Inhibition of Orai1-mediated Ca(2+) entry enhances chemosensitivity of HepG2 hepatocarcinoma cells to 5-fluorouracil.
Inhibition of Orai1-mediated Ca(2+) entry enhances chemosensitivity of HepG2 hepatocarcinoma cells to 5-fluorouracil.
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抑制Orai1介导的Ca2+进入增强HepG2肝癌细胞对5-氟尿嘧啶的化疗敏感性
DOI：
10.1111/jcmm.13029
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发表时间：
2017-05
影响因子：
5.3
通讯作者：
Pang RP
中科院分区：
文献类型：
--
作者：
Tang BD;Xia X;Lv XF;Yu BX;Yuan JN;Mai XY;Shang JY;Zhou JG;Liang SJ;Pang RP
越来越多的证据支持钙库操纵的钙内流（SOCE）的激活与接受化疗的癌细胞的化疗耐药性有关。然而，化学抗性的分子机制还没有很好地理解。在这项研究中，我们的目的是研究5-FU是否通过调节Ca 2+依赖性自噬诱导肝癌细胞死亡。[Ca2+]i使用fura 2/AM染料测量。Western blotting和免疫组化检测蛋白表达。我们发现5-氟尿嘧啶（5-FU）通过抑制PI 3 K/AKT/mTOR通路诱导HepG 2肝癌细胞的自噬性细胞死亡。Orai 1在肝癌组织中的表达明显增高。5-FU处理降低了SOCE和Orai 1的表达，但对Stim 1和TRPC 1的表达没有影响。Orai 1的敲除或SOCE的药理学抑制增强了5-FU诱导的PI 3 K/AKT/mTOR通路抑制，并增强了5-FU激活的自噬细胞死亡。相反，Orai 1的异位过表达拮抗5-FU-诱导的自噬和细胞死亡。我们的研究结果为Orai 1在肝癌组织中的表达增加提供了令人信服的证据。5-FU可通过降低Orai 1表达抑制SOCE诱导HepG 2肝癌细胞自噬性死亡。这些研究结果表明，Orai 1表达是肝癌治疗5-FU敏感性的预测因子，阻断Orai 1介导的Ca 2+进入可能是使肝癌细胞对5-FU治疗敏感的一种有希望的策略。
Increasing evidence supports that activation of store‐operated Ca2+ entry (SOCE) is implicated in the chemoresistance of cancer cells subjected to chemotherapy. However, the molecular mechanisms underlying chemoresistance are not well understood. In this study, we aim to investigate whether 5‐FU induces hepatocarcinoma cell death through regulating Ca2+‐dependent autophagy. [Ca2+]i was measured using fura2/AM dye. Protein expression was determined by Western blotting and immunohistochemistry. We found that 5‐fluorouracil (5‐FU) induced autophagic cell death in HepG2 hepatocarcinoma cells by inhibiting PI3K/AKT/mTOR pathway. Orai1 expression was obviously elevated in hepatocarcinoma tissues. 5‐FU treatment decreased SOCE and Orai1 expressions, but had no effects on Stim1 and TRPC1 expressions. Knockdown of Orai1 or pharmacological inhibition of SOCE enhanced 5‐FU‐induced inhibition of PI3K/AKT/mTOR pathway and potentiated 5‐FU‐activated autophagic cell death. On the contrary, ectopic overexpression of Orai1 antagonizes 5‐FU‐induced autophagy and cell death. Our findings provide convincing evidence to show that Orai1 expression is increased in hepatocarcinoma tissues. 5‐FU can induce autophagic cell death in HepG2 hepatocarcinoma cells through inhibition of SOCE via decreasing Orai1 expression. These findings suggest that Orai1 expression is a predictor of 5‐FU sensitivity for hepatocarcinoma treatment and blockade of Orai1‐mediated Ca2+ entry may be a promising strategy to sensitize hepatocarcinoma cells to 5‐FU treatment.