in human prostate cancer cells.

Literature has shown that diosgenin, a naturally occurring sapogenin, inducedcytotoxic effects in many cancer models. This study investigated the effect of diosgenin on intracellular Ca2+ concentration ([Ca2+ ]i) and cytotoxicity in PC3 human prostate cancer cells. Diosgenin (250-1000 µM) caused [Ca2+ ]i rises which was reduced by Ca2+ removal. Treatment with thapsigargin eliminated diosgenin-induced [Ca2+ ]i increases. In contrast, incubation with diosgeninabolished thapsigargin-caused [Ca2+ ]i increases. Suppression of phospholipase C with U73122 eliminated diosgenin-caused [Ca2+ ]i increases. Diosgenin evoked Mn2+ influx suggesting that diosgenin induced Ca2+ entry. Diosgenin-induced Ca2+ influx was suppressed by PMA, GF109203X, and nifedipine, econazole, or SKF96365. Diosgenin (250-600 µM) concentration-dependently decreased cell viability. However, diosgenin-induced cytotoxicity was not reversed by chelation of cytosolic Ca2+ with BAPTA/AM. Together, diosgenin evoked [Ca2+ ]i increases via Ca2+ release and Ca2+ influx, and caused Ca2+ -non-associated deathin PC3 cells. These findings reveal a newtherapeutic potential of diosgenin for human prostate cancer.

Exploration of thioridazine-induced Ca2+ signaling and non-Ca2+-triggered cell death in HepG2 human hepatocellular carcinoma cells.

Thioridazine, belonging to first-generation antipsychotic drugs, is a prescription used to treat schizophrenia. However, the effect of thioridazine on intracellular Ca2+ concentration ([Ca2+]i) and viability in human liver cancer cells is unclear. This study examined whether thioridazine altered Ca2+ signaling and viability in HepG2 human hepatocellular carcinoma cells. Ca2+ concentrations in suspended cells were measured using the fluorescent Ca2+-sensitive dye fura-2. Cell viability was examined by WST-1 assay. Thioridazine at concentrations of 25-100 µM induced [Ca2+]i rises. Ca2+ removal reduced the signal by 20%. Thioridazine (100 µM) induced Mn2+ influx suggesting of Ca2+ entry. Thioridazine-induced Ca2+ entry was inhibited by 20% by protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate) and inhibitor (GF109203X) and by three inhibitors of store-operated Ca2+ channels: nifedipine, econazole, and SKF96365. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) abolished thioridazine-evoked [Ca2+]i rises. On the other hand, thioridazine preincubation completely inhibited the [Ca2+]i rises induced by TG. Furthermore, U73122 totally suppressed the [Ca2+]i rises induced by thioridazine via inhibition of phospholipase C (PLC). Regarding cytotoxicity, at 30-80 µM, thioridazine reduced cell viability in a concentration-dependent fashion. This cytotoxicity was not prevented by preincubation with 1,2-bis (2-aminophenoxy) ethane-N, N, N', N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM) (a Ca2+ chelator). To conclude, thioridazine caused concentration-dependent [Ca2+]i rises in HepG2 human hepatoma cells by inducing Ca2+ release from the endoplasmic reticulum via PLC-associated pathways and Ca2+ influx from extracellular medium through PKC-sensitive store-operated Ca2+ entry. In addition, thioridazine induced cytotoxicity in a Ca2+-independent manner.

Investigation of effect of tectorigenin (O-methylated isoflavone) on Ca2+ signal transduction and cytotoxic responses in canine renal tubular cells.

