PKCδ Inhibition Impairs Mammary Cancer Proliferative Capacity But Selects Cancer Stem Cells, Involving Autophagy
PKCδ Inhibition Impairs Mammary Cancer Proliferative Capacity But Selects Cancer Stem Cells, Involving Autophagy
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DOI：
10.1002/jcb.25358
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发表时间：
2016-03-01
影响因子：
4
通讯作者：
Todaro, Laura B.
中科院分区：
文献类型：
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作者：
Berardi, Damian E.;Flumian, Carolina;Todaro, Laura B.
蛋白激酶C(PKC)是一个丝氨酸/苏氨酸激酶家族，调节多种细胞功能，包括细胞死亡、增殖和存活。最近的研究报道，PKC Delta参与了细胞凋亡或自噬的诱导。在本研究中，我们利用药理学和遗传学方法，重点研究了PKC Delta如何调节激素非依赖性乳腺癌细胞株LM38-LP的增殖和肿瘤干细胞(CSC)特性。我们发现，经Rottlerin处理的PKC Delta的药理抑制，通过细胞周期停滞，导致细胞质空泡的形成，损害了体外LM38-LP的增殖。免疫荧光实验证实，Rottlerin处理后，细胞胞浆中的Lc3点出现，自噬通量增加。另一方面，相同的处理提高了CSC的生长速度和自我更新能力。此外，Rottlerin预处理可诱导CSC在3D培养(Matrigel)中生长时形成“葡萄状”形态，通常与恶性表型有关，并且在体内接种这些细胞时会增加实验性肺转移的数量。RNA干扰下调PKC Delta可诱导自噬和增加CSC数量，表明这些作用确实是通过依赖PKC Delta的途径发挥作用的。最后，3MA处理可以逆转乳头球数量的增加，提示自噬机制是PKC Delta抑制诱导的CSC自我更新增加所必需的。在这里，我们证明了PKC Delta活性通过自噬机制发挥双重作用，既降低了乳腺肿瘤细胞的增殖能力，又调节了肿瘤干细胞的自我更新。J.细胞。生物化学。2016年117：730-740。(C)2015年威利期刊公司。
Protein kinase C (PKC) is a family of serine/threonine kinases that regulate diverse cellular functions including cell death, proliferation, and survival. Recent studies have reported that PKC delta, are involved in apoptosis or autophagy induction. In the present study we focused on how PKC delta regulates proliferation and cancer stem cell (CSC) properties of the hormone-independent mammary cancer cell line LM38-LP, using pharmacological and genetic approaches. We found that pharmacological inhibition of PKC delta, by Rottlerin treatment, impairs in vitro LM38-LP proliferation through cell cycle arrest, inducing the formation of cytoplasmic-vacuoles. Using immunofluorescence we confirmed that Rottlerin treatment induced the apparition of LC3 dots in cell cytoplasm, and increased autophagy flux. On the other side, the same treatment increased CSC growth rate and self-renewal. Furthermore, Rottlerin pre-treatment induced in CSC the development of a "grape-like" morphology when they are growing in 3D cultures (Matrigel), usually associated with a malignant phenotype, as well as an increase in the number of experimental lung metastasis when these cells were inoculated in vivo. The PKC delta knockdown, by RNA interference, induced autophagy and increased CSC number, indicating that these effects are indeed exerted through a PKC delta dependent pathway. Finally, the increase in the number of mammospheres could be reversed by a 3MA treatment, suggesting that autophagy mechanism is necessary for the increased of CSC self-renewal induced by PKC delta inhibition. Here we demonstrated that PKC delta activity exerts a dual role through the autophagy mechanism, decreasing proliferative capacity of mammary tumor cells but also regulating tumor stem cell self-renewal. J. Cell. Biochem. 117: 730-740, 2016. (C) 2015 Wiley Periodicals, Inc.