Department of Traditional Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, 81362, Taiwan; Department of Nursing, Meiho University, Pingtung, 91202, Taiwan.
Department of Nursing, Division of Basic Medical Sciences, Chang Gung University of Science and Technology, Chia-Yi, 61363, Taiwan; Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Chia-Yi, 61363, Taiwan.
Arch Oral Biol. 2018 May;89:49-54. doi: 10.1016/j.archoralbio.2018.02.006. Epub 2018 Feb 14.
Magnolol, a polyphenol compound from herbal medicines, was shown to alter physiology in various cell models. However, the effect of magnolol on Ca homeostasis and its related physiology in oral cancer cells is unclear. This study examined whether magnolol altered Ca signaling and cell viability in OC2 human oral cancer cells.
Cytosolic Ca concentrations ([Ca]) in suspended cells were measured by using the fluorescent Ca-sensitive dye fura-2. Cell viability was examined by 4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] water soluble tetrazolium-1 (WST-1) assay.
Magnolol at concentrations of 20-100 μM induced [Ca] rises. Ca removal reduced the signal by approximately 50%. Magnolol (100 μM) induced Mn influx suggesting of Ca entry. Magnolol-induced Ca entry was partially suppressed by protein kinase C (PKC) regulators, and inhibitors of store-operated Ca channels. In Ca-free medium, treatment with the endoplasmic reticulum Ca pump inhibitor 2,5-di-tert-butylhydroquinone (BHQ) abolished magnolol-evoked [Ca] rises. Conversely, treatment with magnolol abolished BHQ-evoked [Ca] rises. Inhibition of phospholipase C (PLC) with U73122 partially inhibited magnolol-induced [Ca] rises. Magnolol at 20-100 μM decreased cell viability, which was not reversed by pretreatment with the Ca chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA/AM).
Together, in OC2 cells, magnolol induced [Ca] rises by evoking partially PLC-dependent Ca release from the endoplasmic reticulum and Ca entry via PKC-sensitive store-operated Ca entry. Magnolol also caused Ca-independent cell death. Therefore, magnolol-induced cytotoxicity may not be involved in activation mechanisms associated with intracellular Ca mobilization in oral cancer cells.
从草药中提取的多酚化合物厚朴酚被证明能改变各种细胞模型的生理机能。然而，厚朴酚对口腔癌细胞钙稳态及其相关生理机能的影响尚不清楚。本研究旨在探讨厚朴酚是否能改变 OC2 人口腔癌细胞中的钙信号和细胞活力。
悬浮细胞中的胞质 Ca 浓度 ([Ca]) 用荧光 Ca 敏感染料 fura-2 进行测量。通过 4-[3-[4-碘苯基]-2-[4-硝基苯基]-2H-5-四唑-1,3-苯二磺酸钠]水溶性四唑盐-1（WST-1）检测法检测细胞活力。
20-100μM 的厚朴酚浓度诱导 [Ca] 升高。Ca 去除使信号降低约 50%。厚朴酚（100μM）诱导 Mn 内流表明 Ca 内流。PKC 调节剂和储存操作 Ca 通道抑制剂部分抑制厚朴酚诱导的 Ca 内流。在无 Ca 培养基中，内质网 Ca 泵抑制剂 2,5-二特丁基对苯二酚（BHQ）处理消除了厚朴酚诱导的 [Ca] 升高。相反，厚朴酚处理消除了 BHQ 诱导的 [Ca] 升高。用 U73122 抑制 PLC 部分抑制了厚朴酚诱导的 [Ca] 升高。20-100μM 的厚朴酚降低细胞活力，但用 Ca 螯合剂 1,2-双(2-氨基苯氧基)乙烷-N,N,N',N'-四乙酸-乙氧甲酯（BAPTA/AM）预处理不能逆转这种作用。
综上所述，在 OC2 细胞中，厚朴酚通过部分激活 PLC 依赖性内质网 Ca 释放和 PKC 敏感储存操作 Ca 内流诱导 [Ca] 升高。厚朴酚还引起 Ca 非依赖性细胞死亡。因此，厚朴酚诱导的细胞毒性可能不涉及口腔癌细胞中与细胞内 Ca 动员相关的激活机制。