Tectorigenin, a traditional Chinese medicine, is isolated from the flower of plants such as Pueraria thomsonii Benth. It is an O-methylated isoflavone, a type of flavonoid. Previous studies have shown that tectorigenin evoked various physiological responses in different models, but the effect of tectorigenin on cytosolic-free Ca2+ levels ([Ca2+]i) and cytotoxicity in renal tubular cells is unknown. Our research explored if tectorigenin changed Ca2+ signal transduction and viability in Madin-Darby Canine Kidney (MDCK) renal tubular cells. [Ca2+]iin suspended cells were measured by applying the fluorescent Ca2+-sensitive probe fura-2. Viability was explored by using water-soluble tetrazolium-1 as a fluorescent dye. Tectorigenin at concentrations of 5-50 µM induced [Ca2+]irises. Ca2+ removal reduced the signal by approximately 20%. Tectorigenin (50 µM) induced Mn2+ influx suggesting of Ca2+ entry. Tectorigenin-induced Ca2+ entry was inhibited by 10% by three inhibitors of store-operated Ca2+ channels, namely, nifedipine, econazole, and SKF96365. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin inhibited 83% of tectorigenin-evoked [Ca2+]irises. Conversely, treatment with tectorigenin abolished thapsigargin-evoked [Ca2+]irises. Inhibition of phospholipase C with U73122 inhibited 50% of tectorigenin-induced [Ca2+]irises. Tectorigenin at concentrations between 10 and 60 µM killed cells in a concentration-dependent fashion. Chelation of cytosolic Ca2+ with 1,2-bis (2-aminophenoxy)ethane-N, N, N', N'-tetraacetic acid/acetoxy methyl did not reverse tectorigenin's cytotoxicity. Our data suggest that, in MDCK cells, tectorigenin evoked [Ca2+]irises and induced cell death that was not associated with [Ca2+]irises. Therefore, tectorigenin may be a Ca2+-independent cytotoxic agent for kidney cells.

The exploration of effect of terfenadine on Ca2+ signaling in renal tubular cells.

Terfenadine, an antihistamine used for the treatment of allergic conditions, affected Ca2+-related physiological responses in various models. However, the effect of terfenadine on cytosolic free Ca2+ levels ([Ca2+]i) and its related physiology in renal tubular cells is unknown. This study examined whether terfenadine altered Ca2+ signaling and caused cytotoxicity in Madin-Darby canine kidney (MDCK) renal tubular cells. The Ca2+-sensitive fluorescent dye fura-2 was used to measure [Ca2+]i. Cell viability was measured by the fluorescent reagent 4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] water soluble tetrazolium-1 (WST-1) assay. Terfenadine at concentrations of 100-1000 µM induced [Ca2+]i rises concentration dependently. The response was reduced by approximately 35% by removing extracellular Ca2+. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) partly inhibited terfenadine-evoked [Ca2+]i rises. Conversely, treatment with terfenadine abolished BHQ-evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 inhibited 95% of terfenadine-induced Ca2+ release. Terfenadine-induced Ca2+ entry was supported by Mn2+-caused quenching of fura-2 fluorescence. Terfenadine-induced Ca2+ entry was partly inhibited by an activator of protein kinase C (PKC), phorbol 12-myristate 13 acetate (PMA) and by three modulators of store-operated Ca2+ channels (nifedipine, econazole, and SKF96365). Terfenadine at 200-300 µM decreased cell viability, which was not reversed by pretreatment with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM). Together, in MDCK cells, terfenadine induced [Ca2+]i rises by evoking PLC-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via PKC-sensitive store-operated Ca2+ entry. Furthermore, terfenadine caused cell death that was not triggered by preceding [Ca2+]i rises.

Uncovering malathion (an organophosphate insecticide) action on Ca2+ signal transduction and investigating the effects of BAPTA-AM (a cell-permeant Ca2+ chelator) on protective responses in glial cells.

