槲皮素诱导Hep G2自噬与胞内游离Ca2+浓度的变化相关

槲皮素具有诱导细胞自噬、抑制肿瘤细胞增殖等抗癌功能，但其诱导细胞自噬的分子机制还不太清楚. 本文通过激光共聚焦显微镜观察槲皮素对Hep G2细胞自噬的影响; Fluo-3 AM和Cyto-IDTM Green Detection Reagent染色标记, 流式细胞术测定了槲皮素对Hep G2细胞内游离钙离子浓度［Ca2+］_i 及Ca2＋螯合剂BAPTA-AM对自噬水平的影响. 探讨了槲皮素诱导人肝癌细胞 Hep G2自噬过程中［Ca2+］i的变化. 结果表明, 在槲皮素较低浓度范围内(0 ～ 50 μg/mL), 可明显抑制Hep G2细胞增殖, 并以剂量依赖方式诱导细胞自噬. 同时发现,槲皮素刺激Hep G2细胞可使［Ca2+］i明显增加, 进而促进自噬. 而当胞内Ca2＋螯合剂 BAPTA-AM存在时, 细胞的自噬水平受到一定的抑制. 这些结果表明，细胞内［Ca2+］i的升高可促进自噬, ［Ca2+］_i 的降低可能会抑制自噬. Hep G2细胞自噬与细胞内游离钙离子浓度的变化有关系.

Correlation between the Change of Intracellular Free Calcium Ion and Autophagy Induced by Quercetin in Hep G2 Cells

Quercetin has anticancer functions including induction of autophagy and inhibition of proliferation, but few reports were given on human hepatoma tumors and mechanism of autophagy of Hep G2. To understand the mechanism of cell autophagy induced by quercetin, we focused on the changes of intracellular free calcium ion concentration ［Ca2+］i during autophagy of Hep G2 cells. The effect of quercetin on autophagy of Hep G2 cells was detected by laser scanning co-focal microscopy. ［Ca2+］i and the level of autophagy were assessed by flow cytometry after Fluo-3 AM and Cyto-IDTM Green Detection Reagent staining. The results showed that the viabilities of Hep G2 cells were decreased and the autophagy was induced after treated with quercetin at concentration range of 0～50 μg/mL, while that of HL7702 cells were not changed significantly. Meanwhile, we also observed the effects of quercetin on intracellular free calcium ion and the relationship between autophagy and change of the ［Ca2+］i in Hep G2 cells. It was found that ［Ca2+］i in Hep G2 cells was increased significantly after treated with 50 μg/mL quercetin. However, autophagy was inhibited when incubated with an intracellular calcium chelator BAPTA-AM. These results revealed that ［Ca2+］i elevation can promote autophagy while the reduction of ［Ca2+］i may suppress cell autophagy. Autophagy induced by quercetin may be related to the change of intracellular free calcium ion.