Src, PKCα, and PKCδ are required for αvβ3 integrin-mediated metastatic melanoma invasion
Src, PKCα, and PKCδ are required for αvβ3 integrin-mediated metastatic melanoma invasion
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DOI：
10.1186/1478-811x-7-10
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发表时间：
2009-04-28
影响因子：
8.4
通讯作者：
Miranti, Cindy K.
中科院分区：
文献类型：
--
作者：
Putnam, Andrew J.;Schulz, Veronique V.;Miranti, Cindy K.
背景：整合素是一种细胞表面受体，介导细胞与细胞外基质(ECM)之间的黏附作用，在肿瘤进展中发挥重要作用。Vetronectin受体αvβ3整合素的表达与恶性黑色素瘤侵袭和转移能力的增加有关，但该整合素的表达如何触发黑色素瘤的侵袭和转移尚不清楚。结果：两株黑色素瘤细胞株C8161.9和M14均表达高水平的αvβ3整合素，并与Vitronectin黏附。然而，只有高转移的C8161.9细胞能够以αvβ3依赖的方式侵袭富含玻璃连结蛋白的Matrigel。在高转移性黑色素瘤细胞中，PKCα和PKC Delta表达水平升高，而在低转移性黑色素瘤细胞中检测不到。抑制Src或PKC活性可抑制依赖于αvβ3的侵袭。此外，Src或PKCA和PKCd的过度表达足以赋予M14细胞依赖于αvβ3的侵袭力。与M14细胞相比，C8161.9细胞几乎完全没有应力纤维形成和灶性粘连形成。抑制Src信号足以恢复正常的肌动蛋白结构，并导致p190RhoGAP磷酸化降低和RhoA活性增强。SRC对RAC活性无影响。SiRNA使PKCα表达缺失，但不影响PKC增量，从而抑制RAC和PAK的活性及侵袭力。PKCα的缺失恢复了局部粘连的形成和部分应力纤维的形成，而PKC Delta的缺失主要恢复了应力纤维的形成。结论：转移性黑色素瘤细胞中PKCα和PKCβ的错误表达以及Src活性的升高是αvβ3介导的有效侵袭所必需的。PKCα和Src增强αvβ3介导的侵袭作用部分是通过增加RAC相对于RhoA的GTPase活性。PKCα影响局部粘连的形成，而PKCd则控制应力纤维的形成。
Background: Integrins, cell-surface receptors that mediate adhesive interactions between cells and the extracellular matrix (ECM), play an important role in cancer progression. Expression of the vitronectin receptor alpha v beta 3 integrin correlates with increased invasive and metastatic capacity of malignant melanomas, yet it remains unclear how expression of this integrin triggers melanoma invasion and metastasis.Results: Two melanoma cell lines C8161.9 and M14 both express high levels of alpha v beta 3 integrin and adhere to vitronectin. However, only the highly metastatic C8161.9 cells are capable of invading vitronectin-enriched Matrigel in an alpha v beta 3-depenent manner. Elevated levels of PKC alpha and PKC delta, and activated Src were detected specifically in the highly metastatic melanoma cells, but not in the low metastatic M14 cells. Inhibition of Src or PKC activity suppressed alpha v beta 3-dependent invasion. Furthermore, over expression of Src or PKCa and PKCd was sufficient to confer alpha v beta 3-dependent invasiveness to M14 cells. Stress fiber formation and focal adhesion formation were almost completely absent in C8161.9 cells compared to M14 cells. Inhibition of Src signaling was sufficient to restore normal actin architecture, and resulted in decreased p190RhoGAP phosphorylation and enhanced RhoA activity. Src had no effect on Rac activity. Loss of PKC alpha expression, but not PKC delta, by siRNA inhibited Rac and PAK activity as well as invasiveness. Loss of PKC alpha restored focal adhesion formation and partially restored stress fiber formation, while loss of PKC delta primarily restored stress fibers.Conclusion: The misregulated expression of PKC alpha and PKC beta and elevated Src activity in metastatic melanoma cells is required for efficient alpha v beta 3-mediated invasion. PKC alpha and Src enhance alpha v beta 3-mediated invasion in part by increasing the GTPase activity of Rac relative to RhoA. PKC alpha influences focal adhesion formation, while PKCd controls stress fibers.