Malathion, one of commonly used organophosphate insecticides, has a wide range of toxic actions in different models. However, the effect of this compound on Ca2+ homeostasis and its related cytotoxicity in glial cells is elusive. This study examined whether malathion evoked intracellular Ca2+ concentration ([Ca2+]i) rises and established the relationship between Ca2+ signaling and cytotoxicity in normal human astrocytes, rat astrocytes and human glioblastoma cells. The data show that malathion induced concentration-dependent [Ca2+]i rises in Gibco® Human Astrocytes (GHA cells), but not in DI TNC1 normal rat astrocytes and DBTRG-05MG human glioblastoma cells. In GHA cells, this Ca2+ signal response was reduced by removing extracellular Ca2+. In Ca2+-free medium, pretreatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin abolished malathion-induced [Ca2+]i rises. Conversely, incubation with malathion abolished thapsigargin-induced [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 also blocked malathion-induced [Ca2+]i rises. In Ca2+-containing medium, malathion-induced [Ca2+]i rises was inhibited by store-operated Ca2+ channel blockers (2-APB, econazole or SKF96365) and the protein kinase C (PKC) inhibitor GF109203X. Malathion (5-25 µM) concentration-dependently caused cytotoxicity in GHA, DI TNC1 and DBTRG-05MG cells. This cytotoxic effect was partially prevented by prechelating cytosolic Ca2+ with BAPTA-AM (a selective Ca2+ chelator) only in GHA cells. Together, in GHA but not in DI TNC1 and DBTRG-05MG cells, malathion induced [Ca2+]i rises by inducing PLC-dependent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via PKC-sensitive store-operated Ca2+ channels. Furthermore, malathion induced Ca2+-associated cytotoxicity, suggesting that Ca2+ chelating may have a protective effect on malathion-induced cytotoxicity in normal human astrocytes.

Action of chlorzoxazone on Ca2+movement and viability in human oral cancer cells.

Chlorzoxazone is a skeletal muscle relaxant. However, the effect of chlorzoxazone on intracellular Ca2+ concentrations ([Ca2+]i) in oral cancer cells is unclear. This study examined whether chlorzoxazone altered Ca2+ signaling and cell viability in OC2 human oral cancer cells. [Ca2+]iin suspended cells was measured using the fluorescent Ca2+-sensitive dye fura-2. Cell viability was examined by water-soluble tetrazolium-1 assay. Chlorzoxazone (250-1000 µM) induced [Ca2+]irises in a concentration-dependent manner. Ca2+ removal reduced the signal by approximately 50%. Mn2+ has been shown to enter cells through similar mechanisms as Ca2+ but quenches fura-2 fluorescence at all excitation wavelengths. Chlorzoxazone (1000 µM) induced Mn2+ influx, suggesting that Ca2+ entry occurred. Chlorzoxazone-induced Ca2+ entry was inhibited by 20% by inhibitors of store-operated Ca2+ channels and protein kinase C (PKC) modulators. In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (TG) inhibited chlorzoxazone-evoked [Ca2+]irises by 88%. Conversely, treatment with chlorzoxazone-suppressed TG-evoked [Ca2+]irises 75%. Chlorzoxazone induced [Ca2+]irises by exclusively releasing Ca2+ from the endoplasmic reticulum. Inhibition of phospholipase C (PLC) with U73122 did not alter chlorzoxazone-induced [Ca2+]irises. PLC activity was not involved in chlorzoxazone-evoked [Ca2+]irises. Chlorzoxazone at 200-700 µM decreased cell viability, which was not reversed by pretreatment with Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxy methyl. In sum, in OC2 cells, chlorzoxazone induced [Ca2+]irises by evoking PLC-independent Ca2+ release from the endoplasmic reticulum and Ca2+ entry via PKC-sensitive store-operated Ca2+ entry. Chlorzoxazone also caused Ca2+-independent cell death. Since [Ca2+]irises play a triggering or modulatory role in numerous cellular phenomena, the effect of chlorzoxazone on [Ca2+]iand cell viability should be taken into account in other in vitro studies.

Effects of timolol on Ca2+ handling and viability in human prostate cancer cells.

