Glycogen Synthase Kinase-3 (GSK3) Inhibition Induces Prosurvival Autophagic Signals in Human Pancreatic Cancer Cells
Glycogen Synthase Kinase-3 (GSK3) Inhibition Induces Prosurvival Autophagic Signals in Human Pancreatic Cancer Cells
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DOI：
10.1074/jbc.m114.616714
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发表时间：
2015-02-27
影响因子：
4.8
通讯作者：
Boucher, Marie-Josee
中科院分区：
文献类型：
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作者：
Marchand, Benoit;Arsenault, Dominique;Boucher, Marie-Josee
糖原合成酶激酶3 （GSK3）是一种普遍表达的丝氨酸-苏氨酸激酶，参与从糖原代谢控制到转录调节的多种功能。我们最近证明GSK3抑制可触发人胰腺癌细胞中jnk - cjun依赖性凋亡。然而，gsk3调控的下游通路/功能的全面图景仍然难以捉摸。在此，抵消死亡信号，我们表明GSK3抑制通过增加自噬/溶酶体网络的活性诱导促生存信号。我们的数据还揭示了GSK3在胰腺癌细胞自噬和溶酶体生物发生的主要转录调节因子转录因子EB （TFEB）中的作用。与哺乳动物雷帕霉素靶蛋白（mTOR）抑制类似，GSK3抑制剂促进TFEB核定位，并通过内源性丝氨酸/苏氨酸磷酸酶作用导致TFEB去磷酸化。然而，GSK3和mTOR抑制对TFEB磷酸化的影响不同且独立，这表明TFEB是由一组激酶和/或磷酸酶调节的。尽管GSK3和mTOR抑制剂对TFEB磷酸化的影响不同，但它们都促进14-3-3解离和TFEB核定位。定量质谱分析进一步揭示了GSK3和mTOR抑制下TFEB与核蛋白的关联增加，这表明TFEB转录功能受到积极影响。最后，在完全喂养的胰腺癌细胞中，TFEB的主要核定位被揭示出来，而TFEB表达的减少显著损害了它们以非锚定方式生长的能力。此外，tfeb限制细胞在GSK3抑制后对凋亡更敏感。总之，我们的数据揭示了胰腺癌细胞中GSK3控制下的新功能，并为TFEB调控提供了关键见解。
Glycogen synthase kinase-3 (GSK3) are ubiquitously expressed serine-threonine kinases involved in a plethora of functions ranging from the control of glycogen metabolism to transcriptional regulation. We recently demonstrated that GSK3 inhibition triggers JNK-cJUN-dependent apoptosis in human pancreatic cancer cells. However, the comprehensive picture of downstream GSK3-regulated pathways/functions remains elusive. Herein, counterbalancing the death signals, we show that GSK3 inhibition induces prosurvival signals through increased activity of the autophagy/lysosomal network. Our data also reveal a contribution of GSK3 in the regulation of the master transcriptional regulator of autophagy and lysosomal biogenesis, transcription factor EB (TFEB) in pancreatic cancer cells. Similarly to mammalian target of rapamycin (mTOR) inhibition, GSK3 inhibitors promote TFEB nuclear localization and leads to TFEB dephosphorylation through endogenous serine/threonine phosphatase action. However, GSK3 and mTOR inhibition impinge differently and independently on TFEB phosphorylation suggesting that TFEB is regulated by a panel of kinases and/or phosphatases. Despite their differential impact on TFEB phosphorylation, both GSK3 and mTOR inhibitors promote 14-3-3 dissociation and TFEB nuclear localization. Quantitative mass spectrometry analyses further reveal an increased association of TFEB with nuclear proteins upon GSK3 and mTOR inhibition suggesting a positive impact on TFEB transcriptional function. Finally, a predominant nuclear localization of TFEB is unveiled in fully fed pancreatic cancer cells, whereas a reduction in TFEB expression significantly impairs their capacity for growth in an anchorage-independent manner. In addition, TFEB-restricted cells are more sensitive to apoptosis upon GSK3 inhibition. Altogether, our data uncover new functions under the control of GSK3 in pancreatic cancer cells in addition to providing key insight into TFEB regulation.