Frederick L A, Matthews J A, Jamieson L, Justilien V, Thompson E A, Radisky D C, Fields A P
Department of Cancer Biology, Mayo Clinic College of Medicine, Jacksonville, FL 32224, USA.
Oncogene. 2008 Aug 14;27(35):4841-53. doi: 10.1038/onc.2008.119. Epub 2008 Apr 21.
Protein kinase Ciota (PKCiota) drives transformed growth of non-small cell lung cancer (NSCLC) cells through the Rho family GTPase Rac1. We show here that PKCiota activates Rac1 in NSCLC cells by formation of a PKCiota-Par6alpha complex that drives anchorage-independent growth and invasion through activation of matrix metalloproteinase-10 (MMP-10) expression. RNAi-mediated knockdown of PKCiota, Par6alpha or Rac1 expression inhibits NSCLC transformation and MMP-10 expression in vitro. Expression of wild-type Par6alpha in Par6alpha-deficient cells restores transformation and MMP-10 expression, whereas expression of Par6alpha mutants that either cannot bind PKCiota (Par6alpha-K19A) or couple to Rac1 (Par6alpha-DeltaCRIB) do not. Knockdown of MMP-10 expression blocks anchorage-independent growth and invasion of NSCLC cells and addition of catalytically active MMP-10 to PKCiota- or Par6alpha-deficient cells restores anchorage-independent growth and invasion. Dominant-negative PKCiota inhibits tumorigenicity and MMP-10 expression in subcutaneous NSCLC tumors. MMP-10 and PKCiota are coordinately overexpressed in primary NSCLC tumors, and tumor MMP-10 expression predicts poor survival in NSCLC patients. Our data define a PKCiota-Par6alpha-Rac1 signaling axis that drives anchorage-independent growth and invasion of NSCLC cells through induction of MMP-10 expression.
蛋白激酶ι(PKCι)通过Rho家族小G蛋白Rac1驱动非小细胞肺癌(NSCLC)细胞的转化生长。我们在此表明,PKCι通过形成PKCι-Par6α复合物在NSCLC细胞中激活Rac1,该复合物通过激活基质金属蛋白酶-10(MMP-10)的表达来驱动非锚定依赖性生长和侵袭。RNA干扰介导的PKCι、Par6α或Rac1表达的敲低在体外抑制NSCLC的转化和MMP-10的表达。在Par6α缺陷细胞中野生型Par6α的表达恢复了转化和MMP-10的表达,而不能结合PKCι(Par6α-K19A)或偶联到Rac1(Par6α-ΔCRIB)的Par6α突变体的表达则不能。MMP-10表达的敲低阻断了NSCLC细胞的非锚定依赖性生长和侵袭,并且向PKCι或Par6α缺陷细胞中添加具有催化活性的MMP-10可恢复非锚定依赖性生长和侵袭。显性负性PKCι抑制皮下NSCLC肿瘤的致瘤性和MMP-10的表达。MMP-10和PKCι在原发性NSCLC肿瘤中协同过表达,并且肿瘤MMP-10表达预示着NSCLC患者的不良生存。我们的数据定义了一个PKCι-Par6α-Rac1信号轴,该信号轴通过诱导MMP-10的表达来驱动NSCLC细胞的非锚定依赖性生长和侵袭。