Timolol is a medication used widely to treat glaucoma. Regarding Ca2+ signaling, timolol was shown to modulate Ca2+-related physiology in various cell types, however, the effect of timolol on Ca2+ homeostasis and cell viability has not been explored in human prostate cancer cells. The aim of this study was to explore the effect of timolol on intracellular Ca2+ concentrations ([Ca2+]i) and viability in PC3 human prostate cancer cells. Timolol at concentrations of 100-1000 µM induced [Ca2+]i rises. The Ca2+ signal in Ca2+-containing medium was reduced by removal of extracellular Ca2+ by approximately 75%. Timolol (1000 µM) induced Mn2+ influx suggesting of Ca2+ entry. Timolol-induced Ca2+ entry was partially inhibited by three inhibitors of store-operated Ca2+ channels: nifedipine, econoazole and SKF96365, and by a protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate [PMA]) or an inhibitor (GF109203X). In Ca2+-free medium, treatment with the endoplasmic reticulum Ca2+ pump inhibitor thapsigargin abolished timolol-evoked [Ca2+]i rises. Conversely, treatment with timolol abolished thapsigargin-evoked [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 abolished timolol-induced [Ca2+]i rises. Timolol at concentrations between 200 and 600 µM killed cells in a concentration-dependent fashion. Chelation of cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/AM (BAPTA/AM) did not reverse cytotoxicity of timolol. Together, in PC3 cells, timolol induced [Ca2+]i rises by evoking Ca2+release from the endoplasmic reticulum in a PLC-dependent manner, and Ca2+ influx via PKC-regulated store-operated Ca2+ entry. Timolol also caused cell death that was not linked to preceding [Ca2+]i rises.

Effect of Captopril on Ca²âº Homeostasis and Cell Viability in Human Hepatoma Cells.

Captopril, an angiotensin-converting enzyme (ACE) inhibitor, induced different Ca²âº signaling responses in various cell models. However, the effect of captopril on Ca²âº homeostasis and cell viability in hepatoma cells is unknown. This study examined whether captopril altered Ca²âº homeostasis and viability in HepG2 human hepatoma cells. Intracellular Ca²âº concentrations in suspended cells were monitored by using the fluorescent Ca²âº-sensitive dye fura-2. Cell viability was examined by using 4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] water soluble tetrazolium-1 (WST-1). Captopril at concentrations of 500-3000 µM induced [Ca²âº]i rises in a concentration-dependent manner. Ca²âº removal reduced the signal by approximately 15%. Mn²âº has been shown to enter cells through similar mechanisms as Ca²âº but quenches fura-2 fluorescence at all excitation wavelengths. Captopril (3000 µM)-induced Mn²âº influx indirectly suggested that captopril evoked Ca²âº entry. Captopril-induced Ca²âº entry was inhibited by 15% by a protein kinase C (PKC) activator (phorbol 12-myristate 13 acetate, PMA) and an inhibitor (GF109203X) and three inhibitors of store-operated Ca²âº channels: nifedipine, econazole and SKF96365. In Ca²âº-free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished captopril-evoked [Ca²âº]i rises. Conversely, treatment with captopril abolished BHQ-evoked [Ca²âº]i rises. Inhibition of phospholipase C (PLC) with U73122 inhibited 70% of captopril-induced [Ca²âº]i rises. Captopril at concentrations between 150-550 µM killed cells in a concentration-dependent fashion. Chelation of cytosolic Ca²âº with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/AM (BAPTA/AM) did not reverse captopril's cytotoxicity. Together, in HepG2 human hepatoma cells, captopril induced [Ca²âº]i rises and caused cell death that was not triggered by preceding [Ca²âº]i rises.

Exploration of Niflumic Acid's Action on Ca²âº Movement and Cell Viability in Human Osteosarcoma Cells.

