Reciprocal positive regulation between Cx26 and PI3K/Akt pathway confers acquired gefitinib resistance in NSCLC cells via GJIC-independent induction of EMT.
Reciprocal positive regulation between Cx26 and PI3K/Akt pathway confers acquired gefitinib resistance in NSCLC cells via GJIC-independent induction of EMT.
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Cx26 和 PI3K/Akt 通路之间的相互正向调节通过不依赖 GJIC 的 EMT 诱导赋予 NSCLC 细胞获得性吉非替尼耐药性
DOI：
10.1038/cddis.2015.197
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发表时间：
2015-07-23
影响因子：
9
通讯作者：
Qin S
中科院分区：
文献类型：
--
作者：
Yang J;Qin G;Luo M;Chen J;Zhang Q;Li L;Pan L;Qin S
由于耐药性的发展，吉非替尼在非小细胞肺癌（NSCLC）治疗中的疗效有限。吉非替尼耐药的分子机制仍不清楚。在本研究中，我们首次发现连接蛋白26（Cx 26）是在各种NSCLC细胞系中表达的主要Cx亚型。然后，建立了两个吉非替尼耐药（GR）NSCLC细胞系，HCC 827 GR和PC 9 GR，从他们的亲本细胞。在这些GR细胞中，结果表明吉非替尼耐药与细胞EMT表型的变化和Cx 26的上调相关。Cx 26在GR细胞或其亲本细胞中被检测到积聚在细胞质中，并且未能建立功能性间隙连接细胞间通讯（GJIC）。GJIC缺陷嵌合体Cx 26的异位表达足以诱导HCC 827和PC 9细胞中的EMT和吉非替尼不敏感性，而Cx 26的敲除在体外和体内逆转GR细胞中的EMT和吉非替尼抗性。此外，Cx 26过表达可激活这些细胞中的PI 3 K/Akt信号。抑制PI 3 K/Akt通路可显著阻断Cx 26介导的EMT和吉非替尼耐药。具体而言，抑制PI 3 K/Akt通路的组成性激活实质上抑制了Cx 26表达，并且证实Cx 26在功能上与PI 3 K/Akt信号传导相互作用以促进NSCLC细胞中的EMT和吉非替尼抗性。综上所述，Cx 26和PI 3 K/Akt信号之间的相互正向调节通过GJIC非依赖性方式促进EMT而有助于NSCLC细胞获得性吉非替尼耐药。
Gefitinib efficiency in non-small-cell lung cancer (NSCLC) therapy is limited due to development of drug resistance. The molecular mechanisms of gefitinib resistance remain still unclear. In this study, we first found that connexin 26 (Cx26) is the predominant Cx isoform expressed in various NSCLC cell lines. Then, two gefitinib-resistant (GR) NSCLC cell lines, HCC827 GR and PC9 GR, from their parental cells were established. In these GR cells, the results showed that gefitinib resistance correlated with changes in cellular EMT phenotypes and upregulation of Cx26. Cx26 was detected to be accumulated in the cytoplasm and failed to establish functional gap-junctional intercellular communication (GJIC) either in GR cells or their parental cells. Ectopic expression of GJIC-deficient chimeric Cx26 was sufficient to induce EMT and gefitinib insensitivity in HCC827 and PC9 cells, while knockdown of Cx26 reversed EMT and gefitinib resistance in their GR cells both in vitro and in vivo. Furthermore, Cx26 overexpression could activate PI3K/Akt signaling in these cells. Cx26-mediated EMT and gefitinib resistance were significantly blocked by inhibition of PI3K/Akt pathway. Specifically, inhibition of the constitutive activation of PI3K/Akt pathway substantially suppressed Cx26 expression, and Cx26 was confirmed to functionally interplay with PI3K/Akt signaling to promote EMT and gefitinib resistance in NSCLC cells. In conclusion, the reciprocal positive regulation between Cx26 and PI3K/Akt signaling contributes to acquired gefitinib resistance in NSCLC cells by promoting EMT via a GJIC-independent manner.