A novel and selective inhibitor of PKC zeta potently inhibits human breast cancer metastasis in vitro and in mice

作者：Wu, Jing^*; Liu, Shuye; Fan, Zhijuan; Zhang, Lei; Tian, Yaqiong; Yang, Rui^*

来源：Tumor Biology, 2016, 37(6): 8391-8401.

DOI：10.1007/s13277-015-4744-9

• Breast cancer
• Chemotaxis
• Metastasis
• PKC zeta
• Inhibitor

Cell motility and chemotaxis play pivotal roles in the process of tumor development and metastasis. Protein kinase C zeta (PKC zeta) mediates epidermal growth factor (EGF)-stimulated chemotactic signaling pathway through regulating cytoskeleton rearrangement and cell adhesion. The purpose of this study was to develop anti-PKC zeta therapeutics for breast cancer metastasis. In this study, a novel and high-efficient PKC zeta inhibitor named PKC(Z)I195.17 was screened out through a substrate-specific strategy. MTT assay was used to determine the cell viability of human breast cancer MDA-MB-231, MDA-MB-435, and MCF-7 cells while under PKC(Z)I195.17 treatment. Wound-healing, chemotaxis, and Matrigel invasion assays were performed to detect the effects of PKC(Z)I195.17 on breast cancer cells migration and invasion. Adhesion, actin polymerization, and Western blotting were performed to detect the effects of PKC(Z)I195.17 on cells adhesion and actin polymerization, and explore the downsteam signaling mechanisms involved in PKC zeta inhibition. MDA-MB-231 xenograft was used to measure the in vivo anti-metastasis efficacy of PKC(Z)I195.17. The compound PKC(Z)I195.17 selectively inhibited PKC zeta kinase activity since it failed to inhibit PKC alpha, PKC beta, PKC delta, PKC eta, AKT2, as well as FGFR2 activity. PKC(Z)I195.17 significantly impaired spontaneous migration, chemotaxis, and invasion of human breast cancer MDA-MB-231, MDA-MB-435, and MCF-7 cells, while PKC(Z)I195.17 did not obviously inhibited cells viability. PKC(Z)I195.17 also inhibited cells adhesion and actin polymerization through attenuating the phosphorylations of integrin beta 1, LIMK, and cofilin, which might be the downstream effectors of PKC zeta-mediated chemotaxis in MDA-MB-231 cells. Furthermore, PKC(Z)I195.17 suppressed the breast cancer metastasis and increased the survival time of breast tumor-bearing mice. In summary, PKC(Z)I195.17 was a PKC zeta-specific inhibitor which dampened cancer cell migration and metastasis and may serve as a novel therapeutic drug for breast cancer metastasis.

• 出版日期2016-6
• 单位天津市第三中心医院; 天津医科大学