Niflumic acid, a drug used for joint and muscular pain, affected Ca²âº signaling in different models. However, the effect of niflumic acid on Ca²âº homeostasis and Ca²âº-related physiology in human osteosarcoma cells is unknown. This study examined the effect of niflumic acid on cytosolic free Ca²âº concentrations ([Ca²âº]i) in MG63 human osteosarcoma cells. Intracellular Ca²âº concentrations in suspended cells were monitored by using the fluorescent Ca²âº-sensitive dye fura- 2. Cell viability was examined by using 4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio- 1,3-benzene disulfonate] water soluble tetrazolium-1 (WST-1). In MG63 cells, niflumic acid at concentrations of 250-750 µM evoked [Ca²âº]i rises concentration-dependently. Niflumic acid-evoked Ca²âº entry was confirmed by Mn²âº-induced quenching of fura-2 fluorescence. This entry was inhibited by nifedipine, econazole, SKF96365, the protein kinase C (PKC) activator phorbol 12-myristate 13 acetate (PMA), but was not affected by the PKC inhibitor GF109203X. In Ca²âº- free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor thapsigargin (TG) inhibited niflumic acid-evoked [Ca²âº]i rises. Conversely, treatment with niflumic acid abolished TG-evoked [Ca²âº]i rises. Inhibition of phospholipase C (PLC) with U73122 also partly reduced niflumic acid-evoked [Ca²âº]i rises. Niflumic acid killed cells at 200-500 µM in a concentration-dependent fashion. Chelating cytosolic Ca²âº with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/ AM (BAPTA/AM) did not reverse niflumic acid-induced cytotoxicity. Collectively, our data suggest that in MG63 cells, niflumic acid induced [Ca²âº]i rises by evoking PLC-dependent Ca²âº release from the endoplasmic reticulum, and Ca²âº entry via PKC-sensitive store-operated Ca²âº entry. Niflumic acid also induced Ca²âº-independent cell death.

The investigation of minoxidil-induced [Ca2+]i rises and non-Ca2+-triggered cell death in PC3 human prostate cancer cells.

Minoxidil is clinically used to prevent hair loss. However, its effect on Ca2+ homeostasis in prostate cancer cells is unclear. This study explored the effect of minoxidil on cytosolic-free Ca2+ levels ([Ca2+]i) and cell viability in PC3 human prostate cancer cells. Minoxidil at concentrations between 200 and 800 µM evoked [Ca2+]i rises in a concentration-dependent manner. This Ca2+ signal was inhibited by 60% by removal of extracellular Ca2+. Minoxidil-induced Ca2+ influx was confirmed by Mn2+-induced quench of fura-2 fluorescence. Pre-treatment with the protein kinase C (PKC) inhibitor GF109203X, PKC activator phorbol 12-myristate 13 acetate (PMA), nifedipine and SKF96365 inhibited minoxidil-induced Ca2+ signal in Ca2+ containing medium by 60%. Treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5-ditert-butylhydroquinone (BHQ) in Ca2+-free medium abolished minoxidil-induced [Ca2+]i rises. Conversely, treatment with minoxidil abolished BHQ-induced [Ca2+]i rises. Inhibition of phospholipase C (PLC) with U73122 abolished minoxidil-evoked [Ca2+]i rises. Overnight treatment with minoxidil killed cells at concentrations of 200-600 µM in a concentration-dependent fashion. Chelation of cytosolic Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/AM (BAPTA/AM) did not prevent minoxidil's cytotoxicity. Together, in PC3 cells, minoxidil induced [Ca2+]i rises that involved Ca2+ entry through PKC-regulated store-operated Ca2+ channels and PLC-dependent Ca2+ release from the endoplasmic reticulum. Minoxidil-induced cytotoxicity in a Ca2+-independent manner.

Effect of tetramethylpyrazine (TMP) on Ca2+ signal transduction and cell viability in a model of renal tubular cells.

Tetramethylpyrazine (TMP) is a compound purified from herb. Its effect on Ca2+ concentrations ([Ca2+ ]i ) in renal cells is unclear. This study examined whether TMP altered Ca2+ signaling in Madin-Darby canine kidney (MDCK) cells. TMP at 100-800 µM induced [Ca2+ ]i rises, which were reduced by Ca2+ removal. TMP induced Mn2+ influx implicating Ca2+ entry. TMP-induced Ca2+ entry was inhibited by 30% by modulators of protein kinase C (PKC) and store-operated Ca2+ channels. Treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) inhibited 93% of TMP-evoked [Ca2+ ]i rises. Treatment with TMP abolished BHQ-evoked [Ca2+ ]i rises. Inhibition of phospholipase C (PLC) abolished TMP-induced responses. TMP at 200-1000 µM decreased viability, which was not reversed by pretreatment with the Ca2+  chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester. Together, in MDCK cells, TMP induced [Ca2+ ]i rises by evoking PLC-dependent Ca2+ release from endoplasmic reticulum and Ca2+ entry via PKC-sensitive store-operated Ca2+ entry. TMP also caused Ca2+ -independent cell death.

Evaluation of cytotoxicity of propofol and its related mechanism in glioblastoma cells and astrocytes.

Propofol (2,6-diisopropylphenol), one of the extensively and commonly used anesthetic agents, has been shown to affect the biological behavior of various models. Previous researches have shown that propofol-induced cytotoxicity might cause anticancer effect in different cells. However, the mechanisms underlying the effect of propofol on cytotoxicity is still elusive in human glioblastoma cells. The aims of this study were to evaluate effects of propofol on cytotoxicity, cell cycle distribution and ROS production, and establish the relationship between oxidative stress and cytotoxicity in GBM 8401 human glioblastoma cells and DI TNC1 rat astrocytes. Propofol (20-30 µM) concentration-dependently induced cytotoxicity, cell cycle arrest, and increased ROS production in GBM 8401 cells but not in DI TNC1 cells. In GBM 8401 cells, propofol induced G2/M phase cell arrest, which affected the CDK1, cyclin B1, p53, and p21 protein expression levels. Furthermore, propofol induced oxygen stresses by increasing O2- and H2 O2 levels but treatment with the antioxidant N-acetylcysteine (NAC) partially reversed propofol-regulated antioxidative enzyme levels (superoxide dismutase, catalase, and glutathione peroxidase). Most significantly, propofol induced apoptotic effects by decreasing Bcl-2 but increasing Bax, cleaved caspase-9/caspase-3 levels, which were partially reversed by NAC. Moreover, the pancaspase inhibitor Z-VAD-FMK also partially prevented propofol-induced apoptosis. Together, in GBM 8401 cells but not in DI TNC1 cells, propofol activated ROS-associated apoptosis that involved cell cycle arrest and caspase activation. These findings indicate that propofol not only can be an anesthetic agent which reduces pain but also has the potential to be used for the treatment of human glioblastoma.

Effect of Carvacrol on Ca²âº Movement and Viability in PC3 Human Prostate Cancer Cells.

Carvacrol, a monoterpenic phenol compound, has been shown to possess various biological effects in different models. However, the effect of carvacrol on intracellular Ca²âº and its related physiology in human prostate cancer is unknown. This study explored the effect of carvacrol on cytosolic free Ca²âº levels ([Ca²âº]i) and viability in PC3 human prostate cancer cells. Fura-2, a Ca²âº- sensitive fluorescent dye, was used to assess [Ca²âº]i. Cell viability was measured by the detecting reagent WST-1. Carvacrol at concentrations of 200-800 µM caused [Ca²âº]i rises in a concentration-dependent manner. Removal of extracellular Ca²âº reduced carvacrol's effect by approximately 60%. Carvacrol-induced Ca²âº entry was confirmed by Mn²âº entry-induced quench of fura-2 fluorescence, and was inhibited by approximately 30% by nifedipine, econazole, SKF96365, and the protein kinase C (PKC) inhibitor GF109203X. In Ca²âº-free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor thapsigargin (TG) abolished carvacrol-induced [Ca²âº]i rises. Treatment with carvacrol also abolished TG-induced [Ca²âº]i rises. Carvacrol-induced Ca²âº release from the endoplasmic reticulum was abolished by inhibition of phospholipase C (PLC). Carvacrol killed cells at concentrations of 200-600 µM in a concentration-dependent fashion. Chelating cytosolic Ca²âº with BAPTA/AM did not prevent carvacrol's cytotoxicity. Together, in PC3 cells, carvacrol induced [Ca²âº]i rises by inducing PLC-dependent Ca²âº release from the endoplasmic reticulum and Ca²âº entry via PKC-sensitive store-operated Ca²âº channels and other unknown channels. Carvacrol also induced Ca²âº-dissociated cell death.

Effect of Protriptyline on [Ca²âº]i and Viability in MDCK Renal Tubular Cells.

Protriptyline has been used as an antidepressant. Clinically it has been prescribed in the auxiliary treatment of cancer patients. However, its effect on Ca²âº signaling and related physiology is unknown in renal cells. This study examined the effect of protriptyline on cytosolic free Ca²âº concentrations ([Ca²âº]i) and viability in Madin-Darby canine kidney (MDCK) tubular cells. Protriptyline induced [Ca²âº]i rises concentration-dependently. The response was reduced by 20% by removing extracellular Ca²âº. Protriptyline-induced Ca²âº entry was not altered by protein kinase C (PKC) activity but was inhibited by 20% by three modulators of store-operated Ca²âº channels: nifedipine, econazole and SKF96365. In Ca²âº-free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor 2,5- di-tert-butylhydroquinone (BHQ) or thapsigargin partially inhibited protriptyline-evoked [Ca²âº]i rises. Conversely, treatment with protriptyline inhibited partially BHQ or thapsigargin-evoked [Ca²âº]i rises. Inhibition of phospholipase C (PLC) with U73122 did not change protriptyline-induced [Ca²âº]i rises. Protriptyline at 5-200 µM decreased cell viability, which was not reversed by pretreatment with the Ca²âº chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/ AM). Together, in MDCK cells, protriptyline induced [Ca²âº]i rises by evoking PLC-independent Ca²âº release from the endoplasmic reticulum and other unknown stores, and Ca²âº entry via PKCinsensitive store-operated Ca²âº entry. Protriptyline also caused Ca²âº-independent cell death.

Effect of Methoxsalen on Ca²âº Homeostasis and Viability in Human Osteosarcoma Cells.

Methoxsalen is a natural compound found in many seed plants. The effect of methoxsalen on Ca²âº- related physiology in human osteosarcoma is unclear. This study investigated the effect of methoxsalen on cytosolic free Ca²âº concentrations ([Ca²âº]i) in MG63 human osteosarcoma cells. Methoxsalen induced [Ca²âº]i rises concentration-dependently. Methoxsalen-induced Ca²âº entry was confirmed by Mn²âº-induced quench of fura-2 fluorescence. This Ca²âº entry was suppressed by nifedipine, econazole, and SKF96365. In Ca²âº-free medium, incubation with the endoplasmic reticulum Ca²âº pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) inhibited methoxsalen-evoked [Ca²âº]i rises by 96%. In contrast, incubation with methoxsalen abolished BHQ-evoked [Ca²âº]i rises. Inhibition of phospholipase C (PLC) with U73122 abolished methoxsalen-induced [Ca²âº]i rises. Methoxsalen was cytotoxic at 300-700 µM in a concentration-dependent fashion. Chelating cytosolic Ca²âº with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/acetoxymethyl ester (BAPTA/AM) did not prevent methoxsalen-induced cytotoxicity. Collectively, our data suggest that in MG63 cells, methoxsalen induced [Ca²âº]i rises by evoking PLC-dependent Ca²âº release from the endoplasmic reticulum, and Ca²âº entry via store-operated Ca²âº entry. Methoxsalen also induced Ca²âº- disassociated cell death.

Effect of thymol on Ca²âº homeostasis and viability in PC3 human prostate cancer cells.

Thymol is a phenolic compound that affects physiology in different cell models. However, whether thymol affects Ca²âº homeostasis in prostate cancer cells is unknown. The action of this compound on cytosolic Ca²âº concentrations ([Ca²âº]i) and viability in PC3 human prostate cancer cells was explored. The results show that thymol at concentrations of 100-1500 µM caused [Ca²âº]i rises in a concentration-dependent manner. Removal of extracellular Ca²âº reduced thymol's effect by approximately 80%. Thymol-induced Ca²âº entry was confirmed by Mn²âº entry-induced quench of fura-2 fluorescence, and was inhibited by approximately 30% by Ca²âº entry modulators (nifedipine, econazole, SKF96365), and the protein kinase C (PKC) inhibitor GF109203X. In Ca²âº-free medium, treatment with the endoplasmic reticulum Ca²âº pump inhibitor thapsigargin abolished thymol-induced [Ca²âº]i rises. Treatment with thymol also abolished thapsigargin-induced [Ca²âº]i rises. Thymol-induced Ca²âº release from the endoplasmic reticulum was abolished by the phospholipase C (PLC) inhibitor U73122. Thymol at 100-900 µM decreased cell viability, which was not reversed by pretreatment with the Ca²âº chelator 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM). Together, in PC3 cells, thymol induced [Ca²âº]i rises by inducing PLC-dependent Ca²âº release from the endoplasmic reticulum and Ca²âº entry via PKC-sensitive store-operated Ca²âº channels and other unknown channels. Thymol also induced Ca²âº-dissociated cell death.

Esculetin, a natural coumarin compound, evokes Ca(2+) movement and activation of Ca(2+)-associated mitochondrial apoptotic pathways that involved cell cycle arrest in ZR-75-1 human breast cancer cells.

Esculetin (6,7-dihydroxycoumarin), a derivative of coumarin compound, is found in traditional medicinal herbs. It has been shown that esculetin triggers diverse cellular signal transduction pathways leading to regulation of physiology in different models. However, whether esculetin affects Ca(2+) homeostasis in breast cancer cells has not been explored. This study examined the underlying mechanism of cytotoxicity induced by esculetin and established the relationship between Ca(2+) signaling and cytotoxicity in human breast cancer cells. The results showed that esculetin induced concentration-dependent rises in the intracellular Ca(2+) concentration ([Ca(2+)]i) in ZR-75-1 (but not in MCF-7 and MDA-MB-231) human breast cancer cells. In ZR-75-1 cells, this Ca(2+) signal response was reduced by removing extracellular Ca(2+) and was inhibited by the store-operated Ca(2+) channel blocker 2-aminoethoxydiphenyl borate (2-APB). In Ca(2+)-free medium, pre-treatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin (TG) abolished esculetin-induced [Ca(2+)]i rises. Conversely, incubation with esculetin abolished TG-induced [Ca(2+)]i rises. Esculetin induced cytotoxicity that involved apoptosis, as supported by the reduction of mitochondrial membrane potential and the release of cytochrome c and the proteolytic activation of caspase-9/caspase-3, which were partially reversed by pre-chelating cytosolic Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM). Moreover, esculetin increased the percentage of cells in G2/M phase and regulated the expressions of p53, p21, CDK1, and cyclin B1. Together, in ZR-75-1 cells, esculetin induced [Ca(2+)]i rises by releasing Ca(2+) from the ER and causing Ca(2+) influx through 2-APB-sensitive store-operated Ca(2+) entry. Furthermore, esculetin activated Ca(2+)-associated mitochondrial apoptotic pathways that involved G2/M cell cycle arrest. Graphical abstract The summary of esculetin-evoked [Ca(2+)]i rises and -activated Ca(2+)-associated mitochondrial apoptotic pathways that involved cell cycle arrest. The natural coumarin derivative esculetin caused Ca(2+) influx via 2-APB-sensitive store-operated Ca(2+) entry and induced Ca(2+) release from the endoplasmic reticulum. Moreover, esculetin activated the mitochondrial pathway of apoptosis in a Ca(2+)-associated manner that involved G2/M arrest.